Injection compensator for fuel injection pump

摘要

A diaphragm (38) controls a position of a control sleeve (14) relative to a plunger or piston (16) in response to a pressure differential between a pressure chamber (42) and a control chamber (46) which are defined by the diaphragm (38). The pressure chamber (42) is communicated to an atmospheric pressure or a boost pressure while the control chamber (46) is selectively communicated to a source of vacuum supply through a first check valve (62) and to the atmosphere through a second check valve (58). The first and second check valves open when the pressure inside the control chamber is higher and lower than a reference level, respectively, thereby maintaining the pressure within the control chamber (46) substantially at the reference level to promote an accurate control of the control sleeve (14).