EP2385229B1 - Internal combustion engine with liquid cooling system - Google Patents

Description

• mindestens einen Zylinderkopf, und
• eine Flüssigkeitskühlung, die mindestens zwei im Zylinderkopf integrierte Kühlmittelmäntel aufweist, wobei jeder Zylinder auslaßseitig mindestens eine Auslaßöffnung zum Abführen der Abgase und einlaßseitig mindestens eine Einlaßöffnung zum Zuführen von Frischluft aufweist.

The invention relates to an internal combustion engine comprising at least one cylinder

• at least one cylinder head, and
• a liquid cooling system comprising at least two coolant jackets integrated in the cylinder head, each cylinder having on the outlet side at least one outlet opening for discharging the exhaust gases and on the inlet side at least one inlet opening for supplying fresh air.

An internal combustion engine of the type mentioned is used as a drive for motor vehicles. In the context of the present invention, the term internal combustion engine includes diesel engines and gasoline engines, but also hybrid internal combustion engines, d. H. Internal combustion engines operated by a hybrid combustion process.

Internal combustion engines have a cylinder head and a cylinder block which are used to form the individual cylinders, d. H. Combustion chambers are connected to each other at their mounting end faces.

The cylinder head is usually used to hold the valve train. It is the task of the valve drive to release the inlet and outlet openings of the combustion chamber in time or to close.

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

A valve actuator often includes a camshaft on which a plurality of cams are disposed. Basically, a distinction is made between an underlying camshaft and an overhead camshaft. In this case, reference is made to the parting plane, d. H. Mounting surface, between cylinder head and cylinder block. If the camshaft is above the mounting surface, it is an overhead camshaft, otherwise a camshaft below. Overhead camshafts are preferably stored in the cylinder head.

For receiving and supporting a camshaft in the cylinder head a so-called camshaft receiving is provided with at least two bearings, the bearings are usually made in two parts and each include a bearing saddle and connectable to the bearing saddle bearing cap. The camshaft is in the region of the shaft journals, which are arranged spaced apart along the camshaft axis to each other and are usually formed as thickened shaft shoulders stored. It can be formed as separate components or integrally with the camshaft receiving bearing cap and bearing saddles. Between the camshaft and the bearings bearing shells can be arranged as intermediate elements.

When assembled, each bearing saddle is connected to the corresponding bearing cap. Each one bearing saddle and a bearing cap form - possibly in cooperation with bearing shells as intermediate elements - a bore for receiving a pin. The holes are usually with engine oil, d. H. Lubricating oil supplied, so that ideally forms between the inner surface of each hole and the associated pin with rotating camshaft - similar to a plain bearing - a viable lubricating film. Alternatively, a bearing may also be formed in one piece, for example in a built camshaft.

To supply the bearings with oil, a pump is provided for the delivery of engine oil, wherein the pump via the supply line, the Nockenwellenaufiiahme, from the channels to the at least two camps, supplied with engine oil. In this case, the supply line leads to the state of the art of the pump through the cylinder block for camshaft receiving and thereby passes the so-called Hauptölgalerie.

To form the main oil gallery, a main supply channel is often provided in the cylinder block, which is aligned along the longitudinal axis of the crankshaft. The main supply channel can be arranged above or below the crankshaft in the crankcase or integrated into the crankshaft. From the main oil gallery channels lead to the bearings of the crankshaft.

The proposed pump itself is supplied according to the prior art via suction, which leads from an oil pan to the pump, coming from the oil pan engine oil and must have a sufficiently large flow, d. H. ensure a sufficiently high delivery volume, and for a sufficiently high oil pressure in the supply system, d. H. Oil circulation, especially in the main oil gallery, provide.

The camshaft and the crankshaft or the associated bearings, d. H. Images are referred to in the context of the present invention as a consumer, since they need to fulfill and maintain their function engine oil or consume, d. H. must be supplied with engine oil.

Further consumers may be, for example, the bearings of a connecting rod or an optional balancing shaft. Also consumer in the above sense is also a peak oil cooling, which the piston crown for the purpose of cooling by means of nozzles from below, d. H. crankcase side, wetted with engine oil and thus oil needs, d. H. must be supplied with oil.

A hydraulically operable camshaft phaser or other valve train components, for example, for hydraulic valve clearance, also have a need for engine oil and require an oil supply.

No consumer in the aforementioned sense is provided in the supply line oil filter or oil cooler. Although these components of the oil circuit are supplied with engine oil. Due to the principle, however, an oil cycle entails the use of these components, which have only tasks, ie functions, which relate to the oil as such, whereas a consumer first makes the oil circulation necessary.

