If you read the full report, the automaker with by far the largest gap between its claimed improvements in fuel economy and its actual on-the-road performance is General Motors. Much worse than VW and Mercedes (who also did very poorly), by this measure.
The source of the data is actually www.spritmonitor.de, which is a self-reporting mileage tracking site (like www.fuelly.com). With ~501k vehicles tracked and 8.885B kilometers tracked, the site represents ~17k kilometers per car of user-reported mileage information.
Is this the best, or a reliable source, of information to start the reckoning/witch hunt to come? I'm not sure.
I thought the same. In my anecdotal experience, drivers tend to get much lower than the manufacturer mileage because they optimize for things other than fuel economy (e.g., speed).
My dad taught me lots of tips on conserving fuel and thankfully I've exceeded the sticker numbers on every car I've owned.
But that's actually irrelevant for the cited report. What the referenced graph says is that from 2008 to 2014, auto manufacturers declared a certain increase in emissions/economy, real world people reported a different amount, and those amounted to, unique to GM in this report, a negative percentage in how well they achieved their claims. That is, on average, GM car fuel economy got worse over this period, or people's driving habits changed for GM cars. (I can't discount the possibility of something else is going on, such as an influx of a different type of car for GM over that period, I haven't read yet how they normalized the study and accounted for things like that).
Manufacturers report fuel consumption during a controlled environment, with specific driving habits, etc.
Real world people drive insane (at least in the US), and most wouldn't even re-pass their drivers-license test, so most assuredly do not have the best driving habits.
So drawing the conclusion that manufacturers are "lying" from the discrepancies between those two data sets is ridiculous.
It's irrelevant because unless both a) people changed their driving habits on average over that time frame to cause more emissions and b) that change was primarily limited to drivers of GM vehicles, then driver habits do nothing to explain the data.
> So drawing the conclusion that manufacturers are "lying" from the discrepancies between those two data sets is ridiculous.
Perhaps you should pay attention to actually what I said, not what you think I said. I didn't say GM was lying, I implied their numbers deserve extra scrutiny.
The whole controversy is over manufacturers reporting false numbers, i.e. lying.
Saying a manufacturer deserves extra scrutiny can absolutely be inferred to be an accusation of them reporting false numbers, i.e. lying.
My reading comprehension isn't at fault here.
Secondly, it's still irrelevant.
You would have to prove that an improvement at throttle position 0.10 over 5 years equates directly to an improvement at throttle position 0.40.
How an engine performs in condition A has no inherent relation to its performance in condition B.
So yes, I stand by what I said. Maybe before accusing people of "not paying attention", you should look at your own language and see if it's ambiguous?
> Saying a manufacturer deserves extra scrutiny can absolutely be inferred to be an accusation of them reporting false numbers, i.e. lying.
> My reading comprehension isn't at fault here
Except that I very clearly said "I can't discount the possibility of something else is going on, such as an influx of a different type of car for GM over that period, I haven't read yet how they normalized the study and accounted for things like that."
> Maybe before accusing people of "not paying attention", you should look at your own language and see if it's ambiguous?
You ignored clear text from me saying that it didn't necessarily indicate GM was at fault. What am I supposed to infer from that?
As to the matter at hand, you still seem to be under the impression that driver habits can account for a change in the numbers we are talking about, when that would mean that GM drivers specifically drive very differently than all other car drivers in the report. We are talking about number across the industry, categorized by manufacturer. Everything listed on the graph in question shows automakers overreporting gains, which could be driver habits. GM specifically shows vastly different numbers from event every other manufacturer, not just the reported numbers. I fail to see how driver habit accounts for a specific manufacturer being so out of bounds with it's own reported numbers (keep in mind engines are often shared across multiple manufacturers).
> You ignored clear text from me saying that it didn't necessarily indicate GM was at fault. What am I supposed to infer from that?
I didn't ignore anything.
I said the source of data is not irrelevant. That's my entire argument.
And I was specifically refuting your thesis that the source of data is irrelevant.
and, "as to the matter at hand", yes, driver habits can account entirely for the discrepancy in numbers. Flawed data can account for it. Poor sampling can as well.
The report seems to have come from a self reporting site in the EU. Are you asserting that a US car manufacturer has sold a uniform distribution of make/model/engine cars across the globe?
Are you also asserting that this site is getting a proper randomized sample of the car-buying population, such that they don't all have a similar complaint? In my experience, the people who report such things are one of two cases 1) Extremely Satisfied, or the much more common 2) Extremely Dissatisfied.
Are you then also asserting that if GM optimizes for test conditions, which they believe to be similar to normal driving habits, that their engines would be optimized to perform well under conditions that people actually drive in? That's just sloppy. That's like comparing data from your Dev environment to that from Production, I believe there have been a few academic articles to refute that as well.
But, ultimately, are you asserting that we should just accept the source of data as a source of truth, and never question whether or not that it's valid? Should I just go buy a bunch of tabloids and take that as my "new news", since.....the source is irrelevant, right?
> And I was specifically refuting your thesis that the source of data is irrelevant.
Please stop trying to tell me what my thesis is, as you've misunderstood my statements. The portion of the comment I was responding to is "In my anecdotal experience, drivers tend to get much lower than the manufacturer mileage because they optimize for things other than fuel economy (e.g., speed)." That, by itself, is irrelevant to the question as to why one manufacturer has vastly different numbers than another. As to testing methodologies, yes, this could entirely be testing error. I've never stated my opposition to that possibility. I have repeatedly stated my only intention was to say these numbers need more investigation.
I'm done trying to discuss this with someone who ignores what I actually state in favor of what they decide I must be implying.
The whole controversy is over manufacturers reporting false numbers, i.e. lying.
No, actually it isn't. The controversy is over manufacturers tuning their vehicles' engine behavior to give economy for the tests and for the tests only. By your criteria, that's not a problem but VW has already been bitten really hard by the revelation that they did this.
...You would have to prove that an improvement at throttle position 0.10 over 5 years equates directly to an improvement at throttle position 0.40....
The EPA has essentially said that if this isn't a least somewhat true, the manufacturers are breaking the law.
I'm not sure what your definition of alter is, but for me to alter means to lie.
They weren't simply optimizing for test conditions, they were outright lying during test conditions.
that's what the EPA is saying is against the law.
Here's the thing, and this is my main point:
If the EPAs test conditions reflected normal driving habits, there would be zero difference between Manufacturer reported numbers and real world reported numbers.
If the EPAs test is completely different from normal driving, then it stands to reason that there is no inherent correlation between manufacturer numbers and reported numbers.
IDK if you've ever been through an emissions test (like the ones GM actually goes through), but they're a complete joke as to simulating real world behavior.
So I threw together a histogram [1] of car CO2 emissions as reported by manufacturers for 1200+ model/engine combos. It's not exactly uniformly distributed, to say the least, there is a strong peak at 99 g/km etc. Now that's maybe not conclusive evidence that they are lying, but it's certainly suspicious.
I'm not sure what that proves, at least relative to what I'm saying?
IFF the EPA's regulatory test procedure accurately described/expressed normal driving habits, then the only way that numbers would differ between the real world and the reported numbers would be fraud/lying/alteration, like what Volkswagen Group engaged in (let there be no mistake, it WAS fraud/lying, not a case of poor optimization).
BUT the EPA's regulatory test DOES NOT accurately depict normal driving conditions.
In the current case, a manufacturer has to:
- Realize and Formally accept that the test procedure is inaccurate
- Optimize for:
- Simulated driving conditions, aka the Test Procedure
- Real life driving
To me, it looks like GM just didn't do any of that, and only optimized for the simulated conditions and not real world road conditions.
Depending how far out of wack the test procedure really is could explain the entire data-set.
So the point is that these official numbers should be taken with a generous pinch of salt.
Now, when you talk about GM, remember this is data from Germany, so GM essentially means Opel. Now I believe that before the quite successfull Insignia which launched in 2008, Opel were mainly known for cheap and efficient and small cars like the Corsa and Astra, while now they have a more premium lineup, and "Turbo" versions of several models.
Yes exactly, with a pinch of salt. Exactly what I was trying to say.
And yeah, I've driven a Chevy Spark, and that thing was so slow I could get out and walk faster. I could totally see people driving with their foot to the floor in it.
IDK if you've ever been through an emissions test (like the ones GM actually goes through), but they're a complete joke as to simulating real world behavior.
Does not matter. Your argument is something like, that by dumb luck auto manufacturers produced good emissions results and terrible results in the field.
As understand it, the EPA is saying that if a manufacture is engaged in your two stage approach, "Optimize for:- Simulated driving conditions, aka the Test Procedure [and achieve high fuel economy] - Real life driving [and achieve high power, low fuel economy]" then they are engaging in systematic fraud and are going to get hit big time.
You seem to think it's just a matter of technicalities in the test condition. I'd like references for that.
No. That's not my argument. It has absolutely nothing to do with dumb luck.
The EPA has a set of standards, and manufacturers optimize for those. That's it.
Cheating != optimization. Cheating is like a kid copying someone else's answers. Optimization is studying before the test. Completely different things. And optimization isn't illegal.
If you still don't get it, I don't know what to say, I can't explain it any further.
OK, I get that you saying "Cheating != optimization". That may be your opinion. It may be true in a moral sense.
However, I have good evident that VW's optimization was considered criminal in this instance. And Indeed, since many manufacturers do this, things are pretty dicey.
"“Developing an engine software to optimize certain aspects of an operation cycle that you know the parameters of is a challenge, but it is very possible,” says Thiruvengadam. “Knowing when to switch to the EPA-favorable cycle is the trick; it could be set up to detect the absence of steering-wheel movement, or, and this is known, we often turn off the traction control for testing purposes.” Either way, the result is the same: it turns the emissions controls on for EPA testing and off for real-world driving. Somewhat ironically, the presumed benefits of turning off the controls for normal driving include improved fuel economy and engine power." [1]
It's the old saw about the drunk looking under the light post for his keys, when he probably lost them in the alley; the light's better over here.
