Abstract: A hydraulic system for a vehicle clutch assembly can include an on-demand variable displacement pump and a purge valve for regulating hydraulic pressure supplied to the clutch(es). The hydraulic pressure at the pump can have multiple displacement settings to compensate for variable changes in clutch pressure requirements. The purge valve can be configured to purge hydraulic pressure from the hydraulic system so that an optimum, controllable, and/or pre-determined operating pressure can be supplied to the clutch(es). The system can be configured to provide accurate control of clutch(es) when a drivetrain is being automatically controlled to switch between a low gear ratio and a high gear ratio.

Abstract: An apparatus and method for automatically controlling a drivetrain coupled to at least one drive wheel of a vehicle can include providing a first assembly including a low range drive ratio and a high range drive ratio. An electronic control unit can be configured to receive information from at least one sensor located on the vehicle and to provide an output signal based on the information. An actuator mechanism can be provided and configured to cause the first assembly to operate at a selected one of the low range drive ratio and the high range drive ratio based on instructions from the control unit. Separate algorithms can be provided to determine when to actuate from the high range drive ratio to the low range drive ratio and vice versa.

Abstract: A transaxle can include a housing, a low range gear assembly, and a differential gear assembly. The low range gear assembly can be mounted in the housing and can include a ring gear, a carrier, planet gears, a sun gear, and a clutch. The ring gear, the carrier, and the sun gear can be mounted in the housing. The planet gears can be rotatably mounted on the carrier and can engage the ring gear while the sun gear can engage the planet gears. The clutch can be selectively movable between a first position where the clutch engages each of the sun gear and the carrier and permits rotation of the sun gear relative to the housing and a second position where the clutch engages each of the sun gear and the housing and rotationally fixes the sun gear relative to the housing.

Abstract: A vehicle drivetrain can include various structures, such as a multi-ratio transmission, a two-speed final drive assembly connected in series with the multi-ratio transmission and including a low speed final drive ratio and a high speed final drive ratio, a pair of front driveshafts driven by the two-speed final drive assembly, a pair of rear driveshafts, a rear differential assembly connected to the two-speed final drive assembly, and a control assembly including. The control assembly can include a controller in electrical communication with portions of the rear differential assembly, such as a variable displacement pump and purge valve. An input array can be in electrical communication with the controller and can include a plurality of sensors, and at least one switch accessible to an operator of the vehicle. Various related methods can also be executed for control and operation of such a drivetrain.

Abstract: A vehicle anti-rollback system and method can be incorporated into a vehicle that includes a pair of front wheels, a pair of rear wheels, a power unit, and a transmission connecting the power unit to at least one wheel of the front and rear wheels. The transmission can include a plurality of forward drive ratios and at least one reverse drive ratio and a two speed final drive ratio transmission configured to select between a high range drive ratio and a low range drive ratio when the transmission is in one of the plurality of forward drive ratios. A controller can be provided that senses a vehicle rollback condition. When the rollback condition is detected, the controller can decrease torque distributed from the power unit of the vehicle to the at least one wheel, and can actuate a brake. While the vehicle is braked and torque transfer is reduced, the controller can execute drive ratio changeover in a stable manner from the high range drive ratio to the low range drive ratio.

Abstract: A vehicle anti-rollback system and method can be incorporated into a vehicle that includes a pair of front wheels, a pair of rear wheels, a power unit, and a transmission connecting the power unit to at least one wheel of the front and rear wheels. The transmission can include a plurality of forward drive ratios and at least one reverse drive ratio and a two speed final drive ratio transmission configured to select between a high range drive ratio and a low range drive ratio when the transmission is in one of the plurality of forward drive ratios. A controller can be provided that senses a vehicle rollback condition. When the rollback condition is detected, the controller can decrease torque distributed from the power unit of the vehicle to the at least one wheel, and can actuate a brake. While the vehicle is braked and torque transfer is reduced, the controller can execute drive ratio changeover in a stable manner from the high range drive ratio to the low range drive ratio.

Abstract: A vehicle drivetrain can include various structures, such as a multi-ratio transmission, a two-speed final drive assembly connected in series with the multi-ratio transmission and including a low speed final drive ratio and a high speed final drive ratio, a pair of front driveshafts driven by the two-speed final drive assembly, a pair of rear driveshafts, a rear differential assembly connected to the two-speed final drive assembly, and a control assembly including. The control assembly can include a controller in electrical communication with portions of the rear differential assembly, such as a variable displacement pump and purge valve. An input array can be in electrical communication with the controller and can include a plurality of sensors, and at least one switch accessible to an operator of the vehicle. Various related methods can also be executed for control and operation of such a drivetrain.

Abstract: An apparatus and method for automatically controlling a drivetrain coupled to at least one drive wheel of a vehicle can include providing a first assembly including a low range drive ratio and a high range drive ratio. An electronic control unit can be configured to receive information from at least one sensor located on the vehicle and to provide an output signal based on the information. An actuator mechanism can be provided and configured to cause the first assembly to operate at a selected one of the low range drive ratio and the high range drive ratio based on instructions from the control unit. Separate algorithms can be provided to determine when to actuate from the high range drive ratio to the low range drive ratio and vice versa.

Abstract: A transaxle can include a housing, a low range gear assembly, and a differential gear assembly. The low range gear assembly can be mounted in the housing and can include a ring gear, a carrier, planet gears, a sun gear, and a clutch. The ring gear, the carrier, and the sun gear can be mounted in the housing. The planet gears can be rotatably mounted on the carrier and can engage the ring gear while the sun gear can engage the planet gears. The clutch can be selectively movable between a first position where the clutch engages each of the sun gear and the carrier and permits rotation of the sun gear relative to the housing and a second position where the clutch engages each of the sun gear and the housing and rotationally fixes the sun gear relative to the housing.

Abstract: An RF module adapted for direct surface mounting to the top surface of the front end of the motherboard of a picocell. The module comprises a printed circuit board having a plurality of direct surface mounted electrical components defining respective signal transmit and receive sections for RF signals. The signal transmit section is defined by at least a transmit bandpass filter, a power amplifier, an isolator, a coupler, and a duplexer. The signal receive section is defined by at least the duplexer, a receive low pass filter, a low-noise amplifier, and a receive bandpass filter. A lid covers selected ones of the electrical components except for at least the power amplifier. A plurality of through-holes defined in the printed circuit board below the amplifier allow for the dissipation of heat created by the amplifier. At least one aperture in the board is adapted to accept a screw or the like for securing the module to the motherboard of the picocell.

Abstract: A hydraulic system for a vehicle clutch assembly can include an on-demand variable displacement pump and a purge valve for regulating hydraulic pressure supplied to the clutch(es). The hydraulic pressure at the pump can have multiple displacement settings to compensate for variable changes in clutch pressure requirements. The purge valve can be configured to purge hydraulic pressure from the hydraulic system so that an optimum, controllable, and/or pre-determined operating pressure can be supplied to the clutch(es). The system can be configured to provide accurate control of clutch(es) when a drivetrain is being automatically controlled to switch between a low gear ratio and a high gear ratio.

Abstract: A method of producing hydrocarbons from a subterranean formation.