不同辛烷值汽油对增压直喷汽油机影响的研究

通过台架试验，在涡轮增压缸内直喷（T—GDI）汽油机上研究辛烷值对车用汽油机动力性、经济性和排放的影响。试验结果表明：高辛烷值汽油能够提高汽油机的动力性，97号汽油在2000r／min时的外特性指示平均有效压力相对于95号汽油升幅达4．07％；在试验工况下，燃用高辛烷值汽油能够改善发动机的燃油经济性，中等负荷时油耗率降幅较大，而低负荷和高负荷时油耗率的降幅都较小，转速为2000r／min，制动平均有效压力为0．9MPa时油耗率最大降幅达2：8％；燃用高辛烷值汽油对降低THC、CO和NOx排放不利，97号汽油与95号汽油相比，大负荷时CO和THC的排放明显增加，NOx排放受转速和负荷共同影响，97号汽油与95号汽油相比，中高转速时随着负荷的增大，NOx的排放明显增加。

Study on the Effect of Different Octane Gasoline on Turbo-charged GDI Engine

The effect of octane number on engine power output, fuel consumption, and exhaust emissions were investigated for a turbo-charged gasoline direct injection（T-GDI） engine through bench test. The test results show that the power performance of the en- gine fueled with high octane gasoline could be improved, and the IMEP of the engine fuelled with 97# gasoline was up to 4.07% higher than that of 97# gasoline at the external characteristic of 2000r/min. The fuel consumption of the engine fuelled with 97# gasoline was lower than that of 95# under test conditions, and the decrease got bigger at the medium load, the maximum decrease was up to 2.8% when the speed reached 2000r/rain and the BMEP reached 0.9MPa. High octane number gasoline was adverse to reduce THC and CO and NOx emission. Compared with 95# gasoline, CO and THC emissions were increased significantly at high load under the test speed. NOx emissions were influenced by speed and load, it increased obviously at higher speed with load increased.