Internal combustion engine

Abstract

The invention relates to an internal combustion engine (1) having a cylinder head (3), which is cooled according to a top-down cooling concept, for at least one cylinder (2), the cylinder head having, per cylinder (2), at least one injection device (130) with an injector (13) for directly introducing a fuel into a combustion chamber (12), wherein the cylinder head (3) has at least one lower cooling chamber (8) adjacent to a fire deck (7) and at least one upper cooling chamber (9) spaced apart from the fire deck (7), wherein the upper cooling chamber (9) and the lower cooling chamber (8) are separated from one another by an intermediate deck (10), wherein at least one overflow channel (11, 26) is formed between the upper cooling chamber (9) and the lower cooling chamber (8). In order to enable high engine braking powers and to avoid irregular combustion, it is provided that the injection device (130) is at least partially surrounded by a flow-guiding wall (31) in the region of an opening (16) of the injector (13).

Description

[0001] internal combustion engine

[0002] The invention relates to an internal combustion engine, in particular a hydrogen-powered internal combustion engine, with a cylinder head cooled according to a top-down cooling concept for at least one cylinder, which cylinder head has at least one injection device with an injector for the direct introduction of a fuel, in particular a gaseous fuel, into a combustion chamber, wherein the cylinder head has at least one lower cooling chamber bordering a fire deck and at least one upper cooling chamber spaced from the fire deck, wherein the upper cooling chamber and the lower cooling chamber are separated from one another by an intermediate deck, wherein at least one overflow channel is formed between the upper cooling chamber and the lower cooling chamber.

[0003] Internal combustion engines with cylinder heads cooled according to a top-down cooling concept are known, for example, from WO 2020 / 011926 A1 or WO 2020 / 051607 A1. In an internal combustion engine with a top-down cooling concept, the cylinder head has at least one lower cooling chamber adjacent to a fire deck and at least one upper cooling chamber spaced from the fire deck, wherein the lower cooling chamber and the upper cooling chamber are separated from one another by an intermediate deck. The upper cooling chamber and the lower cooling chamber are fluidly connected to one another via at least one crossover - for example, in the region of a central sleeve for accommodating a spark plug or an injection device. A top-down cooling concept refers to cylinder head cooling in which coolant flows through the cylinder head from top to bottom. Thus, the upper cooling chamber and the lower cooling chamber flow through the upper cooling chamber one after the other.

[0004] Injector sleeves are used for installing injectors through coolant-carrying areas in the cylinder head. These enable targeted coolant routing and a dry area for the injector. Depending on the injector's installation position, it may be necessary to provide differently oriented outlet openings on the injector. These specifically oriented outlet openings are usually realized using so-called jet orientation caps or blow caps, which are attached to the injector. For injectors arranged in the cylinder head for injecting gaseous media into a combustion chamber, it is therefore common practice to provide jet orientation caps on the injectors to ensure a specific orientation of the jet of the injected medium. These jet orientation caps, which define the spray pattern of the injected fuel, are usually attached directly to the injector nozzles and are therefore an integral part of the injector.An air gap is formed between the jet orientation cap and the cylinder head. Therefore, the jet orientation caps are decoupled from the cylinder head, preventing heat transfer to the cylinder head.

[0005] From WO 2023 / 052263 A1 an injection nozzle for gaseous fuels for an internal combustion engine is known, wherein a nozzle cap is detachably clipped onto the injection nozzle in the area of ​​the nozzle tip of the injection nozzle.

[0006] WO 2023 / 137515 A1 describes a hydrogen-powered internal combustion engine with a hydrogen injector for directly injecting hydrogen into a cylinder. The injector has a nozzle cap near a distal end, which is fitted over an external shaft of the injector.

[0007] Compared to diesel injectors, conventional injectors for direct hydrogen injection / injection have the disadvantage of a relatively low temperature limit for the injector nozzle / valve area. While this is not a problem during fired operation due to cooling by the flowing fuel, relatively high temperatures occur in the combustion chamber and in the injector nozzle area during engine braking. The limit of these temperatures is defined by the injector nozzle temperature. If this temperature must be significantly reduced, this in turn means a reduction in the achievable braking performance.

