US5218836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Measuring evaporator load in an automotive air conditioning system for compressor clutch control using evaporator inlet temperature
Assignee: Eaton Corp
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Filing: 1992-06-11
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Granted: 1993-06-15
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Expires: 2012-06-11
Abstract
Abstract An electronic controller receives an evaporator inlet (or outlet) temperature sensor signal and measures the time required for the evaporator to be heated from compressor clutch cut-out to compressor clutch "ON". Depending upon the elapsed time, the controller selects from a predetermined schedule, a new value CLHOFF of the evaporator inlet temperature at which the compressor is next cut-out, raising CLHOFF for lighter thermal loading to prevent evaporator icing and freeze-up and lowering CLHOFF for heavy thermal loading to prevent unwanted compressor cycling.
Inventors
- 👤 George W. Jarosch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:20
CPC Classifications
B; B60; B60H; B60H1/00; B60H1/32; B60H1/3204; B60H1/3205; B60H1/321; F; F25; F25B; F25B47/00; F25B47/006; B60H2001/3236; B60H2001/3255; B60H2001/3263; B60H2001/3269; B60H2001/327; F25B2600/00; F25B2600/02; F25B2600/025; F25B2600/0251
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
108 words
A method of controlling refrigerant flow in a refrigerant system of the type having an energizable and de-energizable pump for circulating refrigerant through a condenser, an expression valve, an evaporator and return to the pump comprising: (a) sensing the temperature T b at of one the evaporator inlet and the evaporator outlet; (b) de-energizing said pump when T b falls below a first predetermined level CLHOFF and energizing said pump when T b rises above a second predetermined level CLHON; (c) counting the time RCOUNT elapsed from when T b rises from CLHOFF to CLHON and varying CLHOFF in accordance with a predetermined schedule of change in RCOUNT.
Claim 2
Independent Claim
108 words
A method of controlling refrigerant flow in a refrigerant system of the type having an energizable and de-energizable pump for circulating refrigerant through a condenser, an expression valve, an evaporator and return to the pump comprising: (a) sensing the temperature T b at of one the evaporator inlet and the evaporator outlet; (b) de-energizing said pump when T b falls below a first predetermined level CLHOFF and energizing said pump when T b rises above a second predetermined level CLHON; (c) counting the time RCOUNT elapsed from when T b rises from CLHOFF to CLHON and varying CLHOFF in accordance with a predetermined schedule of change in RCOUNT.
Claim 3
Dependent Claim
17 words
The method defined in claim 1, further comprising: delaying a predetermined time interval and repeating steps (a)-(c).
Claim 4
Dependent Claim
26 words
The method defined in claim 1, wherein said step of varying comprises decrementing CLHOFF by 1.5° F. for each 3 seconds of change in said RCOUNT.
References Cited (Backward Citations)
US4856293A
Cited
US5117646A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |