EP2660452A1 - Liquid cooled multi cylinder internal combustion engine and method to operate such an engine - Google Patents

Abstract

The engine has an exhaust manifold (10a) including an outer separating wall fluidly dividing exhaust lines (6). A coolant jacket includes a lower coolant jacket (16a) arranged among exhaust lines and an exterior side-wall (8) of a cylinder head (1). An upper coolant jacket (16b) is arranged on a side of the exhaust lines opposite to the lower coolant jacket, where a connection portion (13) is provided between the lower and upper coolant jackets that serve for passing coolant, and the connection portion is arranged in close proximity to a merged exhaust pipe.

Description

• an einer Montage-Stirnseite mit einem Zylinderblock verbindbar ist,
• mindestens einen integrierten Kühlmittelmantel aufweist,
• vier entlang der Längsachse des Zylinderkopfes in Reihe angeordnete Zylinder aufweist, wobei jeder Zylinder mindestens eine Auslaßöffnung zum Abführen der Abgase aus dem Zylinder via Abgasabführsystem aufweist, wozu sich an jede Auslaßöffnung eine Abgasleitung anschließt, und bei dem
• die Abgasleitungen der Zylinder stufenweise zu einer Gesamtabgasleitung zusammenführen, wobei jeweils die mindestens eine Abgasleitung eines außenliegenden Zylinders und die mindestens eine Abgasleitung des benachbarten innenliegenden Zylinders innerhalb des Zylinderkopfes unter Ausbildung eines Teilabgaskrümmers zu einer Teilabgasleitung zusammenführen, bevor die beiden Teilabgasleitungen der vier Zylinder außerhalb des Zylinderkopfes zu einer Gesamtabgasleitung zusammenführen, so dass das Abgasabführsystem in Gestalt von zwei Abgasaustrittsöffnungen an einer Außenseite des Zylinderkopfes austritt, wobei die zwei Abgasaustrittsöffnungen entlang der Längsachse des Zylinderkopfes versetzt und beabstandet zueinander und mit gleichgroßem Abstand zur Montage-Stirnseite angeordnet sind.

The invention relates to a liquid-cooled internal combustion engine with at least one cylinder head, the

• can be connected to a cylinder block at a mounting end face,
• has at least one integrated coolant jacket,
• has four cylinders arranged in series along the longitudinal axis of the cylinder head, wherein each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder via Abgasabführsystem, to which each outlet opening is followed by an exhaust pipe, and in which
• the exhaust gas lines of the cylinder gradually merge to form an overall exhaust line, wherein the at least one exhaust pipe of an outer cylinder and the at least one exhaust pipe of the adjacent inner cylinder merge within the cylinder head to form a partial exhaust gas line to form a partial exhaust gas line before the two partial exhaust gas lines of the four cylinders outside the cylinder head merge into an overall exhaust line, so that the Abgasabführsystem exits in the form of two exhaust gas outlet openings on an outer side of the cylinder head, wherein the two exhaust gas outlet openings along the longitudinal axis of the cylinder head offset and spaced from each other and are arranged at the same distance from the mounting end face.

Furthermore, the invention relates to a method for operating an internal combustion engine of the aforementioned type.

Internal combustion engines have a cylinder block and at least one cylinder head, which are connected together to form the cylinder at their mounting end faces. The cylinder block has cylinder bores for receiving the pistons or the cylinder tubes. The pistons are guided axially movable in the cylinder tubes and form together with the cylinder tubes and the at least one cylinder head, the combustion chambers of the internal combustion engine.

As part of the charge change, the expulsion of the combustion gases via the outlet openings of the at least four cylinders and the filling of the combustion chambers with fresh mixture or charge air via the inlet openings takes place. In order to control the charge cycle, an internal combustion engine requires control means and actuators to operate these controls. For controlling the charge cycle, four-stroke engines use almost exclusively globe valves as control members, 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. The required for the movement of the valves valve actuating mechanism including the valves themselves is referred to as a valve train. The at least one cylinder head is generally used to accommodate this valve train.

The intake ports leading to the intake ports and the exhaust ports, d. H. the exhaust pipes, which adjoin the outlet openings are at least partially integrated in the cylinder head according to the prior art. The exhaust pipes of the cylinders are usually combined and also present to form an overall exhaust gas line. The combination of exhaust pipes is generally and in the context of the present invention referred to as exhaust manifold.

In the internal combustion engine according to the invention, the exhaust gas lines of the four cylinders are gradually brought together in such a way that each merge the at least one exhaust pipe of an outer cylinder and the at least one exhaust pipe of the adjacent inner cylinder to a partial exhaust gas line and the two partial exhaust gas lines formed in this way Combine cylinders to form an overall exhaust gas line. With this measure, the total travel distance of all exhaust pipes and thus the volume of Abgasabführsystems can be significantly reduced.

The merging of the exhaust pipes to partial exhaust gas lines with the formation of two partial exhaust manifolds takes place within the cylinder head, whereas the two partial exhaust gas lines only outside the cylinder head to an overall exhaust gas line merge, so that the Abgasabführsystem exits in the form of two exhaust gas outlet openings on an outer side of the cylinder head.

