US3794006A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Egr warning system
Assignee: Ford Motor Co
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Filing: 1972-12-05
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Granted: 1974-02-26
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Expires: 1992-12-05
Abstract
Abstract An exhaust gas recirculation system for an internal combustion engine is provided with a warning system for indicating to the driver of a vehicle a failure of recirculation. The warning system employs series switches to control an electrical circuit for energizing an indicator; one switch is subject to an engine vacuum signal serving also to control admission of exhaust gas recirculation. Another switch is subject to differential pressures on opposite sides of a restrictor in the recirculation flow to sense a failure of recirculation.
Inventors
- 👤 G Woodward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:16
CPC Classifications
F; F02; F02M; F02M26/00; F02M26/65; F02M26/66; F02M26/68; F02M26/45; F02M26/46; F02M26/47; F02M26/49; F02M26/52; F02M26/55; Y; Y10; Y10T; Y10T137/00; Y10T137/8158; Y10T137/8326
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
187 words
A warning system for indicating malfunction of exhaust gas recirculation which is adapted to return exhaust gases from an exhaust manifold to the intake manifold of an internal combustion engine, the combination comprising: a. means defining a limiting orifice through which said exhaust gas recirculation must flow; b. means responsive to predetermined conditions of said engine to admit recirculation flow; c. flow responsive means having an actuator normally biased in one direction and urged in an opposite direction by the combination of both exhaust manifold pressure and intake manifold vacuum pressure during substantial exhaust gas recirculation; d. a signal means to indicate failure of said recirculation; e. control means operably interconnecting said flow responsive means and admitting means with said signal means, said control means having a first control element responsive to movement of said actuator in said opposite direction idicative of the absence of exhaust gas recirculation for permitting energization of said signal means, and a second control element in series with said first control element permitting energization of said signal means only when said flow admitting means is operative to permit recirculation of exhaust gases.
Claim 2
Dependent Claim
187 words
A warning system for indicating malfunction of exhaust gas recirculation which is adapted to return exhaust gases from an exhaust manifold to the intake manifold of an internal combustion engine, the combination comprising: a. means defining a limiting orifice through which said exhaust gas recirculation must flow; b. means responsive to predetermined conditions of said engine to admit recirculation flow; c. flow responsive means having an actuator normally biased in one direction and urged in an opposite direction by the combination of both exhaust manifold pressure and intake manifold vacuum pressure during substantial exhaust gas recirculation; d. a signal means to indicate failure of said recirculation; e. control means operably interconnecting said flow responsive means and admitting means with said signal means, said control means having a first control element responsive to movement of said actuator in said opposite direction idicative of the absence of exhaust gas recirculation for permitting energization of said signal means, and a second control element in series with said first control element permitting energization of said signal means only when said flow admitting means is operative to permit recirculation of exhaust gases.
Claim 3
Dependent Claim
98 words
The warning system as in claim 1, in which said actuator comprises a diaphragm normally biased in one direction and having one side of the diaphragm subject to the pressure of sAid recirculation flow immediately upstream from said orifice and the other side of said diaphragm subject to the pressure of said recirculation flow immediately downstream of said orifice, whereby during recirculation the differential between said pressures is effective to overcome said bias and during a failure of said recirculation the differential between said pressures is effective to operate said first control element for energizing said signal means.
Claim 4
Dependent Claim
75 words
A warning system as in claim 1, in which said admitting means comprises a valve movable between positions to permit or prevent exhaust gas recirculation, a first diaphragm assembly having a diaphragm normally biased in one direction and subject to a vacuum signal from said engine for urging said diaphragm in an opposite direction, said second control element being responsive to the operative positioning of said diaphragm for determining an open or closed position thereof.
Claim 5
Dependent Claim
50 words
The combination as in claim 3, in which said engine has a carburetor with a port arranged to communicate a vacuum signal which is non-existent at closed or wide-open throttle conditions of said carburetor, means connecting said port with said diaphragm assembly to subject said diaphragm to said vacuum signal.
Claim 6
Dependent Claim
47 words
The combination as in claim 3, in which a second diaphragm assembly is employed in parallel with said first diaphragm assembly, said first assembly operating to directly effect the positioning of said valve and said second assembly operating to directly effect positioning of said second control element.
Claim 7
Dependent Claim
63 words
The warning system as in claim 1, in which said signal means comprises a visual indicator normally energized by an electrical circuit with said control elements comprising electrical switches in said circuit, said signal means further comprising a time delay means in said circuit effective to energize said indicator only after a predetermined time has elapsed from when both said switches are closed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |