利用扫气抑制增压直喷汽油机爆震的试验研究

Experimental Study on Suppressing Knock of Turbocharged GDI Engine with Scavenging

通过台架试验研究了扫气对增压汽油机爆震的抑制效果。在转速为1 800 r/min,扭矩分别为150,200,250 N.m工况下,分析了扫气对点火提前角、进气流量和涡轮前端温度的影响。研究了相同节气门开度不同配气相位情况下,利用扫气改善大负荷下扭矩的潜力。结果表明:随着负荷的增加,扫气效果逐渐增强,发动机的点火提前角并不随着负荷的增加而推后,只是在一定区域内波动,进气流量增加,涡轮前端温度先降低后增加;大负荷下利用可变气门技术形成的扫气可以有效提高充气效率和动力性;在1 800 r/min下,发动机扭矩可以提高50 N.m。

The knock suppression of turbocharged GDI engine was researched on a test bench.Under the conditions of 150,200,250 N·m and 1 800 r/min,the influences of scavenging on ignition timing,intake air flow and temperature before turbine were researched.The ability of improving torque by scavenging was studied under the conditions of constant throttle opening but different valve timings.The results show that,with the increase of load,the scavenging strengthens,but the ignition timing does not retard.In a certain area,the temperature before turbine first decreases then increases with the increase of load.At high loads,the charge efficiency and power performance can be improved with the scavenging formed by using the variable valve timing technology.The torque can be increased by 50 N·m at the speed of 1 800 r/min.