Quote:
Originally Posted by Kzelisko
The only way to disable a cylinder that will actually reduce fuel usage, would be to stop the valves from opening on that cylinder, either by removing rockers or grinding the lobe down or what not.
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I seem to remember Cadillac selling a variable cylinder engine (the 4-6-8) that rotated the "off" cylinders so that they didn't end up with a single dead cylinder that filled with unburned oil. If one could program the Prius engine to four firings and one skip, (1,3,4,2,X,3,4,2,1,X,4,2,1,3,X,2,1,3,4,X,....), giving sixteen firings per ten revolutions, (or 80% the firings of a non-modified four cylinder) one might attain a 20% improvement in cruising mileage while not damaging the one cylinder.
Another rotating pattern might be to skip every third firing (1,3,X,2,1,X,4,2,X,3,4,X,....), giving eight firings per six revolutions. (66.666...% the firings of a non-modified four cylinder)
Taken to absurdity, firing one, and skipping the next two (1,X,X,2,X,X,4,X,X,3,X,X,....) would yield four firings per six revolutions,(33.333...%) rather than the normal twelve.
Might make sense on an older non-hybrid four, but it doesn't really make sense on a Prius.