| 摘要 |
PURPOSE:To restrain the temperature of an injection pump from abnormally increasing, by increasing the flow rate of overflow fuel returning to a fuel tank from a pump chamber when the rotational speed of an engine is lower than a predetermined value. CONSTITUTION:The body 2 of a valve device 11 in which a movable piston 13 is slidably disposed is screwed into an overflow port 7 formed in a housing 3 defining a pump chamber 4 therein. Since the pressure in the pump chamber 4 is lower than that corresponding to the idling operation of the engine when the rotational speed of the engine is lower than a predetermined value, the movable piston 13 is held by a spring 16 at a position where the piston 13 abuts against a stopper 17, and an excessive fuel in the pump chamber 4 flows from a passage 18 to a return passage 19 through an orifice 16 and a communication hole 15a, and is therefore returned to a fuel tank. With this arrangement the amount of circulated fuel is increased to enhance the capacity of cooling, thereby it is possible to prevent the temperature of the injection pump from abnormally increasing. |