The friction in the consumers to be supplied with oil, for example, the bearings of the crankshaft, depends significantly on the viscosity and thus of the temperature of the oil provided and contributes to the fuel consumption of the internal combustion engine.

Basically, efforts are made to minimize fuel consumption. In addition to an improved, i. more effective, combustion is also the reduction of friction in the foreground of the efforts. A reduced fuel consumption also contributes to a reduction in pollutant emissions.

With regard to a reduction of the friction power, rapid heating of the engine oil and rapid heating of the internal combustion engine, especially after a cold start, are expedient. The comparatively rapid heating of the engine oil during the warm-up phase of the internal combustion engine ensures a correspondingly rapid decrease in viscosity and thus a reduction in the friction or friction power, in particular in the oil-supplied bearings.

From the prior art, for example, concepts are known in which the oil is actively heated by means of external heating device. However, the heater is an additional consumer in terms of fuel use, which runs counter to the objective of reducing fuel consumption.

Other concepts envisage storing the engine oil heated during operation in an insulated container and using it as needed, for example a restart of the internal combustion engine. A disadvantage of this approach is that the heated oil during operation can not be kept indefinitely at high temperature, which is why heating of the oil is usually required during operation of the internal combustion engine.

Both an external heater and an insulated container lead to an additional space requirement in the engine compartment and are detrimental to a dense packaging of the drive unit.

Apart from the above-mentioned devices, which cause additional costs and have an additional space requirement, an advantageous design of the oil circuit, in particular a suitable guidance of the supply line through the cylinder block or

Cylinder head, to assist the warming of the engine oil after a cold start, d. H. accelerate.

In connection with the oil cycle and the desired rapid heating of the oil after a cold start must be considered in principle that the cylinder head and the cylinder block are thermally highly stressed components that require cooling, and the heat balance of the internal combustion engine is primarily dominated by this cooling, d. H. the design of the internal combustion engine is determined by the cooling and not by the fastest possible heating of the engine oil.

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. The amount of heat dissipated from the surface of the internal combustion engine to the environment by radiation and heat conduction is not sufficient for efficient cooling, which is why cooling of the cylinder head is usually brought about deliberately by means of forced convection.

In principle, it is possible to carry out the cooling in the form of air cooling or liquid cooling. In the air cooling, the internal combustion engine is provided with a fan, wherein the heat dissipation takes place by means of a guided over the surface of the cylinder head air flow.

On the other hand, the liquid cooling requires the equipment of the internal combustion engine or the cylinder head and / or 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 structure. In this case, the mechanically and thermally highly stressed cylinder head is weakened by the introduction of the coolant channels on the one hand in its strength. On the other hand, the heat must not be directed to the cylinder head surface as in the air cooling, to be dissipated. The heat is already in the interior of the cylinder head to the coolant, usually mixed with additives added water. The coolant is thereby by means of a pump arranged in the cooling circuit promoted 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.

Water has the advantage over other coolants that it is non-toxic, readily available and inexpensive and also has a very high heat capacity, which is why water is suitable for the removal and removal of very large amounts of heat, which is generally considered advantageous.

Due to the higher heat capacity of a liquid compared to air can be dissipated with a liquid cooling much larger amounts of heat than with air cooling.

Modern internal combustion engines are also often charged by means of exhaust gas turbocharger or compressor and increasingly have integrated exhaust manifolds in the cylinder head. These measures result in that the cylinder head and the cylinder block are thermally loaded higher than in a conventional internal combustion engine, which is why increased cooling requirements must be met.

For the reasons mentioned, in an internal combustion engine according to the prior art for the formation of a liquid cooling, at least one coolant jacket is frequently integrated in the cylinder head.

In the internal combustion engine according to the invention, the cylinder head has at least two coolant jackets. The cylinder head may, for example, on the outlet side, 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 exhaust pipes.

The cooling should protect the internal combustion engine, in particular the cylinder head, reliably against thermal overload and preferably be so efficient that it can be dispensed with enrichment (λ <1) at high exhaust gas temperatures. When enriched, more fuel is injected than can be burned at all with the amount of air provided, and the additional fuel is also heated and vaporized, so that the temperature of the combustion gases decreases. However, this procedure is considered to be disadvantageous from an energetic point of view, in particular with regard to the fuel consumption of the internal combustion engine, and with regard to the pollutant emissions. In particular, enrichment does not always allow the engine to be operated in the manner required, for example, for a proposed exhaust aftertreatment system.

