Study On In-Cylinder Working Process Of Marine High-speed Gasoline Engine

A3D calculation model was built using AVL-fire software based on engine benchtest and its3D model. The model showed the intake-compression-combustion process of ahigh-speed port injection gasoline engine. To improve model accuracy, when calibrating thewhole model, we used repeated Grey Dynamic predicted theory and calibrated flame stretchfactor of the ECFM combustion module using experimental combustion heat release rate.The results showed a significant improve in model accuracy relative to recommended valueand cut-and-try method. Relationship between flame stretch factor and characteristicparameter calculated by the aforementioned calibrating method were also studied. Thecalibrating method used in this article showed the analysis and evaluation significance aboutinternal combustion process.The flow characteristics such as velocity field, pressure field and turbulence energydistribution of a five-valve port injection gasoline engine were analysed under fixedworking condition. The fluid variability under condition of middle valve non-synchronouswith two side valves and ignition moment were also discussed. Results indicatednon-synchronous valves lead to higher turbulence kinetic energy and flame spread speed inthe cylinder.At last, based on the calibrated3D calculation model, we studied variable of delayperiod, pressure rise rate, maximum outbreak of pressure, maximum release heat undervariable advance ignition angle and mixture concentration. The result indicated that variouscombustion performance indexes were optimized.