Design and Simulations of an Enhanced and Cost Effective Engine Split Cooling Concept

The ongoing global trends in engine downsizing and continuous need for higher engine specific output require more heat to be transferred out of the engine and into the radiator. This higher heat rejection necessitates higher coolant flow rate which is often accompanied with higher water pump power consumption and increased coolant circuit's cavitations risk. An enhanced split cooling concept is proposed to overcome the stated limitations with more efficient and effective coolant distributions to the cylinder head and cylinder block. The proposed concept also enables the cylinder head to run cooler than the cylinder block without the need for additional thermostat or water pump. The temperature differences are achievable by optimizing the coolant flow rates going through the cylinder head and cylinder block using both the 1D and 3D simulation packages. From the iterations conducted, an optimum flow distribution ratio is identified for a typical 1.3 liter naturally aspirated engine, together with the optimum cross section opening areas at both the cylinder head and cylinder block. From the simulation results, the proposed concept also achieves better coolant flow velocity at the cylinder head thus enabling better cooling of hot spots at the exhaust valve bridges and around the spark plugs. In addition, the proposed concept achieves higher coolant flow rate going to the radiator. This paper also discusses the motivations, design parameters, simulation methods, advantages and future outlooks of the proposed cooling concept.