Abstract
Effective compression ratio was reduced by limiting the intake duration. This paper investigates the effect on thermal efficiency with discrepancy of compression ratio and expansion ratio for a compression ignition engine.
A simple thermodynamics model analysis shows that a small thermal efficiency improvement is predicted by consideration of the influence of pressure ratio. Experimental results show certain improvements, more than thermodynamics analysis prediction, for BSFC at partial load. In a study of the result, it is found that a principal cause of the improvement is reduction of total friction loss in the engine with reduction of the maximum cylinder pressure.
