DE2009365A1 - Fuel injection device for a diesel engine - Google Patents

Description

■ -20Ό9-365

Mitsubishi Jukogyo Kabushiki Kaisha 2 7, Fek! 3? Ö

Tokyo, Japan - _: "■.: -

Fuel injector 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 both when the engine is being admitted as well as in operation several degrees in front of the upper one Dead center, d, h # at -10 ° to -3 °, during the compression bact.

If the starting ambient temperature is low, can be in a cylinder chamber or a combustion chamber The air present is insufficient because of the low temperature of the gasoline engine and also of the intake air reach high temperature, although the air compresses if OK, the ignition delay is extended and will advance by a few degrees during the injection period the top dead center in the compression stroke shortened during which the fuel droplets in the Compression gray room with high temperature air come into contact. The ignition of the fuel droplets is therefore very difficult.

"" - ■ "- ■■" / ■ In another, already proposed Sieselmasqhi- · nen design is before the actual fuel injection several degrees before top dead center in the compression stroke made an additional fuel injection at the beginning of the compression stroke. With this type of diesel engine is the total amount of fuel injected

009836 / IS4Ö

practically constant both when starting and in operation. This diesel engine should be efficient by improving the combustion conditions of the fuel improved and also the regulation or control of the mode of operation are facilitated.

Although this type of diesel engine has excellent starting properties because of the two-stage additional fuel injection, it still has a disadvantage. Since the second stage of the additional fuel injection follows the first stage and the amount of fuel injected in the first stage is determined by a cam lift of a piston, it is impossible to determine the timing of the start of the fuel injection in the second Stage without changing the amount of fuel injected in the first stage; e and without the sail cam di actuating a piston
to replace the lighter contour »

actuating control cams differentiated by a cam

In contrast, the invention relates to an improved injection device for diesel engines significant improvement in tempering behavior under low temperature conditions.

More specifically, the invention relates to an improvement the diesel engine injection device of the aforementioned type, which has an additional fuel injection works when starting. In this injection device, a cylinder or a piston bore has a fuel inlet and one fore displaceable in the bore guided piston or slide on. A cam serving to actuate the piston points in the circumferential direction so spaced apart elevations that the piston, after being advanced into a first position and returned again during the intake or compression stroke

- 3 -009836/1548

_ 3 ---

has been: is advanced further into a second position at the end of the compression stroke. A switching device is able to rotate the piston through practically 180 ° between a "start" and a "run" position.

In the starting position the force is substance-intake · by the circumferential surface of _a piston is blocked, so that during the movement of the piston in the first and in the second position two fuel injection bursts to be performed. In the operating or running position, the piston is rotated into a position in which the inlet is blocked by its circumferential surface, so that fuel is only injected when the piston is moved into the second position.

According to the invention, a passage is provided in the piston, which is the circumferential surface of the piston with its inner end face located in the bore or in the cylinder connects, and is formed in the cylinder at an angle from the main fuel inlet · fuel st off bypass inlet. In the starting position of the piston this passage communicates with the fuel bypass inlet when the piston enters said second one Position has been advanced. In the operating state of the Diesel engine the piston is rotated to a position in which the passage can no longer communicate with the bypass inlet.

The arrangement according to the invention has the advantage that even if the ambient temperature is too low is to let the intake air reach a sufficiently high temperature, by setting the switching device in the starting position of the fuel uniformly mixed with the intake air for a longer period of time and then heated in the first stage of the additional fuel injection, whereby the ignition delay is shortened so much that an ignition

009836 / t54t ^ " ⁴ "

certainly done. The torque required to crank the diesel engine can be achieved in the second stage the additional fuel injection can be generated. Then with the diesel engine running, while their temperature increases, the fuel injection only occurs when the piston is moved in the second position is carried out by pressing the control or Switching device switched to the "running" position will. The diesel engine then runs smoothly, while the fuel is exactly that for normal operation required amount is injected .. In addition, the injection amount in normal operation compared to the Starting the amount of fuel used can be reduced considerably, thereby reducing the thermal Efficiency is avoided.

More precisely, the interior of the cylinder or the bore in the starting position of the piston in the period between the first and the second position of the piston is connected to the fuel bypass inlet. Thus, both the start time of the injection and the injected fuel quantity can be in the second Injection stage can be set at your discretion by the time at which the bypass inlet through the Piston peripheral surface is blocked, delayed accordingly without the need to change the contour of the cone cam.

