Patent US4494162A successfully refreshed from Google Patents.
US4494162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Starter thermal overload protection system
Assignee: Enviri Corp
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Filing: 1981-10-30
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Granted: 1985-01-15
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Expires: 2001-10-30
Abstract
Abstract A system for protecting the starter of an internal combustion engine from overheating as a result of cranking for an excessive period of time when the engine is difficult to start. Override circuitry is electrically interposed between a manually operable starter switch and the engine starter to apply a prescribed ON and OFF cranking sequence to the starter and thereby limit the duty cycle even though the operator continuously operates the switch. Preferably, the overall maximum duration of the start attempt (the duration of the ON and OFF cranking sequence) is limited by termination circuitry. The ON and OFF cranking intervals and, optionally, the overall maximum duration of the start attempt are particularly selected so as to allow sufficient time for motor winding heat to dissipate into the starter housing. This limited cranking duty cycle protects the starter from overheating. Also, when employed in combination with a thermostatic switch mounted on the starter housing and arranged to prevent starter energization when a predetermined temperature is reached, the limited starter ON time and intermediate resting periods permit the housing and the thermostatic switch to more closely follow winding temperature. As a further aspect, in order to maintain optimum operation of the protection system as starter load conditions vary, starter current is sensed and the starter ON/OFF duty cycle is appropriately modified in response.
Inventors
- 👤 Francis R. Eyler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:40
CPC Classifications
F; F02; F02N; F02N11/00; F02N11/10; H; H02; H02H; H02H3/00; H02H3/08; H02H3/087; H02H7/00; H02H7/08; H02H7/085; H02H7/0856; H02H7/0859
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
In an internal combustion engine starting system of the type including a power source, an electric starter including motor windings within a housing, and a manually operable starter switch for selectively energizing the starter from the power source, a device for protecting the electric starter from overheating during extended cranking periods, said device comprising: override circuitry electrically interposed between the starter switch and the starter, said override circuitry arranged to limit energization of the starter and consequent engine cranking to a predetermined timing sequence of alternating ON intervals and OFF intervals even though the operator continuously operates the starter switch, the predetermined timing sequence being selected so as to allow sufficient time for motor winding heat to dissipate into the starter housing to prevent excessive winding temperatures, and current sensing circuitry for sensing current drawn by the electric starter and for modifying the ON to OFF time ratio of said override circuitry as an inverse function of sensed starter current.
Claim 2
Dependent Claim
160 words
In an internal combustion engine starting system of the type including a power source, an electric starter including motor windings within a housing, and a manually operable starter switch for selectively energizing the starter from the power source, a device for protecting the electric starter from overheating during extended cranking periods, said device comprising: override circuitry electrically interposed between the starter switch and the starter, said override circuitry arranged to limit energization of the starter and consequent engine cranking to a predetermined timing sequence of alternating ON intervals and OFF intervals even though the operator continuously operates the starter switch, the predetermined timing sequence being selected so as to allow sufficient time for motor winding heat to dissipate into the starter housing to prevent excessive winding temperatures, and current sensing circuitry for sensing current drawn by the electric starter and for modifying the ON to OFF time ratio of said override circuitry as an inverse function of sensed starter current.
Claim 3
Dependent Claim
188 words
In an internal combustion engine starting system of the type including a power source, and electric starter including motor windings within a housing, a thermostatic switch mounted on the starter housing and connected to prevent starter energization when a predetermined temperature is reached, and a manually operable starter switch for selectively energizing the starter from the power source, a device for permitting the thermostatic switch to more closely follow winding temperature during extended cranking periods, said device comprising: override circuitry electrically interposed between the starter switch and the starter, said override circuitry arranged to limit energization of the starter and consequent engine cranking to a predetermined timing sequence of alternating ON intervals and OFF intervals even though the operator continuously operates the start switch, the predetermined timing sequence being selected so as to allow sufficient time for motor winding heat to dissipate into the starter housing such that starter housing temperature better follows winding temperature; and current sensing circuitry for sensing current drawn by the electric starter and for modifying the ON to OFF time ratio of said override circuitry as an inverse function of sensed starter current.
Claim 4
Dependent Claim
188 words
In an internal combustion engine starting system of the type including a power source, and electric starter including motor windings within a housing, a thermostatic switch mounted on the starter housing and connected to prevent starter energization when a predetermined temperature is reached, and a manually operable starter switch for selectively energizing the starter from the power source, a device for permitting the thermostatic switch to more closely follow winding temperature during extended cranking periods, said device comprising: override circuitry electrically interposed between the starter switch and the starter, said override circuitry arranged to limit energization of the starter and consequent engine cranking to a predetermined timing sequence of alternating ON intervals and OFF intervals even though the operator continuously operates the start switch, the predetermined timing sequence being selected so as to allow sufficient time for motor winding heat to dissipate into the starter housing such that starter housing temperature better follows winding temperature; and current sensing circuitry for sensing current drawn by the electric starter and for modifying the ON to OFF time ratio of said override circuitry as an inverse function of sensed starter current.
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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) | 1988-01-15 | 1988-07-16 | 1989-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-15 | 1992-07-16 | 1993-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-15 | 1996-07-16 | 1997-01-15 | $7700.00 | Window Closed / Lapsed |