CN109281756B

CN109281756B - Internal combustion engine and method for operating an internal combustion engine

Info

Publication number: CN109281756B
Application number: CN201810782252.2A
Authority: CN
Inventors: S.凯尔纳; A.赫鲁嫩代克; E.波特
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2017-07-19
Filing date: 2018-07-17
Publication date: 2021-03-30
Anticipated expiration: 2038-07-17
Also published as: CN109281756A; DE102017116244A1

Abstract

The invention relates to an internal combustion engine for driving a motor vehicle. An internal combustion engine has an engine block and a cylinder head connected to the engine block. In internal combustion engines, combustion chambers are formed in which pistons connected to a crankshaft via connecting rods are movable and compress an air mixture for combustion. At least one fuel injector having a fuel nozzle is arranged on the cylinder head, by means of which fuel can be injected into a combustion chamber of the internal combustion engine. The fuel nozzle has a plurality of nozzle openings, which are arranged on a first bore pitch circle and a second bore pitch circle of the fuel nozzle. The invention also relates to a method for operating such an internal combustion engine, in a first operating state the internal combustion engine is operated at a low load with a high compression ratio and fuel is injected into the combustion chamber only through the outlet openings in the first hole pitch circle of the fuel injector, and in a second operating state the internal combustion engine is operated at a high load with a low compression ratio and fuel is injected into the combustion chamber through the outlet openings in the two hole pitch circles.

Description

Internal combustion engine and method for operating an internal combustion engine

Technical Field

The present invention relates to an internal combustion engine and a method for operating an internal combustion engine.

Background

The compression ratio of modern internal combustion engines, in particular direct fuel injection diesel engines, has a decisive influence on the efficiency of the internal combustion engine and also on the emissions. Furthermore, the cold start performance and the heating of the exhaust gas aftertreatment component depend on the compression ratio of the internal combustion engine. The compression ratio in internal combustion engines with constant compression ratios known from the prior art is therefore always a compromise between different requirements.

Furthermore, internal combustion engines with variable compression ratios are known, in which the compression ratio can be adapted to the operating state of the internal combustion engine. From WO 2016/016194 a1 an internal combustion engine with a variable compression ratio is known, in which the connecting rod length is adjusted accordingly in order to change the compression ratio, so that the piston is spaced at the top dead center from the combustion chamber boundary at the cylinder head according to the desired compression ratio. Furthermore, WO 2016/016194 a1 also relates to a method for operating an internal combustion engine, in which an adjustable compression ratio can be changed at least during operation of the internal combustion engine, and additionally at least one further engine component is coordinated with the change in the compression ratio.

A disadvantage of the known method is, however, that adjusting the compression ratio alone does not place the engine in optimal operating conditions.

Disclosure of Invention

The object of the invention is to improve the cold start capability of an internal combustion engine and at the same time increase the thermodynamic efficiency and reduce emissions.

The object is achieved according to the invention by an internal combustion engine having an engine block and a cylinder head, wherein the internal combustion engine comprises at least one combustion chamber, in which a piston for compressing an air mixture for combustion is arranged. In this case, at least one fuel injection valve, preferably a fuel injector of a high-pressure injection system, which comprises a fuel injection nozzle, is arranged in the cylinder head. The internal combustion engine has a variable compression ratio which can be varied during operation of the internal combustion engine. The fuel nozzle has a plurality of nozzle orifices arranged on two different pitch circles. The combination of the variable compression ratio of the internal combustion engine with the different nozzle openings on the plurality of pitch circles makes it possible to meet the increasing demands for low-emission, maximum-efficiency engine operation and to overcome the disadvantages known from the prior art.

In a preferred embodiment of the invention, it is provided that the outlet openings of the first hole pitch circle have a flatter spray angle than the outlet openings of the second hole pitch circle. The arrangement of the nozzles is preferably selected such that the beam cone of the second hole pitch circle is located between the beam cones of the first hole pitch circle. This means that, viewed from below or from above, the nozzle openings of the second hole pitch circle deviate from the angle bisector between two adjacent nozzle openings of the first hole pitch circle by an angle of less than 20 °, and are particularly preferably arranged symmetrically to this angle bisector. By means of the flat injection angle, a small injection quantity can be introduced into the combustion recess of the piston in a targeted manner, so that the introduced fuel does not hit low-temperature combustion chamber walls or the piston, or only in small quantities. Hereby, an efficient conversion of the fuel can be achieved, while emissions are low.

