EP0478133A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for monitoring deterioration of internal combustion engine exhaust gas purifier
Assignee: Hitachi Ltd
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Filing: 1991-08-13
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Granted: —
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Expires: 2011-08-13
Abstract
Abstract A method and apparatus for monitoring deterioration of an internal combustion engine exhaust gas purifier (7) in which first and second sensors (5, 6) are disposed on the upstream and downstream sides respectively of the purifier (7). The sensors (5, 6) are connected to an electronic control unit (9) which, in normal operation, is arranged to control the air-fuel mixture supplied to each cylinder (101) of the engine (100) by controlling the amount of fuel supplied by an injector (2) so that the air-fuel ratio is a predetermined mean value. The air-fuel ratio is changed from one predetermined value to another predetermined value and delay time taken for the second sensor (6) to change its response subsequent to said change is indicative of the condition of the purifier (7) so that deterioration of the purifier (7) may be readily determined. <IMAGE>
Inventors
- 👤 Toshio Manaka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 16:15
CPC Classifications
F; F01; F01N; F01N11/00; F01N11/007; F02; F02D; F02D41/00; F02D41/22; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N9/00; F01N2430/00; F01N2430/06; F01N2550/00; F01N2550/02; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
82 words
A method of monitoring the deterioration of an internal combustion engine exhaust gas purifying means (7), said purifying means (7) being located within an exhaust pipe of said engine, sensor means (6) disposed downstream of said purification means (7), said method characterized by the steps of changing the air-fuel ratio from one predetermined value to another predetermined value and measuring the response time of the sensor means (6) whereby said response time is indicative of the condition of said purifying means (7).
Claim 2
Dependent Claim
81 words
A method as claimed in claim 1 wherein the air-fuel ratio supplied to each cylinder (101) of said engine is measured by a further sensor (5), the output of said further sensor means (5) being used to control the air-fuel ratio of the air-fuel mixture supplied to each cylinder (101) to a predetermined mean value, changing the air-fuel ratio from one predetermined value to another predetermined value so that the air-fuel ratio detected by the said sensor means (6) is varied.
Claim 3
Dependent Claim
34 words
A method as claimed in claim 2 wherein said one predetermined value is on one side of said mean value and said another predetermined value is on an opposite side of said mean value.
Claim 4
Independent Claim
28 words
A method as claimed in any preceding claim wherein the air-fuel mixture is changed from said one predetermined value to said another predetermined value in a step-wise fashion.
Claim 5
Dependent Claim
17 words
A method as claimed in claim 2 wherein said mean value of the air-fuel ratio is 14.7.
Claim 6
Dependent Claim
35 words
A method as claimed in claim 4 wherein said one predetermined value is on the lean side of said mean value and said another predetermined value is on the rich side of said mean value.
Claim 7
Independent Claim
46 words
A method as claimed in any preceding claim wherein the air-fuel mixture predetermined value is changed by modifying one of an integration component (I R , I L ), a proportional component (P R , P L ) or a judgemental level voltage (V SL ).
Claim 8
Independent Claim
118 words
An apparatus for monitoring deterioration of an internal combustion engine exhaust gas purifying means (7) located in an exhaust pipe of said engine (100) including a sensor means (6) disposed downstream of said purifying means (7), and electronic control means (9) for controlling the air-fuel ratio of said engine, characterized by said electronic control means (9) being connected to receive output signals from said sensor means (6) and to measure the time taken for the response of the sensor means (6) to change when the air-fuel ratio is changed from one predetermined value to another predetermined value, whereby said time taken for the sensor means (6) response to change is indicative of the condition of said purifying means.
Claim 9
Dependent Claim
73 words
An apparatus as claimed in claim 8 wherein a further sensor means (5) is provided upstream of said purifying means (7) for detecting the air-fuel mixture supplied to each cylinder (101) of said engine (100) and said electronic control means (9) is adapted to control fuel supplied to each cylinder (101) and in dependence thereon said electronic control means controls the air-fuel mixture supplied to each cylinder (101) to a predetermined mean value.
Claim 10
Dependent Claim
35 words
An apparatus as claimed in claim 9 wherein said electronic control means (9) controls said air-fuel mixture predetermined value to change from said one predetermined value to said another predetermined value in a stepwise fashion.
Claim 11
Independent Claim
19 words
An apparatus as claimed in any of claims 8 to 10 wherein the desired mean air-fuel ratio is 14.7.
Claim 12
Dependent Claim
43 words
An apparatus as claimed in claim 10 wherein said electronic control means (9) controls such that said one predetermined value is on the lean side of said mean value and said another predetermined value is on the rich side of said mean value.
Claim 13
Independent Claim
53 words
An apparatus as claimed in any of claims 8 to 12 wherein said electronic control means (9) changes the air-fuel ratio predetermined value by modifying one of an integration component (I R , I L ), a proportional component (P R , P L ) or a judgemental level voltage (V SL ).
References Cited (Backward Citations)
No citation records indexed.
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