EP2077388B1 - Combination with cylinder head and cylinder block and usage of such a combination - Google Patents

Description

The invention relates to a combination with cylinder head and cylinder block and an at least partially integrated in the cylinder head coolant jacket for an internal combustion engine having at least two cylinders according to the preamble of claim 1.

Furthermore, the invention relates to the use of such a combination.

Internal combustion engines have a cylinder block and a cylinder head, which is used to form the individual cylinder d. H. Combustion chambers are connected to one another at a mounting end face.

The cylinder block has a corresponding number of cylinder bores for receiving the pistons or the cylinder tubes. The pistons are guided axially movably in the cylinder tubes and, together with the cylinder tubes and the cylinder head, form the combustion chambers of the internal combustion engine.

The cylinder head is often used to hold the valve train. In order to control the charge cycle, an internal combustion engine requires control means and actuators to operate these controls. As part of the charge change, the expulsion of the combustion gases via the outlet openings of the cylinder and the filling of the combustion chamber takes place ie the intake of the fresh mixture or the fresh air through the inlet openings. To control the charge cycle four-stroke engines almost exclusively lift valves are used as control members that perform an oscillating lifting movement during operation of the internal combustion engine and thus release the inlet and outlet ports and close. The required for the movement of the valves valve actuating mechanism including the valves themselves is referred to as a valve train.

It is the task of the valve train to open the intake and exhaust ports of the combustion chamber in time or close, with a quick release of the largest possible flow cross sections is sought to keep the throttle losses in the incoming and outflowing gas flows low and the best possible filling of the Combustion chamber with fresh mixture or an effective ie To ensure complete removal of the exhaust gases. Therefore, according to the prior art, increasingly two or more inlet and outlet ports are provided.

The inlet ducts leading to the inlet openings and the outlet ducts or exhaust ducts adjoining the outlet openings are at least partially integrated in the cylinder head according to the prior art. If the cylinders have more than one exhaust port, the exhaust pipes of a single cylinder are often combined - within the cylinder head - into a partial exhaust line associated with the cylinder, these partial exhaust pipes then being merged outside the cylinder into a single overall exhaust line. The merging of the exhaust pipes up to the total exhaust gas line is generally and in the context of the present invention referred to as exhaust manifold or manifold.

Downstream of the manifold, the exhaust gases are then optionally supplied to the turbine of an exhaust gas turbocharger and / or one or more exhaust aftertreatment systems.

It is on the one hand endeavored to arrange the turbine as close to the outlet of the internal combustion engine, in order to make optimum use of the exhaust enthalpy of the hot exhaust gases and to ensure a rapid response of the turbocharger. On the other hand, the way the hot exhaust gases to the various exhaust aftertreatment systems should be as short as possible, so that the exhaust gases little time Cooling is granted and the exhaust aftertreatment systems reach their operating temperature or light-off as quickly as possible, especially after a cold start of the engine.

In this context, therefore, it is basically endeavored to minimize the thermal inertia of the portion of the exhaust pipe between exhaust port on the cylinder and exhaust aftertreatment system or between exhaust port on the cylinder and exhaust gas turbocharger, which can be achieved by reducing the mass and the length of this section.

In order to achieve the aforementioned objects, the exhaust manifold of the prior art is at least partially integrated in the cylinder head. A cylinder head, in which connects to each outlet opening an exhaust pipe and merge the exhaust gas lines of the cylinder within the cylinder head to an overall exhaust line, has a fully integrated into the cylinder head manifold, see, eg EP 1 006 272 A2 ,

The heat released during combustion by the exothermic, chemical conversion of the fuel is partly dissipated via the walls delimiting the combustion chamber to the cylinder head and the cylinder block and partly via the exhaust gas flow to the adjacent components and the environment. In order to keep the thermal load of the cylinder head within limits, a portion of the introduced into the cylinder head heat flow must be withdrawn from the cylinder head again.

In principle, it is possible to carry out the cooling in the form of air cooling or liquid cooling. Due to the significantly higher heat capacity of liquids compared to air can be dissipated with the liquid cooling much larger amounts of heat than is possible with an air cooling.

The liquid cooling requires the equipment of the internal combustion engine or the cylinder head and the cylinder block with a coolant jacket ie the arrangement of the coolant through the cylinder head leading coolant channels, which causes a complex structure of the cylinder head construction. 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 does not have as in the air cooling until the Cylinder head surface are routed to be dissipated. The heat is already in the interior of the cylinder head or block to the coolant, usually mixed with additives added water. The coolant is conveyed by means of a pump arranged in the cooling circuit, so that it circulates in the coolant jacket. The heat given off to the coolant is removed in this way from the interior of the cylinder head and removed from the coolant in a heat exchanger again.

A cylinder head with at least partially integrated exhaust manifold is thermally highly loaded, in particular, when the internal combustion engine is a supercharged internal combustion engine, which is why in the prior art usually a liquid cooling is selected and a coolant jacket is integrated in the cylinder head.

