Compressed-air kinetic energy recovery system?

[xpensive]

You did indeed Ciro, mea culpa.

Good to see you back, you have been dearly missed around this corner of the cyber-universe.

[Desertrunner]

Air tank Made of Carbon fibre can be extremely light also as I see it if you were smart the tank would be a rigid part of the chassis structure so as to offset any weight gain.
If the pump sending air was anchored to the engine crank it would minimize weight increase.
Last point is that you need a variable pump so that at low pressure it will pump a lot more air and at high pressure it can still fill the tank.
Bit of smart design could mean that the same pump operates as a motor as well so not only do you have te ability to Supercharge the combustion chamber but you can also increase power with a different motor.
The maximum amount of air (energy) being stored is only limited by the strength of the pump and tank.

Tony

[neilbah]

http://www.autocar.co.uk/car-news/genev ... ir-concept

[riff_raff]

Where did you get that idea, 300 psi is just 20 bar, while MDI uses 300 bar with a tank tested for 450.

My response was about using the engine cylinders as a compression device. Unless you were to employ some sort of variable CR system or some porting system that allowed staged compression between multiple cylinders, then you would be limited to the discharge pressure that could be achieved with the engines existing CR.

As for using crank-driven devices to compress air to very high pressures (ie. 300 bar), this is quite difficult to do in practice. Due to the high gas temperatures produced by the compression process, compressing air to 300 bar would require several stages with cooling between each stage.

Of course, it would be possible to recover significant amounts of energy by using engine exhaust to heat the compressed airflow just prior to passing through the expansion device.

[Mikey_s]

Air tank Made of Carbon fibre can be extremely light also as I see it if you were smart the tank would be a rigid part of the chassis structure so as to offset any weight gain.
If the pump sending air was anchored to the engine crank it would minimize weight increase.
Last point is that you need a variable pump so that at low pressure it will pump a lot more air and at high pressure it can still fill the tank.
Bit of smart design could mean that the same pump operates as a motor as well so not only do you have te ability to Supercharge the combustion chamber but you can also increase power with a different motor.
The maximum amount of air (energy) being stored is only limited by the strength of the pump and tank.

Tony

My 2 c on this is that the chassis is made as strong and as light as it needs to be and no more. Furthermore, it is also made as small as it needs to be. For a usable amount of energy to be stored, the volume of air required would be substantial and the pressure required would be immense. To use the chassis as a pressure vessel would mean increasing the strength of the structure to accommodate the required pressure, plus a significant safety margin for a crash event; Imagine the carnage if the vessel was punctured in an accident. As with all of the recoverable energy storage devices there are safety issues to be considered.

The advantage of electricity is that, although the batteries/capacitors are heavy, the car does not get heavier when the battery is charged (the electrons only move from one place to another). Storing energy as compressed air would mean the car getting heavier and lighter as the energy was stored and released, changing the balance of the car. The rate of energy release would also diminish as the pressure dropped.

[WhiteBlue]

The real problem is the low cycle efficiency if you do not handle the heating and cooling. And if you do so the weight of the additional equipment is prohibitive.

[tuj]

Instead of trying to store enough air volume to support the engine's breathing requirements, why not use the compressed air to dump into the exhaust and spool up the turbo? The hot exhaust would handle heating the decompressing air.

The tank for the air could be build inside the chassis, especially if the chassis is a double-walled affair that is air-tight.