It is significant to study thermal balance of diesel engine under different variable geometry turbocharger(VGT)vane openings at variable altitudes,which is helpful to assess the heat distribution,control the heat load...It is significant to study thermal balance of diesel engine under different variable geometry turbocharger(VGT)vane openings at variable altitudes,which is helpful to assess the heat distribution,control the heat load and improve the heat efficiency of the diesel engine.A thermal balance test system was built to study the influence of the VGT vane opening angles on a regulated two-stage turbocharged(RTST)diesel engine’s thermal balance performance.The experiment was conducted under full load operating conditions at different altitudes(0 m,3500 m and 5500 m).Results indicated that the heat load of engine increased and the thermal efficiency decreased with the increase of altitudes under all operating conditions.As the VGT vane openings increased,the exhaust and maximum combustion temperature increased,while the maximum cylinder combustion pressure decreased.In particular,the maximum combustion temperature was more than 2000 K when the VGT vane openings were greater than 70%at the altitude of 5500 m,and the maximum combustion pressure exceeded 17 MPa when the opening of VGT vane was 70%at 0 m.The thermal efficiency of the engine decreased with the increase of VGT vane openings at the altitudes of 0 m and 5500 m,but the thermal efficiency increased and then decreased at the altitude of 3500 m.It was finally obtained that the best openings of VGT vane was 80%,60%and 50%under the engine speed of 2100 r/min at 0 m,3500 m and 5500 m,respectively.展开更多
Turbocharging and direct injection are main technologies used for energy-saving gasoline engines. But the biggest challenge is super-knock, whose mechanism is unclear and has no effective strategy to suppress this sup...Turbocharging and direct injection are main technologies used for energy-saving gasoline engines. But the biggest challenge is super-knock, whose mechanism is unclear and has no effective strategy to suppress this super-knock until now. The effects of injection strategies on super-knock were experimentally investigated in a turbocharged GDI engine. It was found that two-stage injections during intake stroke （TSII） can eliminate super-knock. Meanwhile, the fuel consumption, emissions and exhaust tem- perature can keep optimized level. By sweeping the start of the 1st injection （SOIl）, end of the 2nd injection （EOI2） and the split injection ratios （ROI2） using 5000 cycles evaluation test at low-speed high load operating point, the optimized injection strategy for the typical TC-GDI engine is TSII with SOIl at middle of intake stroke, EOI2 at end of intake stroke, and ROI2 of 0.3.展开更多
基金supported by Machinery Industry Key Laboratory of Engine Plateau Adaptation
文摘It is significant to study thermal balance of diesel engine under different variable geometry turbocharger(VGT)vane openings at variable altitudes,which is helpful to assess the heat distribution,control the heat load and improve the heat efficiency of the diesel engine.A thermal balance test system was built to study the influence of the VGT vane opening angles on a regulated two-stage turbocharged(RTST)diesel engine’s thermal balance performance.The experiment was conducted under full load operating conditions at different altitudes(0 m,3500 m and 5500 m).Results indicated that the heat load of engine increased and the thermal efficiency decreased with the increase of altitudes under all operating conditions.As the VGT vane openings increased,the exhaust and maximum combustion temperature increased,while the maximum cylinder combustion pressure decreased.In particular,the maximum combustion temperature was more than 2000 K when the VGT vane openings were greater than 70%at the altitude of 5500 m,and the maximum combustion pressure exceeded 17 MPa when the opening of VGT vane was 70%at 0 m.The thermal efficiency of the engine decreased with the increase of VGT vane openings at the altitudes of 0 m and 5500 m,but the thermal efficiency increased and then decreased at the altitude of 3500 m.It was finally obtained that the best openings of VGT vane was 80%,60%and 50%under the engine speed of 2100 r/min at 0 m,3500 m and 5500 m,respectively.
基金supported by the National Natural Science Foundation of China(Grant No.51036004)the Ministry of Science and Technology of China through the Project 2012AA111715
文摘Turbocharging and direct injection are main technologies used for energy-saving gasoline engines. But the biggest challenge is super-knock, whose mechanism is unclear and has no effective strategy to suppress this super-knock until now. The effects of injection strategies on super-knock were experimentally investigated in a turbocharged GDI engine. It was found that two-stage injections during intake stroke （TSII） can eliminate super-knock. Meanwhile, the fuel consumption, emissions and exhaust tem- perature can keep optimized level. By sweeping the start of the 1st injection （SOIl）, end of the 2nd injection （EOI2） and the split injection ratios （ROI2） using 5000 cycles evaluation test at low-speed high load operating point, the optimized injection strategy for the typical TC-GDI engine is TSII with SOIl at middle of intake stroke, EOI2 at end of intake stroke, and ROI2 of 0.3.
