Abstract: A swing drive system for an excavator is provided which utilizes a prime mover mechanically connected to a first hydraulic pump/motor and a second hydraulic pump/motor mechanically connected to a swing mechanism. The system includes a hydraulic circuit connecting a hydraulic fluid reservoir, a hydraulic accumulator, the first hydraulic pump/motor, and the second hydraulic pump/motor. The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers, including the swing drive.

Abstract: A hydraulic system (40) for a work machine comprising a priority circuit (41) including at least a first priority actuator (47, 48) and a priority control valve (58) for controlling the supply of hydraulic fluid to the first priority actuator (47, 48) and for providing a load sense signal indicative of the load acting on the first priority actuator (47, 48); an auxiliary circuit (42) including at least a first auxiliary actuator (51) and at least a first auxiliary control valve (80) for controlling the supply of hydraulic fluid to the first auxiliary actuator (51); at least a first pump (46) for producing a flow of hydraulic fluid; and a priority valve (74) for distributing the flow from the pump (46) to the priority circuit (41) and auxiliary circuit (42) for operating the respective actuators thereof, with priority being given to the priority circuit (41) as a function of the load sense signal.

Abstract: A control system for a working machine that includes a power consumer (14) includes a prime mover (12), an energy storage unit (24) for storing energy, an auxiliary power unit (20) for generating power or consuming power, the auxiliary power unit (20) having a first connection (20a) coupled to the prime mover (12) and a second connection couplable to the energy storage unit (24). A controller (18) operatively coupled to the prime mover (12) and operatively couplable to the power consumer (14) is configured to estimate a required power of the power consumer (14), and to command the prime mover (14) to operate at an optimal operating point that produces the estimated required power.

Abstract: A swing drive system for an excavator is provided which utilizes a prime mover mechanically connected to a first hydraulic pump/motor and a second hydraulic pump/motor mechanically connected to a swing mechanism. The system includes a hydraulic circuit connecting a hydraulic fluid reservoir, a hydraulic accumulator, the first hydraulic pump/motor, and the second hydraulic pump/motor. The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers, including the swing drive.

Abstract: A hybrid swing drive system (1) of a hydraulic construction machine includes a variable displacement hydraulic swing pump (3) operable by a prime mover (2); a hydraulic swing motor (16) for performing a swing function of the machine; an accumulator (10); a controller (244); a swing control valve assembly (15) disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor; and an accumulator control valve (12) having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path.

Abstract: A swing drive system (11) for an excavator is provided which utilizes a prime mover (20) mechanically connected to a first hydraulic pump/motor (30) and a second hydraulic pump/motor (32) mechanically connected to a swing mechanism (70). The system includes a hydraulic circuit (31) connecting a hydraulic fluid reservoir (42), a hydraulic accumulator (40), the first hydraulic pump/motor (30), and the second hydraulic pump/motor (32). The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers (62,64,66), including the swing mechanism.

Abstract: A hydraulic system (40) for a work machine comprising a priority circuit (41) including at least a first priority actuator (47, 48) and a priority control valve (58) for controlling the supply of hydraulic fluid to the first priority actuator (47, 48) and for providing a load sense signal indicative of the load acting on the first priority actuator (47, 48); an auxiliary circuit (42) including at least a first auxiliary actuator (51) and at least a first auxiliary control valve (80) for controlling the supply of hydraulic fluid to the first auxiliary actuator (51); at least a first pump (46) for producing a flow of hydraulic fluid; and a priority valve (74) for distributing the flow from the pump (46) to the priority circuit (41) and auxiliary circuit (42) for operating the respective actuators thereof, with priority being given to the priority circuit (41) as a function of the load sense signal.

Abstract: A control system for a working machine that includes a power consumer (14) includes a prime mover (12), an energy storage unit (24) for storing energy, an auxiliary power unit (20) for generating power or consuming power, the auxiliary power unit (20) having a first connection (20a) coupled to the prime mover (12) and a second connection couplable to the energy storage unit (24). A controller (18) operatively coupled to the prime mover (12) and operatively couplable to the power consumer (14) is configured to estimate a required power of the power consumer (14), and to command the prime mover (14) to operate at an optimal operating point that produces the estimated required power.

Abstract: Provided is a hydrostatic system including a first hydraulic unit, second and third hydraulic units fluidly connected to the first hydraulic unit, and a hydraulic accumulator fluidly connected to the first hydraulic unit and the third hydraulic unit, where the hydrostatic system is selectively coupleable to a prime mover and/or one or more wheels. The hydrostatic system may be operated in a hydrostatic driving mode where the hydraulic accumulator is isolated from the system and the first hydraulic unit drives the second and third hydraulic units, and in a hybrid driving mode where the hydraulic accumulator supplies fluid to the third hydraulic unit and the first hydraulic unit supplies or does not supply fluid to the second hydraulic unit. By selectively coupling the hydrostatic system to the prime mover, the hydrostatic system and the prime mover may be operated independent of one another.

Abstract: A hybrid swing drive system (1) of a hydraulic construction machine includes a variable displacement hydraulic swing pump (3) operable by a prime mover (2); a hydraulic swing motor (16) for performing a swing function of the machine; an accumulator (10); a controller (244); a swing control valve assembly (15) disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor; and an accumulator control valve (12) having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path.

Abstract: A swing drive system (11) for an excavator is provided which utilizes a prime mover (20) mechanically connected to a first hydraulic pump/motor (30) and a second hydraulic pump/motor (32) mechanically connected to a swing mechanism (70). The system includes a hydraulic circuit (31) connecting a hydraulic fluid reservoir (42), a hydraulic accumulator (40), the first hydraulic pump/motor (30), and the second hydraulic pump/motor (32). The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers (62,64,66), including the swing mechanism.