[0008] Another issue in combination with H2 fuel is auto-ignition due to higher local temperatures in the combustion chamber. Here, it is necessary to avoid so-called "hot spots" in the combustion chamber. One of these hot spots is the blow cap, which is often required for H2 DI engines and defines the fuel spray pattern in the combustion chamber.

[0009] The object of the invention is to enable high engine braking performance and to avoid irregular combustion.

[0010] According to the invention, this is achieved in an internal combustion engine of the type mentioned at the outset in that the injection device is at least partially surrounded in the region of an orifice of the injector by a flow guide wall - in particular a collar-shaped one - preferably formed by the fire deck of the cylinder head.

[0011] The flow guide wall is preferably arranged between the injection device and the lower cooling chamber. The injection device is advantageously arranged outside a region of the cylinder center.

[0012] One embodiment variant of the invention provides that at least one first overflow channel is arranged in the region of the cylinder center of the cylinder - preferably in the region of a spark plug sleeve - between the upper cooling chamber and the lower cooling chamber, and that the flow guide wall is arranged in the region of the injection device in such a way that a main coolant flow coming from the at least one first overflow channel is deflected in the lower cooling chamber by the flow guide wall and divided into two external cooling channels on either side of the injection device.

[0013] It is particularly advantageous if at least one second overflow channel is arranged outside the region of the cylinder center in the region of the injection device and the flow guide wall is arranged in the region of the injection device in such a way that a partial coolant flow coming from the at least one second overflow channel is deflected by the flow guide wall to a valve bridge of the fire deck and is preferably entrained by the main coolant flow.

[0014] The flow guide wall redirects a main coolant flow coming from the cylinder center in the lower cooling chamber and divides it between two external cooling channels on either side of the injection device. At the same time, a partial coolant flow is redirected from the upper cooling chamber to the fire deck and entrained by the main coolant flow. The coolant flows do not directly collide, thus avoiding pressure losses. Furthermore, the main coolant flow is pushed toward the fire deck by the partial coolant flow, thereby improving the cooling effect in the fire deck area.

[0015] In one embodiment of the invention, it is provided that a jet orientation cap is arranged in the region of the mouth of the injector, wherein the jet orientation cap is integrated into an injector sleeve receiving the injector or is fastened to the injector sleeve.

[0016] In an internal combustion engine with a so-called top-down cooling concept, the cylinder head has at least one lower cooling chamber adjacent to a fire deck and at least one upper cooling chamber spaced from the fire deck, wherein the lower cooling chamber and the upper cooling chamber are separated from one another by an intermediate deck. The upper cooling chamber and the lower cooling chamber are fluidly connected to one another via at least one crossover - for example, in the area of ​​a central spark plug sleeve. A top-down cooling concept refers to cylinder head cooling in which coolant flows through the cylinder head from top to bottom. This means that coolant flows through the upper cooling chamber and the lower cooling chamber one after the other. The terms lower cooling chamber and upper cooling chamber are used here only to distinguish them and are not to be understood as geodetic information.

[0017] In one embodiment of the invention, a receiving bore for receiving the injector sleeve and / or the jet orientation cap is arranged at least partially in the intermediate deck, with at least one second overflow channel being formed between the upper cooling chamber and the lower cooling chamber in the region of the receiving bore. Preferably, several second overflow channels are arranged rotationally symmetrically with respect to a longitudinal axis of the injector. This makes it possible to adapt and optimize the cooling of the injector sleeve and the jet orientation cap to the requirements.

[0018] In one embodiment of the invention, the jet orientation cap comprises a number of radial ribs evenly distributed around the circumference, with the second overflow channels being formed by longitudinal channels with a radially outwardly open cross-section between each two adjacent radial ribs. Alternatively or additionally, at least one second overflow channel may be formed by a longitudinal channel with a closed cross-section in the jet orientation cap.

[0019] Preferably, at least one second overflow channel is formed by an annular gap between the jet orientation cap and the intermediate deck.

