Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
  • F02M51/04—Pumps peculiar thereto
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
  • F02M63/06—Use of pressure wave generated by fuel inertia to open injection valves

Definitions

• the invention relates to a fuel injection device that operates according to the solid-state energy storage principle, in particular for two-stroke engines according to the preamble of claim 1.
• Such fuel injection devices are described in EP 0 629 265, in particular with reference to FIGS. 13 to 19. They work according to the so-called pump-nozzle system with pressure surge injection, whereby an initial accelerated partial stroke of an anchor acting as a delivery piston and axially guided on one side with an electromagnetically driven injection pump is provided, in which in the pump system a displacement of the fuel delivered without pressure build-up the fuel liquid takes place.
• the delivery piston or the armature absorbs and stores kinetic energy, the fuel displaced thereby having a predetermined flow space available, which is ensured by a fuel circuit in the pump system.
• the delivery piston Due to a sudden predetermined interruption of the fuel circuit during the resistance-free forward stroke of the delivery piston, caused by a valve device arranged in the armature or in the delivery piston and actuated by the armature movement, and due to the subsequent movement of the delivery piston, the delivery piston releases its stored kinetic energy. abruptly from the partial fuel quantity which is located in a closed space area of the circuit space - the so-called pressure space - formed or separated by the circuit interruption - between the delivery piston or in the delivery piston and an injection nozzle, for example, which is closed in a spring-loaded manner.
• the sudden pressure build-up in the fuel to, for example, 60 bar causes one Opening the injection nozzle and injecting fuel through the injection nozzle into a combustion chamber of an internal combustion engine for an extremely short time of, for example, one thousandth of a second.
• the control 6 for optimizing the pump-nozzle system takes place electronically via e.g. a microprocessor that controls the injection timing and the amount of fuel, e.g. with a temperature sensor 7, a throttle valve potentiometer 8 and a crank angle sensor 9, the injection timing is determined depending on the load.
• the microprocessor expediently also controls the ignition system 10 of the piston-cylinder unit of the engine which is supplied with fuel by the pump-nozzle system.
• the fuel circulation space is formed by a pressure chamber and a delivery piston or armature space, the pressure chamber being the partial space area separated from the pressure space by a standing pressure valve, in which the kinetic on the fuel Energy of the armature is transmitted and the armature space is the subspace area into which the fuel that is displaced without resistance can flow during the accelerated partial stroke.
• the armature space can be connected to a fuel flooding or flushing device via a housing bore, so that fuel is injected by the armature during the injection activity and / or during the starting phase of the pump or the motor Partial area can be transported.
• a fuel flooding or flushing device via a housing bore, so that fuel is injected by the armature during the injection activity and / or during the starting phase of the pump or the motor Partial area can be transported.
• the object of the invention is to largely avoid the penetration of gas bubbles into the pressure chamber and in particular also the formation of gas bubbles in the pressure chamber of the pump-nozzle systems described at the outset.
• the invention accordingly provides, in particular, a pressure chamber in which the energy stored in the armature or in the conveying piston element is transmitted to the fuel, the pressure chamber being formed separately from the armature space or armature area by the arrangement of the valve which interrupts the displacement without resistance outside the armature space .
• the pressure chamber is freely accessible, so that it can be provided for further cooling, for example with cooling fins and / or directly with a fuel supply line, so that there is only "fresh" and thus cool fuel in the pressure chamber.
• the pressure chamber can be of small volume, so that there is always only little fuel in the pressure chamber and thus the risk of a high proportion of bubbles is reduced.
• the double or double-sided axial guidance of the armature leads to the reduction of z. B. by tilting the armature, which were previously possible, caused friction and thus to reduce heat.
• the double-sided axial anchor guide does not only help in connection with the problems described above. In other known embodiments of the pump-nozzle systems, it also leads to simplification of the spatial shape, to simplification and thus also to a more uniform design and to simplification. Chung the assembly of the armature or the pump and in particular also to reduce radial vibrations of the armature, which in the known pump-nozzle systems due to the only one-sided axial guidance and due to the unavoidable or necessary excessive friction-reducing play between the armature jacket and cylinder wall of the pump are possible and impair the reproducibility of the injection processes.
