Cylinder head for an internal combustion engine, and internal combustion engine
The cylinder head with integrated injector tubes and dual coolant paths provides enhanced cooling and sealing for injectors, overcoming thermal and sealing issues in internal combustion engines.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- FRITZ WINTER EISENGIESSEREI GMBH & CO KG
- Filing Date
- 2026-01-05
- Publication Date
- 2026-07-16
AI Technical Summary
Conventional internal combustion engines suffer from inadequate cooling of injectors, leading to thermal issues and sealing problems in injector sleeves.
A cylinder head design with integrated injector receiving tubes and a dual coolant path system, where coolant flows twice around the injector, providing direct and effective cooling without the need for an adapter or sleeve, and incorporating a return channel to enhance flow dynamics.
This design achieves superior cooling efficiency, reduces thermal stress, and ensures a reliable seal, effectively addressing the cooling and sealing challenges of conventional systems.
Smart Images
Figure EP2026050065_16072026_PF_FP_ABST
Abstract
Description
[0001] Cylinder head for an internal combustion engine and internal combustion engine
[0002] The present invention relates to internal combustion engines. In particular, the present invention relates to internal combustion engines with injectors. Furthermore, the present invention relates in particular to cylinder heads for such internal combustion engines.
[0003] Internal combustion engines with injectors are available for both liquid fuels, such as diesel engines, and gaseous fuels, such as natural gas or hydrogen engines. The injectors are also known as injection nozzles or injection nozzles. In conventional direct injection engines, the injector sits in an injector sleeve, which is mounted in the cylinder head of the engine. The injector sleeve acts as an adapter between the injector and the cylinder head. Experience has shown that the cooling of the injectors in conventional internal combustion engines is not always satisfactory.
[0004] Therefore, it would be desirable to provide combustion engines or components of such combustion engines that enable improved cooling of injectors.
[0005] Exemplary embodiments of the invention comprise a cylinder head for an internal combustion engine, comprising: a casting for closing a combustion chamber of the internal combustion engine; a first cavity in the casting that allows coolant to be supplied to the cylinder head; a second cavity in the casting that is connected to the first cavity and forms part of a cooling jacket with respect to the combustion chamber; and an injector receiving tube shaped for receiving an injector and having a combustion chamber-side end region; wherein the injector receiving tube is cast integrally with the casting;and wherein the first cavity volume passes by a first area of the injector receiving tube to be cooled, and the second cavity volume passes by a second area of the injector receiving tube to be cooled, the second area to be cooled being closer to the combustion chamber-side end region of the injector receiving tube than the first area to be cooled. Exemplary embodiments of the invention enable particularly effective cooling of an injector that is inserted into the injector receiving tube.
[0006] By routing the coolant flow twice past the injector receiver tube, particularly effective, distributed cooling of the injector located within the tube can be achieved. Specifically, the first cavity, which supplies coolant to the cylinder head, allows for cooling with a comparatively cold and therefore highly effective coolant. The second cavity, which forms part of the cooling jacket for the combustion chamber, provides a space-saving secondary cooling element for the injector, integrated into the geometry of the combustion chamber cooling jacket.
[0007] By forming the injector housing tube as an integral part of the cast body, very direct cooling of the injector is possible, namely cooling through only the single material layer of the cast injector housing tube. Compared to earlier approaches, where the injector is inserted into the cylinder head using an injector sleeve, there are no different materials surrounding the injector. Adverse thermal effects resulting from the interaction of the two materials of the injector sleeve and the cylinder head can be avoided. Complex cooling measures of earlier approaches, such as cooling gaps in and around the injector sleeve for targeted coolant flow, can also be avoided. Likewise, sealing problems that the injector sleeves of such earlier designs exhibit under the thermal stresses of long-term operation can be avoided.Unlike previous designs using an injector sleeve, the cast injector mounting tube eliminates the need for special sealing measures against the coolant. This results in particularly effective cooling of the injector and a particularly good and long-lasting, reliable seal between the injector and the coolant.
