Progress on the variable-displacement spark-ignition engine

Conference · Fri Oct 01 04:00:00 EDT 1976

OSTI ID:7325079

A variable-displacement, five-cylinder, spark-ignition research engine was designed, fabricated, and is currently under test. This design reduces partial-load fuel consumption 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 4-1/4 inches as displacement varies from 43 to 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. Over 100 hours of running time have been accumulated to date, mostly in the range of loads and speeds encountered in typical driving situations. Engine dynamometer tests have resulted in data on power, fuel consumption, and emissions, and the latest test data are presented. Tests demonstrate that a substantial fuel saving can be achieved by using the variable-displacement concept.

• Research Organization: Sandia Labs., Livermore, CA (USA)
• DOE Contract Number: E(29-1)-789
• OSTI ID: 7325079
• Report Number(s): SAND-76-8512; CONF-761028-1
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101* -- Internal Combustion Engines-- Spark-Ignition
330603 -- Vehicle Design Factors-- Engine System
330701 -- Emission Control-- Nitrogen Oxides
330702 -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
AUTOMOBILES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COMPRESSION
CONTROL SYSTEMS
CYLINDERS
DESIGN
ENERGY CONSUMPTION
ENGINES
EXHAUST GASES
FUEL CONSUMPTION
GASEOUS WASTES
HYDROCARBONS
INTERNAL COMBUSTION ENGINES
MACHINE PARTS
MECHANICAL TRANSMISSIONS
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
POWER
SPARK IGNITION ENGINES
TESTING
VEHICLES
WASTES