Cylinder head for an internal combustion engine and an internal combustion engine with such a cylinder head

Description

[0001] The present invention relates to a cylinder head for an internal combustion engine having the features of the preamble of claim 1 and to an internal combustion engine having such a cylinder head.

[0002] Such a cylinder head is shown in WO 2016 / 169712 A1. The attachment element described therein is a silencer for reducing structure-borne noise emissions during gas injection.

[0003] WO 2017 / 089042 A1 shows a similar cylinder head, in which a gas line is provided with guide vanes on the outside to impart a swirl to the combustion air and / or the fuel gas.

[0004] The cylinder head of internal combustion engines closes off the combustion chambers on the side opposite the piston and typically includes the intake and exhaust ports as well as the valve train for the gas exchange processes in the engine. In engines with port fuel injection, fuel is injected into the intake port, so that the fuel mixes with the intake air there.

[0005] From EP 0 694 124 B1, an internal combustion engine with intake manifold injection is known, in which fuel is injected into the intake port via a tube.

[0006] At the end opening into the intake port, the tube includes an atomizing screen that atomizes the fuel flowing from the tube, thus improving mixture formation. This has the disadvantage that the atomizing screen can become clogged during continuous operation, impairing fuel supply. Furthermore, fuel can be retained by the atomizing screen within the tube, potentially leading to unwanted backfires, particularly when using hydrogen as fuel.

[0007] From US 2014 / 0 084 085 A1, an internal combustion engine with an injector is known, wherein the injector comprises a nozzle element and a mixing section.

[0008] Starting from this, the present invention is based on the objective of providing a cylinder head for an internal combustion engine and an internal combustion engine with such a cylinder head, which enables permanently favorable mixture formation in the intake channel.

[0009] To solve the problem, a cylinder head with the features of claim 1 is proposed.

[0010] The radially outward-facing air guide section creates a more turbulent flow in the intake air downstream of it, which improves the mixing of the intake air with the fuel injected into the intake port via the injection tube. Because of the air guide section's radially outward orientation, the injection tube is not blocked by the air guide section, preventing it from becoming clogged during operation or retaining fuel within the injection tube.

[0011] The intake port forms the final part of the engine's air intake system. It connects the intake manifold to the combustion chamber and is opened and closed by the intake valves.

[0012] The injector can function even without the injection tube. The injection tube shifts the point where the fuel enters the intake port flow from the port's boundary wall to the center of the port. Therefore, the injection tube must be considered separately from the injector components necessary for its overall function.

[0013] In one possible embodiment, the radial extent of the air guide section with respect to the tube core can be greater than the axial extent in the direction of the tube core.

[0014] The air guide section or air guide disk can be designed, in particular, as an annular shape. The air guide section or air guide disk can have an opening whose longitudinal axis is arranged coaxially with the tube liner. The opening in the air guide disk can have a diameter that is greater than or equal to the diameter of the injection port.

[0015] In a further embodiment, the attachment element can have a first connecting section by which the attachment element is arranged on the injection tube. The attachment element can have an internal thread that engages with an external thread of the injection tube. Alternatively, the attachment element can be pressed onto the injection tube, or the attachment element and the injection tube can be manufactured as a single piece.

[0016] The air duct section can extend radially outwards from the first connecting section with respect to the tube core. Alternatively, the air duct section can connect to the connecting section axially along the tube core and extend radially outwards with respect to the tube core.

[0017] An embodiment is possible in which the smallest cylindrical envelope of the first connecting section, whose cylinder axis is arranged coaxially to the tube core, has a smaller radius than the largest radial distance of the air duct section from the tube core.

[0018] In another possible embodiment, the injection tube can have an injection opening that opens into the inlet channel.

[0019] To solve the problem, an internal combustion engine is further proposed which includes a cylinder head in a previously described configuration.

[0020] The following sections explain possible embodiments of a cylinder head or an internal combustion engine according to the invention, respectively, with reference to the figure drawings.

[0021] This shows: Figure 1 is a schematic representation of a partial sectional view of an internal combustion engine with a first cylinder head according to the invention; Figure 2 is a side view of the attachment element made of Figure 1 Figure 3 shows a view of the attachment element. Figure 1 in the direction of arrow III in Figure 2 ; and Figure 4, a sectional view of the attachment element along section line IV-IV from Figure 3 .

