DE19515774A1 - Fuel-injection system e.g. for two-stroke IC engine - Google Patents

Abstract

The system operates on the solid-state energy storage principle and contains a piston pump with a feed piston element which is moved from its starting position towards a pressure chamber (66), storing kinetic energy during an approximately null resistance acceleration phase. The kinetic energy is transferred to fuel in the pressure chamber as a shock, so that a pressure step is produced to eject fuel via an injection nozzle arrangement. A second pressure chamber (66') is arranged on the opposite side of the feed piston element from the first chamber (66) so that the kinetic energy acquired as the piston moves back to its initial position is transferred to fuel in the second chamber.

Description

The invention relates to a solid-state energy storage Principle working fuel injection device 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 acting as a delivery piston, axially guided to one core of an electromagnetically driven injection pump is provided, in which in the pump system a displacement of delivered fuel without pressure build-up in the fuel liquid. During this initial partial stroke, the delivery piston or the armature absorbs kinetic energy and stores it, the fuel displaced thereby having a predetermined flow space available, which is ensured by a fuel circuit in the pump system. Due to a sudden vorbe, by means of a valve device arranged in the armature or in the delivery piston and actuated by the armature movement, the fuel circuit is interrupted during the resistance-free forward stroke of the delivery piston and due to the subsequent movement of the delivery piston, the delivery piston gives its stored kinetic energy pressure surge or abruptly to the partial fuel quantity, which is formed in a closed or formed by the circuit interruption closed space area of the cycle space - the so-called pressure chamber - between the delivery piston or in the delivery piston and a z. B. is spring-loaded closed injector. The sudden pressure build-up in the fuel on z. B. 60 bar causes an opening of the injector and an injection of fuel through the injector into a combustion chamber of an internal combustion engine for an extremely short time of, for. B. a 1,000th of a second.

These pump-nozzle systems known from EP 0 629 265 comprise an electromagnetically driven reciprocating pump 1 and the injection nozzle 2 ( FIG. 1a). These pump-nozzle systems have proven particularly useful in two-stroke engines, in which previously large amounts of pollutants were known to be muffled by flushing losses and high fuel consumption resulted from a high proportion of fuel being able to pass through exhaust passage 3 unused because overflow and exhaust passage 3 were used simultaneously in two-stroke engines are open. With the pump-nozzle systems described above, fuel consumption and pollutant emissions have now been drastically reduced. In addition, the previous uneven running of the engine, which was based on irregular ignition at low engine speeds, was almost completely prevented. The fuel is injected extremely briefly and directly into the combustion chamber 4 of a cylinder 5 , and only when the exhaust port 3 is largely closed. The control tion 6 for optimizing the pump-nozzle system is done electronically via z. B. a microprocessor that controls the injection timing and the amount of fuel, z. B. 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.

Through these pump-nozzle systems, the hydrocarbon emis drastically reduced compared to other two-stroke engines changes, at the same time the running culture, especially at low Speeds, is significantly improved. Also carbon monoxide and that Oil supplied for lubrication is used in significantly smaller quantities ejected so that such a two-stroke engine with respect to Exhaust emissions are comparable to a four-stroke engine, but the  still the two-stroke high performance with low weight having.

In the pump-nozzle systems described above, the force Material cycle space from a pressure chamber and a delivery piston ben- or anchor space formed, the pressure chamber of the by a parking pressure valve separated from the pressure chamber area is where the kinetic energy of the anchor on the fuel is transmitted and the anchor space is the subspace area, in which the fuel displaced without resistance during the accelerated partial strokes can flow.

The armature space can over the known pump-nozzle systems a housing bore with a fuel flooding or flushing communicated so that fuel during the Injection activity of the armature and / or during the start phase the pump or the motor is conveyed through this area can be. This flooding or rinsing with z. B. cool and bubble-free fuel become more in the anchor space bubble fuel removed, the anchor space and its Environment cooled and blistering due to heat and / or cavitation largely suppressed.

Under special conditions, especially when exposed to Heat on the fuel in the unit injector system during the Operation, e.g. B. by electrical energy and / or anchorage exercise or the like, bubbles can form in the Pressure room. This can affect the function of the unit injector stems and in particular affect the injection process.

It is with direct fuel injection in diesel engines known to design the injection process so that initially a first amount of fuel is injected and after a Ignition delay, a second main amount of fuel is injected, so that the diesel shock or the knocking noise of the diesel engine be significantly reduced.  

There are basically two procedures in this context known, namely the step injection and the double injection tongue. Double injection can be with two pump elements or with a very fast working pump element for two Injection can be realized. The necessary constructive So far, however, the effort has failed a practical application, especially since it was assumed that this would only knock the engine, but its fuel consumption is not reduced.

For this reason, the step injection was realized is realized by means of a pilot injector, the two Has nozzle bores that are at different pressures to open. As a result, the injection process into a pre-jet and split a main beam.

The invention has for its object a simple one to create a spray device that reduces pollutants, Saving fuel enables and independent of mixed oil satchel is.

The task is performed using a multiple injector solved the features of claim 1. The one according to the invention sprayer works on the solid-state energy storage Principle whereby large amounts of fuel are used for a short time tervalle can be injected and is double-acting forms, the injection device according to the invention a A to-and-fro movement or a thrust and recoil movement of a Delivery piston element during a work cycle both for a pre-injection by the shock movement as well for one Post-injection exploited by the recoil movement. Hereby simplifies the structure of the injector in Ver essential to two individual injection devices, in particular, the number of parts is reduced, especially if the delivery piston element is formed in one piece.

With the injection device according to the invention is thus on simple way an exact and fast double  injection realized so that an optimal force in the combustion chamber distribution of materials and reliable ignition or ignition aims to be. This reduces pollutant emissions and saved fuel. The engine can also make a difference Liche mixture qualities with regard to the combustion air ratio nisses (λ) are operated without the ignition and the Ver combustion quality affected by different air volumes be done. Different air volumes are in operation of the Engine inevitable in the cylinder.

Advantageous developments of the invention are in the sub claims marked.

The invention accordingly sees in particular a pressure chamber in the energy stored in the armature or in the delivery piston element gie is transferred to the fuel, which reflects the steady displacement interrupting valve outside the on kerraums, or spatially separated from the anchor space and anchor area is arranged arranged. This will make the anchor room generated heat is not transferred directly to the pressure chamber, whereby the heating of the compressed during the injection process Fuel and thus the risk of blistering considerably is reduced. In addition, the pressure chamber is freely accessible that for further cooling, for example with cooling fins and / or directly with a fuel supply line can, so that the pressure chamber bubble-free, cool fuel can be supplied. Furthermore, the pressure chamber can be small-volume ger be formed so that there is less fuel in the The pressure chamber is located, causing the risk of blistering is reduced.

In addition, due to the small pressure chamber at direct Only a small amount of fuel washes around the fuel supply will.

A double or double-sided axial guidance of the armature according to Claim 5 avoids frictional tilting movements of the An  kers, so that heat development can be suppressed.

The formation of gas bubbles and their function-impairing effect and / or the heating of the fuel are almost completely closed.

The invention is illustrated in the following example with reference to the drawing explained in detail. Show it:

Figs. 1a and 1b schematically illustrates the arrangement of a fuel injection device for a single-cylinder two-stroke engine;

Fig. 2 shows schematically in longitudinal section a first game Ausführungsbei an injection pump according to the invention;

Fig. 3 in cross section an anchor shown in Fig. 2;

Fig. 4 in cross section a valve body shown in Fig. 2;

Fig. 5 shows schematically in longitudinal section a second embodiment example of an injection pump according to the invention.

The fuel injector according to the invention for internal combustion engines is designed as an electromagnetically driven, double-acting reciprocating pump 1 , which works according to the principle of energy storage, so that fuel is injected into the internal combustion engine with short pressure surges.

A first embodiment of the reciprocating piston pump 1 according to the invention is shown in FIGS . 2 to 4.

The reciprocating piston pump 1 has an essentially elongated cylindrical two-part pump housing with a first and second pump housing part 15 , 15 a with a central armature bore 16 , two valve bores 17 , 17 'and two pressure chamber bores 18 , 18 ', each one behind the other in the pump housing 15 , 15 a are introduced and form a passage extending through the entire pump housing 15 , 15 a.

The anchor hole 16 is arranged in the longitudinal axis direction between the Ven tilbohrungen 17 , 17 'and the pressure chamber holes 18 , 18 '. The bores 16 , 17 , 17 ', 18 , 18 ' are arranged concentrically to the longitudinal axis 19 of the pump housing 15 , 15 a, the armature bore 16 and the pressure chamber bore 18 , 18 'each having a larger inner diameter than the valve bores 17 , 17 ', so that the armature bore 16 and the valve bores 17 , 17 'by first ring stages 21 , 21 ' and the valve bores 17 , 17 'and the pressure chamber bores 18 , 18 ' by second ring stage 22 , 22 'are separated from each other.

A direction parallel to the longitudinal axis 19 , which is directed from the second pump housing part 15 a in the direction of the first pump housing part 15 , is defined as the pressure surge direction 27 .

The bores 16 , 17 , 17 ', 18 , 18 ' are arranged approximately mirror-symmetrically to a transverse center plane 12 of the reciprocating pump 1 , the components arranged in the pressure surge direction 27 before (in FIG. 2 to the right of the plane 12 ) the plane 12 a first conveyor pump 13 and the (left of the plane 12 in Fig. 2) of the transverse center plane 12 arranged components form in pressure thrust 27 behind a second feed pump 14.

Same components of the z. B. serving as a pre-feed pump 13 and the z. B. serving as a replenishment pump För derpump 14 are marked with the same reference numerals, the reference numerals of the replenishment pump 14 are provided with a comma (') because the components have substantially the same spatial shapes. 17, 17 ', 18 and 18' as an axial direction information is set as directed away from the transverse center plane 12 "inwardly" than in the direction to the plane 12 and "outward" in the following description in the bores 16.

The armature bore 16 delimits an armature space 23 in the radial direction, in which an approximately cylindrical armature 24 is arranged so that it can move back and forth in the longitudinal axis direction. The armature space is axially in the direction of the feed pump 13 by a first ring stage 21 and in the direction of the feed pump 14 by a first ring stage 21 ', the latter having an end face or face 25 of the second housing part 15 a is formed. The second housing part 15 a is screwed into an axially open end of the core bore 16 of the first housing part 15 with a cylinder-shaped threaded section 26 .

