DE2009366A1 - Fuel injection device for a diesel engine - Google Patents

Description

Mitsubishi Jukogyo Kabushiki Kaisha 27, Teh. ; ij? (J Tokyo 'Japan -'

Fuel injection device for a diesel engine

The invention relates to a fuel injection device for a diesel engine.

In a known diesel engine, the fuel injection process usually begins several degrees before top dead center, ie at -10 ° to -3 ⁹ , during the earning cycle, both when starting and during operation.

If the starting ambient temperature is low, can the air in a cylinder chamber or a combustion chamber because of the low temperature of the whole machine as well as the intake air do not reach a sufficiently high temperature, although the air is compressed. As a result, the ignition delay is prolonged and is during the injection period, by some Degrees before top dead center in the compression stroke shortened the period of time during which the fuel droplets come into contact with the high temperature air in the compression room. The ignition of the As a result, fuel droplets become very difficult.

In another already proposed diesel engine nen design is several degrees before the top dead center in the compression stroke before the actual fuel injection made an additional fuel injection at the beginning of the compression stroke. With this diesel engine— Design, the total amount of fuel injected is practically constant both during start-up and during operation. This diesel engine should be efficient

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improved by improving the Verreinungsbedingungen of the fuel and also the control ozw. Control of the way of working are facilitated.

Although this type of diesel engine because of the two-stage additional fuel injection excellent an-IaI j properties, it still has an i. Since the second stage of the additional fuel injection takes place at the first stage fol-t and that at the first :: stage the amount of fuel injected by a the cam lift of a piston is determined, it is impossible to on zv / square quiet the time of the Legiun adjust the fuel injection in the second stage without the fuel injected in the first Sruf To change the amount of fuel and without bulging the one

Acting liegel-I.'ocicen by a curl of different Replace contour.

In contrast, the invention relates to an improved one Injection device for diesel engines to significantly improve starting behavior Low temperature conditions.

More precisely, the invention relates to an improvement of the diesel engine egg injection device of the aforementioned type, which operates with an additional fuel injection when starting. he ± this injection device comprises a cylinder or a Kolbenbonrung a fuel inlet and an axially displaceably guided in the bore piston or slide. A squat used to actuate the piston has elevations spaced from one another in the circumferential direction in such a way that the piston, after it has been advanced into a first position during the intake or compression stroke and returned again, is advanced further into a second position at the end of the compression stroke . A switching device can move the piston over practically 180

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between an "occasion" and a "running" position twist.

In the starting position, the fuel inlet is through blocked the circumferential surface of the piston so that during the movement of the piston in the first and in the second Position; ζ v / ei fuel injections carried out The piston is in the operating or running position rotated into a position in which the inlet is blocked by its circumferential surface, so that only when When the piston is moved into the second position, fuel is injected

According to the invention, a passage is provided in the piston, the the circumferential surface of the piston with its in the bore or * the inner face located in the cylinder connects. Communicates in the starting position of the piston this passage with the fuel inlet when the piston has been advanced to said second position. When the diesel engine is in operation, the piston is in twisted a position in which the passage is not more with the inlet, can communicate.

The arrangement according to the invention has the advantage that even if the ambient temperature is too low; .is to the iiii suction air to reach a sufficiently high temperature by setting the switching device in the Starting position of the fuel over a longer period of time evenly mixed away with the intake air and then in the first "stage of the additional fuel injection is heated, whereby the ignition delay is shortened to such an extent that an ignition takes place with certainty. The necessary to spin the diesel engine ■ torque "can, in d-.r second stage of the additional Fuel injection will be generated · Subsequently will when the diesel engine is running, while its temperature increases, the 'fuel injection only when the engine is running'

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Shifting the piston into the second position carried out by the control or switching device in the 'running position is switched. The diesel engine then runs smoothly, while the fuel is exactly what is required for normal operation Amount is injected. In addition, the amount of fuel injected are considerably reduced in normal operation compared to the amount of fuel used when starting, whereby a reduction of the thermal efficiency is avoided

More precisely, the interior of the cylinder or · P of the bore in the starting position of the piston is in the Period of time between the first and the second position of the piston connected to the fuel inlet. Consequently can be both the start time of the injection and the injected fuel quantity in the second Injection stage can be set at your discretion by the time at which the inlet through the piston circumferential surface is blocked, is delayed accordingly, without changing the contour of the Hegel cam for this purpose needed to be.

