US4307689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glow plug control circuit
Assignee: Federal Mogul Ignition LLC
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Filing: 1980-08-25
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Granted: 1981-12-29
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Expires: 2000-08-25
Abstract
Abstract Switch-controlled apparatus for actuating a power switch to enable application of power from an associated power supply to a heater filament of a glow plug in a diesel engine is disclosed. The filament is one which is heated to a predetermined design temperature when a specified voltage is applied thereto. The power source has a supply voltage greater than the specified voltage of the filament. A switch accessible to an operator of the engine is operable in a first position to prevent the application of the supply voltage to the apparatus, operable in a second position to apply the supply voltage through a first terminal of the apparatus, and operable in a third position to apply the supply voltage through the first terminal and through a second terminal of the apparatus and to a starter for the engine. The apparatus comprises means operable, after the switch has been turned from the first to the second position, to actuate the power switch for a preheat time period which varies as an inverse function of available supply voltage and equals the time required to raise the temperature of the filament from ambient temperature to the design temperature. The apparatus also includes means operable, after the preheat time period, to alternately actuate and then deactuate the power switch in a cyclic fashion to maintain the design temperature of the filament for a prestart time period. The apparatus also includes means operable, after turning the switch from the second to the third position, to continue the cyclical actuation and deactuation of the power switch for an afterglow time period predetermined by the amount of time required for smooth engine idling and to minimize engine noise and white smoke emission.
Inventors
- 👤 Frank J. Raeske
- 👤 Robert A. Mahaney
- 👤 Richard E. Callahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:54
CPC Classifications
F; F02; F02P; F02P19/00; F02P19/02; F02P19/021; F02P19/022; F02B; F02B3/00; F02B3/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
299 words
Apparatus controlled by an ignition switch for energizing a normally-open power switch to enable application of power from an associated power source to a heater filament of a glow plug in a diesel engine, the filament being one which is heated to a predetermined design temperature when a specified voltage is applied thereto, the power source having a supply voltage greater than the specified voltage, the ignition switch being operable in a first position to prevent the application of the supply voltage to the apparatus, operable in a second position to apply the supply voltage at a first terminal of the apparatus, and operable in a third position to apply the supply voltage at the first terminal and at a second terminal of the apparatus and to the starter for the engine, the ignition switch further being operable, when turned to the third position and released, to return to the second position, said apparatus comprising: means operable, after the ignition switch has been turned from the first to the second position, to energize the power switch to cause preheating of the filament for a time period which varies as an inverse function of available supply voltage and equals the time required to raise the temperature of the filament from ambient temperature to the design temperature, means operable, after the preheat time period, to maintain the filament at the design temperature for a prestart time period by alternately energizing and then de-energizing the power switch in repetitive fashion, and means operable, after the ignition switch has been turned from the second to the third position, to continue alternately energizing and then de-energizing the power switch for an afterglow time period predetermined by the amount of time required for smooth engine idling and to minimize engine noise and white smoke emission.
Claim 2
Dependent Claim
299 words
Apparatus controlled by an ignition switch for energizing a normally-open power switch to enable application of power from an associated power source to a heater filament of a glow plug in a diesel engine, the filament being one which is heated to a predetermined design temperature when a specified voltage is applied thereto, the power source having a supply voltage greater than the specified voltage, the ignition switch being operable in a first position to prevent the application of the supply voltage to the apparatus, operable in a second position to apply the supply voltage at a first terminal of the apparatus, and operable in a third position to apply the supply voltage at the first terminal and at a second terminal of the apparatus and to the starter for the engine, the ignition switch further being operable, when turned to the third position and released, to return to the second position, said apparatus comprising: means operable, after the ignition switch has been turned from the first to the second position, to energize the power switch to cause preheating of the filament for a time period which varies as an inverse function of available supply voltage and equals the time required to raise the temperature of the filament from ambient temperature to the design temperature, means operable, after the preheat time period, to maintain the filament at the design temperature for a prestart time period by alternately energizing and then de-energizing the power switch in repetitive fashion, and means operable, after the ignition switch has been turned from the second to the third position, to continue alternately energizing and then de-energizing the power switch for an afterglow time period predetermined by the amount of time required for smooth engine idling and to minimize engine noise and white smoke emission.
