> But the difference is that the heating block/head would not > require cooling - it would remain substantially at the same > temperature and just be used to flash the water spray to > steam. The hot steam would then be ejsvted in the exhust > cycle ready for the next injection. I like the idea but think > that the running speed would be limited. I'm glad someone gets it. I'm amazed at the number of replies that show a complete misunderstanding of the idea. No, it doesn't require cooling. No, it doesn't require high pressure injection: No compression and the injected water is NOT boiling. Yes, you probably have to increase the surface area inside the cylinder head to ensure a rapid transfer of heat. Yes, it will turn over slowly, who cares? No, preheating the injected water isn't a big deal, just bodge up a heat exchanger from copper tubing with the exhaust steam and the intake water. No, it isn't supposed to be efficient, the sun is free: trash 99% of it but get that 1% at very low cost without high pressure danger. Sure, a sterling engine would be better, but that isn't the point... ...this is cheap, simple, safe, and accessible to the little guy. Where can I buy a sterling engine right now? How much does it cost? Starlings are pipe dreams. http://techref.massmind.org/techref/idea/mc-heat-inject.htm > I've actually been thinking of a similar effect by injecting > water into a petrol engine. Similar effect except that the > burning petrol is used to vaporize the water. It is a > recognized technique for efficiency improvement. > The benefits are quoted as reducing engine operating > temperature while increasing mpgs. Most benefit is obtained > if the timing is advanced somewhat. Apparently the optimum > mix is about 1/20 to 1/10 of the fuel so the effect is not > massive. (maybe 5% improvement) I just have to be able to > measure the fuel usage on the fly and meter the water > appropriately. And not care too much if I damage the engine, > which is a sticking point at the moment. That is about what my dad found. He ran water injection on his 1968 E-type Jag for many years. It gave him 2 mpg more for a total of 26, allowed more advanced timing without pinging and kept the engine exhaust system quite a bit cooler which is what he was worried about. He used it as a sort of variable compression system. More water was injected when the engine was not under load. The timing was advanced a tad. When he floored it, the water cut out and the timing was retarded. Water injection into a petrol engine is limited by the amount of heat produced by the explosion which really isn't that much. The sun can provide much more heat at little or no cost. Just the cost of a batch of old 1' decorator mirrors and something to mount them on. Another thing my dad made was a solar powered boiler for energy generation. The mirrors were each held by a scrap of sheet metal with the ends bent up at the tip and then bent at the center into a V. The mirror was held at the top of the V by the bent tips and the bottom was welded to a bit of narrow rebar which was then welded to a frame and bent to align the mirror. The frame was 12'x12' made from electrical conduit and strengthened by guy wires to posts along the central axis. This entire frame was suspended in the air in a cradle that allowed it to track the sun. It flexed like all heck, was very heavy and we never did put all the mirrors on it. Here is another idea: Put the mirrors on the ground. You can prop them up with rocks if you want. Align them at night with a laser pointer and a target in the center. Hang the pointer on a string from a tripod which is placed over each mirror like a plumb bob then move the mirror until the beam hits the target. Next day, you have a small copy of the sun tracking through the air over the mirror field. Then, put the engine and generator in the air on a post and move them to match the focal point of the mirrors. Since there is no high pressure feed to run to the motor and no hot exhaust to run out, the only thing that needs to follow them is a water hose going in, and an electrical cable going out. I would probably use two arms and a pole between them with the motor / generator mounted in the middle. For safety and to help concentrate the heat on the head of the engine, a second "collar" mirror of metal could be made and placed around the head facing down. And yes, I did see the episode of Myth busters where they tried to light up the boat. But that rig was so floppy that they had no focus at all. It was probably multiplying the sun by a factor of 5, if that, on any given point. And the heat had a nice shiny coated surface to bounce off of. Try this: Take a stack of razor blades about an inch thick and hold them together pointed edge on at the sun. See how long you can hold on. The radiation goes down in-between the blades and bounces around in the cracks about a million times until all the heat is absorbed. It's been a lot of years since my dad showed me that, but I seem to remember I couldn't hold it more than a few seconds. What if you made a head for an engine like that? Blades sticking up on top and down inside as well. Hit that with some sunlight on the outside and spray water onto it from the inside. --- James Newton, massmind.org Knowledge Archiver james@massmind.org 1-619-652-0593 fax:1-208-279-8767 All the engineering secrets worth knowing: http://techref.massmind.org What do YOU know? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist