Enhanced diagnosis of a multi-banked catalyst exhaust system

• US 20040204817A1
• Filed: 04/08/2003
• Published: 10/14/2004
• Est. Priority Date: 04/08/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Yurgil, James R.
• Granted Patent: US 6,882,928 B2
• Time in Patent Office: Days
• US Class Current: 701/114
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: G01M 15/104 using oxygen or lambda-sensors testing catalytic converters F01N3/18, F01N11/007
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Methods and apparatus are provided for diagnosing emissions in a multi-banked catalyst emissions system for a motor vehicle. A method of diagnosing emissions in a multi-banked emissions system suitably includes obtaining an emissions measurement for each bank in the multi-banked emissions system, converting the emissions measurements to scaled values, adding the scaled values to obtain a total emission value, and triggering an indication if the total emission value exceeds a pre-determined maximum. A system for processing emissions from an engine in a motor vehicle typically includes multiple exhaust banks and a processor. Each of the exhaust banks includes a catalytic converter and at least one oxygen sensor. The processor receives measurements from the oxygen sensors, converts the measurements to scaled values as a percentage of a threshold value, computes a total emission value from the scaled values, and triggers an indication if the total emission value exceeds the threshold value.

Claims

1. A method of diagnosing emissions in a multi-banked emissions system, the method comprising the steps of:

obtaining a plurality of emissions measurements, wherein each of the measurements corresponds to one bank of the multi-banked emissions system;

converting each of the plurality of measurements to a scaled value as a percentage of a threshold value;

adding the scaled values to obtain a total emission value for the multi-banked emissions system; and

triggering an indication if the total emission value exceeds the threshold value.

2. The method of claim 1 wherein the emissions measurements comprise oxygen sensor readings.

3. The method of claim 2 wherein the threshold value is based upon a government-imposed limit.

4. The method of claim 1 wherein the scaling step comprises converting each emissions measurement to a percentage of a government-imposed limit.

5. The method of claim 4 wherein the converting step comprises referencing the emissions measurement in a lookup table.

6. The method of claim 1 wherein the triggering step further comprises providing the indication if any of the scaled values exceed the threshold value.

7. A method of diagnosing emissions in a multi-banked emissions system, the method comprising the steps of:

obtaining an emissions measurement for each bank in the multi-banked emissions system;

converting each of the emissions measurements to a scaled value;

adding the scaled values to obtain a total emission value; and

triggering an indication if the total emission value exceeds a predetermined maximum.

8. The method of claim 7 further comprising the step of triggering an indication if any of the scaled values exceeds the predetermined maximum.

9. The method of claim 7 wherein the emissions measurements comprise oxygen storage capacity measurements.

10. The method of claim 7 wherein the converting step comprises referencing the emissions measurement in a lookup table to obtain the scaled value.

11. A system for processing emissions from an engine in a motor vehicle, the system comprising:

a plurality of exhaust banks, each of the exhaust banks comprising a catalytic converter configured to receive a portion of the exhaust produced by the engine and an oxygen sensor configured to monitor the level of oxygen present in the exhaust bank and to provide a measurement corresponding thereto; and

a processor configured to receive the measurements from the oxygen sensors, to convert the measurements to scaled values as a percentage of a threshold value, to add the scaled values to compute a total emission value for the engine, and to trigger an indication if the total emission value exceeds the threshold value.

12. A system for processing emissions from an engine and for generating a display to an operator, the system comprising:

a first exhaust bank coupled to the engine and having a first catalytic converter and a first oxygen sensor;

a second exhaust bank coupled to the engine and having a second catalytic converter and a second oxygen sensor;

a processor operatively coupled to the first and second oxygen sensors and to the display; and

a digital memory in communication with the processor, the memory having instructions executable by the processor stored therein, wherein the instructions comprise;

a first code module comprising instructions configured to obtain a first measurement from the first oxygen sensor and a second measurement from the second oxygen sensor;

a second code module comprising instructions configured to convert the first and second measurements to first and second scaled values;

a third code module comprising instructions configured to compute a total emission value as a function of the first and second scaled values; and

a fourth code module comprising instructions configured to trigger an indication signal to the display if the total emission value exceeds a threshold.

13. The system of claim 12 wherein the digital memory further comprises a lookup table accessible by the second code module.

14. A system for diagnosing emissions in a multi-banked emissions system, the system comprising:

means for obtaining a plurality of emissions measurements, wherein each of the measurements corresponds to one bank of the multi-banked emissions system;

means for converting each of the plurality of measurements to a scaled value as a percentage of a threshold value;

means for adding the scaled values to obtain a total emission value for the multi-banked emissions system; and

means for triggering an indication if the total emission value exceeds the threshold value.