放气阀增压器在柴油机高原环境适应性改进中的应用研究

基于柴油机进排气高原环境模拟试验平台,针对所研制放气阀涡轮增压器,通过配机试验研究,获得结论如下:基于由冷态测量获得的放气阀开启特性,在考虑放气阀几何结构、排气脉冲压力波动等因素影响后得到预测特性,与高原模拟试验结果具有较好的一致性,偏差在7%以内;放气阀涡轮增压器具有较高的扭矩储备系数,可用于高原环境适应性动力改进,海拔4000 m工况可获得1.27扭矩储备系数,与常规增压器平原扭矩储备系数相当;在高原环境发动机进气量需要增加、压后压力需要提高的情况下,放气阀与平原工作状态近似,在最大扭矩点之后处于开启状态;与平原相比,高原4000 m工况压气机压后压力降低约60 kPa.通过更换高压比压气机放气阀涡轮增压器,在保持原有配机性能近似不变的情况下,可有效解决高原增压器超速问题,可使增压器转速在平原状态下降低10000 r/min左右,在高原4000 m工况,工作转速与更换前平原工作转速相当.

Application of Waste-gate Turbocharger in Plateau Environment Adaptability Improvement of Diesel Engine

In the plateau environment simulation test rig for intake and exhaust system of diesel engine ,the adaptability exper-imental investigation of newly developed waste-gate turbocharger was conducted .The results show that the predicted waste gate open characteristics based on measured data in standard state and considered factors including valve geometry and exhaust pressure wave have good consistency with the test results of engine plateau environment simulation with less than 7% devia-tion .Waste-gate turbocharger has a higher torque reserve coefficient and even in plateau environment .The coefficient is up to 1 .27 at an altitude of 4000 m and equivalent to that of general turbocharger at sea level ,which is helpful to improve the engine power at plateau .The waste gate at plateau has the similar work state with that of sea level to provide more intake air and high-er turbocharging pressure and remains open after the maximum torque points .The pressure at the exit of compressor decreases by 60 kPa at an altitude of 4000 m .Through replacing the waste-gate turbocharger with a high pressure ratio compressor ,tur-bocharger speed decreases by about 10000 r/min and the overspeed problem in high altitude environment is solved effectively . The turbocharger operation speed at 4000 m is the same as that at sea level before replacing .