• FIG. 1 schematically shows the arrangement of a fuel injection device in a single-cylinder two-stroke engine
• FIG. 2 shows schematically in longitudinal section a first embodiment of an injection pump according to the invention
• FIG. 3 in cross section an armature of the injection pump shown in Fig. 2;
• FIG. 4 shows in cross section a valve body of the injection pump shown in FIG. 2;
• FIG. 5 schematically shows in longitudinal section a second embodiment of an injection pump according to the invention.
• Fig. 6 shows schematically in longitudinal section a parking pressure valve.
• the fuel ice spray device according to the invention for internal combustion engines is designed as an electromagnetically driven reciprocating piston pump 1, which works according to the energy storage principle, so that fuel is injected into the internal combustion engine with short pressure surges.
• the reciprocating piston pump 1 has an essentially elongated cylinder-shaped pump housing 15 with an armature bore 16, a valve bore 17 and a pressure chamber bore 18, each of which is introduced one after the other in the pump housing 15 and extends through the entire pump housing 15 Make passage.
• the armature bore 16 is arranged behind the valve bore 17 in the injection direction and the pressure chamber bore 18 is arranged in front of the valve bore 17 in the injection direction.
• the bores 16, 17, 18 are arranged concentrically to the longitudinal axis 19 of the pump housing 15, the armature bore 16 and the pressure chamber bore 18 each having a larger inner diameter than the valve bore 17, so that the armature bore 16 and the valve bore 17 pass through a first ring stage 21 and the valve bore 17 and the pressure chamber bore 18 are separated from each other by a second ring stage 22.
• the armature bore 16 delimits an armature space 23 in the radial direction, in which an approximately cylindrical armature 24 is arranged such that it can move back and forth in the longitudinal axis direction.
• the armature space is delimited in the axial direction to the front by the first ring step 21 and to the rear by a front end face 25 of a cylindrical sealing plug 26 which is screwed into the end of the armature bore 16 which is open to the rear in the ice injection direction.
• the armature 24 is formed from an essentially cylindrical body with a front and rear end face 28, 29 and a lateral surface 30 in the injection direction. Material is removed from the rear end surface 28 to approximately the longitudinal center of the armature 24 at the armature circumferential area, so that the armature 24 has a conical surface 31 that extends from the rear to the front.
• the armature 24 is inserted with play between its outer surface 30 and the inner surface of the armature bore 16, so that when the armature 24 moves back and forth in the armature bore 16, it touches the inner surface of the armature bore 16 only when the armature 24 is tilted , whereby the friction between the armature 24 and the armature bore 16 is kept low.
• the provision of the conical surface 31 on the armature 24 further reduces the contact and thus the friction surface, as a result of which the friction between the armature 24 and the inner surface of the armature bore 16 and thus also the heat development is further reduced.
• the armature 24 is connected in the region of its lateral surface 30 with at least one, preferably two or more, in the longitudinal axis direction. running grooves 32 provided.
• the armature 24 has a cross-sectional shape (FIG. 3) with two laterally arranged semicircular elements 24a and with two wide, flat grooves 32 in the area between the semicircular elements 24a.
• a continuous bore 33 is made centrally on the armature 24 in the longitudinal axis direction.
• a delivery piston tube 35 is inserted, which forms a central passage space 36.
• a plastic ring 37 is seated on the front end face 29 of the armature 24 and is penetrated by the delivery piston tube 35.
• An anchor spring 38 is supported on the plastic ring 37 and extends to a corresponding corresponding bearing ring 39. This bearing ring 39 is seated on the first ring stage 21 in the armature bore 16.
• the delivery piston tube 35 is non-positively connected to the armature 24.
• the unit consisting of feed piston tube 35 and armature 24 is referred to below as feed piston element 44.