[0020] Preferably, the jet orientation cap is adjacent to the flow guide wall.

[0021] In contrast to known arrangements, the jet orientation cap is not physically connected to the injector, but rather to the injector sleeve of the injector itself, or is formed as a single piece with it. The heat from the jet orientation cap can thus be dissipated directly to the injector sleeve, which is in physical contact with the cylinder head. The injector sleeve is arranged in at least one receiving bore of the cylinder head and is connected to the cylinder head by a force-locking and / or positive-locking connection, for example, by a screw connection, a press connection, and / or an adhesive connection.

[0022] According to the invention, at least one injector per cylinder is provided for the direct introduction of a fuel, in particular a gaseous fuel, into a combustion chamber, i.e., the internal combustion engine is operated, in particular, with a gaseous fuel—for example, hydrogen. Alternatively, it may also be advantageous if the at least one injector per cylinder is designed for the introduction of a liquid fuel, so that the internal combustion engine is advantageously operated with liquid fuel.

[0023] Preferably, the jet orientation cap and the injector sleeve form a multi-part assembly unit or a one-piece sleeve unit. In a two-part design, the jet orientation cap can advantageously be pre-assembled to the injector sleeve and inserted together with the injector sleeve into at least one receiving bore of the cylinder head.

[0024] The jet orientation cap and injector sleeve can be formed as separate parts. In this case, the assembly unit consists of two parts. Alternatively, it is also possible to form the jet orientation cap integrally with the injector sleeve, thus forming the assembly unit as a single piece. The jet orientation cap is thus part of the injector sleeve.

[0025] The beam orientation cap can have one or more beam openings. The beam openings can be arranged symmetrically or asymmetrically within the beam orientation cap.

[0026] To improve heat dissipation, it is advantageous if the beam orientation cap is directly adjacent to at least one—preferably first—cooling chamber and is at least wetted by, and preferably surrounded by, coolant. The beam orientation cap is thus directly cooled by the coolant.

[0027] Advantageously, the injector sleeve is designed as a wet sleeve and is also directly adjacent to at least one - preferably second - cooling chamber and is at least wetted by coolant, preferably flows around it.

[0028] In one embodiment of the invention, it is provided that at least one cooling chamber - preferably the upper cooling chamber - is fluidly connected to a cylinder block cooling chamber in the cylinder block via a coolant transfer channel in the fire deck, wherein a bypass channel branching off from the coolant transfer channel leads directly to the jet orientation cap.

[0029] In order to ensure a gas-tight seal between the jet orientation cap and the injector sleeve, it is advantageous if at least one sealing element is arranged between the jet orientation cap and the injector sleeve, wherein the jet orientation cap preferably has at least one first annular groove in the region of an outer circumferential surface for receiving the at least one sealing element - preferably designed as an O-ring. The O-ring lies in the first annular groove of the outer circumferential surface and is pressed against an inner circumferential surface of the injector sleeve. It is particularly advantageous if the inner circumferential surface has a second annular groove in the region of the sealing element. The sealing element, which can be elastic for example, comes to rest in the second annular groove when the jet orientation cap is pushed onto the injector sleeve and thus effects axial positioning and fixing of the jet orientation cap.The injector sleeve is pressed onto the sealing element. The sealing element holds the jet orientation cap in place.

[0030] Alternatively or additionally, it can be provided that the injector has a first sleeve part and a second sleeve part, wherein at least one sealing element is arranged between the first sleeve part and the second sleeve part of the injector sleeve, and wherein the first sleeve part preferably has at least one first annular groove in the region of an outer circumferential surface for receiving the at least one sealing element - preferably designed as an O-ring. The O-ring lies in the first annular groove in the outer circumferential surface of the first sleeve part and is pressed against an inner circumferential surface of the second sleeve part. It is particularly advantageous if the inner circumferential surface has a second annular groove in the region of the sealing element.The elastic sealing element, for example, comes to rest in the second annular groove when the first sleeve part is pushed into the second sleeve part of the injector sleeve, thus ensuring axial positioning and fixation of the two sleeve parts. The second sleeve part is pressed onto the sealing element. The sealing element holds the two injector parts together.