[0022] In the Figures 1 to 4An internal combustion engine 1, which is described jointly below, is shown. The internal combustion engine 1 is operated, in particular, with hydrogen as fuel. The internal combustion engine 1 comprises a crankcase 2, which is connected to a cylinder head 5 according to the invention. The crankcase 2 comprises, in a known manner, a variable combustion chamber 3, which is delimited by a movable piston 4 and the cylinder head 5. The cylinder head 5 comprises a cylinder head assembly having a cylinder head base element 6 and a cylinder head cover (not shown), which are connected to each other.

[0023] The cylinder head base element 6 incorporates an intake port 7 and an exhaust port 10. An air-fuel mixture can be supplied to the combustion chamber 3 via the intake port 7. The intake port 7 is bounded by a wall 8 and includes a combustion chamber inlet opening 9, which opens towards the combustion chamber 3. The combustion chamber inlet opening 9 can be selectively opened or closed by an intake valve 12 in a known manner. For this purpose, the intake valve 12 comprises an intake valve head 13, which is arranged in a valve seat of the combustion chamber inlet opening 9 when the combustion chamber inlet opening 9 is to be closed, and an intake valve stem 14, which extends substantially cylindrically along a valve axis L12. The intake valve 12 can be moved along the valve axis L12 by a corresponding valve train located above the cylinder head base element 6.

[0024] The exhaust gases produced by the combustion of the air-fuel mixture in the combustion chamber 3 can flow out of the combustion chamber 3 via the exhaust channel 10. The exhaust channel 10 is bounded by a wall and includes a combustion chamber outlet opening 11, which opens towards the combustion chamber 3. The combustion chamber outlet opening 11 can be selectively opened or closed by an exhaust valve 15 in a known manner. For this purpose, the exhaust valve 15 comprises an exhaust valve disc 16, which is arranged in a valve seat of the combustion chamber outlet opening 11 when the combustion chamber outlet opening 11 is to be closed, and an exhaust valve stem 17, which extends substantially cylindrically along a valve axis L15. The exhaust valve 15 can be moved along the valve axis L15 by the valve train.

[0025] For the formation of the air-fuel mixture, fuel is injected into the intake port 7 via an injector 18, which is connected to the cylinder head assembly, in particular to the cylinder head base element 6, by means not shown. For this purpose, an outlet of the injector 18 is fluidically connected to an injection tube 19, which extends along a tubular liner L19 into the intake port 7. The injection tube 19 includes an injection port 20, which opens into the intake port 7. In this case, the injection tube 19 is angled and comprises a first straight end section on the injector 18 side and a second straight end section on the injection port 20 side, which are connected to each other by a curved section. The tubular liner L19 extends completely from one end of the injection tube 19 to the opposite end, with the tubular liner L19 being Figure 1For the sake of clarity, it is only shown in the area of ​​the second end section. It is also conceivable that the tube core takes on any other shape, for example, being completely straight or S-shaped.

[0026] On the injection tube, in the area of ​​the second end section, sits a first attachment element 21, which is located in the Figures 2 to 4The first attachment element 21 comprises an annular first connecting section 22, the inner contour of which is complementary to the outer contour of the injection tube 19. The first attachment element 21 is firmly connected to the injection tube 19. In this case, the first attachment element 21 is screwed onto the injection tube 19. For this purpose, the attachment element 21 comprises a cylindrical connecting section 22 into which an internal thread 25 is machined. The attachment element 21 sits with the connecting section 22 on the second end section of the injection tube 19, with the internal thread 25 engaging with a complementary external thread (not shown) of the injection tube 19.For screwing the attachment element 21 onto the connecting tube 19, the connecting section 22 has tool engagement surfaces 26 which are designed to be complementary to a screwing tool, for example an open-end wrench or similar.

[0027] However, it is also conceivable that the two parts are joined in another way, for example by soldering, gluing, or pressing. It is also fundamentally possible that the attachment element 21 and the injection tube 19 are manufactured as a single piece.

[0028] Along the tube core L19, an air guide section 30 connects to the connecting section 22. When the fourth attachment element 21 is mounted on the injection tube 19, the air guide section 23 comes into axial contact with the injection tube 19.

