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Unformatted text preview: 2.6. RECIPROCATING ENGINE POWER CYCLES 55 B 2R crank S Figure 2.15: Piston-cylinder configurations illustrating geometric definitions. For these engines the volumes are closed in expansion and compression, so the net work is w net = contintegraldisplay P dv = P meff ( v max − v min ) . (2.344) Here one has defined a mean effective pressure : P meff . The net work per cylinder per cycle is W net = mw net = P meff m ( v max − v min ) = P meff ( V max − V min ) . (2.345) Now consider the total power developed for all the cylinders. Assume the piston operates at a frequency of ν cycles/s : ˙ W net = N cyl P meff ( V max − V min ) ν. (2.346) It is more common to express ν in revolutions per minute: RPM = ν (60 s min ), so ˙ W net = P meff N cyl ( V max − V min ) bracehtipupleft bracehtipdownrightbracehtipdownleft bracehtipupright = V displ RPM 60 s min , (2.347) = P meff V displ RPM 60 s min . (2.348) This applies for a two-stroke engine. If the engine is a four stroke engine, the net power isThis applies for a two-stroke engine....
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- Fall '11
- Dynamics, Two-stroke engine, compression ratio, Otto cycle, Four-stroke engine, Internal combustion piston engines