DE102022102641A1 - engine system - Google Patents

Abstract

The invention relates to an engine system (1), having an internal combustion engine (2) with at least one camshaft (7), an intake tract (10), an exhaust tract (11), a recirculation line (1) connecting the intake tract (10) to the exhaust tract (11). 15), and a recirculation valve (20), which has a first valve part (21) which can be driven about an axial valve axis (A) in such a way that the camshaft (7) has an integral speed ratio in relation thereto, through which a passageway (16) in the return line (15) and which has at least one tangentially delimited first passage opening (23) which can be temporarily at least partly arranged in the passageway (16) by rotating the first valve part (21). In order to enable efficient exhaust gas recirculation when the pressure conditions at the ends of the recirculation line change over time, the invention provides that the recirculation valve (20) has a second valve part (25) arranged adjacent to the first valve part (21) with a valve that can be arranged at least partially in the passageway (16). second through-opening (27), wherein a tangential position range of the first valve part (21), in which a first through-opening (23) overlaps with the second through-opening (27) in the through-path (16), is provided by adjusting the second valve part (25 ) is changeable.

Description

The invention relates to an engine system having the features of the preamble of claim 1.

Modern internal combustion engines require a highly developed exhaust aftertreatment system in order to meet the applicable emissions standards. In addition to a regular oxidation catalytic converter and a diesel particulate filter (DPF), such a system usually also contains a nitrogen oxide trap (Lean NOx Trap; LNT) and an SCR catalytic converter (Selective Catalytic Reduction). Apart from exhaust gas aftertreatment, exhaust gas recirculation (EGR) has established itself as an effective measure to reduce the formation of nitrogen oxides in the exhaust gas. Part of the exhaust gases that are released during combustion are added to the intake fresh air, 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 positive-ignition engines such as Otto engines, EGR can reduce fuel consumption at medium and high engine loads.

In addition to internal EGR, in which the exhaust gas is sucked back directly into the cylinder, external EGR, which is used in both diesel and gasoline engines, is particularly important in modern combustion engines. In this case, part of the exhaust gases from the exhaust tract is fed back into the intake tract via a recirculation 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. In supercharged 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 opens 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 opens into the intake line upstream of the compressor. While with low-pressure EGR there is usually a continuous pressure drop within the EGR line from the exhaust gas tract to the intake tract, this applies to high-pressure EGR - also depending on engine speed and torque - possibly only for part of the engine cycle. Outside this time window, the pressure drop is either too low to ensure effective recirculation, or is even inverted, i.e. the pressure in the intake tract (downstream of the compressor) is higher than in the exhaust tract (upstream of the turbine). This problem arises in particular with turbochargers with variable turbine geometry (VTG).

The DE 10 2018 107 436 A1 discloses an internal combustion engine with exhaust gas recirculation, with a recirculation valve for controlling the amount of exhaust gas to be recirculated into the fresh air line, the internal combustion engine being set up to activate the recirculation valve as a function of the combustion cycle. The engine control can be set up to bring the recirculation valve into specific positions depending on the camshaft position and/or the crankshaft position, in particular by means of a mechanical coupling element, such as at least one cam of a camshaft. A second valve can be provided, which can be controlled independently of the combustion cycle.

The JP 2005-054778 A shows an engine system in which an EGR gas inlet is provided to an EGR pipe in an exhaust pipe between an exhaust manifold plenum of a multi-cylinder engine and an exhaust gas inlet of a compressor. A rotary EGR valve is disposed in the EGR passage and rotated by a crankshaft. It is controlled to open at a timing when the peak pressure of the exhaust gas pulsation pressure is transmitted under engine operating conditions that are variable depending on a rotational phase changing device.

From the U.S. 4,165,721A there is known an exhaust gas recirculation system for an engine having a plurality of cylinders defining combustion chambers and intake and exhaust valves. There is further provided an exhaust gas mixer having at least one mixing chamber, conduit means connecting each of the combustion chambers separately to the mixing chamber, first valve means in the exhaust gas mixer operable to sequentially introduce an exhaust gas flow from each of the plurality of combustion chambers into the mixing chamber, wherein the exhaust gas mixer has an outlet port communicating with intake valves of the combustion chambers.

The KR 10 1180788 B1 discloses an exhaust gas recirculation valve for a vehicle, having an electric driving portion and a valve opening and closing portion. The valve opening and closing portion includes a gas inlet port on one side, a gas outlet port on the other side, a valve installation member, a valve sheet face, and a rotary valve. The valve installation member is formed between the gas inlet port and the gas outlet port. The valve sheet surface is formed at the upper and lower ends of the valve installation member and forms a stepped portion. The rotary valve is fixed to the upper and lower parts of the valve installation element. A direct current motor is mounted on the electric drive section to provide torque to the EGR valve.

The article "FEV BEAT - an innovative concept for the implementation of high-pressure EGR on the gasoline engine in the entire engine map" ( B. Franzke et al., Powertrain Expert Forum: Gas exchange and emissions 2020, pp. 25-45 ) discloses a concept for stroke-valve-controlled high-pressure EGR, in which the exhaust gas is only extracted in front of the turbine in the area of the pre-exhaust stroke. The thermodynamic potential is analyzed using gas exchange simulations on conventional 3- and 4-cylinder turbo engines and compared with conventional low- and high-pressure EGR technology.

In view of the state of the art shown, the implementation of an efficient exhaust gas recirculation with time-changing pressure conditions at the ends of the recirculation line certainly still offers room for improvement.

The object of the invention is to enable efficient exhaust gas recirculation with pressure conditions that change over time at the ends of the recirculation line.

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

It should be pointed out that the features and measures listed individually in the following description can be combined with one another in any technically meaningful way and show further refinements of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

An engine system is provided by the invention. The motor system is normally intended for motor vehicles such as trucks or cars, but an application for rail or water vehicles, for example, would also be conceivable. The engine system includes an internal combustion engine with at least one camshaft. The internal combustion engine (hereinafter also: engine) can in particular be an Otto engine or a diesel engine, but neither the invention nor its advantages are limited to this. The camshaft is used in a known manner to control at least one valve of a cylinder, usually a plurality of valves of cylinders of the internal combustion engine, via cams. It is possible within the scope of the invention that two camshafts are provided, one of which controls at least one intake valve and the other controls at least one exhaust valve. The at least one camshaft can be mechanically coupled to a crankshaft of the internal combustion engine in different ways, with a rotational speed of the crankshaft being twice the rotational speed of the camshaft.

Furthermore, the engine system has an intake tract (leading to the internal combustion engine), an exhaust tract (leaving from the internal combustion engine) and a recirculation line connecting the intake tract to the exhaust tract. The intake tract, the exhaust tract and the recirculation line serve to convey gases, preferably exhaust gases, and are therefore designed to be at least largely gas-tight. They can be unbranched or branched in whole or in sections. 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 regarded as part of the intake tract. The exhaust tract is used to discharge exhaust gas from the internal combustion engine, with the connection to the engine typically being provided by an equally branched exhaust manifold, which can be regarded as part of the exhaust tract. The recirculation 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 drawn in, so that they can mix in the intake tract or in the combustion engine. In particular, the aim can be a reduction in the combustion temperature, which leads to a reduced formation of nitrogen oxides.

In general, the engine system according to the invention can be used for different types of exhaust gas recirculation. In particular, it can be used in a supercharged internal combustion engine, advantageously for high-pressure exhaust gas recirculation. In a supercharged internal combustion engine, a turbocharger is provided, with a compressor being arranged in the intake tract and a turbine coupled to this being arranged in the exhaust tract. In the case of high-pressure exhaust gas recirculation, the recirculation 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 line downstream of the compressor, ie in an area in which the compressor has already built up a (positive) overpressure. In contrast, with low-pressure exhaust gas recirculation, the recirculation line branches off from the exhaust tract downstream of the turbine and opens into the intake tract upstream of the compressor, i.e. in a low-pressure area. The engine system according to the invention can be used particularly advantageously with a turbocharger with variable turbine geometry.

