Efficent engines

hey /sci, what's the most efficent engine you guys know of.  for me, it's the sterling and the turbine, both coming in near 50% efficent.  anything better?

Um, ideally a high temp heat bath, slightly lower temp heat sink Carnot Engline.

Efficiency = 1 - (Th / Tc)

I think that's cheating a little, seeing as it takes energy to store the energy you need for it. I think a solar radiation and heat powerred electric ultra light train is the most efficient engine you can get. The infrastructure is expensive, but you have 0 fuel costs which is a luxury in some times and places. For instance the future, when crude oil derived diesel is more expensive than plant oil diesel.

I think we should use the fossil fuels we have now to prepare for when we don't have them.

we're talking about the most efficient engine here, that is, converts as much of the energy input to movement, and as solar panels have like 30% max efficeincy, they ain't make a very efficient component.

first year physics: Carnot Engine is the most efficient engine. An engine that has 100% efficiency does no work at all.

>>5
That's sorta what I posted as >>2
Efficiency of a Carnot engine = 1 only if hot and cold sink are the same temperature, in which case the engine doesn't really do anything... at all.

But yeah, 1st year physics here. I wish people wouldn't dump their easy homework here...