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

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

009836/1548

Furthermore, the invention is to create an improved Injection device of the type mentioned achieved at which the injected force— Amount of fuel in normal operation of the diesel engine compared to that injected when the diesel engine was started The amount of fuel can be reduced considerably, so that a reduction in 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 point of the fuel injection and the amount of fuel injected in the second additional injection step ■ without changing the contour 'of a piston actuating the injection piston Control cam and can be set at your discretion without replacing this cam.

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

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

Fig. 2 is a view of another embodiment, similar to the system of Fig. 1, of a previously proposed one Fuel injector,

3 shows a partial side view in the direction of the arrow III-III seen in Fig. 2,

4 shows a longitudinal view on an enlarged scale section of a main part of the device according to FIG. 2 ,. · ";." ■. :

Fig. 5 is a schematic representation of the fuel

00 9836/1146

Injection device according to FIG. 2,

Fig. 6 is a graph showing the relationship between obm cam stroke and the piston when starting or in normal operation of the device

according to Fig. 2,

Fig. 7 is a graphic representation of the principle of operation 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,

Figure 9A is a graph showing the relationship

between the cam stroke and piston when starting or in the no ^ -malbetrieb the device according to Fig. 8,

9B in conjunction with FIG. 9A shows the respective angular positions of the slide or piston during starting and in normal operation or running and

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 the air compressed in a main space b during the upstroke of a piston a flows over a Passage c into an antechamber d, the air at low temperature due to the throttling loss is cooled at passage c in the pre-chamber d, for this reason it is even at the end of the compression stroke difficult to let the air in the antechamber d reach the ignition temperature. When starting must therefore by a fuel injection pump e via a

009836/1548

Nozzle f injected fuel into the prechamber d get into the main room b by having the antechamber d and the passage c flows through. However, since the flow rate the air from the main room b via the passage c is quite high, it is the injected one Fuel jet almost impossible against this Air flow to get into the main room b. For this Grund owns an antechamber diesel engine at low Ambient temperatures have a very poor starting behavior.

In order to improve the tempering behavior, there is already one in the 2 to 7 shown fuel injection device for diesel engines has been proposed (German patent application Akt.-Z. P 19 5? 370.7). With this device a piston 2 is guided to and fro in a straight line in a main space or cylinder, the main space 1 communicates with an antechamber 4 via a passage 3. At the antechamber 4 is one with a nozzle-needle valve 5 provided nozzle 6 provided while a Fuel injection pump housing 8 is connected to nozzle 6 via a line.

In the injection pump housing 8 is an axially linearly displaceable Slide or piston 12 guided with a stepped portion 11, which is under a supply valve housing 10 is arranged, which receives a supply valve 9. The slide or piston 12 is axially through to the housing 8 a control cam 13 displaceable, which is synchronized with the rotation of the diesel engine crankshaft in rotation is moved.

A rack 14 meshes with teeth, not shown on the circumference of the piston or slide 12 and is connected to the one end 15b of a fork lever 15 connected, which is pivotably mounted approximately in its middle part '15a.

009836715 ^} ...

The other end 15c of the fork lever 15 is in contact with a displaceable shaft 16a of a regulator 16. From the middle part 15a of the fork lever 15 is an arm 15 cL which has a spring 17 with a control button 18 is connected. In addition, the injection pump housing 8 is provided with a starter button 19. A fuel inlet 22 is provided on the pump cylinder 8 a within the housing 8.

With this injector, when the control button 18 5 preset in a starting position and the starting button shown in phantom in FIG 19 is brought into the position drawn in solid line in FIG. 4, a protruding from the rack 14 comes Pin 20 is free from a stop 21 so that the rack moves from the normal operating position to the starting position can move. Here, the slide or piston 12 is rotated into a position in which the upper part 11a of the stepped portion or the inner end face 11 of the slide or piston 12 the inlet 22 opposite.

If under these conditions the diesel engine cranks with the help of a known starter, not shown is, the lever cam 13 is rotated counterclockwise according to FIGS. 2 and 5. The slide or piston 12 is formed by a first crouching elevation 13a in the left half of the upper one Section of Fig. 6 shown lifting position 1 ,. in another stroke position 1, shown in the right half of the upper portion of FIG. 6, is displaced. During this side span, the fuel inlet is 22 through the upper part or projection 11a of the inner end face 11 of the slide and / or. Piston 12 blocked. Consequently a first fuel injection is carried out, at which about half of the total Ki '£ .f "C £ -coff to be injected is injected. The time control

_ 9 - 009836/1548

. ; - 9 - ■ ■ '

for-the-lifting of the slide or piston 12 by the first cam lobe 13a is on the end of the Intake stroke or at the beginning of the compression stroke set. For this reason, the one injected during the first injection stage flows into the prechamber 4 Fuel via passage 3 into main room 1. During the compression stroke, this fuel is sufficiently mixed with the intake air and heated to high temperature.

When the first cam elevation 13a has passed the lower end of the slide or piston 12, the latter shifts so far downwards that the fuel inlet? injection is interrupted. A second cam lobe 13b then comes into contact with the lower end of the slide or piston 12 and lifts the latter, a second fuel injection stage being initiated when the slide T? Zw. Piston 12 has reached stroke position I ₇ . Meanwhile, the temperature tm (J ¹ Ig. 7) of the gas mixture of fuel iond air in the main room Λ increases above the temperature tp in the antechamber 4. The gas in the main chamber 1 can therefore be ignited more easily than that in the antechamber 4. In addition, the fuel injected during the second stage flows at least partially into the main space 1 at the moment in which the flow velocity zp through the passage 3 is reduced, the fuel flowing through the passage 3 burning with the gas mixture and. thus provides the explosive force required for starting, so that the diesel engine can be started very easily.

As soon as the diesel engine reaches a predetermined speed has, "the centrifugal force of a weight 16b mounted on the regulator moves the displaceable shaft 16a of the Controller in the direction of the arrow according to Fig. 5

- 1Q 009836/1548

- ίο -

The rack 14 is moved by the fork lever 15 sen and the slide or piston 12 is rotated through an angle of 180 °, so that the lower part 11b the grooved or stepped inner end face of the slide or piston 12 opposite the fuel inlet 22 comes to rest.

Even if the slide or piston 12 arrives in the lift position I ^ under these conditions under the influence of the first cam elevation 13a, no injection can be carried out because the inlet 22 has not been blocked. _{Only when the slide or piston 12 reaches the lift position I 2} under the influence of the second cam elevation 13b is the fuel inlet 22 blocked by the lower part 11b of the stepped inner end face 11 of the piston or slide 12, see above that the fuel can be injected. In order to maintain normal operation of the Mesel machine, a smaller amount of fuel is injected than when starting the machine, similar to a conventional Biesel machine.

Even if the diesel engine has not reached the predetermined speed when the Hegel knob 18 has been set to the normal operating position, the piston or slide 12 is rotated and adjusted so that the lower part 11b of the inner end face 11 is opposite the on- * let 22 is located.

In the already proposed fuel injection device according to Jj ¹ Ig. 2 to 7 can be changed by changing the height of the stepped section of the inner end face of the piston or slide 12 or the stroke height I ^ and I ₇ . 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, while the total amount of fuel injected during starting

- 11 009836/1548

the amount of fuel to 150 - 300 # that for maximum performance fuel quantity injected during normal operation can be adjusted.

As mentioned, the already proposed injection system according to FIGS. 2 to 7 ensures better engine behavior or better performance than a direct injection diesel engine when starting 3 is low, a first injection stage is carried out so that the fuel can get into the main space 1 in sufficient quantity and the ignition in the main space 1 can take place at a higher temperature than that of the compressed air in the antechamber 4-.

However, since the second stage of fuel injection is in begins the moment in which the slide or .. Piston 12 moves upwards again and arrives in Kosken stroke position 1, after it has initially been lifted into stroke position Ii and moved back again, and since the amount of fuel injected in the first Stage is determined by the stroke positions 1. and 1, it is impossible to determine, in an expedient manner, the starting point of fuel injection during the second Allocate the injection stage without changing the injection quantity in the first ötufe to vary and without the rule-loosen 13 to be replaced by another with a different contour.

8, 9A and 9B, a fuel injector is the one used in the Pig. 2 to 7 shown Modified kind in such a way that in the slide cylinder 8a at a in a horizontal plane by 90 from. Main fuel inlet 22 remote point a force-

. ; - 12 00 9 836/1 5-4 ö "

material bypass inlet <.23 is provided. In this context reference is specifically made to FIG. 9B, since 3? ig. 9A shows a development instead of an actual section to illustrate the interrelationship between main inlet 22. FIG and bypass inlet 23.