[0031] According to one embodiment of the invention, the jet orientation cap has a preferably conical annular shoulder, wherein the shoulder rests, preferably in a gas-tight manner, on an annular support surface of the cylinder head that corresponds to the shoulder. As an alternative to a conical support surface, the support surface can also be designed as a flat axial surface normal to the injector's longitudinal axis. The jet orientation cap is pressed against the support surface of the cylinder head by the injector sleeve and is thus fixed in the axial direction by it. The shoulder and support surface are pressed together and connected in a gas-tight manner, thus preventing stray leakage between the jet orientation cap and the cylinder head.

[0032] Furthermore, within the scope of the invention, it is provided that the jet orientation cap is correctly positioned on the injector sleeve via a positioning element, preferably formed by a pin. The rotational position of the jet orientation cap is defined via the positioning element. The positioning element engages positively in a recess in the jet orientation cap and / or the injector sleeve. The positioning element can be formed as a separate part or integrally with the jet orientation cap or the injector sleeve. The invention is explained in more detail below with reference to the non-limiting exemplary embodiments shown in the following figures. These schematically show:

[0033] Fig. 1 shows an internal combustion engine according to the invention;

[0034] Fig. 2 shows a cylinder head of the internal combustion engine according to the invention in a first embodiment in a sectional view;

[0035] Fig. 3 shows a cylinder head of the internal combustion engine according to the invention in a second embodiment in a sectional view;

[0036] Fig. 4 shows a cylinder head of the internal combustion engine according to the invention in a third embodiment in a sectional view;

[0037] Fig. 5 shows a cylinder head of the internal combustion engine according to the invention in a fourth embodiment in a sectional view;

[0038] Fig. 6 shows an injector in a further embodiment variant in a section along the line VI-VI in Figs. 2 to 5;

[0039] Fig. 7 shows an injector in an alternative embodiment in a section analogous to Fig. 6;

[0040] Fig. 8 shows a cylinder head of the internal combustion engine according to the invention in a fifth embodiment in a sectional view; and

[0041] Fig. 9 shows this cylinder head in a section along the line IX-IX in Fig. 8.

[0042] Fig. 1 shows a liquid-cooled hydrogen internal combustion engine 1 according to the invention for at least one cylinder 2, with a cylinder head 3, which is firmly connected to a cylinder block 4. Reference numeral 2b indicates a piston reciprocating in the cylinder 2.

[0043] The illustrated cylinder head 3 has a spark plug 5 arranged centrally in the region of the cylinder axis 2a, which is arranged in a spark plug sleeve 6. The cylinder head 3 has a lower cooling chamber 8 adjacent to the fire deck 7 and an upper cooling chamber 9, which is separated from the lower cooling chamber 8 by an intermediate deck 10. The cylinder head 3 is cooled according to a so-called top-down cooling concept. This means that the coolant - for example, from the cylinder block 4 - is first fed to the upper cooling chamber 9 and flows via at least one first overflow channel 26 in the intermediate deck 10 - for example, in the region of the spark plug sleeve 6 arranged in the cylinder center 35 - into the lower cooling chamber 8, as indicated by the arrows P.The cylinder head 3 has at least one injection device 130 per cylinder 2, arranged outside a cylinder center 35 formed by the cylinder axis 2a, with an injector 13 for directly introducing fuel into a combustion chamber 12 of the cylinder 2. The injection device 130 is thus spaced further from the cylinder center 35 than the spark plug sleeve 6 and is arranged in particular in the region of or outside a valve bridge 34 of the fire deck 7. The injection device 130, with its sleeve part 14, directly borders the lower cooling chamber 8, wherein the sleeve part 14 is wetted by coolant.

[0044] In the described embodiments, the injector 13 is designed to inject hydrogen gas into the combustion chamber 12. However, the invention is equally suitable for injectors 13 for injecting liquid fuel.

