Half a croissant, on a plate, with a sign in front of it saying '50c'
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4 stroke hybrid

2 stroke gas + 2 stroke steam
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Use the following 4 stroke sequence to acchieve the best of a two stroke gas engine and six stroke cowler steam hybrid engine.

1) start the cycle at bottom dead center; perform scavenging, close the ports, inject fuel, compress, and fire the spark plug.

2) expand the burnt gasses.

3) open the exhaust port and expell the gasses out the exhaust.

4) close the exhaust port, inject water onto the engine piston, expand the steam generated, and open the exhaust port.

Note that the scavenging done in step 1 replaces expanded steam in the cylinder with fresh air.

We get a power stroke on every rotation of the shaft, just like a regular two stroke, but use fuel only every other rotation.

And, unlike a 6 stroke engine, we don't *need* to have two "idle" strokes when the engine is cold; we could just use an alternate camshaft, and peform a normal two stroke cycle when the engine's cold and a four stroke steam hybrid cycle once the engine's heated up.

goldbb, Jan 04 2009

Crower 6-stroke http://en.wikipedia...i/Crower_six_stroke
prior art [afinehowdoyoudo, Jan 04 2009]

Air Scavenging http://en.wikipedia...enging_(automotive)
how the steam would be replaced with fresh air [goldbb, Jan 06 2009]


       Iron_horse: I *did* mention (both in the first and last paragraphs) the Crower six stroke engine; however, it is not precisely "prior art."   

       Crower's engine uses 6 strokes, mine uses 4.   

       Crower's engine gets power on 1/3 of the strokes, mine gets power on 1/2.   

       Crower's engine uses an exhaust stroke to get the steam out of the piston, mine uses scavenging.   

       Crower's engine uses an intake stroke to get fresh air into the piston, mine uses scavenging.   

       When a Crower six stroke engine is cold (during engine startup) the last two strokes out of 6 are idle (the piston goes down and up with the valves closed and no work being done). In my design, if the engine is cold, the 3rd and 4th strokes change from "exhaust" and "steam inject, expand" to "scavenge, compress, combust" and "combust, expand."   

       Thus, when a Crower six stroke engine is cold, it gets power on only 1/6 of the strokes. In my design, when the engine is cold, power is provided on 1/2 of the strokes.   

       This change can be accomplished by having a seperate camshaft, or perhaps different cam profile, for hot engine functioning and cold engine functioning... or even without any mechanical change at all, if the engine is camless.
goldbb, Jan 05 2009

       'Prior art' was meant as.. 'your point of departure'.. linked because sp. cowler in idea. (+)
afinehowdoyoudo, Jan 07 2009

       Oh, ok. Thanks, then.
goldbb, Jan 08 2009


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