If an automobile had a 100% efficient engine a)would it be warm to the touch?

Question

b)would its exhaust heat the surrounding air? c)would it vibrate?Would any of its fuel go unused?Explain.

Answer 1

No, no, no and no. If it's a combustion engine, all the chemical energy of the fuel would be converted to mechanical and/or electrical energy usable for automobile propulsion and accessories like radio, AC/heat, power-assisted stuff. No heat output from the engine block or the exhaust, no useless vibration and no fuel wasted. In fact no exhaust since that moving gas is not efficiently convertible to vehicle motion. No sound output. No cooling system. Totally frictionless. You couldn't tell it was running unless the vehicle were moving. Etc., etc. Of course, that 100% efficiency is physically unrealizable by the laws of thermodynamics, but an all electric powered car would (and does) come close. With those cars the main inefficiencies occur further up the energy chain, if the source electricity is generated by combustion engines.

Answer 2

hi don't be attentive to what are you tying to to on the motor vehicle?,yet once you basically ask those questions ok.if your engine runs for 20 min then has reached temp 80 c that's warm cant touch.comparable exhaust.

Answer 3

Such an engine is an impossibility.