EP1942264B1 - Cylinder head for internal combustion engine and method to manufacture such cylinder head - Google Patents

Description

The invention relates to a cylinder head for an at least one cylinder having internal combustion engine having at least two charge exchange channels, namely at least one inlet channel for supplying the fresh air or the fresh mixture through at least one inlet opening in the at least one cylinder and at least one outlet channel for discharging the combustion gases through at least one outlet opening from the at least one cylinder.

Furthermore, the invention relates to a method for forming such a cylinder head.

Internal combustion engines usually have a cylinder head and a cylinder block.

The cylinder block has a corresponding number of cylinder bores for receiving the pistons or the cylinder tubes. The piston serves to transfer the gas forces generated by the combustion to the crankshaft. For this purpose, the piston is pivotally connected by means of a connecting rod with the crankshaft.

The cylinder head is usually used for receiving the combustion chamber side of the necessary for the change of charge control organs. For controlling the charge cycle, four-stroke engines use almost exclusively globe valves, which perform an oscillating lifting movement during operation of the internal combustion engine and in this way release and close the inlet and outlet openings. At least portions of the at least one inlet channel and the at least one outlet channel are integrated in the cylinder head. To actuate the valves, a valve actuator is required, which is also integrated in the cylinder head according to the prior art or is to be arranged in the vicinity of the valves and thus to the cylinder head.

To actuate a valve on the one hand a valve spring means is provided and on the other hand a camshaft used to open the valve against the biasing force of the valve spring means.

Frequently, overhead camshafts are used to operate overhead valves. An advantage of using overhead camshafts that in particular by the elimination of the bumper, the moving mass of the valve gear is reduced and the valve gear rigid d. H. less elastic. An overhead camshaft must also be accommodated in the cylinder head, which is usually done by arranging bearings or bearing blocks. In general, a camshaft is provided in each case for the outlet side and the inlet side.

The above explanations make it clear that the design of a cylinder head is decisively influenced and influenced by the elements or components required for the charge exchange, wherein both charge exchange channels for supplying the fresh air or the fresh mixture and for discharging the combustion gases must be provided, as well Valve gear for controlling the charge exchange, which includes the valves and the valve actuator is required.

It should be considered in particular that the required elements or components are not to be arranged in any way in or on the cylinder head, but usually a deliberately chosen arrangement and design of the inlet and outlet ports, but in particular the charge exchange channels is sought. The geometry of the charge exchange channels has a significant influence on the charge movement and thus on the mixture formation, especially in direct-injection internal combustion engines.

For example, the generation of a so-called tumbles or swirling flow can accelerate and assist mixture formation. A tumble is an air vortex about an imaginary axis which is parallel to the longitudinal axis of the crankshaft, as opposed to a swirl which is an air vortex whose axis is parallel to the piston or cylinder longitudinal axis.

The problem with regard to the very limited space in and on the cylinder head is reinforced by the fact that modern concepts for internal combustion engines four or five valves each Provide cylinder, which requires or requires a corresponding number of cylinder openings and charge exchange channels.

In spark-ignited internal combustion engines is also the required ignition device and beyond - especially in direct-injection internal combustion engines - to arrange the injector in the cylinder head. For this purpose, not only the required space must be provided. Rather, a particular arrangement of the ignition device or the injection device in the combustion chamber and each other is often sought - to optimize the mixture formation and the combustion process.

Thus, in the case of direct-injection internal combustion engines, an injection jet directed against the tumble can be effective in the event that the widest possible distribution of the fuel in the entire combustion chamber is sought. This requires a corresponding positioning of the injection nozzle.

If the internal combustion engine has liquid cooling, a plurality of coolant channels are generally provided in the cylinder head, which guide the coolant through the cylinder head. The arrangement of coolant channels leads to a very complex structure of Zylinderkoptkonstruktion. In this case, the mechanically and thermally highly stressed cylinder head is weakened by the introduction of the coolant channels on the one hand in its strength. On the other hand, the heat must not be directed to the cylinder head surface as in the air cooling, to be dissipated. It is endeavored to bring the coolant channels as close as possible to the thermally highly stressed areas of the cylinder head, i. near the combustion chamber.

