Abstract: A master clutch includes a pressure plate adjacent to a friction disc. A centrifugal weight forces the pressure plate and friction disc into engagement when in a desired install position. A locking device retains the centrifugal weight in the desired installed position. A controller sends an electronic command to a system component, such as an engine, to disengage the locking device. In one example, the electronic command may be an engine speed command that is above an engine speed limit in a normal vehicle operating mode. Commanding the engine to run at a speed greater than the typical engine speed limit moves the centrifugal weight out of the desired installed position making the master clutch operational.

Abstract: A clutch assembly includes a reaction surface that provides several disengagement surfaces that cause axial movement of a front plate to reduce torque transmission at rotational speeds above an engagement speed. The disengagement surfaces reduce torque to break torque lock at rotational speeds corresponding to desired gear changes. The clutch assembly is controlled to tailor the relationship between clutch torque and engine speed to current vehicle operating conditions to provide consistent vehicle performance over different operating conditions.

Abstract: A vehicle power train system includes an engine, a transmission, and a centrifugal clutch assembly that selectively couples an engine output shaft to a transmission input shaft in response to an operator input. An operator selects a desired vehicle-operating mode by actuating a shift lever or shift switch from a gear selection device. The gear selection device indicates many different operating modes and includes a low-speed maneuvering mode that is selected for low-speed operations such as coupling a truck to a trailer, or positioning a truck and/or trailer in relation to a loading dock area. Once the low-speed maneuvering mode is selected, a control unit controls at least one of engine speed and engine torque to indirectly effect clutch slippage, which results in improved vehicle speed control at low-speed operations.

Abstract: A centrifugal clutch assembly includes a clutch cover attachable to a rotatable input member. Friction plates are clamped between pressure plates in response to rotation of the clutch assembly. Rotation of the clutch assembly causes at least one centrifugal weight to move radially outward to force the pressure plates against the friction plates. The radial position of the centrifugal weights is modified to tailor clutch actuation. This modification of centrifugal weight position causes a corresponding change to engagement characteristics of the clutch assembly allowing clutch actuation to be tailored to operating conditions.

Abstract: An inertia brake assembly for a transmission includes a hollow shaft rotatable relative to an input shaft of the transmission. An inertia brake housing is rotatable relative to the input shaft and the hollow shaft. A first clutch assembly couples the hollow shaft to the inertia brake housing. A second clutch assembly couples the input shaft to the inertia brake housing and a retarder assembly couples the inertia brake housing to the transmission housing. Selective actuation of a combination of the various clutch assemblies provides the functions of an inertia brake, engine brake, hill holder, master clutch and drive a power take-off assembly.

Abstract: A clutch assembly controller monitors initiation points for torque transfer and clutch lockup to determine a clutch engagement rate. Engine output shaft and transmission input shaft speeds are monitored to determine the points at which the torque transfer and clutch lockup begin. These points are stored as reference points and are updated as the clutch wears over time. The clutch engagement rate is also modified over time as the reference points change. Further, the controller utilizes the reference points to approach the desired clutch engagement and disengagement points at a higher rate of speed to optimize responsiveness while automatically changing to a lower rate of speed once operating in the desired region of interest to optimize clutch operating performance and comfort.

Abstract: A centrifugal clutch assembly includes movable centrifugal weight reaction surfaces that provide for actuation at varying rotational speeds. A radially movable front plate with a ramped surface changes the radial position at which the centrifugal weight begins moving the front plate axially to compress a clamp spring and begin clutch actuation. An axially movable back plate moves axially to change the magnitude of compression caused by axial movement of the front plate. The changes to clamping force corresponding to movement of the reaction surfaces of the centrifugal weight change the rotational speed required to beginning and maintain actuation of the clutch assembly.

Abstract: A transmission system which relates the relative movement of vehicle components to determine the onset of zero relative torque to permit a shift change to be effected at approximately zero relative torque. When a predetermined signature is identified which relates to the onset of zero relative torque the transmission shift controller initiates a shift.

Abstract: A vehicle transmission system includes a transmission component that has an engaged condition where torque can be transferred from a vehicle engine to a drive component, and a non-engaged condition where torque is prohibited from being transferred to the drive component. A controller generates control signals to control whether the transmission component is in the engaged or non-engaged condition. The controller also identifies when a vehicle start maneuver is a coast start based on vehicle conditions existing just prior to or during the vehicle start maneuver. When a coast start is identified, the controller generates a control signal to either disengage the transmission component or to maintain the transmission component in the non-engaged condition until engine speed generally matches transmission component speed. The controller can directly control engagement by automatically actuating a movable transmission member or can indirectly control engagement by controlling engine speed.