[0008] The cylinder head features an injector receptacle tube shaped to accommodate an injector. This receptacle tube thus forms the injector seat. Accordingly, the injector can be inserted directly into the receptacle tube, i.e., without an adapter. The receptacle tube forms a complete enclosure of both the first and second combustion chambers, creating a complete seal. The terms injector and injection nozzle / injection nozzle are used synonymously here. Therefore, the receptacle tube can also be referred to as the injection nozzle receptacle tube or the injection nozzle receptacle tube, depending on whether liquid or gaseous fuel is used.
[0009] The cylinder head has a cast body to close off a combustion chamber. Within this cast body is a second cavity that forms part of the cooling jacket for the combustion chamber. The combustion chamber can be a cylinder of the internal combustion engine, and the cooling jacket can be arranged around the cylinder to cool it. It is understood that the internal combustion engine can have one cylinder, but it can also have several cylinders. The multiple cylinders then constitute multiple combustion chambers of the internal combustion engine, each with its own associated cooling jacket. Overall, it is understood that the elements / features of the cylinder head described above can be present multiple times, in particular for each cylinder of the internal combustion engine. There can be a first cavity, as described herein, a second cavity, as described herein, and an injector receiving tube, as described herein, for each cylinder.It is possible that the cooling jackets of the individual cylinders are interconnected.
[0010] According to a further embodiment, the cylinder head can be connected to a crankcase. In particular, the combustion chamber can be arranged between the crankcase and the cylinder head. In other words, the combustion chamber can be closed off on one side by the crankcase and on the other side by the cylinder head.
[0011] According to a further embodiment, the first cavity can be connected to a coolant supply line in the crankcase. In this way, "fresh" coolant can flow from the crankcase into the cylinder head and enter the first cavity in the cast body.
[0012] According to another embodiment, the cylinder head is designed to terminate one or more cylinders of the internal combustion engine. In other words, the internal combustion engine can have one or more cylinders, and the cylinder head can be designed as an integral casting to terminate all of the cylinders. The cylinder head can be designed to terminate 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders. In particular, the cylinder head can be designed to terminate any number of cylinders between 1 and 20. In exemplary embodiments, the cylinder head can be designed to terminate four to six cylinders of the internal combustion engine. The numerical values mentioned above mean that the internal combustion engine can have any number of cylinders between 1 and 20. The numerical values mentioned above for the number of cylinders also apply accordingly to the internal combustion engine as a whole.
[0013] According to another embodiment, an injector receiving tube is provided in the cast body of the cylinder head for each cylinder. Exactly one injector per cylinder can be provided for the internal combustion engine.
[0014] According to an alternative embodiment, several injector receiver tubes can be provided per cylinder. In particular, exactly two injector receiver tubes can be provided per cylinder. Accordingly, the internal combustion engine can have several injectors, in particular exactly two injectors, per cylinder.
[0015] According to another embodiment, the first and second cavities form a coolant path that flows from bottom to top through the first cavity and from top to bottom through the second cavity towards the combustion chamber. In such an arrangement, the connection between the first and second cavities is located at the top of the cylinder head. This enables top-down cooling of the combustion chamber, where the coolant flows from top to bottom in the cooling jacket surrounding the combustion chamber. Such top-down cooling can be particularly effective.