The armature 24 is formed from a substantially cylindrical body with an upstream and rear end face 28 , 29 and an outer surface 30 in the thrust direction 27 with respect to the first feed pump 13 . From the rear end face 28 to approximately the longitudinal center of the armature 24 , the radius increases continuously, so that the armature 24 is conical there and has a conical surface 31 running 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, the inner surface of the armature bore 16 only touches during tilting, as a result of which the friction between the Anchor 24 and the anchor hole 16 is kept low. The provision of the conical area 31 on the armature 24 further reduces the contact and thus the friction surface, as a result of which the possibility of 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 provided in the region of its lateral surface 30 with at least one, preferably two or more grooves 32 running in the longitudinal axis direction.

The armature 24 has two, viewed in cross section, approximately semicircular ( FIG. 3), diametrically opposite segments 24 a arranged between which flat grooves 32 are arranged. A through hole 33 is made centrally in the armature 24 in the longitudinal axis direction.

The bore 33 of the armature 24 is penetrated by a delivery piston tube 35 which forms a central passage space 36 , it projects beyond the armature 24 on both sides.

The delivery piston tube 35 is non-positively connected to the armature 24 . The unit comprising the delivery piston tube 35 and the armature 24 is also referred to below as the delivery piston element 44 . The delivery piston element 44 can also be formed in one piece or in one piece.

The armature 24 and the delivery piston tube 35 have two bores 33 a running perpendicular to the longitudinal axis 19, which produce a connection in the armature 24 between the passage space 36 and the grooves 32 and the armature space 23 .

On the front end face 29 of the armature 24 arranged in the pressure surge direction 27 or in the direction of the pre-feed pump 13 , a first support ring 37 made of plastic sits ben tube 35 through a positive fit. An armature spring 38 is supported on the support ring 37 and extends to a corresponding, corresponding second support ring 39 made of plastic. This ring 39 sits on the first ring stage 21 in the anchor hole 16th

In the valve bores 17 , 17 'sits positively and non-positively in each case a guide tube 40 , 40 ', the guide tube 40 of the pre-feed pump 13 extending rearward into the armature space 23 into the area within the armature spring 38 and the guide tube 40 'of the post-feed pump 14 in the valve bore 17 'ends just before the end face 25 of the rear housing part 15 a and does not protrude into the armature space 23 . At the axially outer ends of the guide tubes 40 , 40 ', a radially outwardly projecting ring web 41 , 41 ' is provided, which is supported on the respective second ring step 22 , 22 'towards the inside. The ring webs 41 , 41 'do not extend radially to the inner surface of the pressure chamber bores 18 , 18 ', so that between the ring webs 41 , 41 'and the pressure chamber bores 18 , 18 ' each have a narrow, cylindrical annular gap 42 , 42 'ver. Through the ring webs 41 , 41 ', the guide tubes 40 , 40 ' are secured against axial displacement inwards.

The non-positively connected to the armature 24 the delivery piston tube 35 extends axially on both sides to the outside until the two guide tubes 40, 40 ', so that the delivery piston tube 35 is guided both at its front end 45 and at its rear end 46th By this two-sided guide at the ends 45 , 46 of the elongated delivery piston tube 35 , the Förderkol benelement 44 is guided tilt-free, so that friction between the armature 24 and the inner surface of the armature bore 16 are largely avoided.

In the axially outer region of the guide tubes 40 , 40 'is in each case a valve body 50 , 50 ' axially displaceable gela gert, each having a substantially cylindrical, elongated, cone-shaped solid body with an outer and inner end face 51 , 51 ', 52 , 52 'and a lateral surface 53 , 53 ' forms. The outer diameter of the valve body 50 , 50 'ent speaks each of the clear width of the passage in the guide tubes 40 , 40 '. On the lateral surfaces 53 , 53 'of the Ventilkör pers 50 , 50 ', an annular web 54 , 54 'is provided, which is arranged approximately at the end of the outer third of the valve body 50 , 50 '. The ring webs 41 , 41 'of the guide tubes 40 , 40 ' form for the ring webs 54 , 54 'of the valve body 50 , 50 ' an abutment, so that they can not be moved further inwards. The valve body 50 , 50 'are provided on their circumference with three longitudinal, flat, wide grooves 55 , 55 ' ( Fig. 4). The ring webs 54 , 54 'are each interrupted in the region of the grooves 55 , 55 '. The number, arrangement or shape of the grooves 55 , 55 'can also be carried out in another way.

The inner end faces 52 , 52 'of the valve body 50 , 50 ' are conical at their edge region and act as a valve seat with the end faces of the ends 45 , 46 of the delivery piston 35 together. The spatial shapes of the ends 45, 46 of the delivery piston tube 35 are adapted as a valve seat on the inner end surfaces 52, 52 'of the valve body 50, 50' by the inner edge of the delivery piston tube is chamfered 35 respectively and the wall of the delivery piston tube 35 inside something is removed. The delivery piston tube 35 thus forms with its ends 45 , 46 each have a valve seat 57 , 57 'for the valve body 50 , 50 '. If the valve body 50, 50 'with their inner faces 52, 52' to the Ventilsit zen 57, 57 ', so is each of the passage through the tube 35 and in the region of the lateral surfaces of the valve body 50, 50' incorporated grooves 55, 55 'blocked.

