Internal Combustion of car engine is a thermodynamically reversible process where energy from the combustion of a fuel is used to do work.
It burns fuel in the form of diesel, which has a lower energy content than gasoline or other fuels.
Diesel engines work by burning a fuel to create steam, which moves a piston back and forth inside of the cylinder. The pistons compress air before entering the cylinders, creating enough pressure for them to move through and out again.