EP0435377A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of controlling gear change in an automatic transmission
Assignee: Motors Liquidation Co
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Filing: 1990-12-13
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Granted: —
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Expires: 2010-12-13
Abstract
Abstract In an automatic transmission 16, clutch-to-clutch closed throttle downshifting is controlled by filling the on-coming clutch C1-C5 at a maximum pressure command for a set period while commanding the off-going clutch pressure to a low value and exhausting the off-going clutch C1-C5 before the end of the fill period. At the end of the fill period the on-coming pressure is set to an initial value and then ramped up until turbine speed Nt is pulled up due to off-going clutch slippage. Then a closed-loop profile control period starts wherein the slip of the on-coming clutch C1-C5 is measured and controlled to a slip profile. When synchronization of the on-coming clutch is detected, maximum pressure is commanded. Parameters for controlling the quality of a shift such as on-coming clutch initial pressure and on-coming clutch fill time are automatically adjustable during vehicle use to correct shift aberrations which degrade shift quality.
Inventors
- 👤 Jeffrey Kurt Runde
- 👤 Joseph Henry Hunter
- 👤 John Anthony Hibner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 05:08
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/04; F16H61/06; F16H61/061; F16H59/00; F16H59/36; F16H59/38; F16H2059/385; F16H59/68; F16H2059/6807; F16H2061/0075; F16H2061/0078; F16H2061/0087; F16H2061/0477
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
244 words
A method of controlling the change in an automatic transmission of a vehicle from an off-going fluid pressure operated torque transmitting device (C1-C5) associated with a lower speed ratio to an on-coming fluid pressure operated torque transmitting device (C1-C5) associated with a higher speed ratio when the engine throttle is substantially closed, wherein the off-going torque transmitting device is disengaged substantially concurrently with the engagement of the on-coming torque transmitting device, the transmission including an input (22), an output (24), a turbine (14) connected to the input to couple driving torque thereto, and turbine speed (Nt) and output speed (No) sensing means; the method comprising the steps of disengaging the off-going torque transmitting device by reducing its pre-change operating pressure on the basis of a predefined disengagement procedure; engaging the on-coming torque transmitting device by applying on-coming pressure for a predefined fill period, setting the on-coming pressure to an initial on-coming pressure and subsequently controlling the on-coming pressure in a period of closed-loop control to effect progressive engagement of the on-coming torque transmitting device; detecting the occurrence of an increase in on-coming pressure above a predetermined value during the period of the closed-loop control; and, on the basis of the detection, adjusting a first stored parameter related to the value of the initial on-coming pressure so as to increase the initial on-coming pressure, or adjusting a second stored parameter related to the length of the fill period so as to increase the fill period.
Claim 2
Dependent Claim
29 words
A method according to Claim 1, wherein the first parameter is adjusted when the increase in on-coming pressure during the period of closed-loop control is above the predetermined value.
Claim 3
Dependent Claim
26 words
A method according to Claim 2, wherein the first parameter is adjusted when the period of closed-loop control is longer than a predetermined length of time.
Claim 4
Dependent Claim
35 words
A method according to Claim 1, 2 or 3, wherein the second stored parameter is increased when the increase in on-coming pressure during the period of the closed-loop control is less than the predetermined value.
Claim 5
Independent Claim
28 words
A method according to any preceding Claim, wherein the second stored parameter is adjusted when the period of closed-loop control is shorter than a predetermined length of time.
Claim 6
Independent Claim
57 words
A method according to any preceding Claim, including the steps of detecting slip of the off-going torque transmitting device and substantial synchronization of the on-coming torque transmitting device, measuring the time between the detected slip and the detected synchronization, and inhibiting adjustment of the first stored parameter when the measured period is less than a preset amount.
Claim 7
Independent Claim
30 words
A method according to any preceding Claim, including the steps of measuring turbine acceleration, and inhibiting adjustment of the first stored parameter when the acceleration is above a preset value.
Claim 8
Independent Claim
75 words
A method according to any preceding Claim, wherein the step of adjusting the first stored parameter comprises the step of adjusting the first stored parameter by a relatively larger amount prior to the occurrence of a non-aberrant change, and by a relatively smaller amount after the occurrence of a non-aberrant change, wherein a non-aberrant change is determined by the occurrence of a change in which no adjustment of the first or second parameters is made.
Claim 9
Independent Claim
33 words
A method according to any preceding Claim, including the steps of measuring turbine deceleration, and inhibiting adjustment of the first and second stored parameters when the deceleration is greater than a preset value.
Claim 10
Independent Claim
30 words
A method according to any preceding Claim, comprising the step of detecting whether the on-coming pressure is below a pressure required to provide engagement of the on-coming torque transmitting device.
Claim 11
Dependent Claim
69 words
A method according to Claim 10, wherein the step of determing whether the on-coming pressure is below the required pressure comprises the step of detecting failure of slip of the on-coming torque transmitting device on the basis of turbine speed and output speed, wherein slip is determined to have occurred when turbine speed is increased above the turbine speed at the corresponding output speed at the higher speed ratio.
Claim 12
Dependent Claim
59 words
A method according to Claim 10 or 11, wherein the step of determining whether the on-coming pressure is below the required pressure comprises the step of detecting underlap after the fill time, wherein underlap is determined to have occurred by a decrease in turbine speed below the turbine speed corresponding to the output speed at the higher speed ratio.
Claim 13
Dependent Claim
43 words
A method according to Claim 10, 11 or 12, wherein the step of determining whether the on-coming pressure is below the required pressure comprises the step of detecting the occurrence of flare after a predetermined time after the end of the fill period.
Claim 14
Dependent Claim
78 words
A method according to Claim 10, including the steps of detecting whether the on-coming pressure is above a predetermined pressure by sensing the occurrence of speed aberrations; reducing the on-coming pressure on sensing speed aberrations by adjusting the second stored parameter so as to reduce the fill period; and, on a subsequent change when the on-coming pressure is determined to be below the required pressure, adjusting the first stored parameter if the fill period has previously been reduced.
References Cited (Backward Citations)
No citation records indexed.
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