Automatic transmission gear shift control during power reduction
AssigneeFord Motor Company
InventorsPeter J. Grutter, Matthew J. Gerhart, Matthew J. Gladd, John A. Cushing
Life of this patent
Estimating the term…
Abstract
A method and system for controlling gear ratio changes of a transmission operating in a powertrain with an internal combustion engine controlled by an engine throttle and having a device, such as traction assist system, that alters engine torque from that corresponding to the position of the throttle. The control substitutes a synthetic throttle position for actual throttle position during a traction assist event. Gearshifts occur with reference to a schedule relating the desired gear, vehicle speed, and synthetic throttle position.
Claims10
In a powertrain including a multiple gear automatic transmission, an engine controlled by a variable-position throttle and a device enabled part-time to alter the magnitude of power produced by the engine from that corresponding to the throttle position, a method comprising the steps of:
- defining a first function relating the operating condition of the powertrain, partially represented by throttle position, to a corresponding desired gear;
- defining a second function relating engine speed and net engine torque to a corresponding synthetic throttle position;
- determining net engine torque, vehicle speed, engine speed, and throttle position;
- determining synthetic throttle position from the second function;
- while the device is enabled, substituting synthetic throttle position for throttle position and determining the desired gear from the first function;
- and
- controlling the transmission to produce said desired gear, so determined.
In an automotive vehicle powertrain including an automatic transmission that operates in multiple gears in accordance with the engaged and disengaged state of friction elements, an engine controlled by a variable-position throttle, a device enabled part-time to alter the magnitude of power produced by the engine from that corresponding to the throttle position, and a computer accessible to an electronic memory, a method comprising the steps of:
- storing in memory a first function relating a range of operating conditions of the powertrain defined by throttle position and vehicle speed to corresponding desired gears;
- storing in memory a second function relating engine speed and net engine torque to corresponding synthetic throttle positions;
- repetitively determining current net engine torque, current vehicle speed, current engine speed, and current throttle position;
- accessing the memory with current engine speed and current net engine torque and determining from the second function the corresponding synthetic throttle position;
- while the device is enabled, accessing memory with current vehicle speed and said corresponding synthetic throttle position and determining from the first function the current desired gear;
- and
- producing a signal from the computer commanding a change in the engaged and disengaged state of the friction elements to produce said desired gear, so determined.
A system for controlling an automatic transmission that operates in multiple gears, comprising:
- an engine controlled by a variable-position throttle;
- a traction assist device enabled part-time to alter the magnitude of power produced by the engine from that corresponding to the throttle position, receiving signals representing the speed of the vehicle wheels, determining the occurrence of wheel slippage therefrom, and producing a command signal to alter the magnitude of power produced by the engine from that corresponding to the throttle position;
- sensors repetitively producing signals representing current vehicle speed, current engine speed, and current throttle position;
- an electronic memory containing control algorithms, a first function relating a range of operating conditions of the powertrain defined by throttle position and vehicle speed to corresponding desired gears, and a second function relating engine speed and net engine torque to corresponding synthetic throttle positions;
- and
- an electronic microprocessor adapted to receive as input said sensor signals, process information derived from said signals, execute control algorithms, determine current net engine torque, and produce a command signal representing the desired gear produced by the transmission.
Dependencies are inferred from the claim text.