Electronic control system for multiple ratio transmission including circuit pressure control

An automatic transmission control system in a vehicle driveline that includes a throttle controlled engine and multiple ratio gearing adapted to establish multiple torque delivery paths between said engine and vehicle traction wheels;

• said gearing having a direct drive gear and two underdrive gears;
• clutch means and brake means for selectively enabling said torque flow paths to obtain ratio changes for optimum engine and transmission performance, each clutch means and each brake means including a pressure operated actuator servo;
• a hydraulic valve circuit including a pressure source and a main pressure regulator means for maintaining a desired pressure in said servos;
• a solenoid operated throttle valve means for developing a throttle valve (TV) pressure output that is representative of torque delivered through said torque flow paths;
• a solenoid operated shift valve means for establishing and disestablishing multiple pressure distribution paths to said servos;
• an electronic pressure control means comprising an electronic computer with a memory portion for storing shift strategy software logic and TV pressure control software logic executed in sequential control loops and a processor for controlling actuation of said shift valve means and for controlling the magnitude of said TV pressure in accordance with said software logic, said TV pressure being distributed to said main pressure regulator whereby the torque capacity of said clutch means and said brake means is effectively controlled;
• a vehicle speed sensor and an engine torque sensor, said sensor communicating with said processor whereby said processor responds by establishing gearing ratio shifts in accordance with stored torque and speed functions;
• said shift valve means responding to vehicle speed and engine torque sensor values under both closed and partially open engine throttle conditions to effect a downshift from direct ratio to the next underdrive ratio;
• and means for determining deceleration of said vehicle and determining said TV pressure in response to changes in deceleration of said vehicle during said downshift whereby the inertia torque that is inherent in said downshift is accommodated to effect smoothness in the downshift.

An automatic transmission pressure control system for a geared, multiple ratio transmission for an initial combustion engine powered vehicle comprising a hydrokinetic torque converter with an impeller driven by said engine and a turbine adapted to be connected to geared torque input elements of said transmission;

• a fluid pressure source in said system driven by said engine;
• clutch and brake means including multiple pressure operated clutch and brake servos for establishing and disestablishing multiple ratio torque delivery paths;
• means for sensing turbine speed during a ratio change time interval and producing a turbine speed signal;
• means for determining turbine speed derivative based upon said turbine speed signal;
• and
• means for decreasing the pressure in said servos in response to a reduction in the turbine speed derivative value at the beginning of said ratio change time interval;
• and
• means for increasing the pressure in said servos during said ratio change time interval whereby inertia torque in said transmission is modified as engine speed is reduced at the inception of said ratio change time interval and whereby a total shift change time interval is reduced by a subsequent increase in servo pressure following said servo pressure modification.

An automatic transmission pressure control system for a geared, multiple ratio transmission for an internal combustion engine powered vehicle comprising a hydrokinetic torque converter with an impeller driven by said engine and a turbine adapted to be connected to geared torque input elements of said transmission;

• a fluid pressure source in said system driven by said engine;
• clutch and brake means including multiple pressure operated clutch and brake servos in said system for establishing and disestablishing multiple ratio torque delivery paths;
• means for sensing turbine speed during a ratio change time interval and producing a turbine speed signal;
• means for determining a turbine speed derivative based upon said turbine speed signal;
• and
• means for modifying the pressure in said servos in response to changes in said turbine speed derivative value, servo pressure modifying means decreasing the pressure in said servos in response to a reduction in the turbine speed derivative value at the beginning of said ratio change time interval;
• said servo pressure modifying means increasing the pressure in said servos during said ratio change time interval whereby inertia torque in said transmission is modified as engine speed is reduced at the inception of said ratio change time interval and whereby a total shift change time interval is reduced by a subsequent increase in servo pressure following said servo pressure modification;
• said means for modifying servo pressure including means for multiplying said servo pressure by a factor that is less than unity when said turbine speed derivative is less than a calibrated value.

An automatic transmission pressure control system for a geared, multiple ratio transmission for an internal combustion engine powered vehicle comprising a hydrokinetic torque converter with an impeller driven by said engine and a turbine adapted to be connected to geared torque input elements of said transmission;

• a fluid pressure source in said system driven by said engine;
• clutch and brake means including multiple pressure operated clutch and brake servos in said system for establishing and disestablishing multiple ratio torque delivery paths;
• means for sensing turbine speed during a ratio change time interval and for producing a turbine speed signal;
• means for determining a turbine speed derivative value based upon said turbine speed signal;
• and
• means for modifying the pressure in said servos in response to changes in said turbine speed derivative value, said servo pressure modifying means decreasing the pressure in said servos in response to a reduction in said turbine speed derivative value at the beginning of said ratio change time interval;
• said servo pressure modifying means increasing the pressure in said servos during said ratio change time interval whereby inertia torque in said transmission is modified as engine speed is reduced at the inception of said ratio change time interval and whereby a total shift change time interval is reduced by a subsequent increase in servo pressure following said servo pressure modification;
• said means for modifying servo pressure including a means for multiplying said servo pressure by a factor that is greater than unity when said turbine speed derivative is greater than a calibrated value;
• and means for multiplying said servo pressure by a factor that is less than unity when said turbine speed derivative is less than a calibrated value.

