DE102022108526A1 - Engine system - Google Patents

Abstract

The invention relates to an engine system (1), comprising an internal combustion engine (2), an intake tract (3) with a valve arrangement (10), an exhaust tract (20) and a return line (22) connecting the exhaust tract (20) with the intake tract (3). ). In order to optimize the temperature control of the gas flow in a supercharged engine with exhaust gas recirculation, the valve arrangement (10) is adjustable between a first state (A) and a second state (B), in which an at least switchable switching compressor (15) and an intake air cooler (16) is arranged downstream of the return line (22) in the intake tract (3), wherein in the first state (A) the intake air cooler (16) is arranged upstream of the switching compressor (15), while in the second state (B) the intake air cooler (16) is arranged downstream of the switching compressor (15).

Description

The invention relates to a motor system with the features of the preamble of claim 1.

Modern combustion engines require a sophisticated exhaust aftertreatment system to meet applicable emissions standards. In addition to a regular oxidation catalyst and a diesel particulate filter (DPF), such a system usually also contains a nitrogen oxide trap (Lean NOx Trap; LNT) and an SCR catalyst (Selective Catalytic Reduction). Apart from exhaust gas aftertreatment, exhaust gas recirculation (EGR) has established itself as an effective measure, namely to reduce the formation of nitrogen oxides in the exhaust gas. Some of the exhaust gases released during combustion are added to the fresh air sucked in, so that there is a reduced oxygen concentration during subsequent combustion. This ultimately leads to a reduced combustion temperature and therefore a reduction in the formation of nitrogen oxides, particularly in compression ignition engines such as diesel engines. In spark ignition engines such as gasoline engines, EGR can reduce fuel consumption at medium and high engine loads.

In addition to the internal EGR, in which the exhaust gas is sucked directly back into the cylinder, external EGR is particularly important in modern combustion engines and is used in both diesel and gasoline engines. Here, part of the exhaust gases from the exhaust tract are returned to the intake tract via a return line or EGR line. In order to further reduce the combustion temperature, an EGR cooler is often provided in the EGR line, which cools the recirculated exhaust gases. For turbocharged engines, a distinction can be made between high-pressure EGR and low-pressure EGR. In the former, the EGR line branches off from the exhaust line upstream of the turbine and flows into the intake line downstream of the compressor, while in the latter, the EGR line branches off from the exhaust line downstream of the turbine and flows into the intake line upstream of the compressor.

To meet future emissions and CO2 requirements, particularly for Real Drive Emission (RDE), tailpipe emissions must remain below a certain limit over a wide range of the engine map. This means expanding the use of EGR, combined with exhaust aftertreatment. In order to achieve sufficient conversion rates, the aftertreatment system must operate within a certain temperature window.

In turbocharged engines, an intercooler or intake air cooler is provided in the intake tract, which is necessary to ensure optimal engine efficiency at full load. In the case of exhaust gas recirculation, it also ensures that an optimal reduction in nitrogen oxides is achieved. To warm up the engine, the intake air cooler can be bypassed to increase the intake temperature so that the exhaust gas temperature can exceed the light-off temperature of the catalytic converter.

At high loads or full loads, it must be ensured that the exhaust gas temperature remains below an upper limit in order to ensure optimal functionality of the exhaust gas aftertreatment. The exhaust gas can be cooled, for example, by increasing the air mass flow through the engine. A high air mass flow can be achieved through high boost pressure. However, low-pressure EGR increases the temperature at the compressor outlet, which can easily lead to the temperature limits of the components behind the compressor being exceeded at high boost pressure.

Some engine systems have - usually in addition to a turbo compressor coupled to a turbine - an electric compressor or switchable mechanical compressor, which can be arranged either before or after the intake air cooler. A position in front of the intake air cooler is advantageous to keep the temperature in the intake manifold low. A position behind the intake air cooler, however, is advantageous in order to protect the compressor from high inlet temperatures.

In view of the state of the art shown, the optimal temperature control of the gas flow in a turbocharged engine with exhaust gas recirculation still offers room for improvement.

The invention is based on the object of optimizing the temperature control of the gas flow in a supercharged engine with exhaust gas recirculation.

