A method for learning an upwards friction coefficient of an engine clutch of a hybrid vehicle includes: after the engine clutch is engaged, disengaging, by a controller, the engine clutch which connects an engine with a motor or disconnects the engine from the motor; when the engine clutch is disengaged, comparing, by the controller, a temperature of the engine clutch with a threshold value; and when the temperature of the engine clutch is less than the threshold value, increasing, by the controller, a friction coefficient of the engine clutch up to a certain value.

In a hybrid electric vehicle in which an internal combustion engine and an electric motor/generator are connected via a clutch, the controller performs the following processing before the operation of the internal combustion engine stops in a stationary state of the vehicle while the clutch is engaged. Specifically, it is determined whether or not the clutch can be disengaged within a predetermined time period. If the clutch can be disengaged within a predetermined time period, the clutch is disengaged. If the clutch cannot be disengaged within the predetermined time period, a driving torque of the internal combustion engine is lowered to an engine stoppable torque set in advance while the clutch is engaged. Then, the operation of the internal combustion engine stops. Through this control, it is possible to prevent a vibration sound or an abnormal sound that may be generated when a driver turns off the ignition button.

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 control method of a vehicle includes executing one of a plurality of clutch protection logics according to estimated clutch temperatures by a controller. A control constant is counted according to the executed clutch protection logic by the controller. At least one of a shift pattern and an engine revolutions per minute (RPM) are adjusted based on the counted control constant.

Disclosed is a method for protecting a vehicle clutch, including a check step for checking the mileage of a vehicle and the number of times a clutch wear compensation device is operated; after the check step, a calculation step for calculating a clutch thermal severity level, which indicates the degree of thermal severity of the clutch, based on the mileage and the number of times the wear compensation device is operated; and a control step for controlling at least one of the shifting pattern of the vehicle and engine RPM depending on the clutch thermal severity level, after the calculation step.

In a control device for a limited slip differential that limits a differential operation of front and rear wheels of a four-wheel-drive vehicle having mounted thereon a vehicle behavior control device that controls a braking force, an ECU that controls a torque coupling as the limited slip differential includes: a differential limiting force calculating device that calculates target torque of the torque coupling based on a vehicle traveling state; a differential limiting force correcting device that makes a correction to reduce the target torque based on a command from the vehicle behavior control device; and a thermal load calculating device that calculates a thermal load of the torque coupling. The differential limiting force correcting device limits the correction of the target torque based on the command from the vehicle behavior control device, when the thermal load of the torque coupling is equal to or larger than a predetermined value.

A hybrid drive including a first drive motor coupled by a clutch to a shaft, and a second drive motor coupled rigidly to the shaft. A method for determining the temperature of the clutch in the hybrid drive includes the steps of: determining a temperature of the clutch; determining a temperature of the clutch housing; determining the temperature difference between the clutch and the clutch housing; determining the heat conductivity between the clutch and the clutch housing, wherein the heat conductivity is determined as a function of the rotational speed of the first drive motor and the rotational speed of the second drive motor; determining the heat flow between the clutch and the clutch housing on the basis of the product of the heat conductivity and the temperature difference; and adjusting the ascertained clutch temperature on the basis of the ascertained heat flow.

A controller is employed in a vehicle including an engine, a motor generator, and a hydraulically-driven clutch. The controller includes a CPU that executes: a first starting process that starts, when starting the engine under a condition in which a system shaft torque is less than a shaft torque determination value, combustion in the engine after increasing an engine rotation speed to a motor rotation speed by engaging the clutch; a second starting process that starts, when starting the engine under a condition in which the system shaft torque is greater than or equal to the shaft torque determination value, combustion in the engine after the crankshaft starts to be rotated by engaging the clutch, the combustion being started before the engine rotation speed reaches the motor rotation speed; and a setting process that sets the shaft torque determination value to be larger as an oil temperature becomes lower.

A control method for a vehicle includes steps of calculating, by a controller, a clutch severity index based on a clutch temperature distribution, and adjusting, by the controller, at least one of a shift pattern of the transmission and an engine RPM based on the clutch severity index.

A system for limiting engine torque of a four-wheel-drive motor vehicle, including an actuator that is controlled and configured to distribute the engine torque to the drive wheels, a computer calculating at least one variable characteristic of an operation of the vehicle, and a module for limiting the engine torque. In addition, the limitation system includes a mechanism for deactivating the module for limiting the engine torque according to the variable characteristic of the operation of the engine.