Thermal Management Development for a Dedicated Hybrid Engine 2024-01-2416
The high-efficiency dedicated hybrid engine (DHE) has led to increasingly complex challenges in engine thermal management. On one hand, the high compression ratio of up to 16:1 makes the engine more susceptible to knocking, necessitating meticulous thermal management to mitigate the potential sensitivity to metal temperature. On the other hand, extensive use of external cooled exhaust gas recirculation (EGR) helps reduce knocking and improve thermal efficiency, but it also raises temperature levels and requires additional cooling measures.
For the 1.5L DHE developed by SAIC Motor, a split cooling structure was employed in the engine cooling system design, with the cylinder head water jacket and cylinder block water jacket arranged in parallel and equipped with different coolant outlets. By utilizing a dual thermostat to control flow, this design allows for adjustable flow distribution, providing effective cooling to the cylinder head while reducing cooling to the cylinder block. The block thermostat can close the flow of the block water jacket before the water temperature reaches the opening temperature, enabling quick warming of the cylinder block.
Furthermore, an electric water pump was employed as an ideal solution for the DHE, eliminating the need for a front-end drive system. This helps reduce parasitic losses due to accessories and improve overall efficiency. As the primary driving source for coolant in the entire cooling system, the electronic water pump plays a crucial role in the overall thermal management system. Specialized control strategies and software have been developed to optimize its performance.
This paper presents the development of thermal management, including cooling system design and simulations, as well as test development. It also elaborates on the control strategy development for the electric water pump, which meets the requirements of the engine and vehicle under various environmental and operating conditions.
