高压共轨柴油机高海拔性能仿真研究

采用GT-Power软件建立了高压共轨柴油机工作过程模型,研究了等油量和等空燃比条件下柴油机性能随高原环境条件的变化规律。结果表明:等油量下,柴油机扭矩和燃油消耗率在海拔3 000 m以内中高转速范围基本保持不变;在海拔4 000 m以上标定转速下增压器超速,海拔5 000 m,900 r/min时发动机因空燃比过低而无法运行。等空燃比下,同0 m海拔相比,海拔5 000 m不同转速下发动机燃油消耗率平均增加7.2%,扭矩平均下降近40%,动力性下降严重。等油量或等空燃比方法不符合我国高原实际情况,需要建立新的柴油机性能高海拔修正或预测方法。

Simulation Study on Performance of High-pressure Common Rail Diesel Engine at High Altitude

The working process model of high-pressure common rail diesel engine was built with GT-Power software.Based on the same fuel supply and air-fuel ratio,the performance of diesel engine in plateau conditions was researched.The results show that,under the conditions of same fuel supply,the torque and specific fuel consumption of engine remain unchanged at medium and high speed within the range of 3 000 m above sea level,the speed of turbocharger exceeds the designed limit at engine rated speed beyond 4 000 m above sea level,and diesel engine cannot operate at the speed of 900 r/min because of the lower air-fuel ratio at 5 000 m above sea level.Under the conditions of same air-fuel ratio,the engine performance deteriorates more seriously.The specific fuel consumption increases by 7.2%averagely and the torque reduces by 40%averagely.Accordingly, the same fuel supply or same air-fuel ratio method cannot be appropriate for the domestic plateau condition.It is necessary to find the new high altitude performance correction or prediction method.