Integrated vehicle thermal systems simulation-based approach for sizing of eTruck Radiator and fan

Properly sized under hood components in an electric vehicle is important for effective thermal cooling at different load conditions. Powertrain (PT) aggregate loop plays significant role in generating heat with heat sources like eMotor, inverter, VFD, OBC etc. Radiator being the most critical part in electric vehicle (EV) which acts as a heat sink for these powertrain components. Radiator with the help of coolant cools heat generated by different components in powertrain loop. It becomes important to understand the heat generated by the PT components at different drive/load scenarios and decide on the correct sized radiator and fan. Rightly sized radiator and fan combination helps to balance the trade off of precise thermal needs in eTruck to an oversized/undersized components. Main objective of this study is to estimate heat loads from system model representing powertrain aggregate components in later to study the existing radiator capacity and propose the proper sized radiator and fan. Present work is carried out using both three and one dimensional commercial CFD softwares StarCCM+ and GT-suite. Air mass flow rates on the condenser and radiator for different vehicle and fan speed is calculated using StarCCM+ with the complete vehicle model. Vehicle underhood parts is then represented in Cool-3D software with given radiator, condenser and fan specifications by supplier. PT loop with all the plumbing and components are modelled in GT-Suite. All these models are integrated in GT-Suite and calibrated with test data on flow and thermal. Integrated model is first validated for eMotor startability and gradeability results for different load cases. DOE studies have been carried out to understand existing radiator capacity for realistic scenario cases of different ambient conditions and vehicle speeds. The heat load data is analyzed to arrive at sufficiency and efficiency of existing radiator & fan configuration and later derived to understand derate quantification. Iterative studies are carried out using GT-Suite to achieve suitable combination of radiator and fan, which will take care of the eDrive load generated even for worst-case scenarios