EP3201445B1 - Cooling system, and internal combustion engine comprising a cooling system of said type - Google Patents

Description

The invention relates to a cooling system and an internal combustion engine with such a cooling system.

A cooling system of the type discussed here ( EP 1 832 730 A2 ; DE 199 48 160 A1 ; JP 2012 092751 A ) usually has a coolant circuit through which a liquid coolant for absorbing heat from components to be cooled, for example an internal combustion engine, flows. When the coolant is being filled or topped up or if there are any leaks in such a cooling system, air pockets can occur, which have a disadvantageous effect on the cooling performance of the cooling system. For this purpose, it is provided in known cooling systems that a vent line is fluidly connected to a component to be cooled, which is supplied with coolant via a coolant line, for venting the component. The vent line is different from the coolant line and does not serve to supply coolant, but rather specifically to vent the component. The vent line is typically led to a bubble separator of the cooling system, into which a large number of different components of the vent lines usually open, or the vent line is led into an expansion tank for the coolant circuit, with the air in the bubble separator or the collecting tank being separated from the coolant can be. In order to reach the bubble separator or the expansion tank, long ventilation lines are required in any case for components that are arranged further away from them, and these must be laid in a complex manner, in particular on an internal combustion engine. This results in considerable construction, manufacturing, assembly and qualification costs as well as high development costs. Furthermore, the accessibility of such long lines cannot be guaranteed everywhere, which makes the assembly either complex and expensive or a potential reconstruction necessary. In order to make the ventilation lines less susceptible to vibrations and any breakage that may result from them, they must be held at regular intervals. In particular, this means that long ventilation lines are attached to various components, with tolerances must be compensated or a tolerance compensation that is not possible can lead to disruptions in a series assembly process. If the ventilation lines are installed under tension, this can lead to the lines breaking during operation. Another problem arises that it is often not possible to hold vent lines at desired locations because other components are in the way. Larger distances must then be overcome by the ventilation lines swinging freely. The susceptibility of the ventilation lines to vibrations increases with their freely vibrating length. Another problem arises that the various vent lines must be assigned to a central feed into a bubble separator or a compensating tank orifice plates, which ensure through different diameters that different pressure levels of the components to be vented are balanced. In some cases, orifices with a flow diameter of 1 mm or less must be used, resulting in high flow resistance and a risk of clogging, for example if particles are present in the coolant.

The invention is based on the object of creating a cooling system and an internal combustion engine with such a cooling system, the disadvantages mentioned not occurring.

The object is achieved in that the subject matter of independent claim 1 is created. Advantageous configurations result from the subclaims. The object is achieved in particular by creating a cooling system which has at least one first component to be cooled, into which a first coolant line opens, a first vent line different from the first coolant line being fluidly connected to the first component for venting the first component that the first vent line opens into a second coolant line, the second coolant line being designed as a coolant path in a second component to be cooled or alternatively the first vent line opens into the second coolant line outside a component to be cooled. The vent line emanating from the first component is therefore not routed to a central feed point such as an expansion tank or a bubble separator, but rather - in particular decentrally - into a second coolant line, so that the air discharged from the first component is conveyed through the second coolant line along the coolant circuit can be. Due to this decentralized configuration, the ventilation line can also be used, especially when it is remote Arrangement of the first component to be cooled can be made shorter by an expansion tank than if a central inlet point and a merging of several ventilation lines were provided. As a result, disadvantages associated with long ventilation lines - in particular of a structural nature and with regard to a mounting and susceptibility to vibration - at least largely - preferably completely - can be avoided. Furthermore, there is no longer any risk of confusion between panels. Rather, identical orifice diameters can be used for different ventilation lines, so that identical parts can be used. Since it is no longer necessary to equalize different pressure levels of a large number of components at a central inlet point, larger orifice diameters can also be selected so that the risk of clogging due to particles in the coolant is avoided.

The cooling system is preferably set up to use a liquid coolant. The term “liquid” here means in particular that the coolant is in a liquid state under the conditions prevailing in the cooling system, in particular the pressures and temperatures prevailing there during operation. In particular, the coolant is preferably in liquid form under normal conditions, ie in particular at 1013 mbar and 25 ° C. Such coolants preferably have a higher thermal capacity than, in particular, gaseous coolants. They can therefore transport larger amounts of heat with a smaller volume and / or mass flow and thus enable more efficient cooling. The cooling system is particularly preferably set up to use water, preferably as a mixture with at least one antifreeze agent - for example glycol - as the coolant. Water is characterized by a particularly high heat capacity. However, there is the problem that the heat capacity of a mixture of coolant and air present in a line section under consideration is reduced in comparison to pure coolant and thus the efficiency of the cooling is reduced. Furthermore, air cushions can form at geodetically high points of components to be cooled, which if necessary can significantly reduce a coolant flow or even bring it to a complete standstill. Therefore, to improve the cooling performance of such a cooling system, it is necessary to vent the components to be cooled.