On the other hand, the engine should be removed by cooling no more heat than absolutely necessary because the heat extraction or the amount of heat extracted has an influence on the efficiency of the internal combustion engine. In the prior art, more than a quarter of the energy used is added to the coolant, i. H. usually to the cooling water, the liquid cooling discharged and discharged unused to the environment.

Against the background of the above, it is the object of the present invention to provide an internal combustion engine according to the preamble of claim 1, which is optimized both in terms of cooling and in terms of friction.

Such an internal combustion engine is in JP58035221 shown.

This object is achieved by an internal combustion engine according to claim 1.

The cylinder head of the internal combustion engine according to the invention has two independent coolant circuits, each comprising at least one coolant jacket and in particular can be operated with different coolants and preferably operated.

This embodiment or design of the liquid cooling allows a demand-based cooling of the inlet side on the one hand and the outlet side on the other hand, and independently of each other and according to the respective requirement profile.

According to the invention, the at least one coolant jacket of the one circuit on the outlet side and the at least one coolant jacket of the other circuit are arranged on the inlet side, so that different cooling capacities can be realized for the inlet side and the outlet side and not only by using different coolants. Rather, the pump power of each circuit can be independently selected and adjusted and thus also the coolant flow rate, d. H. the delivery volume. In this way, influence can be taken on the flow rate, which decisively co-determines the heat transfer by convection.

In this way, less heat on the inlet side and more heat on the outlet side can be withdrawn from the cylinder head.

In particular, the internal combustion engine according to the invention allows the use of oil as the coolant for the inlet side and the use of water as a coolant for the thermally higher or thermally highly loaded exhaust side of the cylinder head.

Oil has a lower heat capacity compared to water, whereby the cooling performance on the inlet side can be significantly reduced compared to a use of water as a coolant. The inventive design of the liquid cooling system offers the possibility of extracting only as much heat from the cylinder head on the inlet side as is actually required to prevent overheating, whereas the inlet side according to the prior art is more strongly cooled due to the uniform use of water as the coolant as this is actually required, since the design of the cooling takes place in view of the thermally stressed outlet side. The internal combustion engine according to the invention is thus optimized in terms of cooling. The efficiency of the internal combustion engine is increased by the liquid cooling according to the invention.

In addition, the use of oil as a coolant for the at least one inlet-side coolant jacket has a further advantage. If the inlet-side coolant jacket forms the oil circuit of the internal combustion engine, which supplies oil to consumers via the supply line, then the engine oil heats up faster after a cold start.

The oil then flows through the inlet-side coolant jacket, when passing through the cylinder head, whose very own function is the presently desired heat transfer. The inlet-side coolant jacket is used for heating the oil during the warm-up phase and according to its original function for cooling the cylinder head with warmed-up internal combustion engine. In both cases, the inlet-side coolant jacket serves the heat input into the oil.

While the heat that is introduced on the inlet side into the coolant after a cold start, in the internal combustion engine according to the invention advantageously provides for a rapid heating of the oil and thus improves the performance of the internal combustion engine, the heat, which according to the prior art in the than Coolant serving cooling water is introduced, discharged unused. The latter heat transfer even precludes rapid heating of the oil. The heating of the oil during the warm-up phase is delayed, since a warm-up of the internal combustion engine is counteracted and thus also a heating of the oil when passing the cylinder head or cylinder block.

The inlet-side coolant jacket proves to be extremely suitable with regard to the heating of the oil during the warm-up phase in principle. On the one hand, the coolant jacket-in particular in comparison to a conduit-has a large surface area, which increases the heat transfer due to convection. On the other hand, the cylinder head, in which the coolant jacket is integrated, thermally particularly high load, which promotes the heat input into the engine oil during the warm-up phase due to the relatively large temperature difference or temperature gradient.

For the reasons mentioned above, in particular embodiments of the internal combustion engine are therefore advantageous in which the at least one outlet-side coolant jacket belongs to a cooling water circuit, whereas the at least one inlet-side coolant jacket belongs to an oil circuit.

The inventively designed engine proves to be particularly advantageous during the warm-up phase, in particular after a cold start. After a stoppage of the vehicle, d. H. at a restart of the engine, the oil flows through the oil circuit belonging to the inlet side coolant jacket of the cylinder head, which heats up comparatively quickly due to the expiring combustion processes, which can be entered immediately after the start of larger amounts of heat in the oil. The oil provided to the consumers is thus heated faster.

Higher temperature heated oil has lower viscosity, which lowers engine friction and improves efficiency. As a result, by heating the oil, the fuel consumption of the internal combustion engine is noticeably reduced, in particular after a cold start.

With the internal combustion engine according to the invention - as detailed - the object underlying the invention is achieved, namely to provide an internal combustion engine, which is optimized both in terms of cooling and in terms of friction.

The essential advantage of the procedure according to the invention over concepts in which the oil is actively heated by means of a heating device consists in the comparatively simple construction of the oil heating according to the invention. In principle, no additional components are required, in particular no external heating device. With the heater also eliminates the conditional by such a device fuel consumption. According to the invention, a coolant jacket to be provided for the formation of a liquid cooling system is assigned to an already existing oil circuit, in order to be able to heat the oil more quickly during warming up.

With regard to concepts in which warmed up engine oil heated in operation in an insulated container and used in a restart of the internal combustion engine to supply the consumer, it must be taken into account that the heated oil in operation can not be kept indefinitely at high temperature and also this concept, although no additional fuel, but then needed additional components.

Embodiments of the internal combustion engine in which the cooling water circuit does not comprise an inlet-side coolant jacket are advantageous. Ie. the inlet side of the cylinder head is exclusively oil-cooled, which is why the heat is not dissipated unused with the cooling water.

This embodiment or design of the liquid cooling ensures that the heat removed from the cylinder head inlet side heat is used exclusively and completely for heating the engine oil and is not dissipated unused on the cooling water to the environment. As a result, the heat balance of the internal combustion engine is further optimized.

In internal combustion engines in which the at least one inlet-side coolant jacket belongs to an oil circuit, embodiments are advantageous in which the at least one cylinder head is connected to a mounting end face with a cylinder block, which serves as an upper crankcase half for receiving a crankshaft in at least two camps and with a serving as a lower crankcase oil pan, which is provided for collecting and storing of engine oil, is connected on the side facing away from the cylinder head, wherein a pump is provided for conveying the engine oil via supply line to at least one consumer within the oil circuit.

In the present case, the oil supplied to the at least one consumer in the inlet-side coolant jacket, which is part of the oil circuit, is heated, which is advantageous in particular after a cold start and noticeably reduces the frictional loss of the internal combustion engine.

As already mentioned in the introduction, the at least one cylinder head and the cylinder block are connected to each other as part of the assembly at their mounting end faces, that is screwed together usually by means of threaded bolts. To seal the combustion chambers, a seal is often placed between the cylinder block and the cylinder head.

The cylinder block has a corresponding number of cylinder bores for receiving the pistons or the cylinder tubes. The piston of each cylinder is axially movably guided in a cylinder tube and defines together with the cylinder tube and the cylinder head the combustion chamber of a cylinder. The piston head forms a part of the combustion chamber inner wall and seals together with the piston rings the combustion chamber against the cylinder block or the crankcase, so that no combustion gases or combustion air enter the crankcase and no oil enters the combustion chamber.

The piston serves to transfer the gas forces generated by the combustion to the crankshaft. For this purpose, the piston is articulated by means of a piston pin with a connecting rod, which in turn is movably mounted on the crankshaft.

The crankshaft mounted in the crankcase receives the connecting rod forces, wherein the oscillating stroke movement of the piston is transformed into a rotating rotational movement of the crankshaft. A part of the energy transmitted to the crankshaft is generally used to drive auxiliary equipment such as the oil pump and the alternator or serves to drive the camshaft and thus the actuation of the valve train.

In general, and in the context of the present invention, the upper crankcase half is formed by the cylinder block. The crankcase is supplemented by the lower half of the crankcase, which can be mounted on the upper crankcase half and serves as an oil sump. The oil pan is used to collect and store the engine oil and is part of the oil circuit. In addition, the oil pan serves as a heat exchanger for lowering the oil temperature at warmed up internal combustion engine. The oil contained in the oil sump is cooled by heat conduction and convection by means of air flow past the outside.

For receiving and supporting the crankshaft at least two bearings are provided in the crankcase. For this bearing or the bearing of the crankcase, what has been said in connection with the camshaft bearing applies analogously, for which reason reference is made to the corresponding explanations.

In this context, embodiments of the internal combustion engine in which the supply line opens into a main oil gallery from the channels to the are advantageous at least two bearings of the crankshaft to supply the at least two bearings with engine oil.

