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GTR wrote:Video: The Real Atkinson Cycle
Watch the video > click >> The Real Atkinson cycle
You might have heard the term "Atkinson cycle" associated with hybrids. There, unorthodox valve timing of the gasoline engine trades away a little power for enhanced efficiency. It's just the thing for optimal interaction of a hybrid's gasoline engine and electric motor. In fact, the Toyota Prius, Ford Fusion, Chevrolet Tahoe and other hybrids claim Atkinson operation.
In fact, these are only simulated Atkinsons. The real Atkinson cycle displays differences in piston travel, the intake and compression strokes are actually shorter than the subsequent expansion and exhaust strokes.
This video displays a neat cutaway of Honda's experimental Extended-Expansion General Purpose Engine, a single-cylinder powerplant intended for portable generators, lawn mowers and the like. Key to its operation is a multiple linkage of the engine's connecting rod and crankshaft. Like the original Atkinson "Cycle," circa 1886, its intake and compression strokes are shorter than those of expansion and exhaust. Thus, as well, there's a difference in displacement: 135.2 cc for intake/compression; 203.6 cc for expansion/exhaust. Compression ratio is 8.5:1; expansion ratio, 12.3:1, and one result of this is a 20-percent improvement in fuel efficiency.