In addition, modern internal combustion engines are increasingly being equipped with exhaust gas recirculation (EGR). The exhaust gas recirculation i. the recirculation of combustion gases from the exhaust gas side to the intake side of the internal combustion engine has been identified as being expedient in order to comply with future limit values for pollutant emissions, in particular the limit values for nitrogen oxide emissions. Since the formation of nitrogen oxides requires not only an excess of air, but also high temperatures, there is a concept for reducing nitrogen oxide emissions, combustion processes d. H. Process with lower combustion temperatures to develop, with the exhaust gas recirculation is a means of lowering the temperatures.

wobei m_AGR die Masse an zurückgeführtem Abgas und m_Frischluft die zugeführte und gegebenenfalls komprimierte Frischluft bzw. Ladeluft bezeichnet.With increasing exhaust gas recirculation rate, the nitrogen oxide emissions can be significantly reduced. The exhaust gas recirculation rate X _{EGR is} determined as follows: $${\mathrm{x}}_{\mathrm{AGR}}\mathrm{=}{\mathrm{m}}_{\mathrm{AGR}}\mathrm{/}\left({\mathrm{m}}_{\mathrm{AGR}}\mathrm{+}{\mathrm{m}}_{\mathrm{fresh\; air}}\right)$$

where m _AGR the mass of recirculated exhaust gas and m _fresh air refers to the supplied and optionally compressed fresh air or charge air.

In diesel engines exhaust gas recirculation is also suitable for reducing unburnt hydrocarbon emissions in the partial load range and in gasoline engines for reducing fuel consumption by reducing throttle losses.

In order to achieve a significant reduction in nitrogen oxide emissions, especially in the stratified charge combustion direct injection internal combustion engines, high exhaust gas recirculation rates are required, which may be in the order of X _AGR ≈ 50% to 70%.

To realize these high recycling rates is a cooling of the recirculating exhaust gas d. H. a compaction of the exhaust gas by cooling mandatory. The density of the recirculated exhaust gas increases due to the cooling.

An internal combustion engine, which is equipped in the inlet region with at least one suction line for supplying the cylinder with fresh air or fresh mixture and a Abgasabführsystem for discharging the exhaust gases, has for recirculation of the exhaust gas usually at least one line which branches off from the Abgasabführsystem in the Inlet region opens again and is also referred to as exhaust gas recirculation line.

In the exhaust gas recirculation line, an external cooling device is usually provided for the reasons mentioned above, with the temperature in the hot exhaust gas stream is lowered, whereby the density of the exhaust gases is increased. The temperature of the cylinder fresh charge, which occurs in the mixture of fresh air with the recirculated exhaust gases, is thereby also lowered, whereby the cooling device of the exhaust gas recirculation contributes to a better filling of the combustion chamber. As a rule, liquid cooling is used.

To realize a liquid cooling, the cooling device has an inlet and an outlet for the cooling liquid, wherein the cooling liquid, the exhaust gas recirculation line, which passes the exhaust gas through the cooling device, preferably a coolant jacket surrounds or flows around. The coolant or the cooling liquid extracts the heat from the exhaust gas flow in accordance with the principle of a heat exchanger, both by heat conduction and by convection. In the coolant circuit, a pump is arranged for delivery, so that the coolant circulates. The heat given off to the coolant is dissipated in this way.

The need to cool the recirculated exhaust gas to realize high recirculation rates leads to the prior art to the need to provide an external cooling device, which is associated with significant costs.

In addition, an external cooling device is contrary to the fundamental goal of realizing the densest possible packaging of the entire drive unit in the engine compartment. It should be considered in particular that two circuits, namely a coolant circuit and a circuit for the exhaust gas recirculation, are to be formed with the inclusion of the cooling device, to promote the coolant, a pump and a heat exchanger are provided for heat dissipation. The individual units must be connected with pipes, pipes or hoses.

Against the background of the above, it is the object of the present invention to provide a combination according to the preamble of claim 1, which serves to form an internal combustion engine with exhaust gas recirculation and with those of the prior art - in connection with the cooling of the recirculated exhaust gas - known disadvantages are overcome.

Another object of the present invention is to demonstrate uses of such a combination.

The first object is achieved by a combination with cylinder head and cylinder block and an at least partially integrated in the cylinder head coolant jacket for an internal combustion engine according to the features of claim 1.

The combination according to the invention has an integrated in the combination EGR cooler in the form of a monolithically formed at least partially with the combination housing, which compared to the prior art d. H. an external cooling device has several advantages. The housing may be at least partially or completely integrated in the cylinder head, in the cylinder block or in the combination of cylinder head and cylinder block.

On the one hand, the integration of the housing d. H. the cooling device in the combination a tight packaging of the entire drive unit.

On the other hand, the integration of the housing in a liquid-cooled internal combustion engine advantageously leads to further synergy effects. The coolant jacket integrated in the cylinder head or cylinder block in the present case not only cools the cylinder head or block which is subjected to high thermal loads, but also the housing formed monolithically with the combination and thus the exhaust gas recirculated through this housing as part of the EGR.

