One solenoid valve included in a hydraulic pressure control device has at least two functions among the following (1) to (6) functions, (1) switching a state of a two-way clutch, (2) switching a state of a parking lock mechanism, (3) switching the supply of hydraulic pressure to a first brake that is put into an engaged state when a gear stage selected when driving of a vehicle starts is set, (4) controlling a line pressure adjustment valve so that a decrease in a line pressure is prevented when the temperature of a hydraulic fluid is a first predetermined temperature or higher, (5) preventing the occurrence of a creep phenomenon in a neutral range when the temperature of the hydraulic fluid is a second predetermined temperature or lower, and (6) boosting a line pressure by performing switching to another linear solenoid valve when the line pressure adjustment valve has failed.

Operating a clutch assembly of a vehicle drive train, the clutch assembly comprising a clutch with a clutch component that exchanges heat at least indirectly with a medium which is conducted at least partially in the clutch, comprises at least: a) determining an operating point parameter which is representative of a current operating state of the clutch; b) determining a first thermal property parameter of the medium, as a function of the determined operating point parameter; c) determining a second thermal property parameter of the at least one clutch component; d) calculating a component temperature of the at least one clutch component as a function of at least the following three values: a further component temperature of a further clutch component, the first thermal property parameter, and the second thermal property parameter; and e) adapting activation of the clutch as a function of the calculated component temperature.

In order to pre-stage a clutch piston in preparation for clutch engagement, a controller commands a high current to a Casting Integrated Direct Acting Solenoid (CIDAS) valve. This staging is performed in two distinct phases wherein the current is higher in the first phase than in the second phase. Staging the piston in this manner reduces the staging time and reduces the variability of the staging time. The duration of the first phase may be adjusted based on a number of parameters including, the length of a preceding engine off period, the number of clutch applications since the engine off period, a fluid temperature, and a length of time since a preceding engagement of the clutch.

Provided is a clutch control device for a work machine capable of controlling a fan to an appropriate rotational speed. In the clutch control device for the work machine, a controller includes a target fan rotational speed calculation module that calculates a target fan rotational speed for the fan, a clutch characteristic curve storage module that stores a plurality of clutch characteristic curves, a clutch command calculation module that outputs with reference to a clutch characteristic curve a first clutch control signal corresponding to the target fan rotational speed, a feedback control module that output a second clutch control signal based on the difference between the target fan rotational speed and an actual fan rotational speed, and an adder that adds the first clutch control signal and the second clutch control signal to output a third clutch control signal.

A drive force transmission device provided in a vehicle includes a rotating shaft, a gear chamber, a first clutch chamber, a hydraulic oil supplier, an oil reservoir, and an oil temperature sensor. The rotating shaft extends in an axial direction and is rotatable around the axial direction to transmit a drive force to left and right drive wheels of the vehicle. The gear chamber houses a gear via which the drive force is to be transmitted to the rotating shaft. The drive force transmission device has a first side and a second side opposite to the first side with respect to the gear chamber in the axial direction. The first clutch chamber is disposed on the first side and houses a clutch that is to distribute the drive force transmitted from the rotating shaft to the left or right drive wheels.

A shift control device includes: a selector configured to receive operation of selecting a shift range of an automatic transmission and output selection information corresponding to the operation, the automatic transmission being configured to convert and output driving force of an engine; a range switch controller configured to switch the shift range in accordance with the selection information; a parking mechanism configured to bring the automatic transmission into a parking state by locking rotation of the automatic transmission; a clutch configured to turn on/off transmission of driving force; a clutch controller configured to control operation of the clutch in accordance with the selection information; and a delay setter configured to set delay time until driving of the parking pawl starts on the basis of rotation speed difference and oil temperature of the automatic transmission when selection information indicating that the parking range is selected is 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 may be provided for correcting a raw signal supplied by a pressure sensor in an all wheel drive system having a hydraulic pump and a hydraulic fluid. The method may include measuring the raw signal supplied by the pressure sensor, determining when the all wheel drive system is in a state where the hydraulic fluid is at a known pressure determined independently from the pressure sensor, determining a new zero-point offset by comparing the raw signal to a voltage value associated with the known pressure, and creating a corrected voltage signal by adjusting the raw signal based on the new zero-point offset. This corrected voltage signal may be converted into a pressure reading for controlling the all wheel drive system.

According to one embodiment, a current detection circuit (12) includes: a detection resistor (Rs) provided between a solenoid valve (106) and a solenoid driver (11); an amplification unit (121) configured to amplify a detected voltage of the detection resistor (Rs); an AD converter (122) that is driven by a reference voltage (Vref) generated based on a reference current (Iref) and configured to convert an output voltage from the amplification unit (121) into a digital value and output the digital value as a detected current value (D1); and a correction unit configured to perform a correction on the detected current value (D1). The correction unit includes: a temperature sensor (123); a storage unit (125) configured to store information about temperature characteristics of the detected current value (D1) generated due to temperature characteristics of a reference current in each of two or more different temperature regions; and an operation unit configured to apply, to the detected current value (D1), a first correction coefficient calculated based on a detection result of the temperature sensor (123) and information about temperature characteristics of the detected current value (D1) stored in the storage unit (125).

A system of a work vehicle includes an engine, a transmission that includes a hydrostatic unit, and a clutch coupled to the transmission. The system also includes a controller communicatively coupled to the engine, the transmission, and the clutch. The controller, in operation, receives a command to disengage the clutch. The controller, in operation, determines an engine speed of the engine. The controller, in operation, also determines a temperature of hydraulic fluid in the clutch. The controller, in operation, further determines a magnitude and time to limit acceleration of the work vehicle based on the engine speed and the temperature. The controller, in operation, also commands the clutch to disengage. The controller, in operation, further limits the acceleration of the work vehicle using the hydrostatic unit based on the magnitude for the time determined.