US4587615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for diagnosing an internal combustion engine
Assignee: Subaru Corp
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Filing: 1983-09-26
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Granted: 1986-05-06
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Expires: 2003-09-26
Abstract
Abstract A system for diagnosing an internal combustion engine having engine operation sensing devices. A diagnosing circuit is provided to response to output voltages of the sensing devices for producing a first signal when the voltage exceeds a predetermined range and a second signal with a delay after the first signal. A fail-safe signal generating circuit is provided to produce one of fail-safe signals in dependency on the first signal so as to prevent the stall of the engine. The second signal operated to indicate trouble in the engine operation sensing devices after the fail-safe operation.
Inventors
- 👤 Toshio Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:05
CPC Classifications
G; G07; G07C; G07C5/00; G07C5/08; G07C5/0808; F; F02; F02D; F02D41/00; F02D41/22; F02D41/222; F02D41/24; F02D41/26; F02D41/266; G05; G05B; G05B9/00; G05B9/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
173 words
A system for diagnosing an internal combustion engine comprising: an engine operation sensing device; a diagnosing circuit including a window comparator for producing a first output signal when the output of said sensing device exceeds one of predetermined limit values, and first and second circuit means operatively coupled to said window comparator, said first circuit means producing a second output signal when the first output signal of said comparator continues for a first predetermined time, said second circuit means producing a third output signal when the first output signal continues for a second predetermined time longer than the first predetermined time; a fail-safe signal generating circuit producing a fail-safe signal; switch means responsive to said second output signal of said first circuit means for allowing the fail-safe signal to pass from said fail-safe signal generating circuit; means responsive to said fail-safe signal for producing a quasi signal to maintain the operation of the engine; and an indicator means responsive to said third output signal for indicating trouble in said engine operation sensing device.
Claim 2
Independent Claim
173 words
A system for diagnosing an internal combustion engine comprising: an engine operation sensing device; a diagnosing circuit including a window comparator for producing a first output signal when the output of said sensing device exceeds one of predetermined limit values, and first and second circuit means operatively coupled to said window comparator, said first circuit means producing a second output signal when the first output signal of said comparator continues for a first predetermined time, said second circuit means producing a third output signal when the first output signal continues for a second predetermined time longer than the first predetermined time; a fail-safe signal generating circuit producing a fail-safe signal; switch means responsive to said second output signal of said first circuit means for allowing the fail-safe signal to pass from said fail-safe signal generating circuit; means responsive to said fail-safe signal for producing a quasi signal to maintain the operation of the engine; and an indicator means responsive to said third output signal for indicating trouble in said engine operation sensing device.
Claim 3
Dependent Claim
74 words
The system for diagnosing an internal combustion engine according to claim 1, wherein said comparator is an analog comparator, and said diagnosing circuit comprises means for changing an output signal of said comparator to a train of pulses; said first and said second circuit means comprising counters for counting said pulses of said comparator, each of said counters being adapted to produce an output signal when the counter counts up to a predetermined number.
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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) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |