DD144433A1 - AIR COMPRESSIVE, DIRECT INJECTIVE INTERNAL COMBUSTION ENGINE - Google Patents

Description

Air-compressing, direct-injection internal combustion engine Application end of the invention

The invention relates to an air-compressing, direct-injection internal combustion engine with a rotationally symmetrical, arranged in the piston or cylinder head, a constricted against its largest diameter neck having combustion chamber in which a rotating around the combustion chamber longitudinal Luftbev / egung, and in which the liquid fuel over an eccentrically arranged, load and speed-dependent controlled multi-hole injection nozzle is injected in such a way in the direction of air movement in the combustion chamber, that on the combustion chamber wall, the formation of a fuel film is possible.

The invention is applicable to all air-compressing, direct-injection reciprocating internal combustion engines.

Chara kteristik the most ten technical rule Solutions

Such an internal combustion engine as described above is

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already known from DE-PS 865 683. In her the fuel with the shortest possible free jet length is applied to the combustion chamber wall to limit an immediate mixing with the air to a necessary only for the ignition minimum »The impact of the fuel, rays is therefore on the upper half of the combustion chamber wall ·

It has been shown sijch soon that in such an injection method at idle and in the lower and middle part load of the engine a disturbing environment, eyes and respiratory irritant Blaurauchbildung occurs. The reason for this Blanrauchbildung is for a good combustion too low temperature of the combustion chamber wall · Poor combustion promotes the formation of aldehydes, acrolein, special hydrocarbons and other in the exhaust gases *

To remedy this evil, it is already known according to DE-AS 1 020 210 to destroy the air swirl partially or completely or even to change the lease of the fuel jets such that the proportion of directly with the Air mixing fuel is increased. Further, it has already been proposed to increase the compression ratio or to extend the fuel injection time in the lower speed range, in order to prevent a pronounced fuel jet formation »so that a larger direct air-fuel mixing takes place.

Although such measures achieve a corresponding reduction of the blue smoke or the irritating substances in the waste gases, they are unsatisfied in this respect.

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because the extra resources required to do so make it more expensive and at the same time more prone to failure, or because some deterioration of the engine operating data in the upper load ranges, especially at full load, can not be avoided «.

Furthermore, it is known from DE-PS 2 038 048, when using a ball combustion chamber, the ratio see between combustion chamber diameter and opening diameter to a certain value and to lay the point of impact of only a fuel jet in the lower quarter of the combustion chamber wall, which also Ratio of the circumferentially rotating air charge was fixed to the axial velocity of the piston. The purpose of these measures was to mix as much of the injected fuel as possible in the operating ranges described directly with the combustion air and to apply the smallest possible proportion as PiIm on the relatively cold combustion chamber wall. However, one measure, namely the jet position, is no longer defined if the spherical combustion chamber is left in favor of another rotary body-shaped combustion chamber.

Object of the invention

The aim of the invention is to provide an air-compressing, direct injection internal combustion engine with higher utility value characteristics.

Explanation of the nature of the invention

The invention is based on the object of further advancing an internal combustion engine of the type described above.

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zuentwickeln that the best possible reduction of blue and white smoke formation is achieved without increasing the cost and without a precise definition of the fuel spray positions and without deterioration of the operating data in the upper operating range with largely free choice of the combustion chamber shape at idle and in the lower and middle.

After

Invention, the object is achieved in that

an injection nozzle is used in which the fuel control member in the lower speed and / or load range of the engine only one or a few injection holes, and in the upper speed "and / or load range a second or a further number of fuel holes releases that the ratio of the largest Brennraumdurchmessers to the diameter of his neck between 1.05 and 1.25 is that the rotational frequency of the rotating air - based on the measuring diameter (0.7 cylinder diameter) and maximum valve lift and 10 m / s.ec average piston speed - between 135 and 185 Hz and that the .Einspritzdauer - based on full load at the smoke limit - at an average piston speed of 10 m / sec over more than or at least 20 ° crank angle extends.

Thus, a hole nozzle is also used for the fuel injection, whereby no installation difficulties occur because the injection holes of almost every combustion chamber configuration can be adapted. A coking of the injection holes is also largely eliminated, because the injection sequence is separated exactly »

By injecting the fuel in two stages, it is easily possible at idle and in the lower and possibly.