[0016] According to a further embodiment, the injector receiving tube is shaped to accommodate the injector without a sleeve. In other words, the injector receiving tube is shaped to accommodate the injector without the need for a sleeve or adapter between the injector receiving tube and the injector. The injector receiving tube forms a cast, direct injector seat. The injector receiving tube surrounds the inserted injector. It simultaneously forms a mechanical seat for the injector and a seal against the coolant in the first and second combustion chambers. According to a further embodiment, the injector receiving tube is arranged laterally with respect to the combustion chamber. In particular, the injector receiving tube can extend obliquely upwards through the cylinder head with respect to the combustion chamber.In such a lateral arrangement, the injector receiver tube is not aligned with the combustion chamber / cylinder. In other words, a longitudinal axis of the injector receiver tube can form an acute angle with a longitudinal axis of the combustion chamber. One can also say that the injector receiver tube extends obliquely upwards through the cylinder head from its combustion chamber-side end. This means that the open end of the injector receiver tube is offset upwards and laterally relative to its combustion chamber-side end. In an inline cylinder arrangement, this lateral offset means, in particular, that the direction of extension of the injector receiver tube is essentially orthogonal to the longitudinal direction of the cylinder arrangement.The open end of the injector receiver tube is the part of the tube through which the injector is inserted into and removed from the cylinder head. With a lateral arrangement of the injector receiver tube, the passage of the first and second combustion chambers past the tube can be achieved in a particularly space-saving manner.
[0017] According to a further embodiment, the cylinder head also features a return line between the second and first cavities in the vicinity of the injector housing tube. This return line allows already heated coolant from the second cavity to be fed back into the first cavity. While this mixing of heated coolant into the first cavity is energetically disadvantageous, it helps to generate increased flow around the injector housing tube and thus contributes to particularly effective cooling of the injector housing tube and the injector located within it.
[0018] According to a further embodiment, the return flow consists of exactly one return channel or several return channels from the second cavity to the first cavity. With multiple injector receiving tubes, exactly one return channel per injector receiving tube can be provided, or several return channels per injector receiving tube can be provided. In particular, the multiple return channels can be exactly two return channels from the second cavity to the first cavity. As described above, the return channel(s) is suitable for increasing the flow around the injector receiving tube or generating increased flow dynamics around the injector receiving tube.By providing exactly one or exactly two return channels, a particularly good compromise can be achieved between improved flow around the injector receiving tube and limiting the thermal disadvantages caused by returning already heated coolant to the first cavity volume.
[0019] The aforementioned return channel(s) can be cast. In other words, the aforementioned return channel(s) can be cavities created during the casting of the cylinder head. Since the cylinder head is already cast, providing cast return channels is a comparatively simple and therefore cost-effective solution.
[0020] It is also possible for the return channel(s) to be created through subsequent machining of the casting. Such subsequent machining, for example by drilling the return channel(s) into the casting, allows for more precise dimensioning, potentially better tailored to the cooling requirements. This subsequent machining can be performed through an opening created during casting, which is then sealed after machining. A hybrid solution combining casting and subsequent machining is also possible. For instance, the return channel(s) can be cast in their rough dimensions, and subsequent machining can ensure their precise dimensioning.
[0021] According to a further embodiment, the injector receiving tube has a wall thickness of at least 2 mm, in particular a wall thickness of between 2 mm and 50 mm, and more specifically a wall thickness of between 2 mm and 20 mm. A wall thickness within the specified range can be particularly well suited to providing an advantageous compromise between mechanical stability, good manufacturability, and effective heat conduction between the injector and the coolant. The injector receiving tube can have a wall thickness within the specified range at its thinnest point. It is also possible for the injector receiving tube to have a wall thickness within the specified range both in the first area to be cooled, past which the first cavity passes, and at its thinnest point in the second area to be cooled, past which the second cavity passes, and also, if present, at its thinnest point at one or more return channels.The wall thickness or the wall thickness profile can depend on the engine size of the internal combustion engine and / or on the cooling requirements of the injector in a specific application and / or on the available space and / or on other factors.
[0022] According to a further embodiment, the one or more return channels are located at a distance of between 2 mm and 50 mm, in particular between 2 mm and 20 mm, and further, in particular between 2 mm and 10 mm, from the inside of the injector receiving tube. These distances are suitable for promoting effective cooling of the injector in the area of the return channel(s). Again, the distance can depend on the engine size and / or the cooling requirements of the injector in a specific application and / or on the available space and / or other factors.