In the internal combustion engine, the subject of the present invention, the two exhaust gas outlet openings along the longitudinal axis of the cylinder head are offset and spaced from each other, wherein the openings have an equal distance from the mounting end face of the cylinder head. This arrangement of the two outlet openings is particularly advantageous with regard to the realization of a low cylinder head height or as dense a packaging as possible, but assumes that two adjacent cylinders each form a group whose exhaust gas lines merge to partial exhaust gas lines.

If, on the other hand, the exhaust gas lines of the two outer cylinders and the exhaust gas lines of the two inner cylinders were each brought together to form a partial exhaust gas line to form a partial exhaust manifold, the outlet openings would lie at least in the vertical direction, ie. H. in the direction of the cylinder longitudinal axis, one above the other, d. H. offset from each other with different distances from the mounting end face.

To integrate the exhaust manifold largely into the at least one cylinder head, d. H. the merger of the exhaust pipes at least partially make already in the cylinder head, is advantageous for several reasons.

On the one hand, the integration of the partial exhaust gas lines into the cylinder head leads to a more compact design of the internal combustion engine and a denser packaging in the engine compartment. For others, there are cost advantages in the manufacture and assembly and a weight reduction of the internal combustion engine.

Furthermore, the integration may advantageously affect the location and operation of an exhaust aftertreatment system provided downstream in the exhaust evacuation system. The path of the hot exhaust gases to the various exhaust aftertreatment systems should be as short as possible so that the exhaust gases are given little time to cool down and the exhaust aftertreatment systems reach their operating temperature or light-off temperature as quickly as possible, in particular after a cold start of the internal combustion engine.

In this connection, efforts are made to minimize the thermal inertia of the portion of the exhaust pipes between the exhaust port on the cylinder and the exhaust aftertreatment system, which can be achieved by reducing the mass and the length of this section. The goal here is the extensive integration of the exhaust manifold in the cylinder head.

In supercharged by exhaust gas turbocharged internal combustion engines, it is desirable to keep the turbine as close as possible to the outlet, d. H. the exhaust ports of the cylinder, to order, in this way the exhaust enthalpy of the hot exhaust gases, which is largely determined by the exhaust gas pressure and the exhaust gas temperature to use optimally and to ensure a fast response of the turbocharger. Again, the thermal inertia and the volume of the conduit system between the outlet openings of the cylinder and the turbine should be minimized, which is why in turn the extensive integration of the exhaust manifold in the cylinder head is expedient.

Increasingly often, the exhaust manifold is largely integrated into the cylinder head in order to participate in a provided for in the cylinder head cooling and the manifold does not have to manufacture from thermally highly resilient materials that are expensive and more expensive.

This approach takes advantage of the fact that modern internal combustion engines are increasingly equipped or equipped with liquid cooling. In particular, supercharged internal combustion engines are subject to high thermal loads and therefore place increased demands on the cooling. The heat released during combustion by the exothermic, chemical conversion of the fuel is partially dissipated via the walls bounding the combustion chamber to the cylinder head and the cylinder block and partly via the exhaust gas flow to other components and the environment. In order to keep the thermal load of the cylinder head within limits, cooling by means of liquid cooling and forced convection targeted cooling inside the cylinder head is brought about. The heat is released inside the cylinder head to the coolant. 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.

Liquid cooling requires the equipment of the internal combustion engine or the cylinder head with at least one coolant jacket, d. H. the arrangement of the coolant through the cylinder head leading coolant channels, which causes a complex structure of the cylinder head construction. An integration of the partial exhaust gas lines in the cylinder head complicates the arrangement or formation of a sufficiently large cooling jacket volume in the mechanically and thermally highly loaded cylinder head in addition.

In light of the above, it is an object of the present invention to provide a liquid-cooled internal combustion engine according to the preamble of claim 1, which is optimized in terms of its liquid cooling.

Another object of the present invention is to provide a method for operating an internal combustion engine of the type mentioned.

• an einer Montage-Stirnseite mit einem Zylinderblock verbindbar ist,
• mindestens einen integrierten Kühlmittelmantel aufweist,
• vier entlang der Längsachse des Zylinderkopfes in Reihe angeordnete Zylinder aufweist, wobei jeder Zylinder mindestens eine Auslaßöffnung zum Abführen der Abgase aus dem Zylinder via Abgasabführsystem aufweist, wozu sich an jede Auslaßöffnung eine Abgasleitung anschließt, und bei dem
• die Abgasleitungen der Zylinder stufenweise zu einer Gesamtabgasleitung zusammenführen, wobei jeweils die mindestens eine Abgasleitung eines außenliegenden Zylinders und die mindestens eine Abgasleitung des benachbarten innenliegenden Zylinders innerhalb des Zylinderkopfes unter Ausbildung eines Teilabgaskrümmers zu einer Teilabgasleitung zusammenführen, bevor die beiden Teilabgasleitungen der vier Zylinder außerhalb des Zylinderkopfes zu einer Gesamtabgasleitung zusammenführen, so dass das Abgasabführsystem in Gestalt von zwei Abgasaustrittsöffnungen an einer Außenseite des Zylinderkopfes austritt, wobei die zwei Abgasaustrittsöffnungen entlang der Längsachse des Zylinderkopfes versetzt und beabstandet zueinander und mit gleichgroßem Abstand zur Montage-Stirnseite angeordnet sind,

