DE102015015844A1 - Injector for direct injection of fuel - Google Patents

Abstract

The invention relates to an injector (14) for direct injection of fuel into a combustion chamber (10) of an internal combustion engine, in particular for a motor vehicle, having at least one first ejection opening (24) for direct injection of the fuel, with at least one second ejection opening (26) direct injection of the fuel, and valve means (30) for releasing and closing the ejection orifices (24, 26), the valve means (30) being adapted to inject the first ejection orifice (34) for injecting a first amount of fuel to a first one Timing and the second ejection opening (26) for injecting a relation to the first amount smaller, second amount of the fuel at a different from the first time to release second time.

Description

The invention relates to an injector for the direct injection of fuel into a combustion chamber of an internal combustion engine according to the preamble of patent claim 1.

Such an injector is for example already out of the DE 26 56 276 A1 as known and has at least a first ejection opening for direct injection of the fuel and at least one second ejection opening for direct injection of the fuel. The ejection openings are thus outlet openings or nozzles, which are also referred to as ejection nozzles or injection nozzles. Fuel which is supplied to the injector and is initially located in the interior of the injector can be ejected from the injector into its surroundings via the ejection openings, whereby the fuel flowing through the ejection openings is for example injected directly into the combustion chamber.

Furthermore, the injector comprises a valve device for releasing and closing the ejection openings. The valve device is movable, for example, relative to a housing of the injector, wherein the ejection openings can be released and closed by moving the valve device relative to the housing. If the valve device releases the ejection openings, the fuel can flow through the ejection openings and thus flow out of the injector, whereby the fuel is injected directly into the combustion chamber. Such an injector is used for example in a gasoline engine with direct injection. Furthermore, it is conceivable to use the injector in a diesel engine.

In modern internal combustion engines both injectors with magnetic and piezoelectric drive are used. By means of the magnetic drive or by means of the piezoelectric drive, the valve device may for example be moved relative to the housing, thereby controlling the release and closing of the ejection openings or set. Especially at operating points with charge stratification (DES) or partial stratification (HOS), the requirements for an injector are particularly high. A major requirement here is the targeted introduction of the fuel, the so-called spray targeting, or quantities of the fuel. Usually, the injection of the fuel into the combustion chamber is at least approximately rotationally symmetrical to a central axis, in particular the longitudinal center axis, of the combustion chamber. If the combustion chamber is designed as a cylinder, it has, for example, at least substantially the shape of a straight circular cylinder, so that the longitudinal central axis of the cylinder is also referred to as the cylinder axis. The injection of the fuel, which is at least approximately rotationally symmetrical with respect to the cylinder axis, is advantageous for good mixture homogenization in a non-stratified operation or in a non-stratified combustion process.

Object of the present invention is to further develop an injector of the type mentioned that a particularly advantageous operation of the internal combustion engine can be realized.

This object is achieved by an injector having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

In order to further develop an injector specified in the preamble of claim 1 type such that a particularly advantageous operation of trained as reciprocating internal combustion engine internal combustion engine can be realized, it is inventively provided that the valve means is adapted to the first ejection opening for injection releasing a first amount of the fuel at a first time and the second ejection opening for injecting a second amount of the fuel lower than the first amount at a second time different from the first time. This means that the first ejection opening is designed to inject the larger, compared to the second set, first amount, so that by means of the first amount or by means of the first ejection opening an advantageous or sufficient mixture formation can be realized in the example formed as a cylinder combustion chamber. The second ejection opening is designed for injecting the second quantity which is smaller than the first quantity, so that, for example, by means of the second quantity or by means of the second ejection opening, a so-called ignition injection can be realized. The invention is based in particular on the finding that the injection of a very small amount of fuel is advantageous, especially in partially stratified operation (HOS), in order to realize an ignition injection and consequently emissions, in particular nitrogen oxide (NO _x ) emissions To keep internal combustion engine particularly low. Through the implementation of the ignition injection, particularly in partially layered operation, ie in a partially stratified combustion process, a very good combustion of a force-air mixture accommodated in the combustion chamber can be realized, so that in particular the nitrogen oxide emissions can be kept low.

