[queuebert]

I'd like to add that ICEs need to run hot to minimize cylinder wall heat losses and allow more of the explosion to be converted into work instead of heat, although too hot and they break of course. Ideally the engine block would be at the same temperature as the combustion temperature, but we don't have the materials to achieve that yet.

[jacquesm]

There have been some experiments with uncooled diesels that almost made it.