LUBRICANTS FOR HIGHLY TURBOCHARGED DIRECT-INJECTION DIESEL ENGINES

A laboratory engine test procedure was employed to develop lubricants suitable for highly turbocharged diesel engines in response to three significant areas of legislation for truck manufacturers in Europe which have affected engine design and placed more stringent requirements on lubricants. These areas include maximum gross vehicle train weight (GVTW), minimum brake horsepower per ton of GVTW, and maximum smoke emission. European legislative pressures and a market demand for low fuel consumption have led to the development of turbocharged direct-injection diesel engines with brake mean effective pressure ratings in excess of 160 psi for truck operation. This trend has resulted in increased field problems involving high oil consumption and ring seizure due to cylinder wear or bore polishing. The Ford Tornado truck engine was used in laboratory testing of two reference oils and two candidate oils. A series of new candidate lubricants was devised using the Ford Tornado engine test procedure, and typical results obtained with commercial, reference, and candidate oils are tabulated. Additive packages developed to control bore polishing have been extensively engine tested to assure they will meet all other aspects of diesel crankcase oil performance. Field testing in highly turbocharged diesel engines is in progress as a final demonstration of performance.