A test procedure was developed for rating the driveability performance of European cars equipped with manual chokes and manual transmissions so that the effects of ambient temperature and fuel volatility could be assessed. Driveability was rated subjectively, using the CRC rating scale with minor alterations. Cold-start times and warm-up times can also be measured by the procedure. The design of the intake system determines the basic driveability performance of a car. Important factors are inlet air temperature, carburetor and choke characteristics, and inlet manifold shape. Recent demands for better fuel consumption and lower exhaust emissions have led to weaker mixtures and less choke use. It was found that carburetted European vehicles respond to changes in gasoline volatility and ambient temperature. Significant improvements in driveability can be achieved by engine hardware changes which improve mixture preparation (e.g. quick warm-up inlet manifolds, heated intake air systems, and improved automatic choke systems). Vehicles with fuel-injected engines are not affected by ambient conditions or fuel quality.

  • Availability:
  • Supplemental Notes:
    • Presented at SAE Passenger Car Meeting, Troy, Michigan, 5-9 June 1978.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Barker, R F
    • Hirst, S L
    • Caddock, B D
  • Publication Date: 1978

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00396337
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: SAE 780652, HS-025 542U
  • Files: HSL, USDOT
  • Created Date: Aug 31 1985 12:00AM