Why not use engine heat as an auxiliary power source instead waste energy to be disposed of? Instead of adding coolant to the radiator water, let it boil. Then a thermostatic control would convert some of the cylinders from gasoline to steam power untill the steam preassure goes down and the control returns the cylinders to gas power.
-- tonybe, Dec 03 2009

additionally there is a bit of a thermodynamics problem here: If we have a pressurized boiler instead of engine coolant can the engine be effectively cold enough to have proper gasoline combustion but hot enough to be an efficient producer of steam? Apparently a diesel can do this but it works best if:

A: the engine is designed for direct injection of water B: the engine turns very slowly C: The engine is compression ignition D: The engine has substantial mass E: The engine is not otherwise cooled

Thus we can have a hybrid engine that alternates between the direct injection of diesel and the direct injection of water. Water is boiled in the cylinder head converting heat into pressure and diesel is burned providing heat and pressure.

This works well in applications where a large stationary engine drives a steady load and where a substantial supply of fresh water is always available. I suppose that in some applications the water may be condensed,filtered , then recycled, but it seems unlikely.
-- WcW, Dec 03 2009


Ideally, it's a dual-circuit system.

The internal combustion engine is cooled by a primary pressurized, sealed circuit operating at above 100C - the coolant doesn't have to be water, NaK would be good.

This circuit dumps its heat into a boiler which produces steam for a piston or turbine engine.

As to energetic efficiency, do the math.
-- 8th of 7, Dec 03 2009


seems like a bun for a stationary engine, a bone for a vehicle engine where the weight penalty would likely outweigh the benefits. I don't see why the water could not be easily recycled on a stationary setup. Perhaps instead of using a cylinder/piston setup idealized for petroleum combustion, a turbine could be used.

I like this one!
-- rocdoc, Dec 03 2009


a simple search for "diesel steam hybrid" brings up literally dozens of designs. Some are even more frilly and exciting than the one above. It really isn't a new idea.
-- WcW, Dec 04 2009



random, halfbakery