Evaluation of hot water storage strategy in internal combustion engine on different driving cycles using numerical simulations

Abstract

Since the main interest worldwide of green environment companies is to reduce pollutant emissions, the automotive industry is aiming to improve engine efficiency in order to reduce fuel consumption. Recently, studies have been shifted from upgrading the engine to the auxiliary systems attached to it. Thermal management is one of the successful fields that has shown promise in minimizing fuel consumption and reducing pollutant emissions. Throughout this work, a four-cylinder turbocharged diesel engine model was developed on GT-Power. Also, a thermal code has been developed in parallel on GT-Suite, in which the different parts of the coolant and lubricant circuits were modeled and calibrated to have the best agreement with the temperature profile of the two fluids in the system.

Once the model was verified, hot coolant storage, a thermal management strategy, was applied to the system to assess the fuel consumption gain. The storage tank was located downstream the thermostat and upstream the radiator with three valves to control the coolant flow. The place was chosen to avoid negative impact on the cold start-up of the engine when the tank is at the ambient temperature. This strategy was applied on different driving cycles such as the NEDC, WLTC, CADC (urban and highway), and an in-house developed driving cycle. The ambient temperature was varied between −7°C to represent the coldest winter and 20°C. The results of this study summarize the ability of the hot coolant storage strategy in reducing the fuel consumption, and show the best driving cycle that needs to be applied on along with the influence of the different ambient temperatures.