On the Concept of Separate Aftercooling for Locomotive Diesel Engines

This paper describes a patented cooling system concept for a turbocharged diesel engine. In particular, it defines a cooling system having the capability of transferring some of the cooling capacity of engine jacket and engine oil cooling to cool the cylinder inlet air when more than the cooling capacity built into the system through the size of the radiators and fans is needed. This increased aftercooling will improve the engine performance and reduce emission levels. The cooling capacity of a locomotive is essentially determined by the radiator and fan size, among other factors, and is designed to cool the engine within acceptable metal temperatures at a specified maximum ambient temperature and at the maximum engine power. On the other hand, at lower ambient temperatures or engine power levels, the cooling needs of the engine will be less than this maximum cooling capacity of the cooling system. There remains some excess capacity. This paper describes the concept called the “Separate Aftercooling System” that uses some of this excess cooling capacity to cool the engine inlet air at the aftercoolers. It shows the feasibility of such a system, describes the order of magnitude of benefits that can be expected from such a system, and outlines the implementation of this concept to EMD built Locomotives.