The engine system also has a recirculation valve, which can also be referred to as an EGR valve, EGR control valve or control valve. This has a first valve part which can be driven about an axial valve axis in such a way that the camshaft has an integral speed ratio in relation to it, through which a passageway in the return line can be blocked at least partially and which has at least one tangentially delimited first passage opening which can be opened by rotating the first valve part is temporarily at least partially arrangeable or arranged in the passageway. The valve axis, about which the first valve part can be rotated or is rotated, defines the axial direction and thus also implicitly the tangential and radial direction. The first valve part can be rotated about this valve axis, more precisely in a driven manner. The engine system is designed in such a way that there is a (positive) integer speed ratio between a speed of the camshaft and a speed of the first valve part. This means that the camshaft rotates either as fast as the first valve part or twice as fast, three times as fast, etc. In this respect, the speeds are linked to each other.

In the recirculation line, a passageway for exhaust gas is formed, which exhaust gas from the exhaust tract has to traverse in order to get into the intake tract. This passageway can be blocked or closed at least partially by the first valve part. A partial blockage means that part of the passageway for exhaust gas is blocked while another part is still permeable. The passage way is narrowed in this case. The first valve part has at least one first through-opening which is tangentially delimited, ie is limited to a specific angular range in the tangential direction. By rotating the first valve part, the first passage opening can be arranged or is arranged at least partially in the passageway at times. Said through hole, when placed in the passageway, allows passage of exhaust gas unless otherwise blocked. In this case, the through-opening is not continuous, corresponding to the rotation of the first valve part, but is only arranged intermittently in the through-path. It can also be said that rotation of the first valve part moves the first through opening (at least partially) in and out of the passageway.

According to the invention, the recirculation valve has a second valve part which is arranged adjacent to the first valve part and has a second through-opening which can be arranged or is arranged at least partially in the through-path, with a tangential position area of the first valve part, in which a first through-opening overlaps the second through-opening in the through-path, being provided by Adjusting the second valve part can be changed. The second valve part is arranged adjacent to the first valve part, typically in the direction in which the first through opening passes through the first valve part. In this respect, the second valve part can completely or partially prevent exhaust gas from passing through the first passage opening if it overlaps with the latter. However, it has a second through-opening which can be arranged at least partially in the through-path.

If the first and second passage openings in the passageway overlap, i.e. are aligned in the direction of passage, exhaust gas can pass through both passage openings, i.e. the passageway is open to this extent. In the course of the rotation of the first valve part, a tangential position range (i.e. an angular range with respect to the valve axis) of the same can be identified, in which there is a covering or overlapping of the two passage openings and the passageway is therefore open. In this state, exhaust gas can flow through the passageway. It goes without saying that the rotation of the first valve part should be coordinated with the rotation of the camshaft (and the associated opening of the at least one exhaust valve) such that the overlap coincides at least partially with a state in which there is a pressure drop in the recirculation line from the exhaust tract is given towards the intake tract. This is also the case, for example, with turbochargers with variable turbine geometry after an outlet valve has opened, which results in a temporary increase in pressure in the exhaust tract upstream of the turbine. The second valve part can be adjusted in such a way that the tangential position range in which the overlap occurs—and thus also the associated time interval—can be changed. In this way, just by adjusting the second valve part, the opening of the passageway can be delayed in time relative to the movement of the camshaft and the valves, i.e. it can be earlier or later depending on the setting of the second valve part. The first valve part can therefore rotate at a constant speed in relation to the camshaft. A possibly complicated control of the first valve part is therefore not necessary. On the other hand, a comparatively slight and/or slow adjustment of the second valve part may be sufficient to change the time interval of the overlap in the desired way.

It is conceivable within the scope of the invention that the first valve part rotates, for example, at half the speed of the camshaft or at a third of this speed.

Normally, however, it is preferred, particularly for design reasons, that the first valve part can be driven at the speed of the camshaft. That is, the rotational speeds of the first valve part and the camshaft agree with each other. Thus, after one rotation of the camshaft, a first passage opening again reaches the same position with respect to the passage, that is to say at a point in time at which the positions of the valves are also the same again.