During an endangered operation of the internal combustion engine takes place in the combustion chamber ignition of the fuel-air mixture, which is ignited in an ignition area or at an ignition point. In particular, the fuel-air mixture is ignited, for example, by means of at least one spark, wherein the spark is generated by means of an ignition device, in particular in the form of a so-called spark plug. Alternatively, another technique for igniting the fuel-air mixture can be used in this case, such as an ignition by corona or laser.

In conventional injectors, the fuel is injected both in the direction of ignition, that is, in the direction of the spark plug or corona, as well as in a direction opposite to the ignition direction. This is the case in particular with a so-called A-gland with conical shape and / or with an MLV cone of rays. However, the fuel injected in the direction opposite to the ignition is needed only to realize a homogeneous main injection, but not for an ignition injection. It is therefore provided to release the second ejection opening in order to realize the ignition injection, while the first ejection opening is closed or fluidly blocked by means of the valve device. This means that the release of the ejection openings at the different points in time means that one of the ejection openings is released by means of the valve device, while the other ejection opening is closed by means of the valve device. As a result, it is possible, for example, to inject the second quantity of the fuel into the combustion chamber via the second ejection opening, while injecting fuel over the first ejection opening is omitted. Thus, by means of the injector according to the invention an ignition injection can be carried out without simultaneously carrying out an injection for mixture formation.

The injector has a plurality of ejection openings, which are also referred to as outlet openings or injection holes. The idea on which the invention is based is now to design the injector in such a way that only a single, that is, exactly one or more injection holes - but not all injection holes - are opened for the ignition injection and thus the fuel is directed toward the ignition, that is, to inject at the ignition point or in the ignition area and thus introduce the fuel at a so-called Zündort. This fuel is the aforementioned second amount of the fuel because the second amount of the fuel is injected via the at least one second ejection port, while the at least one first ejection port is closed by the valve device. Depending on the embodiment, the opening times of the first ejection opening and the second ejection opening may also overlap, so that at least secondarily fuel can be injected via both ejection openings.

This can be realized constructively, for example, by a partial lift of a valve element of the valve device, so that the valve element only partially and not completely opens, for example, first to release the second ejection opening and thereby close the first ejection opening. Furthermore, the use of at least two separate or relatively movable valve elements is conceivable, which are designed for example as a valve tappet. These valve elements may be concentric or parallel or juxtaposed. In this case, for example, one of the valve elements is opened to release the second ejection opening, while the first valve element is closed and thereby blocks the first ejection opening. Furthermore, the use of a valve element for blocking and releasing both ejection openings is conceivable, wherein this valve element is movable, for example, in two opposite directions of movement, thereby releasing, for example, the second ejection opening while fluidly obstructing the first ejection opening or vice versa.

In order to be able to inject the fuel or the respective quantities in a particularly suitable manner, it is provided in one embodiment of the invention that the ejection opening differ from each other in their respective flow cross-section which is permeable by the fuel. The flow cross sections may differ, for example, in their shape and / or in their size from each other. Furthermore, the ejection openings may differ from each other in their arrangement and / or function and / or injection direction. In this case, for example, the second ejection opening is aligned with the ignition region described above, so that the second amount of the fuel can be selectively introduced into the ignition range, thereby realizing the ignition injection described above. The ignition injection is carried out in particular during a partially stratified operation or combustion method of the internal combustion engine. In other words, the invention also includes a method for operating an internal combustion engine, the method being an operating method. Here, the internal combustion engine is particularly designed as a reciprocating engine, in particular reciprocating internal combustion engine, wherein the internal combustion engine may be formed, for example, as a gasoline engine with direct injection. In particular, the internal combustion engine is part of a drive train and consequently designed to drive a motor vehicle, in particular a passenger car.

