A method for the control of a hydraulic system of a motor vehicle is provided. A high-pressure branch is fed by a main oil pump which is driven by an internal combustion engine. The high-pressure branch or a low-pressure branch is fed by an additional oil pump depending on a switch position of a switching valve. The additional oil pump is used for feeding the high-pressure branch or the low-pressure branch depending on a total volume flow demand and on the volume flow available from the main oil pump. A nominal rotation speed of an electric motor which drives the additional oil pump is determined based on a volume flow balance, a valve status of the switching valve, a low-pressure pump map or a high-pressure pump map. Depending on the valve status, either the low-pressure pump map or the high-pressure pump map is used to determine the nominal rotation speed.

The present invention discloses a dual-clutch automatic transmission cooling and lubrication hydraulic control system and a vehicle. The dual-clutch automatic transmission cooling and lubrication hydraulic control system comprises a clutch lubrication control valve whose outlet end is connected with a clutch lubricating oil circuit, a gear lubrication control valve whose outlet end is connected with a gear and bearing lubricating oil circuit, the inlet end of the gear lubrication control valve being connected with the inlet end of the clutch lubrication control valve in parallel at the first common end, further comprises a mechanical pump and an electronic pump whose inlet ends are connected to an oil tank respectively. The outlet end of the mechanical pump and the outlet end of the electronic pump are connected in the second common end in parallel, and a cooler disposed between the first common end and the second common end. The dual-clutch automatic transmission cooling and lubrication hydraulic control system disclosed herein have a variety of working modes, reducing the defects such as large displacement of the mechanical pump when working alone.

A driving system includes an engine an engine, a motor generator, a gear mechanism, and a controller. The gear mechanism couples the engine and the motor generator to each other. The gear mechanism includes first and second gears. The first and second gears are configured to be supplied with first driving torque from the engine and second driving torque from the motor generator, respectively. The second gear meshes with the first gear. The controller is configured to perform torque control of the engine to make a rate of variation in the first driving torque at the first gear at a time when the following conditional expression (1) is satisfied smaller than that at a time when the following conditional expression (1) is not satisfied.
|T2−T1|<Th1  (1) T1 is the first driving torque, T2 is the second driving torque, and Th1 is a first threshold.

The present invention relates to an exchangeable milling drum box for a ground milling machine, particularly for a road milling machine, a recycler, a stabilizer or a surface miner, with a milling drum rotatably mounted in the exchangeable milling drum box and a transmission, via which the milling drum can be driven, the transmission comprising a lubrication device with a lubricant, and the exchangeable milling drum box comprising a cooling and/or heating device for lubricant. Furthermore, the present invention relates to a ground milling machine having such an exchangeable milling drum box. The present invention also relates to a method for cooling and/or heating lubricant of a transmission of a milling drum mounted rotatably in an exchangeable milling drum box of a ground milling machine, the method comprising the steps: Supplying cooling and/or a heating medium from the ground milling machine to the lubricant located in a lubrication device arranged on the exchangeable milling drum box; cooling and/or heating the lubricant through heat transfer between the coolant and/or heating medium and the lubricant; and discharging the cooling and/or heating medium from the exchangeable milling drum box to the ground milling machine.

A hydraulic arrangement for a vehicle transmission includes a hydraulic system path leading to a hydraulic system circuit with a system pressure, a hydraulic lubrication path leading to a hydraulic lubrication circuit with a lubrication pressure, and a branching point connected to an output side of the system and lubrication paths. A variable displacement pump or a pump combination includes at least two fixed displacement pumps hydraulically connected to an input side of the branching point, and a variable displacement pump or at least one fixed displacement pump are hydraulically connected to the output side of the branching point and integrated into the hydraulic system path.

A valve includes a valve housing, a piston, a support element, and a spring. The piston and the valve housing are arranged coaxially to each other on an imaginary valve axis. The piston is received in the valve housing in an axially movable manner against the spring force of the spring. The spring is supported on the support element and on the piston. The valve housing is provided with a first opening through which a fluid can flow and which can be closed by a piston base of the piston. The valve housing is provided with a second opening which can be at least partly closed by a piston casing of the piston and through which the fluid can flow. The piston casing extends outwards from the piston base in the axial direction of the support element and surrounds the valve axis.

A dual clutch transmission comprises a housing formed therein with a gear chamber incorporating an odd-numbered speed gear train group and an even-numbered speed gear train group. An end of the input shaft is connected to an engine, and a cover is detachably attached to the housing opposite the end of the input shaft so as to define a clutch chamber divided from the gear chamber. A first clutch for the odd-numbered speed gear train group and a second clutch for the even-numbered speed gear train group are disposed in the clutch chamber. Fluid passages for supplying hydraulic fluid to the first and second clutches are formed in the cover.

An electric oil pump control method for operating a transmission of a hybrid vehicle which is driven by a first motor, a second motor, and an engine is provided. The method includes determining a number of revolutions of a low-pressure pump of an electric oil pump based on lubrication flow amount of the first motor, lubrication flow amount of the second motor, cooling flow amount of the first motor, and cooling flow amount of the second motor and determining a number of revolutions of a high-pressure pump of the electric oil pump based on control flow amount of a clutch of the transmission and lubrication flow amount of a rotation driver included in the transmission. A maximum value is determined of the determined number of revolutions of the low-pressure pump and the determined number of revolutions of the high-pressure pump as a number of revolutions of the electric oil pump.

A power transmission device for a hybrid vehicle has a first clutch device (1a) disposed in a drivetrain between an engine (E) and a driving wheel (D). A second clutch device (1b) disposed in a drivetrain extends from a motor (M) to the driving wheel (D). The oil pump (P), connected to the motor (M), supplies oil to a predetermined moving component disposed in the vehicle by using driving power of the motor (M). A transmission (A) is disposed in a drivetrain between the engine (E) and the motor (M) and the driving wheel (D). The transmission adjusts rotation speed of the motor (M). The power transmission device supplying oil by causing the motor (M) to rotate the oil pump (P) at an appropriate rotation speed.

A motor vehicle vacuum driven hydraulic balance system includes a housing. A shaft rotatably supported in the housing has a longitudinal bore to deliver oil flow to a plurality of ports created in the shaft. A vacuum flow passage communicates with both the longitudinal bore and an oil sump. A first delivery passage is created in a portion of the housing, the first delivery passage in direct communication with the longitudinal bore. An electrical oil pump pumps oil from the oil sump to the longitudinal bore through the first delivery passage. Axial rotation of the shaft creates a partial vacuum in the longitudinal bore acting to vacuum drag oil from the oil sump through the vacuum flow passage to the longitudinal bore in addition to a volume of the oil delivered to the longitudinal bore by the electrical oil pump.