Particulate Oxidation Catalyst With Dual Pressure-Drop Sensors

• US 20130327019A1
• Filed: 06/08/2012
• Published: 12/12/2013
• Est. Priority Date: 06/08/2012
• Status: Active Grant

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Zhan, Rijing, Weber, Phillip A., Chadwell, Michael A.
• Granted Patent: US 9,046,026 B2
• Time in Patent Office: Days
• US Class Current: 60/274
• CPC Class Codes: F01N 11/002 the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
• CPC Class Codes: F01N 13/0093 the purifying devices are of the same type
• CPC Class Codes: F01N 13/0097 the purifying devices are arranged in a single housing
• CPC Class Codes: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 2900/1406 Exhaust gas pressure
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/106 Auxiliary oxidation catalysts
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method and system for treating exhaust emitted via an exhaust line from a diesel engine. A POC system is installed on the exhaust line, and has at least one diesel oxidation catalyst (DOC), a set of two or more particulate oxidation catalyst (POC) elements, a first differential pressure sensor (ΔP1) to measure the pressure difference across the first and all but the last POC elements, and a second differential pressure sensor (ΔP2) to measure pressure differences across the last POC element. During operation of the engine, ΔP1 is monitored to determine whether its POC elements require active regeneration, and ΔP2 is separately monitored to determine whether its (the last) POC element requires active regeneration.

Claims

1. A method of treating exhaust emitted via an exhaust line from a diesel engine, comprising:

installing at least one diesel oxidation catalyst (DOC) on the exhaust line;

installing a set of one or more particulate oxidation catalysts (POC1 through POCn−

1) in-line downstream of the at least one DOC;

installing a last POC (POCn) downstream of POC1 through POCn−

1;

installing a first differential pressure sensor (Δ

P1) to measure pressure differences across POC1 through POCn−

1;

installing a second differential pressure sensor (Δ

P2) to measure pressure differences across POCn;

during operation of the engine, monitoring Δ

P1 to determine whether POC1 through POCn−

1 require active regeneration; and

during operation of the engine, monitoring Δ

P2 to determine whether POCn requires active regeneration.

2. The method of claim 1, wherein the step of monitoring Δ

P1 is performed by determining whether the pressure drop exceeds a predetermined threshold.

3. The method of claim 1, wherein the step of monitoring Δ

P2 is performed by determining whether the pressure drop across POCn deviates from a near-constant value.

4. The method of claim 1, wherein the control signal differentiates between regeneration of POC1 through POCn−

1 and regeneration of POCn.

5. The method of claim 1, wherein POC1 through POCn−

1 comprise a single POC element.

6. The method of claim 1, wherein POC1 through POCn-1 comprise a more than one POC element.

7. The method of claim 1, further comprising the step of using a temperature sensor to determine whether the temperature at the DOC indicates that passive regeneration of the POCs has occurred.

8. The method of claim 1, wherein the first differential pressure sensor measures the pressure difference across the DOC as well as across POC1 through POCn−

1.

9. A particulate oxidation catalyst (POC) system for treating exhaust emitted via an exhaust line from a diesel engine, comprising:

at least one diesel oxidation catalyst (DOC) on the exhaust line;

installing a set of one or more particulate oxidation catalysts (POC1 through POCn−

1) in-line downstream of the at least one DOC;

a last POC (POCn) downstream of POC1 through POCn−

1;

a first differential pressure sensor (Δ

P1) to measure pressure differences across POC1 through POCn−

1;

a second differential pressure sensor (Δ

P2) to measure pressure differences across POCn;

a control unit programmed to;

during operation of the engine, monitor Δ

P1 to determine whether POC1 through POCn−

1 require active regeneration, to monitor Δ

P2 to determine whether POCn requires active regeneration, to deliver a control signal to initiate active regeneration of POC1 through POCn−

1 if Δ

P1 represents a pressure drop above a predetermined threshold, and to deliver a control signal to initiate active regeneration of POCn if Δ

P2 represents a pressure drop deviation from a constant or near constant value.

10. The system of claim 9, wherein monitoring Δ

P1 is performed by determining whether the pressure drop exceeds a predetermined threshold.

11. The system of claim 9, wherein monitoring Δ

P2 is performed by determining whether the pressure drop across POCn deviates from a near-constant value.

12. The system of claim 9, wherein the control signal differentiates between regeneration of POC1 through POCn−

1 and regeneration of POCn.

13. The system of claim 9, wherein POC1 through POCn−

1 comprise a single POC element.

14. The system of claim 9, wherein POC1 through POCn−

1 comprise a more than one POC element.

15. The system of claim 9, further comprising a housing containing the at least one DOC, POC1 through POCn−

1 and POCn.

16. The system of claim 9, wherein the first differential pressure sensor measures the pressure difference across the DOC as well as across POC1 through POCn−

1.