Effect of Valve Opening Manner and Sealing Method on the Steady Injection Characteristic of Gas Fuel Injector

Abstract

The steady-state injection characteristic of gas fuel injector is one of the key factors that affects the performance of gas fuel engine. The influences of different injection strategies, such as different injection angles and different injection positions, on the mixing performance in gas-fueled engine have been emphasized in previous literatures. However, the research on the injection characteristics of the gas fuel injector itself are insufficient. The three-dimensional steady-state computational fluid dynamics (CFD) models of two kinds of injectors, in different opening manners, and the other two kinds of injectors, in different sealing methods, were established in this paper. The core region speed, stagnation pressure loss and mass flow rate were compared. Additionally, the effective injection pressure (EIP) concept was also used to evaluate the injection efficiency of gas fuel injector. The simulation results show that the jet speed of the pull-open injector is higher than the push-open injector under the same operating conditions. The injection efficiency of the pull-open valve is about 56.0%, while the push-open valve is 50.3%. In general, the steady-flow characteristic of the pull-open injector is better than that of the push-open one. The injection efficiency of the flat sealing injector is 55.2%, slightly lower than the conical sealing method.