Automatic transmission line pressure control

• US 4,283,970 A
• Filed: 07/02/1979
• Issued: 08/18/1981
• Est. Priority Date: 07/02/1979
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Vukovich, William J.
• Primary Examiner(s): Braun, Leslie
• Application Number:
  US06/053,781
• Time in Patent Office: 778 Days
• Field of Search: 74/866, 74/752 D, 74/861, 74/862
• US Class Current: 477/161
• CPC Class Codes: F16H 2061/0255 Solenoid valve using PWM or duty-cycle control
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 61/08 Timing control

Abstract

A line pressure regulator for a vehicular, automatic shift, multi-gear ratio transmission. An electrical signal indicative of the desired pressure is developed as a function of engine throttle and vehicle speed. The signal is continually modified by a stored correction amount, and a line pressure is generated in accordance with the modified signal so that actual and desired values of an output result from which the correction amount is calculated substantially correspond.

Claims

1. A compensated line pressure regulator for a vehicular multi-gear ratio automatic shift transmission for controlling the line pressure applied to hydraulic elements of the transmission that are operative to shift the transmission between gear ratios comprising:

means responsive to at least one vehicular operating parameter for developing a first electrical signal indicative of a desired line pressure;

means including electrically energizable means for generating a variable line pressure the magnitude of which is a function of an electrical control signal applied thereto;

means responsive to the shifting of said transmission between first and second gear ratios for generating a shift-time signal indicative of the time elapsed in shifting from said first gear ratio to said second gear ratio;

means for generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio;

means responsive to said reference signal and to said shift-time signal for generating a correction signal the magnitude of which is a function of the difference between said reference signal and said shift-time signal;

means for modifying said first electrical signal as a function of said correction signal to form a control signal; and

means for applying said control signal to said electrically energizable means whereby said first electrical signal is compensated when said transmission is shifted from said first gear ratio to said second gear ratio to adjust the line pressure to bring the actual and desired shift-times into substantial correspondence.

2. A compensated line pressure regulator for vehicular multi-gear ratio automatic shift transmission for controlling the line pressure applied to the hydraulically operated clutch elements therein that are operative to shift the transmission between gear ratios, comprising:

means responsive to at least one vehicular operating parameter for developing a first electrical signal indicative of a desired line pressure;

means including electrically energizable means for generating a variable line pressure as a function of an electrical control signal applied thereto;

means for storing a correction amount for compensating said first electrical signal;

means for modifying said first electrical signal as a function of said correction amount to form a control signal;

means for applying said control signal to said electrically energizable means for generating a transmission line pressure in accordance with said control signal;

means responsive to the shifting of said transmission between first and second gear ratios for generating a shift-time signal indicative of the time elapsed in shifting from said first gear ratio to said second gear ratio;

means for generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio;

means responsive to said reference signal and to said shift-time signal for generating a correction signal the magnitude of which is a function of the difference between said reference signal and said shift-time signal; and

means for modifying said stored correction amount as a function of said correction signal whereby said stored correction amount is updated when said transmission is shifted from said first gear ratio to said second gear ratio to bring the actual and desired shift times into substantial correspondence throughout the entire range of vehicle operation.

3. A method for controlling the line pressure of a vehicular multi-gear ratio automatic shift transmission comprising the steps of:

developing a first electrical signal indicative of a desired line pressure as a function of at least one vehicular operating parameter;

modifying said first electrical signal as a function of a stored correction amount;

generating a variable line pressure as a function of said modified first electrical signal;

continually repeating the above steps while the vehicle is in operation, to generate a line pressure in said transmission in accordance with said vehicular operating parameter and said correction amount;

generating a shift-time signal indicative of the time elapsed for said transmission to shift from a first gear ratio to a second gear ratio;

generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio; and

updating said stored correction amount as a function of the difference between said reference signal and said shift-time signal whereby said correction amount is updated when said transmission is shifted from said first gear ratio to said second gear ratio to bring said actual and desired shift-times into substantial correspondence throughout the entire range of vehicle operation.

4. A compensated line pressure regulator for a vehicular multi-gear ratio automatic shift transmission for controlling the line pressure applied to hydraulic elements of the transmission that are operative to shift the transmission between gear ratios comprising:

means responsive to engine output torque for developing a first electrical signal indicative of a desired line pressure;

means including electrically energizable means for generating a variable line pressure the magnitude of which is a function of an electrical control signal applied thereto;

means responsive to the shifting of said transmission between first and second gear ratios for generating a shift-time signal indicative of the time elapsed in shifting from said first gear ratio to said second gear ratio;

means for generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio;

means responsive to said reference signal and to said shift-time signal for generating a correction signal the magnitude of which is a function of the difference between said reference signal and said shift-time signal;

means for modifying said first electrical signal as a function of said correction signal to form a control signal; and

means for applying said control signal to said electrically energizable means whereby said first electrical signal is compensated when said transmission is shifted from said first gear ratio to said second gear ratio to adjust the line pressure to bring the actual and desired shift-times into substantial correspondence.

