Based on the principles of heat transfer,an oil film model in the engine cylinder was established.Under the condition of cold state,the influence of factors such as engine fuel injection,fuel drop point,cylinder inne...Based on the principles of heat transfer,an oil film model in the engine cylinder was established.Under the condition of cold state,the influence of factors such as engine fuel injection,fuel drop point,cylinder inner wall temperature,and inlet fluid on the oil film is comprehensively considered to establish an oil film quality prediction model.Based on the measurement of the compensation oil quantity in the transition conditions,the variation of the oil film during the transition is analyzed.The experimental results show that the velocity of the air-flow in the intake port and the temperature and pressure on the wall of the intake port are the main factors affecting the oil film in the cylinder.Based on the abovementioned experimental and theoretical studies,an oil film distribution model for each cycle of the transition condition was established based on the engine inlet oil film model.The experimental measurement curve and model prediction curve for the fuel compensation per cycle in the transition condition from 10%load to 30%load.The model established can be in good agreement with the experimental results and meet the fuel compensation trend in the transition condition.While realizing the fuel compensation for the transient conditions,this work is definitely helpful to achieve accurate control of the air-fuel ratio.展开更多
48 V lithium battery micro hybrid system is the most fuel economy vehicle which can be mass produced at present.However,with the irreversible internal resistance increase of the key component 48 V lithium battery,and ...48 V lithium battery micro hybrid system is the most fuel economy vehicle which can be mass produced at present.However,with the irreversible internal resistance increase of the key component 48 V lithium battery,and the capacity continues to decline,the system performance deteriorate.Worst case could be the system not functional in the middle and later age of vehicle life cycle.This paper studies the feasibility of using 48 V super capacitor as the replacement to 48 V lithium battery,and uses a 12 V module of 48 V super capacitor as the traditional 12 V power supply,further reducing the number of components or reducing the demand for parts of 48 V micro hybrid system.This paper analyses the 48 V super capacitor micro hybrid system scheme,based on which a prototype is built,and carries out the vehicle comparative test.The results show that:(1)The performance of 48 V super capacitor micro hybrid system perform comparably with 48 V lithium battery micro hybrid system,and 12 V multiplexing function does not cause power loss of super capacitor;(2)The SOC fluctuation of super capacitor is larger than that of lithium battery,but it can satisfy all test conditions through the strategy;(3)The voltage mutation of super capacitor is smaller than that of lithium battery.It can greatly reduce the impact of voltage on vehicle electrical appliances.The 48 V super capacitor micro hybrid system with 12 V multiplexing function is of great significance.展开更多
文摘Based on the principles of heat transfer,an oil film model in the engine cylinder was established.Under the condition of cold state,the influence of factors such as engine fuel injection,fuel drop point,cylinder inner wall temperature,and inlet fluid on the oil film is comprehensively considered to establish an oil film quality prediction model.Based on the measurement of the compensation oil quantity in the transition conditions,the variation of the oil film during the transition is analyzed.The experimental results show that the velocity of the air-flow in the intake port and the temperature and pressure on the wall of the intake port are the main factors affecting the oil film in the cylinder.Based on the abovementioned experimental and theoretical studies,an oil film distribution model for each cycle of the transition condition was established based on the engine inlet oil film model.The experimental measurement curve and model prediction curve for the fuel compensation per cycle in the transition condition from 10%load to 30%load.The model established can be in good agreement with the experimental results and meet the fuel compensation trend in the transition condition.While realizing the fuel compensation for the transient conditions,this work is definitely helpful to achieve accurate control of the air-fuel ratio.
基金The National Key Research and Development Program for New Energy Vehicles in 2018“Power System Platform and Vehicle Integration Technology for Extended-Range Fuel Cell Cars”(2018YFB0105400)。
文摘48 V lithium battery micro hybrid system is the most fuel economy vehicle which can be mass produced at present.However,with the irreversible internal resistance increase of the key component 48 V lithium battery,and the capacity continues to decline,the system performance deteriorate.Worst case could be the system not functional in the middle and later age of vehicle life cycle.This paper studies the feasibility of using 48 V super capacitor as the replacement to 48 V lithium battery,and uses a 12 V module of 48 V super capacitor as the traditional 12 V power supply,further reducing the number of components or reducing the demand for parts of 48 V micro hybrid system.This paper analyses the 48 V super capacitor micro hybrid system scheme,based on which a prototype is built,and carries out the vehicle comparative test.The results show that:(1)The performance of 48 V super capacitor micro hybrid system perform comparably with 48 V lithium battery micro hybrid system,and 12 V multiplexing function does not cause power loss of super capacitor;(2)The SOC fluctuation of super capacitor is larger than that of lithium battery,but it can satisfy all test conditions through the strategy;(3)The voltage mutation of super capacitor is smaller than that of lithium battery.It can greatly reduce the impact of voltage on vehicle electrical appliances.The 48 V super capacitor micro hybrid system with 12 V multiplexing function is of great significance.