According to the invention, the object is achieved by a motor system with the features of claim 1, the subclaims relating to advantageous embodiments of the invention.

It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically sensible manner and show further refinements of the invention. The description additionally characterizes and specifies the invention, particularly in connection with the figures.

The invention provides a motor system. The motor system is normally intended for motor vehicles such as trucks or cars, although an application for rail or watercraft, for example, would also be conceivable. The engine system has an internal combustion engine. The internal combustion engine (hereinafter also: engine) can in particular be a gasoline engine or a diesel engine, but neither the invention nor its advantages are limited to this.

Furthermore, the engine system has an intake tract (leading to the internal combustion engine) with a valve arrangement, an exhaust tract (leading from the internal combustion engine) and a return line connecting the exhaust tract with the intake tract. The intake tract, the exhaust tract and the return line serve to guide gases, preferably exhaust gases, and are therefore at least largely gas-tight. They can be completely or partially unbranched or branched. Furthermore, they can each be formed from one part or from several parts connected to one another. The intake tract serves to supply the internal combustion engine with fresh air, with the actual connection to the engine typically being provided by a branched intake manifold, which can be viewed as part of the intake tract. The intake tract has a valve arrangement that has at least one valve, usually a plurality of valves. Each valve can be designed to selectively block or completely or partially release a section of the intake tract. This also includes the possibility, for example in the manner of a directional control valve, of establishing different connections between sections of the intake tract or lines adjacent to the valve. The exhaust tract serves to remove exhaust gas from the internal combustion engine, with the connection to the engine typically being provided by a branched exhaust manifold, which can be viewed as part of the exhaust tract.

The return line, which can also be referred to as the exhaust gas recirculation line or EGR line, connects the exhaust tract with the intake tract and serves to add part of the exhaust gas to the fresh air sucked in so that they can mix in the intake tract or in the internal combustion engine. The objective can in particular be a reduction in the combustion temperature, which leads to a reduced formation of nitrogen oxides. The EGR line may have an EGR valve through which it can be blocked or fully or partially released. The exhaust gas in the exhaust tract and in the return line generally has a significantly higher temperature than fresh air drawn in from the environment. This circumstance is contrary to an intended reduction in the combustion temperature, which is why it may be desirable to cool the recirculated exhaust gas before it is fed to the intake tract and the internal combustion engine. For this purpose, the return line can have an exhaust gas recirculation cooler or EGR cooler, i.e. a heat exchanger, by means of which the recirculated exhaust gas can be cooled before it enters the intake tract.

According to the invention, the valve arrangement is adjustable between a first state and a second state, in which an at least switchable switching compressor and an intake air cooler are arranged downstream of the return line in the intake tract, wherein in the first state the intake air cooler is arranged upstream of the switching compressor, while in the second state the intake air cooler is arranged downstream of the switching compressor is arranged. The switching compressor is at least a switchable compressor. So it can at least be switched on and off, and the speed or power can also be adjusted. It can be, for example, a switchable mechanically operated compressor or preferably an electrical or electrically operated compressor (electric compressor). In any case, it is designed to compress gas (e.g. an air-exhaust gas mixture) within the intake tract. It can be powered as an electric compressor via a vehicle battery or, at least temporarily, via a generator that is coupled to the internal combustion engine. As a switchable mechanical compressor, it can be driven directly by the internal combustion engine (e.g. by its crankshaft), e.g. via chain, belt or gear transmission, with the switchability being achieved via an intermediate clutch. The intake air cooler is a heat exchanger that is designed to cool gas within the intake tract, for example by exchanging heat with a liquid cooling medium. The intake air cooler can also be referred to as an intercooler, especially if it is located downstream of a compressor within the intake tract. In this case, the gas compressed and thereby heated by the compressor can be cooled by the intake air cooler. Apart from compression, gas in the intake tract can also have an increased temperature due to the addition of exhaust gas from the return line. In this respect, the intake air cooler can complement the effect of an EGR cooler.

