CYLINDER HEAD FOR AN ENGINE

Description

[0001] The present invention relates to a cylinder head for an internal combustion engine, in particular for a hydrogen-powered internal combustion engine.

[0002] Cylinder heads close off the combustion chamber of internal combustion engines at the end opposite the piston. The cylinder heads contain the intake ports, also called intake ports, and the exhaust ports for the gas exchange processes in the combustion chamber of the internal combustion engine. The mixture formation of fuel and intake air can generally take place in the intake manifold or in the cylinder. In both cases, the fuel is injected via injectors, which are mounted on the cylinder head.

[0003] From US patent 2014 / 021272 A1, a cylinder head arrangement is known which has an injector that is directly fluidically connected to an inlet channel of the cylinder head via an injection tube.

[0004] A cylinder head arrangement is known from EP 0 915 248 A1. The outlet of an injector and an inlet port of the cylinder head are directly fluidically connected via an injection pipe.

[0005] From WO 2015 067 550 A1, a cylinder head with a combustion chamber-side fire deck and an injector sleeve detachably connected to the cylinder head for receiving an injection device is known. The injector sleeve is screwed to the fire deck at a first end on the fire deck side via a first screw connection and has, in the region of the first end, at least a radially projecting first bearing area with a first bearing surface facing the fire deck, which rests on a first counter surface formed by the cylinder head.

[0006] From DE 11 2017 001 678 T5, a cylinder head is known which has a fuel injection device with an injection port. The cylinder head includes a mounting hole into which a sleeve-shaped plastic cap is inserted, so that a through-hole, through which the fuel injection device extends, opens into the combustion chamber of an internal combustion engine.

[0007] Starting from this premise, the present invention aims to provide a cylinder head for an internal combustion engine that is easy to manufacture and assemble.

[0008] The underlying problem is solved by a cylinder head for an internal combustion engine, in particular for a hydrogen-powered internal combustion engine, wherein the cylinder head comprises: a cylinder head assembly having an intake port and a fuel inlet opening, the fuel inlet opening opening into the intake port, an injector holder detachably connected to the cylinder head assembly and having an injector receiving bore, an injector received in the injector receiving bore and clamped against the injector holder by means of clamping means, and a tubular plug piece arranged between the injector holder and the cylinder head assembly such that a discharge opening of the injector and the fuel inlet opening of the cylinder head assembly are fluidically connected to each other via the plug piece.

[0009] The cylinder head according to the invention has the advantage that the injector can be pre-assembled in the injector holder. Furthermore, the requirements for the machining tolerances of the connection dimensions between the cylinder head assembly and the injector holder can be kept low, since these can be compensated for by the tubular connector. The cylinder head according to the invention is therefore easy to manufacture and ensures easy assembly.

[0010] In one possible embodiment of the cylinder head, the injector holder can have a fuel transfer opening, with the injector receiving bore opening into the fuel transfer opening. The tubular connector can be arranged between the injector holder and the cylinder head assembly such that the injector's discharge port and the cylinder head assembly's fuel inlet port are fluidically connected via the fuel transfer opening and the connector.

[0011] In another possible embodiment, a tubular spring element can be provided, positioned between the injector holder and the connector such that the connector is resiliently supported on the injector holder in the axial direction with respect to a longitudinal axis of the connector. The connector can be in contact with the cylinder head assembly at one end and with the tubular spring element at the opposite end. The spring element allows for a further reduction in the required machining tolerances of the connection dimensions between the cylinder head assembly and the injector holder. Furthermore, the spring element prevents axial displacement of the connector due to pressure fluctuations.

[0012] Alternatively or in combination, a tubular spring element can be provided, which is arranged between the plug-in piece and the cylinder head assembly, so that the plug-in piece is resiliently supported on the injector holder. The plug-in piece can be in contact with the injector holder at one end and with the tubular spring element at the opposite end.

[0013] In another possible embodiment, the injector holder can have a receptacle for the plug in which the plug is inserted. Alternatively, or in combination, the cylinder head assembly can have a receptacle for the plug in which the plug is inserted.

