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
Waste heat recovery for internal combustion engine(ICE)has been considered as an important strategy to improve efficiency and promote fuel economy,thus alleviating the problems of energy shortage and environmental pol...Waste heat recovery for internal combustion engine(ICE)has been considered as an important strategy to improve efficiency and promote fuel economy,thus alleviating the problems of energy shortage and environmental pollution.This paper investigates the characteristics of various kinds of waste heat energy,namely,waste heat in exhaust,cooling water and charge air,over the engine’s whole operating region.Based on the energy balance experiments,the energy distribution of a conventional heavy-duty diesel engine is obtained under mapping characteristics.According to exergy analysis,the energy recovery potential for waste heat is studied as well.The experimental results indicate that exhaust energy increases with engine speed and load,while cooling water energy is more sensitive to load,especially at low and middle speed.Charge air energy,on the other hand,mainly counts on speed rather than load.Exhaust energy possesses the highest recovery potential in terms of both quantity and quality.Through waste heat recovery,a dramatic improvement in engine efficiency is achievable,actually,the maximum value can amount to 60%or even more.展开更多
The nitrogen oxide(NOx)release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification.In the present paper,different formulations of water in diesel emulsion fuels were pr...The nitrogen oxide(NOx)release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification.In the present paper,different formulations of water in diesel emulsion fuels were prepared by ultrasonic irradiation.The water droplet size in the emulsion,polydisperisty index,and the stability of prepared fuel was examined,experimentally.Afterwards,the performance characteristics and exhaust emission of a single cylinder air-cooled diesel engine were investigated using different water in diesel emulsion fuels.The effect of water content(in the range of 5%-10% by volume),surfactant content(in the range of 0.5%-2% by volume),and hydrophilic-lipophilic balance(HLB)(in the range of 5-8)was examined using Box-Behnken design(BBD)as a subset of response surface methodology(RSM).Considering multi-objective optimization,the best formulation for the emulsion fuel was found to be 5%water,2% surfactant,and HLB of 6.8.A comparison was made between the best emulsion fuel and the neat diesel fuel for engine performance and emission characteristics.A considerable decrease in the nitrogen oxide emission(-18.24%)was observed for the best emulsion fuel compared to neat diesel fuel.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.51206117)
文摘Waste heat recovery for internal combustion engine(ICE)has been considered as an important strategy to improve efficiency and promote fuel economy,thus alleviating the problems of energy shortage and environmental pollution.This paper investigates the characteristics of various kinds of waste heat energy,namely,waste heat in exhaust,cooling water and charge air,over the engine’s whole operating region.Based on the energy balance experiments,the energy distribution of a conventional heavy-duty diesel engine is obtained under mapping characteristics.According to exergy analysis,the energy recovery potential for waste heat is studied as well.The experimental results indicate that exhaust energy increases with engine speed and load,while cooling water energy is more sensitive to load,especially at low and middle speed.Charge air energy,on the other hand,mainly counts on speed rather than load.Exhaust energy possesses the highest recovery potential in terms of both quantity and quality.Through waste heat recovery,a dramatic improvement in engine efficiency is achievable,actually,the maximum value can amount to 60%or even more.
文摘The nitrogen oxide(NOx)release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification.In the present paper,different formulations of water in diesel emulsion fuels were prepared by ultrasonic irradiation.The water droplet size in the emulsion,polydisperisty index,and the stability of prepared fuel was examined,experimentally.Afterwards,the performance characteristics and exhaust emission of a single cylinder air-cooled diesel engine were investigated using different water in diesel emulsion fuels.The effect of water content(in the range of 5%-10% by volume),surfactant content(in the range of 0.5%-2% by volume),and hydrophilic-lipophilic balance(HLB)(in the range of 5-8)was examined using Box-Behnken design(BBD)as a subset of response surface methodology(RSM).Considering multi-objective optimization,the best formulation for the emulsion fuel was found to be 5%water,2% surfactant,and HLB of 6.8.A comparison was made between the best emulsion fuel and the neat diesel fuel for engine performance and emission characteristics.A considerable decrease in the nitrogen oxide emission(-18.24%)was observed for the best emulsion fuel compared to neat diesel fuel.
