A variable-displacement, five-cylinder, spark-ignition research engine has been designed, fabricated, and tested. This design reduces partial-load fuel concumption by reducing throttling and friction losses. Power is controlled by changing the piston stroke rather than by throttling, except at idle and very low power levels. A linkage arrangement allows for continuous changes in stroke and therefore in engine displacement. The prototype has a bore of 3.375 inches, and stroke varies from 1 to 4 exp 1/sub 4 inches as displacement varies from 43 tp 190 cubic inches. The linkage concept is such that clearance volume can be changed in proportion to the stroke. Thus nearly constant compression ratio can be achieved, or (by proper selection of the linkage dimensions) compression ratio can be tailored to optimize the design. During design, dynamic analyses of various configurations of the engine were done to determine member loads and unbalanced forces and to assist in selecting the linkage configuration. Dynamic analysis was also used to select five as the number of cylinders, to determine the firing order to reduce engine vibration, and to compare vibration with that of a conventional engine. An engineering model of the engine fluid dynamics was also developed and was used to predict engine performance, to select cam contours, and to optimize cam contours, and to optimize cam timing. (ERA citation 03:010664)

  • Supplemental Notes:
    • ERDA Constructors' Coordination Meeting, Detroit, Michigan, October 4, 1977.
  • Corporate Authors:

    Sandia Laboratories

    P.O. Box 5800
    Albuquerque, NM  United States  87115

    Energy Research and Development Administration

    20 Massachusetts Avenue, NW
    Washington, DC  United States  20590
  • Authors:
    • Robinson, C W
  • Publication Date: 1977-9

Media Info

  • Pagination: 21 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00175414
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: CONF-771037-1
  • Contract Numbers: EY-76-C-04-0789
  • Files: TRIS
  • Created Date: Sep 14 1978 12:00AM