초록 ▼

A hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices a

A hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio.

대표청구항 ▼

1. A method of controlling a dual clutch and a plurality of synchronizers in a transmission, the method comprising: selecting an actuator from a plurality of actuators that actuates a synchronizer of one of the plurality of synchronizers or engages a clutch from one of a first and a second clutch of

1. A method of controlling a dual clutch and a plurality of synchronizers in a transmission, the method comprising: selecting an actuator from a plurality of actuators that actuates a synchronizer of one of the plurality of synchronizers or engages a clutch from one of a first and a second clutch of the dual clutch in order to achieve a desired speed ratio in the transmission;actuating the selected clutch of the dual clutch with a pressurized hydraulic fluid;commanding a first synchronizer control solenoid to provide a first supply of hydraulic fluid to a first input of a first mode valve, wherein the first synchronizer control solenoid is in downstream fluid communication with a source of pressurized hydraulic fluid;commanding a second synchronizer control solenoid to provide a second supply of hydraulic fluid to a second input of the first mode valve, wherein the second synchronizer control solenoid is in downstream fluid communication with the source of pressurized hydraulic fluid;actuating the first mode valve to one of a first position and a second position to direct the first and second supplies of hydraulic fluid to one of a second mode valve and a third mode valve, wherein actuating the first mode valve in the first position directs the first supply of hydraulic fluid from the first input of the first mode valve to a first output of the first mode valve and directs the second supply of hydraulic fluid from the second input of the first mode valve to a third output of the first mode valve, and wherein actuating the first mode valve in the second position directs the first supply of hydraulic fluid from the first input of the first mode valve to a second output of the first mode valve and directs the second supply of hydraulic fluid from the second input of the first mode valve to a fourth output of the first mode valve, and wherein the first output of the first mode valve is in fluid communication with a first input of the second mode valve, the second output of the first mode valve is in fluid communication with a first input of the third mode valve, the third output of the first mode valve is in fluid communication with a second input of the second mode valve, and the fourth output of the first mode valve is in fluid communication with a second input of the third mode valve; andactuating at least one of the first, second, and third mode valves to direct the first and second supplies of hydraulic fluid to the selected actuator to control the position of the actuator, wherein actuating at least one of the first, second, and third mode valves directs the first supply of hydraulic fluid from the first input of the respective mode valve to a first side of the piston of the selected actuator and directs the second supply of hydraulic fluid from the second input of the respective mode valve to the second side of the piston of the selected actuator;determining a target clutch torque to be provided by the selected clutch, determining a target clutch position of the selected clutch that will provide the target clutch torque using a clutch torque to clutch actuator position relationship, selecting a first pressure of a hydraulic fluid to be provided by a pressure control solenoid from the higher of a pressure required to enable a required amount of flow through the flow control solenoid to actuate the clutch, a pressure required to hold the target clutch torque on the clutch, and a pressure required to shift a mode valve, commanding the pressure control solenoid to provide a third supply of hydraulic fluid at the selected first pressure to establish an upstream side of a pressure potential across a flow control solenoid that is downstream of the pressure control solenoid, sensing a position of the clutch actuator, estimating a second pressure of a fourth supply of hydraulic fluid at the clutch actuator using a predetermined clutch actuator position to clutch pressure relationship, calculating a pressure potential across the flow control solenoid by subtracting the second pressure from the first pressure, wherein the pressure potential across the flow control solenoid creates a relationship between a control signal and a flow rate from the flow control solenoid, determining a flow rate of the third supply of hydraulic fluid to be provided by the flow control solenoid that will position the clutch actuator to the target clutch position, determining a control signal to be sent to the flow control solenoid to provide the flow rate of the third supply of hydraulic fluid, and communicating the control signal to the flow control solenoid to move the clutch actuator to the target clutch position to provide the target clutch torque. 2. The method of claim 1 wherein the plurality of synchronizers are actuated by a first, a second, a third, and a fourth actuator of the plurality of actuators each having a first input and a second input, wherein the first inputs of the first and second actuators are in respective fluid communication with the first and fourth outputs of the second mode valve, the second inputs of the first and second actuators are in respective fluid communication with the third and the second outputs of the second mode valve, the first inputs of the third and fourth actuators are in respective fluid communication with the first and fourth outputs of the third mode valve, and the second inputs of the third and fourth actuators are in respective fluid communication with the third and the second outputs of the third mode valve. 3. The method of claim 1 wherein actuating the selected clutch includes actuating a clutch actuator in downstream fluid communication with a clutch flow control solenoid, the clutch flow control solenoid being in downstream fluid communication with a clutch pressure control solenoid that is in downstream fluid communication with the source of hydraulic fluid. 4. The method of claim 1 wherein actuating the selected clutch includes controlling the pressure of the hydraulic fluid to the selected clutch, calculating a command pressure level for a clutch pressure control solenoid based on a clutch torque to actuator position relationship, estimating the clutch pressure of the selected clutch from the position of the selected clutch to establish a desired pressure required to enable a required amount of flow through the flow control solenoid to actuate the clutch, and applying a command current to the clutch flow control solenoid such that the selected clutch of the dual clutch engages with a desired torque. 