The valve arrangement can assume at least two states. In both states, the switching compressor and the intake air cooler are arranged in the intake tract downstream of the return line (or the point where the return line enters the intake tract). This means that exhaust gas from the return line inevitably comes together with air sucked in - through the switching compressor and the intake air cooler into the engine. Here and below, the terms “upstream” and “downstream” refer to the arrangement of the gas flow in the intended operating state of the engine system. The two states differ in the relative arrangement of the intake air cooler and switching compressor with respect to the gas flow in the intake tract. In the first state, the intake cooler is arranged upstream of the switching compressor, so that the gas flow first passes through the intake cooler, can be cooled there and is then compressed in the switching compressor. This can be advantageous when the engine has warmed up and has a high load (high torque), since the gas flow due to the recirculated exhaust gases can already have an increased temperature, which could be harmful to the switching compressor. This danger is eliminated by cooling in the intake air cooler. In the second state, the switching compressor is arranged in the intake tract in front of the intake air cooler, whereby the gas flow is cooled after it has passed through the switching compressor. This leads to particularly low temperatures when entering the engine or at an intake manifold that opens into the engine. This can generally be When the engine load is lower than in the first state, it makes sense if the focus is less on protecting components of the switching compressor and more on reducing nitrogen oxide emissions.

The different arrangements regarding the gas flow in the intake tract are only made possible by adjusting the valve arrangement. There is no restructuring of lines or sections of the intake tract. The valve arrangement is adjusted between the individual states, which means that at least one valve of the valve arrangement is adjusted. At least in some embodiments one can also speak of switching the valve arrangement or a valve. The adjustment is carried out effectively by actuators, i.e. via at least one actuator that is assigned to the valve arrangement. The respective actuator can be operated by a control unit, e.g. a motor control. The engine system according to the invention enables flexible adaptation according to the at least two states mentioned, although only a switching compressor and an intake air cooler are required, so that the number of components required is small and the required installation space also remains limited. In addition, the valve arrangement can be implemented with a comparatively small number of valves, which also contributes to a simple design and low costs.

In general, the engine system according to the invention can be used for different types of exhaust gas recirculation, for example for turbocharged engines with high-pressure or low-pressure EGR. The engine system advantageously has a turbine arranged in the exhaust tract and a turbo compressor mechanically coupled thereto, which in the first and second states is arranged upstream of the intake air cooler and the switching compressor. In contrast to the switching compressor, the turbo compressor is not driven electrically, but rather via a mechanical coupling through the turbine, which in turn is driven by the pressure of the exhaust gas in the exhaust tract. The turbo compressor is arranged upstream of the switching compressor in both the first and second states, so that a two-stage compression takes place. In the case of high-pressure exhaust gas recirculation, the return line branches off from the exhaust tract upstream of the turbine, i.e. in an area in which the exhaust gas has not yet released any energy to the turbine. The return line opens into the intake tract downstream of the turbo compressor, i.e. in an area in which the turbo compressor has already built up a (positive) overpressure. In contrast, with low-pressure exhaust gas recirculation, the return line branches off from the exhaust tract downstream of the turbine and opens into the intake tract upstream of the turbo compressor, i.e. in a low-pressure area.

The valve arrangement is preferably adjustable to a third state, in which the intake air cooler is integrated in the intake tract and the switching compressor is bypassed. As in the first and second states, the intake air cooler is arranged downstream of the return line, so that recirculated exhaust gas as well as sucked-in fresh air pass through the intake air cooler before they reach the engine. However, the switching compressor is bypassed in such a way that the gas flow through the intake tract is not led through the switching compressor. You could also say that the switching compressor is separated from the intake tract with regard to the gas flow. While the switching compressor is connected to the intake tract in the first and second states, at least one of these connections is separated in the third state, which of course relates to the possibility of a (significant) gas exchange. At least one valve of the valve arrangement blocks the connection between the switching compressor and the intake tract or its active areas, i.e. through which the gas flow flows. The third state can be assumed when the switching compressor is temporarily not needed and is deactivated. This can be the case, for example, with moderate loads and high speeds. In this case, bypassing the switching compressor can prevent unnecessary flow losses.

