[qikInNdOutReply]

Wrap the combustion engine with a heatpump to a small steam engine?

[osigurdson]

It isn't precisely "wrapped", but this is essentially how all natural gas fired generation facilities work.

https://en.wikipedia.org/wiki/Combined_cycle_power_plant

[greesil]

I think the parent is referring to harvesting some of the waste heat

[Sohcahtoa82]

The added weight and complexity would probably negate any benefit gained.