die dadurch gekennzeichnet ist, dass

• in unterer Kühlmittelmantel, der zwischen den Abgasleitungen und der Montage-Stirnseite des Zylinderkopfes angeordnet ist, und ein oberer Kühlmittelmantel, der auf der dem unteren Kühlmittelmantel gegenüberliegenden Seite der Abgasleitungen angeordnet ist, vorgesehen sind, wobei mindestens eine Verbindung zwischen dem unteren Kühlmittelmantel und dem oberen Kühlmittelmantel vorgesehen ist, die dem Durchtritt von Kühlmittel dient, wobei die mindestens eine Verbindung benachbart zu einer Teilabgasleitung angeordnet ist, vorzugsweise im Bereich der Abgasaustrittsöffnung dieser Teilabgasleitung.

The first sub-task is solved by a liquid-cooled internal combustion engine with at least one cylinder head, the

• can be connected to a cylinder block at a mounting end face,
• has at least one integrated coolant jacket,
• has four cylinders arranged in series along the longitudinal axis of the cylinder head, wherein each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder via Abgasabführsystem, to which each outlet opening is followed by an exhaust pipe, and in which
• the exhaust gas lines of the cylinder gradually merge to form an overall exhaust line, wherein the at least one exhaust pipe of an outer cylinder and the at least one exhaust pipe of the adjacent inner cylinder merge within the cylinder head to form a partial exhaust gas line to form a partial exhaust gas line before the two partial exhaust gas lines of the four cylinders outside the cylinder head merge into an overall exhaust line, so that the Abgasabführsystem exits in the form of two exhaust gas outlet openings on an outer side of the cylinder head, wherein the two exhaust gas outlet openings offset along the longitudinal axis of the cylinder head and spaced from each other and are equally spaced from the mounting end face,

which is characterized in that

• in a lower coolant jacket, which is arranged between the exhaust pipes and the mounting end face of the cylinder head, and an upper coolant jacket, which is arranged on the opposite side of the lower coolant jacket side of the exhaust pipes, are provided, wherein at least one connection between the lower coolant jacket and the upper Coolant jacket is provided, which serves for the passage of coolant, wherein the at least one connection is arranged adjacent to a partial exhaust gas line, preferably in the region of the exhaust gas outlet opening of this partial exhaust gas line.

The cylinder head of the internal combustion engine according to the invention has a lower coolant jacket and a - the lower coolant jacket opposite - upper coolant jacket, wherein at least one compound is provided in the cylinder head, can flow through the coolant from the lower coolant jacket in the upper coolant jacket and / or vice versa.

In the present case, the connection is a breakthrough or flow channel which connects the lower coolant jacket to the upper coolant jacket and enables and realizes an exchange of coolant between the two coolant shells.

On the one hand, this basically means that cooling also takes place in the area of the connection. On the other hand, the conventional longitudinal flow of the coolant, d. H. the coolant flow in the direction of the longitudinal axis of the cylinder head, supplemented by a coolant transverse flow, which runs transversely to the longitudinal flow and preferably approximately in the direction of the cylinder longitudinal axes. The coolant flow passed through the at least one connection contributes significantly to the heat dissipation.

The cooling of the cylinder head can additionally and advantageously be improved by generating a pressure gradient between the upper and lower coolant jacket which in turn increases the velocity in the at least one joint, resulting in increased heat transfer due to convection.

According to the invention, the at least one connection is arranged adjacent to a partial exhaust gas line, preferably in the region of the exhaust gas outlet opening of this partial exhaust gas line from the cylinder head.

Thus, the at least one connection is also in the area in which the exhaust pipes merge and the hot exhaust gas of the cylinder of the internal combustion engine is collected, d. H. in an area in which the cylinder head is subjected to particularly high thermal loads. This has several reasons.

Firstly, the exhaust gas from two cylinders passes through the partial exhaust gas line, whereas a single exhaust gas line, which adjoins the outlet opening of a cylinder, is only supplied with the exhaust gas or part of the exhaust gas of a cylinder. Ie. the absolute amount of exhaust gas that can give off heat to the cylinder head is greater.

On the other hand, a partial exhaust gas line is exposed to hot exhaust gas for a longer period of time, whereas the exhaust gas lines of a single cylinder are only flowed through by hot exhaust gas during the charge cycle of this one cylinder.

In addition, it should be noted that in the inflow region of the partial exhaust line, the exhaust gas flows of the individual exhaust pipes must be more or less deflected in order to merge the exhaust pipes can. The individual exhaust gas flows therefore have in this area - at least partially - a speed component which is perpendicular to the walls of the Abgasabführsystems, whereby the heat transfer by convection and consequently the thermal load of the cylinder head is additionally increased.

For the reasons mentioned, it is therefore advantageous to arrange the at least one connection adjacent to a partial exhaust gas line.