The from the guide tubes 40 , 40 'forward into the pressure chamber 18 , 18 ' projecting areas of the valve body 50 , 50 'are each surrounded by a pressure chamber body 60 , 60 ', each consisting of a cylinder wall 61 , 61 'and an outer end wall 62 , 62 'exist, wherein in the end walls 62 , 62 ' centrally each have a hole or bore 63 , 63 'is introduced. The pressure chamber body 60 , 60 'are inserted with their cylindrical walls 61 , 61 ' positively and non-positively in the pressure chamber bores 18 , 18 ', being with their at the free ends of the cylinder walls 61 , 61 ' lying face 64 , 64 'to the outwardly projecting ring webs 41 , 41 'of the guide tubes 40 , 40 '. The pressure chamber body 60 , 60 'have on their end faces 64 , 64 ' a vertically duri fende groove 65 , 65 '.

The pressure chamber body 60 , 60 'limit with their interior spaces a pressure chamber 66 , 66 ', into which the valve body 50 , 50 'immerse and can put the fuel in the pressure chambers 66 , 66 ' under pressure. The pressure chambers 66 , 66 'have on their inner region, which extends approximately over half the length of the pressure chamber body 60 and 60 ', a larger clear width than in the outer region. The larger clear width in the inner area is dimensioned so that the valve body 50 , 50 'with their annular webs 54 , 54 ' and a little play in the pressure chambers 66 , 66 'can immerse, whereas the Lich te width of the front area is so dimensioned that only for the ring webs 54 , 54 'extending to the front che che of the valve body 50 and each of these areas surrounding coil spring 67 , 67 ' is sufficient space. As a result, the pressure chambers 66 , 66 'are only slightly larger ausgebil det than the impact movement carried out during the injection process of the valve body 50 , 50 ' claimed space.

The coil springs 67 , 67 'sit with their ends inside on the end walls 62 , 62 ' of the pressure chamber body 60 , 60 'and lie with their other ends on the valve bodies 50 , 50 ' and in particular on the annular webs 54 , 54 ', so that they press the Ven tilkörper 50 , 50 'and the pressure chamber body 60 , 60 ' apart.

The pressure chamber body 60 , 60 'are axially fixed to the outside or in the direction of injection to the front by a connecting piece 70 , 70 ' which are screwed into the outwardly open ends of the pressure chamber bores 18 , 18 '. The connectors 70 , 70 'limit the position of the pressure chamber body 60 , 60 ' axially outward, so that the coil springs 67 , 67 'and the pressure chamber body 60 , 60 ', the valve body 50 , 50 'are tensioned in front. On the outside, the connecting pieces are each formed with a mouth 71 , 71 'for connecting a fuel feed line 72 , 72 ' ( Fig. 1a, 1b). The connecting pieces 70 , 70 'have a bore 73 , 73 ' in the longitudinal axis direction, in each of which a standing pressure valve 74 , 74 'is placed under. The standing pressure valves 74 , 74 'are preferably arranged adjacent to the pressure chamber body 60 , 60 ', so that the pressure chambers 66 , 66 'do not extend further outward and are of small volume.

The fuel delivery lines 72 , 72 'can be connected both to a common injection valve 2 ( Fig. 1a), as well as to an injection valve 2 , 2 ' ( Fig. 1b). The injection valve 2 'for the subsequent delivery is preferably designed so that it atomizes the fuel finer than the injection valve 2 for the advance delivery, so that it injects a cloud of fuel from very finely divided fuel droplets, preferably in the vicinity of the spark plug 10 .

The pressure chamber body 60 , 60 'are provided on their outer surfaces with an annular groove 68 , 68 ', in each of which a plastic sealing ring 69 , 69 ', which seals the pressure chamber body 60 , 60 ' against the inner surfaces of the pressure chamber bores 18 , 18 '.

For the supply of fuel is on the two pump housings 15 , 15 a share a fuel supply opening 76 , 76 'in the region of the pressure chamber bores 18 , 18 ' so that they are in the grooves 65 , 65 'of the pressure chamber body 60 , 60 ' flow out. On the outside in the pump housing parts 15 , 15 'are the fuel supply openings 76 , 76 ' each surrounded by a socket 77 , 77 'for a fuel supply valve 78 , 78 ', which is screwed into the socket 77 , 77 '. The fuel supply valves 78 , 78 'are designed as one-way valves with a valve housing 79 , 79 '. The valve housing 79 , 79 'each have two axially aligned holes 80 , 81 and 80 ', 81 ', the pump housing-side bores 80 , 80 ' have a larger inner diameter than the holes 81 , 81 ', so that between the two bores an annular step is formed, each forming a valve seat 82 , 82 'for balls 83 , 83 '. The balls 83 , 83 'are each biased by a spring 84 , 84 ', which are supported on the housing wall of the housing parts 15 , 15 a in the area of the fuel feed openings 76 , 76 ', against the valve seats 82 , 82 ', so that under pressure fuel supplied from outside the balls 83 , 83 'from the valve seats 82 , 82 ' can lift and fuel through the bores 80 , 80 ', the fuel feed openings 76 , 76 ' and the grooves 65 , 65 'in the Druckkammerbohrun conditions 18 , 18 'or in the pressure chambers 66 , 66 '.

