US5349816A
Expired / Lapsed
US
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Exhaust emission control system
Assignee: Mitsubishi Motors Corp
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Filing: 1993-02-19
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Granted: 1994-09-27
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Expires: 2013-02-19
Abstract
Abstract An exhaust emission control system for a motor vehicle is disposed in an exhaust path, comprises a first catalyst for purifying an exhaust gas during activation of an engine, a second catalyst disposed downstream of the first catalyst and including a lean NOx catalyst, a bypass detouring the first catalyst, a select valve for controlling the amount of exhaust gas to be introduced into the bypass and first catalyst, and a control unit for controlling the select valve and flow of the exhaust gas according to operating status of the engine.
Inventors
- 👤 Daisuke Sanbayashi
- 👤 Osamu Hirako
- 👤 Yoshiaki Danno
- 👤 Kazuo Koga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:32
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/101; F01N13/00; F01N13/009; F01N13/0093; F01N3/18; F01N3/20; F01N3/2053; F02; F02B; F02B1/00; F02B1/02; F02B1/04; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
123 words
An exhaust emission control system comprising: a) a first catalyst for purifying an exhaust gas at an initial stage of engine operation, the first catalyst being disposed in an exhaust path near an internal combustion engine; b) a second catalyst disposed downstream of the first catalyst, the second catalyst including a lean NOx catalyst for purifying nitrogen of oxides in a lean exhaust gas; a first bypass detouring the first catalyst and converging with the exhaust path upstream of the second catalyst; a first select valve for controlling an amount of exhaust gas to be introduced to the first bypass and the first catalyst; and control means for providing the first select valve with signals indicative of positions of the first select valve.
Claim 2
Dependent Claim
123 words
An exhaust emission control system comprising: a) a first catalyst for purifying an exhaust gas at an initial stage of engine operation, the first catalyst being disposed in an exhaust path near an internal combustion engine; b) a second catalyst disposed downstream of the first catalyst, the second catalyst including a lean NOx catalyst for purifying nitrogen of oxides in a lean exhaust gas; a first bypass detouring the first catalyst and converging with the exhaust path upstream of the second catalyst; a first select valve for controlling an amount of exhaust gas to be introduced to the first bypass and the first catalyst; and control means for providing the first select valve with signals indicative of positions of the first select valve.
Claim 3
Dependent Claim
31 words
An exhaust emission control system of claim 1, wherein the second catalyst includes the lean NOx catalyst and a three way catalyst disposed along a flow direction of the exhaust gas.
Claim 4
Dependent Claim
17 words
An exhaust emission control system of claim 1, wherein the first catalyst is a three way catalyst.
Claim 5
Dependent Claim
16 words
An exhaust emission control system of claim 1, wherein the first catalyst is an oxidation catalyst.
Claim 6
Dependent Claim
43 words
An exhaust emission control system of claim 1, wherein the control means includes an engine non-operation judging means, for controlling the first select valve to a position for opening the first bypass when the engine non-operation judging means judges non-operation of the engine.
Claim 7
Dependent Claim
49 words
An exhaust emission control system of claim 1, wherein the control means includes an engine warm-up completion judging means, for controlling the first select valve to a position for closing the first bypass when the engine warm-up completion judging means judges that the engine has not been warmed up.
Claim 8
Dependent Claim
65 words
An exhaust emission control system of claim 1, wherein the control means includes a first catalyst activation judging means and a second catalyst activation judging means, for controlling the first select valve to an intermediate position when the first catalyst activation judging means recognizes activation of the first catalyst and when the second catalyst activation judging means does not recognize activation of the second catalyst.
Claim 9
Dependent Claim
88 words
An exhaust emission control system of claim 7, wherein the first catalyst activation judging means judges the activation of the first catalyst according to a temperature of the first catalyst or a temperature of the exhaust gas around the first catalyst detected by a first catalyst temperature sensor, and the second catalyst activation judging means judges the activation of the second catalyst according to a temperature of the second catalyst or a temperature of the exhaust gas around the second catalyst detected by a second catalyst temperature sensor.
Claim 10
Dependent Claim
78 words
An exhaust emission control system of claim 7, wherein the second catalyst activation judging means judges the activation of the second catalyst according to a temperature of the second catalyst or a temperature of the exhaust gas around the second catalyst detected by the second catalyst temperature sensor, and the first catalyst activation judging means judges the activation of the first catalyst according to a differential value of a temperature value detected by the second catalyst temperature sensor.
Claim 11
Dependent Claim
81 words
An exhaust emission control system according to claim 1, wherein the control means includes a lean air/fuel ratio judging means, for controlling the first select valve to a position for opening the first bypass when the engine is operating on a lean air/fuel mixture, and control the first select valve to a position for introducing the exhaust gas into the first catalyst when the engine is operating on an air/fuel mixture having an air/fuel ratio other than the lean air/fuel ratio.
Claim 12
Dependent Claim
28 words
An exhaust emission control system according to claim 1, wherein the control means controls the first select valve according to time lapse after the operation of the engine.
Claim 13
Dependent Claim
64 words
An exhaust emission control system of claim 1, further comprising a second bypass detouring the lean NOx catalyst in the second catalyst and converging the exhaust path, and a second select valve for controlling the amount of exhaust gas to be introduced to the second bypass or the lean NOx catalyst, wherein the control means controls positions of the first and second select valves.
Claim 14
Dependent Claim
65 words
An exhaust emission control system of claim 12, wherein the control means includes a lean air/fuel ratio judging means, for controlling the first select valve to a position for opening the first bypass and controls the second select valve to a position for closing the second bypass when the lean air/fuel ratio judging means recognizes that the engine is operating on a lean air/fuel mixture.
Claim 15
Dependent Claim
57 words
An exhaust emission control system of claim 12, wherein the control means includes an engine non-operation judging means, for controlling the first select valve to a position for opening the first bypass and controls the second select valve to a position for closing the second bypass when the engine non-operation judging means judges non-operation of the engine.
Claim 16
Dependent Claim
67 words
An exhaust emission control system of claim 12, wherein the control means includes a second catalyst temperature sensor for detecting a temperature of the lean NOx catalyst or a temperature of exhaust gas around the lean NOx catalyst, and controls the second select valve to a position for opening the second bypass when a temperature detected by the second catalyst temperature sensor is above a predetermined value.
Claim 17
Dependent Claim
20 words
An exhaust emission control system of claim 1, wherein the first select valve is disposed upstream of the first catalyst.
Claim 18
Dependent Claim
86 words
An exhaust emission control system of claim 1, further comprising: an air actuator which drives the first select valve and includes the air actuator including a negative pressure chamber, a diaphragm coupled to the first select valve and a return spring for pushing the diaphragm; and a valve which raises a negative pressure in the negative pressure chamber, closes the first bypass against a force of the return spring and controls supply of the negative pressure in response to a control signal from the control means.
Claim 19
Dependent Claim
45 words
An exhaust emission control system of claim 17, wherein the valve releases the negative chamber to the atmosphere when the engine is non-operated or when no control signal arrives, and the first select valve opens the first bypass by the force of the return spring.
References Cited (Backward Citations)
US3440817A
Cited
US4510749A
Cited
US4817385A
Cited
US5060473A
Cited
EP0406507A1
Cited
US5085050A
Cited
EP0433772A2
Cited
JPH03225013A
Cited
DE9004614U1
Cited
US5233830A
Cited
JPH0435724A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-26 | 1998-03-28 | 1998-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-26 | 2002-03-28 | 2002-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-26 | 2006-03-28 | 2006-09-27 | $7700.00 | Window Closed / Lapsed |