The cylinder head of the internal combustion engine according to the invention is particularly suitable for supercharged internal combustion engines, which require efficient and optimized cooling due to higher exhaust gas temperatures.

Embodiments of the internal combustion engine with two cylinder heads are also internal combustion engines according to the invention. An internal combustion engine according to the invention may have two cylinder heads, if, for example, the cylinders are distributed over two cylinder banks. The merging of the exhaust pipes in the then two cylinder heads according to the invention is carried out in each case in the manner indicated above.

Thus, the first object of the invention is achieved, namely to provide a liquid-cooled internal combustion engine according to the preamble of claim 1, which is optimized in terms of their liquid cooling.

Further advantageous embodiments of the liquid-cooled internal combustion engine are discussed in connection with the subclaims.

Embodiments of the liquid-cooled internal combustion engine in which the at least one connection is completely integrated in the cylinder head are advantageous. This embodiment is different from, for example, designs of the cylinder head in which an opening is provided in the outer wall or outer side of the cylinder head which serves to supply or discharge coolant into and out of the upper and / or lower coolant jacket. Such an opening is not a connection in the sense of the invention.

In the process, the at least one connection can in the meantime be open to the outside via an access opening in the course of the production of the head, for example for removing a sand core. However, according to the embodiment in question, the finished cylinder head then has at least one connection completely integrated in the outer wall, for which purpose any access provided for the connection is to be closed.

In principle, embodiments are also possible in which a coolant supply or coolant discharge takes place in the region of the at least one connection, for which purpose a channel branches off from the at least one connection which emerges from the outer wall.

Advantageous embodiments of the liquid-cooled internal combustion engine, in which the distance Δ between the at least one compound and the partial exhaust gas line is smaller than half the diameter D of a cylinder with Δ ≤ 0.5 D, preferably smaller than one quarter of the diameter D of a cylinder with Δ ≤ 0.25 D, wherein the distance results from the distance between the outer wall of the partial exhaust gas line and the outer wall of the compound. The smaller the distance is formed, the greater the cooling effect achieved by the at least one connection, ie, the greater the heat dissipation.

Embodiments of the liquid-cooled internal combustion engine in which at least one connection is arranged on the side of the integrated partial exhaust gas manifold facing away from the four cylinders are advantageous. This has advantages in terms of heat balance and constructive advantages. The at least one connection is effectively outside the integrated exhaust manifold and thus in an area in which the space is greater than, for example, within the manifold, d. H. on the side facing the cylinders.

Embodiments of the liquid-cooled internal combustion engine in which at least two connections are provided, which are arranged on opposite sides of the system of elbows, are advantageous. A symmetrical arrangement of the at least two connections in the region of the partial exhaust manifolds or partial exhaust gas lines takes into account the fact that the system of exhaust pipes integrated in the cylinder head is generally symmetrical. The mutually corresponding formation of Abgasabführsystem and cooling thus ensures a symmetrical temperature distribution in the cylinder head.

Embodiments of the liquid-cooled internal combustion engine in which at least one additional connection is provided in the inner wall section which separates the two partial exhaust manifolds and projects into the exhaust gas removal system are advantageous.

The exhaust gas lines of the four cylinders of the at least one cylinder head of the internal combustion engine according to the invention are gradually brought together, wherein each an outer cylinder and the adjacent inner cylinder form a pair of cylinders whose exhaust lines merge within the cylinder head to a partial exhaust gas line, said partial exhaust gas lines separated from each other from the cylinder head. This is realized according to the invention by a constructive, d. H. representational, feature of the internal combustion engine, namely the fact that the outer wall sections, each separated in sections, the exhaust pipes of a pair of cylinders from each other in the direction of the outside of the cylinder head perpendicular to the longitudinal axis of the cylinder head less than the inner wall portion extending the two partial exhaust gas lines of the two Cylinder pairs within the cylinder head separates from each other.

The inner wall portion, in particular the free end of this section, is thermally highly loaded, since this section projects into the Abgasabführsystem, both partial exhaust manifolds limited and thus is acted upon by both sides with hot exhaust gas located in the manifolds. In this respect, it is advantageous to provide at least one connection or at least one additional connection in the inner wall section for the purpose of cooling this section.

Embodiments of the liquid-cooled internal combustion engine in which at least one exhaust-gas turbocharger is provided are advantageous, wherein the turbine of the at least one exhaust-gas turbocharger is arranged in the overall exhaust gas line and has an inlet region for supplying the exhaust gases. In this case, the entire exhaust gas of the four cylinders is fed to a turbine, wherein the at least one turbine is preferably arranged close to the engine, in order to make optimum use of the exhaust gas enthalpy of the hot exhaust gases

The advantages of an exhaust gas turbocharger, for example compared to a mechanical supercharger, are that there is no mechanical connection to the power transmission between the supercharger and the internal combustion engine. While a mechanical supercharger obtains the energy required for its drive completely from the internal combustion engine, the exhaust gas turbocharger uses the exhaust gas energy of the hot exhaust gases. The output of the exhaust gas flow to the turbine energy is used to drive a compressor, which promotes the charge air supplied to it and compressed, creating a Charging the cylinder is achieved. Optionally, a charge air cooling is provided, with which the compressed combustion air is cooled before entering the cylinder.

