Parker-hannifin Corporation

Yisheng Zhang

John Loeffler

Guobiao Song

A hybrid drive system for use in a drive train assembly of a vehicle includes a control apparatus that operates the hybrid drive system in either a normal energy recovery mode in response to a braking request or an extended braking mode in response to an extended braking request. In the normal energy recovery mode, fluid is pumped to an accumulator, which consumes kinetic energy of the vehicle and causes deceleration of the vehicle. In the extended braking mode, fluid is pumped through a pressure relief valve containing a restriction, which consumes the kinetic energy of the vehicle and causes deceleration of the vehicle. If the temperature of the fluid being pumped through the pressure relief valve exceeds a predetermined value, fluid is alternatively pumped through a pump/motor operating in a motoring mode, which consumes the kinetic energy of the vehicle and causes deceleration the vehicle.

Apparatus and method for operating a hybrid drive system during an extended braking condition

A method of operating a vehicle includes the steps of: entering a drive shaft test mode; receiving a command to position a yoke to drive the shaft; regulating the shaft speed so as to be below a predefined threshold; and determining whether a drive shaft is available based on whether an actual drive shaft speed is detected above the predefined threshold. When the detected actual drive shaft speed is above the predefined threshold, it is determined that the drive shaft is not available and the vehicle is disabled to prevent damage to the vehicle. When the detected actual drive shaft speed is not above the predefined threshold, it is determined that the drive shaft is available, and the vehicle may be operated as is typical. The methods may be performed by an controller executing program code stored on a non-transitory computer readable medium.

Drive shaft detection for pump or motor protection

A system and method of dithering speed and/or torque for shifting a transmission of a vehicle having an engine, a reversible, variable displacement hydraulic motor/pump which can be driven by the engine, a hydraulic accumulator supplied by said motor/pump, and at least one reversible hydraulic driving motor for propelling the vehicle supplied with fluid by the hydraulic accumulator and/or by said motor/pump operating as a pump. A transmission unit connects the engine with the variable displacement hydraulic motor/pump during a first mode of operation (city mode) and connects the engine to a vehicle drive wheel during a second mode of operation. The system utilizes stored hydraulic energy to dither the output of the driving motor in order to achieve quick and smooth shifts between city and highway mode, or between various ranges within the city mode.

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Dublin, OH, United States of America

Yisheng Zhang