If you make laws that can't be verified then you can't enforce them. So you test for things you think you can actually test and hope everything works out.
Wiring up an exhaust sensor to everybody's car every time they need to renew their tabs and having them drive around the city is so infeasible as to be laughable. So they put your car on a dyno or even have you put it in neutral with the parking brake on and have you rev the engine a little bit and see if the tailpipe is a mess.
Nevermind that a lot of cars belch smoke only under load.
No matter how careful I am, it's hard for me to get lower than 130% of the fuel consumption reported by the manufacturer. Perhaps I can do 120% of the reported consumption at 90 km/h, but I can hardly get lower than 140% on the highway (130 km/h) and in city traffic.
Actually, it depends. Modern cars do better in rolling hills than on perfectly flat land, since they can cut fuel entirely on the downhill, and the climbs don't require that much extra fuel over just maintaining speed.
> Modern cars do better in rolling hills than on perfectly flat land, since they can cut fuel entirely on the downhill
This is physically impossible. Even if the car was perfectly efficient at overcoming the force of gravity on the uphill portions (which it is not), you cannot do better than flat terrain (unless by hilly you mean 'net downhill').
The StackExchange post that he linked lists several cases where it's possible. I was skeptical too - I was a physics major in college, I know all about potential vs. kinetic energy and rolling resistance. But engines are not perfectly efficient: you're going to lose some energy to internal friction within the engine, and to combustion efficiency, and to transmission losses, and to a number of other effects which vary based on speed, RPM, and torque. Add in an engine computer that's trying to minimize these effects based on inputs, and actual fuel efficiency will vary significantly from the simple "chemical energy in = kinetic energy out" model.
I've also observed the effect that the OP mentioned: in my Honda Fit, I get a fairly consistent ~45 MPG on 101 (completely flat highway terrain), ~40 MPG on 280 (rolling hills, highway), and ~43 MPG on 84 (across the Santa Cruz Mountains; ascends 3000 ft. in a series of tight switchbacks and then descends 3000 ft. in a wavy line). My working hypothesis is that the descent on 84 is consistent enough that the engine computer can idle the engine for all of it, burning no fuel - this is consistent with the car being nearly silent on the downhill, and of the instantaneous mileage display being stuck at its max of 80 MPG. Probably also helps that speeds are much lower, so there's less air resistance.
Anyway, the point is that cars are complex enough that the simple models you learn in Physics 101 don't really hold.
Engines are most efficient at WOT. Hilly ascents at WOT will burn the fuel more efficiently (even though you're using more). Add a descent in which the computer stops providing fuel and it's possible that you could get a better mileage.
It's known that you can get better fuel economy by oscillating speed on flat ground - using WOT to gain speed, coasting back down, opening up WOT again. This is because the engine is most efficient under load and the average consumption works out better. Adding in the hills would average this effect.
Generally not wide open throttle - see the efficiency maps I linked to in another reply. Generally peak is at somewhere around 1/2 to 2/3rds maximum output.
Wide open throttle and percentage of maximum output are two different concepts. An engine operating at partial throttle has higher pumping losses (pulling air past the partially closed throttle plates).
An engine operating at WOT but still producing a fraction of its maximum output is certainly possible (and generally more efficient than an engine producing the same output at a partial throttle setting). A diesel engine is almost always in this configuration (metering fuel but generally not restricting air with a throttle plate) and a gas engine at low RPM but WOT is also in this state.
If tuned for efficiency in that config, it can be very efficient and is how many piston airplane engines are regularly operated where fuel consumption is an important part of range (and operating economics).
I think you should reconsider "physically impossible". Sure, in some idealized situations, the statement you're responding to would be wrong, grievously wrong.
But the actual situation has two novel features: (1) the engine uses up power just by being on; (2) you must maintain a minimum speed in order not to block traffic.
If you put these constraints in, you can see that it's possible for a pulsed-acceleration strategy to win. You put in a pulse of acceleration to get up the hill, turn the engine off, and coast down, maintaining enough speed to keep up with traffic.
Now sure, without the minimum-speed constraint, you'd probably be better off flat, and possibly using a pulsed-acceleration strategy.
I haven't done the math, but I think it would be reckless to say it's "physically impossible" for all values of static energy use and slopes.
Take a look at the stack exchange answer the commenter above linked to.
I read years ago that pulsing was the most efficient strategy. Engines have very different efficiencies at different rpms and power settings. The idea with pulsing is to try to operate it at its most efficient rpm and throttle setting, which of course rarely corresponds to the speed over flat ground you'd like to be travelling at. Hence pulsing.
Yep, and this is why moderate hills are better. It's essentially constant speed pulse-and-glide. Just building and releasing potential energy rather than kinetic.
Not at all, in many vehicles. 6th gear in my car is quite long (Turns 1950RPM at 75MPH) and I have no problem maintaining speed on highway grades.
Even if you do downshift that doesn't necessarily mean you're being less efficient either. Being a bit higher up the rev range may actually put you in a better spot on the efficiency curve for a given power output.
ICUs are more efficient if you open the throttle more (up to a point...). So it could be possible that the extra potential energy you store going uphill at better efficiency makes a difference.
I recently purchased prius which has much better mileage than my previous car so I'm monitoring each of my trip.
I actually observed this and it is true in my case; I do get better mileage when choosing a route through a canyon than when using regular freeway.
I suspect though that the real reason is that it basically affects how I'm driving. When I ride in a canyon I can't accelerate much because there are constant turns, while on straight freeway I most likely will accelerate.
This also would explain why most of the time I get better mileage in traffic (the EV is used most of the time).
I cannot imagine a cyclist imagining this to be true!
Obviously aerodynamics play a part, however the cyclist's 'engine is cut' on the downhill and on big cross country roads no brakes need be used on the descents. When the 'engine' is on it goes at a certain not-quite-racing amount whether up hill or on the flat. But place a hill in the way of A to B and vastly more 'fuel' is used than A to B 'going the flat way'.
Consider a different visualization: what if instead of a hill, you were crossing a valley? Starting at the top of the hill, you coast down and make it most of the way up the other side. Are you certain this will take more energy than pedaling the whole way across the flat?
What if you can start by coasting 90% of the distance with zero expenditure of energy? What if it was 95%? Now assume that your chain is extremely rusty (low efficiency drivetrain). Would it be possible that the energy to go the short distance up the remaining hill (after coasting downhill and halfway up the other side) might be less than overcoming the friction of pedaling the whole way?
I'm not certain that they occur on a bicycle in the real world (perhaps you need a custom crafted rusty chain that has essentially constant high losses regardless of pedaling speed), but I think there are cases where the variable losses due to friction might make the hilly case more efficient than the flat.
(Yes, I realize that chain friction is not the dominant factor in the real world. It's a stylized example.)
The best terrain I've ever ridden a bike on was a well-paved path of little resistance over forrested dunes. You start on top of a dune, pedal a little on the way down (not a lot of effort) and arrive on the top of the next dune with nearly zero speed. Perfect coasting and a cool breeze most of the time.
Even a rusty chain is ridiculously efficient - in the high 90%'s. An ICE and drive chain is pitiful in comparison, so let's substitute the chain for a missing rear axle nut so that, when pedalling, the wheel pulls to one side and creates tangible frictional losses.
I grew up in a very hilly area plus I have done a few continental rides where hills can be graded nicely and go on for 10 - 20 miles with little change of gradient. The hope to coast up the other side of the valley never really works out as well as one might hope, with a road that goes down a big hill you are invariably pedalling on the lower reaches of the down hill part, even if you were doing a good 30+ mph at the top. This can be due to the valley heating during the day giving a prevailing headwind due to air expanding.
Meanwhile, in the steep hills I grew up in, you can get a measured 40+ mph, conservative guessing (I would be boasting if I mentioned top measured speeds as they can be quite incredible but 40 mph is the town limits speed and it is cool to exceed it on a bike). Clearly this speed scrubs off with aerodynamics not being favourable. So you really do not blissfully roll up the other side, roller-coaster style.
On a daily basis I go over an arched bridge that does have a hill leading in to it. So you can coast down the hill, up over the arch and on down the other side. The fun is to not pedal over the bridge, to be in 'roller-coaster' mode. This feels good, and easy, but there is a psychological factor going on here. One's brain is distracted by the 'roller coaster' (or traffic) and not really noticing how much of a slog things are.
Essentially the only way things could work out anywhere near how you imagine is if there is no atmosphere. The cost of speed is aero and you just do not get the free ride up the other side of the valley, period.
If it was quicker/more efficient to go up and down hills we wouldn't have land speed records be they by bicycle or rocket car set on dead-flat courses, would we?
With the sibling reply regarding undulating paths, that is part 'mind trick' as it is mentally stimulating going up and down like that. It is just an illusion...
However, I can in part rescue your line of thinking on this - muscle groups... I actually like hills and you can use your arms, legs and plenty of muscles in between to 'conquer' a hill. On the flat you are more likely to just spin (unless sprinting). Maybe if you factor in the baseline power your body needs for pumping blood around, maybe that could make things 'possible'.
But the more I think about it - no... Look at motorways and trucks. Trucks are more efficient than cars even if they have lots of wheels and no obvious aerodynamic considerations. Lorry drivers do not choose the undulating 'A road next to the motorway when one is available. They stay on the motorway doing their most efficient speed (as that is how to make a profit). Hills that any car or lorry could go up are cut through with motorways, to make things as flat as possible.
> If it was quicker/more efficient to go up and down hills we wouldn't have land speed records be they by bicycle or rocket car set on dead-flat courses, would we?
That's a total non-sequitur. Land speed record attempts happen in flat places to keep them from turning into AIR speed record attempts.
Nope. If your vehicle goes over a hump back bridge then maybe, but not if you go down one side of a valley and up the other side, obviously with an inverted wing shaped profile to the vehicle?