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In the middle operating range of the engine to achieve a substantial or even complete direct fuel-air mixture, so that the disadvantages caused by the still insufficiently heated combustion chamber wall are turned off. In the upper operating range, however, the fuel is still predominantly film-like applied to the combustion chamber wall, where it is evaporated, mixed with the rotating air and finally burned · Vielter brings the gradufth fuel injection has the advantage that even in the full load range at low speeds, the combustion too In favor of a low black smoke and low fuel consumption and in the high rev range in favor of low ignition pressures and fuel consumption. Custom, for example, when charging, can be improved by only a portion of the spray holes is released in an analogous manner in the lower range of rotary speed, in the upper but the full spray cross-section.

In order to obtain good engine data in all operating ranges, it is also necessary in conjunction with the two-stage fuel injection to precisely tune the air swirl, determine the most favorable ratio of the largest combustion chamber diameter to the diameter of his neck and the rotational frequency. Finally, with the air swirl, it is necessary to tune the fuel injection duration in order to optimize mixture formation. The opening ratio between the largest combustion chamber diameter to his neck is mainly dependent on the location and cross-sectional distribution of the at least two injection holes, depending on the requirements in terms of speed, power output, torque and possible charging of the internal combustion engine, the rotational frequency of the air is selected. The jet position, in particular in the direction of the combustion chamber axis _9, is below the given

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called determinations no longer so restricted as before. A far-reaching variation is now possible. "The only prerequisite is that the first fuel jet does not spray over the combustion chamber or does not emerge during the injection time and the lowest jet does not reach the combustion chamber floor. At least one jet at full load of the engine, when all spray holes are released, near the equator near or just below impinge on the combustion chamber wall, of course, the combustion chamber shape, whether ball, ellipsoid or the nozzle outlet guide are authoritative. This beam or these rays should include at least half of the total injection quantity and in the circumferential direction of the air vortex affect the combustion chamber wall and form the known film on it, while the other beam or the other rays with at most half the injection quantity depending on the conditions of the Twisting direction and thus can deviate from the wall tangent in order to achieve the desired effect of greater direct air mixing at partial load. "

In a further embodiment of the invention, it was found that the use of certain injectors is very advantageous because they are easy despite their proper function in their construction · and easy to install in the cylinder head, and because the spray holes can be easily attached to the respective requirements at any time. In this regard, it is proposed that the coming to use the injector as a fuel control member axially displaceable in a nozzle body, held by at least one spring on its sealing nozzle nozzle needle, that the first opening spray hole or the injection holes open into a Mngrauni below the sealing seat, and that in the upper speed and / or

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Load range opening spray hole or the injection holes with a provided below the annular space blind hole are in communication, immersed in a designed as an extension of the nozzle needle cylindrical pin.

In the lower speed and load range, the nozzle needle is lifted against a spring only a small part of the sealing seat, so that a partial fuel injection takes place through the or in the annulus opening injection holes. With increasing engine speeds and loads also increases the pressure in the injection line and thus in the annulus, the nozzle needle is lifted against a second spring further until the provided on her cylindrical pin releases the blind hole and finally also or the opening into this orifices with ' Fuel be applied. Thus, the full injection cross section is available. The full spray cross-section of all spray holes corresponds to the flow rate that would have been achieved by using a one-hole nozzle which has a spray hole, it being noted that the cross-sectional distribution onto the individual spray holes can be made arbitrarily, ie. that a spray hole or some spray holes can have larger and other smaller cross-section. In this way, in the described lower speed or Lastbereich.des engine is achieved that can build up by increased throttling sufficiently high line pressure to release the corresponding injection cross-section in the first stage of Hadelhubes and a. Otherwise unattainable fuel atomization occurs, which, favored by a selectable jet position, can run off more air-distributing and thus prevents intensive 7 / and- accumulation, without being at full load in the middle

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and upper speed range, ie. with increasing rotational frequency and thus centrifugal force of the air vortex and then wall tangentially splashing main beam or -radiation the desired Wandanlagerung is avoided.

In a further concrete embodiment of the invention, it is provided that the opening in the upper speed and / or load area injection hole or the injection holes are aligned so that they spray the fuel in the direction of the air swirl tangential to the combustion chamber wall near the equator on this, and that the injection hole cross-section at least half of the total injection quantity is produced «

It is expedient in this context, further, if the opening in the lower speed and / or load area injection hole or the injection holes are oriented so that they inject the fuel from the direction of the air swirl deviating in the combustion chamber, and that the injection hole cross-section at most half of the total Injected amount promoted

According to the invention, the injection nozzle used as a fuel control element can be displaced axially in a nozzle body by at least one injection nozzle. Spring having held on its sealing seat nozzle needle, and that the first opening spray hole or the injection holes open into a blind hole below the sealing seat, that the opening in the upper speed and / or load area injection hole or the Spritslöcher provided with a needle guide in the nozzle body recess be in communication, which can be acted upon by a control edge on the nozzle needle after a certain Nadelhub »

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It has also been found to be advantageous if the injection nozzle used as the fuel control element has two nozzle spindles arranged parallel to one another and axially displaceable by springs on their sealing seats, one of which lifts off from its sealing seat even at low fuel pressure, while the other releases the fuel only when the engine is running in the upper speed and / or load range.

embodiment

The invention will be explained in more detail by exemplary embodiments v / ground. In the accompanying drawing show:

1 is a longitudinal section through the upper part of a arranged in a cylinder piston with marked fuel jet configuration according to the invention,

2 is a plan view of the piston after a section H-II in Fig. 1,

3 shows a section HI-III through the arrangement according to FIG. 2

4 shows a longitudinal section through the lower part of an injection nozzle proposed for the invention,

5 shows a longitudinal section through a part of the spring combination acting on the nozzle needle according to FIG. 4,

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and FIG. 7 each show a longitudinal section through the lower part of further injection nozzles which are suitable for the invention.

In äen Pig »1 to 3, a piston 1 shown only in part in its piston head 2 a spherical combustion chamber 3 here with a diameter D. The combustion chamber 3, which may also have any other rotationally symmetrical shape, is connected to the interior of the cylinder 5 by a neck 4 constricted to a diameter d. A spout 6 in the neck 4 is used for injection of the fuel through an injection nozzle 7, which is arranged obliquely in the cylinder head 8. The ratio of the combustion chamber diameter D to the diameter d of the neck 4 is referred to as opening ratio <f and has the value 1.05 ^ " cT ^ r T,

The equatorial plane of the combustion chamber 3 is indicated by a dot-dash line 9 and half of the lower part of the combustion chamber 3 by a likewise dash-dotted line 10 * Lines 11 and 14 show the direction of two geometric fuel jets according to the invention at ₉ at the point 15 and Axially extended theoretically impinge on the combustion chamber wall at the impact point 12. The impact point 15 is slightly below the equatorial plane, while the Vorstrahl, which is indicated by the line 11, atomized and ruptures in the lower speed and partial load of the engine so that he-the combustion chamber wall 13 gar.nicht not reached, but before close to the wall burns in the upper speed and load range, however, is centrifuged by the higher Drehfrequeriss the air swirl 16 to the wall and there zusanimen with the indicated by the line 14 main beam slightly lower

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half of the impact point 15 forms a fuel film.

In Pig. 4 and 5, a part of a nozzle body 17a is shown, which has a bore 17b for receiving a nozzle needle 18. Downwardly, the bore 17b narrows and the resulting inclined surface forms the sealing seat 19 to which the nozzle needle 18 is at rest sealingly rests.

• Below the sealing seat 19, an annular space 20 is provided, in which in Fig. 4 at an angle to the nozzle longitudinal axis χ extending injection hole 21 opens. Finally, the bore 17b ends in a blind bore 22, which is closed in the rest position shown by a cylindrical pin 23 forming an extension of the nozzle needle 18. , From the Sacklochbchrung 22 from another injection hole 24 leads through the nozzle body to the outside and ends in the conical surface 25 ·

According to Pig. 5, the upper part of the nozzle needle 18 is mounted axially displaceably in the nozzle body 17a. On the nozzle needle 18 is a mushroom piece 26, on which a changing ens to a holder, not shown, supporting spring 27 presses. A larger diameter retaining spring 28 acts on a Pederteller 29, which extends over a collar 26a of the mushroom piece 26 and in the direction of the nozzle longitudinal axis χ a game 30 to the collar 26 a ·

If fuel is supplied to the injection nozzle, si.ch first shifts the nozzle needle 18 counter to the force of the peder 27 until the clearance 30 is zero. Thus, the injection hole 21 (Pig * 4) comes into action. In the upper La3tbereich or ··· at full load of the engine, the pressure in the annulus 20 increases,

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until it overcomes also the force of the second spring 28 and opens the nozzle needle 18 up to its maximum stroke, where the pin 23 releases the blind bore 22 and thus the injection hole 24 «

FIG. 6 also shows a nozzle body 17a, a nozzle needle 18, a sealing seat 19, a blind bore 22 and injection holes 21, 24. Even within the needle guide jji1, the nozzle needle 18 has a paragraph 32 serving as a control edge, which opens a recess 33 in the nozzle body 17a when the nozzle needle 18 is fully open, into which the injection hole 24, which is to be regarded as the main injection hole, opens. The embodiment differs from that of FIG. 4 mainly in that the so-called. Hauptpritzloch 24 is further away from the nozzle tip, as the first released spray hole 21st

Finally, in FIG. 7, the control function is taken over by two independent nozzle needles 18a and 18b arranged in parallel in the nozzle body 17a and serving the two injection holes 21 and 24. The principle of partial-load injection at low speeds and full-load injection at higher speeds is the same «

Claims (7)

10,9,1979 WPP02B / 213 623 55 668 27 Invention claim 1 · air-compressing, direct injection internal combustion engine with a rotationally symmetrical, arranged in the piston or cylinder head, a constricted against its largest diameter neck combustion chamber, in which a rotating around the combustion chamber longitudinal air movement prevails, and in which the liquid fuel via an eccentrically arranged, load and speed-dependent controlled multi-hole injection nozzle is injected in the direction of air movement in the combustion chamber, that on the combustion chamber wall, the formation of a fuel film is possible, characterized in that an injection nozzle is used, wherein the fuel control member in the lower speed and / or load range of the engine only one or a few injection holes (21) and in the upper speed and / or load range a second or a further number of spray holes (24) releases the ratio ( (f ) of the largest combustion chamber diameter (D) to the diameter (d) of its neck (4) is 1 _r 05 and 1.25 (1.05 ^ cT ^ T 1.25) that the rotational frequency (fl) of the rotating air - based on the measuring diameter (0.7 cylinder diameter) and maximum valve lift and 10 m / sec mean piston speed -r between 135 and 1.85 Hs (135 ^ "fl ^ 185) and that the injection duration - based on full load at the smoke limit - at an average piston speed of 10 m / sec for more than or at least 20 ° crank angle (= 20 ° CA). 2 »Internal combustion engine according to item 1, characterized in that the injection nozzle used as a fuel control member axially in a nozzle body (17 a) 10.09.1979 WPF02B / 213 623 '55 668 27 slidable, by at least one spring (27 »28) held on its sealing seat (19) nozzle needle (18), that the first opening spray hole (21) or the spray holes in an annular space (20) open below the Bichtsitzes (19), and in that the injection opening (24) or the injection holes opening in the upper speed and / or load range are in ¥ connection with a blind hole (22) provided below the annular space (20), in which a cylindrical journal designed as an extension of the nozzle needle (18) ( 23) immerses » 3 * internal combustion engine according to item 1 and 2, characterized in that when opening the nozzle needle (18) against the force of a spring (27) after a certain partial stroke, a second spring (28) is switched on, which supports the first spring (27). 4 · Internal combustion engine according to item 1 to 3, characterized in that the opening in the upper speed and / or load area spray hole (24) or the injection holes are aligned such that they the fuel in the direction of the air swirl (16) tangentially to the combustion chamber wall - ( 13) in the vicinity of the equator, and that the spray hole cross-section conveys at least half of the total injection quantity. Internal combustion engine according to item 1, characterized in that the spray hole (21) or the fuel holes opening in the lower speed and / or load range are aligned such that they deviate the fuel from the direction of the air swirl (16) into the combustion chamber (3 ) fts its · 10.9.1979 WPF02B / 213 623 55 668 27 inject, and that the injection hole cross-section promotes more than half of the total injection quantity. 6. Internal combustion engine according to item 1, 4 and 5, characterized in that the injection nozzle used as a fuel control member axially displaceable in a nozzle body (17 a) by at least one spring on its sealing seat (19) held nozzle needle (18) , and that the first opening spray hole (21) or the spray holes in a blind hole (22) open below the sealing seat (19) that the injection hole (24) opening in the upper speed and / or load region or the injection holes with a recess (33) provided in the region of the needle guide (31) in the nozzle body (17a) Connection are connected, which after a certain ITadelhub by a control edge on the nozzle needle (18) can be acted upon. 7. "Internal combustion engine according to item 1, 4 and 5, characterized in that the - coming to the application injector as fuel control two mutually parallel, axially displaceable in a nozzle body (17a), held by springs on their sealing seats nozzle needles (18a, 18b) of which one already at low fuel pressure from their .Dichtsitz ab-. lifts while the other one releases the fuel only when the engine is running at high speed: - and / or load range ·