The object of the invention is therefore primarily to create an improved fuel injection device for diesel engines.

The invention also encompasses the creation of such Injection device for diesel engines, by means of which the starting behavior of the diesel engine is significantly improved will.

Furthermore, according to the invention, the creation of an improved injection device of the type mentioned is to be achieved, loi vrelciiT the amount of fuel injected in iiormalbetrieb -: '. E ^ · DiVw ^ liBischine gogpn over the .starting aer iiiosolmaEcliine- e ing esprit at en Fuel-

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amount can be reduced considerably, so that a Reduction of the thermal efficiency is prevented.

Finally, another object of the invention relates to the creation of an injection device of the type mentioned, in which the starting time of the fuel injection and the amount of fuel injected in the second additional injection step without changing the contour of one actuating the injection piston Cone cam and can be set at your choice without replacing this cam.

The invention is explained in more detail below in typical exemplary embodiments with reference to drawings. It demonstrate:

Pig. 1 is a schematic longitudinal section through a conventional fuel injector for a diesel engine,

Fig. 2 is a view of another according to the system Fig. 1 similar embodiment of an already proposed fuel injection device,

3 shows a partial side view in the direction of the arrows

III-III seen in Fig. 2, \ I

4 shows a longitudinal section, on an enlarged scale, of a main part of the device according to FIG.

5 shows a schematic representation of the fuel injection device according to Fig. 2,

Figure 6 'is a graph showing the relationship between the cam stroke and the piston when starting or in normal operation of the device according to FIG. 2,

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I) ¹ Ig. 7 shows a graphic representation of the working principle of the injection device according to FIG. 2,

8 shows a schematic illustration of an embodiment of a fuel injection device with the features of the invention for use in a diesel engine,

9 shows a graphical representation of the relationship between ho cken stroke and piston when starting or in normal operation of the device according to FIGS

Fig. 10 is a schematic section to illustrate the main part of a modified embodiment the invention.

In a conventional pre-chamber diesel engine shown in FIG. 1, the air compressed on the upstroke of a piston a in a main space b flows through a passage c into a pre-chamber d, the air at a low temperature due to the throttling loss at passage c in FIG Pre-chamber d is cooled. For this reason, even at the end of the compression stroke, it is difficult to let the air in the prechamber d reach the ignition temperature. When starting, the fuel injected into the prechamber d by a fuel injection pump e via a nozzle f must therefore reach the main space b, roughly flowing through the prechamber d and the passage c. However, since the flow velocity of the air from the main room b via the passage c is quite high _{3 it} is almost impossible for the injected fuel jet to get into the main room b bad * starting behavior »

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To improve the starting behavior is already one Fuel injection device shown in Figs for diesel engines has been proposed (German patent application Akt.-Z. P 19 57 370.7). at of this device, a piston 2 is in a main space or cylinder 1 can be moved back and forth in a straight line, the main room 1 via a passage 3 communicates with an antechamber 4. At the antechamber 4 is a nozzle provided with a nozzle needle valve 5 6 is provided while a fuel injection pump housing 8 is connected to the nozzle 6 via a line 7 is.. .

In the injection pump housing 8 is an axially linearly displaceable slide or piston 12 with a stepped Section 11 out, which is arranged under a supply valve housing 10, which is a supply valve 9 records. The slide or piston 12 can be moved axially to the housing 8 by means of a Hegel cam 13, which is synchronized with the rotary motion of the diesel engine nen crankshaft is set in rotation.

