Metering valve arrangement

摘要

A metering valve arrangement (46) comprises a metering valve member (48) which is angularly adjustable within a metering valve bore (49) provided in a metering valve housing (55) and an adjustment arrangement (110) for adjusting the axial position of the metering valve member (48) within the metering valve bore (49). The metering valve arrangement (46) includes a first opening (70) provided in the metering valve member (48) which is registerable with a first outlet (74) provided in the metering valve housing (55) to control a first rate of flow of fluid through the first outlet (74) depending on the angular position of the metering valve member (48) within the bore (49), and a second opening (80) provided in the metering valve member (48) which is registerable with a second outlet (84) provided in the metering valve housing (55) to control a second rate of flow of fluid through the second outlet (84). The first and second outlets and the first and second openings are shaped and configured to ensure the first rate of flow of fluid maintains a substantially constant relationship to the second rate of flow of fluid for any axial position of the metering valve member (48) within the metering valve bore (49). <??>The metering valve arrangement is particularly suitable for use in an advance arrangement for adjusting the timing of fuel delivery by a pump, in which the first outlet (74) of the metering valve arrangement (46) communicates with a low pressure drain and a first rate of flow of fuel through the first outlet determines fuel pressure within a light load control chamber (60) of the advance arrangement, and wherein the second outlet (84) of the metering valve arrangement (46) communicates with the pump and a second rate of flow of fuel through the second outlet (84) determines the pressure of fuel delivered to the pump. <IMAGE>