August 19, 2002

JAMA Promotes Eco-Friendly Low-Sulfur Diesel Fuel and Regular Inspection of the Vehicles That Use It

With the introduction of environment-friendly low-sulfur diesel fuel, whose sulfur content does not exceed 50ppm [1], the Japan Automobile Manufacturers Association, headed by JAMA Chairman Yoshihide Munekuni, is seizing the opportunity to promote a better understanding of the significance of this new development. The specific goals are twofold: to promote the use of low-sulfur diesel fuel in vehicles equipped with post-treatment devices so as to reduce particulate matter (PM) and other harmful exhaust emissions, and to encourage daily checks and regular inspections for vehicles using the new fuel on a long-term basis. Increased awareness will be promoted through the dissemination of pamphlets, the publication of articles in industry journals, the posting of information on Web sites, and the distribution of explanatory materials to related industry players, among other strategies.

Low-sulfur diesel fuel lowers the sulfur content of diesel fuel to 50ppm (parts per million) or less, in order to reduce PM and other pollutants in vehicle exhaust emissions. This fuel can be used in combination with diesel particulate filters, or DPFs [2], catalytic converters [3], and other sophisticated post-treatment devices to make a significant contribution to environmental protection. Supply of this low-sulfur diesel fuel will begin in September 2002 at many of the service stations handling diesel fuel in the Tokyo metropolitan area (144 locations in all), with plans calling for a gradual shift to the use of low-sulfur diesel fuel on a nationwide scale.

  1. Major Focus of Public Information Activities
    • The use of low-sulfur diesel fuel in vehicles equipped with post-treatment systems:
      With low-sulfur diesel fuel to be made available at a number of service stations in Tokyo, automakers will begin shipments of particulate reduction devices for mounting on the trucks and buses that will be using the fuel. Furthermore, similar devices are to be supplied by non-automaker businesses designated by the Tokyo Metropolitan government (parties concerned will need to consult with the automakers to confirm which vehicle models can be mounted with these devices).
      Automakers are also slating shipments of vehicles already equipped with DPFs and other, even more advanced particulate reduction devices in anticipation of Japan’s enforcement of new emission regulations beginning in October 2003.
      So-called S50 labels will be affixed to vehicles using the new fuel so as to avoid their mistaken refueling with conventional diesel fuel. Vehicle users are expected to always request refueling with the appropriate fuel.
    • Daily checks and regular inspections for vehicles using low-sulfur diesel fuel on a long-term basis:
      Low-sulfur diesel fuel was introduced in Metropolitan Tokyo and other districts in 2001. During an initial trial period, some older route buses operating at high running temperatures [4] experienced some fuel leakage from their fuel injection pumps. This problem did not occur in trucks, passenger cars, or long-distance buses.
      In vehicles operating over extended periods of time under demanding conditions, the rubber sealants (also called O-rings) generally used in fuel injection pumps deteriorate from the heat, causing a decline in sealing performance. Until now, this problem was addressed only when it became urgent to do so.
      With low-sulfur diesel fuel, although fuel leakage is more likely to occur with deteriorated sealants, aromatic content in the fuel declines proportionately, meaning that sealants are correspondingly less likely to deteriorate [5]. Diesel fuel has extremely low flammability and will not self-ignite. However, in the rare event that fuel leakage is confirmed through regular inspections or daily checks, the nearest auto dealer or other informed source or service should be consulted immediately.
      The awareness and cooperation of vehicle users is a vital factor in environmental protection efforts. This refers primarily to users carrying out daily checks, regular inspections and other necessary measures in order to have their vehicles properly diagnosed and maintained in peak condition.
  2. Implementation of Information Activities

    The public information activities described above will be launched beginning in late August 2002.

  3. Channels for Information Dissemination
    • Pamphlets (150,000 copies) will be distributed to service stations handling low-sulfur diesel fuel (144 in total initially) for public dissemination.
    • Related industry journals will feature informative articles for the bus, truck, and auto maintenance industries.
    • The Web sites of JAMA and its individual member companies will post data pertinent to the introduction and use of low-sulfur diesel fuel.
    • Explanatory materials will be distributed to relevant industry players, e.g. bus company operators.
    • Other media and information channels may also be used.


  1. Low-sulfur diesel fuel is diesel fuel from which the sulfur content has been largely removed at the crude-oil refining stage, through the use of desulfurization technologies. Sulfur content has been gradually reduced from past levels of as high as 0.2%, or 500ppm, to the latest standard of 50ppm or less (PPM=parts per million, 50ppm=0.005%).
  2. A diesel particulate filter (DPF) is a device for treating auto exhaust pollutants in which soot and other particulates contained in diesel emissions are eliminated through a filtering and burning process, using filters made of porous ceramic or other materials.
  3. A catalytic converter is a device for treating auto exhaust pollutants in which precious metals and other materials are coated onto the catalytic converter's ceramic surface, and the HC, CO, NOx and other harmful exhaust gases that contact that surface are either oxidized or converted into CO2 or H2O.
  4. High running temperatures in route buses result from the fact that route buses are difficult to cool down because their engines are mounted in the rear part of the vehicle body and the buses themselves operate at low speeds. The frequent number of stops and starts these buses makes also contributes to high temperatures in the vicinity of the engine.
  5. The aromatic content of diesel fuel decreases along with the decrease in sulfur content. Among the many different components of diesel fuel, the aromatic compounds tend to cause the rubber sealants to swell in proportion to the amount of those compounds present in the fuel.