喷油正时对双燃料发动机低负荷性能影响的数值模拟

在基于过量空气系数控制的天然气-柴油双燃料发动机上,通过台架试验和计算流体动力学(CFD)数值模拟研究低负荷工况下喷油正时对双燃料发动机性能的影响规律.结果表明:发动机以中等转速、低负荷、 40%天然气替代率工作,适当喷油正时提前能够改善混合气质量与缸内燃烧情况.喷油正时为27°上止点前(BTDC)时,输出功率提升了18.44%,能量消耗率减少15.57%,同时一氧化碳(CO)和碳氢化合物(HC)的排放水平分别降低37.98%和39.51%.

Numerical simulation on the effects of injection timing on natural gas diesel dual-fuel engine at low load

On basis of the control strategy of excess air coefficient for a natural gas diesel dual-fuel engine , the influence of injection timing on combustion of the dual fuel engine under low load condition is investigated through bench test and CFD numerical simulation. The experimental results show that properly advancing injection timing enable to improve both mixture quality and in-cylinder combustion at medium speed, low load with 40% gas substitution rate. When the injection timing is advanced to 27°BTDC, power is increased by 18.44% and energy consumption is decreased by 15.57%. Meanwhile, CO and HC emissions are reduced by 37.98% and 39.51%, respectively.