The charge is used primarily to increase the performance of the internal combustion engine. Charging is also a suitable means to shift the load spectrum to higher loads at the same vehicle boundary conditions, where the specific fuel consumption is lower.

Often a torque drop is observed when falling below a certain engine speed. The torque characteristic of a supercharged internal combustion engine is attempted to be improved by various measures. For example, by a small design of the turbine cross-section and simultaneous Abgasabblasung. Such a turbine is also referred to as a waste gate turbine. If the exhaust gas mass flow exceeds a critical value, a part of the exhaust gas flow is guided past the turbine or the turbine runner by means of a bypass line by opening a shut-off element as part of the so-called exhaust gas blow-off.

The torque characteristic of a supercharged internal combustion engine may be further represented by a plurality of turbochargers arranged in parallel or in series, i. H. by a plurality of turbines arranged in parallel or in series.

Also advantageous are embodiments of the liquid-cooled internal combustion engine, in which at least two exhaust gas turbochargers are provided, wherein a turbine of an exhaust gas turbocharger is arranged in each of the two partial exhaust gas lines.

Also advantageous are embodiments of the liquid-cooled internal combustion engine in which at least one exhaust gas turbocharger is provided, wherein the turbine of the at least one exhaust gas turbocharger is a double-flow turbine having two inlet channels arranged in an inlet region, one inlet channel each being connected to a partial exhaust gas line for supplying the exhaust gases , The partial exhaust gas lines can be merged in the turbine or downstream of the turbine to form an overall exhaust gas line.

In principle, the turbine can be equipped with a variable turbine geometry, which permits a further adaptation to the respective operating point of the internal combustion engine by adjusting the turbine geometry or the effective turbine cross section. In this case, adjustable guide vanes for influencing the flow direction are arranged in the inlet region of the turbine. Unlike the vanes of the rotating impeller, the vanes do not rotate with the shaft of the turbine.

If the turbine has a fixed invariable geometry, the vanes are not only stationary, but also completely immovable in the entry area, i. H. rigidly fixed. With a variable geometry, however, the guide vanes are indeed arranged stationary, but not completely immobile, but rotatable about its axis, so that the flow of the blades can be influenced.

Embodiments of the liquid-cooled internal combustion engine in which the smallest diameter of the at least one connection is smaller than the diameter d of an outlet opening of a cylinder with ≦ d are advantageous .

The diameter of the at least one compound has an influence on the flow velocity in the at least one connection, wherein the flow rate can be increased by reducing the diameter, which increases the heat transfer by convection. Advantages of the reduction of the diameter also with regard to the mechanical strength of the cylinder head.

Therefore, embodiments of the liquid-cooled internal combustion engine can be advantageous for the reasons mentioned, in which the smallest diameter of the at least one compound is smaller than half the diameter d of an outlet opening of a cylinder with ≤ 0.5d.

Embodiments of the liquid-cooled internal combustion engine in which the smallest diameter of the at least one connection is smaller than one third of the diameter d of an outlet opening of a cylinder with ≦ 0.33 d are also advantageous.

The second sub-task on which the invention is based, namely to show a method for operating an internal combustion engine according to a previously described type, is disclosed solved by a method which is characterized in that the combustion of the cylinders is initiated in the order 1 - 2 - 4 - 3, wherein the cylinders, starting with an outer cylinder sequentially counted and numbered along the longitudinal axis of the at least one cylinder head become.

The comments made for the internal combustion engine according to the invention also apply to the inventive method.

The exhaust pipes of the four cylinders of the at least one cylinder head of the internal combustion engine are combined within the cylinder head to partial exhaust gas lines. Basically, there is a risk that the cylinders influence each other during the charge change, which is fed by the partial integration of the manifold in the cylinder head this effect. By a suitable measure, namely by choosing a deviating from the usual firing sequence firing order, but can be countered.

According to the method of the invention, the combustion of the cylinders is initiated in the order 1 - 2 - 4 - 3, instead of operating the cylinders according to the conventional ignition pattern 1 - 3 - 4 - 2. Starting from the first cylinder, the ignition times in ° KW are measured as follows: 0 - 180 - 360 - 540. The numbering of the cylinders of an internal combustion engine is regulated in DIN 73021. For in-line engines, the cylinders are counted in order, starting with an external cylinder.

Although - as in the conventional ignition pattern also - ignite an outboard cylinder and the adjacent inner cylinder immediately behind the other, so that these cylinders have a thermodynamic offset of 180 ° KW, the ignition sequence according to the invention proves to be the more advantageous firing order. The reasons will be described in more detail below using the example of the cylinder pair comprising the first and second cylinders.

After the conventional firing pattern, the second cylinder is ignited in front of the first cylinder, so that the at least one outlet opening of the second cylinder is at the end of the closing operation, when the first cylinder to initiate the charge cycle its opens at least one outlet opening, ie releases. As a result of the pressure wave, which emanates from the first cylinder, exhaust gas already discharged from the second cylinder can be reintroduced into the second cylinder. Optionally, exhaust gas originating from the first cylinder also enters the previously fired second cylinder before its exhaust valves close.