Due to the much higher heat capacity of liquids compared to air can be dissipated with a liquid cooling much larger amounts of heat than is possible with air cooling. Taking into account that there is a trend towards small, supercharged engines, it can be seen that in practice liquid cooling is of much greater relevance than air cooling because the thermal load is greater with highly supercharged engines compared to conventional internal combustion engines.

The design of the liquid cooling of an internal combustion engine or the coolant jacket in the interior of a cylinder head as a system of a plurality of contiguous channels must be carried out taking into account aerodynamic aspects. Thus, care must be taken that a blistering is avoided by evaporation of coolant and venting of the cooling channels is ensured in the installed state of the internal combustion engine.

For connecting the cylinder head to the cylinder block bores are provided both in the cylinder head and in the cylinder block, wherein the cylinder block and the cylinder head are arranged for mounting in such a way to each other that the holes are aligned. Between the block and the head, a seal is usually provided in order to achieve a secure seal of the combustion chambers.

The cylinder head is connected to the cylinder block by means of threaded bolts, which are inserted and screwed into the bores of the cylinder head and the cylinder block. According to the state of the art, four bores or bolts are regularly arranged around a cylinder bore, with the bores lying between two cylinder bores, ie. the internal bores are assigned to two cylinder bores.

The individual requirements set out above, which are derived from the respective components and their function, interact with one another and can not be considered in isolation from one another, so that, for example, an optimization of the charge exchange channels with regard to mixture formation and charge exchange may not be possible. since this does not allow the arrangement of the cylinder head bores or bolts. Furthermore, it must be ensured that in particular the valves, the ignition device and the injection device are accessible for assembly purposes.

Since, according to the prior art, a cylinder head is generally a cast part, casting-technical aspects must also be taken into account in the design and manufacture. For example, the wall thickness of the individual walls formed in the cylinder head should vary only slightly and not abruptly. Sharp-edged transitions must be avoided and a minimum wall thickness must be maintained.

In the development of internal combustion engines is also increasingly seeking to realize a compact design as possible, which is why often reducing the distance from adjacent cylinder bores d. H. the desired cylinder longitudinal axes is sought. This development additionally exacerbates the problem of the very limited installation space or space available in and on the cylinder head.

The development towards more compact cylinder heads is also accelerated or driven by the fact that internal combustion engines are increasingly equipped with a charge. The charge is a suitable means to increase the capacity of an internal combustion engine with unchanged displacement or to reduce the displacement at the same power. The latter is also referred to as downsizing. At the same vehicle boundary conditions, the load spectrum can be shifted to higher loads, where the specific fuel consumption is lower. The reduction of the displacement, i. the downsizing of the internal combustion engine inevitably leads to more compact internal combustion engines or compact i. relatively small-volume cylinder heads.

In order to take account of the very limited space available in the cylinder head, various solution concepts have already been presented.

According to a rather general approach, it is considered expedient to perform various components to be integrated in the cylinder head as a structural unit. The German Offenlegungsschrift DE 37 31 211 A1 describes, for example, a fuel injection valve, which is formed integrally with an ignition device, ie injection device and ignition device form a coherent compact component. As a result, the number of components that are to be arranged in the cylinder head, reduced and thus reduced the space occupied by these components space.

However, a combined ignition / injection device of this type on the one hand forms a very expensive component. On the other hand, such a close arrangement of ignition device and injection device is not sought or preferred in all applications. Optionally, the igniter and the injector are spaced from each other in the cylinder head.

The German Offenlegungsschrift DE 197 53 965 A1 describes an internal combustion engine in which the injection valve - to reduce the required installation space - extends substantially within the intake passage and is arranged adjacent to the inlet valve. This should also be advantageous because the injection valve is cooled due to the arrangement in the channel by the intake fresh air.

This advantage is eliminated, at least for a return of hot exhaust gases in the inlet region of the internal combustion engine with activated exhaust gas recirculation. Should it become necessary to arrange the injector near the outlet, the DE 197 53 965 A1 no solution, since the proposed integration of the injection valve - rightly - is limited to the inlet channel and the analog arrangement of the injection valve in the outlet channel due to the thermal load is not possible.