Did you read the linked stackoverflow discussion? I thought it made a convincing case that greater efficiency was possible across a valley given a sufficiently-aerodynamic low-rolling-resistance vehicle with an engine of non-constant efficiency. Would your intuition also say that analysis is wrong? Is it?
I suggest you enroll in a physics course, this is physically impossible for the average case of net-zero displacement at a near-constant speed (i.e. roundtrips).
There are scenarios where it's true, but there are a lot of factors involved (drag, power/efficiency curves of the engine, etc..., net-negative displacement, etc...)
My Subaru Outback has been a nice surprise in this area.
The combined highway/city mileage on the sticker was 24 mpg, and I've been getting 27 or 28 mpg for the entire 2 years I've owned it. For a while I was commuting between Denver and Boulder (about 45 miles each way) five days a week and taking it up to the mountains for hiking or skiing every weekend, so it's been over a wide variety of terrain.
I'm using the numbers on the in-car, computer, though, so maybe I should double check...
Car computers are notoriously inaccurate. I have observed errors up to 12% in vehicles from multiple manufacturers. Car computers can be helpful in a relative sense to tell you whether one style of driving is more or less efficient than another but they're basically worthless for absolute calculations. The only reliable way to accurately calculate fuel economy (in mpg units) is to divide the number of miles since you last refueled by the number of gallons to fill the tank.
One of the things I like most about my Jetta TDLie is that the DSG will downshift if you keep the brakes on for more than about 5 seconds. On long downhills I can take my foot off the brake for about half the trip down and the gearbox does the rest until the speed slowly creeps back up.
Except some models are significantly more off the mark than others. Maybe some owner populations have worse driving habits than others, but it's worth investigating.
This is by no means an exhaustive list, nor an authoritative one. Would love to hear other's thoughts on these:
- When accelerating, try not to over-extend the throttle. If the engine is at 2k rpm, you get just as much acceleration from 30% throttle as 100%, at half the fuel cost.
- Release the throttle well before you reach a traffic light/stop sign. Deceleration by engine will cause a smoother stop and gives the traffic light more time to turn green. You spend less fuel trying to reach the stop line, and spend less fuel accelerating again. Bonus points for shifting down while decelerating.
- Keep tires well-inflated and oil levels up. Less friction means less wasted energy on both.
- Choose the highest gear when cruising. Most cars since 1990 can do 50kmh (30mph) even in fifth gear, as long as you don't need to accelerate.
- Drive slower. Most car engines are most efficient around 3500 rpm, which maps to somewhere between 90-110 kmh (60-70mph). Most highways allow for a higher speed. Diesel engines have their optimum at 2000 rpm, or so I've been told.
Of course most of this works best with a stick shift. I've never driven an automatic.
You can do this for automatics too - you just have to learn where the shift points are and drive at the right speed. Lift up on the accelerator quickly to upshift, press it down quickly to downshift. One thing that I notice easily when riding is when the driver is constantly staying at only a few km/h slower than the shift point, causing the engine to spin faster and consume more fuel than necessary. It often means the car is louder and vibrates more too, so not a good thing overall.
This is harder to do for newer models with quieter engines and smoother shifts but older automatics have very noticeable shifts and engine noise to judge whether you're near the bottom or top of each gear. It's very noticeable in larger trucks and buses.
Edit: another point I'll add to the list is traffic light phasing - look far ahead and observe the timing of the lights, and adjust your speed so that you're not going too fast (you'll arrive at a light before it turns green) or too slow (it'll turn red very shortly before you arrive). Obviously, you should do this only if traffic permits, but it's a great "trick" (not so much a weird one) when you can get from your origin to your destination at a constant speed with nearly no stops.
You can usually get the shift points for a model from its technical manual. Depending on the car, those shift points can be modified as well (using the appropriate software and cable).
ICE and Diesel engines are most efficient at full throttle. There have been some tests that show, in certain conditions, that using full throttle to get to speed and then maintaining speed is a more efficient way to drive than gradual acceleration.
> - When accelerating, try not to over-extend the throttle. If the engine is at 2k rpm, you get just as much acceleration from 30% throttle as 100%, at half the fuel cost.
I have a CVT transmission and while I'm sure it is very smart I still feel like I could do better with a manual. I don;t like my car vey much, but it is too practical and cheap to change.
> I have a CVT transmission and while I'm sure it is very smart I still feel like I could do better with a manual. I don;t like my car vey much, but it is too practical and cheap to change.
Is it a actual Continuously Variable Transmission (CVT) or an automatic transmission? There's nothing 'smart' in a CVT since there's gears to shift between, and it's highly unlikely you're going to do 'better' under normal driving since the point of a CVT is to allow the engine to run at ideal RPM's no matter the speed.
A CVT has a pair of pulleys with variable ratios, and a big belt between them, to allow the belt to shift between ratios and find the best ratio.
CVT has some inefficiencies that can be improved by putting the gear selection process from an automatic onto a manual (with an automated sequential manual gearbox or a "double-clutch" transmission).
I did some tests on a long drive last week, for the Smart Forfour I had this was the fuel consumption. It was all along flat, straight parts of the highway. Reports were based upon the cars own fuel efficiency monitor.
It's actually neither square nor cubed, but you can use those approximations with varying success for different car shapes and Reynolds numbers. There are several different physical effects that together create drag: you have form drag, skin drag, interference drag, and even lift-induced drag (the last one essentially only on sports cars).
Aerodynamic drag i.e. force opposite the direction of travel is proportional to the square of your velocity. Power consumption for steady cruising is equal to drag multiplied by speed. Thus power consumption is proportional to the cube of speed.
Right. And if you're measuring miles per gallon, you're interested in energy consumed per mile traveled, not energy consumed per second. And aerodynamic drag tells you energy consumed per mile traveled thanks to the relationship that energy is force times distance.
A dramatic demonstration of this is the Bugatti Veyron. Between the original version (1,001 hp) and the SuperSport version (1,184 hp) - the top speed only increased from 408 kmh to 431 kmh. So a 183 hp increase in power yields only a 23 kmh increase in top speed - bearing in mind that 183 hp is more than most passenger vehicles have in total.
It gets exponentially harder to push air out of the way the higher the speed gets.
Whether it's the most reliable or not, to me the indicated graph at least shows something massively different going on with some GM cars. Every other manufacturer ranges from achieving ~20% to 80% of their claimed fuel emissions improvements from 2008 to 2014, and then there's GM, all by itself with negative 40%.
That is, for GM cars alone, people are reporting not just a lack of increased fuel economy, but that it's gotten significantly worse. Whether it is accurate or not, it indicates something very wrong, either in the testing or in those cars, and that deserves some serious attention IMO.
Edit: s/fuel economy/fuel emissions/ Graph says economy, subtitle say emissions, text says emissions.
For starters, the average person probably drives a great deal more aggressively than the fuel-economy ideal. At least, the automotive industry is convinced enough of this to install behavior-modification techniques like "eco scores" into dashboards.
The official .gov propaganda is a 3% penalty, but self reports vary from 5% to 15%. E10 is a thirsty fuel and people buy a lot of groundwater at gasoline prices, which likely accounts for some variation.
Bizarrely the NEDC procedure allows carmakers to actually declare (use) a value 4% lower than the
one measured. The provision is designed to minimize the testing burden but is being abused by
carmakers to declare lower test results systematically."
I wonder if there is a person that didn't expect this to happen.
This is going to sound backwards, but consider this: People buy cars based in part on MpG, however MpG is within itself an abstract thing (i.e. you don't actually get X miles per gallon, never did, never will too many other factors to include).
So if everyone removes 4% from an abstract number, the entire market has shifted down, but the relative difference between two models remains identical (e.g. if one car has 21 MpG and another has 25 MpG, even with 4% removed from both they retain their relative position).
If some were removing 4% while others weren't, that would legitimately be a problem. If they're all removing 4% then we're essentially where we would be at the start just with lower abstract numbers.
>you don't actually get X miles per gallon, never did, never will too many other factors to include
This wouldn't be hard to fix.
Loan cars to a random selection of non-professional beta drivers.
Graph the results, showing the median and sd.
It would be cheaper to do this than to get hit by a class action for misleading buyers.
Of course reality-based non-expert mpg would look very bad compared to the dishonest figures you get now. But that's because of manufacturing and design decision, and not really the fault of the drivers.
In the US the EPA confirms the MPG ratings for 10%-15% of vehicles and has prescribed (edit: prescribed vs proscribed) testing regimes for each of the estimates. The issue isn't with manufacturers lying so much as the test schedule laid out by the EPA just doesn't reflect how people drive.
It does because emission regulations are not there for comparison purposes alone. We need to reduce emissions to a certain level, and the environment won't be fooled. This is similar to the way unemployment is now calculated based on active job seekers rather than people who are, well, unemployed.
Wow. I thought about shorting GM, after the VW thing broke. I figured they would have the highest incentive to cheat and everyone is about to get caught.
You're also assuming that execs necessarily knew about everything. There's a reasonable chance that the execs set the targets and feed it to the middle managers who pass it along to teams.
Somewhere along the line I imagine there are those who are terrified of missing those targets and perhaps losing their jobs and resort to bending the rules a bit to hit their goals. And there's a very good chance that these people aren't at the top.
The same was most likely true in the subprime mortgages--I imagine that some of the worst actors in that weren't necessarily the people at the top, it was the guy who is decidedly mid-level who is looking to make a nice bonus to put in a swimming pool for his kids.
And to figure it all out is going to take years and years of investigations to assign blame (whether in this case or in the subprime case). By the time it's sorted out, it could be a decade after the fact, and even then people have moved on to other jobs, records are difficult to dig up, and at the end of the day, what has been accomplished?
Of course if there is blatant wrong-doing, execs should absolutely be punished (the peanut company CEO comes to mind [1]). But it's extremely difficult to pin down blame on any one person, exec or not.
You can't just lock up the execs without evidence, that's unjust.
You can't just investigate, the nature of large power structures is that some underling will take the fall.
Breaking the rules for economic advantage should be met with new rules to force economic disadvantage. Put a 2% tax on total revenue for the next X years, possibly with the addition of a fee based on perceived past benefit. Honest players in the market will reap the lower cost of doing business, and better business practices will prevail.
The evidence is that X underling, which Y exec is directly responsible for the business conduct of, demonstrably broke the law in Z way. Vicarious liability I beleive is the term I'm looking for.
Again - with taking the credit comes taking the responsibility. I'd like to see the law amended as such.
Put fear of prison into the people at the top and they'll find a way to prevent this, or subprimes, or—hell—Enron from ever happening again. The buck has to stop somewhere[1]
Well, if the trickle-down theory says that execs and management get the most shares of profit trickling down, maybe the punishments should flow the same way...?
I would compare it to involuntary manslaughter vs first-degree murder. Inaction, negligence, lack of oversight etc that allows bad things to happen, when you were in the position to prevent it, should be punishable.
US regulatory bodies have no teeth and we've already propped up GM once. The only reckoning that's coming is going to be another round of market jiggling, or maybe an unrecoverable failure.
If you assume perfect burning then all carbon burned will turn into CO2. Therefore more CO2 may actually mean more efficient burning and smaller fuel usage (for the same amount of power i.e. less CO, less other particulate matter).
This could happen for example when the engine could not take enough air to burn efficiently (for example because it is stationary).
Unless we have also fuel consumption we could not know which case we are dealing with when we only see CO2 emissions.
For example when the test only measures (and prioritises) CO2 emissions, injection software may decide to use more fuel in inefficient manner to reduce the CO2 emission and then use exhaust filter to capture the extra particulate matter. Well, it is only a wild speculation, but it could be.
The problem is that the report authors do not explain their methodology and interchange freely fuel consumption and CO2 emissions without clear explanation (did they measure CO2 emissions directly? did they calculate it from fuel consumption?).
This is not proper reporting in my mind.
Beside they base their reporting on self reported (i.e. not automatically measured) data from http://www.spritmonitor.de/ that does not provide any objective information about the driving cycle.
See for example these two entries for BMW 3er 320d touring efficient dynamic
Well, maybe the first driver drove very carefully. Maybe the other car is broken or the driver likes to accelerate a lot or is driving on the hilly terrain.
It is also not known how many kilometers were driven on the city roads or highway as they are hard to separate in the data.
We also do not know which driving mode (eco, normal, sport etc) was used as it is not reported.
Car makers report different fuel consumption or CO2 profiles. Against which was comparison completed?
I think that this is sensationalist reporting with an agenda that is not well executed.
>Mercedes cars have the biggest average gap between test and real-world performance, with real-world
fuel consumption exceeding test results by nearly half.
Yes, your facts are valid too, but that's a different comparison than the one I am citing. Read my comment word-for-word and you will see the difference.
It's not my comment. It's data presented in the report. My comment is taken directly from the chart I cited. So if you want to quarrel with it, you need to quarrel with those who compiled the data, I suppose.
You first misread my comment, and now you're misreading the chart, apparently, so let me explain: the chart I cited shows the percentage of claimed improvement in fuel economy which was actually delivered in real-world driving.
This is precisely what my comment said.
Edit: I think your confusion might lie in the math that you think is being done, perhaps? The chart is showing the DIFFERENCE between two numbers. It's not based on just the claimed improvement. It's the actual improvement divided by the claim.
GM made a claim of improvement and their performance actually went down, so their number is around -38%. Daimler was the next-worst at around 16%.
"On average, two-thirds of the claimed gains in CO2 emissions and fuel consumption since 2008 have been delivered through manipulating tests"
How deep does this rabbit hole go :(
Here in Ireland the motortax for cars newer than 2008 is based on CO2 emissions, if motorists find their tax rising due to cheating by car manufacturers thats an unexpected and direct cost to their wallets.
None of this is really new, the mostly German car lobby has resisted European emissions testing on testing strict real-world usage, as opposed to testing on a roller.
Anyone who spent 10 minutes looking into this in the past years could've told you that, and it wasn't some big secret. A lot of it was stuff everyone was doing, like fitting certain tires and inflating them such that the rolling resistance is reduced. At the end of the day, there are limits to those gains and everyone does it, so in can't set you apart from the competition and once the basic manipulations are exhausted and the emissions goalposts are moved you can't make gains anymore without actually improving the car. Further most of these are for CO2 emissions / fuel efficiency, which is different from the VW fraud which was about NOx emissions.
The difference with the VW case is that VW essentially defrauded the test by building a device that measured various factors to establish whether it was being driven normally or whether it was being tested. In the former case it'd shut down (allowing 35x the legal limit of NOx emissions into the air while driving), while in the latter case it'd dampen the emissions (at the cost of engine performance, which is why they shut it off during regular driving). That's a different level of fraud, one that has very few bounds and can change results by much more than an order of magnitude, and is hugely controversial because it makes every test meaningless in the short, medium and long term and isn't practiced by everyone, and so different from manipulating tests by e.g. inflating tires which can still produce meaningful test, benchmarks and comparisons, when you start building 'defeat devices' all of that goes out the window completely.
In the UK we pay an annual tax [0] based on the engine size or CO2 emissions of the vehicle, in addition to tax on fuel.
I doubt the government will move affected cars up the price bands post-purchase as it would be politically unpopular.
One way or another, regular folks will pay for it. If it's directly by paying this tax, that's straight forward. Otherwise, the company will take the hit, and the cost will flow towards stock-holders, which in general tend to be unions, 401k plans and such. How much of your 401k are you willing to lose due to that cost? How much of your parents' 401k/union pensions is OK to forfeit?
That sounds like an argument for never punishing corporations for anything, which is clearly unworkable.
Pension and 401k plans are typically diversified across a broad range of stocks, so they won't be heavily impacted by a single company's stock price dropping. On the other hand, executives and board members, who are actually responsible for the company's actions, will typically have a large amount of that company's stock so they will be much more heavily impacted by the stock price dropping.
That's not how I meant it, but I can see how that's a fair reading of what I said. I don't like that people jump onto ideas very quickly without thinking through the ramifications. I don't think a lot of people realize how wide-reaching effects from quick knee-jerk reactions can be, and how much they can actually have effects beyond the first-order ones.
Yes. Optimising for c02 reductions over Nox and particulates is a monumentally stupid policy.
Co2 may have a deleterious effect in 100 years time, but is not an issue for air quality today. In any case, passenger vehicle c02 emssions are a rounding error in the scheme of things.
Meanwhile, particulate pollution and Nox are very real issues affecting millions of people today. It's stupid to push diesel over gasoline for c02 reasons.
Part of the reason VW cheated was because the USA didn't fall into this trap and allow more lax emissions standards for Diesels - all fuels are held to the same standard. So they took the Euro engines and added the defeat code.
The USA is correct on this one.
The focus on passenger vehicles is idiotic though - the amount of Nox and particulates pumped out by a single container ship is immense compared to a fleet of passenger vehicles. Then add trucking, rail, stationery equipment etc...
Cities should be optimising for electric propulsion and punishing diesels. That makes sense for air quality right now, and if co2 proves to be an issue, it is easily fixed by switching the generation source to Nuclear or Hydro.
Also because US cities are much more sprawled, and are often organized in neat, efficient grids instead of having formed organically over the course of ~2300 years. Compare maps of Paris with any US city.
That both suprises me, do you have any sources? Honest question, both seem counterintuitive. Maybe I am actually fed enough "feelgood" information in the past.
That is an article from greenpeace about poor EU environmental standards in power stations. Sure it is bad but, it does not compare air pollution in EU vs US cities or attribute anything to cars.
That goes against my subjective experience. The contribution of buses and trucks in US cities is also significant, and my sense is that EU regs on those vehicles are more stringent than US. I particularly tend to notice how much -noisier- large US vehicles are than European equivalents in a city traffic environment, which tends to correlate with lower efficiency.
See for example Paris's recent (yesterday?) "no car day" in the center. The city's usual blanket of smog is gone. France of course having the highest %age of diesel cars in its passenger fleet of any country.
Paris is one of the densest cities in the world[1], placed 6th if you disregard cities with a population of less than a million. It's the most dense large city among G8 countries. The only vaguely comparable European cities are Athens and Barcelona, both smaller and less dense. London has about a quarter of the density of Paris. The most dense large German cities, Munich and Berlin, less than a quarter. The city I live in -- part of one of the world's largest conurbations --, less than a tenth.
Statistics like these should be taken with a grain of salt (for one thing, city delimitations are fairly arbitrary), but the details are not worth haggling about: the point is that Paris is not at all representative of large European cities.
All European manufacturers except Renault and BMW are hellbent on not offering attractive E mobility solutions, despite really expensive and extensive internal research programs. We in Germany have a large numbers of Smart cars in car sharing companies that are sponsored by Daimler, but it's not yet economically viable to actually buy an E-Smart (if you've driven one, it's not bad at all).
It's strange. Europe should be a better market for electric and hybrid cars, given the higher petrol costs, but I guess the high purchase costs are putting people off.
I'd buy one if I did enough miles. It's not worth it for a few thousand a year. Even having a petrol car sitting on my drive is an expense of marginal justifiability.
Or maybe we abolish nonsensical, contrary requirements?
Whoever actaully believed the fuel consumption figures is a fool. You cant have a 1,5t of a car and expect it to use only 5l/100km.
That's a good rate for a goddamn motorbike (450ccm,one piston, dont exceed 90 km/h and you might reach 4,5l/100km) Its one fifth of the mass...
Well sorry for being a fool then. It's impossible to investigate everything about every part of our lives, and personally I feel a bit cheated by these revelations.
I think most people are aware there could be cheating, but not on the scale being claimed. I don't think it's unreasonable to have placed a bit of trust in the number.
Of course they do. People have limited time and energy and can't possibly be expected to have a good enough understanding of everything they touch in their daily lives to be able to "understand" them well enough to have sufficiently calibrated bullshit detectors for them all.
Maybe you're an expert in ICEs and this was obvious to you. Would you notice if your cell phone charger was actually pulling 10 amps out of the wall instead of the 1 it was rated for? What about if your non-GMO strawberries were actually created in a lab? Your organic beef injected with hormones?
The whole point of having these standards is so that consumers can rely on them and don't have to independently analyze everything they buy themselves.
They didn't call those bands "rage against the machine" and "public enemy" for nuthin now did they? I mean, in all seriousness, why be so serious? Simple points need to be understood, not simply dismissed out of hand. In theory everything the government or your employer tells you is true. In reality, they have alot to gain from asymetric information distribution, both in terms of negotiating financial outcomes but also in terms of maintaining their political power base.
All you have to do is look at how much gas you put in the damn thing and divide by how much youve driven since you last topped up. Not a deep investigative effort
That's like saying someone threw a rock at you and because you didn't look around before it hit you, its your fault.
The cheating is the problem, not the fact that people are ignorant about it.
Sorry, that BS. Nobody wants to conduct a research experiment every-time they purchase splenda to see if it might give them cancer in 10 years. It is impossible to live life that way. Social guarantees that your water supply does not contain poison, and that the car you purchase doesn't not fall apart and kill you at 45 mph when it worked fine at 20mph when you did the test drive, are and should be expected. Just because cheating is widespread does not make it your fault for not knowing it.
nobody wants to read website TOS either, but that's not how the world or the law work. there is a line between 'street smarts' and blind faith in people you don't know telling you stuff. 2x4's are not 2x4...that's something everyone probably should know...similarly, EPA fuel mileage is not accurate...and never has been...its not anyone's fault that everything in the world is not "literally" true
The same transaction costs argument for regulatory disclosure apply to the quality of such disclosure as well. Ever try reading nutritional labels? It goes on and on...has very little to do with one particular instance.
That being said, a auto is a capital good and a substantial purchase and investing some time to understand the buying process is both economic and sensible. so in this case the faux shock/outrage seems particularly misplaced...as the arguments for ignorance are weak indeed.
I actually drove my Golf TDI at around the level of 5l/100km in Berlin for many years. Carefully. My girlfriend's Polo is significantly below that. Of course, these cars aren't ton and a half, but more around a ton.
Yup. Diesel cars can pull of 5l/100km quite easily (even VW Passat from 1998 can do that). My diesel Skoda Fabia consumes 4.6l/100km at 90kmh in highway. If conditions are not terrible, I hover around 5l/100km on average in mixed conditions (city and highway). Though few major traffic jams can ruin statistics pretty badly. Also in winter average is about 5.6l/100km.
Maybe /user/emp_zealoth had petrol cars in mind? I've not personally seen a petrol (non hybrid) car consuming less than 7l/100km and when I had one it was 10l/100km (8 if I was lucky) and it was small Peugeot 306.
To rant even more.. IMHO, those fuel consumption tests are a total fraud. Look at new diesel sedans, local dealer declares that huge VW Passat TDI uses 4l/100km, or Skoda Octavia TDI (GreenLine or something) uses 3.1l/100km. Maybe it's true when you're driving at 90km/h with wind blowing in your tail and slight downhill.
Apart from Up, the other two models you listed are for the above-average-middle-class-people, so to speak, at least in Europe. Most of the car-owners in Europe drive hatchbacks like Opel Corsa (average weight 1200 kg) or Skoda Fabia (average weight 1100 kg).
I agree that cars are very heavy now, though, usually there are few 'types' of car weight. I do not know which where is used.
Usually there are 2 weights: unladen weight and maximum weight. I've heard about some third weight which is between the unladen and maximum weights, something like a car's weight with full tank and a driver, but don't quote me on this.
Probably you have the maximum weight listed. My Skoda Fabia (Audi Q3 equivalent) has maximum weight of 1680kg and unladen weight of 1200kg. I refuse to believe that VW Up is heavier than the Skoda Fabia.
AFAIK, minivans have quite big weight on their papers, but empty minivan can't weigh 3000kg, which is only possible if it's loaded.
My old '89 Chevy S-10 weighed just over 1700 pounds (770 kg) empty. At 55 MPH (90 kph) on the freeway (back when that was still the limit), it got about 30 MPG (13 km/l / 7.7l/100km). OK, not great mileage, but what do you want for 80s US car tech :-)
For safety reasons, or whatever, they don't make mini trucks in the US any more. I did a double take on a new Dodge "Dakota" in the store parking lot the other day. It looked just like a full size pickup as far as I could see.
It wasn't for safety. Compact trucks have too small of a footprint to get away with the CAFE requirements for their size so manufacturers either supersize them (Dakota) or eliminate them altogether (Ranger).
Audi Q5 weights 1850 kg according to wikipedia (https://en.wikipedia.org/wiki/Audi_Q5), although this obviously depends on the engine. 2470 kg looks more like maximum allowed weight of car + passengers + cargo.
Yeah, I checked for the Polo, empty weight appears to be 1050 kg. The Golf TDI was a '96, so given the trends I expect it to be roughly similar. The original Golf I was under a ton.
Audi claims 22mpg city, 32mpg highway and 26mpg combined.
What I see is 24mpg city, 31mpg highway and 26mpg combined; I don't drive especially slow either. FWIW, I factory ordered a manual transmission so that may make a difference.
I'm skeptical of cars that claim crazy high MPG ratings and performance cars claiming good MPG numbers, but for a standard car I do expect the numbers to be achievable. I've gone through a lot of cars over the years and I've gotten very close to the published numbers on all but one (Cadillac CTS).
Those numbers (37.2 miles per imperial gallon) are in the 3.0 TDI territory for Audi in the British(/EU?) market. Many would be disappointed with 37.2 highway for any 2.0 diesel engine: look at the 'Real MPG Avg' column at http://www.honestjohn.co.uk/realmpg/audi/a4-b8-2008
I don't think they're especially good or bad, my point was just that they are almost exactly what Audi claimed.
After the VW news I'm rather happy I went with petrol. Actually I never gave diesel a thought because Audi doesn't sell A3 or A4 diesels in the US (at least dealers don't have them and the website doesn't show them).
Your comparison with motorcycles is a bit flawed. Weight is the wrong thing to look at; at highway speeds drag is a major factor and motorcycles actually have higher drag coefficients than cars. You're also understating motorcycle fuel economy: I can easily get 4.5L/100km on my 600cc I4 doing 100km/h (although I more typically drive 130km/h and get 5L/100). I have friends who regularly do < 4L/100km in practice (on a 250, though).
My Chevrolet Sonic (with a 1.4L turbocharged gasoline engine and a curb weight of around 1.4 US tons or 1.5 metric tons) gets 42-ish MPG (5.6 L/100 km) during the summer and my driving conditions aren't even ideal (half my commute is highway speeds with stoplights). A Toyota Prius (Auris) could probably get more than 50 MPG (less than 4.7 L/100 km) on the same route.
A larger part of fuel consumption is driving behavior. My Ford Fusion (non-hybrid) only gets about 15 mpg in city/rush-hour driving because I drive very aggressively...but nearly 40 mpg on the freeway using cruise control (set to 75-80mph).
Comparing to known fuel effiencies of existing vehicles competely misses the point, which is to stimulate new technology development. For example, aluminum and plastic car body pieces, which reduce weight.
If you want to talk about "believable," start from basic physics and calculate the best possible fuel efficiency that a car could be expected to deliver. Even taking into account available materials, fuels, and engines, the answer is way better than what regulations currently require.
A lot of the expected gains will come from taking known "custom" solutions and scaling them up to mass market--like greater use of aluminum, and ultimately, composites.
> You cant have a 1,5t of a car and expect it to use only 5l/100km
So you are telling me that my actual, measured fuel consumption numbers of 4.25l/100km on flat highways in the US South are impossible? I have a diesel Passat (yes, one of the NOx Boxes :P) and can get from Dallas, TX to Pensacola, FL (650 mi) without refueling and with a decent reserve (~2 gallons) still in the tank.
What are you on about? For any given type of fuel, fuel consumption is related exactly 1:1 proportionately to CO2 emission (as carbon particulate and CO emissions are microscopically small these days). That is basic chemistry - where else would the fuel go?
Therefore any claim about CO2 emissions equates to a claim about fuel consumption.
The problem is that these findings do not reflect my anecdotal experience.
I have two recent measurements. About 500 km round trip and small trips inside the city.
This is accordingly about 17% and 21% increase (and it was in the same region for the older model of the same car).
Sorry, I did not include the make and model of the car because I do not want to leak too much personal information but it is nowhere close to the claimed difference.
Even more the round trip was mostly on the highway and included small city part (let say about 20 km). This differs from the official test cycle.
Also the city traffic includes high elevation differences and very bad slow traffic with constant stopping.
Also the car was more occupied in both cases (official tests consider about 70 kg driver and 7 kg luggage).
This means that in more fair test the results should be even more close to the official numbers.
So what could explain this?
I do not know as we do not see the fuel economy numbers.
Perhaps during the official tests the car is actually stationary and can not take enough air and the burning is not that efficient but a good exhaust filter hides this problem?
What is also strange is the difference between BMW 3rd series and 5th series because both use the same engines (and also some Renault models do use BMW engines but it do not know about Megane).
I calculated the fuel consumption and CO2 ratio for several models and it is about the same (as expected).
I also calculated weight to CO2 ratio for similar engines over few series and this gave also very similar results. As the different series look quite similar these days then I would assume that they also have quite similar aerodynamics.
After carefully reading again what they stating stating, it appears that even when they talk about CO2 emissions, they actually base their claims on self reported fuel consumption data from http://www.spritmonitor.de
It looks to me that the following is entered (I have not used the app) by the users.
