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Effect of metal‐free phosphorus anti‐wear compounds on passenger car emissions and fuel economy
Author(s) -
Devlin Mark T.,
Guevremont Jeffrey,
Sheets Roger,
Loper John,
Guinther Greg,
Thompson Karen,
Jao TzeChi
Publication year - 2007
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.44
Subject(s) - phosphorus , automotive engineering , environmental science , waste management , business , chemistry , engineering , materials science , metallurgy
Abstract There has been concern for many years that phosphorus (P) from engine oils is volatilised, passes through the combustion chamber and is deposited on the catalyst system in passenger cars, causing the emission control system to lose efficiency. Therefore, as new engine oil specifications have been introduced, there has been a trend to require a reduction in P in fresh engine oils. The primary P source in current engine oils is zinc dithiophosphate (ZDP), which acts as an anti‐wear agent and antioxidant. Therefore, a reduction in P in the oil could compromise the anti‐wear and antioxidant performance of engine oils. Another detrimental effect of ZDP is that it is known to increase friction in the mixed lubrication regime, which in turn would decrease the ability of engine oils to improve fuel economy. Metal‐free P‐containing anti‐wear additives (MFPAWs) have been used for many years in other automotive and industrial lubricants. We examined the effect of an MFPAW in catalyst efficiency and fuel economy engine tests. Catalyst protection and the fuel economy benefits of engine oils were improved when the MFPAW was used in place of ZDP. Therefore, the total P content of an engine oil does not need to be reduced if the proper anti‐wear additive is selected. Copyright © 2007 John Wiley & Sons, Ltd.