Hydraulic control system for swing motor

A machine comprising:

• a swing motor having a first chamber port and a second chamber port;
• a pump;
• a tank:
• a swing control valve coupled between the swing motor and the pump and the tank to selectively control a fluid flow from the pump to the swing motor and from the swing motor to the tank, the swing control valve having a first port and a second port, the swing control valve movable from a neutral position, where the fluid flow is inhibited, to either a first working position, where the first port is in fluid communication with a first chamber port of the swing motor and the pump and the second port is in fluid communication with a second chamber port of the swing motor and the tank, or a second working position, where the first port is in fluid communication with the first chamber port of the swing motor and the tank and the second port is in fluid communication with the second chamber port of the swing motor and the pump;
• a first conduit coupled between the first port of the swing control valve and the first chamber port of the swing motor;
• a second conduit coupled between the second port of the swing control valve and the second chamber port of the swing motor;
• a first chamber valve and a second chamber valve coupled to the first conduit and the second conduit, respectively;
• an accumulator fluidly coupled to each of the first and second conduits and configured to selectively receive a pressurized fluid discharged from the swing motor;
• and
• a controller configured to determine a charge mode for the accumulator, wherein during the charge mode the controller is configured to:
• selectively move the swing control valve away from one of the first and the second working positions;
• and
• selectively move one of the first and second chamber valves to reduce the fluid flow between the swing motor and the tank such that the pressurized flow discharged from the swing motor is directed to the accumulator.

A method of operating a hydraulic circuit, comprising:

• determining a charge mode of operation of a hydraulic circuit having a swing motor, a pump, a tank, and an accumulator with a controller;
• selectively moving a swing control valve away from one of its first and second working positions, the swing control valve coupled between the swing motor and the pump and the tank, the swing control valve having a first port and a second port, the swing control valve is movable from a neutral position to either the first working position, where the first port is in fluid communication with a first chamber port of the swing motor and the pump and the second port is in fluid communication with a second chamber port of the swing motor and the tank, or the second working position, where the first port is in fluid communication with the first chamber port of the swing motor and the tank and the second port is in fluid communication with the second chamber port of the swing motor and the pump;
• and
• selectively moving one of a first chamber valve and a second chamber valve to reduce fluid flow between the swing motor and the tank such that a pressurized flow discharged from the swing motor is directed to the accumulator fluidly coupled to each of a first conduit and a second conduit, wherein the first chamber valve and the second chamber valve are coupled to the first conduit and the second conduit, respectively, the first conduit coupled between the first port of the swing control valve and the first chamber port of the swing motor, the second conduit coupled between the second port of the swing control valve and the second chamber port of the swing motor.