[0014] In another possible embodiment, the injector holder can include a pressure accumulator that is fluidically connectable to a fuel source and fluidically connected to the injector.

[0015] It is also possible for the injector holder to comprise multiple injector mounting bores, each housing an injector. Alternatively, or in combination, the injector holder can include a pressure accumulator that is fluidically connected to a fuel source and fluidically connected to each injector. The pressure accumulator can extend through the injector holder as a cylindrical buffer bore. This buffer bore can be cast into the injector holder or subsequently machined into it.

[0016] The buffer bore can be closed at at least one end with a sealing element. If the cylindrical buffer bore is designed as a blind hole, it can be closed at one end with a first sealing element and at the other end by the bottom of the blind hole. If the cylindrical buffer bore is designed as a through hole, it can be closed at one end with a first sealing element and at the other end with a second sealing element.

[0017] The bore of the buffer can be arranged transversely, particularly skew, to each longitudinal axis of the injector receiving bores. It is conceivable that, in a projection, the bore of the buffer and the respective longitudinal axes of the injector receiving bores form an angle of 90°.

[0018] In one possible embodiment, the fuel inlet opening can open into the intake manifold via a tubular injection tube. The injection tube can be connected to the cylinder head assembly, in particular by screwing, gluing, or pressing it in.

[0019] Furthermore, the cylinder head arrangement can comprise a base element and an intake manifold, with the intake channel being formed at least partially by the base element and the intake manifold.

[0020] An exemplary embodiment is explained below with reference to the figures. This shows: Figure 1 shows a perspective view of a cylinder head according to the invention for a 6-cylinder internal combustion engine, Figure 2 shows a detail of a side view of the cylinder head made of Figure 1 Figure 3 shows a sectional view of the cylinder head. Figure 1 along the section plane III-III in Figure 2 , and Figure 4, a detailed view of the Figure 3 .

[0021] In the Figures 1 to 4 Figure 1, which is described below together, shows a cylinder head according to the invention for a 6-cylinder internal combustion engine. The cylinder head comprises a cylinder head assembly 1 with a base element 2, an intake manifold 3 and a valve train cover 4.

[0022] The base element 2 has a flame deck 6, which can be used to close off a combustion chamber (not shown) of the internal combustion engine. The base element 2 is made of a cast material. An inlet channel 7 is arranged in the base element 2, in particular cast into it. The inlet channel 7 penetrates the flame deck 6. The combustion chamber inlet 8 thus formed in the flame deck 6 can be selectively closed or opened by an inlet valve arrangement 9, in a manner known to those skilled in the art. An outlet channel 5 is arranged in the base element 2, in particular cast into it. The outlet channel 5 penetrates the flame deck 6. The combustion chamber outlet 5 thus formed in the flame deck 6 can be selectively closed or opened by an outlet valve arrangement, in a manner known to those skilled in the art.

[0023] The intake manifold 3 is connected to the base element 2 via connecting means 10. The intake manifold 3 also includes an inlet port 11, which together with the inlet port 7 of the base element 2 forms an intake port 12. The intake port 12 fluidically connects the combustion chamber inlet 8 to an intake air source, for example, a filter element, a compressor, or a turbocharger. In this respect, the base element 2 and the intake manifold 3 can be described as part of the cylinder head assembly.

[0024] The cylinder head assembly 1 has a fuel inlet opening 13. In the present case, the intake manifold 3 has the fuel inlet opening 13, although it is equally conceivable that the fuel inlet opening 13 is formed in the base element 2.

[0025] The fuel inlet opening 13 opens into the intake port 12 via an injection tube 14. In this case, the injection tube 14 is screwed into an internal thread integrated into the fuel inlet opening 13. However, any other detachable or permanent connection is also conceivable, whereby the injection tube 14 could, for example, be bonded to the cylinder head assembly 1 or pressed into the fuel inlet opening 13. Sealing materials (not shown) are provided between the injection tube 14 and the cylinder head assembly 1. Alternatively, a metal-to-metal sealing connection can exist between the injection tube 14 and the cylinder head assembly 1.

