This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The Practical Application and Effects of a Variable Event Valve Timing System
Annotation ability available
Sector:
Language:
English
Abstract
In order for automotive engine performance to meet the requirements of maximum power called for by the OEM sales department together with the increasingly punitive legislative demands of reduction in exhaust emissions and fuel consumption, it will be necessary to incorporate a number of additional performance enhancement devices in the engine designs of the near future.
Significant amongst these devices are Variable Valve Timing (VVT) mechanisms, which fall generally into three categories: Variable Phase Systems (VP), Variable Event Timing Systems (VET), Variable Lift and Timing Systems (VLT).
The competent application of a VVT system will result in: Reductions in low speed/load exhaust emissions, Reductions in idle speed, Reductions in low speed/load fuel consumption, Increases in low speed torque, Conservation of high WOT specific power output. This paper describes the engine design refinements required to fit a VET System into a number of cylinder heads, with direct acting cam followers and finger followers and discusses the improvements in fuel consumption, emissions and torque obtained by applying VET to a twin cam gasoline engine.
Recommended Content
Authors
Citation
Lancefield, T., Gayler, R., and Chattopadhay, A., "The Practical Application and Effects of a Variable Event Valve Timing System," SAE Technical Paper 930825, 1993, https://doi.org/10.4271/930825.Also In
References
- Asmus T. W. Perspectives on applications of variable valve timing SAE Paper No. 910445 1991
- Demmelbauer-Ebner W. Dachs A. Lenz H. P. Variable Valve actuation systems for the optimisation of engine torque SAE Paper No 910447 1991
- Continuous Camlobe Phasing Nelson M. T. Elrod A. C. SAE Automotive Engineering Jun 87 81 87
- Stone R. Kwan E. Variable valve actuation mechanisms and the potential for their application SAE Paper No. 890673 1989
- Hara S. Kumagai K. Matsumoto Y. Application of a valve lift and timing control system to an Automotive engine SAE Paper No. 890681 1989
- Griffiths P. Mistry K. M. Variable valve timing for fuel economy improvement - The Mitchell System SAE Paper No. 880392 1988
- Cherry R. A. Farrenkopf M. Trends and developments in Synchronous Belt Camshaft Drives I. Mech E. Conference on Camshaft Drives London September 1991
- Timing Drive systems, Timing Belt versus Chain comparison I. Mech E. Conference on Camshaft Drives London September 1991