In a further development of the internal combustion engine, it is provided that the outlet opening of the first bore pitch circle has a smaller diameter than the outlet opening of the second bore pitch circle. In this case, the injection quantity can be adjusted accordingly when the load increases, so that a higher power value can be achieved for a smaller atomization quantity as with the introduction of a larger fuel.

In an advantageous embodiment of the invention, it is provided that the number of outlet openings on the first hole pitch circle is greater than the number of outlet openings on the second hole pitch circle. In this case, the first pitch circle preferably has at least three, particularly preferably four, outlet openings which are distributed uniformly in the circumferential direction of the fuel nozzle, while the second pitch circle preferably has at least one outlet opening, particularly preferably exactly two outlet openings which are smaller than the first pitch circle and which are preferably spaced apart from one another by 180 ° in the circumferential direction of the fuel nozzle. The total throughflow of the injection openings of the second hole pitch circle is in this case 50% to 400%, particularly preferably in the range of 70% to 200%, of the total throughflow of the injection openings of the first hole pitch circle. Good atomization and uniform distribution of the fuel in the combustion chamber can be achieved by a relatively large number of smaller nozzles on the first orifice pitch circle, whereby the tendency for soot formation can be reduced.

In a preferred embodiment of the invention, it is provided that the section of the fuel nozzle facing the combustion chamber of the internal combustion engine is conical in shape, so that the first bore pitch circle has a smaller diameter than the second bore pitch circle. In this case, at least one of the bore pitch circles, preferably both bore pitch circles, are located in the conical section of the fuel nozzle. Alternatively, one of the two bore pitch circles may also be formed in the cylindrical section of the fuel nozzle. Since the conical section can implement a relatively wide range of possible spray angles in a relatively simple manner, a steeper spray angle can be implemented than if the spray openings were arranged in a cylindrical region, which is advantageous in particular for the spray openings on the second pitch circle.

In an advantageous development of the invention, it is provided that the injection angle of the nozzles of the first bore pitch circle is between 155 ° and 175 °, and the injection angle of the second bore pitch circle is between 90 ° and 170 °. It is particularly advantageous here if the spray angle of the outlet openings of the first hole pitch circle is at least 5 ° greater than the spray angle of the outlet openings of the second hole pitch circle. If the second hole-pitch nozzle orifice has a steeper spray angle than the first hole-pitch nozzle orifice, the fuel metered through the second hole-pitch nozzle orifice also reaches the combustion recess of the piston, so that the fuel can be optimally displaced.

The internal combustion engine is preferably designed as a self-igniting internal combustion engine according to the diesel principle and has no additional ignition mechanism for the external ignition of the combustion mixture in the combustion chamber of the internal combustion engine.

The compression ratio of the internal combustion engine is preferably between 13 and 23, wherein the compression ratio can be varied steplessly or in two or more specific steps. Here, the difference between the minimum compression ratio and the maximum compression ratio is preferably 2 to 8 units. The difference between the minimum and maximum compression ratio is preferably 2.5 to 6 units, particularly preferably 3 to 4 units. Both a stepless adjustment of the compression ratio and a three-point or two-point adjustment are conceivable, which can be implemented more technically simply. With a variable compression ratio of between 13 and 23, in particular between 14 and 20, different operating states can be adapted, wherein a cold start capability can be improved, the exhaust gas aftertreatment component can be heated up in an accelerated manner, and a maximally efficient normal operation of the internal combustion engine can be achieved.

In a preferred embodiment of the invention, it is provided that the compression ratio is between 17 and 23 in a first level with a higher degree of compression and between 13 and 17 in a second level with a lower degree of compression.

In a preferred embodiment of the invention, it is provided that the internal combustion engine is operated in a first operating state, in particular at low loads, with a high compression ratio, wherein fuel is injected into the combustion chamber only through the first hole-pitch circle nozzle openings. The combination of a high compression ratio and a small injection quantity metered only through the first bore-pitch nozzle opening can improve the operating behavior of the internal combustion engine, in particular during the cold start phase of the internal combustion engine.

