I think we are now all on the same page.

A gasoline engine is, after all, only one form of a "heat engine."

http://www.taftan.com/thermodynamics/HENGINE.HTM

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heaeng.html

No matter what cycle it uses, Carnot, Otto, Rankin, etc. a heat engine must conform to the laws of physics and thermodynamics.

It is tough to convert heat into mechanical energy. The early attempts used external combustion.

http://inventors.about.com/library/inventors/blsteamengine.htm

Then came internal combustion.

http://inventors.about.com/library/weekly/aacarsgasa.htm

I see a promising future for the fuel cell, which converts the energy contained in hydrogen atoms directly into electricity, which can be used to produce mechanical energy using electric motors. The hydrogen combines with oxygen, and the exhaust is mostly warm water.

http://science.howstuffworks.com/fuel-cell1.htm

Best Regards,
Jim