Objective data:
Date of fuelling,
Current odometer value,
Amount and price of fuel.
Type of tires (summer/winter) [should be mostly objective]
Subjective data:
Driving style used (Moderate, Normal, Fast),
Roads driven (Motor-way, City, Country roads)
For roads driven all the options could be selected and are then doubly reported in the detailed statistics.
This means that there is no objective acceleration and speed profile and also elevation difference data is missing (is not collected).
To illustrate this I will compare two different entries for BMW 3er 320d touring efficient dynamic
In addition to what MagnumOpus said, CO2 emissions are irrelevant. I was calling them on a particular statement they made that I found to be ridiculous.
The requirement was to incentivise more efficient cars. Manufacturers just decided to ignore the requirement and lie about it instead. Customers decided to believe them.
Cars keep getting bigger and heavier. The current Golf -- nominally a compact car -- is half a meter longer (at least 4.25m) than the first one and half a ton heavier (at least 1.2t).
Your numbers are also false for motorcycles (which all run on gas and not diesel which is the subject of the conversation here). My BMW's 800cc rotax paralell twin does exactly that (4.5L cruising on the highway). Even the 1200cc boxer does that AFAIK.
My 2013 Qashqai 1.6dCi 4x4 weighs exactly 1630kg and uses between 5-6 litres of diesel for every 100km traveled, depending how aggressively I drive it. And no, that's not the value from the car's computer, that's an actual usage.
Just one bit of evidence to the contrary. I have filled the 70 litre tank in a 1.6tdi VW Passat and driven 1400 km with 5 occupants and luggage. This was mainly European motorway driving.
The thing is that the cheats (throwing out unnecessary weight, taping door gaps etc, using super hard notrogen inflated tyres, etc.) would add a constant amount to the fuel consumption, say .2 liter per 10km.
If you keep pushing your engine consumption downwards to the ridiculous levels we see now (<.5 liters 10km), what happens is the "drag cheat" actually becomes a large percentage of the consumption.
Just goes to show that the cars should be designed without large door gaps or outside mirrors (cameras instead) and so on, since they seem to add significantly to the consumptions that that is where the effort should be put.
As a consumer, I really don't care much, I just get consumption data from some independent source such as a magazine or website. Having manufacturers self-test and self-regulate reminds me of the financial industry in 2008. It just won't work.
The lack of good data is really frustrating. The EPA adjusted the formula for mileage a few years ago which made things slightly better but I never come close to hitting the results in my car.
Observed economy is related to personal circumstances, and in my case living at 700 elevation and traveling down close to 0 on a daily basis hurts my scores (along with tire lifetimes, etc). Another thing that bothers me is that performance cars are rated by the same standards, when the people who buy them undoubtedly drive differently than the people buying Toyota Yarises.
Anecdotal reporting online is a joke. You will find endless car forums with people boasting about how they consistently get 25mpg in their V8 sedan. Gimme a break.
What I'd love to see is some service/app that was able to gather real world data from owners of the same type of car in the same area as me along with general stats about their driving style. This would have to be automated to be accurate.
This is the big next step that a lot of people were expecting - where in-depth studies into all of the competitors occurs and it's gradually revealed that this defeat device game has been played by almost everyone in the industry. It'll be interesting to see the repercussions for the automakers, but inevitably this'll end with sweeping legislation changes and reform of the testing protocol and standards.
This is a very good bet. The "defeat device" turns out to be using a feature of the ECU platform provided by the ECU supplier. It would be surprising to find that VW was the only maker to cheat, when the cheating mechanism was available to everyone.
There are some markets, like voting machines, where requiring open, buildable, verifiable code is good practice. Cars might be another.
I was thinking of voting machines as well and think publicly verifiable code and hardware would be a good thing for cars (I don't think it's good enough for large scale elections, but that's another topic).
ps. just reading this in a post from Bruce Schneier[1] that is currently on the frontpage as well[2] which is about cheating software as used by car manufacturers and the IoT that is coming up:
Voting machines could appear to work perfectly --
except during the first Tuesday of November, when it
undetectably switches a few percent of votes from one
party's candidates to another's.
The only problem is that hardware to verify ECU code is an actual car of particular model with equipment to analyse exhaust. Or very precise mathematical model of it which would be much more expensive and would probably require super-computer to run.
It was a response to the large numbers of new models being introduced (each with a couple of engine + transmission combinations), such that the EPA and NHTSA were unable to keep up with the testing load each year.
In hindsight, those agencies should have been staffed better. Additional legislation (which is sure to come, if only so Congressmen can appear to be doing something about the problem) wouldn't have helped, as the cars didn't meet existing laws as it was.
This is not good, but it is much different from the NOx cheat because consumers can easily measure MPG themselves, and do. For that matter it's commonly noted in car magazines that U.S. EPA MPG ratings are lower the E.U. ratings for the same car & drivetrain; I'm not sure the 50% number in the OP would be so high relative to U.S. tests.
It also speaks to the responsibility of the auto press for the NOx issue. They routinely report real-world MPG ratings for cars ("in our driving, we got __ MPG"), but haven't bothered to test real-world emissions despite all the other expensive gear they use to test car performance. Manufacturers and governments should be accurate and honest, but it's also the press that should be routinely verifying their accuracy.
Example of skepticism at the "extremely optimistic European cycle":
Yeah, the European cycle has been known to be a joke for quite some time. The US results are actually quite achievable. Their highway cycle max speed is very low (I think it assumes you don't exceed 55mph), but there's so much slowing and accelerating, even on the highway cycle, that you can easily obtain US highway numbers on an open road if you keep it to say 65 or even 70.
Carmakers, not drivers, are the cause of the problem as obsolete official test results are being manipulated.
Then why does this report compare NEDC numbers with user-submitted real-world consumption? Since car manufacturers have increased power output while keeping NEDC consumption relatively constant, rather than the other way around, you need to drive very carefully to get close to the official numbers. It should be obvious that the more powerful an engine is, the more fuel it can burn in a period of time, if you go full throttle. Which is why they find that BMW and Mercedes deviate more than the average. Dear "Transport & Environment", why do you think do people buy fast cars?
Thank you for the link. I was hoping it would include more detail about the cars. For example which engines and do they have start-stop. About the only thing I saw mentioned but not well accounted for was the automatic gearbox difference.
I have a car with 2.5L turbo engine and I can get from 13.5-28MPG from a tank of gas depending on a number of factors, mainly on how I drive, but also what fuel, how loaded-up the car is, and tires. I suspect that automatics with turbo or supercharged engines with start-stop have the greatest difference in real world v test performance. And yes that is because of how people drive compared to the test.
But it's not the cheating story of VW, continued - that was about nitrogen oxide pollutants which was up to 40 times above what is allowed in the US.
From the report:
> All carmakers have been exploiting ever more flexibilities in the current official tests during 2013 and 2014, but detailed results from Spritmonitor in Germany (Figure 4) show that cars produced by Daimler, PSA and GM exhibit the largest realworld
gaps, around 40%. However, in the past two to three years all major carmakers (with the possible exception of Fiat) have become more adept at using flexibilities in the tests such that all carmakers now have an average gap of 25% or more (as against a maximum gap of only 10% in 2001).
As I understand "Spritmonitor", as a private person, you can record your fuel data (from your receipt) and your odometer to calculate the mileage you can go with your car. No details about the driving behavior that has an impact on how much CO2 is emitted.
I guess that's not the perfect, reliable source - everyone can use the portal and add his favourite car.
But for sure, I'll never reach the official 5.7 l/km with my car ...
"But for sure, I'll never reach the official 5.7 l/km with my car ..." --> are you driving a Russian tank? I drive a 10 year old not particularly efficient Vauxhall (UK) and it is doing ~17 km/l!
That works for CO2, because there is no technology to mitigate CO2 release from combustion. But that isn't the case for particulate matter, carbon monoxide, or nitrogen oxides. You can't put a NOx tax on diesel because the amount of NOx you produce from burning a given quantity of diesel will vary by two orders of magnitude depending on the pollution controls.
Additional fuel taxes are typically not a welcome change among the pubic. I agree that logically this is what should be done, but everyone fills up their gas tank every few hours/days/weeks and sees that price. People only buy new cars every once in a while, and they expect a large purchase price. I think psychologically taxing the vehicle and not the fuel is more of a people pleaser.
And yet, todays weighted average tax for the US is $.4888 per gallon (54.50 for Diesel). Today's national average price of $2.28 puts that at ~21.4%. That probably puts gas up there with one of the most taxed things I buy.
Whole environment damage including the manufacturing should be taxed. Of course this can only be estimated.
Every engine and car produces different environment waste.
For example a Tesla S produces much more carbon in it's production than a gasoline car. There are also other toxins which are produced concerning different type of cars.
A diesel produces NOx but can reduce it with filters.
I think we all should agree that this is the same for every car manufacturer (except electric). Sure, european manufacturers are the target now, but i expect same results from all other manufacturers (including asian and american).
Lab results never represent real street results. How could they? People drive differently and the outcome is based on many aspects that you can't reproduce in lab conditions.
The issue isn't that we can't "represent real street results", the issue is that manufacturers took deliberate steps to alter car behaviour with the intention of obtaining better test results than would be present outside the tests.
But the results they're aiming for are ostensibly based on some measure that represents "real street" results. Otherwise, why the hell do we have these measures in the first place?
The consequences are different however, increased pollution has far reaching consequences, first of all human health. If my neighbour's smartphone has a shorter battery life it doesn't concern me, however if their car (and the cars of million of people around me) pollute more it's definitely my problem.
All these little things add up though. Every device that gets less battery life than expected is taking more power to run. That power likely comes from a non-clean source. Given, it's not on the scale of the automobiles, but dismissing it outright may be a mistake.
Perhaps you did not read the article and responding to the title.
The article points out that 1/3 of improvement in past 3 years to meet regulation requirements was real improvement and 2/3 was just manipulation.
