Catalytic converter function detection

• US 20030037538A1
• Filed: 08/16/2001
• Published: 02/27/2003
• Est. Priority Date: 08/16/2001
• Status: Active Grant

• Current Assignee: SPX Corporation
• Original Assignee: SPX Corporation
• Inventors: Rendahl, Craig S., Foley, Theresa A.
• Granted Patent: US 6,857,262 B2
• Time in Patent Office: Days
• US Class Current: 60/276
• 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: F01N 2550/02 Catalytic activity of catalytic converters
• CPC Class Codes: F02D 2041/1468 the characteristics being an ammonia content or concentration of the exhaust gases
• CPC Class Codes: F02D 2041/1472 the characteristics being a humidity or water content of the exhaust gases
• CPC Class Codes: F02D 41/1444 characterised by the characteristics of the combustion gases
• CPC Class Codes: F02D 41/1452 the characteristics being a COx content or concentration
• CPC Class Codes: F02D 41/1459 the characteristics being a hydrocarbon content or concentration
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method and system detects the function of a catalytic converter in a vehicle using data received from an open path emissions sensor. The factors considered include whether the vehicle moving on a road is operating in a closed loop operating condition, whether the vehicle is operating in a cold start mode, and the hydrocarbon and other tailpipe emissions concentrations in an exhaust stream of the vehicle as measured by the open path sensor.

Claims

1. A method of detecting the function of a catalytic converter in a vehicle, comprising:

determining a first indication corresponding to whether a vehicle moving on a road is operating in a closed loop operating condition;

determining a second indication corresponding to whether the vehicle is operating at a temperature that is substantially at least equal to its normal operating temperature;

receiving data collected by an emissions sensor, wherein the data corresponds to a plurality of measured hydrocarbon and other tailpipe emissions concentrations in an exhaust stream of the vehicle; and

determining a third indication corresponding to whether the data is indicative of a properly functioning catalytic converter.

2. The method of claim 1 wherein the step of determining a first indication comprises:

measuring a speed of the vehicle;

measuring an acceleration of the vehicle;

measuring a slope of the road;

measuring a mass of the vehicle;

measuring at least one ambient condition;

calculating, using the speed, the acceleration, the slope, the mass, and the at least one ambient condition, a specific power; and

comparing the specific power to a predetermined limit.

3. The method of claim 2 wherein the step of determining a first indication further comprises adjusting the acceleration to correspond to the slope.

4. The method of claim 1 wherein the step of determining a second indication comprises:

measuring, using the emissions sensor, an amount of water vapor in the exhaust stream;

measuring, using the emissions sensor, an amount of carbon dioxide in the exhaust stream;

determining, using the amount of water and the amount of carbon dioxide, a ratio of water and carbon dioxide; and

comparing the ratio to a predetermined fuel factor.

5. The method of claim 1 wherein the step of determining a second indication comprises:

measuring, using the emissions sensor, an amount of 1,3-butadiene in the exhaust stream; and

determining whether the amount exceeds a predetermined threshold.

6. The method of claim 1 wherein the step of determining a third indication comprises:

measuring, using the emissions sensor, an amount of ethylene in the exhaust stream;

measuring, using the emissions sensor, an amount of acetylene in the exhaust stream;

calculating a ratio of the amount of ethylene and the amount of acetylene; and

comparing the ratio to a predetermined threshold.

7. The method of claim 1 wherein the step of determining a third indication comprises:

measuring, using the emissions sensor, an amount of total hydrocarbons in the exhaust stream;

measuring, using the emissions sensor, an amount of methane in the exhaust stream;

calculating a ratio of the amount of total hydrocarbons and the total methane; and

comparing the ratio to a predetermined threshold.

8. The method of claim 1 wherein the step of determining a third indication comprises:

measuring, using the emissions sensor, an amount of ammonia in the exhaust stream; and

comparing the amount of ammonia to a predetermined threshold.

9. The method of claim 1 wherein the step of determining a third indication comprises:

measuring, using the emissions sensor, an amount of benzene in the exhaust stream;

measuring, using the emissions sensor, an amount of toluene in the exhaust stream;

calculating a ratio of the amount of benzene and the amount of toluene; and

comparing the ratio to a predetermined threshold.

