Electronic control state: the control hydraulic signal related to the displacement change is the front pump oil flow, the rear pump oil flow and the pilot oil and negative flow. The oil flow of the front and rear pumps directly controls the oil pump, and the pilot oil is controlled after being throttled by the electric proportional valve Oil pump, we can call it the pilot secondary pressure. Let's take the control of the pump as an example to analyze the change of displacement.
In the electronic control state, the pilot secondary oil flow alone controls the secondary piston, and the negative flow does not participate in direct control. Instead, the negative pressure sensor collects its pressure parameters and provides them to the computer. The computer calculates as a control for the electric proportional valve current. Parameters to control the pilot secondary oil flow; in the hydraulic control state, the pilot secondary oil flow is cut off by the hydraulic-modified electronic control valve, and does not participate in the control of the secondary piston. The secondary piston is directly controlled by negative flow alone. The working direction of the secondary piston is to push the spool valve spool to move to the left, and it is balanced by its own spring return.
