| 摘要 |
<p>1,173,317. Fuel injection pumps. C.A.V. Ltd. May 16, 1967 [May 31, 1966], No.24085/66. Heading F1A. In a fuel injection pump having a cam actuated plunger and a combined inlet, outlet and distributing valve, the cam is so shaped that after an injection stroke and after communication of the delivery passage with an outlet port has been broken and before the inlet passage opens to the inlet port the plunger is allowed to move a predetermined extent in the direction in which it moves during a filling stroke, the plunger then being held against movement in said direction for a short period before being allowed to move its fullest extent. In one embodiment in which the communication is broken by rotation of the distributor, the cam profile is as shown in Fig.4; after completion of delivery it allows retraction and a dwell to point B at which the communication is broken, followed by retraction, dwell and retraction to point C at which the inlet opens. In a second embodiment in which communication is broken by means of a shouldered valve in the delivery port, the cam profile is as shown in Fig. 5; after completion of delivery it allows retraction to point E, at which the shouldered valve closes, retraction, dwell and retraction to point F at which the inlet opens. The delivery passage and outlet port may be disconnected at any point between E and G. The arrangement is such that the fuel line is first relieved of pressure and after communication between the delivery passage and outlet port has been broken, the pump passages are relieved of pressure.</p> |
