Abstract: A hydraulic circuit for an adaptive park braking system and method of operation thereof. The method of operating an adaptive park braking system includes providing a vehicle having a motor, a front axle system, a rear axle system, wherein the front axle system has one or more front axle braking systems and the rear axle system has one or more rear axle braking systems. Identifying when the vehicle is engaged in a digging operation. Disconnecting the front axle system or the rear axle system from driving engagement with the motor of the vehicle. Activating the one or more braking systems of the disconnect axle system to apply an amount of force to the disconnected axle system of the vehicle. Then applying an amount of torque with the motor to the axle system in driving engagement with the motor.

Abstract: A hydraulic circuit for an adaptive park braking system and method of operation thereof. The method of operating an adaptive park braking system includes providing a vehicle having a motor, a front axle system, a rear axle system, wherein the front axle system has one or more front axle braking systems and the rear axle system has one or more rear axle braking systems. Identifying when the vehicle is engaged in a digging operation. Disconnecting the front axle system or the rear axle system from driving engagement with the motor of the vehicle. Activating the one or more braking systems of the disconnect axle system to apply an amount of force to the disconnected axle system of the vehicle. Then applying an amount of torque with the motor to the axle system in driving engagement with the motor.

Abstract: A hydraulic hybrid powertrain for a vehicle is disclosed. The powertrain has an internal combustion engine selectively drivingly engaged with an input of a stepped-ratio transmission through a torque converter and through a speed direction changing device. An output of the stepped-ratio transmission is selectively drivingly engaged with a vehicle output. An intermediate gear set is drivingly engaged with the speed direction changing device and drivingly engaged with the input of the stepped-ratio transmission. A hydraulic machine in fluid communication with a hydraulic accumulator assembly, a transmission shaft of the hydraulic machine being drivingly engaged or selectively drivingly engaged with the intermediate gear set for providing energy to the intermediate gear set and for absorbing energy from the intermediate gear set. Also disclosed are methods of operating the hydraulic hybrid powertrain.

Abstract: A hydrostatic driveline has a power source and a hydrostatic pump in driving engagement with the power source; a primary driveline shaft in driving engagement with the power source. The driveline also has a first transmission portion and a second transmission portion in driving engagement with the first transmission portion. A hydrostatic motor is in fluid communication with the hydrostatic pump and is in driving engagement with the first transmission portion. A vehicle output is in driving engagement with the second transmission portion. The primary driveline shaft is also in driving engagement with the second transmission portion. The hydrostatic driveline may be operated in a hydrostatic mode or in a direct drive mode using the primary driveline shaft and the second transmission portion.

Abstract: A method of charging a hydro-pneumatic energy storage system is described. The system has a first hydro-pneumatic accumulator with a first hollow vessel. Disposed within the first hollow vessel is a first compressible volume containing a first amount of gas. The system has a second hydro-pneumatic accumulator with a second hollow vessel. Disposed within the second hollow vessel is a second compressible volume containing a second amount of gas. The gas contained in the first volume is pre-pressurized to a first hydrostatic pre-charge pressure and the gas contained in the second volume is pre-pressurized to a second hydrostatic pre-charge pressure. The second pre-charge pressure is higher than the first pre-charge pressure.

Abstract: A series hydraulic hybrid system for a vehicle is described. The hydraulic hybrid system has a hydraulic circuit and a high pressure accumulator. The hydraulic circuit has a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit. The high pressure hydraulic accumulator is in fluid communication with the hydraulic circuit and a low pressure hydraulic accumulator in fluid communication with the hydraulic circuit. The high pressure hydraulic accumulator is in fluid communication with the hydraulic circuit through a proportional flow control valve. The proportional flow control valve is adapted to continuously vary a flow of hydraulic fluid between the high pressure hydraulic accumulator and the hydraulic circuit.

Abstract: A series hydraulic hybrid system for a vehicle is described. The system has a hydraulic circuit, a hydraulic working assembly, and a hydraulic accumulator assembly. The hydraulic circuit has a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit. The first hydraulic displacement unit is drivingly engaged with a power source. The hydraulic working assembly has a hydraulic implement and a hydraulic working pump in fluid communication with the hydraulic implement, the hydraulic working pump drivingly engaged with the power source. The hydraulic accumulator assembly has a high pressure hydraulic accumulator and a low pressure hydraulic accumulator. The hydraulic accumulator assembly selectively fluidly connects to the hydraulic circuit and the hydraulic accumulator assembly selectively fluidly connects to the hydraulic working assembly.

