Comprehensive Thermal Modeling of Power Split Hybrid Power-Train and Electronics.

Hybrid electric vehicle (HEV) uses both internal combustion engine (ICE) with an electric system. The combination of the electric power train with the ICE is intended to achieve both better fuel economies than the conventional vehicles and better performance. Several types of HEV exist with different layouts. Recent HEVs' make use of regenerative braking, which converts the vehicles' kinetic energy into electric energy instead of wasting it as heat as conventional brakes do. A hybrid-electric is more fuel efficient than ICE and has less environmental impact.The new HEV with its new Key Characteristics and Configurations (i.e. Mechanical complexity, Multiple driving modes, Multiple prime movers, ... etc) inflict an interference with the existed thermal management system of the conventional vehicles, which leads to a new thermal management issues that should be addressed to enhance the performance of such systems. There is no complete knowledge in the open literature about the thermal management issues of HEV yet.This dissertation introduces Comprehensive Thermal Modeling of Hybrid Vehicular systems to assist monitoring the added-on of hybrid modules into the vehicle thermal management system. The model proposes a combined experimental and finite differencing nodal net work simulation modeling approach; using Thermography detectors calibrated for emissivity to capture 2-D spatial and transient temperature measurements. The Thermographic detectors were deployed through dual band thermography to neutralize the emissivity and to provide different dynamic ranges to achieve accurate temperature measurements. A thermocouples network was installed to provide a reference signal.A new comprehensive 3-D thermal model was developed by generating 3-D surface description for a complete hybrid electric vehicle from 3-D scans of an actual vehicle to guarantee the quality of the surface geometry, and break down the surfaces of the model into finite elements to improve the accuracy for better thermal analysis. The boundary conditions from a vehicle under different driving modes and load scenarios were deployed into the finite differencing simulation which was performed using finite differencing code capable of solving a sophisticated thermal/fluid systems with minimal user interaction (RadTherm) to provide a 3-D Thermal predictions and an Image Viewer (wireframe and animated thermal display).The 3-D model assisted monitoring the adding of Hybrid modules into the vehicle thermal management system and was used to analyze packaging considerations and integrating different modules for Hybrid Vehicles. In addition to the design of alternative materials for hybrid modules and Battery Packs for better thermal management; the model assisted studying the influence of applying different cooling methodologies and evaluate its effect on the thermal performance of the HEVs' power trains. A spatial and a transient temperature profiles obtained from the simulation for different components were compared with experimental results in order to validate the complete thermal model.Keywords: Hybrid electric vehicles, Power train, Power split, Battery packs, Power electronics, Drive cycles, Thermal management, Thermal modeling.