Due to the direct arrangement of the injection valve in the inlet channel of the charge change is also influenced uncontrollably. The introduction of the valve in the channel also requires a seal of the valve against the channel to prevent leakage of fresh air or fresh mixture from the inlet channel into the environment. An exchange of the injection valve or an expansion of the injection valve requires the complete disassembly of the inlet portion of the internal combustion engine.

Against the background of the above, it is the object of the present invention, a cylinder head according to the preamble of claim 1 d. H. provide the generic type, which takes into account the very limited space in the cylinder head.

Another object of the present invention is to provide a method for forming such a cylinder head.

The first sub-task is solved by a cylinder head for an at least one cylinder having internal combustion engine with at least two charge exchange channels, namely at least one inlet channel for supplying the fresh air or the fresh mixture through at least one inlet opening in the at least one cylinder and at least one outlet channel for discharging the combustion gases at least one outlet opening of the at least one cylinder, which is characterized in that at least one shaft passes through at least one charge exchange channel, in the one Ignition device, an injection device or a cylinder head fixing means for mounting purposes is insertable.

According to the invention, a shaft is provided in at least one charge exchange channel. Although the flow cross section of this channel is reduced by the arrangement of the at least one shaft in the inlet and / or outlet and the flow in the channel changed. The charge change is not necessarily influenced uncontrollably, such as by - in the DE 197 53 965 A1 described - direct arrangement of an injection valve in the inlet channel. Rather, the shaft can be specifically designed in such a way that deliberately creates a twist, a tumble or another predetermined or suitable flow, that is generated.

The shaft serves to receive an ignition device, an injection device or a cylinder head fixing means and simultaneously isolates the respective component from the flow in the charge exchange channel d. H. with respect to the exhaust gas flow in the outlet channel or with respect to the fresh air or fresh mixture flow in the inlet channel. As a result of the use of a shaft, therefore, the arrangement of components in the hot exhaust gas flow or in the outlet channel is made possible.

The provision of a shaft also simplifies the assembly and disassembly of the corresponding introduced into the shaft component. A sealing of the introduced into the charge exchange channel component is not required. Although also the at least one shaft must be sealed from the environment in the way that no leakage current escapes from the charge exchange channel. But this seal is much easier to implement, as if the component is introduced directly into the charge exchange channel.

The injection device introduced into the shaft can be an outwardly opening injection nozzle, for example an injection nozzle operating according to the piezoelectric principle, which opens its nozzle tip in the context of the injection directed outward into the combustion chamber. As an injection device but can also serve an inwardly opening multi-hole injection nozzle, which offers cost advantages over the aforementioned piezoelectrically controlled injection nozzle.

A spark plug may be used as an ignition device and a threaded bolt as a cylinder head fastener.

Embodiments of the cylinder head in which the at least one shaft is not completely enclosed by the associated charge exchange channel, but only partially extends into the charge exchange channel are to be regarded as cylinder heads according to the invention, as long as the shaft passes through the charge exchange channel.

However, embodiments are advantageous in which the shaft is completely integrated into the charge exchange channel, since this is the largest space savings achieved.

Thereby, the object underlying the invention is achieved, namely to provide a cylinder head, which takes into account the very limited space in the cylinder head.

In principle, in the case of a cylinder head according to the invention, a shaft arranged in a charge exchange channel can extend beyond the charge exchange channel in the cylinder head and if necessary also penetrate or cut through coolant channels and / or the like.

Further advantageous embodiments of the cylinder head are discussed in connection with the subclaims.

Embodiments of the cylinder head are advantageous in which, in the mounted state, the ignition device, injection device or cylinder head fastening means introduced into the at least one shaft is arranged at least partially outside the at least one charge exchange channel.

This embodiment takes into account the fact that the introduced into the shaft ignition device or injector must extend into the combustion chamber of the cylinder, so that the fuel injected by injection directly into the combustion chamber and ignited with the ignition device, the fuel-air mixture. On the other hand remains a residual wall thickness between cylinder or combustion chamber and channel to a Form charge exchange channel and give the cylinder head the necessary strength. Consequently, the component introduced into the shaft is preferably at least partially positioned outside the at least one charge exchange channel in the mounted state.

A cylinder head attachment means - for example, a threaded bolt - is inherently at least partially outside of the cylinder head and thus arranged outside of the charge exchange channel, since the bolt extends into the cylinder block to connect the cylinder head with the cylinder block.

