EP0512596A1
Expired / Lapsed
EP
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A method of shift pattern control for a motor vehicle automatic transmission
Assignee: Delco Electronics LLC
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Filing: 1992-04-15
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Granted: —
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Expires: 2012-04-15
Abstract
Abstract A shift pattern control in which upshifting and downshifting is modified in response to a detected condition of above normal road load. The above normal loading may be due to a number of conditions such as trailering, steep grades, unusual aerodynamic loading, or any combination thereof. A load equation balancing the output torque of the engine at the output of the transmission against the nominal road load (including acceleration torque, aerodynamic torque and rolling resistance torque) provides a continuous indication of the excess or above normal road load. The excess load, referred to herein as the grade load GL, is used to develop a hysteresis term for modifying the base shift pattern so as to provide earlier downshifting and later upshifting. When the grade load exceeds a reference corresponding to a relatively high load condition, upshifting is further delayed in relation to the ability of the powertrain to overcome the detected road load in the upshifted speed ratio.
Inventors
- 👤 Larry Theodore Nitz
- 👤 Michael Robert Witkowski
- 👤 William Joseph Bolander
- 👤 Rimas Stasys Milunas
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 04:02
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0202; F16H61/0204; F16H61/0213; F16H59/00; F16H59/14; F16H59/60; F16H59/66; F16H61/68; F16H61/682
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
173 words
A method of operation in a motor vehicle including an engine (12) connected to a drive axle (20,22) through a transmission (14) having multiple speed ratios, the method comprising the steps of initiating upshifting or 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 axle torque value corresponding to a drive axle torque developed at the drive axle by the engine and transmission during nonshifting modes of operation; and determining a nominal road load torque which must be overcome by the drive axle torque with normal vehicle loading; characterised by developing an indication of above normal loading in relation to an amount by which the axle torque value exceeds the nominal road load torque; and modifying the measured load condition parameters by an offset amount in relation to the indication of above normal loading so as to provide earlier initiation of downshifting and later initiation of upshifting, as compared to the base shift pattern.
Claim 2
Dependent Claim
25 words
A method as claimed in Claim 1, including the step of inhibiting the modification of the measured load condition parameter if the vehicle is accelerating.
Claim 3
Dependent Claim
32 words
A method as claimed in Claim 1, including the step of inhibiting the modification of the measured load condition parameter if the vehicle speed is not decreasing despite the above normal loading.
Claim 4
Independent Claim
154 words
A method of operation in a motor vehicle including an engine (12) connected to a drive axle (20,22) through a transmission (14) having multiple speed ratio, the method comprising the steps of determining an axle torque value corresponding to a drive axle torque developed at the drive axle by the engine and transmission during nonshifting modes of operation; and determining a nominal road load torque which must be overcome by the drive axle torque with normal vehicle loading; characterised by developing an indication of above normal loading in relation to an amount by which the axle torque value exceeds the nominal road load torque; and initiating upshifting or downshifting between the speed ratios when a comparison of measured load condition parameters, modified by an offset amount determined in relation to the indication of above normal loading, with predetermined load condition parameters defined by a shift pattern indicates that such upshifting and downshifting is desired.
Claim 5
Dependent Claim
72 words
A method as claimed in Claim 4, wherein the step of initiating upshifting and downshifting includes the steps of measuring first and second vehicle parameters; modifying the first vehicle parameter by the offset amount; applying the modified vehicle parameter to the shift pattern to obtain a shift pattern parameter which must be achieved to initiate a shift; and initiating the shift when the second vehicle parameter substantially equals the shift pattern parameter.
Claim 6
Dependent Claim
30 words
A method as claimed in Claim 5, wherein the first vehicle parameter is a throttle position of the engine, and the second vehicle parameter is a speed of the vehicle.
Claim 7
Independent Claim
182 words
A method of operation in a motor vehicle including an engine (12) connected to a drive axle (20,22) through a transmission (14) having multiple speed ratios, the method comprising the steps of initiating a shift to a different speed ratio in response to a comparison of measured load condition parameters with predetermined load condition parameters defined by a base shift pattern; determining an axle torque value corresponding to a drive axle torque developed at the drive axle by the engine and transmission during nonshifting modes of operation; and determining a nominal road load torque which must be overcome by the drive axle torque with normal vehicle loading; characterised by developing an indication of above normal loading in relation to an amount by which the axle torque value exceeds the nominal road load torque; determining an offset amount in relation to the indication of above normal loading; and increasing the measured load condition parameters by the offset amount, thereby to compensate for the above normal loading by initiating shifting based on a perceived load condition which is higher than the measured load condition.
Claim 8
Dependent Claim
81 words
A method as claimed in Claim 7, wherein the step of determining an offset amount in relation to the indication of above normal loading includes the steps of computing an offset value in relation to the indication of above normal loading; updating the offset amount to track both increases and decreases in the computed offset value if the vehicle is decelerating; and updating the offset amount to track only decreases in the computed offset value if the vehicle is not decelerating.
Claim 9
Independent Claim
237 words
A method of operation in a motor vehicle including an engine (12) connected to a drive axle (20,22) through a transmission (14) having multiple speed ratios, the method comprising the steps of initiating an upshift from a lower speed range to an upper speed range in response to a comparison of measured load condition parameters with predetermined load condition parameters defined by a base shift pattern; determining an axle torque value corresponding to a drive axle torque developed at the drive axle by the engine and transmission in the lower speed range; determining a nominal road load torque which must be overcome by the drive axle torque with normal vehicle loading; developing a measure of above normal loading in relation to an amount by which the axle torque value exceeds the nominal road load torque; and developing an indication of the axle torque which can be developed at said drive axle in the upper speed range relative to the axle torque value if substantial above normal loading is measured; characterised by modifying the measured load condition parameters by an offset amount determined in relation to the measure of above normal loading so as to provide later initiation of upshifting to the upper speed range than would occur without such modification if the indication exceeds a threshold value; and inhibiting the initiation of upshifting to the upper speed range if the indication is less than the threshold value.
Claim 10
Dependent Claim
22 words
A method as claimed in Claim 9, wherein the threshold value is determined in relation to the measure of above normal loading.
References Cited (Backward Citations)
US4354236A
Cited
EP0139982A1
Cited
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