Adaptive control system for automatic transmission

• US 3,956,947 A
• Filed: 06/14/1974
• Issued: 05/18/1976
• Est. Priority Date: 06/14/1974
• Status: Expired due to Term

• Current Assignee: Chrysler Corporation (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Bradley, Robert Leslie, Leising, Maurice Bernard, Benford, Howard Lee
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): Chandler, Lance W.
• Application Number:
  US05/479,320
• Time in Patent Office: 704 Days
• Field of Search: 74/866, 74/867, 74/868, 74/869, 74/844, 74/752 A, 192/103 C
• US Class Current: 477/120
• CPC Class Codes: F16H 2059/425 Rate of change of input or turbine shaft speed
• CPC Class Codes: F16H 2059/6807 Status of gear-change operation, e.g. clutch fully engaged
• CPC Class Codes: F16H 2061/0466 Smoothing shift shock by apply or release of band brake servos, e.g. overlap control of band brake and a clutch or vice versa
• CPC Class Codes: F16H 59/38 of gearing elements
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: Y10S 477/904 Control signal is acceleration

Abstract

A control system for an automatic transmission of the type having an input shaft assembly, an output shaft assembly, a plurality of power transmitting gear assemblies connecting the input shaft assembly and output shaft assembly and adapted to be coupled to provide various ratios between input and output shaft assembly rotation, engaging devices for effecting changes in the ratios provided by the power transmitting gear assemblies, and servos for operating the engaging devices. Pressure regulating devices are provided for controlling the application of pressurized fluid to the servo means, and control apparatus is provided which is responsive to the rate of change of rotational speed, i.e., acceleration, of at least one of the rotatable components of the assemblies to control the output torque of the transmission during a shift from one ratio to another.

Claims

1. In a control system for an automatic transmission of the type having a housing, an input shaft assembly, an output shaft, a plurality of power transmitting gear assemblies connecting said input shaft assembly and output shaft and adapted to be coupled to provide various ratios between input assembly and output shaft rotation, engaging and disengaging devices for effecting changes in the ratios provided by said power transmitting gear assemblies, and servo means for operating said engaging and disengaging devices, the improvement comprising control means for controlling the application and release of said servo means, means for controlling the operation of said control means to cause said servos to operate in response to the rotational acceleration of at least one of the rotatable components of said assemblies to cause a curve of rotational speed versus time of one of said components to follow substantially along a predetermined path during a shift from one ratio to another, said means responsive to rotational acceleration including means for sensing a rotational characteristic of said one rotatable component, and means connected to said speed sensing means for maintaining said one rotatable component in a substantially incipient slip condition relative to said housing during a portion of a shift from one ratio to another ratio, said one rotatable component, when maintained in said substantially incipient slip condition, alternately and repeatedly being allowed to slip in a rearward direction and then being brought to a substantially zero rotational velocity along a generally undular velocity versus time curve during said portion of said shift.

2. In a control system as set forth in claim 1, wherein said means for causing a curve of the rotational velocity of said one rotatable component versus time to be undular as it is maintained in said incipient slip condition during said portion of a shift from one ratio to another also cause said one rotatable component to follow substantially along a predetermined undular path during another portion of the shift from said one ratio to said second mentioned ratio.

3. In an engine driven vehicle having a throttle valve control, a multispeed power transmission unit comprising input and output shafts, gearing interconnecting said shafts and arranged for selective activation to provide for transmission of a first, a second and third speed drive between said shafts, and automatically operable vehicle speed and throttle valve responsive pressure fluid activatable control means for said gearing arranged to automatically provide for sequential upshifts from first to second to third speed drive and reversely arranged downshifts, said automatically operable transmission shift control means including a first friction coupling device adapted to be engaged when the transmission is in a third speed drive condition and disengaged when said transmission is in a second speed condition, first and second members adapted to be coupled together when said first friction coupling device is engaged, a second friction coupling device for braking said first member, means for applying said second friction coupling device to said first member, said second friction coupling device being applied to said first member when said transmission is in a second speed condition and being in a nonapplied condition relative to said first member when said transmission is in a third speed condition, said means for applying said second friction coupling device including means for causing said second friction coupling device to move said first member from a rotating condition in first speed drive condition to a substantially zero rotational condition in second speed drive condition in a predetermined time along a predetermined velocity curve, and means deactuating said means for applying said second friction coupling device and for actuating said first friction coupling device to cause a curve of the velocity of said first member versus time during a shift from a second speed drive condition to a third speed drive condition to be generally undular, said second friction coupling device keeping said first member in a substantially incipient slip condition for a period, and then releasing said first member while said first friction coupling device is being actuated to rotate said first member, said curve remaining undular when said first member is in said incipient slip condition as well as when rotated by said first friction coupling said first member, when kept in said substantially incipient slip condition and following said generally undular velocity versus time curve, alternately and repeatedly being allowed to slip slightly in a rearward direction, and then being brought to a substantially zero rotational velocity.

