DE102018003529A1 - Iniektoranordnung an injector of an internal combustion engine - Google Patents

Abstract

The invention relates to an injector arrangement (10) of an injector (40) on a cylinder head (20) of an internal combustion engine, in which an injector end (42) of the injector projects into a combustion chamber (30) of the internal combustion engine. Via injection bores (50, 52, 54, 56, 58, 60) distributed regularly over a circumference (44) of the injector end, fuel (12) can be injected directly into the combustion chamber. Fuel injectors (70, 72, 74, 76, 78, 80) injectable via the injection bores into the combustion chamber via the injection bores close a first injection angle (β) with a cylinder center axis (22) and at an outlet side, piston near first chamber region (32) of the combustion chamber at an inlet side, close to the piston second chamber portion (34) of the combustion chamber a larger compared to the first spray angle, the second spray angle (α) with the cylinder center axis. In this case, an injector center axis (46) of the injector encloses an alignment angle (γ) with the cylinder center axis, so that the first injection angle (β) is thereby smaller than the second injection angle (α).

Description

The invention relates to an injector arrangement of an injector of an internal combustion engine, according to the preamble of patent claim 1.

In gasoline engines with internal mixture formation (direct injection), in a so-called homogeneous operation, the best possible distribution of fuel injected into a combustion chamber of the gasoline engine can enable efficient and low-emission combustion. Wetting respective combustion chamber walls (cylinder wall, piston wall, combustion chamber roof) and respective intake valves with liquid fuel leads to increased pollutant emissions and should therefore be avoided as far as possible. An interaction of respective fuel jets in the form of fuel sprays with an in-cylinder flow is significant.

Especially supercharged engines (internal combustion engines with turbocharger or compressor) usually have a higher or stronger charge movement (also called tumble flow) compared to engines without charging on. Due to the higher charge movement, there is a particularly strong influence and movement of the fuel spray injected in the combustion chamber (combustion chamber). In engines (internal combustion engines) with a central position of an injector, the injected fuel is directed by the charge movement to an outlet side, in other words on one side of the cylinder or the combustion chamber on which respective exhaust valves are located, whereby there increased fuel concentrations can arise and there can come to an undesirable wall wetting. The wetting of the wall (wetting of respective combustion chamber walls) leads to increased fuel input into the engine oil of the internal combustion engine, in other words to a so-called engine oil dilution. Especially with small displacement engines is a favorable design or arrangement of injectors, which can also be referred to as injectors, difficult, so that the prevention of wetting the combustion chamber walls with fuel is a particular challenge.

Injectors, which can be designed as injection valves with multi-hole nozzles, are widely used in gasoline engines designed as internal combustion engines with direct injection. Usual are five to seven injection holes, which can also be referred to as injection holes. In order to achieve a good atomization of the fuel is often injected with injection pressures in the range of 20 MPa or 35 MPa. The injector is often arranged either laterally between respective inlet channels or in such a way that an injector end is arranged at the level of a combustion chamber center, that is to say in the region of a cylinder center axis (so-called lateral injector layer or central injector layer). The injection holes are usually arranged in a circle and often have an identical spray hole geometry.

From the DE 10 2012 018 780 A1 For example, an injector is known which injects a smaller amount of fuel toward respective exhaust valves than toward respective intake valves. An injection hole for an inlet side in this case has a first opening diameter which is greater than a second opening diameter of an injection hole for an outlet side.

The DE 10 2009 046 001 A1 describes a fuel injector for an internal combustion engine having a needle, a housing, a fuel inflow passage and a plurality of intermediate flow passages. The intermediate flow passages include a first intermediate flow passage, with which a first injection nozzle hole of the housing forms a first flow passage structure, and a second intermediate flow passage, with which a second injection nozzle hole of the housing forms a second flow passage structure. The first flow channel structure has a larger flow channel resistance than the second flow channel structure.

Object of the present invention is to provide an injector of the type mentioned, by which a wetting of combustion chamber walls can be reduced with fuel.

This object is achieved by an injector arrangement having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are the subject of the dependent claims.

