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Review and Evaluation of Lubricated Wear in Simulated Valve Train Contact Conditions
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Abstract
The development of cross-flow single overhead camshaft designs of engines led to the introduction of pivoted cam followers with pads that were subjected to uni-directional rolling/sliding under heavy contact loads. Such components were prone to wear failure by a mechanism involving severe surface roughening. The initiating wear mechanism was eventually shown to be a form of “mild” wear and the Archard wear equation was used successfully to model the pattern of wear seen on cams and followers.
The use of rigs to assess the wear performance of different lubricants has hitherto been a very poor predictor of engine performance, because of the complex interaction of materials, kinematics and forces in real engines. As a result, most automotive lubricant development relies on engine testing, which is expensive and time-consuming. Also, the complexities of the engine environment make it difficult to obtain much scientific insight into the tribological processes involved. The latter problem has been tackled by developing a rig test that simulates key features of a valve train system in a controllable manner.
The test is based on the use of a highly modified twin-disc Amsler test machine, with one disc replaced by a reciprocating block to simulate the kinematics of valve train systems. This test has been used to evaluate the wear performance of the industry standard reference oils for the Peugeot TU3 valve train test. The wear data obtained in the Reciprocating Amsler test correctly ranked the two oils over a range of loads. Furthermore, the test successfully reproduced the patterns of wear, surface topography and surface film formation seen on cam followers from engine tests.
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Roper, G. and Bell, J., "Review and Evaluation of Lubricated Wear in Simulated Valve Train Contact Conditions," SAE Technical Paper 952473, 1995, https://doi.org/10.4271/952473.Also In
References
- Bell J.C. “Engine Lubricants” Engine Tribology Taylor C. M. Elsevier 1993 287 301
- Bell J.C. Colgan T.A. “Critical physical conditions in the lubrication of automotive valve train systems” Tribology International 24 2 April 1991 77 84
- Dyson A. “Kinematics and wear patterns of cam and finger follower automotive valve gear” Tribology International 13 3 June 1980 121 132
- Bell J.C. “Reproducing the kinematic conditions for automotive valve train wear in a laboratory test machine” Journal of Engineering Tribology
- Coy R.C. Dyson A. “A rig to simulate the kinematics of the contact between cam and finger follower” Lubrication Engineering 39 3 Mar 1983 143 152 ASLE/ASME Lubrication Conference New Orleans, Louisiana Oct 5-7 1981
- Bell J.C. Delargy K.M. Seeney A.M. “The removal of substrate material through thick ZDTP anti-wear films” Wear Particles Dowson D. et al Elsevier 1992 387 396
- Willermet P.A. Dailey D.P. Carter R.O. III Schmitz P.J. Zhu W. Bell J.C. Park D. “The composition of lubricant-derived surface layers formed in a lubricated cam/tappet contact: II. Effects of adding overbased detergent and dispersant to a simple ZDTP solution” Tribology International
- Yin Z. Kasrai M. Bancroft G.M. Laycock K.H. Tan K.H. “Chemical characterization of anti-wear films generated on steel by zinc dialkyldithiophosphate using X-ray absorption spectroscopy” Tribology International 26 6 1993 383 388
- Colgan T.A. Bell J.C. “Modelling valve train wear for cycling conditions” Proc. Japan International Tribology Conference Nagoya 1990 1231 1235
- McGeehan J.A. Yamaguchi E.S. “Gasoline-engine camshaft wear - the culprit is blow-by” SAE paper 892112 1989
- Institute of Petroleum Standard Methods for Analysis of Petroleum and Related Products 1994 Wiley 1994
- Archard J.F. Contact and rubbing of flat surfaces” J. Appl. Phys. 24 1953 981
- Samuels B. Richards M.N. “The transition between mild and severe wear for boundary lubricated steels” Journal of Tribology 113 Jan 1991 65 72