A component to be cooled is understood in particular as a part, in particular a component or functional part, of a device that is to be cooled by means of the cooling system. In particular, it can be a part, component or functional part of a Act internal combustion engine, for example a turbine housing or a compressor housing of an exhaust gas turbocharger or a crankcase.

A coolant line is understood to mean, in particular, a line that is set up to guide coolant, namely to supply, pass through and / or discharge coolant to, through or from a component to be cooled for the purpose of cooling the component to be cooled. In this case, a coolant line is designed, in particular in terms of its cross section, in such a way that a component to be cooled can be flowed through with a mass or volume flow of coolant that is sufficient to cool it. Such a coolant line can be formed as a separate line from the component to be cooled but fluidly connected to it, but also as a coolant path within a component to be cooled, for example by a double-walled housing. Coolant lines are preferably arranged in such a way that effective and efficient coolant guidance - in particular with regard to pressure loss, flow velocity, cavitations, and other relevant conditions - is guaranteed to all components to be cooled.

A vent line is understood to mean, in particular, a line which is provided for venting a component to be cooled and in particular is set up to remove air or a coolant / air mixture from the component to be cooled. A coolant / air mixture discharged from the component to be cooled for the purpose of venting via the vent line is richer in air than a coolant / air mixture that may flow through a coolant line. For the purpose of efficient venting, the vent line is preferably arranged on the component to be cooled in such a way that it is essentially supplied with air, although it is particularly possible that coolant is entrained by air bubbles entering the vent line. As a result, air accumulates in the vent line, at least in comparison to the coolant line, and the coolant proportion of the mixture passed through the vent line is significantly lower than in the coolant line. Furthermore, since the vent line does not have to carry a mass or volume flow of the coolant that is sufficient to cool the component to be cooled, it preferably has a smaller cross section than the coolant line. Vent lines are preferably arranged on a component to be cooled in such a way that suitable pressure levels are achieved or maintained stay to ensure a flow of the coolant. Furthermore, the ventilation lines are preferably made as short as possible.

Venting is understood here in particular to mean that air is discharged from a coolant line assigned to a component to be cooled or from a coolant path of the same in order to improve the efficiency of cooling and the flow of coolant through the component to be cooled.

Ventilation lines are preferred, as far as possible, with an incline to ensure effective ventilation.

In particular, at least two lines are fluidly connected to the first component to be cooled, namely the first coolant line on the one hand, and the first vent line different from it and preferably also separate from it, in particular arranged separately, the coolant line being set up in contrast to the vent line, in order to supply the component to be cooled with a mass or volume flow of coolant that is sufficient to cool it, the vent line being set up to ensure venting of the first component. The component to be cooled is preferably also fluidly connected to a further coolant line - as a third line - via which coolant is discharged after it has flowed through the component to be cooled. The vent line is therefore in particular not used to remove coolant, but rather for venting, preferably solely for venting.

The vent line is preferably fluidly connected to a coolant path within the first component. Such a coolant path, which itself also represents a coolant line, is particularly preferably formed by a double-walled or multi-walled housing of the first component. Because the vent line opens into this coolant path, the first component can be vented very efficiently. The first vent line preferably branches off from the first component, in particular from the coolant path, or it starts from the first component to be cooled, preferably from the coolant path.

The first vent line opens - preferably downstream of the first component - into the second coolant line, the term "downstream" here particularly relating to the direction of flow of the air discharged from the first component. The air or that Air-rich coolant / air mixture is thus discharged from the first component along the first vent line and introduced into the second coolant line.

The second coolant line is preferably arranged downstream - in relation to a coolant circuit of the cooling system - the first coolant line. It is in particular possible that the second coolant line - as a third line - branches off from the first component to be cooled and / or is directly fluidly connected to this in order to discharge coolant from the first component to be cooled. Furthermore, it is possible that the second coolant line is not directly in fluid connection with the first component to be cooled, but is arranged fluidically in series downstream of the first component to be cooled in the coolant circuit of the cooling system. However, it is also possible for the second coolant line to be arranged parallel to the first coolant line in the cooling system, for example in a parallel cooling branch of the cooling system.

According to the invention it is further provided that the second coolant line is designed as a coolant path in a second component to be cooled. This means in particular that a second component to be cooled is provided, which has an integral coolant path, for example formed by a double-walled housing of the second component, as a second coolant line, the first vent line opening into this coolant path. The air discharged from the first component to be cooled can thus be guided back into the coolant circuit in the second component to be cooled and from there - possibly via further coolant lines - be transported on. In particular, when the first component and the second component are arranged adjacent to one another, the result is very short ventilation lines.