If, in accordance with the ignition pattern according to the invention, the combustion in the first cylinder is initiated before the second cylinder, the above problem can be eliminated, namely with otherwise unchanged boundary conditions, ie. H. same valve opening times, in particular opening times, and when using the same manifold inherently same exhaust paths in Abgasabführsystem.

The fact that only the change of the sequence of ignition of the two adjacent cylinders leads to this result, is due to the different length of the exhaust pipes from the outlet opening of the respective cylinder to the part collection point of this pair of cylinders at which converge the exhaust pipes of the cylinder pair to a partial exhaust gas line. The result of the different lengths of exhaust pipes is that fresh air introduced into the exhaust gas removal system during a flushing process forms a longer fresh air column in the exhaust pipe of the first cylinder than in the exhaust pipe of the second cylinder.

Igniting the second cylinder before the first cylinder, the pressure wave, which emanates from the first cylinder, only a relatively short fresh air column overcome or push back into the second cylinder before the same pressure wave already discharged from the second cylinder exhaust gas or from the first cylinder originating exhaust gas introduces into the second cylinder.

If, on the other hand, the first cylinder in front of the second cylinder ignites, the pressure wave originating from the second cylinder must overcome a longer fresh air column or push back into the first cylinder before the same pressure wave has already removed exhaust gas from the first cylinder or exhaust gas originating from the second cylinder into the first cylinder.

The method according to the invention is a method for operating a compact internal combustion engine with short exhaust pipes, with which the problem of the mutual influence of the cylinders during the charge cycle can be eliminated.

• jeder Zylinder zur Einleitung einer Fremdzündung mit einer Zündvorrichtung ausgestattet wird, und
• die Zylinder in der Reihenfolge 1 - 2 - 4 - 3 gezündet werden, wobei die Zylinder beginnend mit einem außenliegenden Zylinder der Reihe nach entlang der Längsachse des mindestens einen Zylinderkopfes durchgezählt und numeriert werden.

Advantageous embodiments of the method, in which

• each cylinder is equipped with an igniter to initiate spark ignition, and
• the cylinders are ignited in the order 1 - 2 - 4 - 3, wherein the cylinders, starting with an external cylinder in sequence along the longitudinal axis of the at least one cylinder head are counted and numbered.

The above method variant relates to the application of the method in a spark-ignited internal combustion engine, for example a direct-injection spark-ignition engine, the cylinders of which are each equipped with an ignition device for initiating spark ignition.

• die Zylinder mittels Selbstzündung betrieben werden, und
• die Selbstzündung der Zylinder in der Reihenfolge 1 - 2 - 4 - 3 eingeleitet wird, wobei die Zylinder beginnend mit einem außenliegenden Zylinder der Reihe nach entlang der Längsachse des mindestens einen Zylinderkopfes durchgezählt und numeriert werden.

But are also advantageous embodiments of the method in which

• the cylinders are operated by auto-ignition, and
• the self-ignition of the cylinders is initiated in the order 1 - 2 - 4 - 3, wherein the cylinders, starting with an external cylinder in sequence along the longitudinal axis of the at least one cylinder head are counted and numbered.

The above process variant relates to methods in which the combustion is initiated by means of auto-ignition, and thus also on working methods, such as are commonly used in diesel engines.

It is also possible to use a hybrid combustion process with auto-ignition for operating a gasoline engine, for example the so-called HCCI process (Homogeneous-Charge Compression-Ignition), which is also referred to as a space ignition process or CAI process (Controlled Auto-Ignition) , This method is based on a controlled auto-ignition of the fuel supplied to the cylinder. The fuel - as in a diesel engine - under excess air, that is, superstoichiometric, burned. The lean-burn gasoline engine has comparatively low nitrogen oxide emissions NO _x due to the low combustion temperatures and also no soot emissions due to the lean mixture. In addition, the HCCI process leads to a high thermal efficiency. The fuel can be introduced both directly into the cylinder and in the intake manifold, with a direct injection additionally allows the Entdrosselung the internal combustion engine by eliminating the throttle.

Fig. 1

schematisch eine erste Ausführungsform des Zylinderkopfes im Querschnitt, und

Fig. 2

die in Figur 1 dargestellte Ausführungsform des Zylinderkopfes in der Seitenansicht, teilweise geschnitten.

In the following the invention is based on an embodiment according to the FIGS. 1 to 2 described in more detail. Hereby shows:

Fig. 1

schematically a first embodiment of the cylinder head in cross section, and

Fig. 2

in the FIG. 1 illustrated embodiment of the cylinder head in side view, partially cut.

FIG. 1 shows schematically and in section the cylinder head 1 of a first embodiment of the internal combustion engine together with a portion of the inlet housing 11 of a turbine 12th

The cylinder head 1 has four cylinders 3, along the longitudinal axis 2 of the cylinder head 1, d. H. arranged in series. The cylinder head 1 thus has two outer cylinders 3a and two inner cylinders 3b.

