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 (SAE)

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

Media Info

• Pagination: 24 p.

Subject/Index Terms

• TRT Terms: Compression; Deceleration; Energy; Fuel consumption; Fuels; Hydrocarbons; Ignition; Lean fuel mixtures; Machine valves; Performance; Pollutants
• Old TRIS Terms: Compression ratio; Emission rates; Lean fuel engine
• Subject Areas: Energy; Highways; Safety and Human Factors;

Filing Info

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