US5209212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust-gas recirculation system for an internal combustion engine
Assignee: Robert Bosch GmbH
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Filing: 1992-06-04
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Granted: 1993-05-11
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Expires: 2012-06-04
Abstract
Abstract An exhaust-gas recirculation system includes means for diagnosing the system based upon temperature values measured in the exhaust-gas return duct when certain conditions exist. A differential value between the actual temperature in the exhaust-gas return duct and a reference temperature, which indicates the possible beginning of diagnosis, is provided for a flow-through test. The differential value is then fed to a low-pass filter. If the conditions for a diagnosis are satisfied, it is determined whether the recirculation system is in order based upon a comparison of the differential value to a threshold value. A leak test of the exhaust-gas return valve can likewise be performed based upon the differential value of the two temperatures.
Inventors
- 👤 Walter Viess
- 👤 Hans Koehnle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:11
CPC Classifications
F; F02; F02M; F02M26/00; F02M26/49; F02D; F02D41/00; F02D41/0025; F02D41/0047; F02D41/0065; F02D2041/0067; F02M26/52; F02M26/55; F02M26/56; F02M26/57
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
172 words
An exhaust-gas recirculation system for an internal combustion engine, comprising: an exhaust-gas return valve located in an exhaust-gas return duct; a load sensor for measuring at least one operating parameter of the internal combustion engine; a temperature sensor for measuring a temperature in the exhaust-gas return duct; a control unit coupled to the load sensor for controlling the exhaust-gas return valve based upon the measured operating parameters; means for determining a difference value between the measured temperature value in the exhaust-gas return duct and a preselected reference value; filter means for receiving a first variable based upon at least one of a measured load of the engine and a trigger signal of the exhaust-gas return valve, for receiving a second variable based upon the difference value, and for generating a filtered output value based thereon; and means for comparing the filtered output value to a first preselected threshold value and for performing a diagnosis of the exhaust-gas recirculation system based thereon by comparing the difference value to a second preselected threshold value.
Claim 2
Dependent Claim
172 words
An exhaust-gas recirculation system for an internal combustion engine, comprising: an exhaust-gas return valve located in an exhaust-gas return duct; a load sensor for measuring at least one operating parameter of the internal combustion engine; a temperature sensor for measuring a temperature in the exhaust-gas return duct; a control unit coupled to the load sensor for controlling the exhaust-gas return valve based upon the measured operating parameters; means for determining a difference value between the measured temperature value in the exhaust-gas return duct and a preselected reference value; filter means for receiving a first variable based upon at least one of a measured load of the engine and a trigger signal of the exhaust-gas return valve, for receiving a second variable based upon the difference value, and for generating a filtered output value based thereon; and means for comparing the filtered output value to a first preselected threshold value and for performing a diagnosis of the exhaust-gas recirculation system based thereon by comparing the difference value to a second preselected threshold value.
Claim 3
Dependent Claim
16 words
The system as recited in claim 1, wherein the second variable is dependent upon an altitude.
Claim 4
Dependent Claim
20 words
The system as recited in claim 1, wherein the preselected reference value is dependent upon the temperature of the engine.
Claim 5
Dependent Claim
39 words
The system as recited in claim 1, wherein the filtered output value is determined according to the following expression: A/B+((B-1)/B)*alt where A refers to the first variable, B refers to the second variable, and alt refers to an altitude.
Claim 6
Dependent Claim
15 words
The system as recited in claim 1, further comprising means for weighing the difference value.
Claim 7
Dependent Claim
25 words
The system as recited in claim 1, further comprising means for performing a leak test on the exhaust-gas return valve based upon the difference value.
Claim 8
Dependent Claim
15 words
The system as recited in claim 1, wherein the filter means is a low-pass filter.
References Cited (Backward Citations)
US3850151A
Cited
US4060065A
Cited
US4531499A
Cited
JPS58197461A
Cited
DE3220832A1
Cited
US4793318A
Cited
US4870941A
Cited
DE3828477A1
Cited
JPS6470749A
Cited
US4967717A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-10 | 1996-11-09 | 1997-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-10 | 2000-11-09 | 2001-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-10 | 2004-11-09 | 2005-05-11 | $7700.00 | Window Closed / Lapsed |