This content is not included in your SAE MOBILUS subscription, or you are not logged in.
The Lubricity of Hydrotreated Diesel Fuels
Published June 24, 1996 by Institution of Mechanical Engineers in United Kingdom
Event: International Seminar on Application of Powertrain and Fuel Technologies to Meet Emissions Standards
It is generally agreed that reduced levels of sulphur in automotive gas oil (AGO) lead to lower tailpipe emissions of diesel particulates and sulphur oxides. Therefore, in line with concerns over the environmental impact of road transport, many countries have already, or are planning to reduce the maximum permitted level of sulphur in AGO. In order to reduce the level of sulphur it is necessary to use some form of hydro-processing. Deep hydrogenation - as that required to produce "environmentally adapted" AGO such as Swedish Class I (10 ppm max. sulfur) - is known to lead to a significant reduction in the natural lubricity characteristics of AGO. The purpose of the work described in this paper was to consider the lubricity characteristics of AGO produced by milder hydrotreatment processes - such as those likely to be used in the production of AGO to meet 500 ppm (mg/kg) max. sulphur specifications.
Road trials, pump durability tests and bench test results confirm that some AGOs manufactured to meet lower sulphur specifications can lead to increased were in sensitive types of diesel injection equipment and that - where necessary - additives can be successfully used to improve the lubricity characteristics of low sulphur AGOs. The results of this work illustrate the need for technically sound and commercially viable specifications to define minimum levels of AGO lubricity - both to protect sensitive equipment already in the market and to ensure that new equipment is designed to be robust with respect to operation on AGO of defined minimum lubricity.