Filters for engine exhaust particulates

• US 6,862,927 B2
• Filed: 05/16/2003
• Issued: 03/08/2005
• Est. Priority Date: 05/16/2003
• Status: Expired due to Fees

• Current Assignee: PENN Automotive Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Craig, Angus G., Sawyer, Constance B., Locker, Robert J.
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US10/439,562
• Publication Number:
  US 20040226352A1
• Time in Patent Office: 662 Days
• Field of Search: 731/181, 73/233.1, 73/233.2, 701/101, 701/102, 701/103, 701/108, 701/109
• US Class Current: 73/114.69
• CPC Class Codes: B01D 2273/18 Testing of filters, filter elements, sealings
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/448 by temperature measuring
• CPC Class Codes: B21K 1/702 Clinch nuts
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 2240/02 a heat exchanger
• CPC Class Codes: F01N 2330/06 Ceramic, e.g. monoliths
• CPC Class Codes: F01N 3/021 by means of filters
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/027 using electric or magnetic heating means
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F16B 37/068 by deforming the material of the support, e.g. the sheet or plate
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The regeneration responses of diesel engine exhaust filters are mapped by conducting multiple regeneration runs under controlled conditions of soot loading, exhaust temperature, exhaust flow rate, exhaust oxygen content and/or other regeneration condition variables to generate a multivariate response surface or filter map that can be used to predict regeneration response under other conditions and aid in the design and active management of the filters to improve filter efficiency and extend filter service life.

Claims

1. A method for determining the regeneration performance of an engine exhaust gas particulate filter under multiple sets of filter regeneration conditions which comprises the steps of:

(a) loading the filter with a measured quantity of combustible particulate material;

(b) conveying through the filter a gas stream characterized by two or more exhaust gas inlet variables selected from the group consisting of inlet oxygen content O₂, inlet temperature T_i, inlet flow rate V_i, and inlet hydrocarbon content HC_i, at least two of the exhaust variables being known;

(c) initiating combustion of the particulate material while maintaining the at least two exhaust inlet variables constant;

(d) determining at least one of a peak combustion temperature and a residual particulate material content for the filter resulting from the combustion; and

(e) repeating steps (a)-(d) at different values for at least one of the two exhaust inlet variables.

2. A method in accordance with claim 1 wherein the combustible particulate material is a synthetic carbon powder and the gas stream is a synthesized nitrogen-air mixture.

3. A method for modeling the regeneration performance of a filter design of known honeycomb geometry and composition type which comprises the steps of:

(a) loading a sample filter of the known honeycomb geometry and composition type with a measured quantity S of combustible particulate material;

(b) conveying through the filter an exhaust gas stream characterized by two or more exhaust inlet variables selected from the group consisting of inlet oxygen content O₂, inlet temperature T_i, inlet flow rate V_i, and inlet hydrocarbon content HC_i, at least two of the exhaust variables being known;

(c) initiating combustion of the combustible particulate material while maintaining the at least two exhaust inlet variables constant;

(d) determining the value of a filter response variable R selected from the group of;

a filter peak combustion temperature and filter regeneration efficiency for the filter resulting from the combustion;

(e) repeating steps (a)-(d) to generate a data set correlating values of the selected filter response variable R with different values of S and each of the at least two inlet variables, and

(f) extending and/or extrapolating the data in the data set to generate a response surface correlating the at least one response variable R with different values of S and the at least two exhaust inlet variables, such that additional values of the response variable R can be calculated from the response surface.

4. A method in accordance with claim 3 wherein the filter response variable R is selected from the group consisting of filter peak combustion temperature and filter regeneration efficiency, and wherein the exhaust gas stream variables are selected from the group consisting of exhaust gas inlet oxygen content O₂, inlet temperature T_i, inlet flow rate V_i, and inlet hydrocarbon content HC_i.

5. A numerical model of the form R=f(V1, V2, . . . , Vn) correlating a filter regeneration response value R for an engine exhaust particulate filter of known material type and geometry with a function f of a set of terms (V1, V2, . . . Vn), wherein R is a filter response value selected from the group of:

peak filter regeneration temperature and filter regeneration efficiency, the set of terms (V1, V2, . . . Vn) includes terms dependent on the values of at least two regeneration condition variables selected from the group consisting of inlet oxygen content O₂, inlet temperature T_i, inlet flow rate V_i, inlet hydrocarbon content HC_i, and initial combustible particulate loading S, and the function f is an empirical function correlating values of R with values of the regeneration condition variables.

6. A numerical model in accordance with claim 5, wherein the function f is a polynomial function of 6-10 terms including first order, second order or interactive terms dependent on the value of the regeneration condition variables.

7. A method for aiding a customer in the design of a diesel exhaust emissions control system, comprising:

(a) selecting a diesel particulate filter of predetermined geometry and composition type based on customer requirements;

(b) generating a numerical model of filter regeneration response characteristics for the selected filter, the numerical model correlating a regeneration response R with a set of terms (V1, V2, . . . Vn) that includes terms dependent on at least two different filter regeneration conditions;

(c) storing the numerical model in digital form on a digital information storage medium; and

(d) providing the numerical model in combination with the selected diesel particulate filter to the customer.

8. A method in accordance with claim 7 wherein the numerical model is of the form R=f(V1, V2, . . . , Vn), wherein R is a filter response value selected from the group of:

peak filter regeneration temperature and filter regeneration efficiency, the set of terms (V1, V2, . . . Vn) includes terms dependent on the values of at least two regeneration condition variables selected from the group consisting of inlet oxygen content O₂, inlet temperature T_i, inlet flow rate V_i, inlet hydrocarbon content HC_i, and initial combustible particulate loading S, and the function f is an empirical function correlating values of R with values of the regeneration condition variables.

9. A method in accordance with claim 8 wherein the numerical model includes indicators of limits on the values of the regeneration condition variables, said limits when observed being effective to limit the correlating filter response value R to a value compatible with a material composition and geometric design for the selected diesel particulate filter.