[0026] The injection tube 14 comprises a straight channel 15 that fluidically connects the fuel inlet opening 13 with an outlet opening 16 of the injection tube 14. The channel 15 extends along a longitudinal axis of the injection tube 14. This allows the fuel introduced via the fuel inlet opening 13 to enter closer to the combustion chamber inlet 8, resulting in advantageous mixture formation and cooling of the base element 2 in the region of the combustion chamber inlet 8. It is also conceivable that the injection tube 14 has a shape other than straight, and in particular is curved or S-shaped.

[0027] An injector holder 17 is detachably attached to the cylinder head assembly 1. In this case, the injector holder 17 is bolted to the intake manifold 3 via connecting elements 18, 18'. It is also conceivable that the injector holder 17 is bolted to the intake manifold 3 via connecting elements 18 and to the base element 2 via connecting elements 18'. Furthermore, it is conceivable that the injector holder 17 is detachably connected to at least one of the base element 2, the intake manifold 3, the valve train cover 4, and the exhaust pipe 5 via connecting elements.

[0028] The injector holder 17 comprises several injector receiving bores 19. In this case, the injector holder 17 comprises six injector receiving bores 19, corresponding to the number of cylinders of the internal combustion engine, but this number is not limited to six. Each injector receiving bore 19 accommodates an injector 22. The injectors 22 are clamped to the injector holder 17 by means of clamping devices 24. In this case, the clamping devices 24 are designed as clamping jaws. The injectors 22 have an electrical connection 23, via which they can be connected to a control unit (not shown). The injectors 22 can be controlled via the control unit.

[0029] The injector receiving bores 19 are fluidically connected to each other via a buffer bore 20. The buffer bore 20 serves as a common pressure reservoir for the injector receiving bores 19. In this case, the buffer bore 20 is designed as a through bore. At opposite ends of the buffer bore 20, it is sealed by a sealing element 21, 21'. The buffer bore 20 can be fluidically connected to a fuel source, for example a fuel pump, via lines not visible in the figures, and can be pressurized by it. It is conceivable that a connection to the line to the fuel source is provided instead of one of the sealing elements 21, 21'.

[0030] The bore of the buffer bore 20 is oriented at an angle to the respective longitudinal axes of the injector receiving bores 19, such that in a projection, the bore of the buffer bore 20 and the respective longitudinal axes of the injector receiving bores 19 form an angle of 90°. The offset between the bore of the buffer bore 20 and the respective longitudinal axes of the injector receiving bores 19 is greater than the radius of the buffer bore 20. The buffer bore 20 intersects the injector receiving bores 19 with a partial segment.

[0031] The individual injectors 22 are each sealed against the corresponding injector receiving bores 19 by two sealing elements 25, 25'. The two sealing elements 25, 25' are arranged such that a sealed space 27 is formed between an inner wall 26 of the injector receiving bore 19 and the injector 22, which is fluidically connected to the buffer bore 20. In this case, the sealed space 27 is designed as an annular space surrounding the injector 22. The annular space intersects the buffer bore 20. The annular space thus transitions into the buffer bore 20, establishing a fluidic connection.

[0032] Commercially available injectors 22 can be used. In this case, the injectors 22 have a schematically depicted inlet 28 that opens into the sealed chamber 27 and / or the buffer bore 20. The injectors 22 also include a discharge port 29, which can also be referred to as a spray port, through which the injectors 22 can discharge fuel. The fuel is discharged via the discharge port 29 in the direction of a fuel transfer opening 30 of the injector holder 17. The fuel transfer opening 30 of the injector holder 17 connects to the injector receiving bore 19. In other words, the injector receiving bore 19 opens into the fuel transfer opening 30 of the injector holder 17. In this case, the fuel transfer opening 30 has a circular cross-section with a constant diameter, but is not limited to this.In principle, it is also conceivable that the discharge opening 29 of the injectors 22 is at least partially located within the fuel transfer opening 30.