A pressure control system for an automatic transmission control fluid circuit in an automotive vehicle having a throttle controlled internal combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths between said engine and a driven shaft;
• clutch means and brake means in said circuit for establishing and disestablishing said torque flow paths and fluid pressure operated clutch and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a vehicle speed sensor means for establishing a vehicle speed signal;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal to alter the pressure of said servo means;
• a shift control valve means including shift solenoid valves for controlling selectively actuation of said servo means whereby ratio changes may be effected in a range of ratios between a low ratio and a high ratio including at least one underdrive ratio in response to changes in said signal;
• means for calculating a signal value for the static torque transferred through said transmission for each torque flow path, said static torque being equal to the combustion torque of said engine, and means for calculating a signal value for the inertia torque caused by a change in the engine speed during a shift;
• a microprocessor means communicating with said throttle valve means for actuating said throttle valve means including means for storing in addressable data registers the functional relationships between the static torque capacity and said engine combustion torque signal values, said means for calculating said static torque signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during the ratio shifts including other addressable data registers in said microprocessor containing functional relationship between the engine throttle position and an inertia torque signal value;
• and
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for said servo means.

A pressure control system for an automatic transmission control fluid circuit in an automotive vehicle having a throttle controlled internal combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths with separate ratios between said engine and a driven shaft;
• clutch means and brake means for establishing and disestablishing said torque flow paths and fluid pressure operated clutch and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal to alter the pressure of said servo means;
• shift control valve means including shift solenoid valves for controlling selectively actuation of said servo means whereby ratio changes may be effected in a range of ratios between low ratio and a high ratio including at least one underdrive ratio;
• means for calculating a signal value for static torque transferred through said transmission for each torque flow path, said static torque being equal to combustion torque of said engine, and means for calculating a signal value for inertia torque resulting from a change in engine speed during a shift;
• a microprocessor means communicating with said throttle valve means for actuating said throttle valve means including means for storing in addressable data registers functional relationships between static torque capacity and said engine combustion torque signal values, said means for calculating said static signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during ratio shifts including other addressable data registers in said microprocessor containing functional relationship between engine throttle position and an inertia torque signal values;
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for said servo means;
• a timer means for establishing a calibrated time for a ratio change to occur following initiation of a ratio change to said one underdrive ratio from a higher ratio;
• and
• means initiated by actuation of said timer for augmenting the effective torque signal value at the beginning of said ratio change relative to the effective torque signal value calculated during a final stage of said ratio change.

A pressure control system for an automatic transmission control fluid circuit in an automative vehicle having a throttle controlled internal combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths with separate ratios between said engine and a driven shaft;
• clutch means and brake means for establishing and disestablishing said torque flow paths and fluid pressure operated clutch and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal to alter the pressure of said servo means;
• a shift control valve means including shift solenoid valves for controlling selectively actuation of said servo means whereby ratio changes may be effected in a range of ratios between low ratio and a high ratio including at least one underdrive ratio;
• means for calculating a signal value for static torque transferred through said transmission for each torque flow path, said static torque being equal to combustion torque of said engine and, means for calculating a signal value for inertia torque resulting from a change in engine speed during a shift;
• a microprocessor means communicating with said throttle value means for actuating said throttle valve means including means for storing in addressable data registers functional relationships between static torque capacity and said engine combustion torque signal values, said means for calculating said static torque signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during ratio shifts including other addressable data registers in said microprocessor containing functional relationship between engine throttle position and inertia torque signal values;
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for said servo means;
• and
• means for adding to said inertia torque signal value an incremental torque signal value for upshifts whereby the effective inertia torque signal value is greater for upshifts than for downshifts.

A pressure control system for an automatic transmission control fluid circuit in an automotive vehicle having a throttle controlled internal combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths with separate ratios between said engine and a driven shaft;
• clutch means and brake means for establishing and disestablishing said torque flow paths and fluid pressure operated clutch and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal to alter the pressure of said servo means;
• a shift control valve means including shift solenoid valves for controlling selectively actuation of said servo means whereby ratio changes may be effected in a range of ratios between low ratio and a high ratio including at least one underdrive ratio;
• means for calculating a signal value for static torque transferred through said transmission for each torque flow path, said static torque being equal to combustion torque of said engine, and means for calculating a signal value for inertia torque resulting from a change in engine speed during a shift;
• a microprocessor means communicating with said throttle valve means for actuating said throttle valve means including means for storing in addressable data registers functional relationships between static torque capacity and said engine combustion torque signal values, said means for calculating said static torque signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during ratio shifts including other addressable data registers in said microprocessor containing functional relationship between engine throttle position and inertia torque signal values;
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for said servo means;
• and
• means for adding to said inertia torque signal value an incremental torque signal value for upshifts whereby the effective dynamic torque signal value is greater for upshifts than for downshifts;
• and
• a timer means for controlling the time said incremental torque signal valve is added to said inertia torque signal value during an upshift following the initiation of said upshift.

