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Ignition-improved methanol can be used as a fuel for heavy-duty diesel engines. However, endurance tests have revealed several fuel-related durability problems. Serious cavitation-induced erosion was observed in the injection system and extremely hard ceramic-like combustion deposits caused significantly increased wear. Since solutions could be found for most of the problems encountered, the technical viability of ignition-improved methanol can be considered as sufficiently proven. However, further development work will have to be done to modify engine parts and materials and to adjust properties of lubricating oil to the requirements of operation on methanol fuel.

A fuel blend containing 20% so-called ‘propanol-plus’ and 80% SASOL diesel was tested in a 4-cylinder direct-injection diesel engine. The propanol-plus, a mixture of 47% propyl alcohol and 53% higher alcohols, is a by-product of the SASOL fuel-from-coal process, and it would be of tremendous advantage if it could be blended ‘on-the-spot’ with the diesel produced by SASOL. Performance results with standard injection pump settings indicated that in comparison with operation on pure diesel, operation on the propanol-plus/diesel blend reduced the power by roughly 5% throughout the speed range. In addition, the volumetric fuel consumption was increased by, on average, 5.5% throughout the speed and load ranges. Despite the harsh combustion conditions created by the poor ignition quality of the propanol-plus/diesel blend, the engine successfully completed 300 hours of a particularly severe durability cycle.