In an advantageous embodiment, it is provided that the internal combustion engine is operated in a second operating state, in particular at high load, at a low compression ratio, wherein fuel is injected both through the first and through the second port opening. The engine can achieve higher efficiency during normal operation due to injection through two orifice pitch circles and a reduced compression ratio.

In an advantageous development of the internal combustion engine, it is provided that the compression ratio can be varied by varying the effective connecting rod length of the connecting rod connected to the piston. The compression ratio of the engine can be adjusted by changing the effective connecting rod length in order to obtain the aforementioned advantages.

In a further refinement of the invention, it is provided that the piston has a combustion recess on its end face facing the fuel nozzle. The combustion of the fuel-air mixture in the combustion chamber can be facilitated by the combustion recess, wherein the fuel injected into the combustion chamber can be optimally mixed with the air supplied via the intake valve.

According to the invention, a method for operating an internal combustion engine having an engine block and a cylinder head is proposed, wherein the internal combustion engine comprises at least one combustion chamber, preferably at least three combustion chambers. In the combustion chamber, a piston connected to a crankshaft via a connecting rod is movable, by means of which piston a combustion mixture in the combustion chamber of the internal combustion engine can be compressed. At least one fuel injection valve is disposed in the cylinder head, the fuel injection valve including a fuel injection nozzle. The compression ratio of the internal combustion engine can be varied here, in particular by varying the effective connecting rod length. The fuel nozzle has a plurality of nozzle openings distributed over a first and a second hole pitch circle in the circumferential direction of the fuel nozzle. In a first operating state, the internal combustion engine is operated at a low load with a high compression ratio of 17 to 23, wherein in this operating state fuel is injected into the combustion chamber only through the first hole pitch circle nozzle openings. In addition, in a second operating state, the internal combustion engine is operated at a high load with a low compression ratio of 13 to 17, wherein fuel is injected into at least one combustion chamber of the internal combustion engine via two orifice pitch circles. By means of the method according to the invention, the exhaust gas aftertreatment component can be brought to its operating temperature more quickly after a cold start, and the cold startability of the internal combustion engine can be improved generally, and the efficiency of the internal combustion engine can be improved in normal operation, since the compression ratio is no longer designed as a compromise between different requirements, but can be adapted to a plurality of operating situations in each case.

In a further development of the method, it is provided that the internal combustion engine is operated at a high compression ratio at a relatively low temperature in the exhaust gas duct of the internal combustion engine, in particular at a temperature of less than 250 ℃, particularly preferably at a temperature of less than 150 ℃, in order to improve the cold start phase of the internal combustion engine and to facilitate the heating of the exhaust gas aftertreatment component, and that the internal combustion engine is operated at a relatively high temperature, in particular at a temperature of more than 350 ℃, at a low compression ratio. In this way, the smoothness of operation of the internal combustion engine and the reduction of nitrogen oxide emissions can be improved in phases in which no additional heating of components of the exhaust gas aftertreatment device in the exhaust gas system is required. In this way, the heating of the exhaust gas aftertreatment component can be further improved at lower temperatures in the exhaust gas duct, and, if necessary, high compression ratios can be dispensed with in the region of the characteristic curve at higher temperatures in the exhaust gas duct, as a result of which the efficiency of the internal combustion engine can be increased.

The different embodiments of the invention mentioned in the text of this application can combine advantages with one another if they are implemented identically in a single case.

Drawings

The invention is illustrated in the following examples in connection with the accompanying drawings. In this case, identical components or components having the same function are denoted by the same reference numerals in the different figures. In the drawings:

FIG. 1 schematically illustrates an internal combustion engine having a modifiable compression ratio and a fuel injector having a plurality of orifice circles, in accordance with the present disclosure;

FIG. 2 illustrates a fuel nozzle for an internal combustion engine in accordance with the present invention, wherein a plurality of nozzle orifices are distributed over two orifice pitch circles;

FIG. 3 schematically illustrates a first operating condition of the internal combustion engine, wherein the internal combustion engine is operating at a higher compression ratio at a lower part load and the nozzle needle is only opened to an extent until fuel is introduced into the combustion chamber only through the first orifice pitch circle;

fig. 4 schematically shows a second operating state of the internal combustion engine, in which the internal combustion engine is operated at a higher partial or full load with a lower compression ratio and the nozzle needle of the fuel nozzle is opened to such an extent that fuel can be introduced into the combustion chamber both through the first and through the second hole-pitch nozzle openings.

