Is it strictly true that an engine will be more efficient if operating in a hotter environment... e.g. your car is more efficient in the summer than the winter? Just going through thermo 1, not a HW question, but it just seems to be true to me because the simple newton's law of cooling says there will be less heat transfer and thermo says therefore there is more work output / less loss associated with the cycle. Of course this doesn't take into account efficiency of fuel (for your car). I have no idea how it would affect combustion. Maybe next semester in chem I'll get a better idea ;) Probably a simple question, but I'm curious :) Thanks.