As part of the operating method, the ignition injection is carried out during a partially stratified combustion process (HOS), wherein for example by means of the valve means, the second ejection opening is released, while the first ejection opening is fluidly blocked by the valve means. As a result, a particularly favorable combustion in the combustion chamber can be realized. By means of the injector, it is thus possible to inject the first amount and the second amount of the fuel at different times and to use for different purposes, for example, the first ejection opening is used to implement a so-called main injection, and wherein the second ejection opening, for example, to realize a Ignition injection, in particular in a stratified charge combustion method and especially in a partial stratified charge combustion method is used.

The first ejection opening is formed, for example, as an annular gap and thus at least substantially annular, so that, for example, an annularly arranged conical nozzle is realized. As a result, a particularly large first quantity of the fuel can be injected into the combustion chamber, thereby realizing a main injection for mixture formation.

Furthermore, by means of the injector according to the invention a particularly good smoothness of the internal combustion engine can be realized. This follows from a particularly advantageous atomization of the fuel and thus the better flammability of the ignition injection by the preferably very small-dimensioned second ejection opening for the ignition injection.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 a schematic sectional view of an internal combustion engine, in particular a motor vehicle, with at least one injector for injecting fuel directly into a combustion chamber of the internal combustion engine, wherein the injector has at least a first ejection opening and at least one second ejection opening for direct injection of the fuel and a valve device formed thereto is to release the ejection orifices at different times;

2 a schematic perspective view of the injector in sections; and

3 a detail of another schematic perspective view of the injector.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

1 shows a schematic sectional view of an internal combustion engine, which is designed as a reciprocating piston engine, in particular as a reciprocating internal combustion engine. The internal combustion engine is for example part of a drive train of a motor vehicle, in particular a passenger car, wherein the motor vehicle is drivable by means of the internal combustion engine. The internal combustion engine comprises at least one combustion chamber in the form of a cylinder 10 in which a piston 12 is recorded translationally movable. The piston 12 For example, is connected via a connecting rod articulated to an output shaft of the internal combustion engine, wherein the output shaft is rotatably mounted on a housing member of the internal combustion engine about an axis of rotation relative to the housing member. As a result of the articulated coupling, the translational movements of the piston 12 in the cylinder 10 be converted into a rotational movement of the output shaft. The output shaft is designed, for example, as a crankshaft, the internal combustion engine providing torques for driving the motor vehicle via the output shaft.

The cylinder 10 is in this case exactly one injector 14 assigned to the internal combustion engine. The injector 14 is also referred to as an injection nozzle or injection valve, wherein by means of the injector 14 Fuel, especially liquid fuel, in the cylinder 10 injected directly. This means that the injector 14 for injecting the liquid fuel directly into the cylinder 10 is trained. As part of the injector 14 Injected injection of the fuel forms at least one fuel jet, wherein in 1 a first fuel jet 16 and a second fuel jet 18 are shown.

The cylinder 10 is at least one in 1 particularly schematically illustrated ignition device 20 assigned. The cylinder 10 Both fuel and air are supplied, so in the cylinder 10 a fuel-air mixture is created. The fuel becomes the cylinder 10 fed so that the fuel by means of the injector 14 in particular with formation of at least one of the fuel jets 16 and 18 injected directly.

The fuel-air mixture is ignited and thereby burned. To ignite the fuel-air mixture is by means of the ignition device 20 at an ignition point or in an ignition region 22 generates at least one spark, ignited by means of which the fuel-air mixture and thereby burned. One from the ignition area 22 different area of the cylinder 10 is in 1 denoted by A.

