cryo-ICE hybrid
 

Hey just had an idea come across my mind. How practical would it be to have a small Liquid nitrogen engine that uses internal combustion engine waste heat to run in a hybrid setup?

Since the liquid nitrogen engine is essentially a cooling source for the ICE you could even do a radiator delete yielding weight reduction (maybe not net though). You could insulate the engine bay so it could work in wintertime too.

I could also see the LN2 engine perhaps charging a gas-electric hybrid battery. LN2 is about 6 cents (US) per liter in truckload quantities making it pretty cheap. Idk if this is offset by its low energy density... even about 30 times less energy density than gasoline that comes to about $1.80 to get the same potential energy (efficiency may be a problem).

Seems like an obvious synergistic fit to me, but I haven't seen any examples of this online yet. would too much cooling from the ln2 reduct the ICE efficiency? Am I ignoring basic laws of thermodynamics here? Thoughts?

The super cooling of the engine would hurt efficiency and you would have to watch for the change in volume from the expansion of the liquid to gas.

It would also be range limited by the nitrogen, you'd have a real nightmare on your hands when you ran out of coolant, but one idea to save this would be that if you had a cryogenic primary fuel such as natural gas, you could use a radiator coil and a fan as the gas travels to the injection point (or carb whichever fuel delivery mechanism you prefer) and you have AC when you need it. just have to have something to keep the coils from icing over unacceptably.