Hydraulic system for energy regeneration in a work machine such as a wheel loader
A hydraulic system is adapted to recover potential and kinetic energy of a work attachment of a work machine. A valve arrangement may configure the hydraulic system in various modes. The hydraulic system may provide suspension and/or actuation for the work attachment. The energy of the work attachment may move a rod of a first cylinder. The rod may pressurize fluid within the first cylinder. The pressurized fluid may flow from the first cylinder through a valve and into an accumulator. The first cylinder may amplify pressure of the fluid. The pressurized fluid in the accumulator may actuate the first cylinder. The movement of the rod of the first cylinder may cause simultaneous actuation of a second cylinder. A controller may monitor pressures and positions of components of the hydraulic system and control the valve arrangement.
1. A method of reusing energy of a work attachment of a work machine, the method comprising:
opening hydraulic fluid flow through a first flow control device, the first flow control device fluidly connected between an accumulator and a head chamber of a first hydraulic cylinder;
compressing the head chamber by moving a piston and rod of the first hydraulic cylinder with the work attachment and thereby charging the accumulator with the hydraulic fluid flow; and
simultaneously actuating a second hydraulic cylinder by opening hydraulic fluid flow through a second flow control device connected between the second hydraulic cylinder and the head chamber of the first hydraulic cylinder;
wherein the first hydraulic cylinder further includes a rod chamber and a second flow control device fluidly connects the head chamber to the rod chamber and thereby amplifies a hydraulic pressure generated within the first hydraulic cylinder and used to charge the accumulator.
2. The method of claim 1 , wherein the moving of the piston and rod is at least partly done by gravity acting on mass of the work attachment.
3. The method of claim 1 , wherein the moving of the piston and rod is at least partly done by decelerating mass of the work attachment.
4. The method of claim 1 , wherein the first hydraulic cylinder, the accumulator, and the first fluid flow control device belong to a suspension system of the work machine.
5. The method of claim 1 , wherein the work machine is a wheel loader and the first hydraulic cylinder is connected to a boom of the work attachment.
6. The method of claim 5 , wherein the first hydraulic cylinder, the accumulator, and the first fluid flow control device belong to a boom suspension system of the wheel loader.