A pressure control system for an automatic transmission control fluid circuit in an automotive vehicle having a throttle controlled combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths between said engine and a driven shaft;
• clutch means and brake means in said circuit for establishing and disestablishing said torque flow paths and fluid pressure operated clutch servo means and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal value to alter the pressure of said servo means;
• a shift control valve means including shift solenoid valves for controlling selectively actuation of said servo means whereby ratio changes may be effected in a range of ratios between low ratio and a high ratio including at least one underdrive ratio;
• means for calculating a signal value for static torque transferred through said transmission for each torque flow path, said static torque being equal to combustion torque of said engine, and means for calculating a signal value for inertia torque resulting from a change in engine speed during a shift;
• a microprocessor means communicating with said throttle valve means for actuating said throttle valve means including means for storing in addressable data registers functional relationships between static torque capacity and said engine combustion torque signal values, said means for calculating said static torque signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during ratio shifts including other addressable data registers in said microprocessor containing functional relationship between engine throttle position and inertia torque signal values;
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for each of said servo means;
• the torque transmitting capacity of said clutch means and said brake means being proportional to circuit pressure transferred to said clutch servo means and said brake servo means by said shift control valve means, the torque capacity of one servo means falling and the torque capacity of another servo means increasing during an upshift from one ratio to a higher ratio following initiation of said upshift;
• and timer means for measuring the time required to complete the torque capacity decrease of said one servo during said upshift;
• said processor having register locations for storing servo pressure multipliers that are addressable and used by said torque signal value calculating means;
• a low multiplier being fetched when the time measured by said timer means is less than a calibrated range of values and a higher multiplier being fetched when the time measured by said timer means is greater than a calibrated range of values.

A pressure control system for an automatic transmission control fluid circuit in an automotive vehicle having a throttle controlled combustion engine, said circuit having a pressure source and a main pressure regulator valve;

• multiple ratio gearing adapted to establish torque flow paths between said engine and a driven shaft;
• clutch means and brake means in said circuit for establishing and disestablishing said torque flow paths and fluid pressure operated clutch servo means and brake servo means in said fluid circuit for actuating selectively said clutch means and said brake means;
• a solenoid operated throttle valve means for establishing a torque signal that is a measure of engine torque, said throttle valve means communicating with said main pressure regulator valve whereby the latter responds to changes in said torque signal valve to alter the pressure of said servo means;
• a shift control valve means including shift solenoid valves for controlling selectively actuation of said clutch servo means and said brake servo means whereby ratio changes may be effected in a range of ratios between low ratio and a high ratio including at least one underdrive ratio;
• means for calculating a signal value for static torque transferred through said transmission for each torque flow path, said static torque being equal to combustion torque of said engine, and means for calculating a signal value for inertia torque resulting from a change in engine speed during a shift;
• a microprocessor means communicating with said throttle valve means for actuating said throttle valve means including means for storing in addressable data registers functional relationships between static torque capacity and said engine combustion torque signal values, said means for calculating said static torque signal value including said addressable data registers;
• each ratio shift corresponding to a separate one of said functional relationships and having a discrete slope value and a discrete constant intercept value;
• said means for calculating an inertia torque signal value during ratio shifts including other addressable data registers in said microprocessor containing functional relationship between engine throttle position and inertia torque signal values;
• means for adding said inertia torque signal value and said static torque signal value to obtain an effective torque signal output received by said solenoid operated valve means to establish optimum pressure control for each of said servo means;
• a timer means for establishing a calibrated time for a ratio change to occur following initiation of a ratio change to said one underdrive ratio from a higher ratio;
• means initiated by actuation of said timer means for augmenting the effective torque signal value at the beginning of said ratio change relative to the effective torque signal value calculated during a final stage of said ratio change;
• the torque transmitting capacity of each servo means being proportional to circuit pressure transferred to it by said shift control valve means, the torque capacity of one servo means falling and the torque capacity of another servo means increasing during an upshift from one ratio to a higher ratio following initiation of said upshift;
• and timer means for measuring the time required to complete the torque capacity decrease of said one servo means during said upshift;
• said processor having register locations for storing servo pressure multipliers that are addressable and used by said torque signal calculating means;
• a low multiplier being fetched when the time measured by said timer means is less than a calibrated range of values and a higher multiplier being fetched when the time measured by said timer means is greater than a calibrated range of values.