According to the invention, the cooling of the recirculated exhaust gas using the refrigerant circuit of the combination, which is why the EGR cooler or the housing does not have to be equipped with its own separate Kühlmittelzuführöffnung or -abführöffnung. The line for supplying or discharging the coolant into and out of the housing and the seals usually to be provided are also eliminated with the requirement to form an independent Kühlmittclkreislauf. The number of components, as well as the assembly costs decrease considerably.

However, the combination according to the invention also offers cost advantages, since the EGR cooler, ie the housing, can already be taken into account in the production of the cylinder head blank and / or the cylinder block blank, which are generally produced by casting, which may be achieved by suitable extension or removal Modification of existing molds is realized and optionally by the arrangement of suitable cores. In addition to the lower production costs, the reduction in the number of components leads to a reduction in both the provision costs and the Assembly costs, with the assembly steps, which are omitted according to the invention, even in connection with these assembly steps possible assembly errors are obsolete.

The proposed combination thus triggers - as stated above - the first sub-task underlying the invention, namely to provide a combination which serves for the formation of an internal combustion engine with exhaust gas recirculation and with which from the prior art - in connection with the cooling of the recirculated exhaust gas - known disadvantages are overcome.

The housing has an inlet to supply the recirculating exhaust gas to the housing, and has an outlet to discharge the cooled in the housing exhaust gas from the housing in the suction side.

Preferably, to set the return rate, a control element, such as a valve, a slide or a flap to provide. This control device can be arranged both upstream of the housing and downstream of the housing, wherein a downstream control member is thermally less heavily loaded, so that optionally can be dispensed with a separate cooling of the control member or less temperature-resistant and thus less expensive materials for the preparation of the control member can be used.

On the other hand, a control member arranged upstream of the housing enables not only the adjustment of the return rate but also the bypassing of the housing d. H. the EGR cooler in embodiments of the combination in which upstream of the housing a bypass line branches off from the return line, with which the hot exhaust gas to be recycled when bypassing the housing d. H. EGR cooler is passed into the inlet region or on the intake side of the internal combustion engine. An embodiment of the combination with bypass line is described in connection with the figures and explained in more detail.

The control member can be fully or partially integrated into the cylinder head or in the cylinder block, which basically allows use of the liquid cooling to cool the control member, or arranged or attached from the outside of the cylinder head or block.

In addition to the housing according to the invention serving as a cooling device, a second EGR cooler can be provided, which is then arranged externally either according to the prior art or, in turn, according to the invention as a housing is at least partially integrated into the combination. Two EGR coolers may be helpful if two return lines are provided, for example, a high pressure EGR and a low pressure EGR.

According to the invention, the housing is at least partially integral with the cylinder head, so that at least parts of the housing and the cylinder head form a monolithic component.

Since the cylinder head is usually thermally loaded higher than the cylinder block, this has a cooling correspondingly high cooling capacity, which is advantageous if - as in the invention - the liquid cooling of the internal combustion engine is used for cooling the recirculating exhaust gas.

According to the invention, the housing is arranged at a distance from the at least two cylinders on the side facing the exhaust manifold. The housing is present on the exhaust side of the cylinder head d. H. provided on the exhaust side of the internal combustion engine, which offers a variety of advantages, for example, with respect to an arrangement of the housing on the suction side d. H. in the inlet area of the cylinder head.

For a shortened for the recirculated exhaust gas, which is taken from the Abgasabführsystem, the way to the housing ie the cooling device, which simplifies the supply of exhaust gas to the housing, in particular the supply line, which branches off from the Abgasabführsystem and opens into the housing, significantly shortened. This proves to be particularly advantageous in conjunction with other technical features, for example, in embodiments of the cylinder head, in which the return line branches off from the exhaust manifold inside the cylinder head ie the tap is integrated in the cylinder head.

On the other hand, the liquid-cooled cylinder head is usually cooled more intensively on the exhaust side than on the inlet side, since the head is - due to the principle - thermally higher load on the exhaust side by the hot exhaust gases than on the inlet side. The coolant jacket is therefore formed on the exhaust side of the cylinder head usually large-scale or großvolumiger so that the cooling power required for the cooling of the exhaust side can be realized.

In this respect, it is advantageous to arrange the housing according to the embodiment in question on the side of the manifold in order to be able to extract the amount of heat required by the exhaust gas flowing through the housing by means of the cooling or cooling power available here.

Advantageous, but not according to the invention, in this context may be embodiments of the combination in which the housing is arranged on the side of the exhaust manifold, which faces away from the mounting end face. In this case, the housing is located above the exhaust manifold, which forms a balcony-like projection even with complete integration into the cylinder head. The housing can be arranged or formed in an advantageous manner above this balcony. Such an arrangement of the housing proves to be advantageous also with regard to the cooling, if formed above the manifold between the manifold and the housing, an upper coolant jacket d. H. is provided, with which both the exhaust gas in the manifold and the flowing through the housing exhaust heat can be withdrawn.