From the pressure chambers 66 , 66 'extends through the grooves 55 , 55 ' of the valve body 50 , 50 ', between the valve seats 57 , 57 ' of the delivery piston tube 35 and the inner end faces 52 , 52 'of the valve body 50 , 50 ', if these are arranged at a distance, through the passage space 36 of the delivery piston tube 35 and the bores 33 a in the piston element 44, a passage into the armature space 23 .

At the peripheral area of which is arranged on the side of the pre-feed pump 13 first annular step 21, an outwardly leading bore 90 as a fuel outflow opening is introduced. The bore 90 is extended on the outside by a connecting piece 91 for connecting a fuel return line 92 ( FIG. 1).

The second pump housing part 15 a has a circumferential radially outwardly projecting ring step 93 adjacent to the cylin-shaped threaded section 26 . The annular step 93 also serves, among other things, for the axial fixation of a coil housing cylinder 95 which surrounds the first pump housing seteil 15 on the outside. The coil housing cylinder 95 consists of a first, wide cylinder wall 96 Zy and a second, narrow cylinder wall 97 with a smaller inner diameter than the first cylinder wall 96 , the web 98 are integrally connected to one another via a radially extending ring web. The coil housing cylinder 95 is pushed with its first cylinder wall 96 pointing forward onto the first housing part 15 until the first cylinder wall 96 abuts a housing wall 100 projecting outward from the first pump housing part 15 and thus an annular chamber 101 with an approximately rectangular cross section for receiving a coil 102 limited.

The coil housing cylinder 95 is thus between the housing 100 and the ring step 93 of the second housing part 15 'a clamped and fixed in its axial position. The second cylinder wall 97 of the bobbin case cylinder 95 is chamfered on the inner edge of its end face pointing to the refill pump 14 , with a sealing ring 103 , such as, for example, between the bevel formed therein, the first housing part 15 and the ring step 93 . B. an O-ring is clamped.

Coil 102 is molded in cross-section approximately rectangular in shape and in a U-shaped-cross-section support body 104 by means of epoxy resin cylinder, so that the coil 102 and the support body form a one-piece cylinder 104 coil module. The supporting body cylinder 104 has a cylinder 105 and two Seitenwandun gen 106, 107 that project radially and outwardly from the cylinder 105 to limit the space for the coil 102, wherein the cylinder wall 105 extends laterally over the rear side wall 106 out so that whose end face 108 , the end faces 109 of the side walls 106 , 107 and the inner surfaces of the cylinder wall 106 and the front side wall 107 form fit in the annular chamber 101 .

In the area of the first pump housing part 15 , which is arranged between the coil 102 and the armature space 23 , a mate rial with low magnetic conductivity 110 , z. B. copper, aluminum, stainless steel, to avoid a magnetic short circuit between the coil 102 and the armature 24 is introduced.

A second embodiment of the injection pump according to the invention is shown in Fig. 5.

The reciprocating pump 1 according to the second embodiment has essentially the same structure as the reciprocating pump 1 described above, so that parts with the same spatial shape and the same function are identified by the same reference numerals.

The reciprocating pump according to the second embodiment is shorter in its longitudinal extent than the reciprocating pump according to the first embodiment, the shortening being achieved essentially by the use of balls 50 a, 50 a 'as a valve body. The ring webs 41 , 41 'of the guide tubes 40 , 40 ' form for the balls 50 a, 50 a 'an abutment, so that they can not be moved further inward, the ring webs 41 , 41 ' each with one attached to the spherical shape Fitted annular ball seat 41 a, 41 a 'are formed so that the balls 50 a, 50 a' partially form-fitting to the rings webs 41 , 41 '.

The balls 50 a, 50 a 'have a smooth surface, which is why in the ball seats 41 a, 41 a' grooves 41 b, 41 b 'are introduced, which sit the pressure chambers 66 , 66 ' with the gap between the valve 57 , 57 'of the delivery piston tube 35 and the surfaces of the balls 50 a, 50 a' connect if these are arranged at a distance from the Ven valve seats 57 , 57 '. By providing the grooves 41 b, 41 b ', the flushing through the delivery piston tube 35 is made possible.

The mode of operation of the A according to the invention is described below Spray device based on the first embodiment of the Invention explained.

If the current flow through the coil 102 is interrupted, the armature 24 is pressed backward by the armature spring 38 against the end face or stop face 25 of the second housing part 15 a, against which the armature 34 rests with its rear end face 49 . This is the starting position of the armature 24 , in which the delivery piston tube 35, with its valve seat 57 pointing in the direction of the pre-delivery pump 13 , is arranged at a distance s _V from the rear end face 52 of the valve body 50 . In this starting position the delivery piston tube 35 acted upon by the valve seat 57 'the valve body 50' of the Nachförderpumpe 14 against the spring action of the coil spring 67 ', so that the annular rib 54' of the valve body 50 'at a distance s _R from the annular web 41' of the guide tube 40 ' is spaced.

In this starting position, a fuel under 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 of the pre-feed pump 13 . From 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 inner end face 52 of the valve body 50 and into the passage space 36 of the delivery piston 35 . From the passage space 36 of the delivery piston 35 , the fuel under pressure flows through the bores 33 a through the delivery piston tube 35 and the armature 24 and floods the armature space 23 . The areas of the armature space 23 in front of and behind the armature 24 are communicatively connected to one another by the grooves 32 made in the armature 24 , so that the entire armature space 23 is filled with fuel. Through the bore 90 and the connecting piece 91 , the fuel is passed back into the fuel tank 111 .