Alternatively, it is possible for the second coolant line to lead to the second component to be cooled, the first vent line opening into the second coolant line outside the second component to be cooled. An embodiment is therefore also possible in which the vent line opens into a coolant line which does not penetrate a component to be cooled, but rather leads, for example, to a component to be cooled or away from a component to be cooled. It is also possible for the second coolant line to lead to an expansion tank of the cooling system and in particular to be in direct fluid connection therewith. It is also possible for the second coolant line to close an air separator of the cooling system and in particular is directly fluidly connected to this.

According to the invention it is provided that the first component to be cooled is designed as a turbine housing of an exhaust gas turbocharger. The second component to be cooled is designed as a compressor housing of the exhaust gas turbocharger. A particularly short vent line can thus be provided which branches off from the first component, namely the turbine housing, and opens into the second component, namely the compressor housing immediately adjacent to the turbine housing.

It is also possible that the first component is designed as a crankcase of an internal combustion engine.

Since the comparatively short ventilation lines preferably provided in the cooling system are less susceptible to vibrations than longer ventilation lines, they can be made of solid materials, in particular of metal or a plastic. Steel can preferably also be used as the material.

The cooling system is preferably compact and in particular designed with the smallest possible number of preferably short vent lines.

The cooling system is preferably designed as a closed permanent ventilation system.

By arranging the air separator in or on a coolant line of the cooling system, the cooling system and the cooling system as a whole are vented permanently and continuously during operation. This means, in particular, that at any point in time during operation of the cooling system, the coolant flows to or through the at least one air separator and air components present in the coolant flow are preferably separated off.

The cooling system can work in a closed manner, in particular it can be designed as a closed permanent ventilation system, so that the separated air is preferably not released directly into an atmosphere, but in particular is stored in a collecting container. A closed cooling system enables one compared to an open one System higher pressure, so that a corresponding coolant has a higher boiling point, which in turn can increase a permissible coolant temperature.

According to a development of the invention, it is provided that when the cooling system is in operation, a first pressure prevails in the first coolant line, a second pressure prevailing in the second coolant line, the first pressure being greater than the second pressure. The coolant is preferably conveyed by pressure differences along the cooling system and in particular along a coolant circuit of the cooling system. In this case, a direction of flow of the coolant is predetermined, in particular, by different pressure levels within the cooling system. The fact that the pressure in the second coolant line is lower than the pressure in the first coolant line during operation of the cooling system ensures that the air removed from the first component to be cooled is conveyed away from the latter and fed into the second coolant line, so that a results in a defined flow direction during venting. The first component to be cooled is therefore vented, in particular, in a pressure-driven manner.

According to a development of the invention it is provided that the first coolant line has a first cross-sectional area, the first vent line having a second cross-sectional area, the first cross-sectional area being larger than the second cross-sectional area. This is advantageous because, as intended, the vent line is only intended to vent the first component to be cooled, while the first coolant line is provided to supply the first component to be cooled with a mass or volume flow of coolant sufficient to cool it. Correspondingly selected cross-sectional areas ensure that the various lines can meet their various requirements, and also that an excessive coolant flow is not undesirably conveyed along the ventilation line, which could otherwise result in the cooling system not functioning properly.

Alternatively or additionally, the second coolant line has a third cross-sectional area that is larger than the second cross-sectional area of the first vent line.

The first and / or the third cross-sectional area is / are preferably by a factor of at least 16, preferably from at least 16 to at most 400, preferably from at least 25 to at most 225, preferably from at least 36 to at most 100, preferably from at least 25 to at most 49, preferably from at least 25 to at most 36, larger than the second cross-sectional area. Correspondingly, it results that the first and / or the second coolant line has / have a first or third diameter or radius with a circular cross section, the first vent line - also with a circular cross section - having a second diameter or radius, the first and / or the third diameter or radius is / are greater than the second diameter or radius, namely preferably by a factor of at least 4, preferably up to at most 20, preferably from at least 5 to at most 15, preferably from at least 6 to at most 10, preferably from at least 5 to at most 7, particularly preferably from at least 5 to at most 6.

It is possible for the first cross-sectional area of the first coolant line and the third cross-sectional area of the second coolant line to be the same size; but it is also possible that they are of different sizes. In addition, they can have the same or different shape or geometry.

In an exemplary embodiment of the cooling system, a coolant line preferably has a line diameter of 40 mm or more. A vent line preferably has a line diameter of at least 5 mm to at most 10 mm, preferably of at least 6 mm to at most 8 mm, preferably of 7 mm.

In general, it can be seen that the cross section of a vent line is generally selected independently of the required coolant volume flow of a component to be cooled. On the contrary, the smallest possible pipe size is preferably used here in order to keep the coolant flow along the ventilation line low, since this cannot be used for cooling.

