COMPRESSION RATIO EFFECTS WITH LEAN MIXTURES

To investigate the fuel-economy benefits of increased compression ratio in modern emission-controlled engines, the compression ratios of two car makes were increased one unit while holding emission levels and performance nearly constant. All cars were modified for lean-burn operation by using the Turbulent Flow Manifold, a carburetor adjusted for lean air-fuel mixtures, and special calibration of ignition timing and exhaust gas recycle rate. Exhaust port liners and a decleration valve were used to control the tendency for HC emissions to increase at higher compression ratios. In addition, thermal reactors were installed on one high-compression car. The increased efficiency of this aftertreatment device allowed a simultaneous improvement in fuel economy and decrease in hydrocarbon emissions. Based on fuel economy gains and refining savings, this car offers an 8.2% fuel savings over its 1977 certification counterpart. /SASI/

  • Corporate Authors:

    Society of Automotive Engineers

    400 Commonwealth Drive
    Warrendale, PA  USA  15096
  • Authors:
    • Marsee, F J
    • Olree, R M
    • Adams, W E
  • Publication Date: 1977-6

Media Info

  • Pagination: 24 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00173200
  • Record Type: Publication
  • Report/Paper Numbers: SAE 770640
  • Files: TRIS
  • Created Date: May 3 1978 12:00AM