A rack 14 meshes with teeth, not shown on the circumference of the piston or «slide 12 and is with the one end 15b of a fork lever 15 connected, which is approximately is pivotably mounted in its central part 15a. The other end 15c of the fork lever 15 is in contact with a displaceable shaft 16a of a regulator 16. From Middle part 15 a of the fork lever 15 is an arm 15 d, which is connected to a Hegelknopf.18 via a spring 17 is. In addition, the injection pump housing is to be stranded with a starter button 19 on the pump cylinder 8a A fuel inlet 22 is provided within the housing 8.

When the control button 18 Geraäß Fig. 5 preset in a starting position and

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the start button shown in phantom in Fig. 4 19 in the drawn out position in Pig · 4 is spent, a protruding from the rack 14 pin 20 is free from a stop 21 so that the rack can move from the normal operating position to the starting position. Here, the slide or piston 12 is rotated into a position in which the top 11a of the stepped section «baw. the inner end face 11 of the slide or piston 12 opposite the inlet 22

If, under these conditions, the simmering machine is turned over with the aid of a known starter (not shown), the lever cam 13 is rotated counterclockwise according to FIGS. 2 and 3 a stroke position I Lf shown in the left half of the upper section of FIG. 6 into another stroke position _{I 7} shown in the right half of the upper section of FIG. 6. During this period of time, the fuel inlet 22 is blocked by the upper part or projection 11a of the inner end face 11 of the slide or piston 12. As a result, a first fuel injection is carried out in which approximately half of the total amount of fuel to be injected is injected. The timing for the lifting of the slide or piston by the first cam lobe 15a is set to the end of the intake stroke or to the start of the compression stroke. For this reason, the fuel injected into the prechamber 4 during the first injection stage flows through the passage 3 into the main chamber 1. During the compression stroke, this fuel is sufficiently mixed with the intake air and heated to a high temperature.

When the first Iiocken protrusion 13a at the lower end of the

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Slider eg “piston 12 has passed”, the latter shifts so far downwards that the force st of f-injection is interrupted. A second cam elevation 1J5h then comes into contact with the lower end of the slide baw * piston 12 and lifts the latter, a further fuel injection stage being initiated when the slide baw * piston 12 has reached the stroke position I *. Inawischen increases the temperature tra (]? I§v 7) of the gas mixture of fuel and kufts in the main room 1 over the temperature tp in the pre-chamber 4. The gas in the main room 1 can therefore be ignited more easily than that in the pre-chamber 4- The fuel injected during the second stage continues to flow at the moment in which the flow velocity CU through the passage 3 is reduced, at least partially into the main space 1, the fuel flowing through the Durehiang J burns with the gas mixture and thus the explosive force required for starting provides _% so that the diesel engine can be started very easily

As soon as the liieselmasohina has reached a predetermined range, the centrifugal force of a weight 1tb mounted on the regulator 16 moves the displaceable one. Wave 16ades leglers in the light of the arrow according to Big ». % As a result, the Lahn rod shifted 14 through the fork lever 15 and the slider BAW · piston 12 via an angular stepped from 180 ° twisted so that the lower part 11b of the grooved baν? · Stepped innerea end face of the slider bfcvf * piston 12 relative to the fuel -Inlet 22 siu comes lying *

if 4p slide baw · piston 12 under these conditions DE® 13a linfluß the first cam survey in four © P Hubstelluni% arrives _t can not Einspritaung dureh ^ eführt who eji & |. Since the port 22 has not been blocked, let «lur d &» & _% when the slide baw »piston. 12th

under the .Influence of the second cam elevation 13b in the lift position I ₂ , the fuel inlet 22 is blocked by the lower part 11b of the stepped inner end face 11 of the piston or slide 12 so that the fuel can be injected. In order to maintain normal operation of the diesel engine, a smaller amount of fuel is injected than when starting, similar to a conventional diesel engine.

Even if the diesel engine has not reached the predetermined speed when the Hegel button 18 is in the ^ Normal operating position has been set, the The piston or slide 12 is rotated and adjusted so that the lower part 11b of the inner end face 11 opposite the inlet 22 is located.