According to a further development of the invention it is provided that the first vent line is in fluid connection with the first component to be cooled at a connection point which is higher than that, that is, in particular geodetically above the opening of the first coolant line into the first component to be cooled. The term "geodetically above" here refers in particular to the fact that the force of gravity specifies an excellent direction, which is also referred to as the vertical direction, with a side of the cooling system facing the center of the earth as the geodetically below and a side facing away from the center of the earth is referred to as geodetically above. The fact that the connection point for the first vent line is geodetically arranged above the mouth of the first coolant line means in particular that it is arranged above the mouth of the first coolant line - viewed in the vertical direction. This ensures that air flowing into the first component through the first coolant line can rise upwards, whereby it can escape into the vent line above the opening point of the first coolant line. The connection point for the ventilation line is particularly preferably arranged at a geodetically highest point of the first component. This has the particular advantage that air in the first component collects at the geodetically highest point and can be discharged from there through the ventilation line. In particular, the formation of an air cushion at the geodetically highest point of the first component can be avoided.

It is possible that the first coolant line opens geodetically into the first component on an underside thereof. The coolant then flows within the first component to be cooled from bottom to top and - depending on the opening point of a coolant line discharging the coolant from the first component - back down again, or it is discharged at a location geodetically above the opening of the first coolant line the first component discharged.

The opening of the first vent line into the second coolant line can take place at a geodetically below or geodetically above location, in particular in a second component to be cooled. The advantage of a junction geodetically above in a coolant path of a second component to be cooled is that the air flowing into the coolant path then does not have to rise in the second component, but remains geodetically at the top and is preferably discharged again from the second component here by means of a further vent line can.

According to a further development of the invention, it is provided that the cooling system has an air separator which - with respect to the flow direction of the coolant - is arranged downstream of the opening of the first vent line into the second coolant line. The air separator is preferably arranged in particular fluidically in series with the second coolant line, the second coolant line either opening directly into the air separator, or the air separator downstream of the second Coolant line - viewed in the direction of flow of the coolant - is arranged. A second vent line is fluidly connected to the air separator. It is thus possible to separate air conveyed along the second coolant line by means of the air separator from coolant likewise conveyed along the second coolant line and to discharge it through the second vent line.

An air separator is understood to mean, in particular, a device which is set up to separate air comprised by a fluid flow from liquid components of the fluid flow. The air separator is set up in particular to feed the separated air to the second vent line and thus vent the coolant circuit of the cooling system. This is not opposed to the fact that in practice a complete separation of air and coolant in the air separator may not succeed, in particular liquid coolant can also get into the second ventilation line with the separated air. The air / coolant mixture conducted in the second vent line is in any case richer in air and less coolant than the coolant / air mixture flowing into the air separator. Correspondingly, a coolant / air mixture flowing downstream of the air separator in a coolant line coming from it is richer in coolant and has less air than the coolant / air mixture flowing into the air separator.

The air separator preferably has a separating means which is set up to separate air from a coolant flow passing through the air separator and to supply it to the second vent line. The separating means is preferably designed as a lip or lamella arranged in the coolant flow passing through the air separator. The lip or lamella is preferably arranged in such a way that it is flowed against by the air portion and the liquid coolant portion of the coolant flow in such a way that it is passed on a first side by the air portion and on a second side by the liquid coolant, so that the first Side of the lip or lamella separated air can be removed from the coolant circuit. The lip or lamella is arranged in particular on a geodetically upper side of the air separator and, starting there, protrudes into the coolant flow at an angle to and against the flow direction of the coolant. Above the lip or lamella, an opening is preferably provided in the air separator, into which the second vent line opens. In this way, air can be siphoned off from the coolant flow through the lip or lamella and fed to the second vent line.

The lip or lamella is preferably designed in the shape of a spoon, which results in a particularly good skimming effect for air. In particular, air fractions, which as a rule flow geodetically above, are skimmed off, so that these air fractions flowing above are diverted from the spoon-shaped lamella or lip on its first side, the coolant flowing towards the lip or lamella - if it collides with the lip or lamella - is thrown back by the spoon shape in a turbulent movement and washed past the second side of the lip or lamella.

The air separator is preferably integrated into a coolant line of the cooling system or directly in fluid connection with a coolant line, for example with the second coolant line. It is thus integrated into the coolant circuit. This also allows the cooling system to be made very compact.

The separating means of the air separator preferably has a material or consists of a material selected from a group consisting of aluminum, copper, steel, plastic, rubber, carbon, a metal alloy, and a composite material.

The cooling system preferably comprises a coolant circuit with coolant lines for conveying the coolant along the coolant circuit, at least one component to be cooled, a heat exchanger for cooling the coolant, the coolant flowing along the coolant circuit both through the at least one component to be cooled and through the heat exchanger, and at least one delivery device for delivering the coolant along the coolant circuit. The conveying device is preferably designed as a pump. In particular, the coolant is conveyed along the coolant circuit, preferably by generating different pressure levels in the coolant circuit and by conveying the coolant along pressure gradients.