According to the invention the housing is arranged on the side of the exhaust manifold, which faces the mounting end face.

In a manner analogous to the previously described embodiment, the housing is located below the exhaust manifold or below a balcony-like protrusion, which may be formed by the manifold. Sufficient cooling can be realized, for example, by providing a lower coolant jacket below the manifold between the manifold and the housing, by means of which heat is extracted from the exhaust gas both in the manifold and in the housing.

In addition, the arrangement of the housing on the side facing the mounting end side of the exhaust manifold has the additional advantage that the housing can be extended into the area of the cylinder block or extend. This measure can prove to be expedient or helpful, in particular, if a sufficiently high cooling capacity is to be realized.

According to the invention, the coolant jacket also extends between the housing and the at least partially integrated exhaust manifold. As already stated above, such a design of the coolant jacket has the advantage of immediately adjacent and therefore very efficient cooling, in which the heat extracted from the exhaust gas is conducted over a comparatively short distance to the coolant jacket in order to be taken up and removed by the coolant. In addition, a thermal overloading of the housing located between the cylinder head and cylinder head walls is counteracted.

The cylinder head wall located between the housing and the coolant jacket or between the manifold and the coolant jacket forms an advantageously short thermal bridge.

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

Advantageous embodiments of the combination in which the housing comprises an integrally formed with the cylinder head housing segment having an opening which is covered by a lid for forming the housing. A disassembled state open d. H. provided with an opening housing facilitates the formation of the housing interior, in particular during the production by means of casting. The structure of the mold is considerably simplified. For example, cast cores can be easily removed, but also ribs, as they are to be provided according to a preferred embodiment, are introduced into the housing in a simple manner.

The housing segment equipped with an opening is then closed during the assembly to form the complete housing with a lid. A seal of the housing can - if necessary - be realized with a seal which is to be arranged between the housing segment and the lid.

The proposed embodiment with an open housing segment also allows only by a slight modification of the mold both inventive Form combinations with EGR cooler ie with housing as well as conventional combinations without housing, and thereby increase the diversity of a particular engine series ie engine family at the expense of low additional costs.

If the housing is arranged on the side of the exhaust manifold, which faces the mounting end, embodiments of the combination are advantageous in which the end face of the opening and the mounting end face lie in a plane. This embodiment of the combination or opening allows the processing or post-processing of the mounting end face of the head and the end face of the opening in one operation, which reduces the manufacturing cost. In addition, in this embodiment of the housing or the combination of the cylinder block serve as a lid.

A possible sealing of the housing takes place advantageously by means of an extended cylinder head gasket. The introduction of a seal is not mandatory, but only optional, as long as it can be ensured that the housing is gas-tight.

An extended cylinder head gasket is particularly advantageous in the sealing of the housing when the housing extends from the cylinder head into the cylinder block, as provided in the embodiment described below. In this case, the use of an extended cylinder head gasket ensures, in particular, that the end face of each housing half lies in one plane with the respectively associated mounting end face of the cylinder head or cylinder block, which represents a considerable simplification in terms of production.

In addition to the embodiments described above, in which the housing is at least partially integrated in the cylinder head, embodiments of the combination are advantageous in which the housing is fully integrated into the combination in such a way that the housing is partially integral with the cylinder head and partially integral with the cylinder block is formed.

This embodiment allows the formation of an EGR cooler high cooling capacity with a correspondingly large-sized housing. The larger cylinder block compared to the cylinder head offers the required mass or the required component volume.

Also in this embodiment of the combination, the housing is preferably to be arranged on the side of the cylinder, which faces the exhaust manifold. The reasons are the already mentioned above, in particular the cooling provided on this side and the comparatively short distance which the exhaust gas has to cover until it enters the housing.

Advantageous in this context are embodiments of the combination in which the housing comprises both a housing segment formed integrally with the cylinder head, which is open towards the mounting end side, and a housing segment formed integrally with the cylinder block, which is open towards the mounting end side , wherein the two housing segments correspond to each other and form the housing in the assembled state of the combination.

But are also advantageous embodiments of the combination in which the housing comprises an integrally formed with the cylinder block housing segment having an opening which is covered by a lid for forming the housing.

If the housing is arranged on the side of the exhaust manifold, which faces the mounting end, embodiments of the combination are advantageous in which the end face of the opening and the mounting end face lie in a plane.

With respect to the two last-described embodiments, reference is made to the explanations which have been made above in connection with combinations in which an at least partially integrated in the cylinder head housing comprises an open housing segment.

Advantageous embodiments of the combination, in which at least one rib is disposed within the housing, which protrudes from the walls bounding the housing. The provision of ribs increases the surface of the inner wall of the housing and thus the heat transfer both by heat conduction and by convection.

Embodiments of the combination in which the exhaust gas lines of at least two cylinders combine to form an exhaust gas manifold within the cylinder head to form an overall exhaust gas line are advantageous. This embodiment is characterized in that the combination has a fully integrated in the cylinder head exhaust manifold.

