ASTM D5797 Standard Specification for Fuel Methanol (M70-M85)
ASTM D5797 Standard Specification for Fuel Methanol (M70-M85) for Automotive Spark-Ignition Engines
4. Fuel Methanol (M70-M85) Performance Requirements
4.1 Fuel methanol (M70-M85) shall conform to the requirements in Table 1.
NOTE 1 - Most of the requirements cited in Table 1 are based on the best technical information currently available regarding the performance of these fuels in current technology vehicles. Requirements for sulfur, phosphorus, and lead are based on the use of gasoline defined in Specification D4814 understanding that control of these elements will affect catalyst lifetime. The lead maximum is limited for Class 1 and Class 2 fuels to the lower limit of the test method. As greater experience is gained from field use of M70-M85 vehicles, and further vehicle hardware developments for the use of higher methanol content fuels occurs, it is expected that many of these requirements will change.
4.1.1 Vapor pressure is varied for seasonal and climatic changes by providing three vapor pressure classes for M70-M85. The seasonal and geographic distribution for the three vapor pressure classes is shown in Table 2. Class 1 encompasses geographical areas with 6-h tenth-percentile minimum ambient temperature of greater than 5°C (41°F). Class 2 encompasses geographical areas with 6-h tenth-percentile minimum temperatures of greater than -5°C (23°F) but less than +5°C. Class 3 encompasses geographical areas with 6-h tenth-percentile minimum ambient temperature less than or equal to -5°C.
4.1.2 The hydrocarbons used shall have a final maximum boiling point of 225°C (437°F) by Test Method D86, oxidation stability of 240-min minimum by Test Method D525, and No.1 maximum copper strip corrosion by Test Method D130. The hydrocarbons may contain aliphatic ethers as blending components as are customarily used for automotive fuel.
4.1.3 Use of unprotected aluminum in fuel methanol (M70-M85) distribution and dispensing equipment will introduce insoluble aluminum compounds into the fuel causing plugged vehicle fuel filters. Furthermore, this effect can be exaggerated even with protected aluminum by elevated fuel conductivity caused by contact with a nitrile rubber dispensing hose. Therefore, unprotected aluminum and an unlined nitrile rubber dispensing hose should be avoided in fuel methanol (M70-M85) distribution and dispensing systems.
