Is Compressed Air the Key to Fuel Economy Savings?

I'll believe it when I see it; on the road collecting mileage data. But I must congratulate Mr. Scuderi on his accomplishment in raising $65 million. That number will pay a lot of salaries and hopefully their recipients will produce somethiing useful. But even if they don't at least it helps the employment situation. ............Ed Weldon

The Ad should have shown a Christmas tree that lights itself.

This has been floating around for a while. I think the main expertise here is marketing. Compressed air power would be really cool if it weren't for that pesky thing called thermodynamics.

The claim is not justified in the way this is explained at least:

To compress the air in the 1st place, requires energy E1

To use this compressed air to recover the energy will only recover E1/2 (half of it at best efficiency).

Simple: There is no increase in energy produced to the output of the engine! At best you will keep the original efficiency without this contraption.

the Only avenue I can see to improvement will have to be that if this process IMPROVES the combustion efficiency enough to upset the losses involved with this addition.... More details are required in that direction to have any opinion towards a realised improvement.

Isn't air compression driven directly from the engine prior to intermixture with fuel entering the cylinders essentially what a supercharger does.

Yes, the question is what is the most efficient air pump?

A supercharger takes energy from the exhaust gases that would otherwise be wasted to the atmo. While the extra contraption will need extra power to be driven and the exhaust still goes wasted (?). Something else most come into the design to make it worthwhile discussing.

You're describing a turbocharger

a supercharger is belt, shaft or gear driven & generally a lobe pump [positive displacement]

Yes it appears he misinterpreted between a turbocharger and a supercharger.

For clarification, the compression in the first cylinder comes directly from the drive shaft transfer from the second cylinder power to the first. A super charger is driven directly from the drive power of the engine. A turbo charger is driven from the exhaust from the engine, not from direct enginer produced power. Tyhe difference here between supercharger and the precylinder compression is that you install a external connection to transfer the power from the drive shaft of the motor, rather than being built directly into the drive shaft.

Thanks for the clarification.

But In any case, if a supercharger is used, then the reason for this is to increase the engine output horsepower and not to significantly improve its fuel consumption efficiency if any. Correct?

ideally if you increase the pressure in the cylinder {& horsepower}, you can decrease the displacement needed & fuel consumed

the main difference between the 2 systems is the use of a tank to store some of the excess capacity, for boost when you are starting from a stop

I didn't see any specifics about the capacity of the storage?

Well, as I see it, the system proposed is almos the same as a supercharger, more complicated and built into the engine from the start, taking its drivr from the crank shaft directly.

In this case and similar, you are taking extra power from the engine (the result of the combustion), to compress air and then re-using it. This exercise is by itself not efficient (< 50%), like any piston air compressor. therefore, we are not increasing the power output at the shaft with the same fuel consumption as before the supercharger (for the sake of clarity and simplification). rather, we will have less output. The only immediate benefit is to be able to increase the amount of fuel that can be mixed and used for the same equivalent engine cylinder capacity.

Now, unless what has been proposed is not clear and there is some design magic not revealed, the system proposed will not increase any efficiency by reducing the fuel consumpton for the same output power on a comparable convemtinal engine.

Correct?

Garthh,

Ideally if you increase the pressure in the cylinder {& horsepower}, you can decrease the displacement needed & fuel consumed

The word "ideally" may be your way out. I am referring to the words 'and fuel consumed'.

Surely, increasing the mep (mean effective pressure) allows a reduction in displacement. But would this necessarily reduce fuel, in other words increase efficiency? That I am not sure of.

Could you have some explanation to that effect?

Could you have some explanation to that effect?

I think you just did :D

"If you use 'horses', you have to feed 'em".

Wise old saying from Dr Wally.

Small engine working hard, or big engine working easy, same hp on the dyno, same, near as dammit, fuel usage. I won't go into pumping, friction, fluid dydnamics, heat rejection, 'windage' et al, losses.

cheers,

Stu.

Interesting concept. Some questions, or points to ponder:

1) How is it throttled? Possibly by restricting the flow of air between the cylinders. Simply increasing or decreasing amount of fuel provided is not likely to be acceptable due to combustion and emissions issues. Could also simply decrease the pressure to reduce the amount of air that is pushed into the 2nd cylinder.

2) Why bother with the complexities of the first cylinder & piston? Would not a supercharger be more efficient at providing sufficient airflow and pressure?

3) Does the 2nd cylinder compress the air further, or is the piston at or near the top of the upstroke? The air being introduced into the 2nd cylinder already compressed would be a significant difference from traditional engines. But it still takes a certain amount of energy to compress a certain volume of air to a certain pressure, regardless of whether the 1st or 2nd cylinder (or supercharger) does it. Not much to be gained by reducing the pumping losses on the induction side.

4) Efficiency is increased by getting more power out of the same amount of fuel. What is it about the arrangement described that allows more of the heat released during combustion to be converted to mechanical energy?

5) What is the expansion ratio of the 2nd cylinder? The more the combustion gases are allowed to expand before being exhausted, the more energy can be converted from heat to kinetic. One of the key features may be the ability to make the compression and expansion ratios independent of one another. In other words, 1st cylinder is optimized (bore/stroke, piston dome shape, porting, timing) to compress efficiently, and 2nd cylinder is optimized for maximum energy extraction.

maybe when the car is stop on the traffic lights then it may be efficient. But i would also/rather see the heat from the engien used to make Stirling engine generation an electricity.

http://www.youtube.com/watch?v=ICX3KPiPhcI&feature=player_embedded#