• the conveying piston element 44 can also be formed in one piece or in one piece.
• valve bore 17 there is a form-fitting guide tube 40 which extends rearward into the armature space 23 in the area inside the spiral spring 38.
• annular web 41 At the front end of the guide tube 40 in the injection direction, an outwardly projecting annular web 41 is provided, which is supported on the second annular step 22 to the rear.
• the ring web 41 does not extend radially to the inner surface of the pressure chamber bore 18, so that a narrow, cylindrical gap 42 is formed between the ring web 41 and the pressure chamber bore 18.
• the guide tube 40 is secured against an axial displacement to the rear by the ring web 41.
• the delivery piston tube 35 which is non-positively connected to the armature 24, extends forwards into the guide tube 40 and backwards into an axial blind bore 43 of the sealing plug 26, so that the delivery piston tube 35 both at its direction of injection front end 45 and at its rear end 46 is guided.
• This two-sided guide at the ends 45, 46 of the elongated delivery piston tube 35 guides the delivery piston element 44 without tilting, so that undesired friction between the armature 24 and the inner surface of the armature bore 16 is reliably avoided.
• a valve body 50 is axially displaceably mounted, which forms an essentially cylindrical, elongated, peg-shaped solid body with a front and rear end face 51, 52 and a jacket surface 53.
• the outside diameter of the valve body 50 corresponds to the clear width of the passage in the guide tube 40.
• An annular web 54 is provided on the lateral surface 53 of the valve body 50 and is arranged approximately at the end of the front third of the valve body 50.
• the ring web 41 of the guide tube 40 forms an abutment for the ring web 54 of the valve body 50 in the rest position of the valve body 50, so that it cannot be moved further back.
• the valve body 50 is provided on its circumference with three grooves 55 running in the longitudinal axis direction (FIG. 4).
• the ring web 54 is interrupted in the area of the grooves 55.
• the rear end face 52 of the valve body 50 is conical at its edge region and interacts with the end face of the front end 45 of the delivery piston tube 35.
• the three-dimensional shape of the front end 45 of the delivery piston tube 35 is adapted to the rear end face 52 of the valve body 50, in which the inner edge of the delivery piston tube 35 is chamfered and the wall of the delivery piston tube 35 is somewhat worn away on the inside.
• the delivery piston tube 35 thus forms with its front end 45 a valve seat 57 for the valve body 50. If the valve body 50 rests with its rear end face 52 on the valve seat 57, the passage through is in the area of the lateral surface of the valve body 50 introduced grooves 55 blocked.
• the projecting region of the valve body 50 is surrounded by a pressure chamber body 60, which consists of a cylinder wall 61 and a front end wall 62, a hole or a bore 63 being made centrally in the end wall 62.
• the pressure chamber body 60 is inserted with its cylindrical wall 61 in a form-fitting manner in the pressure chamber bore 18, with its end faces 64 lying on the free end of the cylinder wall 61 being arranged abutting the outwardly projecting annular web 41 of the guide tube 40, with radial pressure in the pressure chamber body 60
• Through bores 65 are provided which create a connection between the pressure chamber 66 and the fuel supply bore 76.
• the pressure chamber body 60 delimits with its interior a pressure chamber 66 into which the valve body 50 can immerse and pressurize the fuel in the pressure chamber 66.
• the pressure chamber At its rear region in the injection direction, which extends approximately over half the length of the pressure chamber body 60, the pressure chamber has a larger clear width than in the front region.
• the larger clear width in the rear area is dimensioned such that the valve body 50 with its ring web 54 and a slight play can dip into the pressure chamber 66
• the clear width of the front area is dimensioned such that only for the ring web 54 the front area of the valve body 50 and a helical spring 67 surrounding this area is sufficient space.
• the pressure chamber 66 is made only slightly larger than the space required during the injection process of the valve body 50.