Abstract: The invention relates to a dual motor hydraulic hybrid transmission. The transmission comprises a power source, a hydraulic circuit including a pump drivingly engaged with the power source and two displacement units, a hydraulic accumulator assembly including high and low pressure accumulators, one or more control valves, and an output shaft drivingly engaged with the first hydraulic displacement unit. The displacement units are in fluid communication with the hydraulic pump. The accumulators are in fluid communication with the hydraulic circuit. The second hydraulic displacement unit is drivingly engaged with the output shaft.

Abstract: A rotary seal arrangement for use with a central tire inflation system is provided. The rotary seal arrangement comprises a stationary portion, a rotating portion, a first sealing ring, a second sealing ring, and a first bushing portion. The stationary portion defines a first air passage therethrough and the rotating portion defines a second air passage therethrough. The first sealing ring and the second sealing ring are each disposed on one of the rotating portion and the stationary portion. The first bushing is disposed on one of the rotating portion and the stationary portion. The first bushing is in dynamic sealing engagement with the first sealing ring. The stationary portion, the rotating portion, the first sealing ring, and the second sealing ring form a sealed cavity that facilitates fluid communication between the first air passage and the second air passage.

Abstract: A hydrostatic driveline and method of operating a hydrostatic driveline is provided. The hydrostatic driveline comprises a power source, hydrostatic pump, a hydrostatic motor, a direct drive link, a first transmission portion, and a second transmission portion. The direct drive link is in driving engagement with at least one of the power source and the hydrostatic pump. The first transmission portion is in driving engagement with a vehicle output and the hydrostatic motor. The second transmission portion is in driving engagement with the direct drive link and at least one of the vehicle output and the first transmission portion. The hydrostatic pump, the hydrostatic motor, and the first transmission portion form a first power path for the hydrostatic driveline and the direct drive link and the second transmission portion form a second power path for the hydrostatic driveline.

Abstract: A series hydraulic hybrid system for a vehicle and a method of operating the same is described. The series hydraulic hybrid system has a hydraulic circuit, high and low pressure hydraulic accumulators, and a control unit. The hydraulic circuit has first and second hydraulic displacement units in fluid communication. The first hydraulic displacement unit is drivingly engaged with an internal combustion engine. The high pressure hydraulic accumulator and the low pressure hydraulic accumulator are fluidly connected to the hydraulic circuit through at least one accumulator valve. The control unit is adapted to receive an input from an operator, compute a requested torque and a target system pressure based on the input, compare an accumulator pressure to the target system pressure, and control at least one of a speed of the internal combustion engine and a valve state of the accumulator valve based on the outcome of the comparison.

Abstract: A hydrostatic driveline has a power source and a hydrostatic pump in driving engagement with the power source; a primary driveline shaft in driving engagement with the power source. The driveline also has a first transmission portion and a second transmission portion in driving engagement with the first transmission portion. A hydrostatic motor is in fluid communication with the hydrostatic pump and is in driving engagement with the first transmission portion. A vehicle output is in driving engagement with the second transmission portion. The primary driveline shaft is also in driving engagement with the second transmission portion. The hydrostatic driveline may be operated in a hydrostatic mode or in a direct drive mode using the primary driveline shaft and the second transmission portion.

Abstract: A series hydraulic hybrid driveline for a vehicle is described. The driveline has a power source, a hydraulic circuit having a first hydraulic displacement unit and a second hydraulic displacement unit, a hydraulic accumulator assembly with high pressure and low pressure hydraulic accumulators, at least one accumulator valve, at least one input device, and a control unit. The first hydraulic displacement unit is drivingly engaged with the power source. The accumulator assembly is selectively fluidly connected to the hydraulic circuit through the accumulator valve. The control unit is configured to compute a total power requested from the power source based on an input command from the input device, compare the computed total power to a threshold power, and control a valve state of the accumulator valve based upon the result of the comparison. A method of controlling the driveline is also described.

Abstract: A rotary seal arrangement for use with a central tire inflation system is provided. The rotary seal arrangement comprises a stationary portion, a rotating portion, a first sealing ring, a second sealing ring, and a first bushing portion. The stationary portion defines a first air passage therethrough and the rotating portion defines a second air passage therethrough. The first sealing ring and the second sealing ring are each disposed on one of the rotating portion and the stationary portion. The first bushing is disposed on one of the rotating portion and the stationary portion. The first bushing is in dynamic sealing engagement with the first sealing ring. The stationary portion, the rotating portion, the first sealing ring, and the second sealing ring form a sealed cavity that facilitates fluid communication between the first air passage and the second air passage.