Embodiments of the cylinder head in which the cylinder head is a casting are advantageous.

Embodiments of the cylinder head in which the at least one shaft is sealed in a gas-tight manner relative to the at least one charge exchange channel in order to avoid a leakage current emerging from the at least one charge exchange channel are advantageous.

Embodiments of the cylinder head in which the at least one shaft is formed in one piece with the at least one charge exchange channel are advantageous. In this case, the at least one charge exchange channel and the shaft passing through this channel form a structural unit d. H. a monolithic component, which can preferably be formed by the fact that the cylinder head is produced by casting and a shaft is already provided originally in the cylinder head blank.

The one-piece d. H. monolithic construction makes a seal dispensable, because in principle no joints between channel and shaft arise through the fresh mixture or exhaust gas could escape from the charge exchange channel. In particular, the latter is a significant advantage of the integral formation of channel and shaft.

But are also advantageous embodiments of the cylinder head, in which in the at least one charge exchange channel, a sleeve is arranged, which forms the at least one shaft. In contrast to the embodiment described above are in the in question cylinder head shaft and charge exchange channel separate components ie the system of charge exchange channel and shaft is modular.

The cylinder head comprises at least one charge exchange channel into which a sleeve is introduced in the context of assembly or production, wherein the sleeve can be connected to the channel cohesively, positively or non-positively, which is not only the attachment of the sleeve in the channel, but also the seal the channel opposite the shaft and the surrounding area.

Embodiments of the cylinder head in which the sleeve connects two opposing openings provided in the at least one charge exchange channel are advantageous. In this embodiment, the shaft is completely integrated in the charge exchange channel, resulting in a maximum space savings in the cylinder head.

• ■ mindestens zwei Ladungswechselkanäle im Zylinderkopf vorgesehen werden, und
• ■ in mindestens einem Ladungswechselkanal mindestens ein Schacht in der Art angeordnet wird, daß dieser mindestens eine Schacht durch diesen mindestens einen Ladungswechselkanal hindurchführt, wobei der mindestens eine Schacht zur Aufnahme einer Zündvorrichtung, einer Einspritzvorrichtung oder eines Zylinderkopfbefestigungsmittel verwendet wird.

The second object of the invention is achieved by a method for forming a cylinder head of the aforementioned type, in which

• ■ at least two charge exchange channels are provided in the cylinder head, and
• At least one shaft is arranged in at least one charge exchange channel in such a way that it passes at least one shaft through this at least one charge exchange channel, wherein the at least one shaft is used to receive an ignition device, an injection device or a cylinder head attachment means.

What has already been said above for the cylinder head according to the invention also applies to the method according to the invention.

Advantageous are process variants in which the at least one shaft is integrally formed with the at least one charge exchange channel, which can be done, for example, that the cylinder head, starting from a cast cylinder head blank into which a shaft has already been integrated, is manufactured by reworking.

Process variants are advantageous in which a sleeve is used to form the at least one shaft and in which at least one charge exchange channel is arranged. In this procedure, the shaft is formed by introducing a sleeve subsequently in the charge exchange channel.

In this case, process variants are advantageous in which two opposite breakthroughs are provided in the at least one charge exchange channel, which openings are connected to one another using the sleeve.

Process variants in which the at least one shaft is sealed off from the at least one charge exchange channel are advantageous. Optionally, a seal of the shaft with respect to other functional spaces, such as a coolant channel or an oil reservoir, take place. A seal can also be made by means of O-ring or the like.

Fig. 1

schematisch einen Teilquerschnitt einer Ausführungsform eines Zylinderkopfes entlang der Zylinderlängsachse.

In the following the invention is based on an embodiment according to FIG. 1 described in more detail. Hereby shows:

Fig. 1

schematically a partial cross section of an embodiment of a cylinder head along the cylinder longitudinal axis.

FIG. 1 schematically shows a part of a cylinder head 1 in cross section along the cylinder longitudinal axis. 7

The cylinder 6 is formed by the cylinder head 1 and the cylinder block 2, wherein the combustion chamber 11 of the cylinder 6 is limited by a provided in the cylinder block 2 cylinder bore 13 and arranged in the cylinder head 1 combustion chamber roof fourteenth

In the cylinder head 1, a spark plug 10 serving as an ignition device 9 is arranged in the center of the combustion chamber roof 14 on the combustion chamber side. For discharging the combustion gases from the cylinder 6 and the combustion chamber 11, two outlet openings 8 and two serving as outlet channels 4 charge exchange channels 3 are provided, wherein in FIG. 1 in each case only one outlet opening 8 and an outlet channel 4 is shown or visible.