In the already proposed fuel injection device according to FIGS. 2 to 7 can be changed by changing the height of the stepped section of the inner end face 11 of the piston or slide 12 or the stroke height 1. and I ^ of the cam lobes or both factors, the amount of fuel injected in the first stage during starting can be set to 25-75% of the total amount of fuel injected W , while the total amount of fuel injected during starting can also be set to 150-3QQ # the amount of fuel injected for maximum performance in normal operation can be set.

As mentioned, does the already proposed injection system according to FIGS. 2 to? when starting better machine behavior or better performance than a direct injection machine. This is to be traced back to the fact that when starting at the beginning of the Compression stroke when the speed of the airflow is low in passage 3, a first injection stage

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is carried out so that the fuel get into the building space 1 in sufficient quantity and the Ignition in the main room i at a higher temperature than that the compressed air take place in the antechamber-4 can·

However, Ba is the second stage of fuel injection begins at the moment in which the slide or · Piston 12 moved upwards again and in the crouching lift position 1, arrives ^ after it is initially in the stroke division 1 * lifted and moved back again is, and since the amount of fuel injected in the

first stage determined by the stroke positions 1- and I ^ becomes, it is impossible to expediently determine the starting point the fuel injection during the second injection stage without changing the injection quantity to vary in the first stage and without the Hegel-Squat 13 by another with different Replace contour »

According to the Pig. 8 and 9 is a fuel injector of the type shown in Figures 2 to 7 modified according to the invention in such a way that a connection path or * passage from the lower part 11b of the inner end face of the slide or piston 12 is provided, which moves downwards and then laterally to the circumferential surface of the Slide or piston 12 extends and in the An3tiBstatus the parts facing the inlet 22. The opening 23a this passage lies on the slide peripheral surface at such an altitude that it is opposite the fuel inlet 22 in the lift position 1- of the Hegel cam.

As a result of this design of the embodiment according to FIGS. 8 and 9, when the slide or piston 12 is adjusted during starting in such a way that the upper part 11a of its stepped inner end face 11 is opposite the inlet 22 , as in the upper half of FIG

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9, in the position in which the lift position 1 is determined by the first cam elevation 13a, the upper space in the slide cylinder 8a is connected to the inlet 22 via the passage 23. Even if the slide or piston 12 is raised slightly by the second cam elevation 13b from the lift position 1-, the second stage of fuel injection is only initiated when the one located on the circumferential surface of the slide or piston 12 Opening 23a has been shifted from inlet 22 in the upward direction to the cam lift position 1 ^. In the stroke position I ₁ . the connection between the upper space in the cylinder 8a and the fuel inlet 22 is interrupted, so that the second fuel injection stage is initiated.

As shown in the lower half of FIG. 9, however, the starting point in time of the fuel injection differ as well as the injection quantity in normal operation in the position of the part in which the slide or piston 12 is rotated by 180 ° to switch to normal operation, while the opening 23a of the passage 23 is turned away from the fuel inlet 22, not from the start time and the injection quantity, which is when omitted; of the lower .D Durchgangs 23 would result, so that both factors are kept constant.

At d, r in the fi £. 8 and 9 illustrated embodiment of the ^ rfindun ^; The start time of the fuel injection and the amount of fuel injected during the time of the start-up injection can be changed in a very simple and practical way by j - .. change _: -_; the diameter or the height oaer both waters on the circumferential surface of the slide or /. Piston 12 Ci'fnun lying _f ^r:; 23a set v; eide .. without changing the form of the 1, 'ockon-Erhebunf.en 13a and 13b. This creates a Kx'ai't after starting

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fuel injection ensures that it is optimally suited to the various characteristics of the diesel engine, such as starting behavior, output power, noise generation USW *, is tuned so that the performance of the Diesel engine is improved.

In the embodiment according to FIGS. 8 and 9, a stepped or notched section 11 is provided. Leave the same way of working and the same advantages however, can also be achieved when the upper or inner end face of the slide or piston 12 according to FIG Prop. 10 cut at an angle and the passage 23 formed is that the opening 2Yes to the higher. " End of the inclined face of the slide or piston 12 comes to rest.