[0029] The air guide section 23 is designed as an air guide disk, the extent of which in the direction of the tube core L19 is smaller than its radial extent with respect to the tube core L19. In this case, the air guide section 23 is designed as an external cylindrical section, without being restricted to this shape, and has a larger outer diameter than the connecting section 22. In other words, the air guide section 23 extends beyond the connecting section 22 in the radial direction with respect to the tube core L19.

[0030] The air guide section 23 includes an opening 24, which is in particular cylindrical and has a diameter of [missing information]. The longitudinal axis of the opening 24 is arranged coaxially with the tube liner L19. The diameter of the opening 24 is greater than or equal to the diameter of the injection port 20, so that fuel can flow freely out of the injection tube 19.

[0031] The air guide section 23 locally reduces the effective cross-section of the inlet channel 7, so that turbulence occurs in the direction of flow of the aspirated air behind the air guide section 23, which promotes the formation of a mixture of aspirated air and injected fuel.

[0032] In this case, the attachment element 21 is arranged outside an imaginary straight cylinder, the base of which is described by the inlet valve head 13 and extends along the valve axis L12. This ensures that the fuel-air mixture is sufficiently mixed upon entering the combustion chamber 3.

[0033] Furthermore, due to the Venturi effect, the effective pressure is reduced immediately behind the air guide section 23, so that any remaining fuel in the injection tube 19 is drawn out of the injection tube 19 and no fuel or air-fuel mixture can flow back into the injection tube 19. This prevents unwanted back-ignition of fuel in the injection tube 19. Reference symbol list

[0034] 1 Internal combustion engine 2 Crankcase 3 Combustion chamber 4 Piston 5 Cylinder head 6 Cylinder head base element 7 Intake port 8 Wall 9 Combustion chamber inlet opening 10 Exhaust port 11 Combustion chamber outlet opening 12 Intake valve 13 Intake valve head 14 Intake valve stem 15 Exhaust valve 16 Exhaust valve head 17 Exhaust valve stem 18 Injector 19 Injection tube 20 Injection port 21 Attachment element 22 Connecting section 23 Air guide section 24 Through hole 25 Internal thread 26 Tool engagement surface L19 Tube core L12 Valve shaft L15 Valve shaft

Claims

1. Cylinder head for an internal combustion engine (1), comprising: a cylinder head assembly which has an inlet port (7), a small tubular injection tube (19) which extends along a tube core (L19) into the inlet port (7), and an attachment element (21) which is arranged on the small injection tube (19), characterized in that the cylinder head has an injector (18) connected to the cylinder head assembly, wherein the small injection tube (19) is connected fluidically to the injector (18), and in that the attachment element (21) has an air-guiding portion (23) - which extends radially outwards with regard to the tube core (L19) in such a way that a flow in the inlet port (7) is influenced by the air-guiding portion (23), - which is designed as an air-guiding disc, and - which has an aperture (24) arranged coaxially with respect to the tube core (L19).

2. Cylinder head according to Claim 1, characterized in that a radial extent of the air-guiding portion (23) with regard to the tube core (L19) is greater than an axial extent.

3. Cylinder head according to either of Claims 1 and 2, characterized in that the attachment element (21) has a first connecting portion (22), by way of which the attachment element (21) is arranged on the small injection tube (19), wherein the air-guiding portion (23) extends radially outwards from the first connecting portion (22) with regard to the tube core (L19).

4. Cylinder head according to Claim 3, characterized in that the smallest cylindrical envelope of the first connecting portion (22), the cylinder axis of which is arranged coaxially with respect to the tube core (L19), has a smaller radius than the greatest radial spacing of the air-guiding portion (23) from the tube core (L19).

5. Cylinder head according to one of Claims 1 to 4, characterized in that the small injection tube (19) has an injection opening (20) which opens into the inlet port (7).

6. Cylinder head according to Claim 1, characterized in that the air-guiding disc adjoins the first connecting portion (22) in the direction of the tube core (L19).

7. Cylinder head according to Claim 6, characterized in that the air-guiding disc has an aperture (24), the longitudinal axis of which is arranged coaxially with respect to the tube core (L19).

8. Cylinder head according to Claim 7, characterized in that the aperture (24) of the air-guiding disc has a diameter greater than or equal to a diameter of the injection opening (20).

9. Cylinder head according to one of Claims 1 to 8, characterized in that the attachment element (21) has an internal thread (25) which engages into an external thread of the small injection tube (19).

10. Internal combustion engine comprising: a cylinder head (5) according to one of Claims 1 to 9.