The air separator is preferably arranged in an area of the coolant circuit that has a lower pressure level than the highest pressure level of the coolant circuit - in particular immediately downstream of the conveying device - particularly preferably in an area of the coolant circuit that has the lowest pressure level. It is then possible in a particularly efficient manner to discharge air through an ascending, second ventilation line which opens into the air separator.

According to one embodiment of the invention it is preferably provided that the opening of the first vent line into the second coolant line is arranged at a distance from the air separator in such a way that the air introduced into the second coolant line through the first vent line rises on the flow path to the air separator in the second coolant line and can collect in a geodetically upper area thereof. At the same time, the opening of the first vent line into the second coolant line is preferably provided as close as possible to the air separator, so that the air introduced into the second coolant line is guided along the coolant circuit over the shortest possible distance. The spacing of the mouth from the air separator also ensures that air already in the second coolant line is not swirled. At the same time, it is preferably ensured that the air is not introduced into a flow dead zone via the mouth of the first vent line in the second coolant line, since otherwise an air cushion could form at the location of the mouth.

According to a further development of the invention, it is provided that the second coolant line and / or the second vent line open into an expansion tank of the cooling system for coolant. This has the advantage that air introduced into the expansion tank via the second coolant line and / or the second vent line can rise in the expansion tank and be separated from the coolant.

An expansion tank is understood here in particular as a reservoir for the coolant, which is used to compensate for pressure and / or temperature fluctuations in the cooling system, in that coolant can be fed from the expansion tank into the coolant circuit or returned from the coolant circuit to the expansion tank. The expansion tank is preferably part of the coolant circuit.

An exemplary embodiment of the cooling system is preferred in which it has a coolant circuit with an expansion tank which, in particular, is part of the coolant circuit. The expansion tank is not itself a coolant line or a vent line. It is preferably in fluid connection with at least one coolant line and / or at least one vent line.

It is possible for the cooling system to have more than one first component to be cooled. Additionally or alternatively, it is possible for the cooling system to have more than one second component to be cooled. The cooling system preferably has a plurality of coolant lines and / or vent lines. It is possible that in addition to at least one vent line which opens into a further coolant line and / or another component to be cooled, at least one vent line is also provided which opens directly into the expansion tank. It is particularly possible that such a vent line does not have a direct fluid connection to the air separator. Furthermore, it is possible that a coolant line, into which a vent line opens, is connected to the air separator, another coolant line, into which a vent line opens, is connected to the expansion tank bypassing the air separator. A direct venting to the expansion tank can take place in particular from components to be cooled, which are arranged in greater spatial proximity to the expansion tank, while a venting of components to coolant lines or other components to be cooled can be used in particular for components that are spatially further from the Expansion tanks are arranged remotely. In this way, it is possible in particular to use short vent lines that are of a similar length for all components.

The cooling system proposed here is particularly suitable for use on various internal combustion engines and / or vehicles, since it avoids coordination work for a specific application, for example on a test bench, as well as associated development and / or construction work or corresponding development loops to reduce the formation of vibrations in the respective ventilation lines can be.

It is possible that the coolant freed from air fractions by the air separator is fed directly into the expansion tank. As an alternative or in addition, it is possible for such a coolant to be fed directly from the air separator to a component to be cooled without first passing through the expansion tank.

According to a development of the invention, it is provided that the second coolant line is arranged spatially closer to the expansion tank than the first component to be cooled. The air discharged from the first component is thus when fed into the second coolant line closer to the expansion tank, thus at the same time promoted along the pressure gradient to a lower pressure level.

According to a further development of the invention it is provided that the second component to be cooled is arranged spatially closer to the expansion tank than the first component to be cooled. The air discharged from the first component is thus conveyed closer to the expansion tank when it is fed into the second component, and thus at the same time along the pressure gradient to a lower pressure level.

It is possible that air discharged from the first component is fed to a second component, discharged from this in turn and then fed to a third component, and this can be continued until the air is finally fed to the air separator and / or the expansion tank. Alternatively, however, it is also possible that only one intermediate station in the form of the second component is provided for the air discharged from the first component, so that it is fed directly to the air separator and / or the expansion tank after passing through the second component.

Finally, the object is also achieved by creating an internal combustion engine which has a cooling system according to one of the exemplary embodiments described above. In connection with the internal combustion engine, there are in particular the advantages that have already been explained in connection with the cooling system.

