US3766895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric speed control system and more-than-two-state phase detector suitable for use therein
Assignee: Ambac Industries Inc
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Filing: 1971-08-13
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Granted: 1973-10-23
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Expires: 1991-08-13
Abstract
Abstract An engine speed electric governer employing a more-than-twostate phase detector to generate the control signal for holding the engine speed at a predetermined nominal value corresponding to a null voltage level produced by one of the interior states of a more-than-two-state phase detector (typically a three-state detector), whereby the output of the phase detector during normal locked-in operation comprises a DC voltage plus only very narrow pulses of low duty cycle and the filtering of the phase detector output is simplified. On occasions when a sudden load change causes the engine speed to change enough to prevent lock-in of the detector, the detector produces an unambiguous electrical signal for returning the engine speed to the lock-in range. The phase detector preferably comprises a differential-input operational amplifier having an inverting input terminal and a non-inverting input terminal, a direct-coupled negative feedback circuit from the output terminal thereof to the inverting input terminal, and a direct-coupled positive feedback circuit which is connected between the output terminal and the non-inverting input terminal when the output voltage of the amplifier lies outside a central range in either direction but which is disconnected by the action of appropriately biased diode-rectifiers when the output voltage is in the central range.
Inventors
- 👤 J Voss
- 👤 W Ferry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:20
CPC Classifications
F; F02; F02D; F02D31/00; F02D31/001; F02D31/007
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
236 words
An electric governor system for an engine, comprising: pickup means responsive to operation of said engine for producing a first series of short pulses in phase with said engine operation; a more-than-two-state phase detector supplied with said first series of pulses; a voltage controlled oscillator for producing an output signal having a frequency determined by a control voltage supplied thereto; means for deriving from the output of said voltage controlled oscillator a second series of pulses in phase with said output signal and for applying said second series of pulses to said phase detector; each pulse of one Of said first and second series moving said phase detector to its next higher stable state, and each pulse of the other of said first and second series moving said phase detector to its next lower stable state; low-pass filter means supplying the output of said phase detector to said voltage controlled oscillator as a control voltage to vary the frequency thereof in the sense to produce a phase-locked condition when said first and second series of pulses are near each other in frequency; fuel control means variable in response to a varying control signal to vary controlledly the rate of supply of fuel to said engine; and means for deriving a signal varying in accordance with the average of said phase detector output and for applying it to determine the control signal for said fuel control means.
Claim 2
Dependent Claim
236 words
An electric governor system for an engine, comprising: pickup means responsive to operation of said engine for producing a first series of short pulses in phase with said engine operation; a more-than-two-state phase detector supplied with said first series of pulses; a voltage controlled oscillator for producing an output signal having a frequency determined by a control voltage supplied thereto; means for deriving from the output of said voltage controlled oscillator a second series of pulses in phase with said output signal and for applying said second series of pulses to said phase detector; each pulse of one Of said first and second series moving said phase detector to its next higher stable state, and each pulse of the other of said first and second series moving said phase detector to its next lower stable state; low-pass filter means supplying the output of said phase detector to said voltage controlled oscillator as a control voltage to vary the frequency thereof in the sense to produce a phase-locked condition when said first and second series of pulses are near each other in frequency; fuel control means variable in response to a varying control signal to vary controlledly the rate of supply of fuel to said engine; and means for deriving a signal varying in accordance with the average of said phase detector output and for applying it to determine the control signal for said fuel control means.
Claim 3
Dependent Claim
23 words
The governor system of claim 1, comprising integrator means connected between the output terminals of said phase detector and said fuel control means.
Claim 4
Dependent Claim
57 words
The governor system of claim 2, wherein said system is operative to maintain the speed of said engine at a predetermined reference speed, and the null value of the average of said phase detector output for which said reference speed is produced is substantially equal to the level of an interior stable state of said phase detector.
Claim 5
Dependent Claim
56 words
The governor system of claim 1, wherein said system is operative to maintain the speed of said engine at a predetermined reference speed, and the null value of the average of said phase detector output for which said reference speed is produced is substantially equal to the level of an interior state of said phase detector.
Claim 6
Dependent Claim
16 words
The governor of claim 1, in which said more-than-two-state phase detector is a three-state phase detector.
Claim 7
Dependent Claim
25 words
The governor system of claim 1, comprising gain-control means for manually adjusting the gain afforded to said control signals applied to said voltage controlled oscillator.
Claim 8
Dependent Claim
200 words
The governor system of claim 1, in which said more-than-two-state phase detector comprises: an amplifying circuit having an output terminal, a non-inverting input terminal, and an inverting input terminal; a direct-coupled negative feedback path connecting said output terminal to said inverting input terminal; a direct-coupled positive feedback path connecting said output terminal to said non-inverting input terminal; means for causing said negative feedback path to provide negative feedback stronger than the positive feedback produced by said positive feedback path when the voltage at said output terminal is within a predetermined range thereby to provide a first stable interior state for said phase detector, and for causing said positive feedback to exceed said negative feedback when said voltage of said output terminal is in either of two other ranges on opposite sides of said predetermined range thereby to provide two other stable states for said phase detector on opposite sides of said first stable state; and means for applying pulse signals to at least one of said input terminals for switching said voltage at said output terminal between said predetermined range and said other ranges thereby to switch said phase detector between said first stable state and said other stable states.
Claim 9
Dependent Claim
47 words
The detector of claim 7, comprising electronic switch means for effectively opening said positive feedback path when said voltage at said output terminal is in said predetermined range and for closing said positive feedback path when said voltage at said output terminal is outside said predetermined range.
Claim 10
Dependent Claim
63 words
The detector of claim 8, in which said electronic switching means comprises unilaterally-conductive means connecting said positive feedback path to said output terminal, and means for biasing said unilaterally-conductive means in a conductive state when the voltage at said output terminal is outside said predetermined range and in a non-conductive state when said voltage at said output terminal is within said predetermined range.
Claim 11
Dependent Claim
39 words
The detector of claim 7, in which said pulse signals have a predetermined decay time constant, and in which said negative feedback path comprises capacitive means providing a decay time-constant slightly longer than the decay time-constant of said pulses.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |