HYDRAULIC CIRCUIT FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide a hydraulic circuit for an internal combustion engine improving responsiveness to load. SOLUTION: A main valve 2 includes an input port 27 connected to a hydraulic pressure source P, an output port 26 connected to a supply passage 6 communicating to a load A side, a back pressure chamber 24, and a main valve element 22 making the input port 27 and the output port 26 communicate in response to pressure drop of the back pressure chamber 24. A pilot control solenoid valve 3 includes a control port 39 connected to the back pressure chamber 24 of the main valve 2, an output port 38, a valve element or a spool 34 switched in response to signal to a solenoid 55 to intercept communication between the control port 39 and the output port 38. The output port 26 of the pilot control solenoid valve 3 is connected to the supply passage 6 from the main valve 2. COPYRIGHT: (C)2005,JPO&NCIPI