EMISSIONS AND FUEL ECONOMY OF A CADILLAC PROTOTYPE WITH MODULATED DISPLACEMENT ENGINE

The deactivation of one or more engine cylinders is a method that has been proposed as offering potential for vehicle fuel economy improvements. At low power output, the throttle is nearly closed. This introduces a throttling loss, which is the energy that the engine must expend to draw the fuel/air mixture through the carburetor throttle opening. By operating an engine on a reduced number of cylinders and operating these cylinders at higher power levels, the throttling losses are appreciably reduced. The operating cylinders are therefore run at a high brake-mean-effective pressure (BMEP) and therefore potentially more efficiently. A cylinder deactivation system is being considered for use in several 1981 Cadillac models. Other cylinder deactivation systems are currently under development in the United States. Because EPA had not recently tested a cylinder deactivation system designed for current vehicles, EPA contacted the Cadillac Motor Division of GM and requested the loan of a vehicle with a cylinder deactivation system installed. Cadillac made available a system installed in a prototype vehicle.

• Corporate Authors:

  Environmental Protection Agency

  Test and Evaluation Branch, 2565 Plymouth Road
  Ann Arbor, MI  United States  48105
• Authors:
  • BARTH, E A
• Publication Date: 1980-4

Media Info

• Pagination: 15 p.

Subject/Index Terms

• TRT Terms: Air pollution; Automobiles; Carburetors; Exhaust gases; Fuel consumption; Fuel systems; Throttles; Vehicle power plants
• Uncontrolled Terms: Cylinders
• Old TRIS Terms: Automobile engines; Deactivation; Throttling
• Subject Areas: Energy; Highways; Vehicles and Equipment; I96: Vehicle Operating Costs;

Filing Info

• Accession Number: 00327096
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: EPA-AA-80-14 Tech Rpt.
• Files: TRIS
• Created Date: Feb 18 1981 12:00AM