In principle, different types of adjustment of the second valve part are possible. Since the tangential position range of the overlapping of the first and second passage opening in the passageway essentially depends on where the second passage opening in turn has an overlap with the passageway, it is advantageous if the tangential position of the second passage opening is adjustable. Accordingly, it is preferred that the second valve part can be adjusted by rotation about the valve axis. In this case, the second valve part moves tangentially during the adjustment and with it the second passage opening. By rotating the second valve part about the valve axis, the time interval of the overlap can be shifted forwards or backwards in time.

The first valve part is particularly preferably mechanically coupled to the internal combustion engine and is rotatable thereby. That is, the driving force for the first valve part is mechanically transmitted from the engine. This eliminates the need for a separate drive for the first valve part, which generally simplifies the design of the engine system and reduces costs. In addition, due to the mechanical coupling to the internal combustion engine, a specified speed ratio to the camshaft can be set without the need for sensors or electronic control elements.

In particular, the first valve part can be mechanically coupled to the camshaft. Here again, it is preferred that the first valve part is connected to the camshaft in a rotationally fixed manner. This includes the possibility that the camshaft is extended outside the engine housing so far that the first valve part touches down directly on it. Alternatively, however, a non-rotatable connection via a suitable coupling is also conceivable, in which the first valve part is seated on its own shaft. This configuration makes it possible to ensure in a simple manner that the first valve part rotates at the speed of the camshaft.

Different configurations of the valve parts and different arrangements of the passage openings are conceivable. For example, the through openings could be formed on cylindrical or conical lateral surfaces of the valve parts, which are each arranged symmetrically to the valve axis. A preferred embodiment provides that at least one first through-opening is formed in a first disk section of the first valve part oriented perpendicularly to the valve axis and the second through-opening is formed in a second disk section of the second valve part oriented perpendicularly to the valve axis. The two disc sections are normally flat and disc-shaped or plate-shaped, for example as circular discs, which are concentric to the valve axis. This applies in particular to the first disk section. The overall cross-section of each disc section is normally significantly larger than that of the passageway, with only a portion of the disc section protruding into the passageway.

The first valve part preferably has a blocking section which is offset tangentially to the at least one first passage opening and through which the passageway can be blocked independently of the position of the second valve part. The blocking section is therefore dimensioned such that it blocks the passageway when the first valve part is in a suitable tangential position, so that no gas flow or only a negligible gas flow is possible through the passageway, regardless of whether and to what extent the second passage opening is arranged in the passageway . This configuration ensures that the passageway can only be released when a first passage opening is arranged in the passageway. For optimal functioning of the engine system, the passageway should be completely closed in the meantime. If this is already ensured by the said blocking section of the first valve part, this means additional security, e.g. in the event of a non-optimal adjustment of the second valve part.

Normally, the internal combustion engine has a plurality of cylinders, it being advantageous if the recirculation line for each of the cylinders is opened, ie normally when the exhaust valve of the respective cylinder is opened. Accordingly, the first valve part can have a plurality of tangentially spaced first through openings. These can each be spaced apart from one another by a blocking section as described above. In particular the number of first through openings can correspond to the number of cylinders of the internal combustion engine. In the case of a three-cylinder engine, for example, three tangentially spaced first through openings are provided. If the speeds of the first valve part and the camshaft do not match, this also does not apply to the numbers of the first through openings and the cylinders. If, for example, the first valve part were to rotate at half the speed of the crankshaft, the number of first through openings would have to be twice as large as that of the cylinders. In order to achieve synchronization with all cylinders, the first through-openings are preferably distributed tangentially evenly, that is to say they have the same tangential offset in pairs (that is, 120° in the case of three through-openings). Since each through-opening has a tangential extension, the tangential distance between the through-openings is of course smaller than the tangential offset. So that there is an identical opening in the through-path for each cylinder, the first through-openings are preferably designed in the same way, ie their shape and size match.

The second valve part can preferably be adjusted by an electric motor. The electric motor can be designed as a direct current or alternating current motor. It can be a stepper motor, which allows the second valve part to be adjusted in discrete, even if possibly very small, steps. If the second valve part can be adjusted by rotating about the valve axis, this preferably also corresponds to an axis of rotation of the electric motor, the second valve part being connected in a torque-proof manner to a rotor of the electric motor. Alternatively, it would also be conceivable for the second valve part to be coupled indirectly to the electric motor, e.g. via a simple gear. The electric motor can be controlled by a control unit. Based on the current operating parameters of the internal combustion engine, this can determine an optimal setting for the second valve part.

