Patent EP0559263A1 successfully refreshed from Google Patents.
EP0559263A1
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EP
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A method of operating an automatic transmission
Assignee: Saturn Corp
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Filing: 1993-02-16
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Granted: —
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Expires: 2013-02-16
Abstract
Abstract An improved shift pattern control in which successive upshifting and downshifting is avoided in conditions of above normal loading by inhibiting upshifting to a speed ratio having insufficient gradeability in relation to a measure of the actual loading. In essence, the control continually monitors the gradeability of the various forward speed ratios of the automatic transmission in relation to a measure of the actual grade load to determine their excess gradeability, and removes from the shift pattern those speed ratios having insufficient excess gradeability. This ensures that the automatic transmission will never be upshifted to a speed ratio that has insufficient gradeability for the given driving condition, thereby eliminating the successive upshifting and downshifting which occurs with conventional shift controls.
Inventors
- 👤 Larry Theodore Nitz
- 👤 Susan Lettie Rees
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 03:49
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/16; F16H61/02; F16H61/0202; F16H61/0204; F16H61/0213; F16H61/0206; F16H2061/0209; F16H2061/161; F16H59/00; F16H59/50; F16H59/52; F16H59/60; F16H59/62; F16H59/66; F16H61/21; F16H61/68; F16H61/682; Y; Y10; Y10S; Y10S477/00; Y10S477/90
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
171 words
A method of operation in a motor vehicle including an engine (12) and an automatic transmission (14) providing a plurality of forward speed ratios through which the engine may drive the motor vehicle, the method comprising the steps of initiating upshifting and downshifting between the speed ratios in response to a comparison of measured load condition parameters with predetermined load condition parameters defined by a base shift pattern; determining an apparent grade load indication in relation to an imbalance between engine produced torque and an estimate of the torque required to achieve a current driving condition of the motor vehicle; determining maximum gradeability indications corresponding to a maximum grade load which can be overcome with the forward speed ratios; comparing the apparent grade load with the maximum gradeability indications to form an indication of excess gradeability of each such speed ratio; and overriding the base shift pattern when an excess gradeability indication for a respective speed ratio is less than a reference value by inhibiting upshifting to such respective speed ratio.
Claim 2
Dependent Claim
61 words
A method as claimed in Claim 1, including the step of increasing a maximum gradeability indication for a given speed ratio in relation to an estimate of a transmission input speed which would occur in a successively lower speed ratio, so as to prevent overriding of the base shift pattern which would produce undesirably high input speed during engine braking conditions.
Claim 3
Dependent Claim
59 words
A method as claimed in Claim 1 or Claim 2, wherein the step of determining maximum gradeability indications includes the steps of retrieving predetermined gradeability values corresponding to the maximum gradeability of the forward speed ratios at sea level; and adjusting the gradeability values in relation to an indication of ambient barometric pressure to form the maximum gradeability indications.
Claim 4
Dependent Claim
177 words
Control apparatus for a motor vehicle including an engine (12) and an automatic transmission (14) providing a plurality of forward speed ratios through which the engine may drive the motor vehicle, the control apparatus comprising means for initiating upshifting and downshifting between the speed ratios in response to a comparison of measured load condition parameters with predetermined load condition parameters defined by a base shift pattern; means for determining an apparent grade load indication in relation to an imbalance between engine produced torque and an estimate of the torque required to achieve a current driving condition of the motor vehicle; means for determining maximum gradeability indications corresponding to a maximum grade load which can be overcome with the forward speed ratios; means for comparing the apparent grade load with the maximum gradeability indications to form an indication of excess gradeability of each such speed ratio; and means for overriding the base shift pattern when an excess gradeability indication for a respective speed ratio is less than a reference value by inhibiting upshifting to such respective speed ratio.
Claim 5
Dependent Claim
29 words
Control apparatus as claimed in Claim 4, comprising a range selector positionable by a vehicle driver to exclude at least one specified speed ratio from the base shift pattern.
References Cited (Backward Citations)
US4335428A
Cited
GB2052651A
Cited
EP0312276A1
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WO1989003319A1
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EP0512596A1
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EP0532957A2
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