[0023] According to a further embodiment, the one return channel or the multiple return channels have a diameter greater than 1 mm, in particular a diameter greater than 2 mm. It is also possible for the one return channel or the multiple return channels to have a diameter between 1 mm and 30 mm, in particular between 2 mm and 20 mm, further in particular between 4 mm and 8 mm, and even further in particular between 5 mm and 7 mm. With these diameters, a particularly good compromise can be achieved between generating additional flow dynamics around the injector receiving tube and non-excessive recirculation of already heated coolant from the second cavity to the first cavity.
[0024] According to a further embodiment, the cylinder head is designed for a hydrogen combustion engine. In particular, the cylinder head can be designed for a hydrogen combustion engine with direct injection. The cylinder head described herein is particularly well suited for use in hydrogen combustion engines because the improved cooling of the injector effectively counteracts the problem of hydrogen embrittlement of the injector at high operating temperatures. According to a further embodiment, the cylinder head is designed for a hydrogen combustion engine with low-pressure injection at between 5 bar and 90 bar, in particular at between 5 bar and 60 bar.
[0025] According to another embodiment, the cylinder head is designed for a hydrogen combustion engine with high-pressure injection at between 200 bar and 400 bar, in particular at between 250 bar and 300 bar.
[0026] According to another embodiment, the cylinder head is designed for a diesel or natural gas combustion engine. The improved injector cooling can also be advantageously used in diesel and natural gas combustion engines.
[0027] Exemplary embodiments of the invention further comprise a combination of a cylinder head, as described in the preceding embodiments, and an injector, wherein the injector is inserted directly into the injector receiving tube of the casting. In other words, the injector is inserted into the injector receiving tube of the casting without an intermediate sleeve, adapter, or similar device. The additional features, modifications, and effects described above with reference to the cylinder head are applicable analogously to the combination of a cylinder head and an injector.
[0028] Exemplary embodiments of the invention further include an internal combustion engine comprising a cylinder head according to one of the preceding embodiments. The internal combustion engine can, in particular, be a hydrogen internal combustion engine. It is also possible for the internal combustion engine to be a diesel internal combustion engine or a natural gas internal combustion engine. The additional features, modifications, and effects described above with reference to the cylinder head are applicable analogously to the internal combustion engine comprising such a cylinder head.
[0029] According to another embodiment, the combustion engine is a hydrogen engine designed for direct injection. The hydrogen engine can be designed for low-pressure injection between 5 bar and 90 bar, particularly for low-pressure injection between 5 bar and 60 bar. The hydrogen engine can also be designed for high-pressure injection between 200 bar and 400 bar, particularly for high-pressure injection between 250 bar and 300 bar.
[0030] Further exemplary embodiments of the invention are described below with reference to the accompanying drawings.
[0031] Fig. 1 shows a cylinder block according to an exemplary embodiment of the invention in combination with a matching crankcase, wherein Fig. 1 is shown partly as a vertical sectional view and partly as a schematic arrangement of functional blocks.
[0032] Fig. 2 shows a casting core for the manufacture of the cylinder head of Fig. 1, wherein the casting core is shown in the same vertical sectional view as the cylinder head of Fig. 1.
[0033] Fig. 3 shows a horizontal section through the casting core of Fig. 2.
[0034] Fig. 1 shows a cylinder head 2 according to an exemplary embodiment of the invention in a vertical sectional view in conjunction with a matching crankcase 4, which is shown as a schematic arrangement of functional blocks.
[0035] Figure 1 shows a section of an internal combustion engine according to an exemplary embodiment of the invention, with Figure 1 showing a cylinder 44 of the internal combustion engine and its surrounding components. It is understood that the internal combustion engine can have several cylinders and surrounding components. In this case, the several identical component groups can, for example, be arranged in a row. With such a row arrangement, further section planes could be drawn through the internal combustion engine, resulting in an analogous representation as in Figure 1, with the further section planes being arranged parallel to the section plane shown in Figure 1, in front of and / or behind the plane of Figure 1.
