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Turbocharged 2-stroke with poppet valves and camshaft rotating same speed as crank?
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Posted by: Mechanicaldan ®

06/26/2005, 16:20:15

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Fist, start with a normal 4 stroke engine. Then, custom grind a cam so that the intake and exhaust both open and close in roughly 90 degrees. Spin the cam at the same speed as the crank. Now, turbo charge it so that the intake charge is forced in to the cylinder when the piston is at BDC. Basically it is now a turbocharged 2 stroke with poppet valves, but cleaner.

What are some potential problems with this design?

1. Would the cam profile be to extreme to open and close poppet valves in roughly 90 degrees? Wouldn't this just limit maximum RPM? What if pneumatic valves were used?

2. The exhaust gasses are not scavenged completely, but wouldn't it be benifical as a type of EGR?






Modified by Mechanicaldan at Sun, Jun 26, 2005, 16:21:33

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Re: Turbocharged 2-stroke with poppet valves and camshaft rotating same speed as crank?
Re: Turbocharged 2-stroke with poppet valves and camshaft rotating same speed as crank? -- Mechanicaldan Post Reply Top of thread Forum
Posted by: randykimball ®
Barney
06/26/2005, 22:11:54

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There are disels like that... some with only exhaust valves... often with four exhaust valves and scavenage ports..

some with cam operated intake and exhaust valves...

Some two stroke and some four stroke... the thing is when you put four cycles in one revolution you have a hard time not getting some fuel mixture pushed out the exhaust, because you must exhaust and intake during the down cycle. It takes a long stroke so there is time for both to happen... unless you burn methanes RPM's suffer so you have time.... It is a parodox, waste a rotation or waste fuel into the enviornment. ...The enviornment needs to win... thus the two full revolution four stroke is king... again...
a full stroke of power, a full stroke of exhaust, a full stroke of intake, and a full stroke of combustion. .. easy to control what mixture goes where.... Fluid flow, getting as much OX as possible into the chamber with the correct mix of fuel and moisture, getting as much compression as you need without pre-det, and getting the max from the power stroke, then getting rid of ALL that burned mixture with a complete burn is vital for getting a clean engine.... atleast that is what I got from schooling.....back when.
-randy-




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