The invention is based on an injector arrangement of an injector of an internal combustion engine, in particular of a gasoline engine, on a cylinder head of the internal combustion engine. In the injector arrangement, an injector end of the injector held centrally on the cylinder head protrudes, at least in regions, into a combustion chamber of the internal combustion engine which is limited by the cylinder head, by a cylinder wall and by a movable piston of the internal combustion engine. In addition, in the injector arrangement, the injector has a plurality of injection bores distributed at least substantially regularly over a circumference of the injector end, via which fuel can be injected directly into the combustion chamber. In the injector assembly injectable fuel jets via the plurality of injection holes in the combustion chamber by means of the injector an outlet-side, near the piston first chamber portion of the combustion chamber, a first injection angle with a cylinder center axis, and at an inlet side, close to the piston second chamber portion of the combustion chamber a larger compared to the first spray angle, second spray angle with the cylinder center axis.

By the expression that the injector is held "centered" on the cylinder head, it is to be understood that the cylinder center axis may pass through the injector or at least through the injector end projecting into the combustion chamber.

By expressing that the plurality of injection bores are "at least substantially regularly distributed around the circumference of the injector end", it should be understood that the respective injection bores may be arranged, for example, in a regular pattern. This allows a particularly uniform fuel injection into the combustion chamber. The term "close to the piston" is to be understood as meaning that the first spraying angle and the second spraying angle are open in the direction of the piston, in other words in the vicinity of the piston. The first spraying angle and the second spraying angle are defined, as it were, by a center axis section of the cylinder center axis extending between the injector end and the piston.

In order to effectively reduce the wetting of combustion chamber walls with fuel, it is provided according to the invention that an injector center axis of the injector includes an orientation angle with the cylinder center axis, thereby making the first injection angle smaller than the second injection angle. This is advantageous because a central injector layer is provided by the central holding of the injector on the cylinder head and, given the different injection angles, a particularly favorable fuel distribution in the combustion chamber is provided. Due to the fact that the first spray angle is smaller than the second spray angle, a steeper injection of fuel into the combustion chamber is possible on the outlet side (exhaust valve side) than on the inlet side (intake valve side). In other words, the fuel jets, which can also be referred to as injection jets, close on the outlet side, ie in the region of respective exhaust valves of the internal combustion engine, the first spray angle with the cylinder center axis and inlet side, ie in the region of respective intake valves of the internal combustion engine, the larger second spray angle with the cylinder center axis which is enabled by the injector axis including the orientation angle with the cylinder center axis, in other words, the injector is inclined relative to the cylinder center axis.

The invention is based on the finding that a proportion of fuel injected on the outlet side is detected and moved much more strongly as a result of charge movement in the combustion chamber than, for example, a fuel portion injected on the inlet side, which is injected through other (intake-side) injection ports. As a result, the fuel injected on the outlet side (in the direction of the outlet side) can lead to burning-wall wetting more quickly and in greater quantity, for example touching or reaching the cylinder wall or the piston and leading there to undesired effects, such as engine oil dilution. By virtue of the present injector arrangement, the combustion chamber wall wetting can be completely prevented or at least substantially reduced or reduced.

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 in the figures alone 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.

• 1 eine schematische Unteransicht einer Injektoranordnung eines Injektors einer Verbrennungskraftmaschine; und
• 2 eine Seitenansicht der Injektoranordnung.

Showing:

• 1 a schematic bottom view of an injector of an injector of an internal combustion engine; and
• 2 a side view of the injector.

1 and 2 each show different views of an injector 10 an injector 40 an in this case only partially shown internal combustion engine, which is designed as a gasoline engine.

The injector 40 is on a cylinder head 20 the internal combustion engine arranged centrally, with an injector 42 the center of the cylinder head 20 held injector 40 partially into a through the cylinder head 20 , through a cylinder wall of a cylinder 24 and by a movable piston 26 the internal combustion engine limited combustion chamber 30 the internal combustion engine protrudes.

In 1 and 2 is one on the cylinder 24 indicated coordinate system, which by a first radial extension direction x , through a second radial extension direction y and by a longitudinal direction z (in which also a stroke of the piston 26 done) are defined.

The injector 40 has a plurality of regularly over a circumference 44 of the injector end 42 distributed injection holes 50 . 52 . 54 . 56 . 58 . 60 on what fuel 12 directly into the combustion chamber 30 injectable, in particular in 1 is shown.

