|
Using the spark plug wires to signal the water injection might be a good idea because the water will not boil instantaneously, like advancing timing for combustion it may prove advantages to start the process just before top dead center. I wouldn't worry about needing a diesel engine, the steam pressure will be lower than typical combustion pressure.
Something I didn't mention is that a part of the 35% of the wasted exhaust energy is pressure, what part I don't know. But if its going to be expand a second time you might as well expand it fully. So maybe you should bore and stroke the two middle cylinders to allow for more expansion of the exhaust and the steam.
As for the steam compression stroke I don't think it works the same as what your thinking (assuming I know what your thinking). Compressing the steam isn't actually adding any heat. Yes the temperature rises along with the pressure but the boiling point of the steam also rises with the pressure. Also the gain in pressure and temp costs energy from the crank. So its hard to say if compressing the steam and exhaust has any advantages. It might just be a wasted stroke but I'm not exactly sure. If it is just a wasted stroke it will add a lot of heat and fricion loss.
A different configuration that you can think about is to have the steam expansion stroke during the the exhaust transfer. Say cylinder 2 & 3 are connected, while cyl 1 is pushing the exhaust into cyl 2 & 3 expansion occurs because of the diff in displacements. If there is any pressure in the exhaust than the force on cyl 2 & 3 will be double the force pushing on cyl 1 so there will be a net gain in torque. The water could be added in the transfer port as needed to maintain steady pressure. Then cyl 2 & 3 exhaust the steam and are ready for a steam stroke from cyl 4. If the expansion stroke of 2 & 3 is to large that you could bore and stroke or super charge cyl 1&4 to help get it balanced right.
|