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To reduce parasitic losses, a project was initiated to design, develop and bring to production a piston ring set which reduces engine friction while maintaining ring performance. In this paper, theoretical considerations affecting piston ring friction, and their implication in ring design, are discussed. An estimate of friction reduction and fuel economy improvement which can be achieved is calculated. Features of the resulting designs are reviewed, and friction, dynamometer, and vehicle test results are presented. Future ring design changes for reduced friction are reviewed.

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.