The exhaust port 8 and the exhaust port 4 is closed to the combustion chamber 11 by means of a valve 12, wherein the valve 12 is a suspended lift valve 12 which is displaced or deflected for expelling the combustion gases into the combustion chamber 11.

For connecting the cylinder head 1 with the cylinder block 2 bores 15, 16 are provided, wherein the cylinder block 1 and the cylinder head 2 for mounting - as in FIG. 1 shown - are arranged in the manner that the holes 15, 16 are aligned.

In the bores 15, 16 of the cylinder head 1 and the cylinder block 2, a threaded bolt is inserted and screwed (not shown).

In order to reduce the space required in the cylinder head 1, a shaft 5 is provided which passes through the outlet channel 4 and is aligned with the bores 15, 16 of the cylinder head 1 and the cylinder block 2 and in which serving as a cylinder head fastener threaded bolt for mounting purposes can be inserted ,

reference numeral

1

cylinder head

2

cylinder block

3

Charge exchange channel

4

outlet channel

5

shaft

6

cylinder

7

Longitudinal axis of the cylinder

8th

outlet

9

detonator

10

spark plug

11

combustion chamber

12

Valve

13

bore

14

Combustion chamber roof

15

Bore of the cylinder head

16

Bore of the cylinder block

Claims (12)

1. Cylinder head (1) for an internal combustion engine which has at least one cylinder (6) and at least two gas exchange channels (3), namely at least one inlet channel for feeding the fresh air or the fresh mixture through at least one inlet opening into the at least one cylinder (6) and at least one outlet channel (4) for leading the combustion gases away through at least one outlet opening (8) from the at least one cylinder (6), characterized in that at least one shaft (5) leads through at least one gas exchange channel (3), into which shaft (5) and an ignition apparatus, an injection apparatus or a cylinder head fastening means for assembly purposes can be inserted.
2. Cylinder head (1) according to Claim 1, characterized in that, in the assembled state, the ignition apparatus, injection apparatus or the cylinder head fastening means which is introduced into the at least one shaft (5) is arranged at least partially outside the at least one gas exchange channel (3).
3. Cylinder head (1) according to Claim 1 or 2, characterized in that the cylinder head (1) is a cast part.
4. Cylinder head (1) according to one of Claims 1 to 3, characterized in that the at least one shaft (5) is sealed in a gastight manner with respect to the at least one gas exchange channel (3).
5. Cylinder head (1) according to one of Claims 1 to 4, characterized in that the at least one shaft (5) is configured in one piece with the at least one gas exchange channel (3).
6. Cylinder head (1) according to one of Claims 1 to 4, characterized in that a sleeve which forms the at least one shaft (5) is arranged in the at least one gas exchange channel (3).
7. Cylinder head (1) according to Claim 6, characterized in that the sleeve connects two apertures to one another which lie opposite one another and are provided in the at least one gas exchange channel (3).
8. Method for forming a cylinder head (1) according to one of the preceding claims, in which method

   ■ at least two gas exchange channels (3) are provided in the cylinder head (1), and

   ■ at least one shaft (5) is arranged in at least one gas exchange channel (3) in such a way that said at least one shaft (5) leads through the at least one gas exchange channel (3), the at least one shaft (5) being used to receive an ignition apparatus, an injection apparatus or a cylinder head fastening means.
9. Method according to Claim 8, characterized in that the at least one shaft (5) is configured in one piece with the at least one gas exchange channel (3).
10. Method according to Claim 8, characterized in that, in order to form the at least one shaft (5), a sleeve is used and is arranged in the at least one gas exchange channel (3).
11. Method according to Claim 10, characterized in that two apertures which lie opposite one another and are connected to one another with the use of the sleeve are provided in the at least one gas exchange channel (3).
12. Method according to one of Claims 8 to 11, characterized in that the at least one shaft (5) is sealed with respect to the at least one gas exchange channel (3).

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