5. The method of claim 1 further comprising maintaining the pressure potential across the flow control solenoid by commanding the pressure control solenoid to exhaust, maintain, or provide added pressure to the flow control solenoid. 6. The method of claim 1 wherein the target clutch torque is an amount of torque required to perform an action within the transmission including performing a shift event or maintaining a gear ratio. 7. The method of claim 1 wherein the clutch torque to clutch actuator position relationship is learned as the transmission is operating by relating a engine torque while the clutch is slipping to a position of the clutch actuator. 8. The method of claim 1 further comprising adjusting the clutch torque to clutch actuator position relationship using closed-loop position control. 9. The method of claim 1 wherein sensing the clutch actuator position includes sensing the clutch actuator position using a clutch position sensor. 10. The method of claim 1 further including modulating pressure levels of the first and second supplies of hydraulic fluid to vary a net force on the piston of the selected actuator and adjust the speed of the piston as the actuator actuates a respective synchronizer. 11. The method of claim 10 further including monitoring a position of the selected actuator as the actuator moves from an initial position to a final position, reducing the net force on the piston when the actuator is approaching a first intermediate position in order to reduce a velocity of the actuator, increasing the net force on the piston when the actuator is at the first intermediate position, determining whether the actuator has reached a second intermediate position, decreasing the net force on the piston when the actuator is at the second intermediate position, determining whether the actuator has reached the final position, commanding a zero net force on the piston when the actuator has reached the final position. 12. The method of claim 11 wherein the first intermediate position is the position of the synchronizer where a synchronizer sleeve contacts a blocker ring in the synchronizer. 13. The method of claim 11 wherein the net force is selected to move the actuator to the commanded position in a desired amount of time and to overcome a detent spring and actuator drag. 14. The method of claim 11 wherein the final position is where a synchronizer sleeve contacts and stops on a gear. 15. The method of claim 11 further comprising reducing a pressure of the first and second supplies of hydraulic fluid to zero after the synchronizer is at the final position. 16. The method of claim 11 wherein the commands on the synchronizer control solenoids to vary the net force on the piston are adjusted using actuator position and velocity feedback. 17. A method of synchronizing a shaft to a gear in a transmission of a motor vehicle, the method comprising: monitoring a position of an actuator configured to move a synchronizer coupled to the shaft;actuating a first mode valve to one of a first position and a second position to direct a first and a second supply of hydraulic fluid to one of a second mode valve and a third mode valve, wherein actuating the first mode valve in the first position directs the first supply of hydraulic fluid from a first input of the first mode valve to a first output of the first mode valve and directs the second supply of hydraulic fluid from a second input of the first mode valve to a third output of the first mode valve, and wherein actuating the first mode valve in the second position directs the first supply of hydraulic fluid from the first input of the first mode valve to a second output of the first mode valve and directs the second supply of hydraulic fluid from the second input of the first mode valve to a fourth output of the first mode valve, and wherein the first output of the first mode valve is in fluid communication with a first input of the second mode valve, the second output of the first mode valve is in fluid communication with a first input of the third mode valve, the third output of the first mode valve is in fluid communication with a second input of the second mode valve, and the fourth output of the first mode valve is in fluid communication with a second input of the third mode valve;actuating at least one of the first, second, and third mode valves to direct the first and second supplies of hydraulic fluid to the actuator to control the position of the actuator, wherein actuating at least one of the first, second, and third mode valves directs the first supply of hydraulic fluid from the first input of the at least one of the first, second, and third mode valves to a first side of a piston of the actuator and directs the second supply of hydraulic fluid from the second input of the at least one of the first, second, and third mode valves to the second side of the piston of the actuator; andcommanding a first synchronizer control solenoid to provide a first supply of hydraulic fluid to the first input of a first mode valve, wherein the first synchronizer control solenoid is in downstream fluid communication with a source of pressurized hydraulic fluid;commanding a second synchronizer control solenoid to provide a second supply of hydraulic fluid to the second input of the first mode valve, wherein the second synchronizer control solenoid is in downstream fluid communication with the source of pressurized hydraulic fluid;modulating pressure levels of the first and second supplies of hydraulic fluid to vary a net force on the piston of the actuator and adjust the speed of the piston as the actuator actuates the synchronizer;monitoring a position of the actuator as the actuator moves from an initial position to a final position;reducing the net force on the piston when a synchronizer sleeve is approaching a blocker ring in the synchronizer in order to reduce a velocity of the actuator;increasing the net force on the piston when the synchronizer sleeve contacts the blocker ring in the synchronizer;determining whether the actuator has reached an intermediate position, decreasing the net force on the piston when the actuator is at the intermediate position;determining whether the synchronizer sleeve has contacted a gear; andcommanding a zero net force on the piston when the synchronizer is fully engaged, andwherein the commands on the synchronizer control solenoids to vary the net force on the piston are adjusted using actuator position and velocity feedback. 18. The method of claim 17 wherein selecting the mode for the first mode valve further includes controlling a first mode solenoid to provide hydraulic pressure to control the first mode valve and selecting the mode for the second and third mode valves further includes controlling a second mode solenoid to provide hydraulic pressure to control the second and third mode valves.