Method and arrangement for controlling the injection pressure of liquid fuel

Apparatus for controlling the injection pressure for fuel through a nozzle for combustion in an engine comprising injecting means for injecting said fuel at a predetermined injection pressure through said nozzle, a primary control valve having open and closed positions for maintaining said pressure during injecting of said fuel when said primary control valve having open and closed positions for maintaining said pressure during injecting of said fuel when said primary control valve is in said closed position, and a secondary control valve associated with said primary control valve, said secondary control valve having open and closed positions for relieving at least a portion of said pressure during said predetermined portion of said injecting of said fuel when said secondary control valve is in said open position, wherein said primary control valve comprises a housing, and including a movable valve body movable within said housing between open and closed positions, a first spring member for urging said movable valve body into said closed position, and an electromagnet for urging said movable valve body into said open position upon actuation of said electromagnet, and wherein said movable valve body includes an outer surface and an inner channel, said secondary control valve comprising a movable rod movably disposed within said inner channel of said movable valve body, said movable rod including a first end and a second end, said movable valve body including at least one aperture extending between said outer surface and said inner channel, said movable rod being movable within said inner channel between a first position wherein said movable rod blocks flow through said at least one aperture and a second position wherein said movable rod does not block flow through said at least one aperture, said first end of said movable rod being disposed at a position proximate to said electromagnet, a second spring member disposed between said second end of said movable rod and said movable valve body for urging said movable rod into said first position, said first spring member having a first stiffness and said second spring member having a second stiffness, said second stiffness being greater than said first stiffness whereby actuation of said electromagnet can urge said movable valve body into said closed position and further activation of said electromagnet can urge said movable valve body into said second position.