Engine and MG driving power control of HV in engine warm-up period avoiding fuel economy deterioration and reducing warm-up time

Abstract

In order to improve fuel consumption, conventional HV (Hybrid Vehicle) control has intended to reduce exhaust heat power from engine and transform fuel into driving power as much as possible. However it causes deterioration of fuel consumption when engine exhaust heat is necessary like the condition that engine is warming up or heat power for cabin is supplying in winter. In this paper, engine and MG (Motor & Generator) driving power control of HV in engine warm-up period avoiding fuel economy deterioration and reducing warm-up time by balancing coolant temperature and SOC (State Of Charge) of battery is proposed. The principle of control is predictive control with HV model including engine, MG, battery and coolant characteristics. Engine and MG power, control manipulation value, are decided as minimizing cost function including warm-up time and fuel amount. As a result of verification with simulation, the proposed control achieves notable effect especially at the condition that small SOC margin is remained for its upper limit. In such a condition, conventional control keeps engine working until warm-up is completed in order not to stop supplying heat power for coolant, however the proposed control stops it as needed based on the balance of SOC and coolant temperature, and reduce warm-up time and fuel consumption.

Keywords

• automotive control
• hybrid vehicle
• predictive control
• energy management
• engine control