[0036] The cylinder head 2 has a cast body 20, and the crankcase 4 has a crankcase cast body 40. A combustion chamber 50 of the cylinder 44 is closed off on one side by the cast body 20 of the cylinder head 2 and on the other side by the crankcase cast body 40 of the crankcase 4. The ignition and combustion of the fuel in the combustion chamber 50 causes a piston 48 located in the cylinder 44 to move, which in turn drives a connecting rod 52 and contributes to the movement of a crankshaft (not shown).
[0037] The cast body 20 of the cylinder head 2 of the exemplary embodiment shown in Fig. 1 has a receptacle for a spark plug 8. The spark plug 8 extends from an upper end region of the cylinder head 2 to the combustion chamber 50. The spark plug 8 ignites the fuel in the combustion chamber 50. It is understood that the receptacle for the spark plug 8 in the cast body 20, as well as the spark plug 8 itself, can be omitted in engine designs that do not require external ignition, such as diesel combustion engines.
[0038] The cylinder head 2 further comprises an injector receiving tube 26. The injector receiving tube 26 is an integral part of the casting 20. In other words, the injector receiving tube 26 is cast integrally with the rest of the casting 20. The injector receiving tube 26 is shaped such that an injector 6, hereinafter also referred to as an injection nozzle or injection nozzle 6, can be inserted into the injector receiving tube 26. In particular, the injector receiving tube 26 is shaped such that the injector 6 can be inserted into the injector receiving tube 26 without an interposed sleeve, adapter, or the like. The injector receiving tube 26 forms the injector seat for the injector 6. The injector receiving tube 26 forms a closed receiving area for the injector 6, i.e., an area that is closed off from the areas of the cylinder head 2 through which coolant flows during operation.Thus, the injector receiving tube 26 forms a tight separation between the injector 6 and the areas of the cylinder head 2 through which coolant flows.
[0039] The injector receiving tube 26 has a combustion chamber-side end section 28, which faces the combustion chamber 50 of the cylinder 44. From there, the injector 6 can inject or blow fuel into the combustion chamber 50 during operation. At its opposite end, the injector receiving tube 26 has an open end 30. The injector 6 can be inserted into and removed from the injector receiving tube 26 through this open end 30.
[0040] In the plane of Fig. 1, the injector receiving tube 26 extends upwards and to the right from the combustion chamber 50. In other words, the injector receiving tube 26 extends obliquely upwards through the cast body 20 of the cylinder head 2. The free end 30 of the injector receiving tube 26 is thus laterally offset outwards from the combustion chamber-side end region 28 of the injector receiving tube 26, or from the combustion chamber 50 of the cylinder 44. The injector receiving tube 26 is arranged at an acute angle to a longitudinal axis of the cylinder 44, which causes the free end 30 to be laterally offset outwards relative to the cylinder 44. One can also say that the injector receiving tube 26 is arranged laterally with respect to the combustion chamber 50.
[0041] The following describes the coolant flow through the cylinder head 2, as it occurs during operation of the internal combustion engine, in conjunction with the coolant supply and discharge in the crankcase 4.
[0042] The cast body 20 has a cavity system through which coolant flows during operation of the internal combustion engine. The parts of the cavity system shown in Fig. 1 are all interconnected. Some of these connections extend in the section plane shown in Fig. 1. Other connections link different areas of the cavity system in front of and / or behind this section plane. For example, the areas of the cavity system shown to the right of the center of the cast body 20 are connected to the areas of the cavity system shown to the left of the center of the cast body 20, both in front of and behind the spark plug 8. The description of the cavity system of the cast body 20 refers to different cavity volumes, each serving different purposes related to cooling and connection to the crankcase 4.Even though these hollow volumes are designated and described separately, it is understood that they are part of the cavity system of the cast body 20 and are connected to each other in such a way that the coolant can flow from one hollow volume to another hollow volume.