In synopsis with 2 and 3 it can be seen that the injector 14 a first ejection opening 24 and a second ejection opening 26 having, wherein the second ejection opening 26 from the first ejection opening 24 is spaced. The ejection openings 24 and 26 are also referred to as injection openings, ejection openings or injection holes and are formed for example as passage openings. On the one hand are the ejection openings 24 and 26 For example, fluidly connected to a receiving space, wherein the receiving space in the injector 14 is arranged. For example, the injector includes 14 at least one housing 28 in which the receiving space for receiving the fuel is arranged. Because the ejection opening 24 respectively 26 is fluidly connected to the receiving space, located in the receiving space fuel in the ejection opening 24 respectively 26 stream. On the other hand, the respective ejection openings open 24 and 26 to the environment of the injector 14 , The fuel becomes the injector 14 , in particular the receiving space, for example, supplied by a fuel distribution element, which is also referred to as a rail.

The injector 14 also includes a particularly good 2 and 3 recognizable, as a whole with 30 designated valve means for releasing and closing the ejection openings 24 and 26 , Gives the valve device 30 the ejection openings 24 and 26 free, so the fuel can the respective ejection openings 24 and 26 flow through, allowing the fuel from the receiving space through the injection ports 24 and 26 to the environment of the injector 14 can flow, so that the fuel in the combustion chamber (cylinder 10 ) is injected directly. Be the ejection openings 24 and 26 by means of the valve device 30 closed, that is fluidly blocked, so the fuel can the ejection openings 24 . 26 do not flow through.

In order to realize a particularly advantageous and in particular low-emission operation of the internal combustion engine and a very good smoothness of the internal combustion engine, the valve device 30 adapted to the first ejection opening 24 for injecting a first amount of the fuel at a first time and the second ejection opening 26 for injecting a smaller, compared to the first amount, second amount of the fuel at a different from the first time, second time release. The valve device 30 is for example designed to the ejection opening 24 release and at the same time the ejection opening 26 to block fluidly. Alternatively or additionally, it is conceivable that the valve device 30 the ejection openings 26 is released while the ejection opening 24 fluidly blocked.

In the illustrated embodiment, the ejection opening 26 an injection hole for realizing an ignition injection, which comprises the second quantity of the fuel which is lower than the first quantity. Yes, after operation and type of internal combustion engine, an ignition injection of the fuel through the ejection port 26 also include an equal to or even greater amount of fuel than the first amount of injected fuel. If the ignition injection is carried out, the fuel jet is formed 18 out. In synopsis with 1 is thus apparent that the ejection opening 26 on one of the ignition area 22 facing side of the injector 14 is arranged so that the fuel through the ejection opening 26 in the ignition area 22 is injectable.

The first ejection opening 24 and thus the first amount of fuel is used, for example, to realize a so-called mixture injection for mixture formation. Since the first amount is substantially greater than the second amount, the first amount is utilized to provide a sufficient fuel-air mixture in the cylinder 10 to realize. Here is the ejection opening 24 in the present case at least substantially annular, so that the injection jet 16 which is formed when performing the mixture injection, for example, is designed as a cone or beam cone. In the drawing, for better clarity, only part of the jet cone of the injection jet 16 shown, which the ignition area 22 is opposite, so as not in the representation with the staggered fuel injection in the ignition area 22 through the ejection opening 26 to be confusing.

Around the ejection openings 24 and 26 to release at different times, includes the valve means 30 one of the first ejection opening 24 associated, first valve element 32 for releasing and closing the first ejection opening 24 , Furthermore, the valve device comprises one of the second ejection opening 26 associated, second valve element 34 for releasing and closing the second ejection opening 26 , The valve elements 32 and 34 are designed as so-called valve needles, wherein the valve elements 32 and 34 are movable relative to each other. In this case, the first valve element 32 in one by a directional arrow 36 illustrated first direction movable to thereby the first ejection opening 24 release. The second valve element 34 is in one of the first direction opposite, by a directional arrow 38 illustrated second direction movable to thereby the second ejection opening 26 release. The valve elements 32 and 34 are translationally relative to the housing in the respective directions 28 movable.