In addition, the slide or piston 12 is provided with a connecting path or passage 24 such that the fuel bypass inlet 23 provided in the slide cylinder 8a and the interior of the slide cylinder 8a located inward of the inner surface of the slide or piston 12 communicate with each other when the slide or piston 12 is in the stroke position 1 and has been rotated into its starting position. When the slide or piston 12 has therefore been rotated into its starting position so that the stepped upper part 11a of the stepped section 11 is opposite the main fuel inlet 22, one is on the circumferential surface, as indicated in the upper half of FIG. 9A of the slide or piston 12 provided _t the opening 2PrB corresponding to the passage 24. in the same vertical or axial plane as the bypass inlet 23. "When the slide or piston 12 is in the stroke position; I ₇ StelluTir. ej .--- oicl: l-, icoiamuniz-ieren as a result of the actuation of the LJci. io ^ ca ·; -; b:; \ '.' ..α.Ι · <-: - ηκ durcn oie I'ooken-iSrhebunß 13ε. der οLο:; .. ·· r "i ■■ yry .: - - ■:> iiv _: ... C; Λ nu ^ rZ ^ liAidor ca and bypassing, ':: - ei.:- I; ■; ^: '~. · - :::. ·. · ■■. 7Ju: r ⁱ c ^: _;: vn; = :? Λ ΜΠ, -iv-iivif.nder,

beibot; \ -eviii oyin the slide bav / *; loibt; r> 12 through the zv.'cit-e ic-clvSu-LrVi ^ riung 13b something out of the stroke position 1-, raised vdra, v / i?: d die ': ; v / tite Ctufe dar fuel ΐϋη.: ·;: Γΐΐ :: ϋ;. · Γ: first dax:} :: introduced _t from the on the Una : ~. \ j : f :. ' r. ■■ -ϋΐ: -; ^^ !, iebev'- btv /. liclbenn 12 provided · ': ·

r; -

009836 / 15A8

has been. In the stroke position l ^, corresponding The position of the slide or piston 12 is the connection between the upper space in the cylinder 8a and 8a the bypass inlet 23 interrupted, so that the second fuel injection stage is initiated.

If however.der slide or piston 12, as in the lower one Half of Fig. 91 and 9B shown, rotated to switch to normal operation by 180 ° and the on 'the Circumferential surface of the slide or piston 12 lying Opening 24a of the passage facing away from the bypass inlet 23 and also at a right angle to Main inlet 22, there is no possibility that the upper space in the cylinder 8a with the main inlet 22 or communicates with the bypass inlet 23 until the Slide or piston 12 in one of the cam lift position Ip corresponding position arrives. The start time the fuel injection and the injection quantity im Normal operations therefore do not differ from the corresponding values in the case of a lack of passage 24 and are therefore kept constant.

In this embodiment of the invention, the starting time the fuel injection and the power injected during the second stage when starting - amount of substance in a very simple and practical way Change in diameter or height or both dimensions the opening 24a lying on the circumferential surface of the slide or piston 12 can be adjusted without changing the shape of the cam lobes 13a and 13b to change. This ensures fuel injection after starting, which optimal "to the different characters characteristics of the diesel engine, such as starting behavior, output power, "noise generation, etc., is coordinated, so that the performance of the diesel engine is improved will.

- ■ 14. -

'-.V. ^ ,, .., .- 009836/154 8

In a modified embodiment of the invention, the fuel bypass inlet 23 can instead of under one Right angle to the main fuel inlet 22 at a ■: the main inlet 22 diametrically opposite point arranged in the slide cylinder 8a and at the same height as in the embodiment described first be. In this case, the schematic representations in the lower left section of Fig. 9A could be seen as matic longitudinal sections of the fuel injection pump instead of developments, as previously mentioned, viewed will. If in this modified embodiment of the invention, the slide or piston 12 in the manner is provided with the passage 24 that the latter connects the interior of the slide cylinder 8a with the bypass inlet 23 in the position in which the slider Mw. Piston 12 is in stroke position 1 and has been rotated into the starting position, and the slide or piston 12 through 180 ° into the normal operating position is rotated, even if it is in a position corresponding to the cam lift position Ip arrives, in v / elcher the circumferential surface of its lower stepped portion 11b blocked the main inlet 22, the fuel injection due to the presence of the passage in the stroke position 1 ~ not initiated, since the interior of the cylinder 8a and the Main inlet 22 are connected to one another via the passage. This is in contrast to an arrangement at which the passage 24 is not provided, so that the injection is initiated in the cam lift position I ^ will. Only if the opening 24a of the passage upward has come out of the main inlet 22 and consequently the connection between the main inlet 22 and the interior of the slide cylinder 8a is interrupted has been, the fuel injection is carried out for normal operation or initiated with a delay.

- 15 -009836 / 1548 ^ _oWG INAL

-.15-

In this way, in the modified version form of the invention not only the injection when starting, but also the injection timing and the Injection quantity can be easily adjusted in normal operation. ·

In the embodiment according to FIGS. 8 and 9 (A, B), a stepped or notched section 11 is provided. The same mode of operation and the same advantages can, however, also be achieved if the upper or inner end face of the slide or piston 12 according to FIG. 3. 10 cut obliquely and the passage 24 is designed so that the opening 24a comes to rest on the side located at the higher end of the inclined end face of the slide or piston 12.