[0043] To further illustrate the cavity system of the casting 20, Fig. 2 shows a vertical section through a casting core 10, which can be used to cast the casting 20. The casting core 10 has a complementary shape to the casting 20. For further understanding, Fig. 3 shows a horizontal sectional view through the casting core 10 of Fig. 2 and the casting 20 cast around the casting core 10. The horizontal sectional view of Fig. 3 allows connections of the cavity system of the casting 20 to be seen in front of and behind the section plane of Figs. 1 and 2. The section plane of Fig. 3 is labeled AA in Fig. 2, and the section plane of Fig. 2 is labeled BB in Fig. 1.
[0044] The cylinder head 2, as shown in Fig. 1, has a first cavity 22 in the cast body 20. The first cavity 22 extends around a first cooling area 32 of the injector receiving tube 26, the first cooling area 32 of the injector receiving tube 26 being located near the open end 30 of the injector receiving tube 26. In the plane of Fig. 1, the first cavity 22 forms the rightmost area of the cavity system of the cast body 20. The first cavity 22 is connected to a coolant supply line 42 in the crankcase 4. Fresh, relatively cool coolant can thus enter the cavity system of the cast body 20 of the cylinder head 2 from the coolant supply line 42 of the crankcase 4 and flow around the injector receiving tube 26 in the first cooling area 32. The flow of water takes place in front of and behind the plane of Fig. 1.
[0045] The cylinder head 2 further comprises a second cavity 24 within the cavity system of the cast body 20. The first cavity 22 is connected to the second cavity 24, allowing coolant to flow from the first cavity 22 into the second cavity 24. The second cavity 24 distributes the coolant in a lower region of the cylinder head 2 and returns it to the crankcase 4. The second cavity 24 forms a first part of a cooling jacket for the cylinder 44 and is connected to a second part 46 of the cooling jacket located in the crankcase 40.
[0046] The cooling jacket is designed to cool the cylinder 44 or the combustion chamber 50 within the cylinder 44. The coolant in the second cavity 24 can cool the cylinder 44 from above, and the part 46 of the cooling jacket located in the crankcase can provide lateral cooling. The part 46 of the cooling jacket located in the crankcase can be arranged around the cylinder 50 in a hollow-cylinder shape, with the exact geometry being adapted to the arrangement of the other components in the crankcase 4. It is also possible for discrete cooling channels or cooling arms to be arranged around the cylinder 44. For example, discrete cooling channels can be arranged around the cylinder 44 between 4 and 6, together forming the part 46 of the cooling jacket located in the crankcase. Regardless of the specific design of the cooling jacket, the part 46 of the cooling jacket located in the crankcase is shown in Fig.1 schematically and symbolically represented as a simple volume which is connected to the second cavity volume 24 of the cylinder head 2.
[0047] The second cavity 24, in the fully assembled state of the internal combustion engine, is connected to the part 46 of the cooling jacket located in the crankcase. During operation, the second cavity 24 supplies the part 46 of the cooling jacket located in the crankcase with coolant from above. The coolant distribution function of the second cavity 24 is evident from the horizontal section through the second cavity 24 in Fig. 3. In the horizontal sectional view of Fig. 3, the second cavity 24 has a branched system of cooling zones arranged between an outer region of the casting 20 and ring-shaped inner regions of the casting 20. In the exemplary embodiment shown in Fig. 3, these ring-shaped inner regions of the casting form four receiving areas 12 for four valves assigned to the cylinder 44.
[0048] The cylinder 2 further comprises a return channel 36 in the cavity system of the cast body 20. The return channel 36 forms a connection with a comparatively small diameter from the second cavity 24 to the first cavity 22. The return channel 36 is connected to the second cavity 24 both in front of and behind the plane of Fig. 1, as can be seen in Fig. 3.
[0049] The second cavity 24 passes by a second cooling area 34 of the injector receiving tube 26, so that coolant in the second cavity 24 can flow around the injector receiving tube 26 and the injector 6 located therein in the second cooling area 34 of the injector receiving tube 26. In the exemplary embodiment of Fig. 1, the return channel 36 is located at this second cooling area 34 of the injector receiving tube 26. The second cooling area 34 of the injector receiving tube 26 is closer to the combustion chamber-side end area 28 of the injector receiving tube 26 than the first cooling area 32 of the injector receiving tube.