• the coil spring 67 is seated with an end of the inside of the Stirn ⁇ wall 62 of the pressure chamber body 60 and rests with its other end on the valve body 50 and in particular on the annular rib 54, so that they d # e ⁇ valve body 50 and presses apart the pressure chamber body 60th
• the pressure chamber body 60 is forward in the injection direction axially fixed by a connector 70 which is screwed into the forward open end of the pressure chamber bore 18.
• the An ⁇ connection piece 70 limits the position of the pressure chamber body 60 in the axial direction to the front, so that the coil spring 67 biases the valve body 50 to the rear.
• the connection piece is designed with an opening 71 for connecting a fuel delivery line 72 (FIG. 1).
• the connecting piece 70 has a bore 73 which is continuous in the longitudinal axis direction and in which a standing pressure valve 74 is accommodated.
• the standing pressure valve is preferably arranged adjacent to the pressure chamber body 60.
• the pressure chamber body 60 is provided on its outer surface with an annular groove 68, in which a plastic sealing ring 69 is mounted, which seals the pressure chamber body 60 against the inner surface of the pressure chamber bore 18.
• a fuel supply opening 76 is made in the area of the pressure chamber bore 18 on the pump housing 15 so that it can communicate with the bores 65 in the pressure chamber body 60.
• the fuel supply opening 76 is surrounded by a holder 77 for a fuel supply valve 78 which is screwed into the holder 77.
• the fuel supply valve 78 is designed as a one-way valve with a valve housing 79.
• the valve housing 79 has two axially aligned bores 80, 81, the bore 80 on the pump housing side having a larger inner diameter than the bore 81, so that an annular step is formed between the two bores which forms a valve seat 82 for a ball 83.
• the ball 83 is preloaded against the valve seat 82 by a spring 84, which is supported in the area around the fuel supply opening 76 on the pump housing 15 in the bore 80, so that the fuel 83 supplied from outside by pressure is the ball 83 from the valve seat 82 lifts so that the fuel is supplied through the bore 80 and the fuel supply opening 76 into the pressure chamber bore 18.
• a passage extends from the pressure chamber 66 through the grooves 55 of the valve body 50, the distance between the valve seat 57 of the delivery piston tube 35 and the rear end face 52 of the valve body 50 and the passage space 36 of the delivery piston tube 35 into the blind hole 43 of the sealing plug 26
• the blind hole or blind bore 43 is arranged to run in the longitudinal axis direction and opens into the armature space 23, the blind hole 43 extending over approximately two thirds to three quarters of the length of the sealing plug 26.
• One, preferably two or more long bores 88 extends from the rear area of the blind hole 43 to the peripheral area 89 of the front end face 25 of the sealing plug 26, so that a communicating connection is established between the armature space 23 and the blind hole 43.
• an outwardly leading bore 90 is made as a fuel drain opening.
• the bore 90 is extended on the outside through a connecting piece 91 for connecting a fuel return line 92 (FIG. 1).
• the cylindrical sealing plug 26 has a circumferential, outwardly projecting annular web 93 on its outer surface.
• the ring web 93 also serves, among other things, for the axial fixing of a locking ring 94 encompassing the pump housing 15 on the outside or a coil housing cylinder 95 arranged directly adjacent to the locking ring 94.
• the locking ring 94 forms two legs 96, 97, arranged at right angles to one another in cross section. one leg 96 abuts the outside of the pump housing 15 and the other leg 97 projects outward and abuts the coil housing cylinder.
• the bobbin case cylinder 95 consists of a cylinder wall 98 and a cylinder base 99, which is connected laterally to the cylinder wall 98 and points inwards, and has a hole so that the bobbin case cylinder 95 faces the bobbin case 15 with the cylinder base 99 from behind pointing towards the rear until the cylinder wall 98 is attached to one of the coil housing 15 abuts vertically outwardly projecting housing wall 100 and thus delimits an annular chamber 101 with an approximately rectangular cross section for receiving a coil 102.
• the coil housing cylinder 95 and the locking ring 94 are thus clamped between the housing wall 100 and the ring web 93 of the sealing plug 26 and fixed in their axial position.