Abstract: A series hydraulic hybrid system for a vehicle and a method of operating the same is described. The series hydraulic hybrid system has a hydraulic circuit, high and low pressure hydraulic accumulators, and a control unit. The hydraulic circuit has first and second hydraulic displacement units in fluid communication. The first hydraulic displacement unit is drivingly engaged with an internal combustion engine. The high pressure hydraulic accumulator and the low pressure hydraulic accumulator are fluidly connected to the hydraulic circuit through at least one accumulator valve. The control unit is adapted to receive an input from an operator, compute a requested torque and a target system pressure based on the input, compare an accumulator pressure to the target system pressure, and control at least one of a speed of the internal combustion engine and a valve state of the accumulator valve based on the outcome of the comparison.

Abstract: A series hydraulic hybrid driveline for a vehicle is described. The driveline has a power source, a hydraulic circuit having a first hydraulic displacement unit and a second hydraulic displacement unit, a hydraulic accumulator assembly with high pressure and low pressure hydraulic accumulators, at least one accumulator valve, at least one input device, and a control unit. The first hydraulic displacement unit is drivingly engaged with the power source. The accumulator assembly is selectively fluidly connected to the hydraulic circuit through the accumulator valve. The control unit is configured to compute a total power requested from the power source based on an input command from the input device, compare the computed total power to a threshold power, and control a valve state of the accumulator valve based upon the result of the comparison. A method of controlling the driveline is also described.

Abstract: A hydraulic hybrid powertrain for a vehicle is disclosed. The powertrain has an internal combustion engine selectively drivingly engaged with an input of a stepped-ratio transmission through a torque converter and through a speed direction changing device. An output of the stepped-ratio transmission is selectively drivingly engaged with a vehicle output. An intermediate gear set is drivingly engaged with the speed direction changing device and drivingly engaged with the input of the stepped-ratio transmission. A hydraulic machine in fluid communication with a hydraulic accumulator assembly, a transmission shaft of the hydraulic machine being drivingly engaged or selectively drivingly engaged with the intermediate gear set for providing energy to the intermediate gear set and for absorbing energy from the intermediate gear set. Also disclosed are methods of operating the hydraulic hybrid powertrain.

Abstract: A method of charging a hydro-pneumatic energy storage system is described. The system has a first hydro-pneumatic accumulator with a first hollow vessel. Disposed within the first hollow vessel is a first compressible volume containing a first amount of gas. The system has a second hydro-pneumatic accumulator with a second hollow vessel. Disposed within the second hollow vessel is a second compressible volume containing a second amount of gas. The gas contained in the first volume is pre-pressurized to a first hydrostatic pre-charge pressure and the gas contained in the second volume is pre-pressurized to a second hydrostatic pre-charge pressure. The second pre-charge pressure is higher than the first pre-charge pressure.

Abstract: A series hydraulic hybrid system for a vehicle is described. The hydraulic hybrid system has a hydraulic circuit and a high pressure accumulator. The hydraulic circuit has a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit. The high pressure hydraulic accumulator is in fluid communication with the hydraulic circuit and a low pressure hydraulic accumulator in fluid communication with the hydraulic circuit. The high pressure hydraulic accumulator is in fluid communication with the hydraulic circuit through a proportional flow control valve. The proportional flow control valve is adapted to continuously vary a flow of hydraulic fluid between the high pressure hydraulic accumulator and the hydraulic circuit.

Abstract: A series hydraulic hybrid system for a vehicle is described. The system has a hydraulic circuit, a hydraulic working assembly, and a hydraulic accumulator assembly. The hydraulic circuit has a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit. The first hydraulic displacement unit is drivingly engaged with a power source. The hydraulic working assembly has a hydraulic implement and a hydraulic working pump in fluid communication with the hydraulic implement, the hydraulic working pump drivingly engaged with the power source. The hydraulic accumulator assembly has a high pressure hydraulic accumulator and a low pressure hydraulic accumulator. The hydraulic accumulator assembly selectively fluidly connects to the hydraulic circuit and the hydraulic accumulator assembly selectively fluidly connects to the hydraulic working assembly.