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Old 01-27-2009, 08:48 PM   #29 (permalink)
wwest40
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Quote:
Originally Posted by Christ View Post
V engines are more likely to utilize the technology correctly than inline engines are. In a V engine, the air that gets pushed out can simply cross over the plenum to the next cylinder in the firing order, whereas in an inline engine, the airflow has to change directions 3 times.

Once in the reversion cycle that puts it out of the cylinder, then sideways in the plenum to the next cylinder's opening (which could be against airflow, going from 1-3 and 2-4, at least in Honda engines), then down the next cylinder's runner along with fresh air.
Look at it this way...

Using the current implementation of the Atkinson cycle, delayed intake valve closing and 13:1 "native" compression ratio, look at what would happen with just a single cyclinder engine. You would have reverse airflow OUT the intake path/duct for each compression stroke, not exactly viable for a MAF/IAT equipped engine.

It appears to me that you need to go to 4 cylinders, inline or whatever, before you arrive at a solution for the reverse flow problem. With 4 cylinders you have an "opposite" cylinder beginning an intake stroke at the same time you need a place to "put" the charge being "exhausted" due to the delayed intake valve closing of the cylinder just begining a compression stroke.

The only alternative to 4 cylinders that I can see is having a one way "reed" valve to block the reverse flow. Or, of course, the Miller cycle as chosen by Mazda in the Millenia S's V6.
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