Moray S. Stark,* John R. Lindsay Smith, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter M. Lee, Martin Priest School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK R. Ian Taylor Shell Global Solutions, Chester, CH1 3SH, UK Chris Booth, Simon Chung Infineum UK Ltd., Milton Hill, Abingdon, Oxfordshire, OX13 6BB, UK STLE 2006: Calgary 7 th - 11 th May 2006 Factors Affecting Lubricant Degradation in the Piston Assembly of Gasoline Engines Department of Chemistry

Moray S. Stark,* John R. Lindsay Smith, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter M. Lee, Martin Priest School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK R. Ian Taylor Shell Global Solutions, Chester, CH1 3SH, UK Chris Booth, Simon Chung Infineum UK Ltd., Milton Hill, Abingdon, Oxfordshire, OX13 6BB, UK STLE 2006: Calgary 7 th - 11 th May 2006 Factors Affecting Lubricant Degradation in the Piston Assembly of Gasoline Engines

 Physical Conditions  Lubricant Flow Rates and Residence Times in Piston and Sump  Chemical Conditions  Volatile Hydrocarbons / Aromatics Department of Chemistry Factors Affecting Lubricant Degradation in the Piston Assembly of Gasoline Engines

Engine Oil Stress Factor for Gasoline Cars R. I. Taylor, R. Mainwaring, R. M. Mortier, Engine Lubricant Trends Since 1990, Proc. I. Mech. E. Vol 219, Part J: J. Engineering Tribology, p 1-16, 2005 © BP Castrol

Engine : Ricardo Hydra Institute of Tribology School of Mechanical Engineering,The University of Leeds Department of Chemistry  Fuel Injected Gasoline Research Engine  Single Cylinder of Production GM Engine  0.5 litre Capacity

Lubrication of Engine P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Lubrication of Engine P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Lubrication of Engine Sump 1 Valve Train P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Lubrication of Engine Sump 1 Valve Train Sump 2 Piston Assembly Crank Shaft P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Lubrication of Engine Sump 2 Piston Assembly Crank Shaft P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Degradation of Lubricant Piston Assembly Sump P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Degradation of Lubricant S. Yasutomi, Y. Maeda and T. Maeda, Kinetic Approach To Engine Oil.2. Antioxidant Decay of Lubricant in Engine System, Ind. Eng. Chem. Prod. Res. Dev. 20 (1981) 536 Piston Assembly Sump Piston Sump

Piston Assembly R. Gamble, Influence of Lubricant Degradation on Piston Assembly Tribology, PhD Thesis, University of Leeds, 2002

Piston Assembly M. S. Stark, R. J. Gamble, C. J. Hammond et al., Measurement of Lubricant Flow in a Gasoline Engine, Tribology Letters, 19, 3, (2005)

Extraction of Oil from Top Piston Ring R. Gamble, Influence of Lubricant Degradation on Piston Assembly Tribology, PhD Thesis, University of Leeds, 2002

Extraction of Oil from Top Piston Ring P M Lee, M S Stark, J J Wilkinson, et al.,, Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Tribology, Leeds 2004, Trib. and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Oil Flow in Engine Small Volume Short Residence Time Large Volume Long Residence Time Flow Rate S. Yasutomi, Y. Maeda and T. Maeda, Kinetic Approach To Engine Oil.2. Antioxidant Decay of Lubricant in Engine System, Ind. Eng. Chem. Prod. Res. Dev. 20 (1981) 536 Sump Piston

Piston Assembly Residence Time : Method Sump Piston Add Marker to Sump S B Saville, F D Gainey, S D Cupples, M F Fox, D J Picken, SAE Technical Paper, International Fuels and Lubricants Meeting, Oct 10-13, 1988 Sample Lubricant from Piston Assembly

Piston Assembly Residence Time : Method 1-e -1  RingPac k S B Saville, F D Gainey, S D Cupples, M F Fox, D J Picken, SAE Technical Paper, International Fuels and Lubricants Meeting, Oct 10-13, 1988

Piston Assembly Residence Time : 60 sec M. S. Stark, R. J. Gamble, C. J. Hammond et al., Measurement of Lubricant Flow in a Gasoline Engine, Tribology Letters, 19, 3, (2005) Conditions : 1500 rpm, 50 % Load. Lubricant : XHVI TM 8.2 only

Piston Flow Rate: Method Small Volume Short Residence Time Large Volume Long Residence Time Flow Rate S. Yasutomi, Y. Maeda and T. Maeda, Kinetic Approach To Engine Oil.2. Antioxidant Decay of Lubricant in Engine System, Ind. Eng. Chem. Prod. Res. Dev. 20 (1981) 536 Sump Piston

Summary of Lubricant Oxidation Chemistry (Talk 2.30 this afternoon: Lubricant Fundamentals) Infrared Spectroscopy of Carbonyl Group Hydrocarbon Base Fluid Hydroperoxides Alcohols Carboxylic Acids Ketones Department of Chemistry

Comparison of Sump and Ring Pack Conditions : 2000 rpm, 50 % Load M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005)

M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005). Comparison of Sump and Ring Pack Conditions : 2000 rpm, 50 % Load

Calculation of Sump Residence Time M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Calculation of Sump Residence Time M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Calculation of Sump Residence Time M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Sump Residence Time : Effect of Engine Speed Conditions : Engine Speed rpm, Load 50 % M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Ring Pack Flow Rate : Effect of Engine Speed M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005). Conditions : Engine Speed rpm, Load 50 %

Conditions : Engine Load 33 – 75 %, Speed 1500 rpm Ring Pack Flow Rate : Effect of Engine Load M. S. Stark, J. J. Wilkinson, P. M. Lee, et al., Life Cycle Tribology, Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, Trib.and Interface Engin. Series, Elsevier, Amsterdam, ISBN , pp (2005).

