点火方式对汽油机燃烧过程的影响

Influence of Ignition Mode on Combustion Process of a Gasoline Engine

通过基本结构的微小变动,将单火花塞点火(single spark ignition,SSI)改造成双火花塞点火(dual spark ignition,DSI),运用三维仿真软件AVL FIRE模拟仿真,并通过试验验证。再对单火花塞点火、双火花塞同步点火(dual synchronous spark ignition,DSSI)、异步点火(dual asynchronous spark ignition,DASI)3种不同的点火方式进行对比。结果表明:在6500 r/min转速全负荷状态下,空气过量系数为1.00而其他参数调整为最佳时,单火花塞的最佳点火提前角为29°,在空气过量系数为1.15的最佳参数下,双火花塞同步点火的最佳点火提前角为22°,双火花塞异步点火的最佳点火提前角为22°和24°。其中,发动机综合性能在双火花塞异步点火条件下表现最好:相对于单火花塞点火指示功提升8.49%;相对于同步点火,可将最高燃烧压力和压缩负功减小,指示功提升3.60%;同时改善了排放性。上述研究中发动机均控制在未发生爆震情况下。

On the basis of only minor modification to the basic structure of a gasoline engine,the original single spark plug ignition was transformed into a double spark plug ignition.And three-dimensional simulation and experimental verification were carried out.Then,a comparative analysis of three different modes of using spark ignition,double spark synchronous and asynchronous ignitions was made.The results of the tests show that at the speed of 6500 r/min and under full load conditions,the best ignition advance angle for the single spark ignition is 29°in crank angle with an excess air ratio of 1.00,and for the double spark synchronous and asynchronous ignitions,the corresponding advance angles are 22°and 22°/24°,respectively,with an excess air ratio of 1.15.As observed,use of double spark asynchronous ignition allows the engine to have the best overall performance.Compared with the single spark ignition,it can increase the available work by 8.49%,and compared with the double spark synchronous ignition,it can improve available work by 3.60%with the reduction of burst pressure and compression work,and hence exhaust emissions.In the above tests,the engine is always controlled to operate in the non-detonation zone.