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Lubricity testing of reformulated diesel fuels (sulfur <0 005 w-%, aromatics <20 vol-%) was started in 1990. A 1000 hour in-house test rig with distributor pumps was used for testing fuels and additives. When lubricity is not adequate, excessive wear is seen in the pump. A field test on 140 buses each accumulating 150 000 - 250 000 km with reformulated diesel was carried out. Reformulated diesel has been on the market since 1993 without problems. Lubricity was evaluated with HFRR test and compared to the pump rig results. HFRR overestimated the need for lubricity additives. Fuel sulfur was found to be not the only indicator of lubricity and lubricity of low sulfur diesel was as good as high sulfur when other fuel parameters were kept constant.

Diesel fuel was reformulated by reducing sulfur to < 0.005 wt-%, aromatics to < 20 vol-% and by limiting heavy polyaromatics. This reduced NOx, particulate, PAH and mutagenic emissions plus exhaust odor. Oxidation catalysts operated well. Less deposits formed in the EGR system. Fuel lubricity was enhanced by additives evaluated by injection pump tests and HFRR. Three years of field testing with 140 buses showed no fuel related problems. Oil change period could be lengthened and fuel consumption was unchanged. Demand for reformulated fuel was triggered by differentiating taxation based on quality. Fuels have been used since 1993 without problems. Life cycle analysis showed no increase of CO2.