The complete integration of the manifold supports efforts to make the cylinder head and the drive unit as compact as possible. In addition, the thermal inertia of the portion of the exhaust pipes between exhaust port on the cylinder and the exhaust aftertreatment system or between exhaust port on the cylinder and the exhaust gas turbocharger is further reduced because the mass and the length of the relevant exhaust pipes are reduced. The response of a turbine and the performance of an exhaust aftertreatment system are improved.

In addition, a cylinder head with fully integrated exhaust manifold due to the high thermal load on a relatively bulky coolant jacket, which can also be used for cooling the exhaust gas passed through the housing.

Preferably, a coolant jacket is introduced into the cylinder head, which has a lower coolant jacket, which is arranged between the exhaust pipes of the manifold and the mounting end face of the cylinder head, and an upper coolant jacket, which on the opposite side of the lower coolant jacket exhaust pipes d. H. the Krümmers is arranged, wherein these two coolant jackets are preferably interconnected by means of passages.

Embodiments in which each cylinder has at least two outlet openings for discharging the exhaust gases from the cylinder are advantageous. As already mentioned, during the change of charge the largest possible flow cross-section should be released quickly in order to achieve an effective d. H. To ensure complete removal of the exhaust gases.

Embodiments in which initially the exhaust gas lines of the at least two outlet openings of each cylinder are associated with a cylinder associated with it are advantageous Combine the partial exhaust line before the partial exhaust gas lines of at least two cylinders merge to the total exhaust line. The gradual merging of the exhaust pipes shortens the total length of all existing exhaust pipes.

Embodiments are advantageous in which a return line leading the exhaust gas to the housing branches off from the exhaust manifold inside the cylinder head.

According to this variant, the tapping point for exhaust gas recirculation is integrated into the cylinder head. The integrated into the cylinder head tapping point allows the one-piece design of manifold and return line d. H. the avoidance of training and thus the sealing of a junction between the manifold and return line, as it is mandatory for an external tap. The recirculating exhaust gas can be fed to the at least partially integrated in the cylinder head housing without having to leave the cylinder head d. H. out of this, which completely eliminates the risk of leakage up to the housing. Furthermore, the integration of the tap leads to a reduction in the number of components and a more compact design.

In addition, the integration of the tap in the cylinder head usually leads to a shortening of the return line. With the reduction of the line length and the volume of the return line decreases, which is why the response of the exhaust gas recirculation improves. The internal combustion engine thus has an exhaust gas recirculation with improved response and thus a fundamentally improved transient operating behavior.

Embodiments in which the line for returning exhaust gas branches off from a partial exhaust gas line are advantageous. If the return line branched off from the exhaust pipe of a single outlet opening, a much more pronounced backflow of the exhaust gas components discharged from the other outlet openings would be required, which however can not be realized, so that high return rates could not be realized. In addition, a strong pulsation would be observed.

However, embodiments in which the line for returning exhaust gas branches off from the overall exhaust gas line are also advantageous.

Embodiments are advantageous in which the return line connects to the manifold with the formation of a funnel-shaped inlet region, which facilitates the inflow of the exhaust gas into the return line.

The return line can - depending on the individual case - partially or completely be introduced by means of machining production process in the cylinder head blank.

The return line can also be partially or completely formed already during the casting of the cylinder head blank, which can be done by introducing a simple, outwardly open and therefore easily removable core.

Are advantageous - also for the aforementioned considerations - embodiments of the combination in which the line for the return of exhaust gas is rectilinear. The rectilinear design of the return line simplifies the production of the line considerably. A rectilinear return line can be formed for example in a simple manner by drilling from the outside.

In addition, a straight course can serve to shorten the length of the return line and thus to reduce the volume of the line and the notch effect on the cylinder head.

Embodiments of the combination in which the line for recirculating exhaust gas adjoins the integrated exhaust manifold are advantageous.

This embodiment is advantageous because the cylinder head in this way only slightly by the introduction d. H. the integration of the return line is weakened or affected. In particular, the length of the return line shortens. Such a running return line also limits the interpretation of the cylinder head construction with respect to other requirements or functions as little as possible.

For the same reasons, embodiments are also advantageous in internal combustion engine with three or more cylinders, in which - when tapped off a partial exhaust gas line - the Dedicated line for the return of exhaust gas from the partial exhaust gas line of an outer cylinder.

However, embodiments are also advantageous in which the return line branches off from the exhaust manifold or the entire exhaust line outside the cylinder head, for example to form a low-pressure EGR, in which the return line branches off downstream of a turbine provided in the exhaust system. The return line must be connected to the Abgasabführsystem, for example by means of a flange. The joint is on the one hand a potential leakage point for the unwanted escape of exhaust gases, which implies high demands on the seal. On the other hand, this connection is thermally highly loaded by the hot exhaust gases, so that high demands are placed on the execution of the connection.