From the synopsis of 1 and 2 it can be seen that by means of the injector 40 over the majority of injection holes 50 . 52 . 54 . 56 . 58 . 60 into the combustion chamber 30 injectable fuel jets 70 . 72 . 74 . 76 . 78 . 80 at an outlet side, near the piston first chamber area 32 the combustion chamber 30 a first spray angle β with a cylinder center axis 22 lock in. Furthermore, from the synopsis of 1 and 2 recognizable that over the majority of injection holes 50 . 52 . 54 . 56 . 58 . 60 60 into the combustion chamber 30 injectable fuel jets 70 . 72 . 74 . 76 . 78 . 80 at an inlet side, near the piston second chamber area 34 the combustion chamber 30 one compared to the first spray angle β larger, second spray angle α with the cylinder center axis 22 lock in.

An injector center axis 46 of the injector 40 closes an alignment angle γ with the cylinder center axis 22 a, so that thereby the first spray angle β in this case is smaller by an angle of 8 °, than the second spray angle α , This allows a particularly favorable fuel distribution while at least largely avoiding wetting of combustion chamber walls with fuel.

The cylinder center axis 22 is present along the longitudinal direction z oriented. The orientation angle γ in the present case extends in one through the first radial extension direction x as well as through the longitudinal direction z spanned level, which can also be referred to as xz-level. Accordingly, the injector center axis 46 of the injector 40 in the xz plane, so to speak, with respect to the cylinder centerline 22 around the orientation angle γ inclined.

1 shows that the cylinder head 20 a so-called combustion chamber roof forms, which the combustion chamber 30 towards the top, in other words against the direction of longitudinal extension z concludes. On the cylinder head 20 are respective intake valves 13 . 14 and respective exhaust valves 15 . 16 movably received. In the present case, the two intake valves 13 . 14 as well as the two exhaust valves 15 . 16 each symmetrical to the first radial extension direction x arranged. In other words, the axis of the first radial extension direction runs x between the two inlet valves 13 . 14 as well as the two exhaust valves 15 . 16 as symmetry axis.

Furthermore, on the cylinder head 20 or on the combustion chamber roof an ignition source 17 , which may be configured for example as a spark plug, added to a mixture of the fuel 12 and to ignite air, causing a combustion of the fuel 12 and an associated movement of the piston 26 along the longitudinal direction z is effected. The intake valves 13 . 14 and the exhaust valves 15 . 16 in their respective closed position to a piston distant, third chamber area 36 as from the synopsis of 1 and 2 is recognizable, or protrude into their respective open position in the third chamber area 36 , which is not shown here. The exhaust valves 15 . 16 are the first chamber area 32 and the intake valves 13 . 14 the second chamber area 34 assigned.

The injector 40 In the present case, it is designed to be in the outlet-side, piston-near first chamber region 32 to inject a smaller amount of fuel, as in the inlet side, close to the piston second chamber area 34 , Accordingly, for example, via the fuel jets 72 . 74 (second fuel jet 72 , third fuel jet 74 ) For example, fuel quantities of fuel 12 of 9% each, in a single injection operation by means of the injector 40 injected fuel total in the outlet side, first chamber area 32 the combustion chamber 30 be introduced. About the fuel jets 78 . 80 (fifth fuel jet 78 , sixth fuel jet 80 In contrast, for example, in each case fuel proportions of 21% of the total fuel amount in the inlet-side, second chamber area 34 be introduced. About the fuel jets 70 . 76 (first fuel jet 70 fourth fuel jet 76 ) can each be introduced fuel shares of 20%. This division of the fuel components allows surprisingly a particularly favorable fuel distribution in the combustion chamber 30 ,

Characterized in that the injector is adapted to, in the outlet side, close to the piston first chamber area 32 to inject the total smaller amount of fuel, as in the inlet side, close to the piston second chamber area 34 , An undesirable Motorölverdünnung can be counteracted in a particularly favorable manner.

At least two adjacent fuel jets of the plurality of fuel jets 70 . 72 . 74 . 76 . 78 . 80 can in their projection on one, to the injector center axis 46 vertical projection plane having a central axis angle which is less than or equal to 80 °, whereby a particularly favorable fuel distribution of the fuel 12 in the combustion chamber 30 is achieved. The projection plane in this case runs parallel to one through the first radial extension direction x and the second radial extension direction y spanned level, which can also be referred to as xy plane. In other words, close the respective injection holes 50 . 52 . 54 . 56 . 58 . 60 associated Bohrungsmittelachsen 90 . 92 . 94 . 96 . 98 . 100 at least partially in the projection on the projection plane, the central axis angle of less than or equal to 80 ° with each other.