Thus, in the starting position of the delivery piston element 44 there is a fuel supply valve 78 via the pressure chamber 66 of the pre-feed pump 13 , the passage space 36 of the delivery piston 35 , the bores 33 a in the piston element 44 , the armature chamber 23 , the bore 90 and the connecting piece 91 extending flow path for the fuel, so that fuel is continuously supplied and flushed through the flow path, the pressure chamber 66 of the pre-feed pump 13 always being supplied and flooded with fresh, cool and therefore bubble-free fuel directly from the fuel tank 111 .

The upstream pressure generated by the fuel pump 112 is on the one hand greater than the pressure drop arising in the flow path, so that a continuous flushing of the reciprocating piston pump 1 is guaranteed, and on the other hand is smaller than the passage pressure of the auxiliary pressure valve 74 , so that in the initial position of the delivery piston element 44 none Fuel is delivered from the reciprocating pump 1 to the injection nozzle 2 .

If the coil 102 is excited by the application of an electric current, the armature 24 is moved in the direction of the pre-feed pump 13 by the magnetic field generated in this way and executes a movement which actuates the valve body 50 of the pre-feed pump 13 for a pre-injection. The movement of the piston element 44 (= armature 24 and delivery piston tube 35 ) acts during a Vorhu bes over the length s _V (corresponds to the distance between the Ven valve seat 57 of the delivery piston tube 35 and the inner end face 52 of the valve body 50 in the starting position) only the spring force against the armature spring 38 . The spring force of the armature spring 38 is so soft that the armature 24 is moved almost without resistance, but the spring force is still sufficient to return the armature 24 to its initial position. The armature 24 "floats" in the pressure chamber 23 filled with fuel, the fuel being able to flow back and forth between the regions in front of and behind the armature 24 in the armature chamber 23 , so that no pressure opposing the armature 24 is built up. The delivery piston element 44 , which consists of the armature 24 and the delivery piston tube 35 is thus accelerated continuously and stores kinetic energy.

During the impact movement of the piston element 44 in the direction of the pre-feed pump 13 , the valve body 50 'of the post-pump 14 is moved due to the spring action of the coil spring 67 ' with the piston element 44 until its ring web 54 'abuts the ring web 41 ' of the guide tube 40 '. Here, the volume of the pressure chamber 66 'of the replenishment pump 14 is increased so that "fresh" or bubble-free fuel is drawn in via the fuel supply valve 78 '. After the reciprocating member 44 one forward stroke over the distance s _R (corresponding to the distance between the annular rib 59 'of the valve body 50' of the annular web 41 'of the guide tube 40' in the initial position of Hubkolbenelements 44) has carried out, the valve seat 57 solves' from the inner end face 52 'of the valve body 50 ', so that between the end face 52 'and the valve seat 57 ' forms a distance which forms a passage from the pressure chamber 66 ', through the grooves 55 ' in the passage space 36 of the delivery piston tube 35 . Thus, a continuous flow path from the fuel supply valve 78 'to the armature space 23 and the bore 90 forms during the impact movement of the piston element 44 .

At the end of the forward stroke s _V , the delivery piston element 44 strikes with the valve seat 57 on the inner end face 52 of the valve body 50 of the pre-delivery pump 13 , so that it is suddenly pressed outwards. Since the delivery piston tube 35 is now with its valve seat 57 on the inner end face 52 of the valve body 50 , the flow path from the pressure chamber 66 of the Vorför derpump 13 to the passage space 36 of the delivery piston tube 35 is interrupted, so that the fuel from the pressure chamber 66 is no longer can escape to the rear. The fuel is thus displaced from the pressure chamber 66 by the impact and the further feed movement of the Ventilkör pers 50 , wherein he is under pressure. The fuel supply valve 78 is closed here because a pressure builds up in the pressure chamber and in the bore 80 of the fuel supply valve 78, which pressure is greater than the pressure at which the fuel is supplied by the fuel pump. From a predetermined pressure, the stand pressure valve 74 opens so that a predetermined pressure is exerted on the fuel in the delivery line between the injection nozzle 2 and the reciprocating pump 1, which is, for example, 60 bar and fixed by the passage pressure of the injection nozzle 2 is. With the impact of the delivery piston element 44, the Stored-assured energy in the movement of the delivery piston element 44 is thus instantaneously transmitted to the befind union in the pressure chamber 66 fuel.

The length of time during which the solenoid 102 is energized and the piston element 44 is moved determines the path traveled by the valve body 50 when fuel is displaced in the pressure chamber 66 , as a result of which the fuel delivered by the pre-feed pump 13 is proportional to the distance traveled by the valve body 50 or proportional to the time interval during which solenoid 102 is energized. The maximum conveying path can be a multiple of the distance s _V between the valve seat 57 and the inner end face 52 of the valve body 50 in the starting position of the piston element 44 .

The fuel delivery of the pre-feed pump 13 is terminated by switching off the current of the solenoid 102 , whereupon the reciprocating element 44 is moved back into its starting position by the spring action of the armature spring 38 and carries out a recoil movement in order to actuate the valve body 50 'of the post-delivery pump 14 for a post-injection. The armature 24 is at a distance sR from the stop surface 25 , so the Hubkol benelement 44 strikes with its valve seat 57 pointing towards the refill pump 14 'on the valve body 50 ' and pushes it into the pressure chamber 66 ', with fuel from the pressure chamber 66 'is displaced. The armature 24 strikes the stop surface 25 , as a result of which the stroke s _{R of} the feed pump 14 is abruptly interrupted and the piston element 44 is again in its starting position.

