Effect of fuel and lubricant composition on engine deposit formation
All primary chemical reactants, including fuel, base oil, lubricant additives and air, were evaluated and considered as possible sources or causes of deposits. Tendencies of deposit formation could be determined in a 48-hour test using a modified single cylinder CLR oil test engine under conditions which had been found to give a high blow-by rate and produce a crankcase atmosphere rich in nitrogen oxides and incompletely burned or raw fuel. In the engine tests of this study, incomplete combustion of fuel was found to contribute more to deposits than decomposition of lubricant. Olefins caused heavier deposits than other types of fuel hydrocarbons. Deposits were formed in oxidations and condensations where nitrogen oxides acted as radical initiators but the structure and elemental composition of the polymeric deposits showed that low molecular weight carbonyl compounds in blow-by are more readily included in their formation than nitrated intermediates. The crankcase oil is a reaction medium for the blow-by components. The oxidatively stable synthetic oils minimized varnish but esters accumulated much more pentane-insolubles than polyalphaolefins or alkylbenzenes. The relatively less stable mineral oils are mixtures of many different hydrocarbon types, where the oxidative stability is determined by the least stable components. They reacted first and promoted further oxidation. Consequently, a used oil may be considered to consist of a small amount of less stable hydrocarbons which have been oxidized and a bulk of relatively stable unchanged hydrocarbons. Thus, used oils could be purified, distilled and hydrofinished to give recycled oils which were oxidatively more stable than the virgin 240 neutral mineral base oil.
- Research Organization:
- Gulf Research and Development Co., Pittsburgh, PA
- OSTI ID:
- 6545328
- Report Number(s):
- CONF-810308-(Vol.2)
- Journal Information:
- Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States), Vol. 26:2; Conference: American Chemical Society symposium on the chemistry of engine combustion deposits, Atlanta, GA, USA, 29 Mar 1981
- Country of Publication:
- United States
- Language:
- English
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02 PETROLEUM
AUTOMOTIVE FUELS
CHEMICAL ANALYSIS
DEPOSITS
INTERNAL COMBUSTION ENGINES
LUBRICATING OILS
ADDITIVES
ALKENES
COMBUSTION
HEPTANE
MINERAL OILS
NITROGEN OXIDES
PERFORMANCE TESTING
RECYCLING
TOLUENE
WASTE OILS
ALKANES
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
ENGINES
FUELS
HEAT ENGINES
HYDROCARBONS
LUBRICANTS
NITROGEN COMPOUNDS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
TESTING
THERMOCHEMICAL PROCESSES
330100* - Internal Combustion Engines
025000 - Petroleum- Combustion