Claim 3
Dependent Claim
44 words
Apparatus as recited in claim 1 which additionally includes signal means operable to energize a sensory signal when the supply voltage is applied thereto, wherein said first-named means is operable to apply the supply voltage to said signal means for the preheat time period.
Claim 4
Dependent Claim
128 words
Apparatus as recited in claim 2, wherein said power switch energizing means comprises: switching means operable, when activated, to energize and, when deactivated, to deenergize the power switch, means operable, when the supply voltage is applied at the first terminal of said apparatus, to establish a reference current and a trigger current which increases in magnitude at a rate varying as a proportional function of the available supply voltage from below to above that of the reference current, and a first comparator operable to cause preheating by activating said switching means when the magnitude of the trigger current is less than that of the reference current, and to terminate preheating by deactivating said switching means when the magnitude of the trigger current exceeds that of the reference current.
Claim 5
Dependent Claim
125 words
Apparatus as recited in claim 3, wherein said means operable to maintain filament temperature comprises: an astable multivibrator operably associated to be enabled by said first comparator when the magnitude of the trigger current exceeds that of the reference current, and operable, when enabled, to activate and then deactivate said switching means in repetitive fashion, means operably associated to be enabled by said first comparator when the magnitude of the trigger current exceeds that of the reference current, and operable when enabled, to establish a fixed current and a variable current which increases in magnitude from below to above that of the fixed current, and a second comparator operable to disable said multivibrator when the magnitude of the variable current exceeds that of fixed current.
Claim 6
Dependent Claim
33 words
Apparatus as recited in claim 4 which additionally includes means operable to vary the magnitude of the reference current as an inverse function of the deviation of engine temperature from a reference temperature.
Claim 7
Dependent Claim
204 words
Apparatus as recited in claim 1 which additionally includes signal means operable to energize a sensory signal when the supply voltage is applied thereto, wherein said power switch energizing means is operable to apply the supply voltage to said signal means for the preheat time period, and wherein said power switching energizing means comprises: switching means operable, when activated, to energize and, when deactivated, to deenergize the power switch, a preheat flip-flop having set and reset input terminals and an output terminal connected to said switching means, means operable, when the supply voltage is applied at the first terminal of said apparatus, to apply a signal to the set terminal of said preheat flip-flop activating said switching means, oscillator means for establishing pulses at a repetition frequency which varies as a proportional function of the available supply voltage being applied thereto when the supply voltage is applied at the first terminal of said apparatus, and a master counter operably connected to receive pulses from said oscillator means and operable, after receiving a first predetermined number of pulses over a period of time which equals the preheat time period, to apply a signal at the reset terminal of said preheat flip-flop deactivating said switching means.
Claim 8
Dependent Claim
115 words
Apparatus as recited in claim 6, wherein said means operable to maintain filament temperature comprises: a flip-flop operably connected, in response to a signal from said master counter, to activate said switching means, and a counter operable, in response to a predetermined number of signals from said master counter, to deactivate said switching means, and wherein said master counter, after it has deactivated said switching means at the end of the preheat time period, is operable alternately to apply a signal to said flip-flop in response to a second predetermined number of pulses from said oscillator and to apply successive signals to said counter in response to third predetermined numbers of pulses from said oscillator.
Claim 9
Dependent Claim
41 words
Apparatus as recited in claim 7, wherein said master counter, after receiving a predetermined number of pulses, is operable to disable said oscillator means and to apply a signal at a reset terminal of said flip-flop to deactivate said switching means.
Claim 10
Dependent Claim
44 words
Apparatus as recited in claim 8 which additionally includes means operable, after the ignition switch has been turned from the second to the first position, to prevent energization of the power switch by said power switch energizing means for a predetermined period of time.
Claim 11
Dependent Claim
30 words
Apparatus as recited in claim 9 wherein said means named third in claim 1 is not operable until the ignition switch has returned from the third to the second position.
Claim 12
Dependent Claim
36 words
Apparatus as recited in claim 1 wherein said second-named means varies the ratio of the time the power switch is energized to the time it is deenergized as an inverse function of the available supply voltage.
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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) | 1984-12-28 | 1985-06-29 | 1985-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-28 | 1989-06-29 | 1989-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-28 | 1993-06-29 | 1993-12-29 | $7700.00 | Window Closed / Lapsed |