Each cylinder 3 has two outlet openings 4, to which the exhaust pipes 5 of the Abgasabführsystems connect for discharging the exhaust gases. The exhaust pipes 5 of the cylinders 3 lead gradually to an overall exhaust gas line 7, with the two exhaust pipes 5 of an outer cylinder 3a and the two exhaust pipes 5 of the adjacent inner cylinder 3b merging to form a partial exhaust manifold 10a, 10b forming a partial exhaust gas line 6, before the two partial exhaust gas lines 6 of the four cylinders 3, 3a, 3b merge to form an overall exhaust gas line 7.

In each case, the two exhaust pipes 5 of an outer cylinder 3a and the two exhaust pipes 5 of the adjacent inner cylinder 3b in sections by an outer wall portion 9a, which projects into the Abgasabführsystem separated from each other and the two partial exhaust gas lines 6 and the exhaust pipes 5 of the two inner cylinder 3b sections by an inner wall portion 9b, which also projects into the Abgasabführsystem. The outer wall sections 9a extend less far in the direction of the outer side 8 of the cylinder head 1 than the inner wall section 9b.

At the in FIG. 1 1, the inner wall section 9b extends with the free end 9c to the outer side 8 of the cylinder head 1, so that the exhaust gas streams of the partial exhaust gas lines 6 are separated from one another by the inner wall section 9b until they leave the cylinder head 1 and the exhaust gas removal system takes the form of two exhaust gas outlet openings on the outer side 8 exits the cylinder head 1 (see FIG. 2 ). The exhaust pipes 5 of the cylinder 3 and the partial exhaust gas lines 6 of the cylinder pairs are brought together only outside of the cylinder head 1 to form an overall exhaust gas line 7. In this respect, the exhaust manifold 10 is only partially integrated in the cylinder head 1. The manifold section located inside the cylinder head 1 comprises two partial exhaust manifolds 10a, 10b.

In the entire exhaust line 7, the turbine 12 of an exhaust gas turbocharger is arranged, which is equipped for supplying the exhaust gases of the cylinder 3 with an inlet region 11. In this case, the entire exhaust line 7 and the exhaust manifold 10 is flowing into the inlet housing 11 of the turbine 12, which is due to the close-coupled arrangement of the turbine 12.

In the FIG. 1 shown internal combustion engine is equipped with a liquid cooling, which has compounds 13.

FIG. 2 shows the in FIG. 1 illustrated embodiment of the cylinder head 1 in side view, partially cut. It should only be supplementary to FIG. 1 For that reason, reference is made to FIG FIG. 1 , The same reference numerals have been used for the same components.

The liquid cooling comprises two integrated coolant jackets 16a, 16b, wherein a lower coolant jacket 16a, which is arranged between the exhaust pipes 5,6 and the mounting end face 14 of the cylinder head 1, and an upper coolant jacket 16b, which on the lower coolant jacket 16a opposite side of the exhaust pipes 5, 6 is arranged, are provided.

Between the lower coolant jacket 16 a and the upper coolant jacket 16 b three connections 13 are provided, which serve for the passage of coolant and which are arranged adjacent to the partial exhaust gas lines 6. The connections 13 extend to the mounting end face 14 and also serve to supply the head 1 with coolant via cylinder block.

Two connections 13 are arranged on the side of the integrated partial exhaust manifolds 10a, 10b facing away from the four cylinders 3, namely on opposite sides of the two partial exhaust manifolds 10a, 10b. An additional connection 13 is provided in the inner wall section 9b, which separates the two partial exhaust manifolds 10a, 10b from each other and projects into the Abgasabführsystem.

It can be seen that the two partial exhaust manifolds 10a, 10b emerge from the cylinder head 1 in the form of two exhaust gas outlet openings 15a, 15b on the outside 8. The two exhaust gas outlet openings 15a, 15b are offset along the longitudinal axis 2 of the cylinder head 1 and spaced from each other, wherein the openings 15a, 15b have an equal distance from the mounting end face 14 of the cylinder head 1.

reference numeral

1

cylinder head

2

Longitudinal axis of the cylinder head

3

cylinder

3a

outboard cylinder

3b

internal cylinder

4

outlet

5

exhaust pipe

6

Part exhaust pipe

7

Total exhaust pipe

8th

outlet side outside of the cylinder head

9a

outside wall section

9b

inside wall section

9c

free end of the inner wall section

10

exhaust manifold

10a

first partial exhaust manifold

10b

second partial exhaust manifold

11

Inlet housing or inlet area of the turbine

12

turbine

13

connection

14

Mounting-end side

15a

Exhaust gas outlet opening

15b

Exhaust gas outlet opening

16a

lower coolant jacket

16b

Upper coolant jacket

° CA

Degree crank angle

Δ

Distance between a connection and a partial exhaust gas line

D

Diameter of a cylinder smallest diameter of a compound

d

Diameter of an outlet opening of a cylinder

Claims (17)