The valve arrangement can also be advantageously adjusted to a fourth state, in which the switching compressor is integrated in the intake tract and the intake air cooler is bypassed. The term “fourth” state does not mean that this embodiment is only possible or useful in combination with the third state mentioned above. Overall, the designation of the states only serves to differentiate and does not specify a chronological order or a ranking of the states. In the fourth state, the switching compressor is arranged downstream of the return line, as in the first and second states, so that recirculated exhaust gas as well as sucked-in fresh air pass through the switching compressor before reaching the engine. However, the intake air cooler is bypassed in such a way that the gas flow through the intake tract is not guided through the intake air cooler. This setting can be useful, for example, during a warm-up phase of the internal combustion engine or at low engine load and engine speed, ie in all situations in which the internal combustion engine and other parts of the engine system can have a rather low temperature. By bypassing the intake air cooler, different effects can be achieved, for example an increase in the exhaust gas temperature, which can help to activate exhaust gas aftertreatment components more quickly or to keep them active.

Furthermore, the valve arrangement can be adjustable to a fifth state, in which neither the switching compressor nor the intake air cooler is integrated in the intake tract, but both are bypassed. Here too, the term “fifth” state merely serves as a conceptual distinction and does not mean that this embodiment is only possible or useful in combination with the above-mentioned third or fourth state. In the fifth state, neither the switching compressor nor the intake air cooler is flowed through by the gas flow, i.e. both are bypassed. This can be advantageous, for example, if the switching compressor has internal water cooling. When starting the engine or when the internal combustion engine is cold and the cooling water is cold, this could lead to an undesirable cooling of the gas flow in the intake tract, which is avoided in the fifth state by bypassing the switching compressor (in addition to bypassing the intake air cooler).

The intake tract preferably has a compressor supply line leading to an inlet of the switching compressor and a cooler supply line leading to an inlet of the intake air cooler, which can alternatively be released by the valve arrangement. The compressor supply line is arranged (immediately) upstream of the switching compressor, so that a gas stream must flow through the compressor supply line in order to reach the inlet of the switching compressor and thus into the switching compressor. Accordingly, the cooler supply line is arranged upstream of the intake air cooler and must be passed through by the gas flow in order to reach the intake air cooler. The inlet of the switching compressor or the intake air cooler is the opening through which the gas flow enters during normal operation. The compressor supply line and the cooler supply line can be released alternatively or alternately by the valve arrangement, i.e. the valve arrangement is set up to release one supply line and at the same time block the other. However, this does not exclude the possibility that the valve arrangement can also release and/or block both supply lines at the same time. However, such a simultaneous blocking or releasing of both supply lines is not necessary and generally does not make sense.

The intake tract also preferably has a compressor discharge line leading from an output of the switching compressor and a cooler discharge line leading from an output of the intake air cooler, which can alternatively be released by the valve arrangement. The compressor discharge line is located (immediately) downstream of the switching compressor, so that a gas stream must flow through the compressor discharge line in order to exit through the output of the switching compressor. Accordingly, the cooler discharge line is arranged downstream of the intake air cooler and must be passed through by the gas stream so that it can exit the intake air cooler. The output of the switching compressor or the intake air cooler is the opening through which the gas flow exits during normal operation. The compressor discharge line and the cooler discharge line can be released alternatively by the valve arrangement, i.e. the valve arrangement is set up to release one discharge line and at the same time to block the other. However, this does not exclude the possibility that the valve arrangement can also release and/or block both discharge lines at the same time, although this is not necessary and generally does not make sense.

Furthermore, the intake tract advantageously has a first connecting line leading from the outlet of the intake air cooler to the inlet of the switching compressor and a second connecting line leading from the outlet of the switching compressor to the inlet of the intake air cooler, which can be released at least alternatively by the valve arrangement. The wording that a line “leads from a first point to a second point” does not imply here or below that a gas flow is only possible from the first to the second point. Basically, the reverse is also the case Direction possible. Ie the formulation means that the corresponding line connects the first and second points. Since the first connecting line connects the output of the intake air cooler with the input of the switching compressor, it is particularly important for the first state. Accordingly, the second connecting line, which connects the output of the switching compressor with the input of the intake air cooler, is particularly important for the second state in which the switching compressor is arranged upstream of the intake air cooler. The two connecting lines can be released at least alternatively by the valve arrangement, ie the valve arrangement can release at least one of the connecting lines while blocking the other. In addition, it would in principle be conceivable for the valve arrangement to be able to block and/or enable both connecting lines at the same time, although this is not necessary and generally does not make sense.