[0045] Reference numeral 13a denotes the longitudinal axis of the injector 13, which is inclined, for example, at an angle between 30° and 60° with respect to the cylinder head plane E. The injector 13 is arranged in the injector sleeve 14 fastened in the cylinder head 3. The injector sleeve 14 is inserted into a receiving bore 15 of the cylinder head 3 and is connected to the cylinder head 3 in a force-locking and / or form-locking manner, for example by a screw connection, a press connection, and / or an adhesive connection. For sealing, at least one seal 28 can be provided between the injector sleeve 14 and the cylinder head 3 (Fig. 2, Fig. 3).

[0046] In the area of ​​the orifice 16 of the injector 13 into the combustion chamber 12, the injection device 130 has a jet orientation cap 17. The jet orientation cap 17 of the injector 13 has one or more outlet openings 27 and serves to ensure a specific orientation of the gas injection jet of the gas injected through the injector 13. The jet orientation cap 17 defines the jet pattern S of the fuel introduced into the combustion chamber 12.

[0047] In each of the embodiments shown in the figures, the jet orientation cap 17 is integrated into the injector sleeve 14 receiving the injector 13 or is attached to the injector sleeve 14.

[0048] The jet orientation cap 17 and the injector sleeve 14 can, for example, form an assembly unit. In this case, the jet orientation cap 17 is pre-assembled to the injector sleeve 14 and inserted together with the injector sleeve 14 into the receiving bore 15 of the cylinder head 3.

[0049] The jet orientation cap 17 directly borders the lower cooling chamber and is surrounded by coolant. The injector sleeve 14 is designed as a wet sleeve and also borders the upper cooling chamber 9 and is also surrounded by coolant.

[0050] The receiving bore 15 for receiving the injector sleeve 14 and the jet orientation cap 17 is arranged at least partially in the intermediate deck 10. In the region of the receiving bore 15, at least one second overflow channel 11 is formed between the upper cooling chamber 9 and the lower cooling chamber 8 in order to enable the coolant flow P between the upper cooling chamber 9 and the lower cooling chamber 8. The second overflow channels 11 are arranged, for example, rotationally symmetrically with respect to the injector longitudinal axis 13a of the injector 13, in particular in the jet orientation cap 17 (see Fig. 5 and Fig. 6). However, other shapes or arrangements of the second overflow channels 11 are also possible.

[0051] In the embodiment of the invention illustrated in Figs. 1 and 2, the upper cooling chamber 9 is fluidly connected to a cylinder block cooling chamber (not shown) in the cylinder block 4 via a coolant transfer channel 24 in the fire deck 7, with a bypass channel 25 branching off from the coolant transfer channel 24 leading directly to the jet orientation cap 17. Thus, the jet orientation cap 17 is cooled directly by relatively cool coolant, which is branched off from the coolant transfer channel 24 before reaching the upper cooling chamber 9.

[0052] In Fig. 3, however, the cooling of the jet orientation cap 17 is effected essentially by the at least one second overflow channel 11 passing from the upper cooling chamber 9 into the lower cooling chamber 8.

[0053] The embodiment shown in Fig. 3 further differs from Fig. 2 in that the jet orientation cap 17 is correctly positioned in the cylinder head 3 via a positioning element 18. The positioning element 18 can be formed, for example, by a pin arranged between the jet orientation cap 17 and the cylinder head 3. A positioning element 18 is particularly advantageous in embodiments of the invention in which the outflow openings 27 are not concentric with respect to the injector's longitudinal axis 13a.

[0054] The jet orientation cap 17 and / or the injector sleeve 14 of the injection device 130 can be designed in one piece or in two pieces.

[0055] In the embodiments shown in Fig. 1 to Fig. 3, the jet orientation cap 17 is formed in one piece but separately from the injector sleeve 14. In the embodiments shown in Fig. 1 to Fig. 3, in which the jet orientation cap 17 is formed separately from the injector sleeve 14, at least one sealing element 19 is arranged between the jet orientation cap 17 and the injector sleeve 14. The sealing element 19 can be an O-ring, for example. The jet orientation cap 17 has a first annular groove 20 in the region of an outer circumferential surface for receiving the sealing element 19. Furthermore, a second annular groove 21 can be provided in an inner circumferential surface of the injector sleeve 14 in the region of the sealing element 19 for receiving the sealing element 19 (see Fig. 4). This defines an axial position of the jet orientation cap 17 on the injector sleeve 14 and secures the jet orientation cap 17 on the injector sleeve 14.

[0056] Fig. 4 shows an embodiment of the invention in which the injector sleeve 14 has a first sleeve part 14a and a second sleeve part 14b, wherein the first sleeve part 14a is detachably inserted into the second sleeve part 14b and is sealingly connected to the latter via a sealing element 19a, for example designed as an O-ring seal. The first sleeve part 14a is tightly connected to the fire deck 7 of the cylinder head 3 via a cylindrical receiving surface 15a and / or a support surface 23. The jet orientation cap 17 has at least one outflow opening 27 directed into the combustion chamber 12. The first sleeve part 14a is made of thermally conductive material and serves as a support and seal for the injector 14. The jet orientation cap 17 can be connected to the first sleeve part 14a by a press connection, an adhesive connection, a screw connection, a welded connection, or the like.

[0057] Fig. 5 shows an embodiment variant of the invention in which the jet orientation cap 17 is formed integrally with the injector sleeve 14 and forms a sleeve unit E.

[0058] In all embodiments shown, the jet orientation cap 17 has a conical annular shoulder 22. The shoulder 22 rests in a gas-tight manner on the annular support surface 23 of the cylinder head 3, which corresponds to the shoulder 22, in order to enable sealing on the combustion chamber side.

[0059] In a variant not shown, the support surface 23 is not conical, but is designed as a flat axial surface normal to the injector longitudinal axis 13a.

[0060] Adjacent to the support surface 23 axially in the direction of the cylinder head plane s is a cylindrical region 29 formed by the jet orientation cap 17 or the injector sleeve 14, which is designed as a press fit or transition fit with respect to the cylindrical receiving surface 15a of the cylinder head 3 (Fig. 4, Fig. 5). This enables additional sealing and improved heat transfer.

[0061] Fig. 6 and Fig. 7 show cross sections of injectors 14 in two different embodiments according to the invention, wherein second overflow channels 11 between the upper cooling chamber 9 and the lower cooling chamber 8 are formed at least partially by a channel body K, which is formed by the jet orientation cap 17 (see Fig. 2, Fig. 3), by the first sleeve part 14a of the injector sleeve 14 (see Fig. 4) or by the sleeve unit E comprising injector sleeve 14 and jet orientation cap 17 (Fig. 5).

[0062] In the embodiment shown in Fig. 6, the channel body K formed by the jet orientation cap 17 or the first sleeve part 14a of the injector sleeve 14 or the sleeve unit E has a number of radial ribs 30 evenly distributed around the circumference, wherein the second overflow channels 11 are formed by longitudinal channels with a cross-section open radially outward between each two adjacent radial ribs 30. The radial ribs 30 increase the water-wetted surface and improve cooling.

[0063] Fig. 7 shows an embodiment variant of the invention in which the second overflow channels 11 are formed by longitudinal channels with a closed cross-section in the channel body K.

