[jeff88]

Originally Posted by wmjinman

I'm not sure if that's a steam engine or not, but it made me think of steam (I kinda have a "thing" for steam). But with pehaps not much more effort than your cylinder deactivation idea, a "steam-o-lene" design like Bruce Crower of Crower Cams came up with intrigues me.

What he does is has a special cam with additional lobes (convenient he's a cam manufacturer, huh?) that open the exhaust valves again, making it a 6-stroke engine instead of 4-stroke. Then there's an injector that squirts some water in at the start of the 5th stroke, which is the second power stroke - a STEAM power stroke.

So the engine goes like this:

> 1st stroke: Intake - intake valves open, piston moves down drawing in intake "charge"
> 2nd stroke: Compression - all valves closed piston moves up, compressing charge
> 3rd stroke: Power - all valves closed spark plug fires, fuel burn drives piston down
> 4th stroke: Exhaust - exhaust valves open, piston moves up, pumping exhaust out.

That's where a "regular" engine goes back to stroke 1, "intake". But in Crower's design, you get:

> 5th stroke: steam power - water is injected near TDC and heat causes steam, driving piston down again
> 6th stroke: steam exhaust - exhaust valve opens again due to 2nd cam lobe, piston moves up, pumping steam out.

And then you go back to stroke 1, Intake.

We always talk about all the waste heat in an internal combusion engine. This scheme uses the heat to make steam and more power. Cooling system could possibly be eliminated altogether. Imagine the "aero" possibilities if you didn't have a radiator you needed to get air to all the time!!!

Bruce calculated the potential efficiency improvement with his design, and it was substantial. Just going off my poor memory, it was something like 25% improvement in gas engines and even more - I wanna say 40% - in diesels!!! Patent pending, I believe...

That is an awesome idea! I was thinking about the theory of a 6 stroke engine like that last week, but I didn't think about steam! I wonder if there is a way to capture the steam, let it cool down to a liquid again (maybe at that point you would still need a radiator, or at least an intercooler) and then inject it again. You might have to put something like anti-freeze in for it to not rust anything and to keep the water from condensating out just like a 'normal' cooling system. Would the engine be hot enough to make the anti-freeze turn into steam with the water though? Also, I wonder if this would work with a turbo, where the steam would turn the turbo turbine rather than exhaust gases (or maybe both?).