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.

An electro-hydraulic control system for a multispeed transmission having a plurality of torque-transmitting mechanisms includes a controller for operably controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having pressure control solenoids and trim valves. The system may also include one or more shift valves disposed in fluid communication with the fluid source and being capable of moving between stroked and de-stroked positions. In any given range, only two of the plurality of torque-transmitting mechanisms may be applied. Moreover, three of the plurality of pressure control solenoids are normally high solenoids, and the remaining solenoids are normally low solenoids.

A method for operating a pneumatic actuating system of a transmission. The actuating system has an air reservoir at a first pressure. The reservoir couples an actuating space of the actuating system which is at a second pressure, and the actuating space couples, via control valves, shifting cylinders. When conducting a transmission gearshift, an air mass delivered to the active shifting cylinders via corresponding control valves, and an air mass sum including a nominal air mass in the active cylinders required for accomplishing the gearshift and an actual basic leakage from the activated shifting cylinder are determined. A defect leak in the pneumatic actuating system is recognized, if the air mass delivered to the active shifting cylinders is larger than the air mass sum. If a defect leak is recognized, the control valves coupling the actuating space and the shifting cylinders are shut off for a period of time.

A control device for a vehicle including (i) a power transmission device, (ii) a shift operation device that is to be operated by a driver of the vehicle to an operation position corresponding to a shift position of the power transmission device, and (iii) a switching device for switching the shift position of the power transmission device through actuation of an actuator. The control device is configured, upon occurrence of a momentary interruption of a control-device electric-power source that is supplied with an electric power from a vehicle electric-power source, to not perform an initial position learning process for setting a reference position of the actuator, until a shift switching operation for switching the shift position of the power transmission device is performed by a driver of the vehicle.

A back-up control unit of a back-up power source device executes: a battery failure determination process of determining whether or not a battery failure has been detected by a failure detecting unit; when it is determined that battery failure has been detected in the battery failure determination process, a switching instruction determination process for determining, on the basis of an instruction signal from a monitor circuit, whether or not an instruction to switch to a P range has been made by a user; and when it is determined that a switching instruction has been made in the switching instruction determination process, a shifting instruction process for starting power supply from a back-up power source to a shift control unit and instructing the shift control unit to shift to the P range.

A vehicle control device controls a vehicle control system, which includes a shift range switching system configured to switch a shift range by controlling a drive of a shift actuator, and an electric brake system configured to brake a vehicle by controlling a drive of a brake actuator. The vehicle control device includes a shift control unit and a brake control unit. The shift control unit controls a drive of the shift actuator. The brake control units control a drive of a brake actuator. When the start switch of the vehicle is turned off, the power of the brake control units is turned off after the shift range switching system completes switching to the P range.

A shift-by-wire system includes an actuator, a detent plate, a detent spring, a control unit, and a display device. The control unit includes a first position learning unit, a second position learning unit, and a power-on determination unit. When the power-on determination unit determines that the power on is the post-instantaneous interruption on while the vehicle power is turned on, the first position learning unit learns the first reference position or the second position learning unit learns the second reference position, (i) in a case where the display device still displays the N-range after the target-range determination unit determines the target range to the R-range while the display device displays the N-range or (ii) in a case where the display device displays the N-range after the target-range determination unit determines the target range to the N-range while the display device displays the R-range.

An electro-hydraulic control system for a multispeed transmission having a plurality of torque-transmitting mechanisms includes a controller for operably controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having pressure control solenoids and trim valves. The system may also include one or more shift valves disposed in fluid communication with the fluid source and being capable of moving between stroked and de-stroked positions. In any given range, only two of the plurality of torque-transmitting mechanisms may be applied. Moreover, three of the plurality of pressure control solenoids are normally high solenoids, and the remaining solenoids are normally low solenoids.

Provided are a variator and a transmission controller in an engine-driven vehicle. The transmission controller has an instantaneous interruption recovery control portion configured to, upon a power reset from an instantaneous interruption during running, set a target through transmission ratio and a desired through transmission ratio to a lowest transmission ratio value by initialization and perform recovery control to recover an actual through transmission ratio of the variator to a transmission ratio value for shifting to normal control. The instantaneous interruption recovery control portion is further configured to, upon the power reset from the instantaneous interruption during the running, set a change speed of the target through transmission ratio from the lowest transmission ratio value to the desired through transmission ratio, to be higher than that under the normal control, before a time at which the desired through transmission ratio value deviates from the lowest transmission ratio value.

When hydraulic information is not available for use, a lock mechanism control unit of a transmission's rotating shaft operated by hydraulic pressure sets the shift range to a non-running range and sets a parking lock to an unlocked state if a vehicle is in a running state and rotation speed of a drive unit is equal to or higher than a predetermined value, but sets the shift range to a parking range and sets the parking lock to a locked state if the vehicle is in a non-running state or the rotation speed is lower than the predetermined value.