The internal combustion engine is preferably designed as a reciprocating piston engine. It is possible that the internal combustion engine is set up to drive a passenger car, a truck or a commercial vehicle. In a preferred exemplary embodiment, the internal combustion engine is used to drive particularly heavy land or water vehicles, for example mining vehicles, trains, the internal combustion engine being used in a locomotive or a railcar, or ships. It is also possible to use the internal combustion engine to drive a vehicle used for defense, for example a tank. One embodiment of the internal combustion engine is preferably also used in a stationary manner, for example for the stationary energy supply in emergency power operation, continuous load operation or peak load operation, the internal combustion engine in this Case preferably drives a generator. Stationary use of the internal combustion engine to drive auxiliary units, for example fire pumps on drilling rigs, is also possible. It is also possible to use the internal combustion engine in the field of conveying fossil raw materials and, in particular, fuels, for example oil and / or gas. It is also possible to use the internal combustion engine in the industrial sector or in the construction sector, for example in a construction or construction machine, for example in a crane or an excavator. The internal combustion engine is preferably designed as a diesel engine, as a gasoline engine, as a gas engine for operation with natural gas, biogas, special gas or another suitable gas. In particular, if the internal combustion engine is designed as a gas engine, it is suitable for use in a block-type thermal power station for stationary energy generation.

Figur 1

eine schematische Darstellung eines ersten Ausführungsbeispiels einer Brennkraftmaschine mit einem Kühlsystem;

Figur 2

eine Darstellung eines zweiten Ausführungsbeispiels einer Brennkraftmaschine mit einem Kühlsystem;

Figur 3

eine Darstellung einer anderen Ansicht der Brennkraftmaschine gemäß Figur 2, und

Figur 4

eine Schnittdarstellung durch ein Ausführungsbeispiel eines Luftabscheiders eines Ausführungsbeispiels eines Kühlsystems.

The invention is explained in more detail below with reference to the drawing. Show:

Figure 1

a schematic representation of a first embodiment of an internal combustion engine with a cooling system;

Figure 2

a representation of a second embodiment of an internal combustion engine with a cooling system;

Figure 3

a representation of another view of the internal combustion engine according to Figure 2 , and

Figure 4

a sectional view through an embodiment of an air separator of an embodiment of a cooling system.

Fig. 1 shows a schematic representation of a first exemplary embodiment of an internal combustion engine 1 with a cooling system 3. The cooling system 3 has a first component 5 to be cooled, into which a first coolant line 7 opens. A first vent line 9 different from the first coolant line 7 is fluidly connected to the first component 5 for venting it. The first vent line 9 opens into a second coolant line 11.

Here, the second coolant line 11 is designed as a coolant path 13, which is designed in a second component 15 to be cooled, for example in the form of a double-walled housing of the second component 15.

Alternatively, it is also possible for the first vent line 9 to open into a coolant line of a coolant circuit 17 of the cooling system 3 outside a component to be cooled. This even represents a preferred embodiment, since then no further component is acted upon by the air vented from another component. However, if the geometrical distance of the component to be vented from a skimming component and / or an expansion tank of the cooling system 3 is too great, it is advantageous, with regard to vent lines that are as short as possible and less susceptible to vibration, to vent into another component that is to be cooled closer. If, on the other hand, the component to be vented is arranged in close proximity to an expansion tank, venting is preferably carried out directly into the expansion tank.

When the cooling system 3 is in operation, there is a first pressure in the first coolant line 7 that is greater than a second pressure that prevails in the second coolant line 11. The venting of the first component 5 is therefore in particular pressure-driven.

The first and / or the second coolant line 7, 11 preferably has / have a first cross-sectional area, the first vent line 9 having a second cross-sectional area, the first cross-sectional area being larger than the second cross-sectional area, preferably by a factor of at least 16, preferably to at most 400, preferably from at least 25 to at most 225, preferably from at least 36 to at most 100, preferably from at least 25 to at most 49, preferably from at least 25 to at most 36.

The cooling system 3 here has an air separator 19 which is arranged downstream of the opening of the first vent line 9 into the second coolant line 11. A second vent line 21 is fluidly connected to the air separator 19. The air separator 19 preferably has a separating means which is set up to separate air from a coolant flow passing through the air separator 19 and to feed it to the second vent line 21.

The second vent line 21 opens here into an expansion tank 23 of the cooling system 3 for coolant. The expansion tank 23 serves in particular to compensate for thermally caused volume fluctuations of the coolant in the coolant circuit 17, and as a bubble separator or separating device in which air rises and out of the coolant escape and can therefore be discharged from the coolant circuit 17. The cooling system 3 can be designed as an open system or also as a closed system, the air in the latter case not being discharged to the atmosphere, but rather being collected in the expansion tank 23.

In the Figure 1 The illustrated arrangement of the various components 5, 15 does not reflect their actual spatial arrangement on the internal combustion engine 1, but rather serves to explain the structure of the cooling system 3 and the coolant circuit 17. In particular, the second component 15 is preferably arranged in spatial proximity to the first component 5. Furthermore, the second component 15 is preferably arranged spatially closer to the expansion tank 23 than the first component 5.

