Evaluation and Simulation Analysis of Mixing Performance for Gas Fuel Direct Injection Engine under Multiple Working Conditions

Gas fuel direct injection (DI) technology can improve the control precision of in-cylinder mixing and combustion process effectively avoid volumetric efficiency reduction in a compressed natural gas (CNG) engine, which has been tendency. However, compared with port (PFI) method, former’s path duration are shortened greatly, often leads to poor uniformity. What is worse, performance would be seriously affected by engine working conditions, such as speed load. Based on this situation, fluid mechanics software FLUENT used article, computational dynamics (CFD) model gas-fueled established. A quantitative evaluation mechanism CNG proposed explore influencing rule different speeds loads performance. The results indicate that phase space analysis accurately reflect characteristics mixture process. rapidly occupies cylinder volume stage. During transition stage, highly transient state. diffusion stage characterized continuous homogenization mixture. linearly dependent engine’s condition space.