A Fully Variable Mechanical Valvetrain with a Simple Moving Pivot

2005-01-0770

04/11/2005

Event
SAE 2005 World Congress & Exhibition
Authors Abstract
Content
A continuously variable lift, duration and phase mechanical lift mechanism is described, as applied to the intake valvetrain of a SOHC, 4-valve per cylinder, four-cylinder production engine. Improvements in fuel economy were sought by reduction of pumping losses and improved charge preparation, and optimization of WOT torque was attempted by variation of intake valve closing angle.
Adjustment of the mechanism is achieved by movement of the pivot shaft for the rocker arms. The relationship between lift, duration and phase is predetermined at the design stage, and is fixed during operation. There is considerable design flexibility to achieve the envelope of lift curves deemed desirable.
The operation of the mechanism is described, as are the development procedure, testing with fixed cams, some cycle simulation, friction testing on a separate rig and dyno testing results for idle, part load and WOT.
Meta TagsDetails
DOI
https://doi.org/10.4271/2005-01-0770
Pages
12
Citation
Riley, M., and Fiddes, D., "A Fully Variable Mechanical Valvetrain with a Simple Moving Pivot," SAE Technical Paper 2005-01-0770, 2005, https://doi.org/10.4271/2005-01-0770.
Additional Details
Publisher
Published
Apr 11, 2005
Product Code
2005-01-0770
Content Type
Technical Paper
Language
English