[0064] 8 and 9 show a cylinder head 3 in a variant similar to FIG. 2 or FIG. 3. The injection device 130 is surrounded in the region of the orifice 16 of the injector 13 on the side of the lower cooling chamber 8 by a collar-shaped flow guide wall 31 formed by the fire deck 7 of the cylinder head 3. The flow guide wall 31 is arranged between the injection device 130 and the lower cooling chamber 8. The jet orientation cap 17 arranged in the region of the orifice 16 of the injector 13 is fastened here to the injector sleeve 14. The jet orientation cap 17 borders directly on the flow guide wall 31. In particular, the flow guide wall 31 forms part of the annular support surface 23 for the annular shoulder 22 of the jet orientation cap 17. The flow guide wall 31 is formed by a hollow cylinder segment-shaped extension on the fire deck 7, which projects from the fire deck 7 in the direction of the lower cooling chamber 8.The flow guide wall 31, which is, for example, sleeve-segment-like, is designed in the exemplary embodiment essentially concentrically to the injector's longitudinal axis 13a. The flow guide wall 31 deflects the main coolant flow PI in the lower cooling chamber 8, coming from at least one first overflow channel 26 in the region of the center of the cylinder 2, i.e., the cylinder axis 2a, and divides it between the two outer cooling channels 32, 33 (Fig. 9). As a result, the partial coolant flow P2—coming from the second overflow channels 11 between the upper cooling chamber 9 and the lower cooling chamber 8 around the injector 13—is also deflected to the valve bridge 34 of the fire deck 7 and entrained by the main coolant flow PI. The advantage of this solution is that the coolant flows P1, P2 do not directly collide, thus reducing the pressure loss. The main coolant flow PI is pushed to the fire deck for a longer time by the partial coolant flow P2. This improves the cooling effect.

Claims

P A T E N T A N S P R Ü C H E 1. Internal combustion engine (1), in particular a hydrogen-powered internal combustion engine (1), with a cylinder head (3) cooled according to a top-down cooling concept for at least one cylinder (2), which has at least one injection device (130) with an injector (13) for the direct introduction of a fuel, in particular a gaseous fuel, into a combustion chamber (12) per cylinder (2), wherein the cylinder head (3) has at least one lower cooling chamber (8) bordering a fire deck (7) and at least one upper cooling chamber (9) spaced from the fire deck (7), wherein the upper cooling chamber (9) and the lower cooling chamber (8) are separated from one another by an intermediate deck (10), wherein at least one overflow channel (11, 26) is formed between the upper cooling chamber (9) and the lower cooling chamber (8), characterized in that the injection device (130) is at least partially surrounded in the region of an opening (16) of the injector (13) by a,preferably surrounded by the flow guide wall (31) formed - in particular collar-shaped - by the fire deck (7) of the cylinder head (3).

2. Internal combustion engine (1) according to claim 1, characterized in that the flow guide wall (31) is arranged between the injection device (130) and the lower cooling chamber (8), wherein preferably the injection device (130) is arranged outside a region of a cylinder center (35).

3. Internal combustion engine (1) according to claim 1 or 2, characterized in that at least one first overflow channel (26) is arranged in the region of the cylinder center (35) of the cylinder (2) - preferably in the region of a spark plug sleeve (6) - between the upper cooling chamber (9) and the lower cooling chamber (8), and in that the flow guide wall (31) is arranged in the region of the injection device (130) in such a way that a main coolant flow (PI) coming from the at least one first overflow channel (26) is deflected in the lower cooling chamber (8) by the flow guide wall (31) and divided between two external cooling channels (32, 33) on either side of the injection device (130).

4. Internal combustion engine (1) according to one of claims 1 to 3, characterized in that at least one second overflow channel (11) is arranged outside the region of the cylinder center (35) of the cylinder (2) in the region of the injection device (130), and in that the flow guide wall (31) is arranged in the region of the injection device (130) in such a way that a partial coolant flow (P2) coming from the at least one second overflow channel (11) is directed through the flow guide wall (31) to a valve bridge (34) of the fire deck (7) and is preferably entrained by the main coolant flow (PI).

5. Internal combustion engine (1) according to one of claims 1 to 4, characterized in that a jet orientation cap (17) is arranged in the region of the mouth (16) of the injector (13), wherein the jet orientation cap (17) is integrated into an injector sleeve (14) receiving the injector (13) or is fastened to the injector sleeve (14).

6. Internal combustion engine (1) according to claim 5, characterized in that a receiving bore (15) for receiving the injector sleeve (14) and / or the jet orientation cap (17) is arranged at least partially in the intermediate deck (10), wherein in the region of the receiving bore (15) the at least one second overflow channel (11) is formed between the upper cooling chamber (9) and the lower cooling chamber (8), wherein preferably a plurality of second overflow channels (11) are arranged rotationally symmetrically with respect to an injector longitudinal axis (13a) of the injector (13).

