Fully optimized energy management for propulsion, thermal cooling and auxiliaries of a serial hybrid electric vehicle

Abstract

Energy management in vehicles is a relevant issue, especially in the case of electric vehicles (EV) or hybrid vehicles (HEV) where different energy demands have to be satisfied from the primary energy source.In this work two energy management strategies are applied to a serial hybrid High Mobility Multipurpose Wheeled Vehicle in order to analyze the potentiality of the reduction of fuel consumption. A one-dimension numerical model of the serial hybrid vehicle was established. This model integrates hybrid vehicle propulsion, internal combustion engine cooling, electric engine and appliances cooling and energy consumption from auxiliary equipment. All the energy required for the vehicle comes from the internal combustion engine that is coupled to a generator. This injects energy to constant electrical tension into the power bus that can be stored in batteries and ultracapacitors or feed to the propulsion engines and the auxiliaries. Electrical storage systems can also inject energy into the power bus to satisfy any demand. The cooling system is integrated by radiators, electrically controlled pumps, fan and valves and all the equipment present a maximum allowable outlet water temperature that cannot be passed. Vehicle propulsion loads and ambient air conditions have been estimated from a route usually followed by ground troops where position, velocity and acceleration are available.Based on the previous model, two control strategies for the combined control of propulsion, cooling and auxiliaries' energy supply were proposed and evaluated. As a result and considering the expected useful life of the vehicle, the best energy management strategy is able to avoid the consumption of more than 50,000 L of diesel fuel avoiding the emissions of 177 tons of CO2.