Abstract: Disclosed is a viscous coupling that has a housing that carries ribs that are arranged concentrically about a central axis. A rotor is provided that can rotate relative to the housing about the central axis in a predetermined direction. The rotor also carries ribs, and the ribs of the housing and the rotor are arranged in a working chamber surrounded by the housing. Also provided is a fluid reservoir. A fluid discharge line leads from the working chamber to the fluid reservoir. A wiper is moveably arranged between the housing and the rotor and scrapes fluid from the rotor and feeds it to the fluid discharge line. A stop is provided for the wiper and is arranged next to the rotor.

Abstract: A valve system (44) for reducing morning sickness effects in a viscous clutch (20) having a reservoir (38) with a bore (46-1) includes a valve element (44-1), a counterweight portion (44-2), a pivot (44-3), and a biasing member (44-4). The pivot is located in between the valve element and the counterweight portion, and the valve element and the counterweight portion are configured to commonly move about the pivot between open and closed positions. The biasing member is configured to bias the valve element to cover the bore in the closed position by default. The counterweight portion is configured to counteract the biasing member under centrifugal loading such that the valve element at least partially uncovers the bore in the open position.

Abstract: Disclosed is an exemplary hydraulic system including a first fluid circuit and a first pump fluidly connected to the first fluid circuit. The first pump configured to produce a fluid output at a first flow rate when operated at a selected speed. The hydraulic system further includes a second fluid circuit and a second pump selectively fluidly connectable to the first fluid circuit and the second fluid circuit. The second pump configured to produce a fluid output at a second flow rate when operated at the selected speed, with the second flow rate being greater than the first flow rate of the first pump. A first valve fluidly connects the second pump to the first fluid circuit when the first valve is arranged in an open position, and fluidly connects the second pump to second fluid circuit when the first valve is arranged in a closed position.

Abstract: A method for activating a clutch of a vehicle drive train. A controller of an electronic control unit generates an electrical desired-value signal corresponding to a desired pressure with which the clutch is to be acted upon. The control unit receives from a sensor an electrical actual-value signal which is to correspond to an actual pressure with which the clutch is acted upon. The sensor measures the pressure at a measurement location which is connected via a transfer link to an action location at which the clutch is acted upon with a clutch pressure. The actual-value signal passes through a transfer element having a delay property before it is delivered to the controller.

Abstract: Accordingly, a control system for controlling a viscous clutch of a fan is provided. The control system includes a delta speed module that determines one of an over speed condition, an under speed condition, and a steady state condition based on a desired fan speed and an actual fan speed. A mode module determines a mode of the clutch based on the one of the over-speed condition, the under-speed condition, and the steady state condition, wherein the mode is one of a pump in mode, a pump out mode, and a closed loop mode. A valve control module that controls an operational state of the clutch valve based on the mode.

Abstract: A viscous fluid clutch for controlling the rotation of an engine cooling fan has a dividing disk separating a storage chamber from a working chamber. The dividing disk includes an opening having a geometry that defines a drain-back path to the working chamber regardless of the angular orientation of the clutch.

Abstract: A double clutch of a double clutch transmission of an engine is shown and described, and can comprise two clutch packs associated to two coaxial shafts, two clutch pistons each activating one of the clutch packs, and a hydraulic control device including a low pressure pump for lubrication and cooling of the clutch plates of the clutch packs, and a high pressure pump for activation of the clutch piston and a synchronizer. The low pressure pump and the high pressure pump can be disposed in parallel. Also, an electronic control device can control the hydraulic control system. In some embodiments, a flow switch is provided in a low engine speed range, and is adapted to combine oil flow of the low pressure pump and the high pressure pump at high pressures.

Abstract: The present invention provides a method and apparatus for controlling the pressure of an actuating fluid flowing through an inching clutch. The invention includes the steps of determining an actual pressure of the actuating fluid, establishing an inching pressure threshold, comparing the actual pressure with the threshold, and controlling the actual pressure in response to the comparison. In one embodiment, the pressure is controlled using a first control algorithm in response to the fluid pressure being less than an inching threshold, and using a second control algorithm in response to the pressure being greater than or equal to the inching threshold.