A tangential extent of the second passage opening is advantageously smaller than a tangential extent of the passageway. I.e. the second passage opening does not completely fill the passageway in the tangential direction, but only partially. Thus, regardless of the shape and size of the first through-opening, only a part of the through-path can be released, the tangential position of which can be changed. The tangential position range in which the overlap occurs can be varied by positioning the second passage opening differently, although the size of the position range or the time duration of the overlap can be the same in each case.

Apart from adjusting the overlap and hence the point in time at which the passageway is opened, the second valve part can also be used to block the return line completely. According to one embodiment, the second valve part can be arranged or arranged in such a way that the passageway is blocked regardless of the position of the first valve part. This can be achieved, for example, by arranging the second through-opening outside of the through-path so that the first and second through-openings cannot overlap within the through-path. In this way, a specially provided valve for releasing and blocking the return line can be dispensed with, which simplifies the design of the engine system, is efficient and saves installation space.

The exhaust gas in the exhaust tract and in the recirculation line generally has a significantly higher temperature than fresh air sucked in from the environment. This circumstance in turn opposes the 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 thus to the internal combustion engine. An exhaust gas recirculation cooler can be provided for this purpose. In order to be able to regulate the cooling effected in this, a bypass line bypassing the exhaust gas recirculation cooler can branch off from the recirculation line and flow back into it, with at least one bypass valve being set up to influence a portion of the exhaust gas flow flowing through the bypass line. That part of the exhaust gas that flows through the bypass line is not additionally cooled by the exhaust gas recirculation cooler. Depending on the design and activation of the bypass valve, all or just a portion of the exhaust gas can be routed through the bypass at times. In the latter case, the uncooled exhaust gas from the bypass line in turn mixes with the cooled exhaust gas that has passed through the exhaust gas recirculation cooler, so that a mixed temperature is set overall.

• 1 eine schematische Darstellung eines erfindungsgemäßen Motorsystems;
• 2 eine Schnittdarstellung gemäß der Linie II-II in 1 gemäß einem ersten Zustand eines Rückführventils;
• 3 eine 2 entsprechende Schnittdarstellung gemäß einem zweiten Zustand eines Rückführventils;
• 4 eine 2 entsprechende Schnittdarstellung gemäß einem dritten Zustand eines Rückführventils;
• 5 eine 2 entsprechende Schnittdarstellung gemäß einem vierten Zustand eines Rückführventils; sowie
• 6 ein Diagramm, das einen zeitlichen Verlauf einer Druckdifferenz zeigt.

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

• 1 a schematic representation of an engine system according to the invention;
• 2 a sectional view according to the line II-II in 1 according to a first state of a recirculation valve;
• 3 one 2 corresponding sectional view according to a second state of a recirculation valve;
• 4 one 2 corresponding sectional view according to a third state of a recirculation valve;
• 5 one 2 corresponding sectional view according to a fourth state of a recirculation valve; as well as
• 6 a diagram that shows a time course of a pressure difference.

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 shows an embodiment of a motor system 1 according to the invention, which in this case belongs to the drive of a passenger car. An internal combustion engine 2 is shown schematically, in this case a diesel engine with three cylinders 3 in this example, in each of which a piston 4 is arranged, which is connected to a crankshaft 5 . In a manner not shown here, the crankshaft 5 is mechanically connected to two camshafts 7, only one of which is shown. This actuates three exhaust valves 6 via cams, each of which is assigned to a cylinder 3 . The internal combustion engine 2 is connected to an intake tract 10, in which a compressor 12 is arranged, and to an exhaust tract 11, in which a turbine 13 coupled to the compressor 12 is arranged. The turbine 13 can have a variable geometry, for example. Exhaust gases can escape from the cylinder 3 into the exhaust tract 11 by opening the exhaust valve 6 . Furthermore, the exhaust tract 11 has an after-treatment device 14 for exhaust gas, it being understood that a plurality of such after-treatment devices 14 could be arranged one behind the other.

