| 摘要 |
PURPOSE: To realize high-pressure fuel delivery at a constant flow rate by shaping each of cams, which are formed integrally with a drive shaft to reciprocate each of pistons of in-line pump units, to have a profile that can ensure null acceleration in a fuel delivery state and a constant fuel flow rate for a 360-degree rotation of the pump. CONSTITUTION: Each of pistons 9 in two in-line pump units is reciprocated via a tappet 7 working in association with two cams 12 disposed integrally with a cam shaft 8 by rotating the cam shaft 8 in association with engine rotation. Therefore, the fuel sucked into a cylinder 10 from an intake valve 13 is compressed and subsequently delivered via a delivery valve 14 to be supplied to a fuel injection valve. In such a kind of injection pump, the cam 12 is shaped to have a double-lobed profile maintaining a constant speed so as to ensure null acceleration in a delivery state of the fuel and a constant fuel flow rate for a 360-degree rotation of the pump. Further, the two cams 12 are staggered from each other at a suitable angle and are disposed integrally with the cam shaft 8. |
