A method for operating a dual clutch transmission of a motor vehicle having a first partial transmission, a second partial transmission, a first clutch assigned to the first partial transmission and a second clutch assigned to the second partial transmission, in which the dual clutch transmission is in a parking lock state in which two gears of one of the partial transmissions are engaged simultaneously. The following steps are carried out to exit the parking lock state: Introducing a torque caused by a drive element of the motor vehicle via the clutch associated with the one partial transmission into the one and/or other partial transmission while the gears of the partial transmission are engaged; and disengaging at least one of the gears of the one partial transmission engaged simultaneously in step a).

A method for operating a dual-clutch transmission having a first partial transmission, a second partial transmission, a first clutch assigned to the first partial transmission, and a second clutch assigned to the second partial transmission, in which the dual-clutch transmission is shifted into a parking lock state. The dual-clutch transmission is shifted into the parking lock state by the following steps: while a first gear of one of the partial transmissions is engaged: carrying out an engagement process provided for engaging a second gear of the one partial transmission; determining that the second gear is not engaged despite the engagement process being carried out; selecting a third gear of the dual-clutch transmission different from the first gear and from the second gear; and engaging the selected third gear such that in the park lock condition, the first gear and the third gear are at least temporarily engaged simultaneously.

A power split and power convergence combined hydro-mechanical hybrid transmission device includes an input member, a power split mechanism, a mechanical transmission mechanism, a power convergence mechanism, an output member, a hydraulic transmission mechanism, a clutch assembly, and a brake assembly. The input member is connected to the power split mechanism, the power convergence mechanism is connected to the output member, and the clutch assembly connects an output end of the power split mechanism to an input end of the mechanical transmission mechanism and an input end of the hydraulic transmission mechanism and connects an input end of the power convergence mechanism to an output end of the mechanical transmission mechanism and an output end of the hydraulic transmission mechanism. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member.

A power split and power convergence combined hydro-mechanical hybrid transmission device includes an input member, a power split mechanism, a mechanical transmission mechanism, a power convergence mechanism, an output member, a hydraulic transmission mechanism, a clutch assembly, and a brake assembly. The input member is connected to the power split mechanism, the power convergence mechanism is connected to the output member, and the clutch assembly connects an output end of the power split mechanism to an input end of the mechanical transmission mechanism and an input end of the hydraulic transmission mechanism and connects an input end of the power convergence mechanism to an output end of the mechanical transmission mechanism and an output end of the hydraulic transmission mechanism. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member.

A work vehicle transmission includes a first transmission mechanism that changes input motive power to any one of multiple speeds, and a second transmission mechanism that changes the motive power changed by the first transmission mechanism to any one of multiple speeds, the number of speeds of the second transmission mechanism being smaller than that of the first transmission mechanism. Multiple speed change multi-disc clutches of the first transmission mechanism are arranged parallel with multiple deceleration multi-disc clutches of the second transmission mechanism so as to be adjacent in the diameter direction thereof.

A vehicular power transmitting system including a power transmitting member, an oil pump, and an oil piping assembly, and the oil piping assembly includes an oil piping body having an oil inlet and fixed, and a branch pipe. The branch pipe has a width direction parallel to a longitudinal direction of the oil piping body, and includes proximal and distal end portions. The proximal end portion is connected to the oil piping body, and the distal end portion has a delivery nozzle from which the oil is delivered toward the lubricated portion. The branch pipe has an opening formed in the proximal end portion, for communication of the branch pipe with the oil piping body, the opening having a dimension in a width direction of the branch pipe, which dimension is larger than a dimension of the distal end portion in the width direction of the branch pipe.

The disclosure provides a hydraulic control device capable of suppressing an excessive increase in the rotation speed of a second pump and stabilizing the discharge pressure of the second pump. The target rotation speed of the second pump for making a pressure value of a first oil close to an estimated value of a pressure value of a third oil is calculated, and a feedback amount with respect to the target rotation speed is calculated by subtracting the estimated value of the pressure value of the third oil from the pressure value of the first oil detected by a hydraulic sensor. Time regions for performing calculation of the feedback amount include an update region in which the feedback amount with respect to the target rotation speed is updated, and a hold region in which update of the feedback amount with respect to the target rotation speed is temporarily stopped.

A hydraulic pressure control method for a vehicle transmission includes accumulating factors representing vehicle usage, accumulating factors representing driver's driving tendency, calculating a first line pressure compensation value according to the usage depending on the accumulated values of the factors representing the vehicle usage, calculating a second line pressure compensation value according to the driver's driving tendency depending on the accumulated values of the factors representing the driver's driving tendency, determining a final line pressure by adding the first and second line pressure compensation values according to the usage and the driver's driving tendency to a basic line pressure, and operating a transmission hydraulic system according to the final line pressure.

A hydraulic system for a vehicle transmission with at least two friction elements, the system comprising a first hydraulic circuit comprising a pump for supplying hydraulic fluid to the first hydraulic circuit. A flow restriction may be provided in the first hydraulic circuit between an output of the pump and a sump for providing leakage of hydraulic fluid into the sump. Further, a second hydraulic circuit comprising a second pump may be arranged, wherein the hydraulic pressure in the first circuit is higher compared to the second circuit. A flow control element operated using hydraulic pressure from the first circuit may be arranged for controlling flow/pressure in the second circuit. Further, the hydraulic system may be arranged for generating a line pressure, wherein an actuator for engaging a park lock system may be connected to the first hydraulic circuit for enabling direct actuation by means of the line pressure.

Vehicles and related systems and methods are provided for round-robin air purging of disengaged clutches. One method involves obtaining a plurality of weighting factors associated with respective ones of a plurality of clutches of a vehicle transmission, obtaining an exhaustion time associated with each respective clutch, determining a respective priority metric associated with the each respective clutch based at least in part on the exhaustion time associated with the respective clutch and the respective weighting factor associated with the respective clutch, determining a highest priority clutch of the plurality of clutches based at least in part on the respective priority metrics associated with the respective clutches of the plurality of clutches, and operating one or more valves in accordance with a pulse command to pulse the highest priority clutch with a commanded pressure for a commanded period of time.