Quote:
Accumulation of lead in ester-based engine oils
W. Baumann, K. Reiter, W. Zeiner
OMV AG, Schwechat, Austria
Keywords
ester-based • engine oil • lead • bearings • inhibitor • treat rates • Pb • Fe • older engines
Abstract
Synthetic esters are widely used as base-oil components in top-tier crankcase lubricant formulations. In combination with synthetic hydrocarbons, an ester content of between 10 and 50 wt.% is common. Only a few engine oils with an ester content above 85 wt.% have been introduced on to the market as yet. The use of such engine oils is advantageous, especially in environmentally sensitive areas, in terms of volatility, particle emissions, and biodegradability.
Some older types of heavy-duty diesel engine continue to be run in vehicles and in machinery in the construction industry, and in such engines a higher lead content has been detected when ester-based engine oils have been used. It has been found that lead is extracted from the bearings and accumulates ultimately in the engine oil during operation. Consequently, the development of a suitable inhibitor system has been initiated to improve engine and bearing protection. To determine the effectiveness of the new inhibitors, a suitable test method had to be found.
Using a test method based on the Petter WI (CEC L-02-A-78) test engine, the present paper summarises the results of tests on an inhibitor system to prevent lead extraction from bearings The metal contents reported in this paper were determined by ion conductive plasma atomic emission spectrometry.
