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Past oil consumption reduction efforts were motivated by operating cost, petroleum conservation, or customer quality perception concerns. Recent efforts have been driven by exhaust catalyst poisoning considerations. The need to certify emissions to a higher mileage level and optimization efforts on the emission control systems have resulted in higher objectives for oil control. This paper focuses on one important factor in the control of lubrication oil consumption in internal combustion engines. Previous studies have related bore finish to oil consumption through either theoretical or experimental techniques. In this study, a mathematical model is derived statistically from experimental data utilizing regression analysis and a new transient radiotracer oil consumption measurement technique. The model predicts oil consumption levels expected with variations in cylinder bore finish, and suggests the important surface finish parameters to specify and control for minimum oil consumption.

A new automobile diesel engine concept has been developed to the preliminary engine design level and demonstrated by simulating vehicle tests with a computer model using steady state engine dynamometer data. The preliminary design is a six cylinder, swirl chamber diesel of 209 CID and 130 GHP. This concept engine weighs 495 pounds and employs turbocharging, variable compression ratio, high prechamber-main chamber volume ratio and exhaust gas recirculation. An existing automobile diesel was modified to simulate the concept engine and steady state engine tests were conducted. Test results were converted to urban cycle results for a 3000 pound GVW vehicle through the use of a computer model. Emission results (Grams/Mile) are .21 NOX, .24 HC, and 1.24 CO. Fuel consumption (Miles/Gallon) is 30.3 urban cycle and 36.4 highway cycle. Vehicle cycle results at 3700 pounds GVW meet all emission requirements and exceed the future 27.5 MPG requirement by ten percent.