Simulation of the fuel stream injection in wall guided in spark ignition engine

Wall guided direct injection system is one of the most frequently met in modern car gasoline direct injection engines. In technical solutions where gravitational fuel charge movement occurs, concave piston head needs to be extended with specially shaped ascent. This additional surface guide's injected fuel stream in area of spark plug and forms centrally stratified fuel charge. Injector to cylinder axis inclination angle in wall guided direct injection engines is one of critical parameters which decide of combustion process flow. It determines density of injected fuel stream and air-fuel ratio which has to be less than l in spark plug area. 3D Studio MAX offers advanced module - Particle System - Super Spray which enables to simulate behaviour of injectedfuel spray. These simulation runs resulted in fmding optimal range of injector to cylinder axis inclination angle for the modelled direct injection engine. Results obtained from the simulation confirmed importance of injector to cylinder axis inclination angle as a construction parameter. However injection pressure doesn 't impact fuel stream movement direction, it impacts time after which injected fuel stream reaches spark plug's electrodes. Undesired effect of increasing pressure value is higher fuel stream dissipation what dominates advantageous effect of shortening the time. This can be achieved by decreasing distance between injector and spark plug like in spray guided direct injection engines.