According to this embodiment, the bearings of the crankshaft are supplied with oil which is heated in the inlet-side coolant jacket, which significantly reduces the friction in the bearings and has an advantageous effect on the warm-up behavior of the internal combustion engine.

Embodiments of the internal combustion engine in which the supply line passes through the cylinder head upstream of the main oil gallery are advantageous, preferably through the inlet-side coolant jacket of the cylinder head.

The supply line of the oil circuit passes through the cylinder head or through the inlet-side coolant jacket before this line opens downstream into the main oil gallery. The oil is heated in the cylinder head and only then used to lubricate the bearings of the crankshaft. While the prior art engine oil flows from the main oil gallery to the cylinder head, in the present case, it is directed from the cylinder head to the main oil gallery, which reduces friction in the bearings and reduces fuel consumption.

Embodiments of the internal combustion engine in which the supply line of the oil circuit downstream of the pump first passes through the cylinder head before this supply line enters the cylinder block are advantageous.

This embodiment utilizes the fact that the cylinder head is subjected to high thermal loads, in particular thermally loaded higher than the cylinder block, so that the heating of the oil, i. the increase in the oil temperature at a flow through the cylinder head is more pronounced than when flowing through the cylinder block.

After a cold start, the cylinder head heats up faster due to the ongoing combustion processes, especially compared to the cylinder block. The embodiment in question, ie the proposed flow guide, ensures that the crankshaft bearings are supplied with preheated oil more quickly and, in particular, prevents the heat entering the cylinder head upstream of the cylinder block from being removed from the heat.

But can also be advantageous embodiments of the internal combustion engine, in which the supply line first through the cylinder block and then, d. H. downstream, passes through the cylinder head, preferably through the inlet side coolant jacket.

Embodiments of the internal combustion engine are advantageous in which the supply line leads from the inlet-side coolant jacket to the camshaft receptacle for supplying the camshaft bearing with oil.

Advantageous embodiments of the internal combustion engine, in which the at least one cylinder head is connected to a mounting end face with a cylinder block having at least one coolant jacket to form a liquid cooling.

In addition to the cylinder head and the cylinder block is a thermally highly loaded component, so it may be necessary or advantageous to equip the cylinder block to form a liquid cooling with a coolant jacket. This can be particularly advantageous if less temperature-resistant materials are to be used or in supercharged internal combustion engines, which are thermally stressed higher than naturally aspirated engines.

In internal combustion engines with a cylinder block, which has at least one coolant jacket to form a liquid cooling, embodiments are advantageous, for example, in which the at least one coolant jacket of the cylinder block belongs to the cooling water circuit. Water is characterized by a high heat capacity, which is why when using water as a coolant larger amounts of heat can be dissipated.

Water has - as already mentioned - compared to other coolants further the advantage that it is non-toxic, readily available and inexpensive.

In internal combustion engines with a cylinder block, which has at least one coolant jacket to form a liquid cooling, embodiments in which the at least one coolant jacket of the cylinder block belongs to the oil circuit may also be advantageous.

Compared to the use of water, oil as a coolant has the advantage that it is not corrosive, rather even offers corrosion protection and unlike water with - in particular moving - components can easily come into contact without the functioning of the engine would be at risk ,

In addition, oil is fed anyway via supply line through the cylinder block, d. H. supplied to the block to supply the consumers, in particular the crankshaft, with oil.

With the equipment of the cylinder block with a coolant jacket to form a liquid cooling using motor oil as a coolant, the heating of the oil during the warm-up phase can be further accelerated.

In internal combustion engines of the aforementioned type having a cylinder block which has at least one coolant jacket to form a liquid cooling, embodiments are advantageous in which the at least one coolant jacket of the cylinder block is arranged upstream of the at least one coolant jacket of the cylinder head.

However, embodiments in which the at least one coolant jacket of the cylinder block is arranged downstream of the at least one coolant jacket of the cylinder head may also be advantageous.

Which arrangement of the block and head or flow direction of the coolant is to be preferred depends on the individual case, in particular also on which coolant is used or on which cooling circuit the coolant jacket of the block belongs.

In internal combustion engines, in which the at least one cylinder head is connected to a mounting end face with a cylinder block and connects to each inlet opening a suction, embodiments are advantageous, which are characterized in that the at least one inlet side coolant jacket between the mounting end face and the at least one suction line is arranged.

According to this embodiment, the at least one inlet-side coolant jacket is located on the cylinder block facing side of the intake system. This leaves enough space on the side facing away from the block of the cylinder head, for example, to arrange a camshaft holder, and leads to a compact design.

