Effect of annular injector geometry and different injection functions on diesel engine performance: A numerical study

Changing the injector orifice geometry has major impact on diesel engine performance. In this study, the geometry of the injector outlet is changed from circular to annular, and the effect of different injection functions on the performance of the diesel engine is investigated. The results are compared with the results of the Kubota ۳۳۰۰ engine. Numerical simulations are conducted by using AVL Fire commercial code. The results show that the annular injector provides the better fuel distribution inside the combustion chamber of the engine by increasing the fuel angle. The use of changing fuel injection rates in the annular injector also improves engine performance. The best performance is observed for the constant-increasing function, and the specific fuel consumption value reached ۰.۱۸۶۵. By applying new injection functions, as well as using the new presented annular injector, power also increases. As an instance, for the constant-increasing function (fourth function), although the amount of fuel injection per engine cycle is decreased by ۸.۸%, power increases by ۱۳.۶% and ۱۳.۵%, respectively. While NO pollutant increases slightly by changing the type of injector and using spray functions, the soot produced at the beginning of the combustion process is well oxidized before the end of the power stroke, and its amount reaches less than ۲e-۶.

Keywords:

Annular injector , injection function , numerical method , SFC , diesel engine performance