Research on Solar Thermal Energy Warming Diesel Engine Based on Reverse Heat Transfer of Coolant

In winter, the temperature of the coldest month is below -20°C. Low temperature makes it difficult to start a diesel engine, combust sufficiently, which increases fuel consumption and pollutes the environment. The use of an electric power-driven auxiliary heating system increases the battery load and power consumption. Solar thermal energy has the advantages of easy access, clean and pollution-free. The coolant in the cylinder block of the diesel engine has a large contact area within the cylinder and is evenly distributed, which can be used as a heat transfer medium for the warm-up. A one-dimensional heat transfer model of the diesel engine block for the coolant warm-up is developed, and the total heat required for the warm-up is calculated by an iterative method in combination with the warm-up target. According to this paper, the matching calculation of the parameters and the development of the structural feature model of the heat storage device, the heat transfer element, and the solar collector will be presented. The heat energy collected by the solar collector is stored in the heat storage device through the heat transfer element. Before starting the engine, the heat energy in the heat storage device is released to heat the coolant. The coolant is circulated between the cylinder block and the heat storage device to warm up the diesel engine. The results show that the temperature of the diesel engine can be more than 7°C higher than the ambient temperature after the engine is warmed up. This project can improve the temperature of the diesel engine when starting and provide a reference for solving the problem of a diesel engine starting in cold areas with abundant sunshine.