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Old 07-11-2010, 09:10 PM   #149 (permalink)
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Quote:
Originally Posted by jdgFirefly View Post
I think this CO2 motor link was posted earlier in this thread. On a positive note it is simple and would be easy to make, but it wouldn't be vary eff. The steam isn't allowed to fully expand, and the remaining pressure is wasted. After the exhaust port is covered the piston wastes energy and a useless compression stroke.

I wouldn't say that a reciprocating motor has significant losses due to the laws of inertia. The energy of accelerating/decelerating the pistons isn't lost it is simply transferred to other cylinders and into the flywheel for example decelerating piston 1 helps accelerate piston 2. The energy is all transferred mechanical through solid parts so the losses are almost nothing. The only losses would be form increased friction on bearing surfaces due to the forces of acceleration (basically only the con rod bearing) and from the vary small amount of flex and dampening in the solid parts.
The se-saw logic of eliminating the cost of accelerating and decelerating reciprocating masses, is something I would tend to believe would make Newton laugh out loud.

I don't see a single cylinder engine as having your proposed energy transfer benefit that negates Newtons Law, and I find the logic behind such a rationale flawed. Are you saying that only a multi cylinder engine can benefit from the "energy transfer" you propose. I don't see that benefit present in any comparison of the efficiencies of engines based on their number of cylinders. Also consider 5 cylinder engines. One of the piston and rod assemblies has no second component to transfer it's energy to, which also supports my belief that such a phonemon does not exist.


A se-saw is a form of lever, not a rotating crankshaft with oscillating big rod ends converting the rotational energy of the crankshaft to the reciprocating piston.

Each piston accelerates from TDC to 90 degrees, then decelerates to 180 degrees. 4 strokes per combustion event. A mass forced to accelerate by combustion resists such acceleration becuse it contains mass. The fact that it has to rotate a crankshaft as well as other pistons, does not make it more efficient than it would be if there were no other pistons.

By that logic I must respectfully disagree with your post.

I do agree with you on the wasted compression on the CO2 motor, but I also think that the compression may not be as costly as you might believe, since it woul also combine with the pressure of the fluid entering the cylinder to create useful work.

A rotary valve could be utilized to eliminate the wasted compression with a timing that eliminated any pressurization on the up stroke of the piston.

regards
Mech
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