An embodiment of the invention provides that the valve arrangement has a first valve unit which is designed to release the cooler supply line in the first and third states and to release the compressor supply line in the second and fourth states. The term “valve unit” means here and below that this unit has at least one valve, possibly also a plurality of valves. However, the term should not be interpreted to mean that the valve unit as a whole must be physically coherent. For example, it could have a plurality of valves that are spatially separated but can be controlled in a coordinated manner. The first valve unit releases the cooler supply line in the first and third states (if this is provided), so that a direct flow of gas into the intake air cooler is possible. In the second and fourth states, however, the cooler supply line is blocked by the first valve unit, so that gas flow into the intake air cooler is not possible directly, but rather via a detour through the switching compressor. In the second and fourth states (if provided), the compressor supply line is released. In the first and third states, however, the first valve unit blocks the compressor supply line. In the first and third states, gas flow to the switching compressor is either prevented or only possible via a detour through the intake air cooler. In the second and fourth states, however, a direct flow of gas into the switching compressor is possible. With regard to the realization of the fifth state, there are two options in particular. A first option is to enable the compressor supply line, the cooler discharge line and the first connection line, while the cooler supply line, the compressor discharge line and the second connection line are blocked. A second option is to enable the cooler supply line, the compressor discharge line and the second connection line, while the compressor supply line, the cooler discharge line and the first connection line are blocked. In the case of the first option, the first valve unit is set up to release the compressor supply line and block the cooler supply line in the fifth state. In the case of the second option, the first valve unit is set up to release the cooler supply line and block the compressor supply line in the fifth state. You could also describe the second option as the sixth state, in which neither the switching compressor nor the intake air cooler is integrated into the intake tract, but both are bypassed.

A further embodiment provides that the valve arrangement has a second valve unit which is designed to release the compressor discharge line in the first and fourth states and to release the cooler discharge line in the second and third states. The second valve unit can release the compressor discharge line in the first and fourth states, provided the fourth state is provided. However, in the second and third states (if the latter is provided), the second valve unit blocks the compressor discharge line. In the second and third states, gas flow from the switching compressor to the engine is either prevented or only possible via a detour through the intake air cooler. In the first and fourth states, however, a direct flow of gas from the switching compressor to the engine is possible. On the other hand, in the second and third states, a direct gas flow from the intake air cooler to the engine is possible. In the first and fourth states, however, the cooler discharge line is blocked by the second valve unit, so that gas flow from the intake air cooler to the engine is not possible directly, but rather via a detour through the switching compressor. In the case of the above-mentioned first option, the second valve unit is set up to release the cooler discharge line and block the compressor discharge line in the fifth state. In the case of the second option, the first valve unit is set up to release the compressor discharge line and block the cooler discharge line in the fifth state.

Furthermore, it is preferred that the valve arrangement has a third valve unit which is designed to release the first connecting line in the first state and to release the second connecting line in the second state. Since the second connecting line connects the output of the switching compressor with the inlet of the intake air cooler, its release means that the gas flow runs from the switching compressor to the intake air cooler (and from there on to the engine). can. Accordingly, the release of the first connecting line, which connects the output of the intake air cooler with the input of the switching compressor, means that the gas flow can run from the intake air cooler to the switching compressor (and on to the engine). The third valve unit is preferably set up to block the second connecting line in the first state and to block the first connecting line in the second state. If these states are provided, the third valve unit can further be set up to block the first connecting line in the third state and to block the second connecting line in the fourth state. In the case of the first option mentioned above, the third valve unit is set up to release the first connecting line and block the second connecting line in the fifth state. In the case of the second option, the third valve unit is set up to release the second connecting line and block the first connecting line in the fifth state.

The valve arrangement preferably has the first, second and third valve units. In principle, embodiments are conceivable that have only one or two of the valve units described, without the numbering designating a specific preferred selection.

