At the beginning of 1989, there were about 750,000 natural gas propelled motor vehicles in the world. The majority were passenger cars in commercial urban traffic. After the engine has been converted, the vehicle is equipped with pressure tanks which are heavy and generally limit the action radius to about 400 km. Thus, in addition to environmental reasons, urban traffic is the most obvious area of application for natural gas propelled motor vehicles. The potential of natural gas as an environmentally compatible fuel for piston engines is primarily connected with its particle-free combustion. The simple structure of the methanol molecule in addition means that the hydrocarbons leaving the engine with the exhaust gases are simple in structure. Thus, there is reason to assume that the emissions of complex compounds from natural gas propelled engines are very small. Otto engines are currently considered as having a larger potential for limiting emissions than diesel engines. This means that it is suitable to convert diesel engines to Otto engines if the objective is to cause the lowest possible exhaust gas emissions. Such a conversion results in higher fuel consumption, which partly affects operating costs, and partly can yield higher carbon dioxide emissions. Thanks to the low carbon/hydrogen ratio of natural gas, fuel consumption can increase by about 30% before creating an increase of carbon dioxide emissions from a given mototr vehicle. Trials with diesel engines converted to Otto engines have shown an increase of fuel consumption by 20-50%. The increase of fuel consumption is reduced at higher loads. There are presently two ways to minimize the exhaust emissions from natural gas propelled Otto engines. One is the use of a three-way catalytic converter. The other alternative is the so-called lean burn technique.

  • Corporate Authors:

    Swedish Board for Technical Development

    P.O. Box 43200
    S-100 72 Stockholm,   Sweden 
  • Publication Date: 1989


  • Swedish

Media Info

  • Pagination: 309 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00496251
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: STU-I-751
  • Files: TRIS
  • Created Date: Aug 31 1990 12:00AM