Today’s invention is a modification to the engine of a snowmobile.
Given that the efficiency of any engine is increased by lowering the temperature of its exhaust, a vehicle which travels almost exclusively on snow has the great advantage of access to an effectively infinite heat sink.
The exhaust pipe from a petrol or diesel snowmobile would be redesigned to incorporate a springloaded metal plate protruding downwards from the engine.
This would be free to pivot to accommodate the undulations of the snow surface with which it would be pressed into contact. Its temperature would thus be several degrees below that of the ambient air.
A few extra % in fuel efficiency would be attainable which, in the frozen northlands, could represent a significant saving on operating costs.