Research On Control Strategy Of Intelligent Cooling System For Hybrid Diesel Engine

The modern engine adopts more compact and higher power density design,and the heat load of the engine is increasing.At the same time,the market demands more and more strict for the economy and emission of the engine,so there are higher requirements for the temperature control and power consumption optimization of the cooling system.But the traditional cooling system has many limitations.The application of electronic control components and technology in the field of automobile provides a direction for the further development of cooling system,which changes the cooling system from passively controlling temperature to actively managing energy to achieve high efficiency of engine.It provides a potential better solution for improving cooling effect and overall efficiency.The advanced intelligent cooling system can not only ensure the accurate control of engine coolant temperature,but also reduce the power consumption of cooling system components.Therefore,it is of great engineering significance to study the control strategy of engine intelligent cooling system.In this paper,YCK08 engine is taken as the research object,and the control strategy of engine cooling system is studied.Firstly,the influence of coolant temperature on engine economy is explored through engine bench test,so as to determine the control basis of cooling system.Then,GT-SUITE is used to build the one-dimensional simulation model of engine cooling system,and the calibration of flow characteristics and heat transfer characteristics is completed to provide a correct model for the development of control strategy.Then,the extended working conditions of cooling system water pump and fan are calculated by using the DOE function of the model.Afterwards,the DOE function of GT-SUITE is used to calculate the extended working conditions of coolant pump and fan.Taking the minimum power consumption of accessories and accuracy of coolant temperature control as objective,three control strategies,namely,FC,VUFZ and VUFZ with pump PID control,are designed respectively.The results of simulation calculation and comparison under WHTC condition in bench and real road show that,VUFZ can reduce the coolant temperature amplitude by 37.6%,increase the time when temperature error within ±0.5 ℃ by39.98%,and reduce the accessories power consumption by 8.58%,which improve the cooling system performance significantly.VUFZ with pump PID control can further reduce temperature amplitude by 16.1%,increase the above time by 15.26%,but increase accessories power consumption by 10.3%,which improves the accuracy of temperature control by sacrifices power consumption.Based on the above research,the map feedforward and VUFC strategy is proposed to achieve the overall optimization of temperature control accuracy and power consumption.Compared with the FC,the temperature control accuracy in the vehicle operation environment is improved by 49.28% and the power consumption is reduced by 8.68%.