SOME EFFECTS OF FUEL BEHAVIOR IN THE ENGINE INTAKE SYSTEM ON EXHAUST EMISSIONS AND VEHICLE DRIVEABILITY

Mixture formation in the intake manifold, affecting exhaust emissions, vehicle driveability and fuel economy, has become of major interest to engine engineers lately. Insufficient evaporation of fuel in the intake manifold is often observed during the engine warming-up period and even after the warming-up period for engines with a coolant-heated type intake manifold. The evaporation ratio was measured and the effects of manifold vacuum, air fuel ratio and mixture temperature on this ratio are shown. The amount of liquid fuel in the intake manifold was estimated from the results of our experiment and from other data found in published reports. Analytical investigation shows that the amount of liquid fuel as well as the evaporation ratio plays an important role in transitional operations such as acceleration and deceleration. It has been proved that accumulation of liquid fuel in the intake manifold makes the mixture extremely lean just after the throttle valve is opened thereby causing poor driveability while accelerating. It has also been shown that evaporation of liquid fuel in the intake manifold makes the mixture extremely rich just after the throttle valve is closed thereby increasing CO emission while decelerating. An auxiliary acceleration pump and an air supply valve have been introduced to prevent abnormal air fuel ratio changes during the transitional operations. The effects of those new devices are also described. /Author/TRRL/

  • Supplemental Notes:
    • This report was presented at the 16th International Automobile Technical Congress.
  • Corporate Authors:

    International Federation of Auto Techniques Engs

    3 Avenue du President Wilson
    F 75116 Paris,   France 
  • Authors:
    • Nakada, M
    • Kajiya, S
    • AMANO, M
  • Publication Date: 0

Media Info

  • Pagination: 1 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00163387
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: May 3 1978 12:00AM