The recoil movement of the piston element 44 can also be delayed by the fact that after the completion of fuel delivery with the pre-feed pump 13, the solenoid is not de-energized, but the current value for a predetermined delay time interval is reduced to a level that the piston element 44 no longer in the direction of impact 27 moves and inhibits its return movement, so that the piston element 44 strikes with a time delay on the valve body 50 '. As a result, the time interval between the fuel delivery of the pre-feed pump 13 and the fuel feed of the post-delivery pump 14 can be controlled.

The distance traveled by the valve body 50 's _R during the injection process of the replenishment pump 14 is the same length for each replenishment so that the replenishment pump 14 always injects the same amount of fuel per injection process. This constant injection quantity is preferably selected so that it corresponds to the fuel consumption of the engine connected to it in idle mode.

The stroke s _{V of} the prefeed pump 13 is preferably greater than or equal to the stroke s _{R of} the refill pump (s _V s _R ), so that the full continuous stroke of the refill pump 14 can be carried out without fuel being supplied to the prefeed pump 13 .

With the double-acting reciprocating piston pump 1 according to the invention, a variable amount of fuel can be injected in a metered quantity with the pre-feed pump 13 , the injection being able to take place at a clear time before the ignition process, so that there is a sufficiently long period of time for a swirling of the fuel amount. This results in an ideal distribution of the fuel in the combustion chamber.

A second constant amount of fuel is just before or equal to injected at the time of ignition, which is already in the burner Enriched space fuel brought in areas, so that an inhomogeneous mixture distribution in the combustion chamber with the enriched area preferably nearby the spark plug is arranged so that the mixture ignites easily bar and a flame front spreads very evenly. In this way, ideal combustion conditions are achieved, so that the pollutant concentration in the exhaust gas and the fuel ver reduce significantly. In addition, due to the ideal Distribution of the fuel / air mixture in the combustion chamber of the engine operated with mixtures of different quality or octane number be.

Claims (18)