The coolant circuit 17 of the cooling system 3 comprises in the exemplary embodiment according to FIG Figure 1 specifically, the following elements: A plurality of further coolant lines are all identified here with the reference symbol 25 in order to simplify the illustration. Furthermore, additional ventilation lines are provided, all of which are identified here with the reference numeral 27 for the sake of simplicity.

The coolant is conveyed along the coolant circuit 17 by means of a conveying device 29, which is designed as a pump. The coolant circuit 17 comprises, as components to be cooled, in particular a crankcase 31 of the internal combustion engine 1, a cylinder head 33 of the internal combustion engine 1, an exhaust line 35, a charge air cooler 37, an oil heat exchanger 39, and the already mentioned first component 5 to be cooled, which is designed here as a turbine housing 41 of an exhaust gas turbocharger 42, as well as the second component 15 to be cooled, which is designed here as a compressor housing 43 of the exhaust gas turbocharger 42.

In the exemplary embodiment shown here, the turbine housing 41 in particular is vented into the compressor housing 43 via the first vent line 9.

The coolant circuit 17 also has a coolant heat exchanger 45 for cooling the coolant.

It is now evident that certain components can be vented into other components, here in particular the turbine housing 41 into the compressor housing 43, which then into the second coolant line 11 vented air is transported on this and finally between the charge air cooler 37 and the air separator 19 is fed back into a further coolant line 25 leading to the air separator 19, the air then being separated from the coolant flow in the air separator 19 and via the second Vent line 21 is fed to the expansion tank 23.

Other components, which are in particular spatially closer to the air separator 19, are preferably vented directly into the coolant line 25, which is fluidly connected to the air separator 19, between the charge air cooler 37 and the air separator 19, without the vented air previously being passed through another component to be cooled to be led. This is the case, for example, with the charge air cooler 37 itself and with the crankcase 31. The vented air or the air / coolant mixture flowing along the vent line 27 is fed into the coolant line 25 upstream of the air separator 19 and at a distance from it, so that the air has time to rise in the coolant line 25 before the air separator 19 and is therefore particularly efficient to be deposited in the air separator 19.

Further components to be cooled, in particular those which are arranged in greater spatial proximity to the expansion tank 23, are vented directly into the expansion tank 23 via vent lines 27. This is also the case here in particular for the crankcase 31, for the exhaust gas line 35 and for the oil heat exchanger 39.

In general, the ventilation lines 9, 21, 27 are preferably routed in such a way that they are designed as short as possible so that they do not tend to oscillate. Furthermore, the number of ventilation lines 9, 21, 27 can be significantly reduced compared to known designs of a cooling system.

The expansion tank 23 is preferably arranged at a geodetically highest point of the cooling system 3 so that the air can rise to the expansion tank 23 through the vent lines 21, 27, preventing air from flowing back into the vent lines 21, 27.

It can also be seen that a further coolant line 25 branches off from the first component 5 to be cooled as a third line in order to flow through the first coolant line 7 To remove coolant supplied to cooling again from the component 5 to be cooled. It becomes clear that the first vent line 9 is neither used for supplying nor for removing coolant, but actually specifically for venting the first component 5. This does not contradict the fact that coolant entrained by the vented air may also be routed along the vent line 9 becomes. The air / coolant mixture routed along the first vent line 9 is in any case much richer in air and at the same time lower in coolant than a coolant / air mixture that may be removed from the first component 5 along the coolant line 25, if the coolant routed along this coolant line 25 is still air at all contains.

Fig. 2 shows a representation of a second exemplary embodiment of an internal combustion engine 1 with a cooling system 3. Identical and functionally identical elements are provided with the same reference symbols, so that reference is made to the preceding description. Two exhaust gas turbochargers 42.1, 42.2 each with a turbine housing 41.1, 41.2 as the first component 5.1, 5.2 to be cooled are provided here, these first components 5.1, 5.2 each passing through a very short, first vent line 9.1, 9.2 into a respective compressor housing 43.1, 43.2 must be vented. Also shown is a further vent line 27 through which a coolant line (not shown) of an exhaust line 35 is vented. The expansion tank 23 is also shown.

It is particularly clear here that the first vent lines 9.1, 9.2 are in fluid connection with the first components 5.1, 5.2 at connection points 47.1, 47.2, which are geodetically arranged above the openings (not shown here) of the first coolant lines (also not shown), in particular on a geodetic one highest point of the first components 5.1, 5.2. This enables a particularly efficient venting of the first components 5.1, 5.2. In general, ventilation lines are preferably arranged at geodetically upper, in particular geodetically highest points of components to be vented.

Fig. 3 shows a representation of the embodiment of the internal combustion engine 1 with the cooling system 3 according to FIG Figure 2 from a different perspective and with an enlarged detail D. Identical and functionally identical elements are provided with the same reference numerals, so that in this respect reference is made to the preceding description. Here, in particular, ventilation lines 27 branching off from a crankcase 31 are shown, which upstream of an air separator 19 into a coolant line 25 opening into this open out, so that the air vented from the crankcase 31 is fed to the air separator 19 through the coolant line 25. It can then be separated from the coolant in the air separator 19 and fed to the collecting container 23 through the second vent line 21.

