This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The Effect of Fuel Sulfur on the OBD-II Catalyst Monitor
Annotation ability available
Sector:
Language:
English
Abstract
The effect of fuel sulfur on the dual HEGO sensor OBD-II catalyst monitor has been investigated. Laboratory studies revealed two competing effects of the fuel sulfur on the operation of the catalyst monitor: 1. the loss of catalyst oxygen storage capacity, and 2. the degradation in the response rate of the rear HEGO sensor. The magnitude of the loss in catalyst OSC relative to the increase in rear HEGO sensor response time determined whether the rear HEGO sensor index increased, decreased, or remained constant as the fuel sulfur level was increased. The effect of fuel sulfur on tailpipe emissions and the catalyst monitor was also measured for two LEVs equipped with Pd-only catalyst technology (a 1997MY Escort and a 1998MY Crown Victoria). For both vehicles, the effect of the fuel sulfur on the rear HEGO sensor response characteristics dominated; as the fuel sulfur level was increased, tailpipe emissions increased, but the rear HEGO sensor index decreased. The results of both the laboratory and vehicle studies indicate that there is minimal risk for false catalyst monitor MIL activation due to fuel sulfur with LEV/ULEV catalyst technology. However, the findings of this work also clearly show that the risk for false passes is high and that the increased variability in the catalyst monitor which results due to fuel sulfur will make compliance with the 1.75x emission threshold for LEV/ULEVs technically infeasible.
Recommended Content
Authors
Topic
Citation
Hepburn, J., Sweppy, M., and Zaghati, Z., "The Effect of Fuel Sulfur on the OBD-II Catalyst Monitor," SAE Technical Paper 972855, 1997, https://doi.org/10.4271/972855.Also In
References
- “The Effect of Three-Way Catalyst Formulation on Sulfur Tolerance and Emissions from Gasoline Fueled Vehicles” Beckwith, P. Bennett, P.J. Goodfellow, C.L. Brisley, R.J. Wilkins, A. SAE Paper 940310 1994
- “Effects of Gasoline Sulfur Level on Mass Exhaust Emissions-Auto/Oil Air Quality Improvement Research Program” Benson, J.D. Burns, V. Gorse, R.A. Hochhauser, A.M. Koehl, W.J. Painter, L.J. Reuter, R.M. SAE Paper 912323 1991
- “Effects of Gasoline Properties on Emissions of Current and Future Vehicles- T 50 , T 90 , and Sulfur Effects- Auto Oil Air Quality Improvement Research Program” Rutherford, J.A. Koehl, W.J. Benson, J.D. Burns, V.R. Hochhauser, A.M. Knepper, J.C. Leppard, W.R. Painter, L.J. Rapp, L.A. Rippon, B. Reuter, R.M. SAE Paper 952510 1995
- “IM240 Emission Tests with a 2.2L Corsica TLEV” Beck, D.D. Short, W.A. Angelos, T.E. Dils, R.R. SAE Paper 942001 1994
- “Effects of Fuel Sulfur Level on Emissions from Transitional Low Emission Vehicles” Sztenderowicz, M.L. Brandy, W.J. Most, W.J. Jetter, S. Sprik, T.L. Doherty, H. Eng, K.D. SAE Paper 952561 1995
- “The Impact of Sulfur on Three-Way Catalysts: Storage and Removal” Beck, D.D. Krueger, M.H. Monroe, D.R. SAE Paper 910844 1991
- “Effects of Sulfur on Noble Metal Automotive Catalysts” Gandhi, H.S. Shelef, M. Applied Catalysis 77 175 1991
- “A Review of the Dual EGO Sensor Method for OBD-II Catalyst Efficiency Monitoring” Hepburn, J.S. Dobson, D.A. Hubbard, C.P. Guldberg, S.O. Thanasiu, E. Watkins, W.L. Burns, B.D. Gandhi, H.S. SAE Paper 942057 1994
- “Impact of Fuel Sulfur on OBD-II Catalyst Monitoring Using the Dual Oxygen Sensor Approach” Beck, D.D. Silvis, T.W. Mahan, S.T. SAE Paper 941054 1994
- “Vehicle Testing of the OBD-II Catalyst Monitor on a 2.2L Corsica TLEV” Beck, D.D. Short, W.A. SAE Paper 952424 1995
- “Sulfur Effects on California OBD-II Systems” Browning, L.H. Moyer, C.B. SAE Paper 952422 1995
- “The Pulse Flame Combustor Revisited” Hepburn, J.S. Dobson, D.A. Hubbard, C.P. Otto, K. SAE Paper 962118 1996
- “The Effect of MMT on the OBD-II Catalyst Efficiency Monitor” Hubbard, C.P. Hepburn, J.S. Gandhi, H.S. SAE Paper 932855 1993