Characterizing the effect of viscosity on friction in the piston assembly of internal combustion engines

Abstract

The friction mean effective pressure (fmep) contribution of piston assemblies running under motored engine conditions in cylinders with plateau or laser honed bores has been investigated. Results have been obtained for engine speeds in the range 400-2000 r/min and temperatures from -20 to around 60°C. The fmep of the piston assembly is observed to depend most directly on oil viscosity evaluated at the temperature of the cylinder wall at mid-stroke position. The variation of fmep with viscosity provides a basis for comparing the effects of surface finish or piston design modifications. Using liners with fine honed bores reduced piston assembly friction by between 3 and 20 per cent relative to results for pistons running in plateau honed bores. Piston assembly friction was reduced by between 5 and 38 per cent through design changes to the pistons.

Keywords

piston assembly friction oil viscosity

Get full access to this article

View all access options for this article.

References

Manni

Gommellini

Sabbioni

Effect of physical characteristics of lubricating oils on emissions, fuel economy and oil consumption in a light duty diesel engine. SAE paper 952552, 1995.

Tseregounis

S. I.

McMillan

M. L.

Olree

R. M.

Engine oil effects on fuel economy in GM vehicles - separation of viscosity and friction modifier effects. SAE paper 982502, 1998.

Monaghan

M. L.

Engine friction - a change in emphasis

Proc. Instn Mech. Engrs, Part D: Transport Engineering, 1988, 202 (D4), 217–226.

McGeehan

J. A.

A literature review of the effects of piston and ring friction and lubricating oil viscosity on fuel economy. SAE paper 780673, 1978.

Furuhama

Tribology on reciprocating internal combustion engines

JSME Int. J., 1987, 30 (266).

Taylor

R. I.

Coy

R. C.

Improved fuel efficiency by lubricant design: A review

Proc. Instn Mech. Engrs, Part J: J. Engineering Tribology, 2000, 214 (J1), 1–15.

Taylor

R. I.

Lubrication, tribology and motorsport. SAE paper 2002-01-3355, 2002.

Heywood

J. B.

Internal combustion engine fundamentals, 1988 (McGraw-Hill, USA).

Shayler

P. J.

Leong

D. K. W.

Murphy

Contributions to engine friction during cold, low speed running and the dependence on oil viscosity

SAE Trans., J. Engines, 2005, 114, 1191–1201, SAE paper 2005-01-1654.

10.

Shayler

P. J.

Burrows

J. A.

Tindle

C. R.

Murphy

Engine friction characteristics under cold start conditions. 2001 Fall Technical Conference, ASME paper no. 2001-ICE-432, 2001, ICE-Vol. 37–3.

11.

Shayler

P. J.

Christian

S. J.

A model for the investigation of temperature, heat flow and friction characteristics during engine warm-up

SAE Trans., J Engines, 1993, 102, 1588–1597, SAE paper 931153.

12.

Burrows

J. A.

An investigation into the cold start performance of automotive diesel engines. PhD Thesis, University of Nottingham, 1998.

13.

Sorab

Holdeman

H. A.

Chui

G. K.

Viscosity prediction for multigrade oils. SAE paper 932833, 1993.

14.

Stachowiak

G. W.

Batchelor

A. W.

Engineering tribology, Vol. 24, 1993 (Elsevier, Amsterdam).

15.

Shayler

P. J.

Baylis

W. S.

Murphy

Main bearing friction and thermal interaction during the early seconds of cold engine operation. 2002 Fall Technical Conference, ASME paper no. ICEF2002-528, 2002, ICE-Vol. 39.

16.

Robota

Zwein

Einfluss der Zylinderlauf-flachentopografie auf den Olverbrauch und die Partikelemissionen eines DI-Dieselmotors. MTZ 60, 1999 (Vieweg Verlag, Wiesbaden).

17.

Jeng

Y. R.

Friction and lubrication analysis of a piston-ring pack. SAE paper 920492, 1992.