Boom potential energy recovery of hydraulic excavator
A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.
1. A hydraulic system for a mobile construction vehicle, comprising:
a variable displacement track motor configured to be coupled to a track of the mobile construction vehicle to drive the track;
an accumulator for storing pressurized hydraulic fluid for use as a power supply to a non-track load implement;
a pump dedicated to the track motor; and
control valving that is operable between a first position at which the control valving directs hydraulic fluid from the dedicated pump to the variable displacement track motor to drive the variable displacement track motor ( 60 a , 60 b ), and a second position at which the control valving directs hydraulic fluid from the dedicated pump to the accumulator.
2. The hydraulic system of claim 1 , wherein the control valving includes a proportional valve that diverts flow from the track motor to the accumulator a proportional manner.
3. The hydraulic system of claim 1 , wherein the control valving is configured such that when the control valving is not operating in the first position to direct hydraulic fluid to the track motor the control valving is operating in the second position to direct hydraulic fluid to the accumulator.
4. The hydraulic system of claim 1 , wherein the non-track load implement includes a swing motor for driving a swing of the mobile construction vehicle, and the accumulator is configured to provide the stored pressurized hydraulic fluid to the swing motor to drive the swing motor.
5. The hydraulic system of claim 1 , wherein the non-track load implement includes a swing motor for driving a swing of the mobile construction vehicle, and wherein in the second position the control valving directs hydraulic fluid from the pump to the swing motor to drive the swing motor.
6. A hydraulic system for storing pressurized hydraulic fluid from a pump of a mobile construction vehicle and using the stored hydraulic fluid to power a track motor of the mobile construction vehicle, the hydraulic system comprising:
an accumulator configured to be coupled to the pump to receive and store the pressurized hydraulic fluid from the pump; and
control valving that is operable between a first position at which the control valving directs hydraulic fluid from the pump to the accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to the track motor to power the track motor.
7. The hydraulic system of claim 6 , further comprising the track motor, and wherein the track motor is a bidirectional overcenter track motor.
8. The hydraulic system of claim 6 , wherein accumulator is stored within the track.
9. The hydraulic system of claim 6 , wherein the control valving includes a proportional valve between the accumulator and the track motor that is configured, when the accumulator is pressurized with hydraulic fluid, to open to allow the accumulator to provide the pressurized hydraulic fluid to the track motor to drive the track motor.
10. The hydraulic system of claim 9 , wherein the control valving includes a directional valve that, when the control valving is in the second position, the directional valve directs hydraulic fluid from the pump to the track motor to assist the accumulator in driving the track motor.
11. The hydraulic system of claim 10 , wherein when the accumulator is depleted of pressurized hydraulic fluid the directional valve continues to direct hydraulic fluid from the pump to the track motor to drive the track motor without the accumulator.