[0050] The coolant path through the cylinder head 2 of Fig. 1 is illustrated with the aid of the cast core 10, as shown in Fig. 2. In particular, the flow of the coolant through the cylinder head 2 is illustrated with flow arrows. For better clarity, the flow through the first cavity 22 is shown with wider arrows and the flow through the second cavity 24 with narrower arrows.
[0051] Coolant originating from the coolant supply line 42 of the crankcase enters the first cavity 22 of the cylinder head 2 and flows around the first area 32 of the injector receiving tube 26 to be cooled. Although the flow around the injector receiving tube 26 takes place both in front of and behind the section plane of Fig. 2, arrows at the location of the injector receiving tube 26 illustrate that the coolant path runs from bottom to top in the cylinder head 2 at that point. In the plane of Fig. 2, the coolant enters the second cavity 24 to the right of the area intended for the spark plug 8 and distributes itself there in various directions.
[0052] In the sectional plane of Fig. 2, the coolant in the second cavity 24 is distributed to the left and to the right. Coolant flowing to the left and to the right continues towards the crankcase 4. The coolant flowing to the left enters the part 46 of the cooling jacket located in the crankcase, which is shown schematically in Fig. 1. The coolant flowing to the right enters areas of the part 46 of the cooling jacket located in the crankcase that are in front of and / or behind the plane of the drawing. To illustrate this general principle, arrows representing the coolant flow to the right in Fig. 2 also point downwards, even if the subsequent areas of the part 46 of the cooling jacket located in the crankcase are in front of and / or behind the plane of the drawing.
[0053] In this right-hand area, the second cavity volume 24 passes by the second area 34 of the injector receiving tube 26 to be cooled. Again, the coolant flows past both in front of and behind the plane of Fig. 2. For easier illustration, arrows indicating the coolant flow through the area of the injector receiving tube 26 are shown.
[0054] A portion of the coolant flow surrounding the second cooling area 34 of the injector housing tube 26 does not flow into the cooling jacket section 46 located in the crankcase, but instead re-enters the first cavity 22 via the return channel 36. The fact that comparatively warmer coolant is mixed with the comparatively cooler coolant in the first cavity 22 via the return channel 36 is initially disadvantageous with regard to the coolant's heat absorption. However, the return channel 36 allows for a higher flow dynamic around the second cooling area 34 of the injector housing tube 26. This enables particularly effective cooling of the injector housing tube 26 and the injector 6.
[0055] In general, the double passing of the coolant flow over the injector receiving tube 26 and the injector 6 enables particularly effective cooling of the injector receiving tube 26 and the injector 6. This particularly effective cooling is further supported by the additional flow dynamics with the help of the return channel 36.
[0056] It is possible that all the coolant from the coolant supply line 42 of the crankcase 4 enters the cylinder head 2, flows through the first cavity 22 and the second cavity 24, and from there enters the part 46 of the cooling jacket located in the crankcase. The cylinder 44 is cooled according to the principle of top-down cooling. It is also possible that the coolant supply line 42 is connected to the part 46 of the cooling jacket located in the crankcase 4 in another way, or that the coolant supply line 42 itself is part of the cooling jacket. For example, in the plane of Fig. 1, a coolant flow can occur in the crankcase from right to left around the cylinder 44. The coolant path through the cylinder head 2, as described above, represents a secondary path to such a flow.
[0057] Water or another suitable coolant can be used.
[0058] Although the invention has been described with reference to exemplary embodiments, it is apparent to a person skilled in the art that various modifications can be made and equivalents used without departing from the scope of the invention. The invention is not intended to be limited by the specific embodiments described. Rather, it encompasses all embodiments covered by the appended claims.
