Lubrication Studies in a Methanol-Fueled Spark Ignition Engine 892156

Methanol continues to be an important alternative fuel candidate for use in spark ignition engines. In addition to its potential as an alternative energy source, methanol has been claimed to provide benefits in possibly reducing reactive hydrocarbon emissions which contribute to ozone formation. This has resulted in considerable interest in using methanol fuels in several U.S. urban areas to assist in air pollution reduction. As a result of government incentives on these issues, engine builders are now developing new generations of vehicles capable of operating on methanol. Lubrication of these engines will require methanol-compatible oil formulations. Test work has shown that some current quality engine oils, designed for use with gasoline fuel, severely limit engine durability due to excessive wear of the valve train, cylinder bore, and bearings. A laboratory engine test program using a 2.3-liter engine has been conducted to evaluate methanol-fueled engine lubrication. After establishing the performance of selected reference oils, alternate formulations have been developed providing satisfactory wear protection. Oil formulations using synthetic base stocks offer important advantages for an all-seasons oil tailored for use in methanol-fueled engines. A severe over-the-road field test focusing on short-trip, cold-start operation using a methanol-fueled vehicle was conducted to demonstrate the performance of a synthetic product developed for use with methanol fuel.

METHYL ALCOHOL, or methanol, represents one of the most promising alternative fuels available today for use in current spark ignition internal combustion engines. Methanol can be made available from alternate energy sources, such as coal, natural gas, and/or organic biomass materials. In addition, methanol offers the potential for possibly reducing reactive vehicle hydrocarbon emissions which contribute to ozone formation. Methanol is also particularly attractive compared to other alternate fuels in that it can be used in current engine designs with minimal conversion effort and cost. As a result of these factors, interest and research into the use of methanol has been pursued by engine manufacturers, commercial vehicle operators, and government energy and environmental agencies.

The use of methanol in current engine designs presents lubrication requirements substantially different than those of conventional gasoline fuels. This has led to continuing studies on the effects of methanol by many researchers (1, 2, 3, 4, 5, 6 and 7, 10, 11, 12, 13, 14, 15 and 16).∗ As has been demonstrated by this prior research, using methanol as a fuel generally promotes a cleaner lubricant environment but also induces significantly greater engine wear compared to gasoline. This wear affects engine operation and durability. However, optimized lubricant formulations can provide acceptable engine performance with methanol as demonstrated in the following laboratory engine and field testing.