Out 2 and 3 is particularly well recognizable that the valve element 32 as outward, that is in the direction of the cylinder 10 opening valve needle is formed. This means that the valve element 32 in the direction of the combustion chamber (cylinder 10 ) or in the cylinder 10 moves when the valve element 32 is opened. The valve element 34 however, is designed as an inwardly opening valve needle, since the valve element 34 moved away from the cylinder during opening.

Will the valve element 30 moved in the first direction and thereby opened, so gives the valve element 32 the first ejection opening 24 in the form of an annular gap, thereby realizing the mixture injection. Mixture injection is also referred to as main injection, which is used for mixture formation in the cylinder 10 is used. Will the valve element 34 open, so gives the valve element 34 exactly a single injection hole in the form of ejection opening 26 free to thereby realize the ignition injection.

The advantage of the injector 14 On the one hand there is the significant reduction of emissions by a low, optimally aligned ignition injection quantity and on the other hand in the stable flammability of the mixture and the resulting smoother running of the internal combustion engine. A better atomization and thus better flammability of the ignition injection is achieved by a small dimensionable injection hole or injection holes for the ignition.

In particular, it is provided that the ejection openings 24 and 26 differ in their respective flow cross-section through which the fuel can flow, the flow cross-sections differing in their shape and / or in their size. This makes it possible, for example, with the same injection time by means of the ejection opening 24 a much larger amount of fuel than by means of the ejection opening 26 inject.

LIST OF REFERENCE NUMBERS

10

cylinder

12

piston

14

injector

16

Fuel jet

18

Fuel jet

20

ignition device

22

ignition

24

first ejection opening

26

second ejection opening

28

casing

30

valve means

32

valve element

34

valve element

36

arrow

38

arrow

A

Area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 2656276 A1 [0002]

Claims (8)

Injector ( 14 ) for direct injection of fuel into a combustion chamber ( 10 ) of an internal combustion engine, in particular for a motor vehicle, with at least one first ejection opening ( 24 ) for direct injection of the fuel, with at least one second ejection opening ( 26 ) for direct injection of the fuel, and with a valve device ( 30 ) for releasing and closing the ejection openings ( 24 . 26 ), characterized in that the valve device ( 30 ) is adapted to the first ejection opening ( 34 ) for injecting a first amount of the fuel at a first time and the second ejection opening (FIG. 26 ) for injecting a second quantity of the fuel at a second time different from the first time. Injector ( 14 ) according to claim 1, characterized in that the valve device ( 30 ) one of the first ejection opening ( 24 ), the first valve element ( 32 ) for releasing and closing the first ejection opening ( 24 ) and one of the second ejection opening ( 26 ), second valve element ( 34 ) for releasing and closing the second ejection opening ( 26 ), wherein the valve elements ( 32 . 34 ) are movable relative to each other. Injector ( 14 ) according to claim 2, characterized in that the first valve element ( 32 ) is movable in a first direction to thereby the first ejection opening ( 24 ), wherein the second valve element ( 34 ) is movable in a direction opposite to the first direction, the second direction, thereby the second ejection opening ( 26 ). Injector ( 14 ) according to one of the preceding claims, characterized in that the ejection openings ( 24 . 26 ) differ in their respective flow cross section through which the fuel can flow. Injector ( 14 ) according to claim 4, characterized in that the flow cross-sections differ in their shape and / or their size from each other. Injector ( 14 ) according to one of the preceding claims, characterized in that the second ejection opening ( 26 ) to an ignition region ( 22 ), in which a fuel-air mixture in the combustion chamber ( 10 ) is to be ignited is aligned. Injector ( 14 ) according to claim 6, characterized in that the first ejection opening ( 24 ) on a firing range ( 22 ) facing away from the injector ( 14 ) is arranged. Injector ( 14 ) according to one of the preceding claims, characterized in that the second quantity of the fuel, which flows through the second ejection opening ( 26 ) is less than the first amount of fuel, which through the first ejection opening ( 34 ) is injectable.

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