5. A compensated line pressure regulator for a vehicular multi-gear ratio automatic shift transmission for controlling the line pressure applied to hydraulic elements of the transmission that are operative to shift the transmission between gear ratios comprising:

means responsive to engine output torque and vehicle speed for developing a first electrical signal indicative of a desired line pressure;

means including electrically energizable means for generating a variable line pressure the magnitude of which is a function of an electrical control signal applied thereto;

means responsive to the shifting of said transmission between first and second gear ratios for generating a shift-time signal indicative of the time elapsed in shifting from said first gear ratio to said second gear ratio;

means responsive to engine output torque for generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio;

means responsive to said reference signal and to said shift-time signal for generating a correction signal the magnitude of which is a function of the difference between said reference signal and said shift-time signal;

means for modifying said first electrical signal as a function of said correction signal to form a control signal; and

means for applying said control signal to said electrically energizable means whereby said first electrical signal is compensated when said transmission is shifted from said first gear ratio to said second gear ratio to adjust the line pressure to bring the actual and desired shift-times into substantial correspondence.

6. A compensated line pressure regulator for a multi-gear ratio automatic shift transmission having a manually-operated range selector comprising:

means responsive to the position of said range selector for producing a first electrical signal indicative of a desired line pressure as a function of at least one vehicular operating parameter when said range selector is in a first position, said first signal having a predetermined value when said range selector is in a second position;

means including electrically energizable means for producing a variable line pressure as a function of an electrical control signal applied thereto;

a pressure switch in communication with said transmission for comparing the transmission line pressure with said predetermined value;

means responsive to said pressure switch for generating a correction signal when said range selector is in said second position, said correction signal is in said second position, said correction signal being a function of said comparison;

means for modifying said first electrical signal as a function of said correction signal to provide a control signal; and

means for applying said control signal to said electrically energizable means whereby said first electrical signal is compensated when said gear selector is in said second position to bring the actual and desired line pressures into substantial correspondence throughout the entire range of vehicle operation.

7. A compensated line pressure regulator for a vehicular multi-gear ratio automatic shift transmission having a manually operated range selector comprising:

means responsive to the position of said range selector for producing a first electrical signal indicative of a desired line pressure as a function of at least one vehicular operating parameter when said range selector is in a first position, said first signal having a predetermined value when said range selector is in a second position other than a drive position;

electrically energizable means for producing a variable line pressure as a function of an electrical control signal applied thereto;

means for storing a correction amount for said first electrical signal;

means for modifying said first electrical signal as a function of said stored correction amount to provide a control signal;

means for applying said control signal to said electrically energizable means whereby a line pressure is produced in said transmission in accordance with said control signal;

means for comparing the transmission line pressure with said predetermined value when said range selector is in said second position; and

means responsive to said comparison for decreasing said correction amount when said transmission line pressure exceeds said predetermined value and for increasing said correction amount when said predetermined value exceeds said transmission line pressure, whereby said first electrical signal is compensated to bring the actual and desired line pressures into substantial correspondence throughout the entire range of vehicle operation.

8. For a vehicular drive train comprising an engine, a multi-gear ratio automatic transmission, and a manual range selector for said transmission, wherein said engine may only be started when said range selector is in a specified position other than a drive position, a method for regulating the line pressure in said transmission comprising the steps of:

producing in response to the position of said range selector a first electrical signal indicative of a desired line pressure as a function of at least one vehicular operating parameter when said range selector is in a first position, said first signal having a predetermined value when said range selector is in said specified position;

modifying said first electrical signal as a function of a stored correction amount;

generating a variable line pressure as a function of said modified electrical signal;

continually repeating the above steps while the vehicle is in operation to generate a line pressure in said transmission in accordance with said vehicular operating parameter and said stored correction amount;

comparing said transmission line pressure with said predetermined value when said engine is first started; and

adjusting said stored correction amount as a function of said comparison whereby said correction amount is established when said engine is first started.

9. A method for controlling the line pressure of a vehicular multi-gear ratio automatic shift transmission comprising the steps of:

developing a first electrical signal indicative of a desired line pressure as a function of vehicle speed and engine output torque;

modifying said first electrical signal as a function of a stored correction amount;

generating a variable line pressure as a function of said modified first electrical signal;

continually repeating the above steps while the vehicle is in operation, to generate a line pressure in said transmission in accordance with said first electrical signal and said correction amount;

generating a shift-time signal indicative of the time elapsed for said transmission to shift from a first gear ratio to a second gear ratio;

generating a reference signal indicative of the desired shift-time for shifting from said first gear ratio to said second gear ratio as a function of engine output torque; and

updating said stored correction amount as a function of the difference between said reference signal and said shift-time signal whereby said correction amount is updated when said transmission is shifted from said first gear ratio to said second gear ratio to bring said actual and desired shift-times into substantial correspondence throughout the entire range of vehicle operation.