[0033] The fuel transfer opening 30 is fluidically connected to the fuel inlet opening 13 via a plug 32. For this purpose, the plug 32 is inserted with its first end 34 into a plug receptacle 42 of the cylinder head assembly 1, which in this case is designed as a cylindrical bore. The first end 34 of the plug 32 is in contact with the cylinder head assembly 1 on the head side. In this case, the first end 34 of the plug 32 is in contact with the intake manifold 3 on the head side. A sealing element 39 is provided between the first end 34 of the plug 32 and an inner wall 43 of the plug receptacle 42. The sealing element 39 is designed as an O-ring in this case. However, it is also conceivable that the sealing element 39 is implemented as one or more sealing lips vulcanized onto the plug 32.

[0034] The second end 35 of the plug 32 engages in a plug receptacle 31 of the injector holder 17, which in this case is designed as a cylindrical bore. The second end 35 of the plug 32 is in contact with a spring element 40 at its head. The spring element 40 is arranged between the plug 32 and the injector holder 17. The spring element 40 is, for example, tubular or ring-shaped. Accordingly, the spring element 40 includes an opening, which in particular has a circular cross-section with a constant diameter. The spring element 40 can be made of a metallic material or a plastic. A sealing element 39' is provided between the second end 35 of the plug 32 and an inner wall 38 of the plug receptacle 31. The sealing element 39' is designed as an O-ring.However, it is also conceivable that the sealing element 39' is implemented as one or more sealing lips vulcanized onto the plug piece 32. In this context, it is noted that in the . Figures 3 and 4 The sealing element 39, 39' and the spring element 40 are not shown in section.

[0035] The plug piece 32 comprises a channel 33 that fluidically connects the fuel inlet opening 13 to the fuel transfer opening 30 via the spring element 40. The channel 33 includes a first conical end section 36 at one end and a second conical end section 37 at the opposite end. The first conical end section 36 and the second conical end section 37 are connected to each other via a cylindrical section.

[0036] The first conical end section 36 narrows towards an opening oriented towards the fuel inlet opening 13 and widens towards the cylindrical section of the channel 33. The opening of the first conical end section 36 and the fuel inlet opening 13 are directly adjacent to each other. The cross-section of the opening of the first conical end section 36 corresponds to the cross-section of the fuel inlet opening 13.

[0037] The second conical end section 37 widens towards an opening directed towards the tubular spring element 40 and narrows towards the cylindrical section of the channel 33. The cross-section of the opening of the second conical end section 37 corresponds to the cross-section of the fuel transfer opening 30 and / or the cross-section of the opening of the spring element 40. In this case, the fuel transfer opening 30 and the opening of the spring element 40 each have the same diameter.

[0038] The fuel transfer opening 30, the opening of the spring element 40 and the channel 33 of the plug piece 32 thus form a connecting channel 41, which fluidically connects the discharge opening 29 of the injector 22 with the fuel inlet opening 13.

[0039] The first end 34 and the second end 35 of the plug 32 have different diameters, thus ensuring a defined installation position according to the key-lock principle. The plug 32 can therefore only be inserted between the injector holder 17 and the cylinder head assembly 1 in such a way that the channel 33 is aligned as described above. Reference symbol list

[0040] 1 Cylinder head assembly 2 Base element 3 Intake manifold 4 Valve train cover 5 Exhaust pipe 6 Flame deck 7 Intake port 8 Combustion chamber inlet 9 Intake valve assembly 10 Connecting element 11 Intake port 12 Intake port 13 Fuel inlet opening 14 Injection tube 15 Port 16 Exhaust port 17 Injector holder 18, 18' Connecting element 19 Injector mounting bore 20 Buffer bore 21, 21' Sealing element 22 Injector 23 Connection 24 Clamping element 25, 25' Sealing element 26 Inner wall 27 Space 28 Inlet 29 Discharge port 30 Fuel transfer opening 31 Plug fitting receptacle 32 Plug fitting 33 Port 34 End 35 End 36 Conical end section 37 Conical end section 38Inner wall 39 , 39'Sealing element 40Spring element 41Connecting channel 42Plug receptacle 43Inner wall

