A vehicle drive device includes a control device, and the control device controls an electric motor, a first pressing mechanism and a second pressing mechanism such that a relational expression of T<T.sub.1+T.sub.2 is satisfied, where T represents a torque that is input to an input rotation member, T.sub.1 represents a maximum of a torque that is able to be transmitted by a first multi-disc clutch and T.sub.2 represents a maximum of a torque that is able to be transmitted by a second multi-disc clutch.

A vehicle drive device includes a control device, and the control device controls an electric motor, a first pressing mechanism and a second pressing mechanism such that a relational expression of T<T.sub.1+T.sub.2 is satisfied, where T represents a torque that is input to an input rotation member, T.sub.1 represents a maximum of a torque that is able to be transmitted by a first multi-disc clutch and T.sub.2 represents a maximum of a torque that is able to be transmitted by a second multi-disc clutch.

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.

A system and method for controlling engine clutch slip for a hybrid vehicle, in which it is determined whether an engine clutch has entered a slip mode and lubrication of the engine clutch is easily achieved through an additional lubrication hydraulic pressure circuit whenever the engine clutch enters the slip mode, thereby achieving the engine clutch slip control in all shift ranges including low-speed and medium-speed ranges and maintaining the heat energy that is generated from the engine clutch at a predetermined level or lower.

A driving-force transmitting apparatus includes first and second friction clutches, a piston that presses the first and second friction clutches, a hydraulic pump that feeds hydraulic oil to a cylinder chamber in the piston, an electric motor that drives the hydraulic pump, and a control apparatus that controls the electric motor to adjust the discharge pressure of the hydraulic pump. The control apparatus has a feedback control apparatus that controls the electric motor using a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump, a hydraulic-oil temperature estimating apparatus that estimates a temperature of hydraulic oil, and a gain adjusting apparatus that changes a correction amount for feedback control in accordance with the estimated temperature of the hydraulic oil.

A system and method for controlling engine clutch slip for a hybrid vehicle, in which it is determined whether an engine clutch has entered a slip mode and lubrication of the engine clutch is easily achieved through an additional lubrication hydraulic pressure circuit whenever the engine clutch enters the slip mode, thereby achieving the engine clutch slip control in all shift ranges including low-speed and medium-speed ranges and maintaining the heat energy that is generated from the engine clutch at a predetermined level or lower.

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 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.

A method for controlling a clutch includes judging whether or not a slip amount of the clutch is reduced to below a first reference value by a controller after starting of the vehicle is launched, judging whether or not accumulated slip energy of the clutch until a present time from the launch of starting the vehicle is a second reference value or more, as a result of judgment as to the slip amount of the clutch, if the slip amount of the clutch is below the first reference value, and controlling engagement of the clutch so as to prevent overheating of the clutch while the controller causes an engine to maintain a target engine speed, as a result of the judgment as to the accumulated slip energy, if the accumulated slip energy is the second reference value or more.

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.