• 1 eine schematische Darstellung eines erfindungsgemäßen Motorsystems mit einer Ventilanordnung in einem ersten Zustand;
• 2 eine Darstellung des Motorsystems aus 1 mit der Ventilanordnung in einem zweiten Zustand;
• 3 eine Darstellung des Motorsystems aus 1 mit der Ventilanordnung in einem dritten Zustand;
• 4 eine Darstellung des Motorsystems aus 1 mit der Ventilanordnung in einem vierten Zustand;
• 5 eine Darstellung des Motorsystems aus 1 mit der Ventilanordnung in einem fünften Zustand; sowie
• 6 eine graphische Darstellung eines Motorkennfelds.

Further advantageous details and effects of the invention are explained in more detail below using an exemplary embodiment shown in the figures. Show it

• 1 a schematic representation of an engine system according to the invention with a valve arrangement in a first state;
• 2 a representation of the engine system 1 with the valve arrangement in a second state;
• 3 a representation of the engine system 1 with the valve arrangement in a third state;
• 4 a representation of the engine system 1 with the valve arrangement in a fourth state;
• 5 a representation of the engine system 1 with the valve arrangement in a fifth state; as well as
• 6 a graphical representation of an engine map.

In the different figures, the same parts are always provided with the same reference numbers, which is why they are usually only described once.

1-5 show an embodiment of an engine system 1 according to the invention, which in this case is part of the drive of a car. An internal combustion engine 2 is shown schematically. This is connected to an intake tract 3 for air supply and to an exhaust tract 20 for discharging exhaust gases. A turbo compressor 26 is arranged in the intake tract 3 and is mechanically coupled to a turbine 25 arranged in the exhaust tract 20 and thus through it can be driven. The turbine 25 can have a variable geometry. Furthermore, the exhaust tract 20 has an aftertreatment device 21 for exhaust gas (eg a diesel particulate filter), although of course a plurality of such aftertreatment devices 21 could be arranged one behind the other.

A return line 22 designed as a low-pressure return line branches off from the exhaust tract 20 downstream of the turbine 25 and opens into the intake tract 3 upstream of the compressor 26. It serves to return exhaust gas from the exhaust tract 20 to the intake tract 3. This measure reduces the combustion reaction rate in the internal combustion engine 2 and reduces the formation of nitrogen oxides. The amount of exhaust gas that flows through the return line 22 can be changed using a return valve 24. The return line 22 passes through an exhaust gas recirculation cooler 23, which can cool the exhaust gases removed from the exhaust tract 20 before they reach the intake tract 3. Optionally, a bypass line (not shown here) could also be provided to bypass the exhaust gas recirculation cooler 23. It would also be conceivable for the exhaust gas recirculation cooler 23 to be omitted. In this example, the return line 22 branches off from the exhaust gas tract 20 downstream of the aftertreatment device 21, but it could also branch off upstream of the same.

Downstream of the return line 22, the intake tract 3 has an electric compressor 15 serving as a switching compressor, an intake air cooler 16 and a valve arrangement 10 with three valve units 11-13. The valve units 11-13 are each shown schematically and can in reality be formed by one or more valves. Each valve unit 11-13, and thus the valve arrangement 10 as a whole, can be controlled by a control unit 30. The control unit 30 can be implemented, for example, by an engine control and decides on the setting of the valve arrangement depending on the current state of the internal combustion engine and other parameters. The switching compressor can be a mechanically operated compressor.

Downstream of the turbo compressor 26, the intake tract 3 branches off into one a compressor supply line 4 leading to an input 15.1 of the electric compressor 15 and a cooler supply line 5 leading to an input 16.1 of the intake air cooler 16. A first valve unit 11 is assigned to these supply lines 4, 5. Upstream of the internal combustion engine 2, the intake tract 3 has a compressor discharge line 6 leading from an output 15.2 of the electric compressor 15 and a cooler discharge line 7 leading from an output 16.2 of the intake air cooler 16. The two discharge lines 6, 7 can be at any point upstream of the Internal combustion engine 2 be merged. A second valve unit 12 is assigned to them. A first connecting line 8 leads from the output 16.2 of the intake air cooler 16 to the input 15.1 of the electric compressor 15, while a second connecting line 9 leads from the output 15.2 of the electric compressor 15 to the input 16.1 of the intake air cooler 16. A third valve unit 13 is assigned to the connecting lines 8, 9.

