CN220646080U

CN220646080U - Cylinder head and internal combustion engine with precombustion chamber

Info

Publication number: CN220646080U
Application number: CN202321373157.XU
Authority: CN
Inventors: 雷蒙德·登辛
Original assignee: Fev Group Co ltd
Current assignee: Fev Group Co ltd
Priority date: 2022-06-02
Filing date: 2023-06-01
Publication date: 2024-03-22
Anticipated expiration: 2033-06-01
Also published as: DE102023114112A1; DE102022113980A1

Abstract

The utility model relates to a cylinder head (10) and an internal combustion engine having the same, the cylinder head comprising a spark plug hole (31) for receiving and securing a spark plug (30) or a glow plug, and the cylinder head (10) comprising a receiving portion (21) for receiving and securing a prechamber cover (20).

Description

Cylinder head and internal combustion engine with precombustion chamber

Technical Field

The present utility model relates to an internal combustion engine and a cylinder head.

Background

For the combustion of lean combustible gas mixtures, in particular in otto engines, it is known to use a prechamber in which the combustible gas mixture is ignited, so that the combustion can then propagate into the main combustion chamber. For this purpose, receptacles are known, such as spark plug adapters, which are accommodated in the cylinder head and contain the prechamber. As prior art, DE 461 335c, DE 472 993c and DE 844 092c disclose a prechamber diesel engine or an injection internal combustion engine with a prechamber. The disadvantage of the spark plug adapter concept is, in particular, that the spark plug adapter is a separate component which must be produced in an expensive manner.

Disclosure of Invention

It is an object of the present utility model to provide an improved prechamber system, in particular for otto engines, which prechamber system is low-cost in terms of manufacture and advantageous in terms of thermal dissipation of combustion heat into the cylinder head.

The object is achieved by a cylinder head and an internal combustion engine having a cylinder head according to the utility model. Preferred embodiments are described herein.

The cylinder head includes a spark plug hole for receiving and securing a spark plug or glow plug. Furthermore, the cylinder head comprises a receiving portion (such as in particular a hole) for receiving and fastening the prechamber cover. Conventionally, in particular, a prechamber tip has been used, which is fitted as a sleeve onto the tip of the spark plug and welded there. The advantages described below in the preferred embodiment result from the use of a prechamber cover rather than a conventional prechamber tip attached to a spark plug. The term "prechamber cover" particularly denotes the part which is functionally between the spark plug tip that generates the ignition spark and the (main) combustion chamber and which causes a gas-permeable delimitation and thus defines the prechamber. The prechamber is thus arranged in particular between the prechamber cover and the spark plug and/or the injector. Preferably, there is a spacing from the spark plug (and or injector) and the prechamber cover as a spatial separation. The spacing may be devoid of means for locating the prechamber. The receptacle for the prechamber cover can in particular be a hole.

The main field of use of the utility model is otto engines, since there is a need for improvement towards lower fuel consumption, which can be caused by low-rich combustion gases. In principle, the advantages can also be applied to diesel engines. Thus, the term "spark plug hole" as used in the sense of the present utility model is to be understood in a broad sense such that for this purpose only a hole is indicated in which a glow plug can also be accommodated. Other structural differences in these engine types are not considered herein.

In particular, the fastening of the prechamber cover in the receptacle can be independent of the fastening of the spark plug in the spark plug hole. In other words, the two parts each comprise a fastening means, such as in particular a screw-on device, preferably having an external thread, by means of which the screw-on device is screwed (directly) into the cylinder head and one of the parts can be mounted or removed independently of the second part. Thus, due to the shorter tolerance chain, not only is accurate positioning of the spark plug in the prechamber feasible, but also accurate positioning of the prechamber cover relative to the combustion chamber.

Furthermore, the cylinder head may preferably comprise an injector bore for receiving an injector. An active prechamber is thus obtained. Structurally, the spark plug hole may also be a hole for receiving a common carrier of the spark plug and the injector. Very precise (axial) positioning of the injectors is very important, since a plurality of injectors are used accordingly in a multi-cylinder engine. For the same reason, an accurate angular orientation is required. The injector branches laterally from the rigid distributor and the axial positioning of the injector is important in order to keep the gap size and the seal size small in the connection there.