Detailed Description

Fig. 1 schematically shows an internal combustion engine 10 according to the invention. The internal combustion engine 10 has an engine block 12 and a cylinder head 14 connected to the engine block 12, wherein a piston 18 is arranged in a cylinder bore of the engine block 12, and the piston 18 is connected to a crankshaft 58 via a connecting rod 34. The cylinder bore represents the cylinder wall 38, and the piston 18 is guided on the cylinder wall 38 by means of piston rings in a known manner. The piston 18 and the cylinder head 14 define the boundaries of a combustion chamber 16 of the internal combustion engine 10. Furthermore, an intake channel and an exhaust channel for gas exchange of the combustion chamber 16 are formed in the cylinder head 14, wherein the respective channel can be closed by an intake valve 40 or an exhaust valve 42, so that the flow into or out of the combustion chamber 16 is temporarily interrupted. In order to open the intake valve 40, an intake camshaft 54 is provided, and a cam of the intake camshaft 54 presses the intake valve 40 in the direction of the combustion chamber 16, so that the intake valve 40 is opened. For actuating the exhaust valve 42, an exhaust camshaft 56 is provided, wherein cams of the exhaust camshaft 56 control the opening and closing of the exhaust valve 42. In addition, bores are formed in the cylinder head 14 for accommodating fuel injection valves 36, in particular fuel injectors of a high-pressure injection system, in which bores the fuel injection valves 36 are accommodated. The fuel injection valve 36 has a fuel nozzle 20 at its end facing the combustion chamber 16, a plurality of

nozzle openings

22, 24 being formed in the fuel nozzle 20. The

outlet openings

22, 24 are distributed here on a first hole pitch circle 26 and a second hole pitch circle 28, wherein the outlet opening 22 is arranged on the first hole pitch circle 26 and the outlet opening 24 is arranged on the second hole pitch circle 28. The outlet openings 22 of the first bore pitch circle 26 form a first spray cone which has a cone angle α of 155 ° to 175 °, andthe nozzle orifice 24 of the second orifice pitch circle 28 has a second spray cone having a cone angle β of 90 ° to 170 °, wherein the cone angle α of the first spray cone is at least 5 ° greater than the cone angle β of the second spray cone. The piston 18 has a combustion recess 32 on an end face 30 facing the fuel nozzle 20, wherein at least the injection cone of the nozzle openings 22 is directed at the combustion recess 32 when the piston is in a position near top dead center. The effective link length l of the link 34 can be varied in a known manner_PAnd therefore the spacing of the piston 18 relative to the cylinder head 14 near top dead center can be varied, whereby the compression ratio of the internal combustion engine 10 according to the invention is variable.

Fig. 2 shows an enlarged view of a fuel injector 20 of the internal combustion engine 10 according to the invention. The fuel injector 20 has an injector body 44 and an injector needle 46, the injector needle 46 acting as a closing element and resting against the injector body 44 in a valve seat 48. A first group of outlet openings 22, in particular spray openings, is formed in the nozzle body 44, the first group of outlet openings 22 having a diameter D₁And is disposed on the first hole pitch circle 26 of the fuel nozzle 20. Furthermore, a second group of outlet openings 24 is formed in the nozzle body 44, the second group of outlet openings 24 being arranged on the second hole pitch circle 28 and having a diameter D₂. The first bore pitch circle 26 and the second bore pitch circle 28 are formed in the conical section 52 of the nozzle body 44 such that the first bore pitch circle 26 has a smaller diameter D than the second bore pitch circle 28₃The second hole pitch circle 28 has a larger diameter D₄. In this case, the cone angle β of the nozzle openings 24 of the second hole pitch circle 28 is smaller, so that the injected fuel penetrates deeper into the combustion chamber 16. The cone angle α of the nozzle orifice 22 of the first orifice pitch circle 26 is flatter to enable fuel to be introduced into the combustion pocket 32 of the piston 18, particularly near top dead center, and not to hit the relatively cooler cylinder wall 38. In addition, the fuel nozzle 20 also has a nozzle tip 50, the nozzle tip 50 facing the combustion chamber 16. The number of orifices 24 on the second orifice pitch circle 28 is preferably 50% of the number of orifices 24 on the first orifice pitch circle 26. The throughflow of the second hole pitch circle is preferably between 50% and 400%, particularly preferably between 70% and 200%, of the first hole pitch circle, the outlet openings 24 of the second hole pitch circle 28 having a larger diameter D than the outlet openings 22 of the first hole pitch circle 26₂. The arrangement of the nozzles 24 of the second hole pitch circle 28 is preferably selected such thatThe spray cones of the second hole pitch circles 28 are between the spray cones of the first hole pitch circles 26. This means that, viewed from below or above the fuel injection valve 36, the nozzle openings 24 of the second hole pitch circle 28 deviate from a bisector of an angle between two adjacent nozzle openings 22 of the first hole pitch circle by less than 20 °, wherein the nozzle openings 24 of the second hole pitch circle 28 are particularly preferably arranged symmetrically to this bisector.