10. The method of claim 9 wherein the steps of calculating and comparing are not required if the first indication is indicative of an open loop operating condition.

11. A system for determining whether a moving vehicle has a properly functioning catalytic converter, comprising:

an emissions sensor capable of measuring a plurality of measured hydrocarbons in an exhaust stream of a moving vehicle;

a processor in communication with the emissions sensor; and

a memory in communication with the processor;

wherein the memory contains computer program instructions that instruct the processor to perform the steps of;

determining a first indication corresponding to whether the vehicle is operating in a closed loop operating condition;

determining whether the vehicle is operating at a temperature that is substantially at least equal to its normal operating temperature;

receiving data collected by the emissions sensor, wherein the data corresponds to a plurality of measured hydrocarbon concentrations in an exhaust stream of the vehicle; and

determining whether the data is indicative of a properly functioning catalytic converter.

12. The system of claim 11 wherein the memory contains computer program instructions that further instruct the processor to perform the steps of:

measuring a speed of the vehicle;

measuring an acceleration of the vehicle;

measuring a slope of a road;

measuring a mass of the vehicle;

measuring at least one ambient condition;

calculating, using the speed, the acceleration, the slope, the mass, and the at least one ambient condition, a specific power; and

comparing the specific power to a predetermined limit.

13. A catalytic converter function detection system, comprising:

a means for determining a first indication corresponding to whether a vehicle moving on a road is operating in a closed loop operating condition;

a means for determining a second indication corresponding to whether the vehicle is operating at a temperature that is substantially at least equal to its normal operating temperature;

a means for receiving data collected by an open path emissions sensor, wherein the data corresponds to a plurality of measured hydrocarbon and other tailpipe emissions concentrations in an exhaust stream of the vehicle; and

a means for determining a third indication corresponding to whether the data is indicative of a properly functioning catalytic converter.

14. The system of claim 13 wherein the means for determining a first indication comprises:

a means for measuring a speed of the vehicle;

a means for measuring an acceleration of the vehicle;

a means for measuring a slope of the road;

a means for measuring a mass of the vehicle;

a means for measuring at least one ambient condition;

a means for calculating, using the speed, the acceleration, the slope, the mass, and the at least one ambient condition, a specific power; and

a means for comparing the specific power to a predetermined limit.

15. The system of claim 13 wherein the means for determining a second indication comprises:

a means for measuring an amount of water vapor in the exhaust stream;

a means for measuring an amount of carbon dioxide in the exhaust stream;

a means for determining, using the amount of water and the amount of carbon dioxide, a ratio of water and carbon dioxide; and

a means for comparing the ratio to a predetermined fuel factor.

16. The system of claim 13 wherein the means for determining a second indication comprises:

a means for measuring an amount of 1,3-butadiene in the exhaust stream; and

a means for determining whether the amount exceeds a predetermined threshold.

17. The system of claim 13 wherein the means for determining a third indication comprises:

a means for measuring an amount of ethylene in the exhaust stream;

a means for measuring an amount of acetylene in the exhaust stream;

a means for calculating a ratio of the amount of ethylene and the amount of acetylene; and

a means for comparing the ratio to a predetermined threshold.

18. The system of claim 13 wherein the means for determining a third indication comprises:

a means for measuring and amount of total hydrocarbons in the exhaust stream;

a means for measuring an amount of methane in the exhaust stream;

a means for calculating a ratio of the amount of total hydrocarbons and the total methane; and

a means for comparing the ratio to a predetermined threshold.

19. The system of claim 13 wherein the means for determining a third indication comprises:

a means for measuring an amount of ammonia in the exhaust stream; and

a means for comparing the amount of ammonia to a predetermined threshold.

20. The system of claim 13 wherein the means for determining a third indication comprises:

a means for measuring an amount of benzene in the exhaust stream;

a means for measuring an amount of toluene in the exhaust stream;

a means for calculating a ratio of the amount of benzene and the amount of toluene; and

a means for comparing the ratio to a predetermined threshold.