Power deterioration is a major problem for diesel engines operating at high altitudes.This problem stems from the limited availability of turbocharger energy,which is not enough to increase the boost pressure to the r...Power deterioration is a major problem for diesel engines operating at high altitudes.This problem stems from the limited availability of turbocharger energy,which is not enough to increase the boost pressure to the required level.In this study,a control strategy is introduced in order to achieve engine power recovery at different altitudes.It is shown that as the altitude increases from 0 to 4500 m,the required boost pressure ratio increases from 2.4 to 4.3.The needed turbocharger energy should be increased accordingly by 240%,and the TCC(turbine characterization coefficient)should be adjusted within wide ranges.A 12%decrease in the TCC can lead to a rise of the intake air pressure,which can compensate the pressure decrease due to a 1000 m altitude increase.The fluctuation range of boost pressure was within 14.5 kPa for variations in altitude from 0 to 4500 m.展开更多
Turbocharging with the addition of Exhaust Gas Recirculation (EGR) is considered as an effective measure to meet strict regulations in near future, but there are problems in obtaining the required EGR ratios at higher...Turbocharging with the addition of Exhaust Gas Recirculation (EGR) is considered as an effective measure to meet strict regulations in near future, but there are problems in obtaining the required EGR ratios at higher loads for turbocharged diesel engines. In this paper, three new EGR systems are introduced that will make effective use of pressure waves in intake and exhaust manifolds. The simulations of the EGR systems and some experiments for validating the simulation model have been made. The simulation results show that a large amout of EGR can be achieved at higher engine loads and even at full engine loads by using these EGR systems.展开更多
To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The c...To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.展开更多
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
基金funded by the National Natural Science Foundation of China[Grant Nos.51576129 and 12102298]the China Postdoctoral Science Foundation[Grant No.2021M702443]the State Key Laboratory of Engines(Tianjin University)[Grant No.K2022-09].
文摘Power deterioration is a major problem for diesel engines operating at high altitudes.This problem stems from the limited availability of turbocharger energy,which is not enough to increase the boost pressure to the required level.In this study,a control strategy is introduced in order to achieve engine power recovery at different altitudes.It is shown that as the altitude increases from 0 to 4500 m,the required boost pressure ratio increases from 2.4 to 4.3.The needed turbocharger energy should be increased accordingly by 240%,and the TCC(turbine characterization coefficient)should be adjusted within wide ranges.A 12%decrease in the TCC can lead to a rise of the intake air pressure,which can compensate the pressure decrease due to a 1000 m altitude increase.The fluctuation range of boost pressure was within 14.5 kPa for variations in altitude from 0 to 4500 m.
文摘Turbocharging with the addition of Exhaust Gas Recirculation (EGR) is considered as an effective measure to meet strict regulations in near future, but there are problems in obtaining the required EGR ratios at higher loads for turbocharged diesel engines. In this paper, three new EGR systems are introduced that will make effective use of pressure waves in intake and exhaust manifolds. The simulations of the EGR systems and some experiments for validating the simulation model have been made. The simulation results show that a large amout of EGR can be achieved at higher engine loads and even at full engine loads by using these EGR systems.
基金the Ministerial Level Advanced Research Foundation (37256)
文摘To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.
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.
