A Study on Surging Phenomena in Diesel Engine Air-Charging System

Abstract

Pulsating air flow in a diesel engine air-charging system caused by the opening and closing of the scavenging ports produces surging phenomena which are considerably different in their characteristics from those observed in the ordinary, steady flow blower system. By substituting a simple model for the engine air-charging system, the authors analyzed the surging phenomena through theoretical calculations and determined the effects of each model element on the surging. A series of experiments were then made to verify the validity of the analytical calculation method adopted. A good agreement was observed between the results of calculations and experiments, and it was found that a simplified theoretical calculation neglecting the influence of the pressure waves in the air duct of the air-charging system could serve as an effective means to deal with the surging phenomena where the air duct was comparatively short in length as that of the diesel engine.