Influence of fuel injection and intake port on combustion characteristics of controllable intake swirl diesel engine

In this study, the synergy effects of fuel injection system, intake system and combustion system on the combustion characteristics of the controllable intake swirl diesel engine were investigated. A research platform consisting of CFD numerical simulation and experiment was established in this study. In ways of combination of numerical simulation and experiment based on fuel injection test bed, intake steady flow test bed and single cylinder engine test, the prediction accuracy was improved. As such, the complex fuel spray and combustion phenomenon can be theoretically explained from the views of fluid dynamics and heat transfer, thus leading to further improvement of the engine combustion system. The optimal designs of fuel injectors were proposed and the corresponding fuel injection rate was derived which was used as initial input parameters for CFD numerical studies. Meanwhile by optimization of structure of intake port volute radius and the inlet and outlet section dimensions of spiral intake port, the swirl ratio is increased by 16.5% while the flow coefficient is increased by 4%. Finally, with the optimized fuel injection and air intake system, the effective power was found increased by 3.5% compared to the original diesel engine while the BSFC is reduced by 1.8 g/kW.h. NO emission is slightly increased while soot emission is reduced compared to original diesel engine combustion.