Instead of end faces of the slide or piston 12 located at different heights, change; provide respective sides, the upper side thereof can optionally also are perpendicular to its longitudinal axis, while on the slide cylinder 8a-inlets -fuel be provided 22 in comparable ^τ different altitudes more and is disposed around the outer periphery of the cylinder 8a is a sleeve that both is freely displaceable axially and circumferentially. By optionally shifting an opening formed in the sleeve * ^ into a position opposite one of the various inlets 22, a two-stage. Achieve injection when starting and single-stage injection in normal operation. Although only a single passage 23 is provided in the illustrated embodiments, two or more passages can also be provided if desired.

In summary, the invention thus creates a fuel injection device for a diesel engine, which a valve cylinder with a fuel inlet and a slide axially displaceable in this cylinder

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or piston. One of the slide or piston active regular crouching has two elevations for actuating the slide or piston. During the The intake or compression stroke, the control cam moves the slide or piston into a first position, in which he blocks the inlet for injecting fuel, whereupon the slide or piston relocated back. At the end of the compression stroke, the Hegex-Iiocken moves the slide or piston further to a second position in which the inlet for injecting fuel is blocked. A switching device is able to rotate the slide or piston between a starting and a normal operating position. In the starting position, the circumferential surface of the slide or piston blocks the inlet during of his two fuel injections while he is in the normal operating position is rotated in such a way that its circumferential surface the opening only in its further Shift to the second position blocked. The inventive Improvement comprises at least one fuel passage provided in the slide or piston, which connects the circumferential surface with the inner end face of the slide or piston and during the Starting the diesel engine and in the second slide position is in communication with the inlet.

Although special embodiments of the invention are shown and described in detail above, In order to illustrate the implementation of the inventive concept, the invention can of course also be implemented in other embodiments can be realized without deviating from their framework and basic ideas.

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Claims (5)

P a t e η t a η β ρ r ü c h e / 1./ Fuel injection device for a diesel engine, Consists of a slide cylinder with a radial fuel inlet, one in the cylinder axially vex ^ slidably guided slide or piston, one the slider baw. Piston-actuating control cam with distributed on circumferential distances from each other Elevations, which with the slide or piston in | Can be brought into contact and him during the suction or Compression stroke in a first position, in which he opens the inlet for the purpose of injecting fuel blocked, shifting, and then shifting it back able to let, whereby the control cam at the end of the compression stroke the slide or The piston continues to move into a second position, in which it opens the inlet for the purpose of fuel injection blocked, and a switching device that when starting the diesel engine acts on the slide or piston and aligns it in such a way that its peripheral surface during its movement to the first and second positions, the inlet is blocked to allow two fuel injections undertake, and in the liormalbetrieb the diesel engine the slide or piston adjusts so that its circumferential surface only allows the inlet blocked when moving to its second position, characterized in that the slide b ^ w. Pistons (12) at least one passage (23) is provided, which is the circumferential surface of the slide or piston connects with its inner face and when starting the diesel engine in the second slide position communicates with the inlet (22). 009836/1549 BATH 2. Device according to claim 1, characterized in that that a number of passages (23) are provided. 3. Device according to claim 1, characterized in that that the inner end face (11) of the slide or piston (12) is stepped and thus a circumferential surface defines »that when starting able to block the inlet (22) in the first and in the ζ v / ei th position. 4. Apparatus according to claim 1, characterized in that that the inner end face (11) of the slide or piston (12) inclined with respect to its longitudinal axis is trained. 5. Apparatus according to claim 1, characterized in that that a plurality of fuel inlets (23) are provided at different heights in the piston cylinder (8a) are that the cylinder (8a) is enclosed by an axially and circumferentially displaceable sleeve and that the Luise is provided with an opening, the π it a selected one of the fuel-on-load to work together C09836 / 1549 Blank page