The technology has been developed which will allow manufacturers to produce cars capable of running on methanol/gasoline blends with a methanol content up to 85% (i.e., M85). These cars will operate on varying methanol/gasoline ratios without any adjustments from the driver. The dual-fuel capability is attractive since vehicle use will not be handicapped by a restricted fuel distribution system. In addition, it provides the option of running on an environmentally “cleaner” fuel where it is available.
The advent of fuel-flexible vehicles encourages the development of lubricants which will satisfy the demands of both fuels. The unique properties of methanol, however, increase the challenges of meeting the lubricant performance needs.
Field and engine dynamometer testing have been aimed at understanding the response of key lubricant variables with M85. Short-trip, cold-weather conditions have been of particular concern. Direct comparisons of M85 with gasoline fueling under severe conditions demonstrate the differences in the lubrication demands of the two fuels.
Testing shows that a lubricant which provides acceptable protection with gasoline fueling may not be adequate with M85. Rusting and associated problems appear to be the most critical issue. Cylinder bore and ring wear are of less concern.
Current API gasoline engine lubricant specifications do not define the needs of M85. However, they do not exclude the potential for improvement with M85. Testing in a laboratory engine rust test converted to M85 from leaded gasoline, only partially relates to field performance.