A line pressure control method for a double clutch transmission (DCT) includes estimating a line pressure, which decreases with stoppage of an electric oil pump, based on a linear regression model using state variables of the DCT that are related to a line pressure change, and driving the electric oil pump when the line pressure estimated based on the linear regression model reaches a predetermined lower limit.

In a vehicle equipped with an engine and a shift control mechanism that switches a shift position by rotating a detent plate with an electric actuator, an electronic control device is an electronic control device including a reference position learning unit that executes a learning of a reference position of the actuator that serves as a reference for switching the shift control mechanism by the actuator when a starting condition that is set in advance is satisfied, and includes a drive wheel rotation suppression unit that suppresses a rotation of a drive wheel of the vehicle while the learning of the reference position is being executed by the reference position learning unit.

The present invention is a hydraulic pressure control device for an automatic transmission that performs a gear shift by switching between engagement and disengagement of a plurality of friction engagement elements and includes solenoid valves, provided corresponding to the friction engagement elements, respectively, that switches between engagement and disengagement of the friction engagement elements by switching between supply and non-supply of hydraulic pressures to the friction engagement elements, and a control device that switches between supply and non-supply of the hydraulic pressures to the friction engagement elements by supplying a predetermined control current to the solenoid valves, in which the control device supplies a fixation preventing current lower than the control current to at least one of the solenoid valves corresponding to the friction engagement elements in a disengagement state of the plurality of friction engagement elements.

A method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle, the hybrid disconnect clutch separating or connecting an internal combustion engine and an electrical motor, including: delivering, to drive wheels of the hybrid vehicle, a torque output by the internal combustion engine and the electrical motor; determining the co-efficient of friction while the disconnect clutch is in a slipping state; operating the disconnect clutch in first and second operating modes, the first mode including an open state of the disconnect clutch and the second mode including a closed state of the disconnect clutch; and increasing the co-efficient of friction for more rapid adjustment of the slipping state only in the transition from the closed state to the opened state.

A transmission changes gears in a MT system, an AT system, and an AMT system wherein unintended transition between an AT mode and a MT mode or between an AMT mode and a MT mode is prevented. A selector in a controller performs a mode selection control such that, when performing transition between the AT mode and the MT mode or between the AMT mode and the MT mode, the driver at least has to operate a mode switching switch while operating a clutch lever in an operation amount not smaller than a predetermined threshold.

A system for a vehicle includes a desired pressure module, a valve actuation module, a filter module, and a capacity detection module. The desired pressure module selectively generates an increase in a desired pressure of hydraulic fluid for a clutch of an automatic transmission. The valve actuation module actuates a solenoid valve based on the desired pressure. The solenoid valve supplies hydraulic fluid to a regulator valve, and the regulator valve supplies hydraulic fluid to the clutch. The filter module filters an acceleration of a shaft of the automatic transmission to generate a filtered acceleration. The capacity detection module indicates whether the clutch reached torque carrying capacity based on the filtered acceleration.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, which are an input-side friction plate and an output-side friction plate, and an actuation system configured to engage the input-side friction plate with the output-side friction plate with a pushing force, the friction plates having a characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases. The device includes a controller configured to control the pushing force so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, and an actuation system configured to engage an input-side friction plate with an output-side friction plate with a pushing force, the friction plates having a negative slope characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases, a rotational difference sensor of the friction engagement element, a separator configured to divide a variation in the detected rotational difference into a high-frequency component that is a vibration component and other low-frequency components, and a controller configured to control a pushing force only for the vibration component of the rotational difference so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

While a vehicle is traveling in an automatic driving mode, an auto-driving oil pressure changing unit makes the engagement pressure of hydraulic oil supplied to a release-side engagement device to be released during a downshift of a stepwise shifting unit, higher than the engagement pressure set during traveling in a manual driving mode, so that retraction of the acceleration due to a drop of drive torque during the downshift is reduced. At this time, an auto-driving rotating machine controller makes drive-side MG2 torque generated from a second rotating machine, larger than that generated during traveling in the manual driving mode, so as to speed up the progress of the downshift, and prevent retraction of the acceleration from being prolonged.

A method for determining an engagement point (X) of a clutch (3). The clutch (3) has first and second clutch sides (3a, 3b), which are rotationally decoupled when the clutch (3) is disengaged/open and which are rotationally coupled when the clutch (3) is engaged/closed. The method includes the steps of disengaging the clutch (3) and then engaging the clutch (3), in order to determine the engagement point (X). During this, the first clutch side (3a) is driven in rotation and the second clutch side (3b) is accelerated, for at least part of the time, by an acceleration device (4). A control device actuates the clutch (3) in order determine the engagement point (X) of the clutch (3), and a computer program product with stored commands, brings about the sequence of the method when the program is operated on a suitable control unit.