Abstract: A vehicle includes an accelerator pedal moveable across a plurality of predefined positions and a controller programmed to, responsive to the pedal reaching a tip-in position, command a downshift to a downshift gear from an initial gear. A difference between the initial and downshift gears exceeds a number of predefined positions crossed upon moving to the tip-in position when a rate of change of pedal position exceeds a predefined threshold.

Abstract: A transmission includes a latch valve with latched and de-latched states. In the de-latched state, the latch valve directs a control pressure to a clutch apply circuit. In the latched state, which is entered in response to a control pressure higher than a latch pressure, the latch valve directs a line pressure to the clutch apply circuit. A controller manages the transition from latched to de-latched differently depending upon the transmission input torque and gear state. At high transmission input torque, the controller first reduces the control pressure to rapidly accelerate a spool in the latch valve, and then increases the control pressure to prevent clutch slip. At low torque, the controller reduced the pressure to an intermediate value during the transition and then reduces it again. At moderate torques, the controller reduces the pressure directly to a target pressure in a single step.

Abstract: A transmission includes a latch valve with latched and de-latched states. In the de-latched state, the latch valve directs a control pressure to a clutch apply circuit. In the latched state, which is entered in response to a control pressure higher than a latch pressure, the latch valve directs a line pressure to the clutch apply circuit. A controller manages the transition from latched to de-latched differently depending upon the transmission input torque and gear state. At high transmission input torque, the controller first reduces the control pressure to rapidly accelerate a spool in the latch valve, and then increases the control pressure to prevent clutch slip. At low torque, the controller reduced the pressure to an intermediate value during the transition and then reduces it again. At moderate torques, the controller reduces the pressure directly to a target pressure in a single step.

Abstract: A method for controlling engine temperature of an engine with a wide dynamic range is disclosed. In one example, the derivative of an engine temperature is assessed by a controller. The controller may adjust engine actuators to limit engine temperature in response to the derivative.

Abstract: A method for controlling engine temperature of an engine with a wide dynamic range is disclosed. In one example, the derivative of an engine temperature is assessed by a controller. The controller may adjust engine actuators to limit engine temperature in response to the derivative.

Abstract: A method for controlling engine temperature of an engine with a wide dynamic range is disclosed. In one example, the derivative of an engine temperature is assessed by a controller. The controller may adjust engine actuators to limit engine temperature in response to the derivative.

Abstract: A method for controlling engine temperature of an engine with a wide dynamic range is disclosed. In one example, the derivative of an engine temperature is assessed by a controller. The controller may adjust engine actuators to limit engine temperature in response to the derivative.

Abstract: A control strategy and method for controlling friction element engagement and disengagement time for an automatic transmission when the transmission is operating at cold ambient temperatures. During drive-to-reverse or reverse-to-drive friction element engagements with power on, the strategy compensates for a tendency of an oncoming friction element to gain capacity before an off-going clutch loses capacity, thereby avoiding a potential friction element tie-up condition when the transmission is operated with intermediate or high levels of engine torque as the friction elements are sequentially engaged and disengaged during cold rock cycling.

Abstract: A method is described for limiting a change in torque transmitted through a vehicle powertrain when in a predetermined range. Such a method minimizes transmission gear separation, or “clunk”. In one approach, the rate cf change of powertrain output is limited when powertrain output is near zero transmitted torque. The limitation is not used under other circumstances so as not to hinder driver performance.

Abstract: A vehicle control system is described for controlling a torque converter coupled to an engine. The controller engages the torque converter before negative powertrain output becomes less than a predetermined value. Such an approach allows for torque converter locking in the negative powertrain output region. Such an approach is especially suited to vehicles having certain torque converters, which are difficult to lock at large negative torque values.

Abstract: A method for controlling the capacity of friction clutches and brakes in a multiple-ratio vehicle transmission and for simultaneously establishing ratio shift point scheduling to effect a desired vehicle speed at which ratio changes occur while the vehicle is in a traction control mode. The method includes calculating a synthetic throttle setting that is used to establish clutch and brake capacity control and wherein separate ratio shift schedules are used for normal operation and for traction control operation, the engine torque required during operation in the traction control mode determining the vehicle speed at which shifts occur for each gear ratio whereby the shift schedule during operation in the traction control mode can be calibrated independently of the throttle position required for optimum clutch and brake capacity control.

Abstract: A control strategy and method for controlling friction element engagement and disengagement time for an automatic transmission when the transmission is operating at cold ambient temperatures. During drive-to-reverse or reverse-to-drive friction element engagements with power on, the strategy compensates for a tendency of an oncoming friction element to gain capacity before an off-going clutch loses capacity, thereby avoiding a potential friction element tie-up condition when the transmission is operated with intermediate or high levels of engine torque as the friction elements are sequentially engaged and disengaged during cold rock cycling.

Abstract: A method for controlling an engine coupled to a transmission is described. The method is especially suited for a transmission having at least one gear in which an over-running clutch is present. The invention describes a method for adjusting an engine operating parameter to maintain transmission input speed at or below a synchronous transmission input speed when the transmission is in the gear with the over-running clutch. The synchronous transmission input speed is based on transmission state and transmission output speed. Alternatively, vehicle speed can be used in place of transmission output speed.

Abstract: A method is described for limiting a change in torque transmitted through a vehicle powertrain when in a predetermined range. Such a method minimizes transmission gear separation, or “clunk”. In one approach, the rate of change of powertrain output is limited when powertrain output is near zero transmitted torque. The limitation is not used under other circumstances so as not to hinder driver performance.

Abstract: A method is described for controlling a powertrain of a vehicle. In particular, the method attempts to minimize transmission gear separation, or “clunk”. Under some circumstances, it is determined whether torque converter output speed has become greater than torque converter input speed while the torque converter was unlocked. Such a situation represents a change from positive powertrain output to negative powertrain output. If such a situation has occurred, under certain circumstances, the torque converter is then locked.

Abstract: A method for controlling the capacity of friction clutches and brakes in a multiple-ratio vehicle transmission and for simultaneously establishing ratio shift point scheduling to effect a desired vehicle speed at which ratio changes occur while the vehicle is in a traction control mode. The method includes calculating a synthetic throttle setting that is used to establish clutch and brake capacity control and wherein separate ratio shift schedules are used for normal operation and for traction control operation, the engine torque required during operation in the traction control mode determining the vehicle speed at which shifts occur for each gear ratio whereby the shift schedule during operation in the traction control mode can be calibrated independently of the throttle position required for optimum clutch and brake capacity control.

Abstract: A control strategy for a multiple-ratio transmission for an automotive vehicle comprising a shift valve system that responds to shift valve signals developed by a microprocessor controller, the controller being in communication with engine sensors indicating engine operating variables and transmission sensors indicating transmission operating variables, the shift valve system responding to shift signals developed by the microprocessor during coasting downshift of the vehicle from one gear ratio to a lower gear ratio with a closed engine throttle whereby torque reversals are avoided during coast-down, thereby eliminating inertia torque changes to improve the smoothness of coasting downshifts during cold engine operation.