Improvement in engine thermal management by changing coolant and oil mass

Abstract

Several investigations related to increasing engine thermal efficiency focusing on the engine hydraulic circuits (oil and coolant) were performed over the last years. According to literature, more than 20% of the fuel energy is rejected to the coolant in steady state conditions. Thus, better use of that energy, especially during warm up of the engine, would lead to an improvement of engine performance and fuel consumption. In the present work, a complete engine and its subsystems were modeled and validated in a 0D/1D in-house software. After, several case studies based on modifying the volume of the engine hydraulic circuits were simulated and analyzed. The simulations were performed for steady state and transient conditions. On one hand, the impact of the present thermal management strategy was practically negligible in steady state conditions. On the other hand, for transient conditions and ambient boundary conditions, the results showed that by reducing the coolant volume by 45% the reduction in warm up time and fuel consumption compared with the base case were 7% and 0.4% respectively. Additionally, for cold conditions, the impact was even higher, obtaining a reduction of warm up time and fuel consumption of 13% and 0.5% respectively.