This article gets the concept slightly wrong.The compressed air becomes very cold air when it expands rapidly in the intake.
Colder air is more dense and therefore carries more oxygen. More oxygen allows more fuel, which allows more power.
Here's a better explanation in a single paragraph on the company's website:
> The end result of these expansion processes is that the charge air temperature entering an engine is dramatically lower than can be achieved with conventional MAP increasing technologies (supercharging and/or turbocharging with after-cooling). Hence very high charge densities can be attained at relatively low MAP levels.
The goal is to increase the amount of air going into the engine by making it very cold and dense, not by pressurizing it like a supercharger. Low MAP means low manifold absolute pressure. In other words, it's not boost like a turbo or supercharger.
EDIT: It looks like the website is also unclear. There is some mention of a secondary valve shutting off the intake valve to prevent air leaking out from the air filter.
Their website is strangely unclear. This isn't mentioned in the "Theory of Operation" section but does get mentioned later as an "isolation valve"
WWII era planes such as the Bf109 injected water and methanol into the supercharger to allow higher boost, side effect of that was charge cooling (and engine cooling).
My understanding is that the water is mixed with the fuel to help atomize the fuel as it's being sprayed out of the injector. If the fuel is atomized, it burns all at once which increases efficiency. I doubt a little bit of water is going to cool any meaningful amount of air.
It is boost pressure in the sense that the air going into the intake manifold is above ambient pressure. It isn't like nitrous where air still comes in the intake, with compressed air systems there is a valve that's closed to prevent the engine from ingesting ambient air, it runs entirely on the compressed air.
I know what the article says, but the author seems to misunderstand how the system works.
The systems has regulators that step the air pressure down from thousands of PSI in the tank to a much smaller, regulated number at the nozzle that gets sprayed into the intake.
From the source company that sells the system:
> The very low temperature medium pressure air stream is then throttle one more time in the Electronic Pressure Regulator before being discharged into the engine air intake tract. The throttling effect that occurs here is small compared to that which occurs at the Mechanical Pressure regulator but, similar in nature.
The tuner can adjust the pressure that is being discharged into the intake tract, but that's not equivalent to the pressure in the manifold.
The system works by having the air expand rapidly in the intake, causing a rapid cooling effect.
I guess in some ways that matter they are different. I’m not super familiar with turbo/superchargers, but aren’t they driven by belts in the engine or linkages? I would think that turbo lag shouldn’t happen with a compressed air system, for example.
But to your point, I agree. Once the boost is achieved, the effects of the boost occur, because they aren’t really related to the source of the boost or how it is implemented. However, systems that use the engine for power like turbos may lose efficiency compared to compressed gas at the same boost level, depending on how much the gas system weighs compared to your turbo. It’s an interesting idea, especially for drag racing.
I guess the cooling alone cannot reach the density (and oxygen amount) necessary for the designed power output.
Yes, they put in the energy to compress the air 'offline' and then have that free to propel the vehicle.
The cooling of the charge also improves the efficiency, the useful energy output is proportional to the temperature difference before and after the combustion.
A high capacity intercooler would be an interesting experiment also in utility vehicles.
Colder air is more dense and therefore carries more oxygen. More oxygen allows more fuel, which allows more power.
Here's a better explanation in a single paragraph on the company's website:
> The end result of these expansion processes is that the charge air temperature entering an engine is dramatically lower than can be achieved with conventional MAP increasing technologies (supercharging and/or turbocharging with after-cooling). Hence very high charge densities can be attained at relatively low MAP levels.
The goal is to increase the amount of air going into the engine by making it very cold and dense, not by pressurizing it like a supercharger. Low MAP means low manifold absolute pressure. In other words, it's not boost like a turbo or supercharger.
EDIT: It looks like the website is also unclear. There is some mention of a secondary valve shutting off the intake valve to prevent air leaking out from the air filter.
Their website is strangely unclear. This isn't mentioned in the "Theory of Operation" section but does get mentioned later as an "isolation valve"
See here: https://casupercharging.com/tech/#system-overview