Friction reduction: another route to fuel economy
A reduction of seven kPa (one psi) in friction mean effective pressure produces one to two percent fuel economy improvements in typical four-cylinder engines. At the typical engine speed of the EPA CVS metro-highway driving cycle, major motoring friction components are pistons/rings, valve train, crankshaft, and oil pump. Ring tension and geometry changes as well as roller tappets and reduced valve spring loads can lessen friction losses. Reduced gear diameter and drive ratios for oil pumps lower parasitic friction losses. Although individual friction components have only small fuel economy influences, their quantification provides guidance for future research and development toward improved performance.
- OSTI ID:
- 6387133
- Journal Information:
- Automot. Eng.; (United States), Vol. 90:5
- Country of Publication:
- United States
- Language:
- English
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