Claims

1. Cylinder head for an internal combustion engine, in particular for a hydrogen-powered internal combustion engine, comprising: a cylinder head assembly which comprises a suction duct (12) and a fuel inlet aperture (13), wherein the fuel inlet aperture (13) opens into the suction duct (12), an injector holder (17) which is detachably connected to the cylinder head assembly and has an injector receiving bore (19), an injector (22) which is received in the injector receiving bore (19) and is braced with respect to the injector holder (17) by means of clamping means (24), characterized by a tubular plug-in piece (32) which is arranged between the injector holder (17) and the cylinder head assembly in such a way that a discharge opening (29) of the injector (22) and the fuel inlet aperture (13) of the cylinder head assembly are fluidically connected to each other via the plug-in piece (32).

2. Cylinder head according to Claim 1, characterized in that the injector holder (17) has a fuel transfer aperture (30), wherein the injector receiving bore (19) opens into the fuel transfer aperture (30).

3. Cylinder head according to Claim 2, characterized in that the tubular plug-in piece (32) is arranged between the injector holder (17) and the cylinder head assembly in such a way that the discharge opening (29) of the injector (22) and the fuel inlet aperture (13) of the cylinder head assembly are fluidically connected to each other via the fuel transfer aperture (30) and the plug-in piece (32).

4. Cylinder head according to one of Claims 1 to 3, characterized in that a tubular spring element (40) is provided, which is arranged between the injector holder (17) and the plug-in piece (32) in such a way that the plug-in piece (32) is supported on the injector holder (17) resiliently in the axial direction with regard to a longitudinal axis of the plug-in piece (32).

5. Cylinder head according to Claim 4, characterized in that the plug-in piece (32) is in contact at a first end (34) with the cylinder head assembly and at an opposite second end (35) with the tubular spring element (40).

6. Cylinder head according to one of Claims 1 to 3, characterized in that a tubular spring element (40) is provided, which is arranged between the plug-in piece (32) and the cylinder head assembly, such that the plug-in piece (32) is supported on the injector holder (17) resiliently in the axial direction with regard to a longitudinal axis of the plug-in piece (32).

7. Cylinder head according to Claim 6, characterized in that the plug-in piece (32) is in contact at a first end with the injector holder (17) and at an opposite second end with the tubular spring element (40).

8. Cylinder head according to one of Claims 1 to 7, characterized in that the injector holder (17) has a plug-in piece receptacle (31), in which the plug-in piece (32) is seated.

9. Cylinder head according to one of Claims 1 to 8, characterized in that the cylinder head assembly has a plug-in piece receptacle (42), in which the plug-in piece (32) is seated.

10. Cylinder head according to one of Claims 1 to 9, characterized in that the injector holder (17) comprises a pressure accumulator (20) which can be connected fluidically to a fuel source and is connected fluidically to the injector (22).

11. Cylinder head according to one of Claims 1 to 9, characterized in that the injector holder (17) comprises a plurality of injector receiving bores (19), in each of which an injector (22) is received, and in that the injector holder (17) comprises a pressure accumulator (20) which can be connected fluidically to a fuel source and is connected fluidically to the injectors.

12. Cylinder head according to Claim 11, characterized in that the pressure accumulator (20) extends as a cylindrical buffer bore (20) through the injector holder (17), wherein, in particular, the buffer bore (20) is closed at at least one end by way of a sealing element (21, 21').

13. Cylinder head according to one of Claims 1 to 12, characterized in that the fuel inlet aperture (13) opens into the suction duct (12) via a small tubular injection tube (14).

14. Cylinder head according to Claim 13, characterized in that the small injection tube (14) is connected to the cylinder head assembly, in particular by being screwed in, adhesively bonded or pressed in.

15. Cylinder head according to one of Claims 1 to 15, characterized in that the cylinder head assembly comprises a main element (2) and an intake manifold (3), wherein the suction duct (12) is formed at least partially by the main element (2) and the intake manifold (3).