Fig. 3 shows a first operating state of the internal combustion engine 10 according to the invention, the internal combustion engine 10 having a variable compression ratio epsilon and having a fuel nozzle 20, the fuel nozzle 20 having a plurality of

nozzle openings

22, 24 on

different pitch circles

26, 28. The variable compression ratio epsilon can be achieved here by adjusting the piston position in the top dead center. The pitch circles 26, 28 have different cone angles α, β for the injected jet of metered fuel, so that different piston positions are taken into account depending on the compression ratio ∈. In the first operating state a, the internal combustion engine 10 has a high compression ratio epsilon₁At a lower torque T and a correspondingly lower injection quantity, a higher piston position is set for the piston 18. Here, the compression ratio ε₁In a value between 17 and 23. Such a high compression ratio ε₁The object of (1) is to improve combustion stability at a later combustion center of gravity position. Late combustion center of gravity position and high compression ratio epsilon₁The combination of (1) facilitates a rapidly heated exhaust gas aftertreatment component, such as a NOx storage catalyst, an oxygen catalyst, a catalyst for selective catalytic reduction of nitrogen oxides (SCR catalyst), and/or a particulate filter, in the vicinity of the engine in order to bring the exhaust gas aftertreatment component to the start-up temperature as soon as possible after a cold start of the internal combustion engine 10. The combination is furthermore advantageous in order to achieve the required temperature and correspondingly to heat the exhaust gas aftertreatment component, so that the exhaust gas aftertreatment component can be operated quickly and stably. The first operating state may also be used in particular for heating the particle filter to a regeneration temperature.

The position of the center of gravity of combustion can be set at such a high compression ratio epsilon₁Down to between 20 and 50 ° ca (crank angle) after piston 18 reaches top dead center, such combustion center of gravity position being achieved by low pressure of direct injection diesel engines known from the prior artScaling cannot be achieved. For this purpose, a main injection with a center of gravity position of the piston 18 after reaching top dead center, preferably 5 ° ca to 20 ° ca, is of interest. The main injection is preferably supplemented by a pilot injection immediately before the main injection, in which the amount of injected fuel is not more than 10% of the amount of the main injection and is in the range of 1mg to 3.5mg of fuel. Here, the pilot injection should not precede the main injection by more than 50 ° ca. Furthermore, for the purpose of carrying out post-oxidation in the combustion chamber with increased particle emissions occurring in the later combustion center of gravity position, it makes sense to provide an earlier post-injection in which an injection quantity of not more than 20% of the injection quantity of the main injection is metered into the combustion chamber 16. Here, the injection amount of the post injection is in the range of 1mg to 8mg of fuel, and is preferably injected between 5 ° ca to 50 ° ca after piston 18 reaches the top dead center. At smaller injection quantities in the first operating state, fuel is injected into the combustion recess 32 of the piston 18 only through the nozzle openings 22 on the first hole pitch circle 26 having the wider cone angle α.

