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Old 10-18-2013, 12:57 PM   #29 (permalink)
Sean.Heihn
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Join Date: Apr 2013
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Land Shark - '11 Toyota Yaris 3dr Hatchback
Team Toyota
90 day: 36.68 mpg (US)
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So does the FXE always run in Atkinson? I think it does, according to the valve timing, it just varies from mild to heavy Atkinson 'effect'. Actually, it really isn't Atkinson cycle, since that requires a engine with a special crank that varies piston stroke length. It's more like a superchargerless Miller cycle, to create an Atkinson-like effect. Toyota actually calls it simulated Atkinson. About the FE and Atkinson, why would the intake stay open that long at low RPM? I could see at high RPM to insure a more complete intake draw, but at low speed I don't see how it couldn't intake enough charge to fill the cylinder. FYI, at high speed, the intake closes at 12* ABDC, low speed, 52* ABDC, that doesn't make sense to close the intake sooner at high RPM, unless you want a mild Atkinson effect. That would give you the results of lean burn at idle/low load, decreased fuel consumption, without the increased NOX emissions.
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