Surface finish and composition dependence of valvetrain friction with silicon nitride tappet inserts
Surface finish and composition dependence of valvetrain friction with silicon nitride tappet inserts
- New search for: Crosbie, G.M.
- New search for: Allor, R.L.
- New search for: Gangopadhyay, A.
- New search for: McWatt, D.
- New search for: Wiliermet, P.
- New search for: Crosbie, G.M.
- New search for: Allor, R.L.
- New search for: Gangopadhyay, A.
- New search for: McWatt, D.
- New search for: Wiliermet, P.
To reduce automotive valvetrain friction losses, polished silicon nitride tappet inserts were tested for possible friction reduction. Silicon nitrides obtained from three sources were polished using diamond polishing and two non-diamond polishing techniques: chemomechanical polishing and 'Ford' finish. The valvetrain friction torque was determined in a laboratory apparatus using a single cam lobe rotating against a direct acting mechanical bucket tappet with production engine hardware. The friction torque values obtained differed substantially even though the initial average surface roughnesses were similar. Each of three silicon nitrides prepared with the 'Ford Finish' showed a lower friction torque than the production steel when an engine oil without a friction modifier was used. With a low friction oil, all torque values were lower and silicon nitrides did not offer much additional friction reduction benefit. A calculation showed a maximum of about 0.5% fuel economy benefit can be gained due to the substitution of certain polished silicon nitrides with the oil without modifier.
Document information
Surface finish and composition dependence of valvetrain friction with silicon nitride tappet inserts
1999
8 Seiten, 9 Quellen
Conference paper
English
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