The valve arrangement 10 can assume at least five states AE. 1 shows a first state A. Here and below, sections through which the gas flow flows are shown in gray, while blocked or non-flow-through sections are shown in white. In this first state A, the cooler supply line 5 is released by the first valve unit 11, the compressor discharge line 6 is released by the second valve unit 12 and the first connecting line 8 is released by the third valve unit 13. In contrast, the compressor supply line 4, the cooler discharge line 7 and the second connecting line 9 are blocked. The intake air cooler 16 is thus arranged in the intake tract 3 upstream of the electric compressor 16. The gas flow guided in the intake tract 3, which consists either of air or of a mixture of air and recirculated exhaust gases, is first compressed in the turbo compressor 26 and then cooled in the intake air cooler 16 before it reaches the internal combustion engine 2 through the electric compressor 15. The first state A can be particularly advantageous when the internal combustion engine 2 has warmed up and is under high load, as in 6 is shown, which exemplifies the area of the engine map in which the individual states AD can be assumed, the engine speed N being plotted in a known manner as the abscissa and the torque M (i.e. the engine load) as the ordinate. Since at high load the gas flow can already have an increased temperature due to the compression in the turbo compressor 26 and possibly due to the recirculated exhaust gases, which could be harmful to the electric compressor 15, prior cooling makes sense.

2 shows a second state B. The compressor supply line 4 is released by the first valve unit 11, the cooler discharge line 7 is released by the second valve unit 12 and the second connecting line 9 is released by the third valve unit 13. In contrast, the cooler supply line 5, the compressor discharge line 6 and the first connecting line 8 are blocked. The electric compressor 15 is thus arranged in the intake tract 3 upstream of the intake air cooler 16. The gas flow guided in the intake tract 3 is first compressed in the turbo compressor 26 and then compressed again in a second stage in the electric compressor 15 before it is cooled in the intake air cooler 16 and reaches the internal combustion engine 2. As a result, the gas stream has a particularly low temperature when it enters the internal combustion engine 2. The second state B can be used, for example, at medium to high engine loads if the temperature of the gas stream is low enough, even without cooling, to pose no danger to the electric compressor 15.

3 shows a third state C. The cooler supply line 5 is released by the first valve unit 11, the cooler discharge line 7 is released by the second valve unit 12 and the second connecting line 9 is released by the third valve unit 13. The second connecting line 9 could also be blocked, but this is unnecessary. The compressor supply line 4, the compressor discharge line 6 and the first connecting line 8 are blocked. As a result, the intake air cooler 16 is integrated into the intake tract 3, while the electric compressor 15 is excluded or bypassed. The third state C can be selected when the electric compressor 15 is switched off and unnecessary flow losses can be prevented by bypassing it. This can be the case, for example, with moderate engine load or at high speed, as in 6 is shown.

4 shows a fourth state D. The compressor supply line 4 is released by the first valve unit 11, the compressor discharge line 6 is released by the second valve unit 12 and the first connecting line 8 is released by the third valve unit 13. The first connecting line 8 could also be blocked, but this is unnecessary. The cooler supply line 5, the cooler discharge line 7 and the second connecting line 9 are blocked. As a result, the electric compressor 15 is integrated into the intake tract 3, while the intake air cooler 16 is bypassed. As in 6 As can be seen, the fourth state D can be selected at low load and low speed or at a cold start in order to promote the warm-up phase of the engine system 1 by not cooling the intake air. With this setting of the valve arrangement 10, the electrocom can still be used if necessary pressors 15 possible, for example to supply the internal combustion engine 2 with sufficient oxygen for effective combustion.

5 shows the fifth state E. The compressor supply line 4 is released by the first valve unit 11, the cooler discharge line 7 is released by the second valve unit 12 and the first connecting line 8 is released by the third valve unit 13. In contrast, the cooler supply line 5, the compressor discharge line 6 and the second connecting line 9 are blocked. This means that neither the electric compressor 15 nor the intake air cooler 16 is flowed through, ie both are bypassed. This state can be advantageous, for example, if the electric compressor 15 has internal water cooling to protect components. Then, in the fifth state E, undesirable cooling of the intake air can be avoided when the engine is started or when the internal combustion engine 2 is cold and the cooling water is cold.

