# US 2014/0150541 A1 · On-board diagnostics system

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- Number: US 2014/0150541 A1
- Document ID: US20140150541A1
- Status: Published application
- Kind: A1
- Application number: 14/073,982
- Filed: 2013-11-07
- Published: 2014-06-05
- Earliest claimed: 2012-11-07
- Assignees: Johnson Matthey Public Limited Company
- Applicants: Johnson Matthey Public Limited Company
- Inventors: Andrew Francis CHIFFEY
- Web page: https://patentgrep.com/patent/US20140150541A1

## CPC

- F01N 11/002: {the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus}
- F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus
- F01N 2550/02: Catalytic activity of catalytic converters
- F01N 2560/12: Other sensor principles, e.g. using electro conductivity of substrate or radio frequency
- G01N 27/82: for investigating the presence of flaws
- Y02T 10/40: Engine management systems
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An on-board diagnostics system for an exhaust system of an internal combustion engine is disclosed. The system comprises one or more ferromagnetic materials and a means for measuring magnetic field strength. Also disclosed is a method for on-board diagnostics of a catalyst component in the exhaust system. The method comprises measuring the magnetic field strength of a ferromagnetic material located in close proximity to the catalyst component and determining whether the ferromagnetic material has been exposed to a temperature above the Curie temperature of the ferromagnetic material, as measured by a decrease in the measured magnetic field strength.

## Claims

### Claim 1

An on-board diagnostics system for an exhaust system of an internal combustion engine, the system comprising one or more ferromagnetic materials and a means for measuring magnetic field strength.

### Claim 2 (depends on 1)

The on-board diagnostics system of claim 1 wherein the ferromagnetic material is selected from the group consisting of iron, Fe2O3, Co, NiOFe2O3, AlNiCo, and alloys thereof.

### Claim 3 (depends on 1)

The on-board diagnostics system of claim 1 wherein the means for measuring magnetic field strength are selected from the group consisting of magnetometers, Hall-Effect semi-conductor sensors, and Gradiometers.

### Claim 4 (depends on 1)

The on-board diagnostic system of claim 1 wherein the ferromagnetic material is located in close proximity to a catalyst component in the exhaust system.

### Claim 5 (depends on 4)

The on-board diagnostic system of claim 4 wherein the ferromagnetic material is located within a catalyst coating of the catalyst component.

### Claim 6 (depends on 4)

The on-board diagnostic system of claim 4 wherein the ferromagnetic material is located on a separate probe located within a channel of the catalyst component or on a separate probe in close proximity of the catalyst component.

### Claim 7 (depends on 6)

The on-board diagnostic system of claim 6 wherein the separate probe in close proximity of the catalyst component is downstream of the catalyst component.

### Claim 8 (depends on 4)

The on-board diagnostics system of claim 4 wherein the catalyst component comprises a three-way catalyst, a diesel oxidation catalyst, a lean NOx trap, a selective catalytic reduction (SCR) catalyst, a catalyzed soot filter, or an SCR coated filter.

### Claim 9

A method for on-board diagnostics of a catalyst component in an exhaust system for an internal combustion engine, the method comprising:
(a) measuring the magnetic field strength of a ferromagnetic material that is located in close proximity to the catalyst component, wherein the ferromagnetic material has a Curie temperature above which the ferromagnetic material loses its ferromagnetic properties; and
(b) determining whether the ferromagnetic material has been exposed to a temperature above the Curie temperature of the ferromagnetic material, as measured by a decrease in the measured magnetic field strength.

### Claim 10 (depends on 9)

The method of claim 9 wherein the ferromagnetic material is located within a catalyst coating of the catalyst component.

### Claim 11 (depends on 9)

The method of claim 9 wherein the ferromagnetic material is located on a separate probe located within a channel of the catalyst component or on a separate probe in close proximity of the catalyst component.

### Claim 12 (depends on 11)

The method of claim 11 wherein the separate probe in close proximity of the catalyst component is downstream of the catalyst component.

### Claim 13 (depends on 9)

The method of claim 9 further comprising triggering a malfunction indicator light when the magnetic field strength decreases below a pre-determined value.