US5703285A
Expired / Lapsed
US
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Diagnosis apparatus and method for an exhaust gas recirculation unit of an internal combustion engine
Assignee: Hitachi Ltd
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Filing: 1996-07-02
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Granted: 1997-12-30
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Expires: 2016-07-02
Abstract
Abstract A difference is obtained between a cylinder pressure during the compression stroke when an exhaust gas recirculation control valve is opened, and a cylinder pressure during the compression stroke when the exhaust gas recirculation control valve is closed. An estimated value for this difference is set from a cylinder pressure detected under the closed conditions and an exhaust gas recirculation proportion. When the difference is smaller than the estimated value, it is assumed that the exhaust gas recirculation quantity is not changing in accordance with open/close control, and the occurrence of a fault in the exhaust gas recirculation unit is thus judged.
Inventors
- 👤 Hirokazu Shimizu
- 👤 Kenichi Machida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:12
CPC Classifications
F; F02; F02D; F02D35/00; F02D35/02; F02D35/023; F02M; F02M26/00; F02M26/49; F02M26/52; F02M26/55; F02M26/56; F02M26/57
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
135 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the exhaust gas is recirculated back to an intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said apparatus comprising: a cylinder pressure sensor for detecting a cylinder pressure of the engine; cylinder pressure sampling means for sampling the cylinder pressure detected by said cylinder pressure sensor within a pre-set crank angle during a compression stroke; and diagnosis means for outputting a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit, based on the cylinder pressure sampled by said cylinder pressure sampling means and an open/close condition of said exhaust gas recirculation control valve for when said cylinder pressure was sampled.
Claim 2
Dependent Claim
135 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the exhaust gas is recirculated back to an intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said apparatus comprising: a cylinder pressure sensor for detecting a cylinder pressure of the engine; cylinder pressure sampling means for sampling the cylinder pressure detected by said cylinder pressure sensor within a pre-set crank angle during a compression stroke; and diagnosis means for outputting a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit, based on the cylinder pressure sampled by said cylinder pressure sampling means and an open/close condition of said exhaust gas recirculation control valve for when said cylinder pressure was sampled.
Claim 3
Dependent Claim
70 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 1, wherein said diagnosis means outputs a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit based on a difference between a cylinder pressure sampled with said exhaust gas recirculation control valve open, and a cylinder pressure sampled with said exhaust gas recirculation control valve closed.
Claim 4
Dependent Claim
80 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 2, wherein said diagnosis means sets an estimation value for said difference based on an exhaust gas recirculation proportion and the cylinder pressure sampled by said cylinder pressure sampling means, and judges a fault in said exhaust gas recirculation unit when said difference is equal to or less than said estimation value, and outputs a diagnosis signal indicating the occurrence of a fault.
Claim 5
Dependent Claim
95 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 2, wherein said diagnosis means outputs said diagnosis signal to indicate the presence or absence of a fault based on a difference between a cylinder pressure sampled by said cylinder pressure sampling means during said compression stroke with said exhaust gas recirculation control valve open and a cylinder pressure sampled by said cylinder pressure sampling means during said compression stroke with said exhaust gas recirculation control valve closed, thus avoiding an influence of combustion fluctuations on the diagnosis.
Claim 6
Dependent Claim
53 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 2, wherein said diagnosis means computes an average value of said difference and outputs a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit based on said average value.
Claim 7
Dependent Claim
43 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 5, wherein said diagnosis means changes a dead zone for fault judgment, based on a number of difference data used during computation of said average value.
Claim 8
Dependent Claim
47 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 1, wherein said diagnosis means outputs said diagnosis signal based only on the cylinder pressure sampled during a compression stroke, thus avoiding an influence of combustion fluctuations on the diagnosis.
Claim 9
Dependent Claim
35 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 1, wherein said cylinder pressure sampling means samples the cylinder pressure within a range from 30° BTDC˜20° BTDC.
Claim 10
Dependent Claim
59 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 1, wherein said cylinder pressure sampling means computes an average value of the cylinder pressure sampled in a pre-set crank angle range during the compression stroke, and said diagnosis means carries out diagnosis based on said average value of the cylinder pressure.
Claim 11
Dependent Claim
59 words
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine according to claim 1, wherein said cylinder pressure sampling means computes an integral value of the cylinder pressure sampled in a pre-set crank angle range during the compression stroke, and said diagnosis means carries out diagnosis based on said integral value of the cylinder pressure.
Claim 12
Dependent Claim
108 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the exhaust gas is recirculated to an intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said method including: sampling the cylinder pressure detected by a cylinder pressure sensor in a pre-set sampling timing during a compression stroke, and outputting a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit based on the sampled cylinder pressure and an open/close condition of said exhaust gas recirculation control valve for when said cylinder pressure was sampled.
Claim 13
Dependent Claim
108 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the exhaust gas is recirculated to an intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said method including: sampling the cylinder pressure detected by a cylinder pressure sensor in a pre-set sampling timing during a compression stroke, and outputting a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit based on the sampled cylinder pressure and an open/close condition of said exhaust gas recirculation control valve for when said cylinder pressure was sampled.
Claim 14
Dependent Claim
68 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 11, wherein a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit is output based on a difference between a cylinder pressure sampled with said exhaust gas recirculation control valve open, and a cylinder pressure sampled with said exhaust gas recirculation control valve closed.
Claim 15
Dependent Claim
73 words
A diagnosis method for an exhaust gas recirculation Unit of an internal combustion engine according to claim 12, wherein an estimation value for said difference is set based on an exhaust gas recirculation proportion, and said sampled cylinder pressure, a fault in said exhaust gas recirculation unit is judged when said difference is equal to or less than said estimation value, and a diagnosis signal indicating the occurrence of a fault is output.
Claim 16
Dependent Claim
88 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 12, wherein said step of outputting a diagnosis signal comprises outputting said diagnosis signal to indicate the presence or absence of a fault based on a difference between a cylinder pressure sampled during said compression stroke with said exhaust gas recirculation control valve open and a cylinder pressure sampled during said compression stroke with said exhaust gas recirculation control valve closed, thus avoiding an influence of combustion fluctuations on the diagnosis.
Claim 17
Dependent Claim
52 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 12, wherein an average value of said difference is computed and a diagnosis signal indicating the presence or absence of a fault in said exhaust gas recirculation unit is output based on said average value.
Claim 18
Dependent Claim
41 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 15, wherein a dead zone for fault judgment is changed, based on a number of difference data used during computation of said average value.
Claim 19
Dependent Claim
52 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 11, wherein said step of outputting a diagnosis signal comprises outputting said diagnosis signal based only on the cylinder pressure sampled during a compression stroke, thus avoiding an influence of combustion fluctuations on the diagnosis.
Claim 20
Dependent Claim
31 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 11, wherein the cylinder pressure is sampled within a range from 30° BTDC˜20° BTDC.
Claim 21
Dependent Claim
53 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 11, wherein an average value of the cylinder pressure sampled in a pre-set crank angle range during the compression stroke is computed, and diagnosis based on said average value of the cylinder pressure is carried out.
Claim 22
Dependent Claim
53 words
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine according to claim 11, wherein an integral value of the cylinder pressure sampled in a pre-set crank angle range during the compression stroke is computed, and diagnosis based on said integral value of the cylinder pressure is carried out.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-29 | 2001-06-30 | 2001-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-29 | 2005-06-30 | 2005-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-29 | 2009-06-30 | 2009-12-30 | $7700.00 | Window Closed / Lapsed |