A return line 15 designed as a high-pressure return line branches off from the exhaust tract 11 upstream of the turbine 13 and opens into the intake tract 10 downstream of the compressor 12 . It serves to return exhaust gas from the exhaust tract 11 to the intake tract 10 . This measure allows the combustion temperature in the cylinders 3 to be reduced and the formation of nitrogen oxides to be reduced. A recirculation valve 20 can be used to change the amount of exhaust gas that flows through the recirculation line 15 . Furthermore, the recirculation line 15 runs through an exhaust gas recirculation cooler 17. A bypass line 18 branches off from the low-pressure recirculation line 15 at a bypass valve 19 and bypasses the exhaust gas recirculation cooler 17. By adjusting the bypass valve 19, the ratio of exhaust gas which is cooled in the exhaust gas recirculation cooler 17 can be increased Exhaust gas, which flows uncooled through the bypass line 18, are adjusted. Under certain circumstances, both the exhaust gas recirculation cooler 17 and the bypass line 18 and the bypass valve 19 can be omitted.

Structure and function of the recirculation valve 20 are now including the 2-6 explained. The recirculation valve 20 is arranged on a passageway 16 of the recirculation line 15 which it can completely or partially block, so that an exhaust gas flow through the recirculation line 15 is prevented. A first valve part 21 is connected to the camshaft 7 in a torque-proof manner. The axis of rotation of the camshaft 7 forms a valve axis A, which defines an axial direction. The first valve part 21 has a substantially circular first disc section 22 which extends perpendicularly to the valve axis A. As in 2 As can be seen, it has three first through openings 23 which are offset tangentially by 120° to one another and between which a blocking section 24 is formed. A part of the first valve part 21 is in each case arranged in the passageway 16 , passage openings 23 and blocking sections 24 being alternately guided through the passageway 16 in accordance with the rotational movement of the camshaft 7 . A second valve part 25 is arranged along the valve axis A adjacent to the first valve part 21 and has a likewise essentially circular second disk section 26 . A second passage opening 27 is formed in this. The second valve part 25 can be rotated about the valve axis A, although it is not coupled to the camshaft 7 but to an electric motor 30 . This is controlled by a control unit 31 .

By adjusting the second valve part 25 by means of the electric motor 30, the position of the second passage opening 27 with respect to the passageway 16 can be changed. 2 and 3 12 show a state in which the second through hole 27 is located in a portion of the passageway 16 that is located forward with respect to a rotating direction R of the first valve member 21. FIG. In the course of the rotation, a first through-opening 23 and the second through-opening 27 within the through-path 16 therefore overlap relatively early.

2 shows a state in which the passageway 16 is still completely blocked by a blocking portion 24 while 3 shows a state in which for the first time there is a maximum overlap of a first through-opening 23 with the second through-opening 27 in the through-path 16, so that the through-opening 16 is open to the maximum. 6 illustrates the respective position of a first passage opening 23 in relation to the time course of the pressure difference Δp within the return line 15. A positive value of the pressure difference Δp indicates that there is a higher pressure on the side of the exhaust tract 11 than on the side of the intake tract 10. From 6 shows that the pressure difference is subject to strong fluctuations over time. Over large parts of the period under consideration, which corresponds to a complete rotation of the camshaft 7, there is a small or even negative pressure difference. Efficient exhaust gas recirculation is only possible during a comparatively short time interval when one of the exhaust valves 6 is opened. The arrangement of the first through-openings 23 is selected such that a first interval B, during which a first through-opening 23 is arranged entirely or partially in the through-path 16, coincides with the time interval of positive pressure difference. Accordingly 2 and 3 the second valve part 25 is adjusted so that a second interval C, during which a first through opening 23 and the second through opening 27 overlap each other within the through path 16, is at the beginning of the first interval B, ie comparatively early. The (time) interval C corresponds to the tangential position range of the first valve part 21 in which the overlapping of the first through-opening 23 with the second through-opening 27 is given.

