Numerical Investigation of Engine Thermal Encapsulation and Its Impact on Extended Range Electrical Vehicle (E-REV) Energy Consumption

Because electric vehicles (EVs) do not generate pollutants during usage, and they can potentially rely on energy provided by a selection of renewable sources, they are the focus of much current interest. However, due to the present capabilities of battery technology, the overall range of such a vehicle is limited. Furthermore, once the battery is depleted relatively long recharging times are currently required before the vehicle is available for use again. Extended range electric vehicles (E-REVs) overcome many of the short-comings of EVs by having a ‘range extender’ unit, which consists of an onboard electric generator powered by an internal combustion engine. In this type of powertrain, the engine configuration either used the spark ignition or compression ignition engines. The engine operation in cold-start conditions can have a significant impact on drivability, fuel economy and tailpipe emissions. After pure electric range, the engine must turn ON/OFF consecutively in range extended operation to charge battery module. During this stage, the engine thermal state is critically important to retain its performances. As efforts continue to maximize fuel economy in passenger vehicles, considerable engineering resources are being spent to reduce the consumption penalties incurred shortly after engine start and during powertrain warmup while maintaining suitably low levels of tailpipe emissions. This work seeks to explore the engine warming strategy during extended range operation by providing engine thermal encapsulation and to understand the resulting fuel economy impact relative to warm powertrain operation. A 1D/3D based integrated computational methodology is developed to evaluate the impact of engine thermal encapsulation on warming characteristics and its impact on E-REV energy consumptions. Additionally, the simplistic SOC based control strategy used understand the ON/OFF time taken during range extended operations for WLTP, and Artemis drive cycles.