• the leg 96 of the locking ring 94 is chamfered on the inner edge of its end face, a sealing ring 103, such as, for example, between the bevel formed therein and the ring web 93. B. a 0 ring is clamped.
• the coil 102 is approximately rectangular in cross-section and is cast into a support body cylinder 104 with a U-shaped cross section by means of epoxy resin, so that the coil 102 and the support body cylinder 104 form a one-piece coil module.
• the supporting body cylinder 104 has a cylinder wall 105 and two side walls 106, 107 which protrude radially from the cylinder wall 105 and delimit the space for the coil 102, the cylinder wall 105 extending laterally beyond the rear side wall 106 extends so that its end face 108, the end face 109 of the side walls 106, 107 and the inner surfaces of the cylinder wall 106 and the front side wall 107 bear in a form-fitting manner in the annular chamber 101.
• a material 110 with low magnetic conductivity e.g. Copper, aluminum, stainless steel, introduced to avoid a magnetic short circuit between the coil 102 and the armature 24.
• FIG. 5 A second exemplary embodiment of the injection pump according to the invention is shown in FIG. 5.
• the reciprocating pump 1 according to the second exemplary embodiment has essentially the same structure as the reciprocating pump 1 described above, so that parts with the same spatial shape and the same rather function with the same reference numerals.
• the reciprocating piston pump 1 according to the second exemplary embodiment has a shorter length than the reciprocating piston pump according to the first exemplary embodiment, the shortening being achieved essentially by using a ball 50a as a valve body.
• the ring web 41 of the guide tube 40 forms an abutment in the rest position for the ball 50a, so that it cannot be moved further back.
• the ring web 41 is formed with an annular ball seat 41a adapted to the spherical shape, so that the ball 50a abuts the ring web 41 in some areas in a form-fitting manner.
• the ball 50a has a smooth surface, which is why grooves 41b are introduced into the ball seat 41a, which connects the pressure chamber 66 to the gap between the valve seat 57 of the delivery piston tube 35 and the surface of the ball 50a when this is at a distance from the latter Valve seat 57 is arranged.
• the provision of the grooves 41b enables flushing of the pressure chamber 66.
• the sealing plug 26a of this exemplary embodiment has a central first bore 120 which extends from the front end face 25 and in which the delivery piston tube 35 is guided and which corresponds to the blind hole 43 of the sealing plug 26 of the first exemplary embodiment.
• the first bore 120 opens into a second bore 121 of the sealing plug 26a.
• the bores 120, 121 are arranged concentrically to the longitudinal axis 19 of the pump housing 15 or the sealing plug 26a.
• the second bore 121 extends up to the rear end face 122 of the sealing plug 26a and is provided with an internal thread for receiving a connecting piece 91a for connecting a fuel return line 92.
• the flow path for flushing through the delivery piston tube 35 thus extends from the fuel supply valve 78 into the pressure chamber 66 through the grooves 41b into the gap between the valve seat 57 and the ball 50a and through the passage space 36 of the delivery piston tube 35 in the bore 121 or through the connecting piece 91a into the fuel return line 92.
• This flow path therefore does not lead through the armature space 23.
• a cross-flow path is provided for flushing the armature space 23, which has a cross-flow bore 125 which extends between the bore 81 of the valve housing 79 and the armature space 23 and connects these to one another.
• the bore 81 of the valve housing 79 lies outside of the fuel supply valve 78, so that the fuel supplied is led directly into the armature space 23 without any constrictions.
• the fuel flows through the bores 88 in the sealing plug 26a into the second bore 121, in which the connecting piece 91a is seated, and through the connecting piece 91a into the fuel return line 92.
• the cross-flow path thus forms a kind of bypass to the flow ⁇ mungsweg through the passage space 36 of the delivery piston tube 35th
• the cross-flow path is advantageous in the case of strong heat development in the armature space 23, since the armature space 23 is flushed with cool fuel, the armature space 23 being flushed with a high throughput, since the cross-flow path has no constrictions, e.g. Has valve or groove passages that would hinder the flow.
