Numerical Analysis on Mixture Formation in a Spray-Wall Complex Guided LPG DI Engine
A spray-wall complex guided combustion system was proposed by utilizing the fuel characteristics of liquefied petroleum gas (LPG).Simulation model was verified by the experiment using the Plane Laser-Induced Fluorescence (PLIF),and optimizations on injector position,injection angle,and piston cavity shape were made using a commercial CFD code,Fire V2011.Mixture formation for the new combustion system at typical part load (2 000 r/min) was numerically simulated.Simulation results show that at the injection timing of 40 ° CA BTDC,the LPG sprays injected from the upper two holes reach the spark plug at the ignition timing of about 20 ° CA BTDC,while the LPG spray injected from the lower hole is directed to the spark plug through the vertical vortexes at the same time.These two part of mixture form a stable richer stratified mixture around the spark plug,and the maximum global air-fuel ratio reaches 60.
direct injection engineliquefied petroleum gasspray-wall complex guidedstratified lean combustionnumerical analysis