| 摘要 |
<p>D-4,603 C-3268 DIESEL INJECTION PUMP TIMING CONTROL WITH ELECTRONIC ADJUSTMENT An engine driven fuel injection pump has a cam and pump plungers movable relative to the cam to translate the contour of the cam into a sequence of pumping strokes. A timing control mechanism, used to vary the rotative position of the cam as a function of engine operation, includes a control piston mounted in a cylinder and connected to the cam to control the position thereof whereby to advance and retard the relative timing of the pumping strokes. Movement of the control piston is controlled by hydrualic fluid supplied from a source of fluid under a pressure correlated with the operating speed of the associated engine. The control piston is slidable between a power piston biased by a resilient means in one direction and actuated in the opposite direction by hydraulic fluid from the source of fluid under pressure. A landed valve has its stem fixed to the spring biased means and its body portion is axially slidable in the control piston to control the flow of hydraulic fluid to either one end of the control piston for actuation thereof or to the opposite end of said control piston which is in fluid communication with fuel in the pump housing maintained at a predetermined reduced pressure. The axial position of this landed valve relative to the resilient means being controlled by means of an electric actuator as a function of engine operation whereby to trim movement of the control piston.</p> |
