Patent US4790145A successfully refreshed from Google Patents.
US4790145A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superheat control of air conditioning system incorporating fuel cooler
Assignee: MID-AMERICA COMMERCIALIZATON Corp
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Filing: 1987-11-13
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Granted: 1988-12-13
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Expires: 2007-11-13
Abstract
Abstract A system for preventing vapor-lock in a positively pressurized loop-type engine fuel line having the low pressure or tank return portion of the fuel line passing through a heat exchanger disposed in the refrigerant line for the vehicle air conditioner between the endothermic heat exchanger or evaporator and the compressor inlet. A thermistor senses the temperature of the refrigerant discharging from the fuel line heat exchanger and a pressure transducer senses evaporator discharge saturation pressure. Look-up tables are used to determine saturation temperature from the saturation pressure, and saturation temperature and actual refrigerant temperature compared to generate a pulse-width modulated control signal for controlling an electrically operated refrigerant expansion valve to maintain a desired amount of superheat at the discharge of the fuel line heat exchanger.
Inventors
- 👤 Michael B. Thompson
- 👤 Robert J. Torrence
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:44
CPC Classifications
F; F25; F25B; F25B5/00; F02; F02M; F02M31/00; F02M31/20; F02M37/00; F02M37/20; F25B41/00; F25B41/30; F25B41/31; F25B41/34; F25B41/345; F25B41/347; F25B2341/00; F25B2341/06; F25B2341/068; F25B2341/0683; Y; Y02; Y02B; Y02B30/00; Y02B30/70; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
239 words
A system for controlling vapor lock in an engine fuel line comprising: (a) a first and a second endothermic heat exchanger serially connected, said first exchanger disposed for cooling a compartment and said second exchanger in heat exchange relationship with said fuel line; (b) an exothermic heat exchanger; (c) electrically operated expansion valve means; (d) refrigerant conduit means connecting said expansion valve means intermediate said exothermic heat exchanger and first endothermic heat exchanger: (e) compressor means operative upon energization to circulate refrigerant through said exothermic heat exchanger through said expansion valve means and through said first and second endothermic heat exchangers; (f) pressure sensing means disposed to sense the pressure of refrigerant flow between said first and second endothermic heat exchangers and provide an electrical signal indicative of said pressure; (g) temperature sensing means disposed in a conduit means between said second endothermic heat exchanger and said compressor means and operative to provide an electrical signal T A indicative of the temperature of refrigerant flow in said conduit means; (h) means to convert said sensed pressure to saturation temperature, Ts, for the refrigerant being circulated; and (i) comparator means operable to compare T A and T S and generate a control signal indicative of said comparison and means for operating said expansion valve means responsive to said control signal; and; (j) means operative to circulate engine fuel through said second endothermic heat exchanger for heat exchange with said refrigerant.
Claim 2
Independent Claim
239 words
A system for controlling vapor lock in an engine fuel line comprising: (a) a first and a second endothermic heat exchanger serially connected, said first exchanger disposed for cooling a compartment and said second exchanger in heat exchange relationship with said fuel line; (b) an exothermic heat exchanger; (c) electrically operated expansion valve means; (d) refrigerant conduit means connecting said expansion valve means intermediate said exothermic heat exchanger and first endothermic heat exchanger: (e) compressor means operative upon energization to circulate refrigerant through said exothermic heat exchanger through said expansion valve means and through said first and second endothermic heat exchangers; (f) pressure sensing means disposed to sense the pressure of refrigerant flow between said first and second endothermic heat exchangers and provide an electrical signal indicative of said pressure; (g) temperature sensing means disposed in a conduit means between said second endothermic heat exchanger and said compressor means and operative to provide an electrical signal T A indicative of the temperature of refrigerant flow in said conduit means; (h) means to convert said sensed pressure to saturation temperature, Ts, for the refrigerant being circulated; and (i) comparator means operable to compare T A and T S and generate a control signal indicative of said comparison and means for operating said expansion valve means responsive to said control signal; and; (j) means operative to circulate engine fuel through said second endothermic heat exchanger for heat exchange with said refrigerant.
Claim 3
Dependent Claim
30 words
The system defined in claim 1, wherein said control signal comprises a width modulated pulse for opening said expansion valve means at varying fractions of the period of said pulse.
Claim 4
Dependent Claim
27 words
The system defined in claim 1, wherein said control signal comprises a width modulated pulse having initially a width comprising 40% of the period of said pulse.
Claim 5
Dependent Claim
57 words
The control system defined in claim 1, further comprising: (a) a fuel temperature sensor disposed in said fuel line and operative to emit an electrical signal indicative of said fuel line temperature; and (b) means receiving said fuel temperature signal and operative to energize said compressor means when said fuel line temperature rises to a predetermined level.
Claim 6
Dependent Claim
54 words
The control system defined in claim 1, further comprising a thermistor disposed in said fuel line and means operative to sense the change in resistance of said thermistor in response to changes in fuel line temperature; and, means responsive to sensing a predetermined level of said thermistor resistance operative to energize said compressor means.
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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) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |