Catalytic converter decontamination method

Details Catalytic converter decontamination method Catalytic converter decontamination method

2001-10-30

2003-04-01

Denion, Thomas (Department: 3748)

Power plants

Internal combustion engine with treatment or handling of...

Methods

C060S276000, C060S277000, C060S285000, C060S286000, C060S295000

Reissue Patent

active

RE038051

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a sulfur decontamination method for a three way exhaust catalytic converter of an internal combustion engine.
BACKGROUND OF THE INVENTION
To meet current emission regulations, automotive vehicles must have on-board diagnostic systems to detect the malfunction of any component of the emission system, including a catalytic converter. At the same time, the exhaust system must purify the exhaust gas to reduce the concentration of certain regulated compounds. To meet the increasingly low level of exhaust emissions required, new catalytic converter formulations have been found that are more effective at accomplishing this goal. However, one drawback is that the new catalytic converter formulations are increasingly susceptible to sulfur contamination. While sulfur content in fuel is limited to 80 ppm in some states, fuel in other states can contain as much as 1000 ppm of sulfur.
Catalytic converter monitoring systems are known in which an upstream and a downstream exhaust gas oxygen sensor are compared to give an indication of catalytic degradation. If sulfur contamination occurs, these systems will diagnose the contamination and illuminate a malfunction indicator. As a result, a new catalytic converter will be required. An example of such an approach is disclosed in U.S. Pat. No. 5,357,751.
The inventors herein have recognized numerous problems with the above approaches. For example, because sulfur contamination may not be permanent, a sulfur contaminated catalytic converter would be replaced and discarded when it may be possible to decontaminate the catalytic converter and restore the exhaust purifying capability.
SUMMARY OF THE INVENTION
An object of the invention claimed herein is to provide a method to restore the exhaust purifying capability of a sulfur contaminated catalytic converter.
The above object is achieved, and problems of prior approaches overcome, by a catalytic converter decontamination method for an internal combustion engine. The method comprises the steps of: generating a catalytic converter contamination signal when catalytic converter efficiency falls below a desired level; elevating the catalytic converter temperature in response to said catalytic converter contamination signal; operating the engine in a rich condition for a first predetermined interval after said temperature elevation; and operating the engine in a lean condition for a second predetermined interval following said first predetermined interval.
By attempting to decontaminate the catalytic converter in response to degraded performance, it is possible to restore the operation of the catalytic converter if sulfur contamination was the problem. Thus, the contamination and poor performance of the catalytic converter can be remedied.
An advantage of the above aspect of the invention is that operating the engine at an elevated temperature and in a rich condition can remove sulfur contamination on the catalytic converter and increase catalytic converter performance.
Another advantage of the above aspect of the invention is that operating the engine at an elevated temperature and in a lean condition after operating at an elevated temperature and in a rich condition can further remove sulfur contamination on the catalytic converter and further increase catalytic converter performance.
Yet another advantage of the above aspect of the invention is if sulfur contamination was the cause of catalytic converter degradation, both the cost and inconvenience of a replacement system may be avoided.
Other objects, features and advantages of the present invention will be readily appreciated by the reader of this specification.


REFERENCES:
patent: 5357751 (1994-10-01), Orezl
patent: 5402641 (1995-04-01), Katoh et al.
patent: 5537816 (1996-07-01), Ridgway et al.
patent: 5544481 (1996-08-01), Davey et al.
patent: 5601698 (1997-02-01), Innes
patent: 5655363 (1997-08-01), Ito et al.
patent: 5657625 (1997-08-01), Koga et al.
patent: 5724808 (1998-03-01), Ito et al.
patent: 198 27 195 (1999-12-01), None
patent: 198 35 565 (2000-02-01), None
patent: 198 49 082 (2000-02-01), None
patent: 198 50 762 (2000-02-01), None
patent: 199 21 972 (2000-11-01), None
patent: 199 21 973 (2000-11-01), None
patent: 199 21 976 (2000-11-01), None
patent: 199 23 481 (2000-11-01), None
patent: 199 26 146 (2000-12-01), None
patent: 199 35 341 (2001-01-01), None
patent: WO 00/08310 (2000-02-01), None
patent: WO 00/70201 (2000-11-01), None
patent: WO 00/70203 (2000-11-01), None
patent: WO 00/71877 (2000-11-01), None
patent: WO 00/77372 (2000-12-01), None
patent: WO 01/06106 (2001-01-01), None
patent: WO 01/09491 (2001-02-01), None
Emission Control, “Cleaning the Exhaust Gas of Volkswagen FSI Engines,” by Karl-Heinz Glück et al., pp. 19-22 (English and German).
Fuel-stratified Injection from VW, “Fuel-stratified injection from VW,” Jan. 2001, pp. 64-65.
http://www.findarticles.com/cf_0/m0BUX/10_31/65017581/print.jhtml.
http://www.superflow.com/suppport/support-engdyno-lambda.htm.

Affiliated with

Also associated with

Rating

Catalytic converter decontamination method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Catalytic converter decontamination method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalytic converter decontamination method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3034475