thinking outside the box , what 99% of arent capable of , we are much alike man but in the world alot has been thought of and tried and tried again .

thats why we have nitrous oxide , similar to were the idea of a large supply of air would morph into is having liquid oxygen or to nitrous oxide where it also helps the combustion cycle.

i know your goal isnt a time or a power number rather something that performs like nothing else , im going to see where this goes and keep my mind open and processing some ideas .

 

You already have this low compression engine why not pump hotter air in with even lower compression so the fuel is nearly at the point of combusting with just the compression of the piston. So many people think that heat is bad for a motor, but only in the way it is precevied. Heat = Energy, run less compression get the heat from the exhaust and maybe a grid heater too if needed, to get the intake temps way up like 300 degrees, add in a little compression with a final temp prior to spark at 450* and make more power by waisting less on the compression stroke.

 

Fantasize away buddy, without it we would never progress. However, if your interested in going that route I would suggest either a 2cylinder diesel or somekinda of electric regenerating hybrid motor. Or hell, there's a million better ideas than the two i've thrown out there.
The gas turbine would consume copious amounts of fuel, however they are known as being one of the more efficient engines out there (do not read fuel efficient, just efficient as in having less losses, parasitic, heat, etc... than other mechanical engines). With some modification to the burner cans you might be able to turn a gas turbine which is constantly suppling fuel into a sort of pulse jet engine which uses intermittent burst of combustion, similar to reciprocating piston engines. But I'm not sure if the burner cans can support the violence of intermittent bursts.


I might look into it eventually, I know a few places/people I can turn to for help with it who've done similar things when the time comes. Just right now I'm focus'd on finishing my truck.

Mercedes invented a engine called the Diesel-Otto a few years ago that essentially turned a gas engine into a diesel engine when cruising. It would tighten up compression in the motor by lifting the crankshaft up. Kinda trick how they did it as the cranks was actually suspended on a chain of some sort. So during stop and go the engine was a typical gas engine and while cruising the compression would raise half a dozen points and the spark plugs would turn off and the injection sequence would alter to allow for compression ingition. Not sure where they ever went with that idea.

 

Not what Im getting at,

From wikipedia: A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air-fuel mixture due to its higher thermal efficiency. High ratios place the available oxygen and fuel molecules into a reduced space along with the adiabatic heat of compression–causing better mixing and evaporation of the fuel droplets. Thus they allow increased power at the moment of ignition and the extraction of more useful work from that power by expanding the hot gas to a greater degree.

Now instead of using compression to heat the air, use a turbo or supercharger and a heat exchanger in the exhust.

Lower compression will need the boost to adequately fill the cylinders, and heat the incoming air so that after full compression the cylinder temp is just under the flash point. The gain... Imagine for example your crank had a 1" stroke, with a 2:1 compression ratio. How much less power would be required to compress 7-10 psi incoming from the turbo at 200*. How much fuel could that save? All that heat in the manifolds is just wasted energy.

Now Im no engineer, but this makes sense to me, wanna be the guinea pig?

 

I like where your thinking, but that motor wouldn't be able to get out of it's own way let alone make enough to run the accesories IMO.
Two things:

HEAT:
Heat isn't just percieved as bad, it is bad because cold air is denser and reacts more violently during combustion(for reasons I've read but have since forgotten and can only speculate on right now). The hotter the air, the less dense it is meaning there is less oxygen mass per given volume. If you pre-heat the air (300+ degrees) prior to filling the cylinders your gonna be putting in miniscule amounts of oxygen when compared to air that is 250 degree's cooler. (I would do the math but I don't know the forumulas off the top of my head) A motor is a glorified air pump, if you remove the air from the equation your nullifying the motor's purpose.


COMPRESSION:
2) High compression is essential to efficient mixing and evaporation of the fuel droplets. Removing that from the equation will produce a dud of a motor, and I would actually think no chemical burn would take place at 2:1 CR with 300 degree temps. Only reason we look to lower CR on our boosted applications is because of the limitations of the fuel we used. If we weren't required to use crappy pump gas we would all ideally be bumping up the compression rather than lowering it.

 

A little bit of boost would help with the mixing and high intake temps will evaporate the fuel.

My theory of a motor and your actual motor both have the same goal, get the fuel/air mix in the combustion as close to the flash point with out going over to get the most efficient burn. Your motor uses compression to take the mixture up to the flash point. Mine would use preheating. While I agree that each cylinder would make less power than yours mine motor wont be using very much energy to compress the next piston in line.

If I had the money and the know-how I would have tried this already.

 

yes turbines use more fuel per hp produced, but they make it at massive rpms. the apu in an apache makes about 90 hp at 23,000 rpm. if you wanted to use that on a car, you'd need to gear it down considerably. gear it down 4:1 and you'd be at 5750 rpm and, not counting frictional losses, you'd be seeing 360hp. so it might be burning lots of fuel for 90 hp, but by the time you gear it down it just might be worth it fuel wise. and the thing is light enough that two people can pick it up. i've thought about doing it too lol. it'd be a definite alternative to a heavy small block in my opinion. however, lacking funds and experience this is just an idea

 

Gearing it down would not increase power.

 

engine horsepower no, but the amount of power you can actually use would be much higher

 

You mean torque you can actually use...gearing it down does multiply that.