Also advantageous are embodiments in which upstream of the housing a bypass line branches off from the return line, with which the recirculated exhaust gas is passed in bypassing the housing in the inlet region of the internal combustion engine. This embodiment allows the recycling of hot d. H. not cooled exhaust gases, which may be advantageous under certain operating conditions of the internal combustion engine.

It is advantageous to use a combination according to one of the aforementioned types, in particular in a supercharged internal combustion engine, since the exhaust gas recirculation and charging are often used in combination.

In addition, a supercharged internal combustion engine is thermally more heavily loaded than a comparable naturally aspirated engine, which is why the cylinder head of a supercharged internal combustion engine is usually equipped with a liquid cooling or a coolant jacket high cooling capacity, which can then be used according to the invention in an advantageous manner for cooling the recirculating exhaust gas.

Furthermore, the exhaust gas temperatures are higher in supercharged internal combustion engines, so that a cooling of the recirculated exhaust gas, in particular in supercharged internal combustion engines is required to realize high return rates.

The use of the combination according to the invention is advantageous, in particular in internal combustion engines, which are charged by means of turbocharging.

In these internal combustion engines, the turbine of an exhaust gas turbocharger is disposed in the overall exhaust line, thereby increasing the exhaust pressure upstream of the turbine and thus also the exhaust pressure in the manifold, which in turn facilitates the introduction of the exhaust gas streams in the return line - provided the return line branches upstream of the turbine from the manifold or the entire exhaust line. In this way, high return rates can be realized.

Upon removal of the exhaust gas downstream of the turbine in the context of a low-pressure EGR the recirculating exhaust gas is introduced upstream of the associated compressor in the intake, whereby a good mixing of the intake fresh air with the recirculated exhaust gas takes place when flowing through the compressor, which is particularly advantageous at high recirculation rates for the formation of a homogeneous fresh cylinder charge.

Fig. 1

in einer perspektivischen Darstellung den Zylinderkopf einer ersten Ausführungsform der Kombination mit Blick auf die Montage-Stirnseite des Zylinderkopfes,

Fig. 2

in einer perspektivischen Darstellung einen Ausschnitt des in Figur 1 gezeigten Zylinderkopfes mit Blick auf die Montage-Stirnseite des Zylinderkopfes und das offen ausgebildete im Zylinderkopf integrierte Gehäusesegment,

Fig. 3

in einer perspektivischen Darstellung den in Figur 1 gezeigten Zylinderkopf teilweise geschnitten,

Fig. 4

in einer schematischen Darstellung eine zweite Ausführungsform der Kombination in einer Seitenansicht,

Fig. 5a

in einer perspektivischen Darstellung einen Ausschnitt des Zylinderkopfes einer dritten Ausführungsform der Kombination mit Blick auf das offen ausgebildete im Zylinderkopf integrierte Gehäusesegment und einem Steuerorgan in einer ersten Position,

Fig. 5b

in einer perspektivischen Darstellung den in Figur 5a gezeigten Zylinderkopf der Kombination mit dem Steuerorgan in einer zweiten Position, und

Fig. 5c

in einer perspektivischen Darstellung den in Figur 5a gezeigten Zylinderkopf der Kombination mit dem Steuerorgan in einer dritten Position.

In the following the invention is based on three embodiments according to the FIGS. 1 to 4 and 5a . 5b and 5c described in more detail. Hereby shows:

Fig. 1

3 is a perspective view of the cylinder head of a first embodiment of the combination with a view of the mounting end face of the cylinder head,

Fig. 2

in a perspective view a section of the in FIG. 1 shown cylinder head with a view of the mounting end face of the cylinder head and the open formed in the cylinder head integrated housing segment,

Fig. 3

in a perspective view the in FIG. 1 partly shown cylinder head,

Fig. 4

in a schematic representation of a second embodiment of the combination in a side view,

Fig. 5a

3 is a perspective view of a section of the cylinder head of a third embodiment of the combination with a view of the open-form housing segment integrated in the cylinder head and a control element in a first position;

Fig. 5b

in a perspective view the in FIG. 5a shown cylinder head of the combination with the control member in a second position, and

Fig. 5c

in a perspective view the in FIG. 5a shown cylinder head of the combination with the control member in a third position.

FIG. 1 shows a perspective view of the cylinder head 2 of a first embodiment of the combination with a view of the mounting end face 8 of the cylinder head. 2

Shown is the cylinder head 2 of a four-cylinder in-line engine. Each of the four cylinders 7 is provided with two inlet openings 22 and two outlet openings 21, with an exhaust pipe for discharging the exhaust gases adjoining each outlet opening 21. The exhaust pipes lead within the cylinder head 2 to form an exhaust manifold 16 together to form an exhaust manifold 16. The in FIG. 1 shown cylinder head 2 thus has a fully integrated exhaust manifold. 4

It is a housing 5 is provided, which serves for cooling rückzuführendem exhaust gas and integrally formed with the cylinder head 2 housing segment 9, 9a having an opening 10 which is closed during assembly by means of a lid to form the complete housing 5 ,

The housing 5 or housing segment 9, 9a is - spaced to the cylinders 7 - arranged on the side of the cylinder 7, which faces the exhaust manifold 4, ie on the exhaust side, and there below a formed by the manifold 4 balcony-like projection that is on the Side of the exhaust manifold 4, which faces the mounting end face 8.