Claims
M27304.1 Patent claims 1. Cylinder head (2) for an internal combustion engine, comprising: a cast body (20) for closing a combustion chamber (50) of the internal combustion engine; a first cavity volume (22) in the cast body (20) that allows coolant to be supplied to the cylinder head (2); a second cavity (24) in the cast body (20), which is connected to the first cavity (22) and forms part of a cooling jacket with respect to the combustion chamber (50); and an injector receiving tube (26) shaped to receive an injector (6) and having a combustion chamber-side end region (28); wherein the injector receiving tube (26) is cast integrally with the casting body (20); and wherein the first cavity volume (22) passes by a first cooling area (32) of the injector receiving tube (26) and the second cavity volume (24) passes by a second cooling area (34) of the injector receiving tube (26), wherein the second cooling area (34) is closer to the combustion chamber-side end area (28) of the injector receiving tube (26) than the first cooling area (32).
2. Cylinder head (2) according to claim 1, wherein the cylinder head (2) is connectable to a crankcase (4) and the first cavity volume (22) is connectable to a coolant supply line (42) in the crankcase (4).
3. Cylinder head (2) according to claim 1 or 2, wherein the cylinder head (2) is designed to terminate one or more cylinders of the internal combustion engine, and / or wherein one or more injector receiving tubes (26) are provided per cylinder (44).
4. Cylinder head (2) according to one of the preceding claims, wherein the first cavity volume (22) and the second cavity volume (24) form a coolant path which leads from bottom to top through the first cavity volume (22) and from top to bottom through the second cavity volume (24) in the direction of the combustion chamber (50).
5. Cylinder head (2) according to one of the preceding claims, wherein the injector receiving tube (26) is formed without a sleeve for receiving the injector (6).
6. Cylinder head (2) according to one of the preceding claims, wherein the injector receiving tube (26) is arranged laterally with respect to the combustion chamber (50), wherein the injector receiving tube (26) extends obliquely upwards through the cylinder head (2) in particular with respect to the combustion chamber (50).
7. Cylinder head (2) according to one of the preceding claims, further comprising: a conclusion between the second cavity volume (24) and the first cavity volume (22) in a vicinity of the injector receiving tube (26).
8. Cylinder head (2) according to claim 7, wherein the return consists of exactly one return channel (36) or several return channels from the second cavity volume (24) into the first cavity volume (22).
9. Cylinder head (2) according to one of the preceding claims, wherein the injector receiving tube (26) has a wall thickness of at least 2 mm, in particular a wall thickness of between 2 mm and 50 mm, and further in particular a wall thickness of between 2 mm and 20 mm, and / or wherein the exactly one return channel (36) or the multiple return channels has a distance of between 2 mm and 50 mm, in particular between 2 mm and 20 mm, and further in particular between 2 mm and 10 mm, from the inside of the injector receiving tube (26).
10. Cylinder head (2) according to claim 8 or 9, wherein the exactly one return channel (36) or the multiple return channels has / have a diameter of between 1 mm and 30 mm, in particular between 2 mm and 20 mm, and further in particular between 4 mm and 8 mm.
11. Cylinder head (2) according to one of the preceding claims, wherein the cylinder head (2) is designed for a hydrogen combustion engine, wherein the cylinder head is designed in particular for a hydrogen combustion engine with direct injection, wherein the cylinder head is further designed in particular for a hydrogen combustion engine with low-pressure injection at between 5 bar and 90 bar or for a hydrogen combustion engine with high-pressure injection at between 200 bar and 400 bar.
12. Cylinder head (2) according to one of claims 1 to 10, wherein the cylinder head (2) is designed for a diesel internal combustion engine or a natural gas internal combustion engine.
13. Combination of a cylinder head (2) according to one of the preceding claims and an injector (6), wherein the injector (6) is inserted directly into the injector receiving tube (26) of the cast body (20).
14. Internal combustion engine, in particular hydrogen engine, comprising a cylinder head (2) according to any one of claims 1 to 12.
15. Internal combustion engine according to claim 14, wherein the internal combustion engine is a hydrogen engine designed for direct injection, wherein the hydrogen engine is in particular designed for low-pressure injection at between 5 bar and 90 bar or for high-pressure injection at between 200 bar and 400 bar.