CONTROLLING ENGINE LOAD BY MEANS OF LATE INTAKE-VALVE CLOSING
Varying the timing of intake-valve closing was examined on a single-cylinder engine as a means for controlling the load of a homogeneous-charge spark-ignition engine. The engine was operated unthrottled, with load control obtained by holding the intake valve open during a portion of the compression stroke. This allowed the piston to push part of the cylinder charge back into the intake manifold. Comparisons to a conventional engine showed the late intake-valve-closing engine to have (1) lower pumping losses, (2) lower specific fuel consumption, (3) lower nitric oxide emissions, and (4) similar HC emissions. However, the fuel-economy benefit offered by this load-control concept would be reduced by the frictional losses of a control mechanism. The current trend toward lower vehicular power/weight ratios also would diminish the impetus for this approach.
- From SAE Meeting held June 9-13, 1980.
Warrendale, PA USA 15096
- Tuttle, J H
- Publication Date: 1980
- Features: References;
- Pagination: 15 p.
- Society of Automotive Engineers Preprint
- Publisher: Society of Automotive Engineers
- TRT Terms: Control; Exhaust gases; Fuel conservation; Fuel injection; Intake valves; Internal combustion engines; Spark ignition engines; Valves; Vehicle power plants
- Old TRIS Terms: Automobile engines; Closing; Intake systems
- Subject Areas: Energy; Highways; Vehicles and Equipment; I91: Vehicle Design and Safety;
- Accession Number: 00331763
- Record Type: Publication
- Source Agency: Engineering Index
- Report/Paper Numbers: SAE 800794
- Files: TRIS
- Created Date: Jul 9 1981 12:00AM