| 摘要 |
<p>The flow from a controlled pre-supply pump to a high-pressure pump is divided with the aid of a lubricating flow valve, fig.2, into a high-pressure supply flow and a lubricating flow. The pre-supply pump has a linearly rising characteristic supply curve 1 as shown in fig.1 which plots flow rate against rotational speed. In order to improve control characteristics, especially in the lower rotation speed range, the lubricating flow valve has a characteristic curve 2 which matches curve 1 over a first range I of rotational speeds (ie practically the whole flow is branched off as the lubricating flow), then rises linearly but at a lower rate than curve 1 over a second range II (ie the high-pressure flow slowly increases) and falls linearly over a final range III. The lubricating flow valve has a body 4 with a bore 5 which receives a reciprocatable piston 6 in the form of a hollow cylinder. Pressed into one end of the valve body 4 is a spigot 7 which has and a transverse bore 11 and a longitudinal bore 12 with a reduced diameter restrictor portion 13. The piston 6 is urged away from the spigot 7 by a spring 10 but can be forced by fuel flowing in direction 16 against a valve seat 15 formed on the spigot 7.</p> |
