High pressure collecting chamber with integrated pressure multiplication element

#The present invention relates to a high pressure collecting chamber with integrated pressure multiplication element.

#In fuel injection systems with the use of direct injection internal combustion engines, high pressure collecting chambers (common rails) are utilized. The high pressure collecting chambers serve as a pressure storage for all injectors provided on a direct injection internal combustion engine, to damp pressure pulsations in the fuel injection system. The pulsations are caused on the one hand by the high pressure pump and on the other hand by opening of each injector during the injector phase in the injection system. With increased injection quantities, the pressure in the high pressure injecting chamber (common rail) remains at a high level, so that high pressure can act in the individual injectors of the internal combustion engine.

#German patent document DE 197 01 879 A1 discloses a fuel injection device for internal combustion engines. The fuel injector for internal combustion engines disclosed in this reference includes a high pressure collecting chamber (common rail) jointly fillable with fuel by a high pressure pump, which is connected via injection lines with injection valves extending into the combustion chamber of the internal combustion engine to be supplied. The opening and closing movements of the injection valves are controlled each by an electrically-controlled control valve, wherein the control valve can be formed as a 3/2-way valve, which connects a high pressure passage open into an injection opening of the injection valve, with the injection line or a release line. A hydraulic working chamber which is fillable with fuel under high pressure is provided at the control valve member of the control valve. It is controllable for adjusting the adjusted positions of the control valve member in a release passage.

#The single FIGURE of the drawings is a view showing a section through a multiplication piston integrated in a high pressure collecting chamber, wherein a nozzle holder combination is placed on the lower side of the high pressure collecting chamber.

#A high pressure collecting chamber 1 as shown in FIG. 1 extends in an upper region substantially symmetrical to its axis 4. Individual pressure conversion or multiplication elements 6 can be integrated in its wall 2 at a certain distances from one another. At the upper side of the high pressure collecting chamber 1 (common rail) it can be closed by a closure 3 which simultaneously allows an access to inserts located inside the high pressure collecting chamber 1. In the section shown in FIG. 1 the cross-section extends directly through the high pressure collecting chamber 1 in a region in which a piston-shaped pressure multiplication element 6 is vertically guided rotation-symmetrically to the axis of symmetry 5.

#The piston-shaped pressure conversion or multiplication element 6 which is movable vertically upwardly and downwardly in the vertical direction inside a support region 27 of the high pressure collecting chamber 1 is provided at its upper side with a disc-shaped support surface 9. It serves as a support surface for a spring element 10 which surrounds the piston-shaped pressure multiplication element 6 in its upper diameter region. The spring element 10 preferably is formed as a spiral spring. It is supported at an inner side of the wall 2 of the high pressure collecting chamber 1 in the region of an abutment surface 12 and pre-tensions the piston-like pressure multiplication element 6 inside the high pressure collecting chamber 1. An opening 7 is provided in the upper region of the piston-shaped pressure multiplication element 6. A vertically downwardly extending opening 8 extends from the opening 7. A lower diameter portion is connected to the upper diameter portion of the piston-shaped pressure multiplication element 6. The opening in the support 27 of the high pressure collecting chamber 1 represents a lower guiding surface 29 for the piston-shaped pressure multiplication element 6 which is movable vertically upwardly and downwardly in the support 27 of the high pressure collecting chamber 1.

#A control chamber 13 is limited in the housing of the high pressure collecting chamber 1 between the upper diameter region of the piston-shaped pressure multiplication element 6 and its lower diameter region. The control chamber 13 is pressure unloaded by a control module 18 which is laterally flanged on the support 27 of the high pressure collecting chamber 1. The control module 18 includes an opening which opens into the ring-shaped control chamber 13 in the support 27 of the high pressure collecting chamber 1. A discharge opening 14 of the control chamber 13 is closed and opened by a ball-shaped closing element 15. When an actuator 17 is supplied with power, the ball-shaped closing element 15 is pressed either to its seat surface 16 in the control module 18 or is withdrawn from it.