This article first discusses various ways of attempting to reduce fuel consumption in diesel and petrol engines, then describes the remarkable Mitsubishi lean-burn engine for cars, which revives the old idea of direct injection (DI) for petrol engines. DI depends on: (1) high injection pressure, to turn oil into a fine spray; and (2) extensive turbulence in the upper cylinder, to help break up the fuel and mix it with the air. There has been a convincing case for lean-burn combustion, but, until recently, the three-way catalytic converter has ruled unchallenged. The Mitsubishi engine is a 1.8l four-cylinder unit with a double overhead camshaft. Instead of entering the combustion chamber from one side, its inlet tracts run downwards into one side of the chamber's roof. The electronically controlled injector is fired at part load later in the compression cycle, or at full throttle much earlier, during the intake stroke. The engine's claimed advantages include: (1) ability to burn lean normally, but provide 'fat' power when it is required; (2) up to 25% fuel savings; (3) about 7% better mpg; (4) up to 85% more peak power; (5) 12% more peak torque; (6) 10dB less noise emission; (7) no particulate emission; (8) 8% less weight; (9) 50% better power-to-weight ratio; and (10) 40% lower manufacturing cost.

  • Availability:
  • Corporate Authors:

    Institute of Road Transport Engineeers

    1 Cromwell Place
    London SW1 25F,   England 
  • Authors:
  • Publication Date: 1996-1


  • English

Media Info

  • Pagination: p. 22-3
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00722439
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jun 28 1996 12:00AM