Since a tangential extension of the second passage opening 27 is smaller than a tangential extension of the passageway 16, different positions of the second valve part 25 are possible, in which the second passage opening 27 is arranged completely within the passageway 16. 4 shows a condition similar 2 , although the second valve part 25 has been adjusted in such a way that the second passage opening 27 has been shifted rearward with respect to the direction of rotation R. This of course leads to the second interval C being shifted backwards in time.

5 shows a condition similar 2 and 4 . In this case, however, the second valve part 25 has been adjusted so far that the second passage opening 27 is no longer within the passageway 16 . Accordingly, the passageway 16 is permanently closed, regardless of the current position of the first valve part 21 . This setting can be selected when exhaust gas recirculation could be counterproductive.

The control unit 31 uses the current operating parameters of the internal combustion engine 2 to decide which setting of the second valve part 25 is currently optimal and sets it accordingly by means of the electric motor 30 .

Reference List

1

engine system

2

combustion engine

3

cylinder

4

Pistons

5

crankshaft

6

outlet valve

7

camshaft

10

intake tract

11

exhaust tract

12

compressor

13

turbine

14

aftertreatment device

15

return line

16

passageway

17

recirculation cooler

18

bypass line

19

bypass valve

20

recirculation valve

21

first valve part

22

first disc section

23

first passage opening

24

lockdown section

25

second valve part

26

second disc section

27

second passage opening

30

electric motor

31

control unit

A

valve axis

B, C

interval

R

direction of rotation

t

Time

Δp

pressure difference

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018107436 A1 [0004]
• JP2005054778A [0005]
• US4165721A [0006]
• KR 101180788 B1 [0007]

Non-patent Literature Cited

• B. Franzke et al., Expert Forum Powertrain: Gas exchange and emissions 2020, pp. 25-45 [0008]

Claims (10)

Engine system (1), having an internal combustion engine (2) with at least one camshaft (7), an intake tract (10), an exhaust tract (11), a recirculation line (15) connecting the intake tract (10) to the exhaust tract (11), and a recirculation valve (20), which has a first valve part (21) which can be driven about an axial valve axis (A) in such a way that the camshaft (7) has an integral speed ratio in relation thereto, through which a passageway (16) in the recirculation line ( 15) can be blocked at least partially and which has at least one tangentially delimited first passage opening (23) which can be temporarily at least partially arranged in the passageway (16) by rotating the first valve part (21), characterized in that the recirculation valve (20) has an adjacent second valve part (25) arranged for the first valve part (21) with a second passage opening (27) that can be arranged at least partially in the passageway (16), wherein a tangential position area of the first valve part (21) in which a covering of a first passage opening (23) with the second passage opening (27) in the passageway (16), can be changed by adjusting the second valve part (25). engine system after claim 1 , characterized in that the first valve part (21) can be driven at the speed of the camshaft (7). Motor system according to one of the preceding claims, characterized in that the second valve part (25) can be adjusted by rotation about the valve axis (A). Engine system according to one of the preceding claims, characterized in that the first valve part (21) is mechanically coupled to the internal combustion engine (2) and is rotatable thereby. Engine system according to one of the preceding claims, characterized in that the first valve part (21) is non-rotatably connected to the camshaft (7). Engine system according to one of the preceding claims, characterized in that the at least one first through-opening (23) is formed in a first disk section (22) of the first valve part (21) oriented perpendicularly to the valve axis (A) and the second through-opening (27) in a perpendicular to the valve axis (A) aligned second disc section (26) of the second valve part (25) is formed. Engine system according to one of the preceding claims, characterized in that the first valve part (21) has a plurality of tangentially spaced first through openings (23), the number of which corresponds to a number of cylinders (3) of the internal combustion engine (2). Motor system according to one of the preceding claims, characterized in that the second valve part (25) can be adjusted by an electric motor (30). Motor system according to one of the preceding claims, characterized in that a tangential extension of the second through-opening (27) is smaller than a tangential extension of the through-path (16). Engine system according to one of the preceding claims, characterized in that the second valve part (25) can be arranged in such a way that the passageway (16) is blocked independently of the position of the first valve part (21).

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