GEORG GEORGOVICH TER-MKRTICHIAN, ANDREY MIKHAILOVICH SAYKIN, KIRILLEVGENIEVICH KARPUKHIN, ALEXEY STANISLAVOVICH TERENCHENKO AND JULIA GEORGOVNA TER-MKRTICHIAN
Abstract
While converting diesel to gas engine the power decrease is compensated by forced induction. In order to prevent detonation geometric compression ratio is decreased, which results in decreased indicatedefficiency. The difference between geometrical and actual compression ratios is analyzed.Intake valve closing by the same value before or after bottom dead center causes similar decreasein actual compression ratio in comparison with geometrical compression ratio. Filling parametersare compared upon standard and reduced intake periods. It is demonstrated that early opening ofinput valve makes it possible to decrease actual compression ratio, decreasing detonation thresholdand preserving high geometrical compression ratio and high indicated efficiency. Short intakeprovides increase in mechanical efficiency due to decrease in pumping losses.