It is particularly advantageous if the prechamber can be introduced into the cylinder head from the combustion chamber side. Thus, accurate positioning of the prechamber cover relative to the combustion chamber is possible. Thus, the diameter of the prechamber cover can also be larger than, for example, the spark plug diameter, which improves the structural frame conditions for the passage of combustible gas in the prechamber cover.

Alternatively or additionally, the prechamber cover may be screwable with the cylinder head. Thus, the fastening and/or azimuthal positioning of the prechamber cover is independent of the fastening of other components, such as in particular the spark plug.

A stop may also be provided, preferably on the cylinder head for the prechamber cover, for positioning the prechamber cover axially inside the cylinder head.

In particular, a stop is advantageously provided for the axial positioning of the spark plug and is independent of the stop of the prechamber cover. This is an alternative expression for the aforementioned construction.

The application of the inventive subject matter in engines according to the otto principle results in a major improvement, since the prechamber system is mainly used in engines according to the diesel principle due to load demands, firmness demands and/or temperature demands (curves). In particular, the utility model is used in otto engines with extremely lean-burn fuel mixtures. It is known that reliable ignition is difficult to achieve in conventional spark plug systems.

Furthermore, the internal combustion engine can have a prechamber cover which can be screwed into the cylinder head on the combustion chamber side and which comprises a plurality of spanner surfaces on the radially outer side for fastening the prechamber cover. In particular the number of wrench faces is the same as the number of ports of the prechamber cover connecting the prechamber and the (main) combustion chamber. In particular, the number of wrench surfaces is the same as the number of openings of the boundary between the prechamber and the combustion chamber. Alternatively or additionally, the through openings of the prechamber cover are oriented at an angle to the central axis of the prechamber cover, which aids in the uniform distribution of the combustible gas in the main combustion chamber.

The prechamber cover and the spark plug may be arranged on opposite sides of the prechamber and the prechamber is partly delimited by the material of the cylinder head. It has also been shown that the prechamber cover and the spark plug are formed as separate parts and that, because the cylinder head delimits the prechamber directly, a better temperature conduction can be achieved in this way, which is sufficient without heat conduction through other materials or components.

Drawings

Hereinafter, preferred embodiments of the present utility model are exemplarily described with reference to the accompanying drawings. The drawings show:

FIGS. 1 and 2 illustrate prior art embodiments;

FIG. 3 shows a section through the cylinder head without the spark plug or injector being installed;

FIG. 4 shows the view of FIG. 3 with the spark plug and injector installed and also schematically showing the cooling holes; and

fig. 5 shows a perspective detail view of the prechamber.

Detailed Description

Fig. 1 and 2 show a conventional spark plug adapter 5, which is shown in fig. 1 in section A-A of fig. 2. The spark plug adapter 5 comprises a carrier body which is inserted into a receptacle of the cylinder head and is sealed with respect to the cylinder head and comprises screw bores 6 in order to be able to be screwed with the cylinder head. It can be seen in fig. 1 that the carrier is composed of two components, namely an upper body comprising the injector 40 and the receptacle for the spark plug 30, and a lower sleeve-like section defining the prechamber 16 and comprising a number of smaller openings relative to the combustion chamber of the engine. The two components are made of high temperature resistant steel and welded to each other.

The inventive embodiments of fig. 3 and 4 differ therefrom. It is therefore shown that the spark plug 30 and the injector 40 are fitted directly into the cylinder head 10, as is in particular (see spark plug 30) screwed there. Thus, no adapter or carrier is used for the component. This results in a cost saving in the first place, since structurally complex (carrier) parts are dispensed with. In addition, the positioning of the spark plug 30 and the injector 40 is improved. This results from a simpler tolerance chain, since the assembly tolerances of the spark plug 30 and the injector 40 are in the prior art directly related to the production and assembly tolerances of the spark plug adapter 5, respectively. Depending in particular on the positioning relative to the prechamber 16 in the spark plug 30, a common distributor (not shown) is required for the injectors 40 in multi-cylinder engines, which connects the individual injectors, and in order not to have an impermissible gap size when connecting the injectors to the distributor, the precise positioning of the injectors in the cylinder head 10 is of great importance. It is furthermore evident that the conventional spark plug adapter 5 is structurally extremely complex and additionally sealed with respect to the cylinder head 10, so that corresponding advantages result from the elimination of the spark plug adapter.