Fig. 4 shows a second operating state of the internal combustion engine 10, in which the compression ratio epsilon is reduced relative to the first operating state, so that a good compromise between power requirement, drive load and particle NOx balance is achieved. The value of the compression ratio epsilon for the second operating state B is here in the range of 13 to 17. Higher compression ratio epsilon₁With a lower compression ratio epsilon₂The valence difference (Spreizeng) between them is preferably at most 8 units, particularly preferably 2.5 to 6 units, ideally 3 to 4 units. Both stepless adjustment of the compression ratio and two-point or three-point adjustment are conceivable. Based on a higher compression ratio ε₁With a lower compression ratio epsilon₂But the method can also be implemented in a multipoint or stepless regulation.

The determination of the optimum compression ratio is preferably effected by means of a speed and torque characteristic curve or by means of an injection quantity characteristic curve, in which a high compression ratio epsilon, which increases the exhaust gas temperature (but is less favorable for efficiency), is to be achieved₁The rotational speed n of less than 2500 rpm and the torque or injection quantity of less than half the maximum value are set in the vicinity. In order to describe the consumption as advantageously as possible, it is expedient to correct forBasic setting of the amount of further influence. With regard to the measured or modeled temperature of at least one component of an exhaust system downstream of the internal combustion engine 10, at a lower temperature T₁In particular below 150 c, the basic setting is shifted towards higher rotational speeds and/or injection quantities or torques. On the contrary, at higher temperatures T₂In particular at temperatures above 350 ℃, it is also possible to provide smaller characteristic curve regions with a high compression ratio epsilon₁At a higher temperature T₂Especially above 350 c, without the need for additional heating or incubation. If necessary, a higher temperature T in the exhaust gas duct₂The high compression ratio epsilon can be abandoned in the range of the characteristic curve₁The operation of (2). A further influencing quantity for determining the current optimal compression ratio epsilon may be: coolant temperature, ambient or intake air temperature, charge pressure, lubricating oil temperature, charge air temperature, peak pressure in the combustion chamber 16, and further measured or modeled temperatures in particular in the exhaust gas channel of the internal combustion engine. Further, a high compression ratio ε is set₁To low compression ratio epsilon₂The conversion lag between.

The adjustment of the compression ratio epsilon, in particular the two-point adjustment proposed, can be carried out by varying the effective connecting rod length l_PThe process is carried out. Alternatively, it may be considered to raise or lower the cylinder head 14 so as to adjust the compression ratio epsilon. The conversion of the jet 22 injection through the first hole pitch circle 26 into the injection through all the

jets

22, 24 can be achieved by a corresponding shaping of the nozzle needle 46 and the nozzle body 44, wherein the nozzle needle 46 can be controlled directly or indirectly.

List of reference numerals

10 internal combustion engine

12 engine cylinder

14 cylinder head

16 combustion chamber

18 piston

20 fuel nozzle

22 (on the first hole pitch circle) spout

24 (on the second hole pitch circle) spout

26 first hole pitch circle

28 second hole pitch circle

30 (of the piston) end face

32 combustion pit

34 connecting rod

36 fuel injection valve

38 cylinder wall

40 inlet valve

42 exhaust valve

44 nozzle body

46 nozzle needle valve

48 valve seat

50 nozzle tip

52 conical section

54 air inlet camshaft

56 exhaust camshaft

58 crankshaft

Compression ratio of epsilon

ε₁Compression ratio at higher compression

ε₂Compression ratio at lower compression level

D₁Diameter of the nozzle on the pitch circle of the first hole

D₂Diameter of the nozzle on pitch circle of the second hole

D₃Diameter of first hole pitch circle

D₄Diameter of second hole pitch circle

l_PLength of connecting rod

n number of revolutions

T torque

T₁First temperature in exhaust gas passage

T₂Second temperature in exhaust gas passage

Claims

1. Internal combustion engine (10) having an engine block (12) and a cylinder head (14), wherein the internal combustion engine (10) comprises at least one combustion chamber (16), in which combustion chamber (16) a piston (18) for compressing an air mixture for combustion is arranged, and wherein in the cylinder head (14) at least one fuel injection valve (36) is arranged, which fuel injection valve (36) comprises a fuel injection nozzle (20),

it is characterized in that the preparation method is characterized in that,

the compression ratio (epsilon) of the internal combustion engine (10) is variable, and the fuel nozzle (20) has a plurality of nozzle orifices (22, 24), the nozzle orifices (22, 24) being arranged on two different pitch circles (26, 28),

wherein the orifices (22) of the first orifice pitch circle (26) have a flatter spray angle (alpha) than the orifices (24) of the second orifice pitch circle (28),

wherein the internal combustion engine (10) can be operated in a first operating state with a high compression ratio (epsilon)₁) In operation, fuel is injected into the combustion chamber (16) exclusively through the ports (22) of the first hole pitch circle (26).

