Abstract: In order to pre-stage a clutch piston in preparation for clutch engagement, a controller commands a high current to a Casting Integrated Direct Acting Solenoid (CIDAS) valve. This staging is performed in two distinct phases wherein the current is higher in the first phase than in the second phase. Staging the piston in this manner reduces the staging time and reduces the variability of the staging time. The duration of the first phase may be adjusted based on a number of parameters including, the length of a preceding engine off period, the number of clutch applications since the engine off period, a fluid temperature, and a length of time since a preceding engagement of the clutch.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: A system controlling pressure in a transmission including a variable displacement pump, a circuit carrying fluid from the pump to the transmission, a valve using fluid in said circuit to regulate pressure that controls displacement of the pump, a source of control pressure including an accumulator, a first spring acting with said source causing the valve to change the regulated pressure, and a second spring acting with feedback pressure from said circuit to oppose said change.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: A sliding vane pump includes a passageway that fluidly connects one or more pumping chambers to a side chamber. The passageway pressurizes the side chamber. This fluid pressure exerts a force that counteracts the force caused by pressure differences between the outlet pumping chambers and the inlet pumping chambers. At high speed, part of the side chamber is pressurized by the smallest volume outlet pumping chamber while another portion of the side chamber is pressurized by the largest volume outlet chamber. This results in a force counteracting an uncommanded displacement decrease of the pump.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: A motor vehicle includes a transmission having a control valve and a torque converter with a lock-up clutch. The control valve is configured to control both a mode and an apply pressure of the lock-up clutch. The control valve includes a valve body and a plunger moveable within the valve body. When the plunger is in a first position, the lock-up clutch is in a release mode and, when the plunger is in a second position, the lock-up clutch is in an apply mode and movement of the plunger relative to the second position controls the apply pressure.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: An automatic transmission uses 6 shift elements applied in combinations of four to establish ten forward speed ratios and a reverse speed ratio. The automatic transmission uses a hydraulic control system to control engagement of the six elements, control engagement of a torque converter bypass clutch, control engagement of a parking pawl, and to provide fluid for a hydrodynamic torque converter and for lubrication. The parking pawl is disengaged in response to engagement of two of the six shift elements and remains disengaged in response to engagement of other shift elements. A single valve controls several different functions associated with the two-pass torque converter. Pressurized fluid is provided by a variable displacement engine driven pump and also by an electric pump. A priority valve reduces lubrication flow when other fluid demands are high as indicated by the pump displacement control circuit.

Abstract: A control valve for an automatic transmission includes a valve body including a chamber and a control pressure port, metering edges formed in the valve body at the control pressure port, a reference surface formed in the valve body, a spool displaceable along the chamber, and a solenoid module including a pin for displacing the spool, and located in the chamber by contact with the reference surface.

Abstract: A vehicle according to the present disclosure includes a shift-by-wire transmission, a pressure source configured to selectively provide hydraulic pressure in the absence of engine power, an internal combustion engine, and a controller. The shift-by-wire transmission includes a hydraulic actuator, and the electric pump is in fluid communication with the actuator. The controller is configured to, in response to a driver input and the engine being off, control the pressure source to provide hydraulic pressure to the hydraulic actuator.

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 torque converter clutch (TCC) control valve system for a motor vehicle transmission includes a dual valve assembly with a first exhaust line that opens to air and a TCC control valve assembly with a second exhaust line that opens to air. The TCC control valve assembly communicates with the dual valve assembly through a fluid line, and the TCC control valve assembly further communicates with a torque converter having a lockup clutch. When the lockup clutch is in a faulted open state, air is drawn into the dual valve assembly through the first exhaust line. The air flows through the dual valve assembly and from the dual valve assembly though the fluid line to portions of the TCC control valve assembly, and from the TCC control valve assembly to the torque converter. The air replaces hydraulic fluid in the torque converter, and the displaced hydraulic fluid from the torque converter exits through the second exhaust line.

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 control valve for an automatic transmission includes a valve body and a solenoid module. The body has a chamber, control pressure port, exhaust port, and reference surface. Metering edges are formed in the body at the control port. A spring transmits force between first and second spools in the chamber. The solenoid module has a pin for displacing the first spool and is located by contact with the reference surface. The solenoid module also has a first stop surface limiting pin movement and a second stop surface contacting the reference surface.

Abstract: A vehicle includes both a transmission park mechanism and an electronic parking brake. As a failure management strategy, a controller monitors vehicle movement to verify that the park mechanism is successfully restraining the vehicle against movement. Specifically, when the driver releases the brake pedal with the transmission park mechanism commanded to restrain the vehicle, the controller waits for a predetermined amount of time. If the vehicle moves during this time, the controller commands application of the electronic parking brake. The controller may also command application of the electronic parking brake if the vehicle does not come to a stop after the transmission park mechanism is commanded to restrain the vehicle.

Abstract: A hydraulic control system includes a primary sump and an auxiliary sump. When the transmission fluid is warm, fluid remains in the auxiliary sump reducing the volume of oil in circulation throughout the transmission to reduce parasitic losses. An oil control valve is designed to block flow of oil from the auxiliary sump to the primary sump when the fluid is warm and to allow flow when the fluid is cold. The oil control valve also responds to transmission line pressure. At moderate temperatures, fluid is held in the auxiliary sump when the engine is running but drains back to the primary sump when the engine is off.

Abstract: A vehicle includes both a transmission park mechanism and an electronic parking brake. As a failure management strategy, a controller monitors vehicle movement to verify that the park mechanism is successfully restraining the vehicle against movement. Specifically, when the driver releases the brake pedal with the transmission park mechanism commanded to restrain the vehicle, the controller waits for a predetermined amount of time. If the vehicle moves during this time, the controller commands application of the electronic parking brake. The controller may also command application of the electronic parking brake if the vehicle does not come to a stop after the transmission park mechanism is commanded to restrain the vehicle.

Abstract: A hydraulic control system provides lubrication fluid to a gearbox via two flow paths in parallel. One of the flow paths includes a passive thermal valve in series with a heat exchanger. When the fluid temperature is elevated, the thermal valve opens such that fluid flows through the heat exchanger for cooling. The thermal valve restricts flow to the heat exchanger when transmission fluid is in a normal operating temperature range, reducing flow demands. When the flow demands are reduced, a variable displacement pump requires less torque improving fuel economy. The thermal valve may also open when the fluid is below the normal operating temperature such that the heat exchanger heats the fluid. The parallel path may include a regulator valve. When the pressure of fluid in the lubrication circuit is elevated, the regulator valve reduces flow through the parallel path and may also divert flow to a sump.