7. Internal combustion engine (1) according to claim 5 or 6, characterized in that the jet orientation cap (17) - or the injector sleeve (14) - has a number of radial ribs (30) evenly distributed around the circumference, wherein the second overflow channels (11) are formed by longitudinal channels with a cross-section open radially outwards between each two adjacent radial ribs (30).

8. Internal combustion engine (1) according to one of claims 5 to 7, characterized in that at least one second overflow channel (11) is formed by a longitudinal channel with a closed cross-section in the jet orientation cap (17) - or in the injector sleeve (14).

9. Internal combustion engine (1) according to one of claims 5 to 8, characterized in that at least one second overflow channel (11) is formed by an annular gap between the intermediate deck (10) and the jet orientation cap (17) or between the intermediate deck (10) and the injector sleeve (14).

10. Internal combustion engine (1) according to one of claims 5 to 9, characterized in that the jet orientation cap (17) borders on the flow guide wall (31).

11. Internal combustion engine (1) according to one of claims 5 to 10, characterized in that the jet orientation cap (17) and the injector sleeve (14) form a multi-part assembly unit or a one-part sleeve unit (E).

12. Internal combustion engine (1) according to one of claims 5 to 11, characterized in that the jet orientation cap (17) is pre-assembled on the injector sleeve (14) and is inserted together with the injector sleeve (14) into at least one receiving bore (15) of the cylinder head (3).

13. Internal combustion engine (1) according to one of claims 5 to 12, characterized in that the jet orientation cap (17) directly borders on at least one - preferably lower - cooling chamber (8) and is wetted by coolant, preferably flowing around it.

14. Internal combustion engine (1) according to one of claims 5 to 13, characterized in that the injector sleeve (14) is designed as a wet sleeve and directly borders on at least one - preferably upper - cooling chamber (9) and is wetted by coolant, preferably flowing around it.

15. Internal combustion engine (1) according to one of claims 5 to 14, characterized in that at least one cooling chamber - preferably the upper cooling chamber (9) is fluidly connected to a cylinder block cooling chamber in the cylinder block (4) via a coolant transfer channel (24) in the fire deck (7), wherein a bypass channel (25) branching off from the coolant transfer channel (24) leads directly to the jet orientation cap (17).

16. Internal combustion engine (1) according to one of claims 5 to 15, characterized in that at least one sealing element (19, 19a) is arranged between the jet orientation cap (17) and the injector sleeve (14) and / or between a first sleeve part (14a) and a second sleeve part (14b).

17. Internal combustion engine (1) according to claim 16, characterized in that the jet orientation cap (17) and / or the first sleeve part (14a) has at least one first annular groove (20, 20a) in the region of an outer circumferential surface for partially receiving the at least one sealing element (19, 19a) - preferably designed as an O-ring.

18. Internal combustion engine (1) according to claim 16 or 17, characterized in that an inner circumferential surface of the injector sleeve (14) in the region of the sealing element (19) has a second annular groove (21) for partially receiving the sealing element (19).

19. Internal combustion engine (1) according to claim 16 or 17, characterized in that an inner circumferential surface of the second sleeve part (14b) in the region of the sealing element (19a) has a second annular groove (21a) for partially receiving the first sleeve part (14a).

20. Internal combustion engine (1) according to one of claims 5 to 19, characterized in that the jet orientation cap (17) or the injector sleeve (14) has a - preferably conical - annular shoulder (22), wherein the shoulder (22) rests - preferably in a gas-tight manner - on an annular support surface (23) of the cylinder head (3) corresponding to the shoulder (22), wherein the support surface (23) is preferably formed at least partially by the flow guide wall (31).

21. Internal combustion engine (1) according to one of claims 5 to 20, characterized in that the injector sleeve (14) is connected to the cylinder head (3) in a force-locking and / or form-locking manner, preferably by a screw connection, a press connection and / or an adhesive connection.

22. Internal combustion engine (1) according to one of claims 5 to 21, characterized in that the jet orientation cap (17) is correctly positioned in the cylinder head (3) via a positioning element (18) preferably formed by a pin.

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