Simulation Study Of Jet Controlled Compression Ignition On Premixed Combustion

Energy conservation and environmental protection are two urgent tasks facing society today. The traditional gasoline and diesel engines are difficult to simultaneously reduce emissions of NOx and soot. It is necessary to research and develop new low-emission combustion. Recently, numerous studies show that:homogeneous charge compression ignition (HCCI) engine can simultaneously reduce NOx and soot emissions, but there are many problems in commercial process. To solve the key problem of ignition phase which is difficult to control, this paper proposes a jet controlled ignition system (JCCI) to achieve high efficiency and low emissions, whose main principle is to add a secondary injector in the cylinder head, inject n-hexadecane fuel to ignite pre-mixed gas and control the ignition phase.Create CF186(A) three-dimensional model engine, simulation software AVL is used to study the process that a small amount of n-hexadecane ignites early diesel fuel spray mixture. The results show that:(1) JCCI is controlled low temperature premixed combustion. N-hexadecane injects into the cylinder and ignites fuel pre-mixture, and controls the ignition phase. N-hexadecane injection timing has a major impact on cylinder combustion. At15°CA BTDC the latest ignition phase injected into the n-hexadecane occurs. Advance or delay the injection, ignition phase will advance.(2) NOx and soot emissions can be reduced compared with the original diesel without after-treatment facilities. In the low load, NOx emissions canbe reduced by more than90%, the concentration of carbon emissions by more than6%; in At higher load, NOx emissions can be reduced by more than75%, the concentration of carbon smoke by more than45%. With the increase of EGR rate, the cylinder ignition phase delays, heat release rate and the peak of cylinder pressure decreases, cylinder temperature decreases, and the combustion duration extends.(3) Increasing the proportion of the n-hexadecane, ignition phase advances at first and then delays. The proportion of low calorific value of33.7%, the latest ignition phase occurs.