Abstract: A controller commands an engine torque level in response to a driver demanded torque based on an accelerator pedal position. If the driver demanded torque decreases rapidly during or just prior to a torque phase of a shift, the controller commands the engine to temporarily generate torque exceeding the driver demand. The controller sets a nominal engine torque equal to the driver demand torque before the rapid decrease, slowly decreases the nominal engine torque during the torque phase, and decreases the nominal torque at progressively faster rates during the inertia phase to bring the nominal torque back into agreement with the driver demanded torque. The commanded engine torque is based on the nominal torque, but may be less than the nominal torque during the inertia phase to permit the engine speed to decrease faster.

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: When a vehicle driver commands a change in direction of motion while the vehicle is moving above a threshold speed, a controller first applies a braking force to slow the vehicle below the threshold speed and then establishes a power flow path associated with the opposite direction of motion. The braking force may be applied by wheel brakes or, in some situations, by a transmission clutch. This method prevents an engine stall, overheating of oncoming clutch, and excessive delay.

Abstract: While a transmission range selector is in a Park position, a controller engages multiple transmission shift elements to place the transmission in a tie-up state. In the tie-up state, both the transmission output shaft and the turbine shaft are held against rotation by the shift elements. To transition from Park to Drive, the controller releases one of the shift elements to place the transmission in a 1st gear state. To transition from Park to Reverse, the controller releases a different one of the shift elements to place the transmission in a reverse state. The controller may wait until the driver releases the brake pedal to release the shift element.