The prechamber volume can thus also be reduced. In principle, a small volume of the prechamber 16 is advantageous, such as for example less than 2.5% of the volume of the (main) combustion chamber. However, cooling of the prechamber 16 is also necessary and its structural design is difficult when using the plug adapter 5, so that a larger volume of the prechamber 16 results from the requirements. The prechamber surface is also partly directly identical to the cylinder head 10, so that heat conduction through the different components, which is associated with contact resistance at the material boundary, is avoided in these places.

Fig. 4 shows a stop 12 of the cylinder head, on which the circumferential edge of the prechamber cover 20 is supported. In an alternative embodiment, the section protruding upwards from the edge can become very short, so that this is just enough for the thread of the screw-on device and so that the share of the head surface on the prechamber 16 increases.

Fig. 4 also schematically shows cooling channels 14, which are preferably arranged circumferentially around the individual components. Preferably, the cooling channel is formed in a sealed manner adjacent to the prechamber 16. Since in the prior art the spark plug adapter 5 has a significant position requirement, by eliminating the spark plug adapter a larger volume of the cylinder head is obtained, which volume can be used for the coolant channel or the oil channel.

Fig. 5 shows prechamber cover 20 in perspective. A hexagonal profile is molded onto the lower section that protrudes into the combustion chamber 11, said hexagonal profile serving as a tool active surface 22. Furthermore, six openings 24 for combustible gas are likewise provided, which are associated with the tool active surface 22. Thus, although tool active surface 22 is slightly reduced in size, it is possible to uniformly output the combustible gas from prechamber cover 20 in six directions.

The above describes an active prechamber system, in which the combustion medium is introduced into the prechamber 16 by means of an injector 40. Alternatively, the utility model may also be used in passive prechamber systems, wherein injectors are not used. Therefore, the ejector 40 is eliminated as the only difference from the foregoing embodiment.

Claims

1. A cylinder head (10) has a spark plug hole (31) for receiving and securing a spark plug (30) or a glow plug,

characterized in that the cylinder head (10) comprises a receiving portion (21) for receiving and securing the prechamber cover (20).

2. The cylinder head (10) according to claim 1,

characterized in that the fastening of the prechamber cover (20) in the receptacle (21) is independent of the fastening of the spark plug (30) in the spark plug hole (31).

3. The cylinder head (10) according to claim 1 or 2,

characterized in that the cylinder head (10) comprises an injector bore (41) for receiving an injector (40), or the spark plug bore (31) is a common bore for receiving the spark plug (30) and the injector (40) by means of a common carrier.

4. The cylinder head (10) according to claim 1 or 2,

characterized in that the prechamber cover (20) can be introduced into the cylinder head (10) from the combustion chamber side (11).

5. The cylinder head (10) according to claim 1 or 2,

characterized in that the prechamber cover (20) can be screwed to the cylinder head (10).

6. The cylinder head (10) according to claim 1 or 2,

characterized in that a stop (12) for a prechamber cover (20) is provided on the cylinder head (10) for axially positioning the prechamber cover (20) in the cylinder head (10).

7. The cylinder head (10) according to claim 6,

characterized in that a stop (34) for axially positioning the spark plug (30) is provided on the cylinder head (10), and that the stop (34) for axially positioning the spark plug (30) is independent of and/or independent of the stop (12) for the prechamber cover (20).

8. An internal combustion engine having a cylinder head (10) according to any one of claims 1 to 7,

wherein in particular the prechamber cover (20) can be screwed into the cylinder head (10) on the combustion chamber side and comprises a plurality of key surfaces (22) on the radially outer side for fastening the prechamber cover (20), and in particular the number of key surfaces (22) is the same as the number of openings (24) of the boundary between the prechamber (16) and the combustion chamber (11).

9. An internal combustion engine according to claim 8,

wherein the prechamber cover (20) and the spark plug (30) are arranged on opposite sides of the prechamber (16) and the prechamber is partially delimited by the cylinder head (10).