Engine Assist by Recovering Swing Kinetic Energy

摘要

An energy recovery system for a machine having a movable work tool, a swing motor to swing the work tool about a vertical axis, a pump providing pressurized fluid to the swing motor, a power source outputting power to drive the pump, and a controller. The energy recovery system may include a first accumulator, a swing charge valve selectively connecting the swing motor to the first accumulator, an assist motor operatively connected to the power source, and a discharge selectively connecting the first accumulator to the assist motor. The swing charge valve may fluidly connect the swing motor to the first accumulator when fluid pressure from the swing motor is greater than a charge set pressure. The controller may cause the discharge valve to fluidly connect the first accumulator with the assist motor when the power demand on the power source is greater than a minimum assisted power demand.

主权项

1. A machine, comprising:
a work tool movable through a range of motion; a swing motor configured to swing the work tool about a vertical axis; a pump selectively fluidly connected to the swing motor to provide pressurized fluid to cause the swing motor to swing the work tool; a power source operatively connected to the pump to output power to drive the pump; an energy recovery system comprising:
a first accumulator,a swing charge valve having a normally closed position, an open position, and a charge set pressure, the swing charge valve being positioned to selectively fluidly connect the swing motor to the first accumulator, wherein the swing charge valve moves from the normally closed position to the open position and fluidly connects the swing motor to the first accumulator when a swing motor fluid pressure communicated to the swing charge valve from the swing motor is greater than the charge set pressure,an assist motor operatively connected to the power source, anda discharge valve having a normally closed position and an open position, the discharge valve being positioned to selectively fluidly connect the first accumulator to the assist motor; and a controller operatively connected to the discharge valve, wherein:
the controller is configured to determine a power demand on the power source for output power, andthe controller is configured to cause the discharge valve to move from the normally closed position to the open position to fluidly connect the first accumulator with the assist motor in response determining that the power demand on the power source for output power is greater than a minimum assisted power demand.