It doesn't matter that people drive cars differently than they are tested in cars, to illustrate it they highlighted that due to those manipulations that difference now can be as high as 50% which is beyond claims that people drive cars differently than when they are tested in labs.
MBP battery issue is a bit complicated, especially when discrete graphics is present due to switching issues with their in-house solution (no Nvidia Optimus for OS X).
MBAs on the hand, I've seen them go past 13 hours easily (~1 year old, WiFi off, low-med brightness, editing documents).
Why? You have just been shown corporate cheat on tests. Why you would ever assume this has something to do with fuel type? I expect Tesla cheat as much as MB or BMW in their "range" test. And if you believe otherwise you are just someone who doesn't learn from his experience.
Tesla's range numbers for the Model S assume about 300Wh/mile average consumption. My average consumption so far over not quite 8,000 miles is 315Wh/mile.
It's hard to cheat in an electric car. Few people care about efficiency directly, but most electric car drivers care deeply about range, and range is just battery capacity multiplied by efficiency. If Tesla were cheating so they could lie about efficiency, Tesla owners would notice pretty much right away that they're not achieving the range they should.
The only practical way for Tesla to cheat would be to ship a larger battery than they say they do, and then fudge the numbers from there. Given the current cost of batteries, this would be an incredibly expensive cheat, and it would be tough to hide from the tinkerers who tear down battery packs to see how they're built.
I have definitely found that electric vehicle companies advertise very sound and realistic figures for their mileage.
My personal case is a Zero motorcycle, but I've heard confirmation from owners of other kinds; the range it gets is more or less exactly what they state for the test conditions (straight level ground, no winds, etc etc). Mine did in fact improve when I adjusted the aerodynamics, but that's another topic.
Tesla have, on a couple of occasions, experienced the opposite: a journalist does a range test and falsifies the result downwards by unrealistic driving conditions. On one occasion they used the car's telemetry to disprove the review.
Top Gear got complaints for doing the same thing to (I think) a Leaf.
But really, Tesla develop cars with high performance characteristics, and then people complain about "unrealistic driving conditions" when people drive them as they are designed?
Tesla could easily program the cars to accelerate moderately and with maximum energy efficiency, but they would't be able to command $80,000 price tags if they did that.
People who spend Tesla, Mercedes, or BMW money on a car, by and large, don't give a shit about economy.
I expect Tesla cheat as much as MB or
BMW in their "range" test.
Many lithium-ion batteries lose capacity with more charge cycles - 20% after 500 charge-discharge cycles would be typical [1] although there are longer-life batteries - so manufacturers who value their reputations design in enough overhead that the battery will still have enough capacity after a few years / when the product reaches the end of its design life.
Personally I'd expect a tesla that had just rolled off the production line to exceed the specified range easily.
Could you perhaps cite any data, any at all? It's not like we don't have a LOT of Tesla owners out there who are obsessively testing this, every day. Do you think they're just all part of the conspiracy?
It is kind of weird that this is surfacing just now. There are magnitudes more VW owners than Tesla. Why have not the consumer studies revealed this a long time ago?
You have to put in a fair amount of effort to monitor the fuel efficiency of a gas (or diesel) car. It's not hard, but you have to keep manual records and do some math.
If an electric car is much less efficient than claimed, you'll notice as soon as you try to drive to the limit of your car's range, because it won't get there.
"Pushing the brake pads fully into the callipers reduces rolling resistance" is apparently one way. That makes me ask the question, why don't we do this already? If it reduces rolling resistance it probably also increases brake-pad life. That'd be a win-win for drivers.
In car braking systems the pedal movement from depressed to pressed corresponds to a very small (<1mm) pad movement. The pad is just touching when the brake when the pedal is not pressed, and pressing the pedal forces the pad and caliper together, increasing friction. Depressing the pedal does not withdraw the pad.
With the brake cylinder fully compressed (as they did for the test), it requires several full pumps of the pedal to bring the pad into contact with the disk. This increases braking distance, which is generally considered a bad thing.
If you make the pedal more sensitive (increase the resulting travel per pedal press) you'll make it harder to apply a precise amount of braking power which doesn't sound like a nice feature. I suppose you could have a more clever system that would move the brake faster until it touches the disc and then behave normally but I suppose that for such a critical system constructors and regulators are very conservative.
There could also be beneficial side effects to having the pad in contact with the disc at all times, such as preventing water/fluids/dirt to coat it. I'm just guessing here.
> If you make the pedal more sensitive (increase the resulting travel per pedal press) you'll make it harder to apply a precise amount of braking power which doesn't sound like a nice feature.
If you've tried hopping in a car from the past few years after driving a much older car you (and you passengers) will have probably noticed this! It's very common in modern cars to have much shorter brake pedal travel, so what would bring you to a gentle stop in an older car will be somewhat more abrupt in a modern car.
This is achieved by having a shorter travel pedal, which is then heavily assisted by the brake servos so it is not horribly heavy to apply. This is nominally for safety's sake, as it reduces the time between seeing a obstacle and the brakes being fully applied. And since all recent cars have anti-lock braking and stability systems it doesn't matter so much if the driver can't control the braking pressure quite as precisely.
> I suppose you could have a more clever system that would move the brake faster until it touches the disc and then behave normally but I suppose that for such a critical system constructors and regulators are very conservative.
Exactly, as I mentioned to the other commenter, it's preferable to have a simple, non powered mechanical system in place to stop the car in the event of bad things happening. Adding extra bits to this system, with the vast R+D cost involved, for marginal increases in fuel economy would be hard to justify for most car manufacturers (especially since the fuel economy saving would benefit the users pockets, not theirs).
It's an interesting one certainly, it sort of comes down to mechanics at the end of the day. In the event of a catastrophic, complete electrical/engine failure, the driver needs to be able to apply enough braking force to stop the car in a sensible distance using their leg muscles. This places an limit on the travel distance of the pads for a full press of the pedal.
Indeed, most cars use a servo that uses vacuum 'pressure' harvested from the engine to assist with braking and reduce the amount of effort the driver needs to expend. However, you can still brake with a non-functioning servo, all be it with a much reduced braking performance.
It's a similar reason why even very modern cars (bar a few, the Infiniti Q50 being one) still use direct mechanical linkages (heavily assisted in many cases) for steering, despite the steering rack, column and rods taking up room and complicating engine bay arrangements. If it all goes really wrong, you need to be able to steer and stop the car.
I think they have direct mechanical linkages because the law says they must. Otherwise many manufacturers would gladly forego all safety issues for profit. A clear public win via govt regulation.
The primary reason is that keeping the pads just in contact with the rotor prevents water from collecting on the rotor surface. Wet rotors can affect braking performance and safety.
As long as the system can quickly return them gently to the rotor surface...
If you change your own brake pads you know that after you finish it can take two whole presses of the brake pedal to get the pads to contact the rotors
The brake pads and jaws get contaminated with dust and the like,making them stick a little. My guess is they get disassembled before test and cleaned perfectly.
When I bought my car (10 years ago) and read reviews, a lot of them say here's what the epa said you'd get for mileage, and heres what we actually got. There is always a difference (maybe 10%). But if it claims 30 mpg and you are getting 17 , I like to think more than few people might notice.
Part of the reason VW was accused of cheating on emissions was it helped mileage.
edit: as pointed out, its 50% more fuel... But still a noticeable difference..
Fair enough.. But still a significant real world difference.
EPA (USA) tests aren't really real world and they don't just drive the cars. Well they drive them on a dyno on a preset pattern (see the picture in the link).
So how many of these cars have turbos? I know the BMWs at least are mostly turbo 4-cylinders.
The whole reason manufacturers are moving to small displacement turbocharged engines over large displacement naturally aspirated engines is because the EPA MPG tests never run the engine in a range where the turbo is doing much. Put the car in the real world and the driver's lead foot makes the turbo kick in, killing fuel economy.
Yes. Turbos are being added to everything, killing the NA engine. The reason is to create a smaller displacement motor which still has the power that drivers expect.
Turbo engines can consume vast amounts of fuel when opened up to full throttle. Modern turbo engines are also very easily remapped for extra power (and consumption) just by changing the boost control.
All the added complexity and cost just to match emissions requirements, which are all negated when the driver 'puts the boot in'.
My thoughts exactly. And I don't think it's just lead footed drivers, the lag on some of these small turbo charged engines is so great that most drivers will feel they have to stamp their foot to the floor just to make the car move.
I think it is a bit unfair to just blame the manufacturers. The legislation could likely be changed to make for a more robust test approach. After all, it is engineers we are talking about here, if they are given a task to optimize an engine's emissions and fuel consumption to a specific drive cycle they will do it. But then of course you have the ethical aspects which I won't go into.
A computer science analogy to this would be if I gave you an uncompressed image and you had to develop a compression algorithm that made the image as small as possible, you could likely come up with a really good solution. But your algorithm most likely wouldn't do as well on any other image.
I think that a feasible solution to this will be to test under a wider range of conditions and add (statistically defined) noise to the testing procedures. The added cost of additional testing would be very small in comparison to the cost of a vehicle development program.
"A computer science analogy to this would be if I gave you an uncompressed image and you had to develop a compression algorithm that made the image as small as possible, you could likely come up with a really good solution. But your algorithm most likely wouldn't do as well on any other image."
That analogy doesn't hold. It's more akin to developing two compression algorithms, one for the general case, and a specific algorithm which is used only when your image is detected for better than the general compression performance use case.
It is entirely fair to blame the manufacturers for this. Gaming emissions results required effort to accomplish, and is completely unethical from an engineering standpoint.
I agree that the analogy doesn't hold for the recent VW debacle (where the calibration was changed during certification testing), but it holds for the industry in large and what has been going on for the past 10-20 years, which is what the paper is about.
The vehicle manufacturers optimize the engine calibration to the drive cycle they are trying to beat. That is why a US-spec BMW has a different engine tune than a Euro-spec BMW for example, the drive cycles are different.