• the provision of the cross flow path enables the armature chamber 23 to be flushed without an additional fuel pump, which puts the supplied fuel under a pre-pressure, since fuel is also conveyed into the cross flow path due to the suction effect of the reciprocating piston pump 1.
• the armature 24 is pressed backward by the spiral spring 38 against the sealing plug 26, against which it rests with its rear end face 49. This is the starting position of the armature 24, in which the delivery piston tube 35 is arranged with its valve seat 57 at a distance s v from the rear end face 52 of the valve body 50.
• a fuel at a pre-pressure is supplied from the fuel tank 111 by means of a fuel pump 112 and a fuel supply line 113 through the fuel supply valve 78 into the pressure chamber 66.
• the fuel flows through the grooves 55 made in the jacket area of the valve body 50, through the guide tube 40 into the gap between the valve seat 57 of the delivery piston tube 35 and the rear end face 52 of the valve body and through the passage space 36 of the delivery piston 35 into the blind hole 43 of the sealing plug 26.
• the fuel under pressure flows through the bores 88 of the sealing plug 26 and floods the armature space, the regions of the armature space in front of and behind the armature 24 the grooves 32 made in the armature 24 are communicatively connected to one another so that the entire armature space is filled with fuel.
• the fuel is fed back into the fuel tank 111 through a fuel return line 92.
• the admission pressure generated by the fuel pump 112 is greater than the pressure drop that arises in the flow path, so that a continuous flushing of the reciprocating piston pump 1 is ensured, and is lower than the passage pressure of the auxiliary pressure valve 74, so that in the initial position of the delivery piston element 44, no fuel enters the combustion chamber 4 is funded.
• the armature 24 is moved forward in the impact or injection direction by the magnetic field generated in this way.
• the movement of the armature 24 and the delivery piston tube 35 connected to it in a non-positive manner acts during a forward stroke over the length s v (corresponds to the distance between the valve seat 57 of the delivery piston tube 35 and the rear end face 52 of the valve body 50 in the starting position) only the spring force of the spring 38 counter.
• the spring force of the spring 38 is designed so soft that the armature 24 is moved almost without resistance, but is still sufficient for returning the armature 24 to its starting position.
• the armature 24 "floats" in the pressure chamber 23 filled with fuel, the fuel being able to flow back and forth as desired between the areas in front of and behind the armature 24 in the armature space 23, so that no pressure opposing the armature 24 is built up.
• the delivery piston element 44 consisting of armature 24 and the delivery piston tube 35, is thus continuously accelerated and stores kinetic energy.
• the delivery piston element 44 strikes with the valve seat 57 on the rear end face 52 of the valve body 50, so that the latter is suddenly pushed forward. Since the delivery piston tube 35 now rests with its valve seat 57 on the rear end face 52 of the valve body 50, the flow path is from the pressure chamber to the passage space 36 of the delivery piston tube 35 interrupted so that the fuel can no longer escape from the pressure chamber 66 to the rear. The fuel is thus displaced by the advancing movement of the valve body 50 in the pressure chamber 66, whereby it is pressurized. The fuel supply valve 78 is now closed because a pressure builds up in the pressure chamber and in the bore 80 of the fuel supply valve 78 which is greater than the pressure at which the fuel is supplied by the fuel pump.
• the stand pressure valve 74 then opens, so that the fuel in the delivery line between the injection nozzle 2 and the reciprocating pump 1 is compressed to a predetermined pressure, which is, for example, 60 bar and is determined by the passage pressure of the injection nozzle 2 is.
• a predetermined pressure which is, for example, 60 bar and is determined by the passage pressure of the injection nozzle 2 is.
• the injection nozzle 2 injects the fuel directly into the cylinder 5 of the internal combustion engine, the fuel being atomized finely through the nozzle 2 due to the high pressure which is achieved with the injection device according to the invention.