In internal combustion engines, in which the at least one cylinder head is connected to a mounting end face with a cylinder block and connects to each outlet an exhaust pipe, embodiments are advantageous, which are characterized in that the at least one outlet-side coolant jacket between the mounting end face and the at least one exhaust pipe is arranged.

According to this embodiment, the at least one outlet-side coolant jacket lies on the side facing the cylinder block. This leaves enough space on the side facing away from the block of the cylinder head, for example, to arrange a camshaft holder, and leads to a compact design.

In internal combustion engines, in which the at least one cylinder head is connected to a mounting end face with a cylinder block and connects to each outlet an exhaust pipe, embodiments are advantageous, which are characterized in that at least two outlet-side coolant jackets are provided, with a lower coolant jacket between the mounting end face and the at least one exhaust pipe is arranged and an upper coolant jacket is arranged on the opposite side of the lower coolant jacket of the at least one exhaust pipe.

According to this embodiment, a first, lower coolant jacket is located on the cylinder block facing side of the Abgasabführsystems, while a second, upper coolant jacket is arranged on the side facing away from the cylinder block of Abgasabführsystems.

Particularly advantageous in this connection are embodiments in which at least one connection is provided between the lower coolant jacket and the upper coolant jacket, which serves for the passage of coolant. Preferably, the at least one compound lies on the side of the elbow facing away from the cylinders.

By providing a connection, a very efficient cooling can be formed, as they require thermally highly stressed internal combustion engines, such as supercharged internal combustion engines, which are equipped with an integrated exhaust manifold.

The cooling of the cylinder head can additionally and advantageously be improved by generating a pressure gradient between the upper and lower coolant jacket, whereby the speed in the at least one connection is increased, which leads to an increased heat transfer due to convection.

The lower and the upper coolant jacket can be connected to each other over their entire width or only in sections, i. over a portion of the coolant jackets. As a result, the flow velocity in the at least one compound can be influenced and thus the heat transfer by convection.

The at least one connection is preferably arranged adjacent to the region in which the exhaust pipes merge to form the overall exhaust gas line, wherein the distance between the at least one connection and the total exhaust gas line is preferably smaller than the diameter or half the diameter of a cylinder. The distance is determined by the distance between the outer wall of the entire exhaust line and the outer wall of the connection.

In internal combustion engines having at least two cylinders, embodiments are advantageous in which the exhaust gas lines of at least two cylinders merge within the cylinder head to form an integrated exhaust manifold to form an overall exhaust gas line.

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.

Leading the way is the integration of the exhaust manifold in the cylinder head. This measure also allows the densest possible packaging of the drive unit.

Embodiments of the cylinder head with, for example, four cylinders arranged in series, in which the exhaust pipes of the outer cylinder and the exhaust pipes of the inner cylinder are each combined to form an overall exhaust line, are also cylinder heads of the type in question.

But are advantageous embodiments of the head, in which the exhaust pipes of all cylinders of the cylinder head within the cylinder head into a single, d. H. common, total exhaust line are merged.

Advantageous embodiments of the internal combustion engine, in which each cylinder has at least two outlet openings for discharging the exhaust gases from the cylinder. During the expulsion of the exhaust gases in the context of the charge exchange, it is a primary goal, as quickly as possible to release the largest possible flow cross-sections, to ensure effective discharge of the exhaust gases, which is why the provision of more than one outlet opening is advantageous.

Embodiments in which first the exhaust gas lines of the at least two outlet openings of each cylinder merge to form a partial exhaust gas line associated with the cylinder before the partial exhaust gas lines of at least two cylinders merge to form an overall exhaust gas line are advantageous.

The total travel distance of all exhaust pipes is thereby further shortened. The gradual merging of the exhaust pipes to an overall exhaust line also contributes to a more compact, d. H. less voluminous design of the cylinder head and thus in particular to a weight reduction and more effective packaging in the engine compartment.

But can also be advantageous embodiments in which each cylinder has an outlet opening for discharging the exhaust gases from the cylinder.

Embodiments in which the internal combustion engine is a supercharged internal combustion engine, preferably an internal combustion engine charged by means of an exhaust gas turbocharger, are advantageous.

Fig. 1

in einer leicht angestellten Draufsicht die Sandkerne der im Zylinderkopf zur Ausbildung einer Flüssigkeitskühlung integrierten Kühlmittelmäntel einer ersten Ausführungsform der Brennkraftmaschine, und

Fig. 2

in einer Seitenansicht die in Figur 1 dargestellten Sandkerne mit Blick in Richtung Kurbelwellenlängsachse.