2. Internal combustion engine (10) according to claim 1, characterized in that the outlet orifices (22) of the first orifice pitch circle (26) have a smaller diameter (D) than the outlet orifices (24) of the second orifice pitch circle (28)₁)。

3. The internal combustion engine (10) of claim 1, wherein the number of ports (22) on the first orifice pitch circle (26) is greater than the number of ports (24) on the second orifice pitch circle (28).

4. Internal combustion engine (10) according to claim 1, characterized in that the top of the fuel nozzle (20) facing the combustion chamber (16) of the internal combustion engine (10) is conical in shape, so that the first bore pitch circle (26) has a larger diameter (D) than the second bore pitch circle (28)₄) Smaller diameter (D)₃)。

5. An internal combustion engine (10) as set forth in claim 1 wherein the injection angle (α) of the ports (22) of the first hole pitch circle (26) is between 155 ° and 175 °, and the injection angle (β) of the ports (24) of the second hole pitch circle (28) is between 90 ° and 170 °.

6. Internal combustion engine (10) according to claim 1, characterized in that the internal combustion engine (10) is designed as a self-igniting internal combustion engine (10) according to the diesel principle.

7. An internal combustion engine (10) according to claim 1, characterized in that the compression ratio(s) of the internal combustion engine (10) is between 13 and 23, wherein the compression ratio(s) can be varied steplessly or in two or more specific steps.

8. Internal combustion engine (10) according to claim 7, characterized in that the compression ratio is 17 ≦ ε in the first level with higher degree of compression₁23, and 13 ≦ ε in the second level having the lower degree of compression₂Less than or equal to 17.

9. Internal combustion engine (10) according to claim 1, characterized in that the internal combustion engine (10) is capable of a low compression ratio (epsilon) in the second operating state₂) In operation, fuel is injected both through the nozzle openings (22) of the first hole pitch circle (26) and through the nozzle openings (24) of the second hole pitch circle (28).

10. An internal combustion engine (10) according to claim 1, characterized in that the compression ratio (epsilon) is changed by changing the effective connecting rod length (l) of the connecting rod (34) connected to the piston (18)_P) Can be changed.

11. Internal combustion engine (10) according to claim 1, characterized in that the piston (18) has a combustion recess (32) on its end face (30) facing the fuel nozzle (20).

12. A method of operating an internal combustion engine (10), the internal combustion engine (10) having an engine block (12) and a cylinder head (14), wherein the internal combustion engine (10) comprises at least one combustion chamber (16), in which combustion chamber (16) a piston (18) for compressing an air mixture for combustion is arranged, and wherein in the cylinder head (14) at least one fuel injection valve (36) is arranged, which fuel injection valve (36) comprises a fuel injection nozzle (20),

it is characterized in that the preparation method is characterized in that,

the compression ratio (epsilon) of the internal combustion engine (10) is variable, and the fuel injection nozzle (20) has a plurality of injection ports (22, 24), which injection ports (22, 24) are arranged on two different pitch circles (26, 28), wherein, in a first operating state, at a low load, a high compression ratio (epsilon)₁) Operating the internal combustion engine (10) and injecting fuel into the combustion chamber (16) only through the outlet openings (22) on the first hole pitch circle (26) of the fuel injection nozzle (20), and wherein in a second operating state, a low compression ratio (epsilon) is provided at high load₂) An internal combustion engine (10) is operated, wherein fuel is injected into the combustion chamber (16) via the outlet openings (22, 24) of the two hole pitch circles (26, 28).

13. Method for operating an internal combustion engine (10) according to claim 12, characterized in that the lower temperature (T) in the exhaust gas channel of the internal combustion engine (10)₁) At a high compression ratio (ε)₁) Operating the internal combustion engine (10) and the higher temperature (T) in the exhaust gas channel₂) At a low compression ratio (ε)₂) The internal combustion engine (10) is operated.