Thermal Modeling of Electronics Inside a Truck Cabin

Sammanfattning

Electronic Control Units(ECUs) are critical components in trucks, which are required to be operated within specific temperature ranges to minimize its failurerates. Some of the ECUs have integrated safety functions, and failure of these couldresult in the breakdown of the vehicle. These are often mounted underneath theInstrumentation Panel(IP), a confined space that also houses other heat sources,complicating their thermal management. Therefore, to understand the thermal behavior of ECUs under various conditions, Computational Fluid Dynamics(CFD) wasused.The CFD model was used to study the effects of factors such as ambient temperature, recirculation, and vehicle velocity on the ECU’s thermal performance. AProportional-Integral(PI) controller was modeled to regulate the air temperaturethrough the HVAC(Heating, Ventilation, and Air Conditioning) ducts to maintainthe cabin temperature at 22◦C. To prevent oscillations while solving, the temperature of air through the HVAC was updated every 50 iterations.Recirculation, which enhances the mixing of air inside the IP, was shown to decreasethe temperature of the ECU. The extent of this temperature reduction was foundto be influenced by the ambient temperature. Based on the understanding of theoperation of the HVAC system, it was concluded that the cooling performance ofthe ECU is critical in cold ambient conditions. It was observed that at an ambienttemperature of 0◦C, increasing the recirculation fraction from 0 to 0.8 reduced theECU’s maximum temperature by approximately 7◦C.Based on the study’s findings, several cooling strategies were proposed to improve thethermal management of ECUs. Utilizing the existing fan of the ECU to enhance themixing of air within the IP was shown to reduce the ECU’s temperature by around5◦C. While, incorporating an additional fan provided an even greater reduction,lowering the temperature by approximately 8◦C.