• the standing pressure valve 74 is a non-return valve, such non-return valves conventionally having a bore in a valve seat against which a rigid valve body is pressed by a spring.
• the conventional parking pressure valves 74 close the supply line to the fuel delivery line 72 very quickly and safely. In this case, a standing pressure remains in the fuel delivery line 72, which is often only slightly less than the opening pressure of the injection nozzle 2.
• the pressure in the fuel delivery line 72 can change as a result of temperature fluctuations, so that the injection nozzle opens and fuel enters the combustion chamber at an indefinite point in time, as a result of which the pollutant values in the exhaust gases are increased considerably.
• the standing pressure valve 74 in the fuel delivery line 72 should maintain a certain permanent pressure level of approximately 5 to 10 bar in order to prevent vapor bubbles from forming.
• the object is achieved by a standing pressure valve with the features of claim 17.
• the supply line to the fuel delivery line is closed quickly and securely and a stand pressure in the fuel delivery line is achieved which takes up a level which is significantly below the passage pressure of the injection nozzle and above the level necessary to avoid vapor bubble formation.
• the standing pressure valve 74 has a flat, elastic membrane 200 as a valve body, which is pressed against a valve seat device 201 by a spring 202 (FIG. 6).
• auxiliary pressure valve 74 In the open position of the auxiliary pressure valve 74, fuel is delivered from the auxiliary pressure valve outside or the pressure chamber 66 under high pressure in the direction of the injector 2, the diaphragm 200 being lifted off the valve seat 201. The same pressure occurs on both sides of the membrane 200, so that the pressure applied to both flat sides of the membrane 200 is in equilibrium.
• the membrane takes on a flat shape.
• the spring 202 presses the membrane 200 onto the valve seat 201, the parking pressure valve being closed at a predetermined closing pressure. If the pressure on the outside of the auxiliary pressure valve decreases further, the diaphragm 200 becomes outward from the pressure prevailing on the spring side to the pressure chamber 66 arched so that the fuel in the fuel delivery line 72 can expand or spread somewhat, thereby lowering its pressure level.
• a further pressure drop can occur under the closing pressure of the auxiliary pressure valve 74.
• pressure fluctuations occurring in the fuel delivery line 72 can be compensated for by the elasticity of the membrane 200, so that an unintentional increase in pressure in the fuel delivery line 72 and thus an unintentional opening of the injection nozzle is avoided.
• the standing pressure valve 74 is preferably designed such that the spring 202 acts on the diaphragm 200 in a region which lies axially within the support of the diaphragm 200 on the valve seat 201, so that the diaphragm 200 is at the valve seat 201 by the spring action of the spring 202 is generally arched.
• the membrane 200 can be formed from rubber or metal, a rubber membrane expediently being surrounded by a metal frame stiffening the membrane.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)

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• 1995
  • 1995-04-28 DE DE1995115782 patent/DE19515782A1/de active Pending
• 1996
  • 1996-04-24 DE DE59602722T patent/DE59602722D1/de not_active Expired - Fee Related
  • 1996-04-24 ES ES96912036T patent/ES2136402T3/es not_active Expired - Lifetime
  • 1996-04-24 AU AU55021/96A patent/AU692097B2/en not_active Ceased
  • 1996-04-24 JP JP8532166A patent/JP3025309B2/ja not_active Expired - Lifetime
  • 1996-04-24 AT AT96912036T patent/ATE183285T1/de active
  • 1996-04-24 WO PCT/EP1996/001715 patent/WO1996034196A1/fr active IP Right Grant
  • 1996-04-24 KR KR1019970707614A patent/KR100326625B1/ko not_active IP Right Cessation
  • 1996-04-24 US US08/945,976 patent/US6401696B1/en not_active Expired - Lifetime
  • 1996-04-24 CA CA002218695A patent/CA2218695C/fr not_active Expired - Fee Related
  • 1996-04-24 EP EP96912036A patent/EP0823019B1/fr not_active Expired - Lifetime

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