Design of low temperature preheating system of hybrid electric tracked vehicle based on motor heating

For the tracked HEV, a new preheating system of powertrain is designed to solve the cold start problem in winter, in which the heat is generated by the drive motor running at very low speed. The new preheating system can meet the need of cold start. In order to get the heat from the power cabin to the outside environment, CFD numerical calculation is done for the heating process. The simulation results are verified through the relevant test. Based on the heat loss of power cabin and the parameters of engine cabin components, a heat transfer model of preheating system is established by using MATLAB. The total energy required for preheating at different ambient temperatures is calculated by this model. The energy losses and heating efficiency are obtained at different heating powers. The results show that the minimum heating power is 70 kW, and total energy is181 MJ. By considering the low temperature discharge rule of power battery, the heating power and battery capacity in the process of preheating are calculated for lithium iron phosphate batteries. The minimum battery capacity is 292 A·h.