So, does that mean that all those armchair discussions about the merits of ICE and electric cars with "official" mileage numbers thrown about are completely invalid?
A 50% increase in fuel completely changes the cost proposition.
I'm not so sure. Especially for high-end cars, lifetime fuel costs are dwarfed by the car cost. Even in low-end high-mileage cars, both numbers are smaller but the car cost is still probably double the lifetime fuel cost. So maybe across the board we can expect fuel not to be a driving variable in the cost proposition?
This is totally anecdotal, but relevant. I installed the automatic.com car monitoring app/dongle to see how my last car (2013 ford escape ecoboost 2.0L) was performing vs the advertised rates. I drove consistently at a 95-97 score rating for efficiency, and never averaged over 16mpg despite the car being advertised as 23mpg city. Highway driving was different (i got 29.5mpg vs 31mpg advertised). I questioned ford about this and they blamed my city driving on "short trips where the car didn't heat up enough to be efficient". Either way, I was not pleased. My current car (Lexus NX200T 2015) gets 21mpg city 29 hwy within 1-2mpg of what was advertised. My driving patterns haven't changed.
"Miles Per Gallon" is poor metric for reducing consumption.
"Gallons Per Year" would be much better.
Move closer to work, carpool, take public transport, ride a bike, work remotely. Benefits from these things would dwarf any incremental improvements from EPA ratings.
The problem with the environmental problems (currently with VW) and the fuel consumption is, that particularly in the EU, the governments for years (if not decades) turned a totally blind eye on the car manufacturers.
The problems with the emission measuring and also fuel measuring was known for long now and in the EU, many wanted to change the measuring methods -- but for example the German government did always block such advances.
In my opinion, not only the car manufactures are guilty, but even more the politicians that made it very easy for them to cheat on us all. The additional expenses (at the gas station and with the bad air) carry the consumers.
Also rules that are in conflict. To get good mileage and corresponding low CO2 emissions, you need ultra lean mixtures. Alas, ultra lean mixtures produce more NOx.
You want low NOx emissions, you need richer mixtures, and thus higher fuel consumption and higher CO2 emissions.
> Isn't that where catalytic converters come in though?
Diesel exhaust is too oxygen-rich for the cat to effectively catalyze the NOx. That's why recent passenger car diesel systems have a Diesel Exhaust Fluid system.
Here is one. My Porsche has a display which tells you the MPG. However the car display is consistently between 1 and 2 mpg better than what I calculate after filling the tank and doing the math. And I repeat it's consistently worse than the display which calculates the mgp per tankful which is probably what most people rely on. I've been meaning to bring this up with the dealer but haven't so far. This is in addition to not coming anywhere near to the stated MPG and with conservative driving (non sport mode ..)
Yeah, mileage computers in cars are known for being a bit optimistic. It's not hard to beat the EPA highway number for your car. Put it on the highway, cruise at 65mph, done. The EPA test cycle doesn't even exceed 55mph, but it has quite a bit of slowing and speeding up, so you can beat it with a consistent cruise a good bit over their 55mph number.
A partial reason for this is that the speedometers have to be optimistic by law (depending on jurisdiction, but I think this is the case most everywhere.
When your speedometer shows 100 km/h, it is permitted that true speed is 90 km/h, but it is not permitted that the true speed is 101 km/h. And the same variance applies to odometer, of course.
Things like tyre wear and pressure have a noticeable impact on what both meters show, and manufactures have to stay on the safe side, by law.
This is true -- my understanding is that Germany actually requires they never read low EVEN IF FITTED WITH THE WRONG SIZE TIRES which is sort of insane.
That said, I believe the odometers are typically bang on, which would mean the mileage calculation should be accurate. Or could be, if they wanted it to be.
I wonder to what degree this is due to Europe's use, as I understand it, of an absurdly optimistic testing procedure (NEDC) which does not reflect real-world driving patterns.
I never pay attention to fuel consumption figures as they have never represented reality in my case. My current Mercedes has an official rating of 40mpg, but I never get that out of it unless I literally sit at 55mph on a flat motorway and never change speed (impossible in the UK). Some journeys I go as low as 19mpg when it's driven as it's meant to be. All the Vauxhalls I had before were the same.
Reminds of the cycling world. Boundaries are pushed with doping and in order to stay competitive, after a while everyone is doping until the whole thing collapses.
The same thing goes for bodybuilding, anyone has another example?
One of the Marxist critiques of capitalism is that if an employer wants to do certain good things (like treat his workers well, pay more salaries than the bare minimum, take care of the environment and so on) he can't do that because that will raise the price of whatever he is selling and he would be outcompeted by his less altruistic rivals and go bankrupt. So every business owner has to be a bit of a psychopath to survive.
Cliffbar lavishes perks on their employees and they seem to get by selling commodity food products. The problem is when the people at the top take everything for themselves and leave nothing behind. Issuing public stock induces the worst of this sort of behavior due to the need to market the company to investors on the single line item of profitability.
I monitor my mileage by simply resetting my trip meter on a fillup and looking at how much went into the car and dividing. The largest source of error naturally is that not all pumps are gaurenteed to fill to the same hieght and some places may be on a hill etc.
Obviously this is only as good as the way I drive (or my wife) and is heavily dependent upon if I hit traffic, mostly drive in the city or go on a road trip.
It really is an interesting thing to keep track of.
One problem with the report is that real-world driving styles might be linked to the type of car. So, small cars might perhaps be more likely used for short commutes, whereas larger cars could tend to have longer motorway journeys. One driving style is likely to be closer to the standard tests than the other. So, even if one car seems to perform worse, it could just be because of the average driving of that car.
No. The emissions test has to pick a certain kind of driving style. It can't emulate them all.
The report, on the other hand, could try to compare like-for-like. For example, they could give separate results for high-mileage drivers and low-mileage drivers. Or split the results by average speed, to try and isolate long-distance motorway drivers from short commutes.
It's worth mentioning on the other hand that -- based on my experience -- the VW Diesels currently being recalled for cheating their NOx tests consume significantly less fuel than they are rated to.
My 2009 Jetta was rated at 29 city, 33 combined and 40 highway . Based on my fuel records, I got 33 city, 36-38 combined and 50 highway.
That means it out-performed the EPA estimates by 25% highway, 12% combined and 14% city.
well it really depends on how you drive as well. I have had only one car in the last twenty or so years where I could not consistently beat the EPA ratings. Plus throw in that most ares have ethanol formulations and that will lower your mileage.
Far too many race from light to light, keep on the gas even when going downhill and over the limit, brake late and even run with tires under inflated.
anecdotal, my current car a s28 Z4 uses a four cylinder turbo. 23/34 I think are the official ratings, I have yet to average a tank under 30 and did 40 on pure highway at speeds over 70. Granted its a manual which lets me abuse the rev range a bit more than the 8 speed auto offered but its simply down to learning to drive your car within its best performance parameters. I still have fun, run it up fast, but mostly just drive relaxed.
Does it mean that some cars are not performing to what companies claim. I am quite sure they aren't. I could not get a 2013 Mustang V6 above its EPA AVG to save my life.
The conclusions in the article are bullshit. There are a number of possible explanations.
1. offical does not reflect real world.
2. defeat devices.
If every car manufacturer is using defeat devices it really shows how poorly EPA requirements have worked. Blame car manufacturers, sure, but they're supposed to be selfish. That's how economics works.
Didn't I read somewhere or maybe it was John Oliver on Last Week Tonight that corporations in the USA report their own MPG to the government on an "honor system" because congress won't fund proper testing by the government.
So much for government protecting the people from corporations and their sole quest for profit.
They do, but the EPA also spot tests cars, and the system works pretty well. They recently fined Hyundai for not matching their quoted numbers. The EPA test cycle is not particularly representative of real-world driving, but it's far better than the European tests are, which easily allow you to game the system.
Seems like the system works quite well here in the US, even if you might quibble with their idea of a city and highway drive cycle.
It's called "real world driving". Look, this is no different from Tesla claiming a 280 miles range that nobody can achieve. Not saying it is right. What I am saying is: We need better tests.
It's not actually very hard to achieve rated range in a Tesla. You might need to refrain from flooring it at every opportunity and you might want to cut down from going 10MPH over the speed limit, but it's not a challenge.
You missed my point, which is that it's easy to achieve rated range in a Tesla with real-world driving.
I have not taken care at all to drive my Model S in an efficient manner, and I still have an average of 315Wh/mile over about 8,000 miles of driving so far, where 300Wh/mile is rated efficiency.
The bit if data you are leaving out is the nature of the terrain and traffic you experience. I am not disputing your numbers at all, I am simply saying more data is needed in order to fully evaluate it.
Beyond that, the truth is you cannot get the rated range because that would mean draining the batteries to zero. Real range anxiety, depending on where you drive, starts to come in somewhere below 50 miles from fully drained.
You also have a difference in performance between summer and winter driving. If you have a short daily commute, the combination of the "off" state drain on the battery overnight and the car warming or cooling the battery pack while parked in cold or hot weather can have an impact on available range and performance.
BTW, I am NOT saying any of this is bad. I am simply saying these are realities of the contrast between advertised specifications and performance under real life conditions.
That's fair. I think we can say there are two kinds of "do you achieve these numbers in the real world?" One being whether you can do so without completely artificial conditions, and one being whether you always get the given numbers. It seems we're just talking about different ones there.
How is that possible with the current gas prices ? I can't even comprehend that. I would have thought gas mileage would have been a very important issue so that entire countries can save money.
I have one of those cars and it actually gets more mpg than what the sticker says, not sure how it would be possible to be 50% off from that, people would figure that out pretty quickly.
This is Chernobyl for automotive, Elon Musk wet dream and the chance to make electric cars appealing to the general public at last. Great uncle Charles Darwin having a good laugh too, evolutionism at its best.
A reckoning is coming.
source: see page 13, here
http://www.transportenvironment.org/sites/te/files/publicati...