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

Fig. 1

in a slightly salaried plan view, the sand cores integrated in the cylinder head to form a liquid cooling coolant jackets a first embodiment of the internal combustion engine, and

Fig. 2

in a side view the in FIG. 1 shown sand cores with a view towards the crankshaft longitudinal axis.

FIG. 1 shows in a slightly salaried plan view, the sand cores 1, 7 of the coolant jackets 2, 8 of two separate coolant circuits, as they are integrated according to a first embodiment in the cylinder head of an internal combustion engine.

With the sand cores 1, 7 illustrated FIG. 1 also roughly the integrated in the finished cylinder head sections of the two cooling circuits, namely the corresponding coolant jackets 2, 8, which is why the sand cores 1, 7 and the reference numerals for the associated coolant jackets 2, 8 wear.

To form a liquid cooling two coolant shells 2a, 2b and the inlet side a coolant jacket 8 are arranged in the cylinder head outlet side, wherein the two The outlet-side coolant jackets 2a, 2b belong to a cooling water circuit and the inlet-side coolant jacket 8 is part of a separate oil circuit. The two coolant circuits, namely the cooling water circuit on the one hand and the cooling oil circuit on the other hand, are separated.

These are in the present case the sand cores 1, 7 of a cylinder head of a three-cylinder in-line engine, wherein each cylinder outlet side two exhaust ports for discharging the exhaust gases from the cylinders and inlet side two inlet ports for supplying fresh air to the cylinders, wherein each Outlet opening an exhaust pipe and connected to each inlet port an intake. The exhaust pipes of the three cylinders lead together within the cylinder head to form an integrated exhaust manifold to an overall exhaust line (not shown). The cylinder head is connected to a cylinder block at a mounting end.

According to FIG. 1 is the inlet-side coolant jacket 8 of the oil circuit between the mounting end face and the suction arranged. The outlet-side cooling water circuit comprises two outlet-side coolant jackets 2a, 2b, of which a lower coolant jacket 2a between the mounting end face and the integrated exhaust manifold is disposed and an upper coolant jacket 2b on the lower coolant jacket 2a opposite side of the exhaust manifold. Consequently, the manifold is located between the lower coolant jacket 2a and the upper coolant jacket 2b and is covered over a large area by these coolant jackets 2a, 2b. The cooling water circuit does not include an inlet side coolant jacket.

On the side facing away from the cylinders of the exhaust manifold, on which the entire exhaust line exits from the cylinder head, two connections 2c between the lower coolant jacket 2a and the upper coolant jacket 2b are provided, which serve for the passage of cooling water, wherein in the plan view FIG. 1 only one connection 2c is visible.

The two connections 2c are arranged adjacent to the overall exhaust gas line, ie to the region of the manifold at which the exhaust gas lines merge and the cylinder head is subjected to a particularly high thermal load.

To remove the sand cores 1, 7 after the casting of the cylinder head accesses are provided, which also serve as Sandkernstützen 3, 9 during the casting process. The accesses are closed after casting. Such accesses can, however, in principle also be used in the context of liquid cooling for the supply or removal of coolant to the coolant jackets or circuits.

The entrances to the outlet-side coolant shells 2a, 2b are provided in the region of the two connections 2c, via which the lower coolant jacket 2a and the upper coolant jacket 2b communicate with one another.

At the in FIG. 1 illustrated embodiment, cooling water flows 4 and cooling oil flows 10 are formed on the side facing the mounting end, which are aligned substantially parallel to the cylinder longitudinal axes. By contrast, the associated coolant outflows 5, 11 run essentially parallel to the crankshaft longitudinal axis. For venting the cooling water circuit is a vent line. 6

FIG. 2 shows in a side view the in FIG. 1 shown sand cores 1, 7 with a view towards the crankshaft longitudinal axis. 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.

Out FIG. 2 It can be seen that on the side facing the mounting end side two cooling water inflows 4 enter the lower coolant jacket 2a of the cooling water circuit and two cooling oil inflows 10 in the inlet side cooling jacket 8 of the oil circuit and that the inflows 4, 10 are substantially parallel to the cylinder longitudinal axes.