Alternatively, the fifth state E could also be realized in that the cooler supply line 5 is released by the first valve unit 11, the compressor discharge line 6 is released by the second valve unit 12 and the second connecting line 9 is released by the third valve unit 13, while the compressor supply line 4, the cooler discharge line 7 and the first connecting line 8 are blocked.

List of reference symbols:

1

Engine system

2

Internal combustion engine

3

intake tract

4

Cooler supply line

5

Compressor feed line

6

Radiator discharge line

7

Compressor discharge line

8, 9

connecting line

10

Valve arrangement

11-13

Valve unit

15

Electric compressor

15.1, 16.1

Entrance

15.2, 16.2

Exit

16

Intake air cooler

20

Exhaust tract

21

Aftertreatment device

22

return line

23

Return cooler

24

return valve

25

turbine

26

Turbo compressor

30

Control unit

A-E

Condition

Claims (10)

Motor system (1), comprising an internal combustion engine (2), an intake tract (3) with a valve arrangement (10), an exhaust tract (20) and a return line (22) connecting the exhaust tract (20) to the intake tract (3), characterized in that the valve arrangement (10) is adjustable between a first state (A) and a second state (B), in which an at least switchable switching compressor (15) and an intake air cooler (16) downstream of the return line (22) in the intake tract (3) are arranged, wherein in the first state (A) the intake air cooler (16) is arranged upstream of the switching compressor (15), while in the second state (B) the intake air cooler (16) is arranged downstream of the switching compressor (15). engine system Claim 1 , characterized in that the valve arrangement (10) can be adjusted to a third state (C), in which the intake air cooler (16) is integrated in the intake tract (3) and the switching compressor (15) is bypassed. Engine system according to one of the preceding claims, characterized in that the valve arrangement (10) can be adjusted to a fourth state (D), in which the switching compressor (15) is integrated in the intake tract (3) and the intake air cooler (16) is bypassed. Engine system according to one of the preceding claims, characterized in that the valve arrangement (10) can be adjusted to a fifth state (E), in which neither the switching compressor (15) nor the intake air cooler (16) is integrated in the intake tract (3), but both be bypassed. Engine system according to one of the preceding claims, characterized in that the intake tract (3) has a compressor supply line (4) leading to an inlet (15.1) of the switching compressor (15) and one leading to an inlet (16.1) of the intake air cooler (16). Cooler supply line (5), which can alternatively be released by the valve arrangement (10). Motor system according to one of the preceding claims, characterized in that the Intake tract (3) has a compressor discharge line (6) extending from an outlet (15.2) of the switching compressor (15) and a cooler discharge line (7) extending from an outlet (16.2) of the intake air cooler (16), which passes through the valve arrangement ( 10) can alternatively be released. Engine system according to one of the preceding claims, characterized in that the intake tract (3) has a first connecting line (8) leading from the outlet (16.2) of the intake air cooler (16) to the inlet (15.1) of the switching compressor (15) and one from the outlet (15.2 ) of the switching compressor (15) leading to the inlet (16.1) of the intake air cooler (16) second connecting line (9), which can be released at least alternatively by the valve arrangement (10). Engine system according to one of the preceding claims, characterized in that the valve arrangement (10) has a first valve unit (11) which is designed to release the compressor supply line (4) in the second (B) and fourth state (D) and the To release the cooler supply line (5) in the first (A) and third states (C). Engine system according to one of the preceding claims, characterized in that the valve arrangement (10) has a second valve unit (12) which is designed to release the compressor discharge line (6) in the first (A) and fourth states (D) and the To release the cooler discharge line (7) in the second (B) and third state (C). Motor system according to one of the preceding claims, characterized in that the valve arrangement (10) has a third valve unit (13) which is designed to release the first connecting line (8) in the first state (A) and the second connecting line (9) in to release the second state (B).

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