Instead of end faces of the slide or piston at different heights. 12 to provide on the relevant sides, the top of the same can optionally also be perpendicular to its longitudinal axis, while several fuel inlets 22 are provided at different heights on the slide cylinder 8a and a sleeve is arranged around the outer circumference of the cylinder 8a, which both is axially and circumferentially freely displaceable. By optionally shifting an opening formed in the sleeve into a position opposite one of the various inlets 22 , a two-stage injection during starting and a single-stage injection during normal operation can be achieved . two or more passages can also be provided®

In summary, the invention therefore creates a fuel -Injection device for a diesel engine that a valve-üyünaei- with a fuel inlet and

-16 0 0 9 8 3 6/154

a slide axially displaceable in this cylinder or piston. An ilen slide or piston actuating Control cam has two elevations for actuating the slide or piston. During the The intake or compression stroke, the cone cam moves the slide or piston into a first position, in which it blocks the inlet for injecting fuel, whereupon the slide or piston closes. relocated back. At the end of the compression stroke, the control cam moves the slide or piston further into one second position in which the inlet for injecting fuel is blocked. A switching device

P is able to rotate the slide or piston between a starting position and a normal operating position. In the starting position the circumferential surface of the slide or piston blocks the inlet during its two fuel- Injection strokes while in the normal operating position is twisted in such a way that its peripheral surface is the opening blocked only when it is further shifted to the second position. The improvement of the invention comprises at least a fuel passage provided in the slide or piston, which connects the circumferential surface with the inner Front face of the slide valve or piston connects and during the start of the diesel engine and in the second

^ Slide position with one provided in the slide cylinder Bypass inlet communicates which is angularly removed from the main fuel inlet.

Although special embodiments of the invention are shown and described in detail above, In order to clarify the realization of the inventive idea, the invention can of course also be used in others Embodiments are realized without deviating from their scope and basic ideas.

- 17 009836/15 4 8

Claims (7)

Claims 1.1 fuel injection device for a diesel engine, Consists of a slide cylinder with a radial fuel inlet, one in the cylinder axially displaceable slide or piston a control cam which actuates the slide or piston and is distributed over circumferential distances from one another. th elevations that can be brought into contact with the slide or piston and move it into a first position during the intake or compression stroke which it blocks the inlet for the purpose of injecting fuel, move it and then close it - able to shift back, with the control cam at the end of the compression stroke the slide or piston brings further into a second position, in which he blocks the inlet for the purpose of fuel injection, and a switching device that at Starting the diesel engine acts on the slide or piston and aligns it angularly in such a way that that its peripheral surface during its movement in the first and second positions block the inlet for two fuel injections, and which in the normal operation of the diesel engine adjusts the slide or piston angularly so that its circumferential f laugh the inlet is only blocked when it is moved into its second position - marked by this - (Oa-) net that in the slide cylinder in addition to the radial Fuel inlet (22) a radial fuel bypass inlet ($ 2) and. at least one passage (24) in the piston or slide (12). are provided which the circumferential surface of the slide or piston (12), connects with its inner face and when - 18 009836/1548 let the diesel engine communicate with the bypass inlet (23) in the second slide position, 2. Device according to claim 1, characterized in that that the radial fuel bypass inlet (2J) is about 90 ° from the first-mentioned radial fuel inlet (22). 3 · The apparatus of claim 1 _t wherein the radial fuel bypass inlet is arranged (23) offset by an angle of 180 ° to the former radial fuel intake (22). 4. Apparatus according to claim 1, characterized in that that several passages (24) are provided. 5. Apparatus according to claim 1 _t, characterized in that the inner end face of the piston or slide (12) is stepped by defining a circumferential surface which is able to close the fuel inlet (22) when starting in the first and second positions. 6. Apparatus according to claim 1, characterized in that that the inner end face of the slide or piston (12) cut obliquely to its longitudinal axis is. 7. The device according to claim 1, characterized in that in the slide cylinder (8a) a plurality of fuel -Inlets (22) are formed at different heights that the cylinder (8a) from one axially and circumferentially displaceable sleeve is enclosed and that the sleeve is provided with an opening is that with a selected one of the fuel inlets able to work together. -19 - 009836/1548 Device according to Claim 1, characterized in that the radial fuel bypass inlet (23) is arranged angularly away from the first-mentioned fuel inlet (22). 009836/1548 Blank page