The Effect of Exhaust Variable Cam Phaser Transients on Equivalence Ratio Control in an SI 4 Stroke Engine 2005-01-0763
It is a well established fact that variable camshaft phasing can be used to reduce engine out emissions during steady state operation. However, a transition in camshaft timing which often accompanies engine speed / load changes, can have a significant dynamic impact on volumetric efficiency. The change in volumetric efficiency can be highly unpredictable, and can last for several engine cycles following the endpoint of cam movement. Since precise control of catalyst feedgas equivalence ratio is crucial to meeting increasingly stringent automotive emission requirements, the steady state benefits of cam phasing can be overshadowed by the loss of A/F control during transient operation if the engine control algorithms are not properly designed and calibrated. This paper investigates the impact of exhaust variable cam phaser transients on equivalence ratio control, and the mechanism by which volumetric efficiency is affected.
Citation: Worm, J., "The Effect of Exhaust Variable Cam Phaser Transients on Equivalence Ratio Control in an SI 4 Stroke Engine," SAE Technical Paper 2005-01-0763, 2005, https://doi.org/10.4271/2005-01-0763. Download Citation
Author(s):
Jeremy Worm
Affiliated:
GM Powertrain
Pages: 10
Event:
SAE 2005 World Congress & Exhibition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
Variable Valve Actuation 2005-SP-1968, SAE 2005 Transactions Journal of Engines-V114-3
Related Topics:
Camshafts
SAE MOBILUS
Subscribers can view annotate, and download all of SAE's content.
Learn More »