Quote:
Originally Posted by ksa8907
Ideally, assuming this idea can work, i think anticipating the spring compression and then increasing the compression ratio back up to what is common on todays engines could mean big power numbers. You would effectively be getting a longer stroke out of any given engine.
Another effect, as the piston is decelerating toward bdc on the intake stroke, it may also compress the spring at higher engine speeds allowing for a larger effective displacement than static.
...maybe not since the spring would definitely be compressed on tdc.
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The compression ratio shouldn't change. The spring should be stiff enough to only start compressing after fuel burning has well progressed. I don't see the need to increase power in today's engines, only reduce wasted heat(increase efficiency) to get more energy to the wheels and less to the exhaust and radiator.
From what I have learned about engines you need a certain compression to get the air/ air fuel mixture hot enough. After that it will ignite(by itself or sparkplug) and burn by itself. After igniting it releases heat which raises temps and pressure more. At a certain point the combustion will be hot enough so there is no combustion gain raising the temps more.
The high temps get absorbed by the cylinder walls, head and piston. Which is waste heat to radiator eventually. If the peak pressure and thus temps is lower, the difference between engine temp and combustion temps mean less heat will get absorbed by engine.
Also T Vago:
The spring should be stiff enough not to compress at BDC, only closer to combustion peaks. If it does compress at BDC I think the engine will have problems during combustion to burn the fuel. Someone who knows how to work these things out will have to enlighten us.