FUEL PRESSURE REGULATING MECHANISM FOR DISTRIBUTOR TYPE FUEL INJECTION PUMP

PROBLEM TO BE SOLVED: To hold the internal pressure of a fuel gallery appropriately regardless of temperature change by disposing a temperature compensating device provided with a pressure regulating valve with the valve opening pressure regulated according to the temperature of fuel, at a fuel return passage branching off from a fuel feed passage and leading to the feed pump inlet side or a fuel tank. SOLUTION: A pressure regulating fuel passage 4 (4a, 4b) is disposed branching off from a fuel feed passage 2 from a feed pump FP to a fuel gallery chamber G, and a pressure regulating valve 5 is interposed at the pressure regulating fuel passage 4. In fuel pressure regulating mechanism of such constitution, the pressure regulating fuel passage 4 is provided with a temperature element 8 for regulating the valve opening pressure of the pressure regulating valve 5. In this temperature element 8, a thermosensitive part 8a facing a fuel passage 13 is protruded from a body part 8b, and thermosensitive wax is filled inside from the thermosensitive part 8a to the body part 8b. This thermosensitive wax is changed in volume reacting to the temperature of fuel coming in contact with the thermosensitive part 8a so as to expand/ contract a push rod 8c to regulate the valve opening pressure of the pressure regulating valve 5.