US3915747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse width modulated fuel control for fuel cells
Assignee: RTX Corp
•
Filing: 1973-11-27
•
Granted: 1975-10-28
•
Expires: 1993-11-27
Abstract
Abstract The injection of fuel into a fuel cell hydrogen generator is controlled by the actuation of a fuel injector valve in response to a pulse width modulated square wave as a function of fuel cell stack operation. The off time of the fuel injector valve is fixed at a constant value by comparison of a ramp voltage produced by a first integrator with a constant reference voltage. The on time of the fuel injector valve is variable and is determined by comparing a ramp voltage from a second integrator with a variable voltage which is a function of fuel stack voltage and fuel cell gross current. A fail-safe circuit is incorporated to insure that the fuel injector does not remain in a continuous on or off state if a malfunction occurs in the control circuitry.
Inventors
- 👤 Warren S Summers
- 👤 Salvatore Fanciullo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:36
CPC Classifications
H; H01; H01M; H01M8/00; H01M8/06; H01M8/0606; H01M8/0612; C; C01; C01B; C01B3/00; C01B3/02; C01B3/22; C01B3/24; H01M8/04; H01M8/04298; H01M8/04694; H01M8/04746; H01M8/04776; C01B2203/00; C01B2203/06; C01B2203/066; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
125 words
IN A HYDROGEN GENERATOR FOR SUPPLYING HYDROGEN TO A FUEL CELL, A CONTROL FOR REGULATING THE FLOW OF FUEL INTO SAID HYDROGE GENERATOR TO MAINTAIN A SELECTED PERFORMANCE LEVEL OF SAID FUEL CELL COMPRISING A CONSTANT AREA INJECTOR VALVE POSITIONED IN THE FUEL FLOW PATH, MEANS FOR CYCLICALLY MODULATING SAID VALVE BETWEEN A FULLY OPENED AND A FULLY CLOSED POSITION, MEANS RESPONSIVE TO THE POWER PRODUCED IN SAID FUEL CELL FOR PRODUCING A CONTROL SIGNAL, A FIRST INTEGRATOR PRODUCING A REFERENCE SIGNAL, COMPARATOR MEANS FOR COMPARING SAID CONTROL SIGNAL WITH SAID REFERENCE SIGNAL AND PRODUCING IN RESPONSE THERETO A FIRST ACTUATING SIGNAL, MEANS CONNECTING SAID FIRST ACTUATING SIGNAL WITH SAID CYCLIC MODULATING MEANS FOR VARYING THE TIME THAT SAID VALVE IS OPEN DURING EACH CYCLE,
Claim 2
Dependent Claim
125 words
IN A HYDROGEN GENERATOR FOR SUPPLYING HYDROGEN TO A FUEL CELL, A CONTROL FOR REGULATING THE FLOW OF FUEL INTO SAID HYDROGE GENERATOR TO MAINTAIN A SELECTED PERFORMANCE LEVEL OF SAID FUEL CELL COMPRISING A CONSTANT AREA INJECTOR VALVE POSITIONED IN THE FUEL FLOW PATH, MEANS FOR CYCLICALLY MODULATING SAID VALVE BETWEEN A FULLY OPENED AND A FULLY CLOSED POSITION, MEANS RESPONSIVE TO THE POWER PRODUCED IN SAID FUEL CELL FOR PRODUCING A CONTROL SIGNAL, A FIRST INTEGRATOR PRODUCING A REFERENCE SIGNAL, COMPARATOR MEANS FOR COMPARING SAID CONTROL SIGNAL WITH SAID REFERENCE SIGNAL AND PRODUCING IN RESPONSE THERETO A FIRST ACTUATING SIGNAL, MEANS CONNECTING SAID FIRST ACTUATING SIGNAL WITH SAID CYCLIC MODULATING MEANS FOR VARYING THE TIME THAT SAID VALVE IS OPEN DURING EACH CYCLE,
Claim 3
Dependent Claim
35 words
A control as in claim 1 in which said means responsive to the power produced in said fuel cell includes means responsive to the gross current and the output voltage generated in said fuel cell.
Claim 4
Dependent Claim
109 words
A control as in claim 1 in which said means for cyclically modulating said valve includes a bistable signal generator producing an output signal which alternately varies between a first signal level and a second signal level, said valve being maintained in its open position when said output signal is at said first signal level and in its closed position when said output signal is at saId second signal level, said bistable signal generator being responsive to said first actuating signal for varying the time duration of said first signal level, and being responsive to said second actuating signal for controlling the time duration of said second signal level.
Claim 5
Dependent Claim
92 words
A control as in claim 3 in which the reference signal produced by said first integrator is a first ramp voltage, means for actuating said integrator when the output signal from said bistable signal generator is at its first signal level, said comparator producing said first actuating signal when the magnitude of said first ramp voltage exceeds the magnitude of said control signal, and trigger means responsive to the occurrence of said first actuating signal for causing the output signal from said bistable signal generator to switch to said second signal level.
Claim 6
Dependent Claim
47 words
A control as in claim 4 in which said means for producing said second actuating signal includes a second integrator producing a second ramp voltage, a source of constant voltage, and means for comparing said constant voltage with the second ramp voltage produced by said second integrator.
Claim 7
Dependent Claim
49 words
A control as in claim 5 and including means for actuating said second integrator when said output signal is at said second signal level, said trigger means being responsive to the occurrence of said second actuating signal for causing said output signal to switch to its first signal level.
Claim 8
Dependent Claim
62 words
A fuel control as in cliam 6 and further including means for sensing the magnitude of said first and second ramp voltage signals, and means for causing said output signal to switch from one to the other of said first and second signal levels when the magnitude of either of said first and second ramp voltage signals exceeds a predetermined voltage level.
Claim 9
Dependent Claim
62 words
A fuel control as in cliam 6 and further including means for sensing the magnitude of said first and second ramp voltage signals, and means for causing said output signal to switch from one to the other of said first and second signal levels when the magnitude of either of said first and second ramp voltage signals exceeds a predetermined voltage level.
Claim 10
Dependent Claim
42 words
A fuel control as in claim 7 and including means for inhibiting said first integrator when said output signal is at said second signal level, and means for inhibiting said second integrator when said output signal is at said first signal level.
References Cited (Backward Citations)
US3432356A
Cited
US3389018A
Cited
US3343991A
Cited
US3585078A
Cited
US3600229A
Cited
US3697325A
Cited
US3745047A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |