A hydraulic control device for a vehicle is provided wherein a determination of “base neutral” is made when a difference between a command hydraulic pressure and an actual hydraulic pressure of a hydraulic clutch is within a predetermined minute value range, and when the difference is out of the minute value range, a determination of “base raising” is made if the command hydraulic pressure is larger than the actual hydraulic pressure, and a determination of “base lowering” is made if the command hydraulic pressure is smaller than the actual hydraulic pressure. The determination of “sub raising” is made when an inclination of command torque subjected to low-pass filter processing is positive for a predetermined time or more, and the determination of “sub lowering” is made when the inclination is negative for the predetermined time or more, whereby a rising or dropping tendency of the command torque is determined.

A method for automatically warming up a clutch actuator for a clutch of a transmission in a vehicle, wherein the clutch actuator is operable by use of pressurized fluid and configured to actuate the clutch from an engaged to a disengaged state, and/or vice versa, the method including: identifying if a temperature is below a predetermined temperature value and if the clutch actuator is leaking, and if it is identified that the temperature is below the predetermined temperature value and that the clutch actuator is leaking; then repeatedly pressurizing the clutch actuator by use of the pressurized fluid until a state is reached indicative of the clutch actuator being functional, or until a maximum run out state is reached indicative of a faulty clutch actuator.

Methods and systems are provided for sensing a clutch position. In one example, a method may include generating a single output signal by combining at least an output of a first sensor and an output of a second sensor output, the first sensor and second sensor connected in parallel, and the first sensor and the second sensor sensing a common moving element of a clutch. In one example, the method may further include a first sensor output and a second sensor output provided on a common sensor bus. As another example, the first sensor output may be a master pulse width modulation output, and the second sensor output follows a modulation frequency of the first sensor output.

A method for controlling clutch pressure in an electronically controlled limited slip differential comprises receiving a target clutch pressure command indicative of a desired differential torque transfer setting. Processing the target clutch pressure command comprises estimating one of a motor current or a motor speed, calculating an integrated error of a target motor current or an integrated error of a target motor speed, calculating gains over time based on the estimated motor current or the estimated motor speed and based on the integrated error of the target motor current or the integrated error of the target motor speed, applying the calculated gains thereby forming a closed loop feedback, and calculating an oscillation. The target motor current or the target motor speed is applied to a motor connected to a clutch in the differential according to the calculated oscillation to control the clutch pressure of the differential.

A method of controlling the electric current of a linear solenoid valve by performing pulse width modulation on a coil current for energizing a linear solenoid of the linear solenoid valve to adjust the hydraulic pressure of a working oil in a hydraulic clutch for transmitting and interrupting the rotational drive power from a power source to a drive wheel of a vehicle. The method includes setting the period of the pulse width modulation to a shorter value as the degree to which the hydraulic clutch is engaged increases from a disengaged state thereof. Here, the period of the pulse width modulation may be set in accordance with the variation of a duty ratio depending on the hydraulic pressure corresponding to the degree to which the hydraulic clutch is engaged.

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.

The invention relates to a method for determining and/or controlling a position of an electric motor, in particular in a clutch actuation system of a motor vehicle, wherein the position of a rotor of the electric motor is picked up by a sensor system situated on a stator of the electric motor outside an axis of rotation of the electric motor, and the position signal picked up by the sensor system is analyzed by an analysis unit. In a method in which the rotor position is detected with a high level of certainty, the position signal is transmitted to the analysis unit depending on a transmission distance between the sensor system and the analysis unit by means of an SPI protocol signal for short transmission distances, and/or by means of a PWM signal for longer transmission distances.

A method for automatically warming up a clutch actuator for a clutch of a transmission in a vehicle, wherein the clutch actuator is operable by use of pressurized fluid and configured to actuate the clutch from an engaged to a disengaged state, and/or vice versa, the method including: identifying if a temperature is below a predetermined temperature value and if the clutch actuator is leaking, and if it is identified that the temperature is below the predetermined temperature value and that the clutch actuator is leaking; then repeatedly pressurizing the clutch actuator by use of the pressurized fluid until a state is reached indicative of the clutch actuator being functional, or until a maximum run out state is reached indicative of a faulty clutch actuator.

A controller executes a dither control that cyclically increases and decreases an exciting current in a linear solenoid valve so as to vibrate a spool of the linear solenoid valve. A vibration cycle of the spool obtained through the dither control is referred to a dither cycle. The dither control includes a first dither control that vibrates the spool in a first dither cycle and a second dither control that vibrates the spool in a second dither cycle that is shorter than the first dither cycle. The controller executes the first dither control and the second dither control when an oil temperature of the hydraulic oil is between a first oil temperature and a second oil temperature that is higher than the first oil temperature.

A controller executes a dither control that cyclically increases and decreases an exciting current in a linear solenoid valve so as to vibrate a spool of the linear solenoid valve. A vibration cycle of the spool obtained through the dither control is referred to a dither cycle. The dither control includes a first dither control that vibrates the spool in a first dither cycle and a second dither control that vibrates the spool in a second dither cycle that is shorter than the first dither cycle. The controller executes the first dither control and the second dither control when an oil temperature of the hydraulic oil is between a first oil temperature and a second oil temperature that is higher than the first oil temperature.