A Method to Calculate the Energy Impact of Interactions between Vehicle Subsystems 2019-01-5036

In connection with the increasing energy and environment challenges, the automotive industry has been investing heavily on improving the energy efficiency of vehicles. Although the electrification of powertrain is the principal path towards reducing fossil fuel dependency, a greater understanding of the fuel energy utilisation on the vehicle (here intended as a ‘system’) is necessary to identify the readily available opportunities for efficiency improvements and ultimately develop cars which are more energy efficient. The energy efficiency or loss map of a vehicle’s components is often obtained experimentally from test rigs. The impact of any change in the efficiency or loss maps of a component on the other components of the vehicle and the total energy losses should be examined in the vehicle system level. In this article, a systematic approach is used to study the interrelation between the component losses and the total vehicle energy loss. A new method is proposed to determine a component energy loss due to its position in the energy flow from the energy source (the battery or fuel tank) to the energy sink (the energy demanded at the wheels). The method calculates the energy impact, the interaction energy effect of the vehicle’s components. It is shown that the components have no control over the portion of their losses related to inefficiencies of other components and also can benefit unreservedly from any improvement/loss reduction of other components. The new method is implemented to set and cascade the vehicle energy target to the components in order to drive accountability for energy consumption into subsystems/components.