US4023442A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic control means for infinitely variable transmission
Assignee: Oklahoma State University
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Filing: 1975-07-07
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Granted: 1977-05-17
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Expires: 1995-07-07
Abstract
Abstract This invention describes a system of control for a power source-transmission-load system such as might be used on an off-the-road vehicle, for example. The power source is an internal combustion engine having a known optimum characteristic of desired manifold vacuum versus engine speed. The transmission is a hydrostatic or hydromechanical transmission having infinitely variable speed ratio and having a control means for varying said speed ratio. The control system includes a transducer means for measuring engine speed and converting this quantity into an analog fluid pressure proportional to the speed. This analog fluid pressure proportional to speed is modified in a function generator to produce an analog fluid pressure which is proportional to the desired manifold vacuum as a function of engine speed. Means are provided for measuring the actual manifold vacuum and for comparing the actual manifold vacuum with the desired manifold vacuum on a continuous basis. This comparison produces an error signal which is amplified and used to control a hydraulic system to operate the control means in order to vary the transmission ratio of the hydrostatic or hydromechanical transmission to obtain a speed ratio such that will provide optimum engine conditions.
Inventors
- 👤 Robert L. Woods
- 👤 Karl N. Reid, Jr.
- 👤 Rajamouli Gunda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:47
CPC Classifications
B; B60; B60W; B60W10/00; B60W10/04; B60W10/06; B60W10/10; B60W10/101; B60W10/103; B60W30/00; B60W30/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
168 words
In a power source-variable speed-transmission-load system in which said power source is an internal combustion engine having a known characteristic of desired manifold vacuum vs. engine speed, said transmission is an infinitely variable transmission having infinitely variable speed ratio, and having a control means for varying said speed ratio, the improvement in automatic control systems for operating said engine at the proper speed for each load to obtain optimum system efficiency, comprising: a. transducer means to measure engine speed and generate a speed signal; b. function generator means responsive to said transducer means to convert said speed signal to a signal which is a function of desired manifold vacuum; c. means to measure actual manifold vacuum; d. means to compare said desired with said actual manifold vacuum to obtain an error signal; e. means to amplify said error signal; and f. means responsive to said amplified error signal to operate said control means on said infinitely variable transmission to vary said speed ratio to reduce said error signal.
Claim 2
Dependent Claim
168 words
In a power source-variable speed-transmission-load system in which said power source is an internal combustion engine having a known characteristic of desired manifold vacuum vs. engine speed, said transmission is an infinitely variable transmission having infinitely variable speed ratio, and having a control means for varying said speed ratio, the improvement in automatic control systems for operating said engine at the proper speed for each load to obtain optimum system efficiency, comprising: a. transducer means to measure engine speed and generate a speed signal; b. function generator means responsive to said transducer means to convert said speed signal to a signal which is a function of desired manifold vacuum; c. means to measure actual manifold vacuum; d. means to compare said desired with said actual manifold vacuum to obtain an error signal; e. means to amplify said error signal; and f. means responsive to said amplified error signal to operate said control means on said infinitely variable transmission to vary said speed ratio to reduce said error signal.
Claim 3
Dependent Claim
33 words
The system as in claim 1 in which said function generator operates on a curve of desired engine vacuum vs. engine speed the curve being preselected considering the efficiency of the engine alone.
Claim 4
Dependent Claim
38 words
The system as in claim 1 in which said function generator operates on a curve of desired engine vacuum vs. engine speed the curve being preselected considering the efficiency of the combination of the engine plus the transmission.
Claim 5
Dependent Claim
15 words
The system as in claim 1 in which said control system comprises a fluidic-hydraulic system.
Claim 6
Dependent Claim
15 words
The system as in claim 4 in which said fluidic system is a pneumatic system.
Claim 7
Dependent Claim
178 words
In a power source-variable speed-transmission-load system in which said power source is an internal combustion engine having a known characteristic of desired manifold vacuum vs. engine speed, said transmission is an infinitely variable transmission having infinitely variable speed ratio, and having a control means for varying said speed ratio, the improvement in automatic control systems for operating said engine at the proper speed for each load to obtain optimum system efficiency, comprising: a. transducer means to measure engine speed and convert said engine speed to a fluid pressure speed signal proportional to said speed; b. function generator means responsive to said transducer means to convert said fluid pressure speed signal to a fluid pressure proportional to desired manifold vacuum; c. means to measure actual manifold vacuum; d. means to compare said desired with said actual manifold vacuum to obtain an error signal; e. means to amplify said error signal; and f. means responsive to said amplified error signal to operate said control means on said infinitely variable transmission to vary said speed ratio to reduce said error signal.
Claim 8
Dependent Claim
178 words
In a power source-variable speed-transmission-load system in which said power source is an internal combustion engine having a known characteristic of desired manifold vacuum vs. engine speed, said transmission is an infinitely variable transmission having infinitely variable speed ratio, and having a control means for varying said speed ratio, the improvement in automatic control systems for operating said engine at the proper speed for each load to obtain optimum system efficiency, comprising: a. transducer means to measure engine speed and convert said engine speed to a fluid pressure speed signal proportional to said speed; b. function generator means responsive to said transducer means to convert said fluid pressure speed signal to a fluid pressure proportional to desired manifold vacuum; c. means to measure actual manifold vacuum; d. means to compare said desired with said actual manifold vacuum to obtain an error signal; e. means to amplify said error signal; and f. means responsive to said amplified error signal to operate said control means on said infinitely variable transmission to vary said speed ratio to reduce said error signal.
Claim 9
Dependent Claim
19 words
The system as in claim 6 in which said transmission is a hydrostatic transmission having infinitely variable speed ratio.
Claim 10
Dependent Claim
42 words
The system as in claim 6 in which said transducer means includes notched disc means driven proportional to engine speed, two fluid nozzles, and means to convert the pulsations of pressure in said nozzles to an analog fluid pressure proportional to speed.
References Cited (Backward Citations)
US3121483A
Cited
US3360069A
Cited
US3741042A
Cited
US3738197A
Cited
US3855793A
Cited
US3932991A
Cited
US3927528A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |