This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Phased Air/Fuel Ratio Perturbation - A Fuel Control Technique for Improved Catalyst Efficiency
Technical Paper
2000-01-0891
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
This paper describes the results of a study that examined the mechanism of phased perturbation as an emissions control technique. Phased perturbation involves independently controlling the fuel delivered to each bank of a dual bank engine (or each cylinder of a single manifold engine), which allows the two banks to have an adjustable, relative Air/Fuel (A/F) perturbation phase-shift from one another. The phase shifted exhaust is then recombined to achieve a near stoichiometric mixture prior to entering a single underbody catalyst. Phase shifting the exhaust Air/Fuel ratio creates a situation in which both rich exhaust constituents (unburnt hydrocarbons and carbon monoxide) and lean exhaust constituents (oxygen and oxides of nitrogen) arrive at the catalyst at the same time.
The results of the study showed that phased perturbation produced a significant effect on A/F control and catalyst THC, CO, and NOx efficiency. The magnitude of the effect of phase shift on conversion efficiency was comparable to the effect of both frequency and amplitude. Due to the magnitude of the effect of A/F phase shifting on catalyst efficiency, it has been identified as a third dimension of A/F control for optimization of exhaust composition as it enters the catalyst. The development of this technique could augment or replace EGR for NOx control (particularly at high catalyst space velocity conditions and during cold engine operation when EGR may not be desirable), may greatly improve overall CO efficiency, and may help reduce cold-start vehicle emissions.
Recommended Content
Authors
Topic
Citation
Webb, C., DiSilverio, W., Weber, P., Bykowski, B. et al., "Phased Air/Fuel Ratio Perturbation - A Fuel Control Technique for Improved Catalyst Efficiency," SAE Technical Paper 2000-01-0891, 2000, https://doi.org/10.4271/2000-01-0891.Also In
References
- Heck, R. Farrauto, R. Catalytic Air Pollution Control Commercial Technology Engelhard Corporation Research and Development 1995 Van Nostrand Reinhold
- Spindt, R.S. “Air-Fuel Ratios from Exhaust Gas Analysis,” ASE 650507
- Urban, C.M. “Stoichiometry and Oxidation Potential Factors,” SwRI DER Internal publication 1994
- Kaneko, Y. et al “Effect of Air-Fuel Ratio Modulation on Conversion Efficiency of Three-Way Catalysts,” SAE paper 780607
- Falk, C. Mooney, J. “Three-Way Conversion Catalysts: Effect of Closed-Loop Feed-Back Control and Other Parameters on Catalyst Efficiency,” SAE paper 800462
- Heck, R. Patel, K. “Platinum versus Palladium Three-Way Catalysts - Effect of Closed-Loop Feed-back Parameters on Catalyst Efficiency,” SAE 892094
- Schlatter, L. et al “A Laboratory Reactor System for Three-Way Catalyst Evaluation,” General Motors, GMR-2911 87
- Bosch, Automotive Electric/Electronic Systems Robert Bosch, GmbH 1995
- Ribbens, W. B. Understanding Automotive Electronics fifth Butterworth-Heinemann 1998
- Adomaitis, J.R. Heck, R.M. “Vehicle Control Strategies Effect on Catalyst Performance,” SAE 881597
- Muraki, H. et al “Behavior of Automotive Noble Metal Catalysts in Cycled Feedstreams,” I&EC 24 1 43 49
- Webb, C.C. Bykowski, B.B. Weber, P.A. McKinnon, D.L. “Using Advanced Emission Control Systems to Demonstrate LEV II ULEV on Light-Duty Gasoline Vehicles SAE Paper 1999-01-0774 March 1-4 1999