Liquid-cooled internal combustion engine with at least one cylinder head (1), the - Is connectable to a cylinder block at a mounting end face (14), having at least one integrated coolant jacket (16a, 16b), - has four along the longitudinal axis (2) of the cylinder head (1) arranged in series cylinder (3), each cylinder (3) at least one outlet opening (4) for discharging the exhaust gases from the cylinder (3) via Abgasabführsystem, including connected to each outlet opening (4) an exhaust pipe (5), and in which - The exhaust pipes (5) of the cylinder (3) gradually merge into an overall exhaust line (7), wherein in each case the at least one exhaust pipe (5) of an outer cylinder (3a) and the at least one exhaust pipe (5) of the adjacent inner cylinder (3b) within the cylinder head (1) to form a partial exhaust gas line (6) while forming a partial exhaust manifold (10a, 10b), before the two partial exhaust gas lines (6) of the four cylinders (3, 3a, 3b) outside the cylinder head (1) become an overall exhaust gas line (FIG. 7), so that the Abgasabführsystem exits in the form of two exhaust gas outlet openings (15 a, 15 b) on an outer side (8) of the cylinder head (1), wherein the two exhaust gas outlet openings (15 a, 15 b) along the longitudinal axis (2) of the cylinder head (1 ) offset and spaced from each other and with the same distance to the mounting end face (14), characterized in that a lower coolant jacket (16a) which is arranged between the exhaust pipes (5, 6) and the mounting end face (14) of the cylinder head (1), and an upper coolant jacket (16b) which is located on the lower coolant jacket (16a) at least one connection (13) between the lower coolant jacket (16a) and the upper coolant jacket (16b) is provided, which serves for the passage of coolant, wherein the at least one Connection (13) adjacent to a partial exhaust gas line (6) is arranged. Liquid-cooled internal combustion engine according to claim 1, characterized in that the at least one connection (13) is completely integrated in the cylinder head (1). Liquid-cooled internal combustion engine according to claim 1 or 2, characterized in that the distance Δ between the at least one connection (13) and the partial exhaust gas line (6) is smaller than half the diameter D of a cylinder (3) with Δ ≤ 0.5 D. Liquid-cooled internal combustion engine according to one of claims 1 to 3, characterized in that the distance Δ between the at least one connection (13) and the partial exhaust gas line (6) is smaller than a quarter of the diameter D of a cylinder (3) with Δ ≤ 0.25 D. Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that at least one compound (13) on the four cylinders (3) facing away from the integrated Teilabgaskrümmer (10a, 10b) is arranged. Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that at least two connections (13) are provided which are arranged on opposite sides of the two partial exhaust manifolds (10a, 10b). Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that at least one additional connection (13) in the inner wall portion (9b), which separates the two partial exhaust manifold (10a, 10b) from each other and projects into the Abgasabführsystem is provided. Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that each cylinder (3) has at least two outlet openings (4) for discharging the exhaust gases from the cylinder (3). Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that at least one exhaust gas turbocharger is provided, wherein the turbine (12) of the at least one exhaust gas turbocharger in the total exhaust gas line (7) is arranged and has an inlet region (11) for supplying the exhaust gases. Liquid-cooled internal combustion engine according to one of claims 1 to 8, characterized in that at least two exhaust gas turbochargers are provided, wherein in each of the two partial exhaust gas lines (6) a turbine (12) of an exhaust gas turbocharger is arranged. Liquid-cooled internal combustion engine according to one of claims 1 to 8, characterized in that at least one exhaust gas turbocharger is provided, wherein the turbine (12) of the at least one exhaust gas turbocharger is a double-flow turbine having two in an inlet region (11) arranged inlet channels, wherein each one Inlet duct is connected to a partial exhaust gas line (6) for supplying the exhaust gases. Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that the smallest diameter of the at least one connection (13) is smaller than the diameter d of an outlet opening (4) of a cylinder (3) with ≤ d . Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that the smallest diameter of the at least one Connection (13) is smaller than half the diameter d of an outlet opening (4) of a cylinder (3) with ≤ 0.5d. Liquid-cooled internal combustion engine according to one of the preceding claims, characterized in that the smallest diameter of the at least one connection (13) is smaller than one third of the diameter d of an outlet opening (4) of a cylinder (3) with ≤ 0.33d. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that in the cylinders (3) combustion is initiated in the order 1 - 2 - 4 - 3, the cylinders (3) starting with an external cylinder (3a) sequentially numbered and numbered along the longitudinal axis (2) of the at least one cylinder head (1). A method according to claim 15, characterized in that - Each cylinder (3) is equipped to initiate a spark ignition with an igniter, and - The cylinders (3) are ignited in the order 1 - 2 - 4 - 3, wherein the cylinder (3) starting with an outer cylinder (3a) sequentially along the longitudinal axis (2) of the at least one cylinder head (1) counted and numbered. A method according to claim 15, characterized in that - The cylinders (3) are operated by auto-ignition, and - the self-ignition of the cylinder (3) in the order 1 - 2 - 4 - 3 is initiated, the cylinder (3) starting with an outer cylinder (3a) in sequence along the longitudinal axis (2) of the at least one cylinder head (1 ) and numbered.

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