Further vent lines 27 are also shown, which lead from other components to be cooled directly into the collecting container 23. For example, a ventilation line 27 leads from the oil heat exchanger 39 directly into the collecting container 23.

A comparison of the Figures 2 and 3 shows in particular that the crankcase 31 is arranged closer to the air separator 19 than the turbine housings 41.1, 41.2 as the first components 5.1, 5.2 to be vented. It is therefore advantageous to vent the crankcase 31 directly into a coolant line 25 opening into the air separator 19, while the turbine housings 41.1, 41.2 are first vented into the compressor housings 43.1, 43.2. This means that the shortest possible and as few ventilation lines as possible can be used everywhere.

Fig. 4 shows an embodiment of the air separator 19. This has a separator 49, which is designed here as a lamella. Identical and functionally identical elements are provided with the same reference symbols, so that in this respect reference is made to the preceding description. The separating means 49 is set up to branch off air from a coolant flow passing through the air separator 19 along an arrow P and to supply it to the second vent line 21, which is shown here in the form of an orifice hole in the air separator 19. Accordingly, a part 51 of the air separator 19 arranged downstream of the separating means 49 carries little or even no air, so that an efficient cooling of a component to be cooled is achieved downstream of the air separator 19.

Air encompassed by the coolant accumulates geodetically at the top on its way through the air separator 19 and also previously through a coolant line 25 connected to it, in particular on a geodetically upper, first side 53 of the separating means 49. The air therefore always flows to the separating means 49 in such a way that it is passed along the first side 53 into the second ventilation line 21 and is discharged from there. In contrast, the coolant flows along a geodetically lower, second side 55 of the separating means 49 through the Air separator 19 and in particular through the part 51 arranged downstream of the separating means 49 further along the coolant circuit.

It is possible that the air separator 19 is preferably arranged directly upstream of the coolant heat exchanger 45.

Overall, it can be seen that by means of the cooling system 3 and the internal combustion engine 1 proposed here, very efficient cooling is possible while avoiding long and vibration-prone ventilation lines with optimized ventilation.

Claims (8)

1. A cooling system (3) comprising

   - at least one first component (5), which is to be cooled and into which a first coolant line (7) opens, wherein

   - a first ventilation line (9) is fluidically connected to the first component (5) for ventilating the first component (5) in such a way that

   - the first ventilation line (9) opens into a second coolant line (11), wherein

   - the second coolant line (11) is formed as coolant path (13) in a second component (15), which is to be cooled, or wherein

   - the second coolant line (11) leads to the second component (15), wherein the first ventilation line (9) opens into the second coolant line (11) outside of the second component (15),
   characterized in that

   - the first component (5) is formed as turbine housing (41) of an exhaust-gas turbocharger (42), wherein the second component (15) is formed as compressor housing (43) of the exhaust-gas turbocharger (42).
2. The cooling system (3) according to any one of the preceding claims, characterized in that a first pressure prevails in the first coolant line (7) during operation of the cooling system (3), wherein a second pressure prevails in the second coolant line (11), wherein the first pressure is higher than the second pressure.
3. The cooling system (3) according to any one of the preceding claims, characterized in that the first coolant line (7) has a first cross-sectional surface, wherein the first ventilation line (9) has a second cross-sectional surface, wherein the first cross-sectional surface is larger than the second cross-sectional surface, preferably by a factor of at least 16, preferably up to maximally 400, preferably of at least 25 to maximally 225, preferably of at least 36 to maximally 100.
4. The cooling system (3) according to any one of the preceding claims, characterized in that the first ventilation line (9) is fluidically connected to the first component (5) at a connection point (47), which is arranged higher than the opening of the first coolant line (7) into the first component (5).
5. The cooling system (3) according to any one of the preceding claims, characterized in that the cooling system (3) has an air separator (19), which is arranged downstream from the opening of the first ventilation line (9) into the second coolant line (11), wherein a second ventilation line (21) is fluidically connected to the air separator (19), wherein the air separator (19) preferably has a separating means (49), which is set up to separate air from a coolant flow permeating the air separator (19) and to supply said air to the second ventilation line (21).
6. The cooling system (3) according to any one of the preceding claims, characterized in that the second coolant line (11) and/or the second ventilation line (21) open into a compensation tank (23) of the cooling system (3) for coolant.
7. The cooling system (3) according to any one of the preceding claims, characterized in that the second coolant line (11) is arranged spatially closer to the compensation tank (23) than the first component (5).
8. An internal combustion engine (1), comprising a cooling system (3) according to any one of claims 1 to 7.

Images