摘要:
A pump/nozzle unit having an injection nozzle installed at at least approximately right angles to the longitudinal axis (A) on the pump housing of the piston injeciton pump. The injection pump is supported with a support face, which embodies its most extreme axial extension, on a support bearing located on the cylinder head of the engine. The support face is embodied by an outwardly pointing end face of a counterpart piston which is inserted into the pump cylinder in an extension of the longitudinal axis (A) and, with an inner end face, seals off the pump work chamber in a pressure-tight manner. As a result, the pumping forces resulting from the fuel which is placed under pressure in the pump work chamber are kept from affecting the pump housing and intercepted at a location on the cylinder head which is remote from a receiving bore for the injection nozzle.
摘要:
A fuel injection apparatus which the termination of the effective pump supply stroke is effected by exposing a relief conduit with the aid of a valve having for instance a control edge, whereupon a highly pressurized fuel flows out via the relief conduit and is directed into a pressure chamber defined by a rear face of a pressure valve closing member. The pressure valve closing member is located in a connection with a fuel injection line that leads from the pump work chamber to the fuel injection valve and is acted upon by a valve spring to effect closing of this injection line. The impact of fuel that reaches the pressure chamber via the releif conduit reinforces a fast closure of the pressure valve closing member at the end of injection, which leads to an abrupt termination of an injection cycle. In addition, or altenatively, the fuel injection valve closing member can also be acted upon by the impact of fuel diversion.
摘要:
The unit fuel injector has a pump piston driven at a constant stroke length, which pumps fuel at injection pressure to an injection nozzle as long as an electrically actuated overflow valve blocks the flow of the fuel flowing from the pump work chamber to a low-pressure chamber via an overflow conduit. The overflow valve is inserted between a first section which communicates continuously with the pump work chamber and a second section leading to the low-pressure chamber of the overflow conduit and is secured to a housing part laterally projecting from the pump housing. The first section of the overflow conduit comprises a connecting bore leading away from the pump work chamber, a control conduit controlled by the overflow valve, and a transverse conduit connecting these two. The transverse conduit extends from the housing side remote from the projecting housing part to the control conduit, crossing through the cylinder bore and in every stroke position of the pump piston is sealed off, without additional sealing means, by the jacket face of the pump piston. The unit fuel injector is particularly suitable for high-pressure injection in Diesel engines.
摘要:
The fuel injection pump of this invention proposes at least one cylinder, a piston, a drive rod, a guide sleeve for the drive means, a guide conduit embracing the guide sleeve, a restoring spring for the drive rod and piston, said piston being designed to execute a suction stroke under the influence of the restoring spring. The injection pump also comprises a locking mechanism comprising a bearing which extends into two recesses. The one recess is in the form of an annular groove located in the guide conduit. The other recess is a slot formed in the guide sleeve in its longitudinal direction. The locking mechanism prevents the guide sleeve together with the rod and piston from falling out after the injection pump has been assembled. The locking mechanism is inexpensive and easy to assemble because it requires only a single bearing in addition to already existing components of the injection pump.
摘要:
The pump/nozzle unit for a fuel injection system is disclosed which has a pump piston that is driven via a drive tappet and is rotatable by means of a regulating sleeve. The regulating sleeve, provided with a radially protruding control lever arm, is axially secured in its installed position by means of a guide bushing. The guide bushing includes a guide part for the drive tappet and a radially protruding flange, which is secured to the pump housing by at least one holder passing through an oblong slot on the flange of the guide bushing. A recess in the form of a circular segmented ring is cut out of the guide bushing for the passage therethrough of the control lever arm. By rotating the guide bushing within a range limited by the oblong slot a lateral limiting edge of the recess is adjustable into a position in which the pump piston, with the control lever arm resting on the limiting edge assumes a rotational position associated with a fixed supply quantity. As a result, no further additional or full-load stop device is necessary and mounting of the drive unit and pump assembly on the engine are facilitated.
摘要:
A pump/nozzle unit having a piston injection pump and an injection nozzle which includes a pump piston that is driven via a drive tappet and is rotatable via a regulating sleeve. The regulating sleeve is inserted into a recess on the end face of the pump housing and is axially secured in its installed state by means of a guide bushing. The guide bushing comprises a guide part for the drive tappet and a flange radially protruding beyond the outer diameter of the tappet spring, the flange being secured on the pump housing by a holder mechanism. The forces exerted upon the pump/nozzle unit during operation are absorbed by a securing arrangement. The drive assembly unit, including the drive tappet, tappet spring, guide bushing and pump piston, which is held together by a loss-preventing device, can be mounted outside the pump/nozzle unit and removed as a unit for purposes of mounting and inspecting the regulating sleeve, and even in the demounted or disassembled state of the pump/nozzle unit this drive assembly unit remains joined to the pump/nozzle unit by the holder mechanism.
摘要:
The fuel injection system has at least two electrically actuated control valves for controlling the fuel injection; the control valves are each connected via electric lines to an electric control unit. In the fuel injection system, terminal elements for connection of the electric lines are provided. For a first of the control valves, a structural element is provided, on which the terminal elements for all the control valves are disposed, and which can be secured to a housing part of the fuel injection system. At least one electric connecting line from the terminal elements to the second control valve disposed inside a housing part of the fuel injection system is integrated with the structural element.
摘要:
A fuel injection device for fuel-injected internal combustion engines, in particular to a unit fuel injector, in which the control of the onset and end of supply is effected by means of a magnet valve incorporated between a low-pressure circuit and a work chamber of a pump piston; a scavenging bore, connectable to the work chamber, of a scavenging line that communicates with a low-pressure chamber or the tank is provided. A delivery line for delivering the fuel from the magnet valve to the work chamber of the pump piston discharges directly into the pump work chamber and communicates with it in a permanently open fashion. The arrangement is selected such that the mouth of the scavenging bore is located in a region of the guide bore of the pump piston which is overridden by the pump piston in all the positions of the pump piston, and this mouth is connectable at least indirectly to the delivery line and the work chamber of the pump piston, via a recess of the piston, in the region of the top dead center position of the piston.
摘要:
The injection pump includes a pump cylinder, a pump piston moving into it and a hydraulic device for adjusting the instant of injection. The adjusting device has an adjusting cylinder, which is directed parallel to the pump cylinder and is accommodated in the housing of the injection pump, and adjusting piston and a restoring spring and adjusts a control sleeve, which opens the pump piston provided with at least one control recess in the longitudinal direction of the pump piston. This orientation and disposition of the adjusting cylinder effects a space-saving and inexpensive design of the injection pump and improves the precision of adjustment. The adjusting piston and the control sleeve may be directed coaxially and embodied as a single component, as a result of which a further space saving and increase in adjustment precision are attained.
摘要:
The invention relates to an injector for injecting fuel into combustion chambers. According to the invention, a valve piston of a control valve is provided with low pressure on both faces thereof. The valve piston is arranged in a valve chamber hydraulically connected to a control chamber and is guided inside a sleeve received in the valve chamber. The valve chamber contains a spring supported on one end against the sleeve and on the other end on the valve piston such that the spring presses the valve piston onto a valve seat and the sleeve onto an opposing bottom surface. The valve piston diameter inside the sleeve corresponds to the effective valve piston diameter at the valve seat.