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.

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 hydrostatic travel drive includes a hydraulic pump for the purpose of supplying pressure medium to a hydraulic motor of the travel drive that can be coupled to an output, which pump can be coupled to a drive machine. The hydraulic pump has an actuating cylinder with at least one cylinder chamber and a swept volume which can be adjusted via the actuating cylinder, and at least one electrically activatable pressure valve via which the cylinder chamber can be charged with an adjustingly active actuating pressure. The travel drive further includes device via which a pressure of the hydraulic pump can be limited by means of influencing the actuating pressure.

A hydrostatic travel drive includes a hydraulic pump for the purpose of supplying pressure medium to a hydraulic motor of the travel drive that can be coupled to an output, which pump can be coupled to a drive machine. The hydraulic pump has an actuating cylinder with at least one cylinder chamber and a swept volume which can be adjusted via the actuating cylinder, and at least one electrically activatable pressure valve via which the cylinder chamber can be charged with an adjustingly active actuating pressure. The travel drive further includes device via which a pressure of the hydraulic pump can be limited by means of influencing the actuating pressure.

A travel control device is provided with hydraulic pumps of a variable capacity type that are driven by an engine; hydraulic motors that are driven by discharged oil from the hydraulic pumps; traveling devices that are rotation-driven by the hydraulic motors; a travel operation lever that is operated so as to instruct a traveling operation; a first control valve for generating a charged hydraulic pressure by adjusting the discharged oil from a charge pump and a second control valve for generating a capacity control hydraulic pressure in accordance with the operation of the travel operation lever. The first control valve is designed to pressure-adjust and generate a charged hydraulic pressure in accordance with the rotation speed of the engine, and the hydraulic pump is subjected to a variable capacity control process by a capacity control hydraulic pressure that is pressure-adjusted and generated by the second control valve.

The present invention relates to a system for assisting the driving of a vehicle comprising at least one hydraulic machine forming a pump (19), at least one hydraulic machine forming an engine (130, 140) and an open hydraulic circuit (100) extending through a tank (13) and comprising a suction duct (11) extending from the tank (13) to an inlet of the pump (19), a supply duct (15) extending from the outlet of the pump (19) to the inlet of the engine (130, 140) and a return duct (122) extending from the outlet of the engines (130, 140) to the tank (13), characterised in that at least one of the engines (130, 140) is an engine that can disengage the clutch, and in that the system comprises an element forming a restriction (180) and creating a loss of charge over the return duct and a means (190, 192) adapted for connecting to the engine casing, the part of the return duct (122) located upstream of the element forming a restriction (180) and for applying to the engine casing, from the return duct (122), a pressure lower than the pressure of this return duct.

The present invention relates to a system for assisting the driving of a vehicle comprising at least one hydraulic machine forming a pump (19), at least one hydraulic machine forming an engine (130, 140) and an open hydraulic circuit (100) extending through a tank (13) and comprising a suction duct (11) extending from the tank (13) to an inlet of the pump (19), a supply duct (15) extending from the outlet of the pump (19) to the inlet of the engine (130, 140) and a return duct (122) extending from the outlet of the engines (130, 140) to the tank (13), characterised in that at least one of the engines (130, 140) is an engine that can disengage the clutch, and in that the system comprises an element forming a restriction (180) and creating a loss of charge over the return duct and a means (190, 192) adapted for connecting to the engine casing, the part of the return duct (122) located upstream of the element forming a restriction (180) and for applying to the engine casing, from the return duct (122), a pressure lower than the pressure of this return duct.

A hydraulic system in a work machine includes a travel operation device provided in a pilot oil path between a hydraulic pump a travel pump and including an operation member and configured to generate a pilot pressure supplied via the pilot oil path and an additional pilot pressure in accordance with an operation amount of the operation member. The travel pump is to control a flow direction of hydraulic oil supplied to a travel motor based on the pilot pressure and the additional pilot pressure. A pressure selection valve is provided in a first coupling oil path to select a selected pressure from the pilot pressure and the additional pilot pressure to apply the selected pressure to the pilot hydraulic oil in the second coupling oil path. A pressure adjustment valve is provided in a second coupling oil path to control the selected pressure to be an adjusted pilot pressure.

A hydraulic system in a work machine includes a hydraulic pump to supply pilot hydraulic oil. A work hydraulic actuator is to move a work device of the work machine. A control valve is to control the work hydraulic actuator based on a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through the work operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the control valve. A pilot oil path connects the work operation device and the control valve to supply the pilot pressure to the control valve. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.

A hydrodynamic clutch having an input side and an output side, the rotational motions of which are coupled to one another with a hydraulic fluid. A method for determining the degree of filling of the hydrodynamic clutch with fluid including steps of periodically sensing a fluid temperature of the hydraulic fluid, determining the thermal output supplied to the clutch on the basis of the temperature, determining a lambda value on the basis of the thermal output and determining the degree of filling on the basis of the lambda value.