The end face 11 of the housing opening 10 lies with the mounting end face 8 in a plane. This embodiment of the opening 10 allows the machining of the mounting end face 8 of the head 2 and the end face 11 of the opening 10 in one operation and an advantageous sealing of the housing 5 by means of an extended cylinder head gasket.

In FIG. 1 can also be seen the control member 17, with which the amount is set to recirculating exhaust gas. In the present case, the control member 17 is designed as a pivotable flap and arranged upstream of the housing 5, wherein the flap in the position shown closes the inlet for the exhaust gas into the housing 5. After flowing through the housing 5, the recirculated and cooled exhaust gas exits through an exit 20 from the housing 5 again.

FIG. 2 shows in a perspective view a section of the in FIG. 1 shown cylinder head 2 with a view of the mounting end face 8 of the cylinder head 2 and the open formed in the cylinder head 2 integrated housing segment 9, 9a.

It should only be supplementary to FIG. 1 For that reason, reference is otherwise made to the description of FIG FIG. 1 , The same reference numerals have been used for the same components.

How out FIG. 2 can be seen, an open trained housing segment 9, 9a allows the arrangement of cooling fins 6 in the interior of the housing 5, whereby the heat transfer and thus the cooling capacity of serving as an EGR cooler housing 5 are increased. The ribs 6 protrude from the housing 5 bounding walls and in the present case of the wall of the housing 5, the exhaust manifold 4 and thus the arranged between the manifold 4 and housing 5 lower coolant jacket (not shown - see FIG. 3 ) is facing. The main flow direction of the exhaust gas to be recirculated extends in the direction of the longitudinal axis of the cylinder head 2.

FIG. 3 shows in a perspective view the in FIG. 1 shown cylinder head 2 partially cut so that the structure of the exhaust manifold 4, the integrated EGR tap and the return line 18 can be seen.

It should only be complementary to the FIGS. 1 and 2 For that reason, reference is otherwise made to the description of FIG FIGS. 1 and 2 , The same reference numerals have been used for the same components.

How out FIG. 3 As can be seen, the exhaust pipes of each cylinder initially lead to a cylinder associated with the partial exhaust line 15 before the four partial exhaust gas lines 15 of the four cylinders merge to form a common total exhaust gas line.

For the return of exhaust gas in the cylinder head 2, a line 18 is integrated, which branches off from the integrated in the cylinder head 2 exhaust manifold 4. At the in FIG. 3 illustrated embodiment, the return line 18 branches off from a partial exhaust gas line 15 of the manifold 4 and that of the partial exhaust gas line 15 of an outer cylinder.

The return line 18 is rectilinear and connects to the partial exhaust gas line 15, forming a funnel-shaped inlet region. In this case, the diameter of the return line 18 at the junction in the direction of partial exhaust gas line 15 increases. The influx of exhaust gas is thereby simplified.

Starting from the partial exhaust gas line 15, the return line 18 leads into the housing 5 or the housing segment 9, 9a. The line 18 can be introduced as a result of the open housing segment 9, 9a by drilling from the outside.

Serving as the control member 17 flap is disposed at the transition of return line 18 and housing 5 and blocked in the position shown, the inlet 19 into the housing fifth

The cylinder head 2 is provided with a coolant jacket 12 having a lower coolant jacket 14 disposed between the exhaust pipes 15 of the manifold 4 and the mounting end 8 of the cylinder head 2, and an upper coolant jacket 13 facing the lower coolant jacket 14 Side of the exhaust pipes 15, ie, the manifold 4 is arranged, wherein these two coolant jackets 13, 14 are preferably interconnected by means of passages (not shown).

The lower coolant jacket 12, 14 is thus located between the exhaust manifold 4 and the housing 5, which is advantageous in terms of the simultaneous cooling of the exhaust gas both in the manifold 4 and in the housing 5.

FIG. 4 shows a schematic representation of a second embodiment of the combination 1 in a side view. In the illustrated embodiment, the housing 5 is partially integrated in the cylinder head 2 and partially in the cylinder block 3. This allows the formation of an EGR cooler high cooling capacity with a correspondingly large-sized housing. 5

The housing 5 is again arranged on the side of the cylinder, which faces the exhaust manifold 4. The housing 5 comprises a housing segment 9, 9a formed integrally with the cylinder head 2, which is open to the mounting end side, and a housing segment 9, 9b formed integrally with the cylinder block 3, which is open to the mounting end face, the two Housing segments 9a, 9b correspond to each other and form the housing 5 in the assembled state of the combination 1.