4. In an engine driven vehicle having a throttle valve control, a multispeed power transmission unit comprising input and output shafts, gearing interconnecting said shafts and arranged for selective activation to provide for transmission of a first, a second and third speed drive between said shafts, and automatically operable vehicle speed and throttle valve responsive pressure fluid activatable control means for said gearing arranged to automatically provide for sequential upshifts from first to second to third speed drive and reversely arranged downshifts, said automatically operable transmission shift control means including a first friction device adapted to be engaged when said transmission is in a third speed drive condition and disengaged when said transmission is in a second speed condition, friction device actuating means for actuating said first friction device, first and second members adapted to be coupled together when said first friction device is engaged, a second friction device for braking said first member, a servo means for applying said second friction device, said second friction device being applied when said transmission is in a second speed condition and being in a nonapplied condition relative to said first member when said transmission is in a third speed condition, said shift control means including means for causing a curve of velocity versus time for said first member during shifts between said first, second, and third speed drive conditions to follow substantially along a predetermined generally undular path to control the torque output of the transmission, servo means being fluid pressure operated, means for causing said velocity versus time curve to follow said predetermined path including means for electrically causing the intermittent interruption and establishment of the supply of fluid to said servo means for causing said velocity-time curve for said first member to follow said predetermined path during a shift from a first speed drive condition to a second speed drive condition, said friction device actuating means being fluid pressure operated, said means for causing said velocity versus time curve to follow said predetermined path including means for electrically causing the intermittent interruption and establishment of the supply of fluid to said friction device actuating means for causing said velocity-time curve for said member to follow said predetermined undular path during a shift from a second speed drive condition to a third speed drive condition said means for causing said velocity versus time curve to follow said predetermined undular path during a shift from a second speed drive condition to a third speed drive condition including means for maintaining said one member in an incipient slip condition during a portion of the shift, said means for electrically causing the intermittent interruption and establishment of the supply of fluid to said friction device actuating means causing said velocity-time curve for said first member to follow said predetermined undular path during a shift from a third speed drive condition to a second speed drive condition said first member being held in alternating incipient forward rotation and incipient rearward slip conditions during a portion of the shift from a third speed drive condition to a second speed drive condition, said second friction device being maintained in an unapplied condition during a shift from third speed condition to a second speed condition until said first member is brought to said alternating incipient forward rotation and incipient rearward slip conditions, and then being applied to hold said first member against rotation, whereby a significant reduction in the output torque of the transmission is avoided.

5. In a control system for an automatic transmission of the type having a housing, an input shaft assembly, an output shaft, a plurality of power transmitting gear assemblies connecting said input shaft assembly and output shaft and adapted to be coupled to provide various ratios between input assembly and output shafts rotation, engaging and disengaging devices for effecting changes in the ratios provided by said power transmitting gear assemblies, and servo means for operating said engaging and disengaging devices, the improvement comprising control means for controlling the application and release of said servo means, means for controlling the operation of said control means to cause said servos to operate in response to the rotational acceleration of at least one of the rotatable components of said assemblies to cause a curve of rotational speed versus time of one of said components to follow substantially along a predetermined path during a shift from one ratio to another, said means responsive to the rotational acceleration including means for causing a curve of the rotational velocity of one rotatable component versus time to be generally undular during a shift from one ratio to another, said servo means being fluid pressure operated, control means comprising valves adapted to be moved between a first position wherein communication is established between fluid under pressure and said servo means and a second position wherein communication between said servo means and said fluid under pressure is blocked and communication between said servo means and fluid at a pressure lower than in said servo means is established, said means responsive to the rotational acceleration of at least one of the rototable components of said assemblies including electrically operated means adapted to actuate said valves between their first and second positions, and means for signalling said electrically operated means that said one rotatable component has reached a predetermined rotational acceleration, said means responsive to the rotational acceleration further including means for maintaining the rotatable component having a speed curve which follows along said undular path in a substantially incipient slip condition relative to said housing during a portion of a shift from one ratio to another, the speed curve also being undular when the rotatable component is maintained in said substantially incipient slip condition and said rotatable component, when maintained in said substantially incipient slip condition, alternately and repeatedly being allowed to slip slightly in a rearward direction and then being brought to a substantially zero rotational velocity.