1. Fuel injection device, which works on the solid-state energy storage principle, and is designed as a reciprocating pump with a delivery piston element ( 44 ) which is moved from its starting position towards a pressure chamber ( 66 ), during an almost resistance-free acceleration phase stores kinetic energy, which is suddenly transmitted by a shock movement to fuel in the pressure chamber ( 66 ), so that a pressure surge for spraying fuel is generated by an injection nozzle device, characterized in that a second pressure chamber ( 66 ') on that of the first Pressure chamber ( 66 ) opposite side of the Förderkolbenele element ( 44 ) is arranged such that the kinetic energy absorbed in the return movement of the delivery piston element ( 44 ) in its initial position is transferred to a fuel located in the two th pressure chamber ( 66 ') . 2. Fuel injection device according to claim 1, characterized in that the kinetic energy is stored during the return movement into the starting position during an almost resistance-free acceleration phase, and that the stored kinetic energy by a recoil movement abruptly on the in the second pressure chamber ( 66 ' ) be sensitive fuel is transmitted. 3. Fuel injection device according to claim 1 or 2, characterized in that the interruption of the resistance-free acceleration phase and the pressure surge in the first pressure chamber ( 66 ) generating means is a valve having a valve body ( 50 ) and one on the delivery piston element ( 44 ) formed valve seat ( 57 ) and closes the first pressure chamber ( 66 ) to generate the pressure surge, the valve seat ( 57 ) and the valve body ( 50 ) being arranged at the front end ( 45 ) of the delivery piston element ( 44 ), so that the pressure chamber ( 66 ) is spatially separated from the delivery piston element ( 44 ). 4. Fuel injection device according to claim 2 or claim 2 and claim 3, characterized in that the resistance-free acceleration phase interrupting and the pressure surge in the second pressure chamber ( 66 ') generating means is a valve having a valve body ( 50 ') and a formed on the delivery piston element Ven tilsitz 'includes and for producing the pressure surge, the second pressure chamber (66 (57)', closes) the valve seat (57 ') and the valve body (50') at the front in the direction of recoil end (46) the delivery piston element ( 44 ) are arranged so that the pressure chamber ( 66 ') is spatially separate from the delivery piston element ( 44 ). 5. Fuel injection device according to one or more of claims 1 to 4, characterized in that the fuel injection device as an electromagnetic table-operated reciprocating pump ( 1 ) with a solenoid coil ( 102 ) and the driven by the coil ( 102 ) benelement Förderkol ( 44th ) is formed, the delivery piston element ( 44 ) having an approximately cylindrical armature ( 24 ) and an elongated delivery piston tube ( 35 ), the ends ( 45 , 46 ) of the delivery piston tube ( 35 ) extending in the longitudinal direction over the armature ( 24 ) extend and are each positively and slidably mounted in the longitudinal axis in recesses. 6. Fuel injection device according to claim 5, characterized in that the delivery piston tube (35) is frictionally connected to the armature (24), at the ends (45, 46) of the conveyor piston tube (35) each one of the valve seats (57, 57 ') is arranged. 7. Fuel injection device according to claim 3 and 4 or claim 3 and 4 and claim 5 and / or 6, characterized in that the or the valve body ( 50 or 50 ') each form an elongated substantially cylindrical solid body in one Guide tube ( 40 , 40 ') is axially slidably mounted, wherein it is provided on its circumference with longitudinally extending grooves ( 55 and 55 ') which provide a passage from one of the pressure chambers ( 66 and 66 ') into a passage space ( 36 ) form within the För derkolbenrohres ( 35 ), the passage being blocked when one of the valve seats ( 57 , 57 ') on the respective valve body ( 50 or 50 '), whereby the corre sponding pressure chamber ( 66 and 66 ') closed is. 8. Fuel injection device according to claim 3 and 4 or claim 3 and 4 and / or 6, characterized in that the valve body or bodies are a ball ( 50 a, 50 a '), with ball seats ( 41 a, 41 a') are provided, which form an abutment for the balls ( 50 a, 50 a ') so that they cannot be moved further inwards, and the ball seats ( 41 a, 41 a') each have at least one groove ( 41 b, 41 b ') which form a passage from one of the pressure chambers ( 66 or 66 ') into a passage space ( 36 ) within the delivery piston tube ( 35 ), the passage being blocked when one of the valve seats ( 57 , 57 ' ) on the respective valve body ( 50 or 50 '), whereby the corresponding pressure chamber ( 66 or 66 ') is closed. 9. Fuel injection device according to one or more of claims 5 to 8, characterized in that the approximately cylindrical armature ( 24 ) has a front and rear end face ( 28 , 29 ) and a lateral surface ( 30 ) in the direction of impact, and one of the rear end face ( 28 ) up to about the longitudinal center of the armature ( 24 ) from the back to the front outside conical surface ( 31 ). 10. Fuel injection device according to one or more of claims 5 to 9, characterized in that the reciprocating pump ( 1 ) has a pump housing with an armature bore ( 16 ) in which an armature space ( 23 ) through the armature bore ( 16 ) in the direction of impact is forwardly defined by a first annular step (21) and in thrust rearwardly by a second annular step (22), in which the armature (24) by a solenoid (102) and one in Längsachs direction the armature (24) acting on the armature spring (38 ) is moved back and forth, the armature ( 24 ) being formed on its jacket region with a groove ( 32 ) running in the longitudinal direction. 11. Fuel injection device according to claim 10, characterized in that the armature ( 24 ) assumes its starting position by the spring action of the armature spring ( 38 ) when the coil ( 102 ) is switched off, the direction of the first valve chamber ( 66 ) directed valve seat ( 57 ) at a distance (s _V ) to a corresponding end wall ( 52 ) is angeord net, and the valve seat ( 57 ') arranged in the direction of the second pressure chamber ( 66 ') on the corresponding end face ( 52 ') of the corresponding Valve body ( 50 ') abuts so that it is pressed somewhat into the pressure chamber ( 66 '). 12. Fuel injection device according to claim 11, characterized in that the piston element ( 44 ) has a bore ( 33 a) which connects the passage space ( 36 ) within the delivery piston tube res ( 35 ) with the armature space ( 23 ), and that Armature chamber ( 23 ) is connected to a fuel return line ( 92 ) via a bore ( 90 ) leading to the outside and a connecting piece ( 91 ). 13. Fuel injection device according to one or more of claims 1 to 12, characterized in that the pressure chambers ( 66 , 66 ') are each limited by a stand pressure valve ( 74 , 74 ') which opens from a predetermined pressure and the Passage in a fuel delivery line ( 72 ) to an injection nozzle ( 2 ) clears. 14. Fuel injection device according to one or more of claims 1 to 13, characterized in that the first and / or second pressure chamber ( 66 or 66 ') is only slightly larger than the impact movement of the respective valve body (during the injection process) 50 , 50 ′) occupied space. 15. Use of a fuel injector after one of claims 1 to 14, according to the solid-state energy principle works and a delivery piston element points, which is reciprocated in the reciprocating piston pump, while during an almost resistance-free acceleration phase stores kinetic energy that suddenly by an impact movement in a pressure chamber Chen fuel is transferred so that a pressure surge to Spraying fuel through an injector device  device is generated, and a second pressure chamber on the first pressure chamber opposite side of the delivery piston benelements is arranged so that the back movement of the reciprocating piston element recorded kinetic Energy on force in the second pressure chamber material is transferred by a recoil movement, so that a second pressure surge to spray fuel through an injector device is generated, wherein by the first push movement from the first pressure chamber a first amount of fuel is delivered, the force Amount of substance depending on the through the piston elements distance covered during the impact movement is controlled, and that a second amount of fuel with time Lich distance to the first amount of fuel from the second Pressure chamber through the recoil movement of the reciprocating piston funded. 16. Use according to claim 15, characterized, that the fuel delivered from the second pressure chamber amount is constant, and that this amount of fuel at Injecting into a combustion chamber of an engine is ignited. 17. Use according to claim 15 or 16, characterized, that the second amount of fuel is about the idle demand operation corresponds and the first amount of fuel to one Time is injected, the crankshaft position 60 ° or more before TDC. 18. Use according to one or more of claims 15 to 17, characterized in that the piston element by means of a solenoid is operated and that the first force Amount of substance over the period of time to excite the coil applied current pulse is controlled.