The FIGS. 5a . 5b . 5c show in a perspective view a detail of the cylinder head 2 of a third embodiment of the combination with a view of the open formed in the cylinder head 2 integrated housing segment 9, 9a and a control member 17 in different positions.

It should only the differences to the in FIG. 2 For the remainder, reference is made to the description of FIG FIGS. 1 and 2 , The same reference numerals have been used for the same components.

Unlike the in FIG. 2 illustrated embodiment, a slider 23 is used as a control member 17 which comprises a piston 25 which is arranged at the end of a translationally displaceable rod. The slider 23 not only serves to adjust the recirculation rate, but can also release a bypass line 24, which branches off from the return line 18 upstream of the housing 5. In this case, the slide 23 occupy four working positions, which are briefly described and explained below.

FIG. 5a shows the slider 23 in a first position in which the return line 18 is released and the bypass line 24 is closed. The entire recirculated exhaust gas flows through the housing 5 in this position of the slide 23 and is cooled.

FIG. 5b shows the slider 23 in a second position in which the return line 18 is closed. In this position of the slide 23, no exhaust gas is returned.

FIG. 5c shows the slide 23 in a third position, in which both the return line 18 and the bypass line 24 are released. In this position of the slide 23, the entire recirculated exhaust gas is recycled uncooled, bypassing the housing 5 in the inlet region of the internal combustion engine.

In a fourth - not shown - position of the slide, both the return line and the bypass line are released and the exhaust gas to be recirculated simultaneously opens the inlet 19 into the housing. For this purpose, only the guide for the slide on the side of the bypass line would be extended, so that the piston of the slide would come to lie in the fourth working position to the right of the open bypass line.

reference numeral

1

combination

2

cylinder head

3

cylinder block

4

exhaust manifold

5

casing

6

cooling fin

7

cylinder

8th

Mounting-end side

9

housing segment

9a

housing segment formed integrally with the cylinder head

9b

housing segment formed integrally with the cylinder block

10

housing opening

11

Front side of the housing opening

12

Coolant jacket

13

Upper coolant jacket

14

lower coolant jacket

15

Part exhaust pipe

16

Total exhaust pipe

17

control element

18

Line for recirculation of exhaust gas, return line

19

Entry into the housing

20

Exit from the housing

21

outlet

22

inlet port

23

pusher

24

bypass line

25

piston

Claims (8)

1. Combination (1) with cylinder head (2) and cylinder block (3) and a coolant jacket (12), which is at least partially integrated in the cylinder head (2), for an internal combustion engine having at least two cylinders (7), in which

   - the cylinder head (2) can be connected at an assembly end side (8) to the cylinder block (3),

   - each cylinder (7) has at least one outlet opening (21) for discharging the exhaust gases out of the cylinder (7),

   - an exhaust line is connected to each outlet opening (21),

   - the exhaust lines of at least two cylinders (7) merge, so as to form an exhaust manifold (4) which is at least partially integrated in the cylinder head (2), to form an overall exhaust line (16), and

   - a housing (5) through which exhaust gas flows is provided, spaced apart from the at least two cylinders (7), on the side facing towards the exhaust manifold (4), which housing (5) serves for cooling exhaust gas to be recirculated and is formed at least partially integrally with the cylinder head (2), such that at least parts of the housing (5) and of the cylinder head (2) form a monolithic component,
   characterized in that

   - the housing (5) is arranged on that side of the exhaust manifold (4) which faces towards the assembly end side (8), and

   - the coolant jacket (12) also extends between the housing (5) and the at least partially integrated exhaust manifold (4).
2. Combination (1) according to Claim 1, characterized in that the housing (5) comprises a housing segment (9, 9a) which is formed integrally with the cylinder head (2) and which has an opening (10) which is covered by means of a cover for forming the housing (5).
3. Combination (1) according to Claim 2, in which the housing (5) is arranged on that side of the exhaust manifold (4) which faces towards the assembly end side (8), characterized in that the end side (11) of the opening (10) lies in a plane with the assembly end side (8).
4. Combination (1) according to Claim 1, characterized in that the housing (5) is fully integrated into the combination (1) in such a way that the housing (5) is formed partially integrally with the cylinder head (2) and partially integrally with the cylinder block (3).
5. Combination (1) according to Claim 4, characterized in that the housing (5) comprises both a housing segment (9a) which is formed integrally with the cylinder head (2) and which is open towards the assembly end side (8), and a housing segment (9b) which is formed integrally with the cylinder block (3) and which is open towards the assembly end side (8), with the two housing segments (9a, 9b) corresponding to one another and forming the housing (5) when the combination (1) is in the assembled state.
6. Combination (1) according to one of the preceding claims, characterized in that the housing (5) has arranged within it at least one rib (6) which projects from the walls delimiting the housing (5).
7. Use of a combination (1) according to one of the preceding claims for a supercharged internal combustion engine.
8. Use according to Claim 7, characterized in that the internal combustion engine is supercharged by means of exhaust-gas turbocharging.

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