Piston Assembly Residence Time  60 seconds Volume of Oil  1 cm 3 cylinder -1 Flow Rates Returning to Sump  1 cm 3 min -1 cylinder -1 Oil Loss  0.05 cm 3 min -1 cylinder -1 Sump Residence Time  20 hours litre -1 Summary of Lubricant Flow in Gasoline Engine M. S. Stark, R. J. Gamble, C. J. Hammond, et al.,Tribology Letters, 19, 3, (2005) M. S. Stark, et al., Proc. 31st Leeds-Lyon Symp. on Trib., Leeds 2004, ISBN , pp (2005).

Piston Assembly M. S. Stark, R. J. Gamble, C. J. Hammond et al., Measurement of Lubricant Flow in a Gasoline Engine, Tribology Letters, 19, 3, (2005)

Chemical Analysis of Lubricant Samples  Field Ionisation – Mass Spectrometry (FIMS)  Gas Chromatography – Mass Spectrometry (GC-MS) Department of Chemistry

Field Ionisation Mass Spectrometry  Mass Spectrum of Fresh Lubricant Department of Chemistry

Field Ionisation Mass Spectrometry  z = 2 : non-cyclic alkanes (fresh lubricant)  mass = 14n + z (n = no. of carbons) Department of Chemistry

Field Ionisation Mass Spectrometry  z = 0 : mono-cyclic alkanes (fresh lubricant) Department of Chemistry

Field Ionisation Mass Spectrometry  z = -2 : bicyclic alkanes (fresh lubricant) Department of Chemistry

Field Ionisation Mass Spectrometry  z = -4 : tricyclic alkanes (fresh lubricant) Department of Chemistry

Field Ionisation Mass Spectrometry  Top Ring Zone Lubricant Department of Chemistry

Alkyl carbons Alkyl Benzenes in Ring Pack Oil Hexadecane Ocatadecane (Internal Standards) Base Fluid

Alkyl carbons Alkyl Naphthalenes in Ring Pack Oil

Alkyl carbons and 4 Ring Poly Aromatic Hydrocarbons (PAHs)

FIMS – Volatiles in Top Ring Zone Lubricant  z = -6 : Alkyl Benzenes (Benzene  n = 5)  z = 2 : Alkyl Naphthalenes (Naphthalene  n = 9) Department of Chemistry

FIMS Aromatic Volatiles : Effect of Engine Load  Effect of Load: Alkyl Naphthalenes (z = 2)  1500 rpm Department of Chemistry

FIMS Aromatic Volatiles : Effect of Engine Load  Effect of Load: Alkyl Benzenes (z = -6)  1500 rpm Department of Chemistry

Conclusions  Lubricant Residence Times and Lubricant Flow Through Sump and Piston Measured  Lubricant in Piston Assembly Exposed to High Concentrations of Alkylated Aromatics  Alkylated Aromatics not from Fuel: “Soot Precursors” from Combustion Process  Alkylated Aromatics Dependent on Engine Conditions Increases with Engine Load Department of Chemistry

Future Work  Detailed Chemical Analysis of Piston Ring Lubricant  Construct Bench Top Reactor to Simulate Piston  Study Effect of Antioxidants in Gasoline Engines Moray Stark

Future Work  Detailed Chemical Analysis of Piston Ring Lubricant  Construct Bench Top Reactor to Simulate Piston  Study Effect of Antioxidants in Gasoline Engines Acknowledgements  Roy Mortier for slide 3 (Engine Oil Stress Factor)  Trevor Dransfield (University of York) for GC-MS Financial Support  Shell Global Solutions, Infineum, EPSRC Moray Stark

Factors Affecting Lubricant Degradation in the Piston Assembly of Gasoline Engines (Abstract for STLE 2006: Calgary 7th- 11th May 2006) Moray S. Stark*, John R. Lindsay Smith, Julian J. Wilkinson Department of Chemistry, University of York, York YO10 5DD, UK Peter M. Lee, Martin Priest School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK R. Ian Taylor Shell Global Solutions, Shell Research Ltd, PO Box 1, Chester, CH1 3SH, UK Chris Booth and Simon Chung Infineum UK Limited, PO Box 1, Milton Hill, Abingdon, Oxfordshire, OX13 6BB, UK Lubricant extracted from the piston assembly of a gasoline engine has been chemically analysed to determine the level of degradation and the level and type of volatile carbon containing species. Using FIMS, the oil samples contain a noticeable amounts of volatile hydrocarbons, with molecular masses ranging from the fuel-sized to lubricant-sized molecules, and GC-MS reveals that they are alkyl benzenes and alkyl polyaromatic hydrocarbons; species of interest because they are both reactive and toxic. The effect of these species on the viscosity of the lubricant and the mechanism of their formation are discussed. One factor that controls the oil drain intervals of automotive engines is how fast it flows through the piston assembly, where it is subjected to high temperatures and corrosive blow-by gases, and returns degraded to the sump. Building on previous work, this flow rate has been measured, and its dependence on engine load and speed established. * Biography for Presenting Author The presenting author has a BSc and PhD in Physics, but has been working as a Chemist for longer than he can remember. The past few years have been spent specialising in the study of the oxidation mechanisms of hydrocarbon and ester lubricant base fluids and the effects that oxidation has on the rheology of lubricants.

FIMS Aromatic Volatiles : Sump vs. Piston  Sump at 40 hours vs. Ring Pack  1500 rpm : Alkyl Naphthalenes (z = 2) Department of Chemistry