The present injector arrangement 10 reduces wall wetting, improves mixture formation and thus reduces fuel consumption while reducing CO ₂ emissions. Furthermore, the injector assembly carries 10 to reduce hydrocarbon emissions (HC emissions) and particulate emissions. In addition, the Motorölverdünnung can be significantly reduced and a starting behavior of the internal combustion engine can be improved. A respective, also known as the injection hole length, bore length of the respective injection holes 50 . 52 . 54 . 56 . 58 . 60 of 200 microns has proved to be particularly advantageous. In addition, injection pressures of more than 20 MPa, preferably 35 MPa have proven to be advantageous. The orientation angle γ and thus the inclination of the injector 40 opposite the central axis 22 is preferably a maximum of 20 °. The injection holes 50 . 52 . 54 . 56 . 58 . 60 preferably have a respective diameter (spray hole diameter) in the range of 100 to 250 microns. The injector 40 is preferably designed such that an injection quantity at an injection pressure of 100 bar in the range of 300 g / min to 600 g / min. A nozzle needle of the injector 40 is preferably actuated electromagnetically.

LIST OF REFERENCE NUMBERS

10

injector

12

fuel

13

intake valve

14

intake valve

15

outlet valve

16

outlet valve

17

ignition source

20

cylinder head

22

Cylinder center axis

24

cylinder

26

piston

30

combustion chamber

32

first chamber area

34

second chamber area

36

third chamber area

40

injector

42

injector end

44

scope

46

Injektormittelachse

50

first injection hole

52

second injection hole

54

third injection hole

56

fourth injection hole

58

fifth injection hole

60

sixth injection hole

70

first fuel jet

72

second fuel jet

74

third fuel jet

76

fourth fuel jet

78

fifth fuel jet

80

sixth fuel jet

90

first bore center axis

92

second bore center axis

94

third bore center axis

96

fourth bore center axis

98

fifth bore center axis

100

sixth bore center axis

x

first radial extension direction

y

second radial extension direction

z

Longitudinal extension

β

first angle

α

second angle

γ

alignment angle

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 102012018780 A1 [0005]
• DE 102009046001 A1 [0006]

Claims (4)

Injector assembly (10) of an injector (40) of an internal combustion engine, in particular a gasoline engine, on a cylinder head (20) of the internal combustion engine, wherein an injector (42) of the center of the cylinder head (20) held injector (40) at least partially into a through the cylinder head (20), by a cylinder wall and by a movable piston (26) of the internal combustion engine limited combustion chamber (30) of the internal combustion engine protrudes, wherein the injector (40) has a plurality of at least substantially regularly over a circumference (44) of the injector (42) distributed injection bores (50, 52, 54, 56, 58, 60), via which fuel (12) can be injected directly into the combustion chamber (30), and in which by means of the injector (40) over the plurality of Injection bores (50, 52, 54, 56, 58, 60) injectable into the combustion chamber fuel jets (70, 72, 74, 76, 78, 80) on an outlet side, close to the piston first Kamme The combustion chamber (30) has a first injection angle (β) with a cylinder center axis (22) and an inlet-side, piston-near second chamber region (34) of the combustion chamber (30) which is larger in comparison to the first injection angle (β) , second injection angle (α) with the cylinder center axis (22), characterized in that an injector center axis (46) of the injector (40) includes an orientation angle (γ) with the cylinder center axis (22) thereby making the first injection angle (β) smaller is, as the second spray angle (α). Injector assembly (10) according to Claim 1 , characterized in that the first spraying angle (β) is smaller by an angular amount of at least 8 °, than the second spraying angle (α). Injector assembly (10) according to Claim 1 or 2 , characterized in that the injector (40) is adapted to inject a smaller amount of fuel into the outlet side, near the piston first chamber portion (32), as in the inlet side, close to the piston second chamber portion (34). Injector assembly (10) according to Claim 1 or 2 characterized in that at least two adjacent fuel jets of the plurality of fuel jets (70, 72, 74, 76, 78, 80) projected on a projection plane perpendicular to the injector center axis (46) have a central axis angle which is less than or equal to 80 ° ,

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