Silent operating range of military electric hybrid vehicle using electric power splitter and different electric energy storage

Abstract

Paper deals with operating range of hybrid car using electric power splitter and battery or super capacitor under special military condition. Special attention is paid to military vehicles having a duty to move in defined territory without using the combustion engine. Reason of this demand is to move without doing noise. It is reasonable to use under this condition only the electric drive and energy stored in the battery or super capacitor. The paper simulates in the given terrain and on basis of the given driving cycle that is velocity against time the ability of different storage systems to fulfil these demands. Mass of the vehicle is 2000kg. Mass of the battery respectively mass of the super capacitor is the same 70kg. The energy density in the battery is 150Wh/kg and the energy density in the super capacitor is 25Wh/kg. That means that energy stored in the battery is 10.5kWh at chosen rated voltage 240V. Energy stored in the super capacitor is 1.75kWh at maximum rated voltage also 240V. The 80% energy from battery or 75% energy from the super capacitor can be used for traction. The power of internal combustion engine (ICE) is controlled by a special program taking in account good efficiency of the engine, instantaneous acceleration, instantaneous power flow from the energy sources to vehicle wheels taking in account losses and instantaneous energy stored in battery or super-capacitor. The ICE is controlled in modus "stop and go". In "dangerous" region it is stopped totally. The traction power is taken partially from the ICE and partially from the battery or super capacitor. Sharing of these two power sources is controlled by the program. The lowest energy level in the battery may be 2,1 kWh and in super capacitor 0,55kWh.