In ore aspect, a method is provided or braking a work vehicle including an engine and a hydrostatic drive system including a hydraulic pump configured to be rotationally driven by the engine and a hydraulic motor fluidly coupled with the hydraulic pump through a closed hydraulic loop of the hydrostatic drive system. The hydraulic pump may be configured to fluidly drive the hydraulic motor. The method may include receiving an operator request to reduce a ground speed of the work vehicle. The method may include monitoring a fluid temperature of a hydraulic fluid associated with the closed hydraulic loop and automatically controlling at least one of a pump displacement of the hydraulic pump or a motor displacement of the hydraulic motor based on the operator request and the monitored fluid temperature to adjust hydrostatic braking of the work vehicle and thereby reduce the ground speed of the work vehicle.

A hybrid vehicle includes an engine, an electric machine, a disconnect clutch configured to selectively couple the engine to the electric machine, and a controller. The controller is programmed to, in response to a request to start the engine with the electric machine, command a target pressure to the disconnect clutch that depends on a seal friction derived from a measured line pressure of the disconnect clutch and a rate change of the measured line pressure.

A hybrid vehicle system includes: an engine that is capable of outputting a torque to be transmitted to a driving wheel; a first motor generator that is provided in a coupled manner to the engine and that is capable of outputting a torque to be transmitted to the driving wheel; a transmission that converts a torque output from one or both of the engine and the first motor generator at a predetermined transmission gear ratio; a transmission clutch that is capable of switching on and off power transmission between the first motor generator and the transmission; a second motor generator that is capable of outputting a torque to be transmitted to the driving wheel in a state where the transmission clutch is disengaged; and an oil pump that is coupled to a motor shaft of the first motor generator and that is driven by rotation of the motor shaft.

Provided is a control device for a vehicle including a continuously variable transmission. The control device includes a lock-up clutch, an oil pump, an electric motor, and a device control unit. The lock-up clutch is disposed in a torque converter coupled to the engine and switchable between an engaged state and a released state. The oil pump is driven by the engine and supplies a hydraulic oil to the continuously variable transmission. The electric motor is coupled to the engine and controlled to be in a powering state in which the engine is rotationally driven. The device control unit controls the lock-up clutch to put into the released state and controls the electric motor to put into the powering state if a discharge pressure of the oil pump falls below a threshold value at the time of a vehicle deceleration in which a fuel supply to the engine is cut off.

Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, torque capacity of a driveline disconnect is adjusted in response to a change in commanded line pressure. The torque capacity of the driveline disconnect clutch may be adjusted in according to a maximum transmission line pressure.

A transmission is subject to thermal management to prevent damage or failure due to overheating. Sensors can be employed to capture characteristics of a transmission, such as fluid temperature or pressure. Further, a predictive model can be invoked to predict characteristics based on current and future conditions. Characteristics can be compared with a threshold for intervention. A thermal mitigation strategy can be generated and initiated when characteristics satisfy the threshold. The thermal mitigation strategy can specify various actions to dissipate heat, including altering shift control logic and triggering mechanical devices that can increase airflow, reduce air temperature, or both surrounding the transmission.

A method and system for controlling an engine clutch of a P2 type parallel hybrid vehicle includes steps of: determining whether or not a learning mode entry condition is satisfied, depending on whether or not a kickdown shift occurs during performance of variable hydraulic control of an engine clutch and based on the degree to which slip of the engine clutch occurs, deriving and storing a learning hydraulic value for suppressing the slip that is to occur when the kickdown shift occurs during the performance of the variable hydraulic control in such a manner that the slip does not occur, when a vehicle state satisfies a predetermined learning mode entry condition, and computing a final hydraulic pressure by adding a hydraulic compensation value to a target hydraulic pressure, when the same kickdown shift situation occurs, and controlling the engine clutch using the computed final hydraulic pressure.

A temperature estimation device for friction engaging elements including an execution device and a storage device is provided. The storage device stores mapping data that defines mapping. The mapping includes, as an input variable, a heat amount variable that is a variable indicating an amount of heat generated by the friction engaging elements during the shifting of the transmission and a shifting variable indicating the friction engaging elements to be engaged at the time of the shifting of the transmission, and, as an output variable, the temperature. The execution device executes an acquisition process of acquiring a value of the input variable and a calculation process of inputting the value of the input variable acquired by the acquisition process into the mapping to calculate a value of the output variable.

An apparatus including a transmission mechanism in a power transfer path between a drive source and wheels; an oil pressure control device supplying lubricating oil to the transmission mechanism; and a control part outputting an electrical instruction to increase a flow rate of the supplied lubricating. When the control part outputs an electrical instruction to the oil pressure control device to increase a flow rate of lubricating oil supplied to the transmission mechanism, and determines that the flow rate of lubricating oil supplied to the transmission mechanism from the oil pressure control device does not increase as indicated by the electrical instruction (time t1), the control part considers that the oil pressure control device is in an abnormal state, and can impose a limitation that an absolute value of torque of the transmission mechanism transferred between the wheels and the drive source be reduced (time t1-t5).

A hybrid vehicle includes an engine, a switching valve, and an electronic control unit. The electronic control unit configured to perform switching from the engine travel mode to the EV travel mode through a first stage to start the filling control when it is determined that the possibility is high that the engine stop condition will be established afterwards while the engine travel mode is selected, a second stage to start the clutch release control by switching the switching valve to the second state in response to establishment of the engine stop condition, and a third stage to stop operation of the engine after completion of the clutch release control.