It can be clearly seen that the lower and the upper coolant jacket 2a, 2b are not connected to each other over the entire length of the covered by them bend. The vent line 6 extends in the highest portion of the cooling water circuit.

reference numeral

1

Sand core of the cooling water circuit

2

Coolant jacket of the cooling water circuit

2a

lower coolant jacket

2 B

Upper coolant jacket

2c

connection

3

Sand core support

4

cooling water supply

5

Cooling water drain

6

vent line

7

Sand core of the cooling oil circuit

8th

Coolant jacket of the cooling oil circuit

9

Sand core support

10

Kühlölzufluß

11

Cooling oil drain

Claims (14)

1. Internal combustion engine having at least one cylinder, comprising

   - at least one cylinder head, and

   - a liquid cooling arrangement which has at least two coolant jackets (2, 8) integrated in the cylinder head, with each cylinder having, at the outlet side, at least one outlet opening for discharging the exhaust gases, and at the inlet side, at least one inlet opening for the supply of fresh air, with, in the cylinder head, at least one coolant jacket (2) being arranged at the outlet side and at least one coolant jacket (8) being arranged at the inlet side, and with said at least two coolant jackets (2, 8) being separate from one another and belonging to different, separate coolant circuits,

   characterized in that

   - the at least one outlet-side coolant jacket (2) belongs to a cooling water circuit, whereas the at least one inlet-side coolant jacket (8) belongs to an oil circuit.
2. Internal combustion engine according to Claim 1, characterized in that the cooling water circuit does not comprise an inlet-side coolant jacket.
3. Internal combustion engine according to Claim 1 or 2, characterized in that the at least one cylinder head is connected, at an assembly end side, to a cylinder block which serves as an upper crankcase half for holding a crankshaft in at least two bearings and which, at the side facing away from the cylinder head, is connected to an oil pan which serves as a lower crankcase half and which is provided for collecting and storing engine oil, with a pump being provided for feeding the engine oil via a supply line to at least one consumer within the oil circuit.
4. Internal combustion engine according to Claim 3, characterized in that the supply line opens out into a main oil gallery from which ducts lead to the at least two bearings of the crankshaft in order to supply the at least two bearings with engine oil.
5. Internal combustion engine according to Claim 4, characterized in that, upstream of the main oil gallery, the supply line leads through the cylinder head.
6. Internal combustion engine according to one of Claims 3 to 5, characterized in that, downstream of the pump, the supply line of the oil circuit firstly leads through the cylinder head before said supply line enters into the cylinder block.
7. Internal combustion engine according to one of the claims, characterized in that the at least one cylinder head is connected, at an assembly end side, to a cylinder block which, to form a liquid cooling arrangement, has at least one coolant jacket.
8. Internal combustion engine according to one of the preceding claims having a cylinder block which, to form a liquid cooling arrangement, has at least one coolant jacket, characterized in that the at least one coolant jacket of the cylinder block belongs to the cooling water circuit.
9. Internal combustion engine according to one of Claims 1 to 7 having a cylinder block which, to form a liquid cooling arrangement, has at least one coolant jacket, characterized in that the at least one coolant jacket of the cylinder block belongs to the oil circuit.
10. Internal combustion engine according to Claim 8 or 9 having a cylinder block which, to form a liquid cooling arrangement, has at least one coolant jacket, characterized in that the at least one coolant jacket of the cylinder block is arranged upstream of the at least one coolant jacket of the cylinder head.
11. Internal combustion engine according to one of the preceding claims, in which the at least one cylinder head is connected, at an assembly end side, to a cylinder block and an intake line is connected to each inlet opening, characterized in that the at least one inlet-side coolant jacket (8) is arranged between the assembly end side and the at least one intake line.
12. Internal combustion engine according to one of the preceding claims, in which the at least one cylinder head is connected, at an assembly end side, to a cylinder block and an exhaust line is connected to each outlet opening, characterized in that the at least one outlet-side coolant jacket (2) is arranged between the assembly end side and the at least one exhaust line.
13. Internal combustion engine according to one of the preceding claims, in which the at least one cylinder head is connected, at an assembly end side, to a cylinder block and an exhaust line is connected to each outlet opening, characterized in that at least two outlet-side coolant jackets (2a, 2b) are provided, with a lower coolant jacket (2a) being arranged between the assembly end side and the at least one exhaust line, and with an upper coolant jacket (2b) being arranged on that side of the at least one exhaust line which is situated opposite the lower coolant jacket (2a).
14. Internal combustion engine according to one of the preceding claims, having at least two cylinders in which an exhaust line is connected to each outlet opening, characterized in that the exhaust lines of at least two cylinders merge to form an overall exhaust line within the cylinder head, so as to form an integrated exhaust manifold.

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