EP3133270A1

EP3133270A1 - Device for managing exhaust gas in an internal combustion engine

Info

Publication number: EP3133270A1
Application number: EP15382486.7A
Authority: EP
Inventors: Alvaro Sanchez Ragnarsson; José Antonio SANROMAN PRADO; Xoan Xosé Hermida Domínguez; Ignacio VIDAL
Original assignee: BorgWarner Emissions Systems Spain SL
Current assignee: BorgWarner Emissions Systems Spain SL
Priority date: 2015-10-06
Filing date: 2015-10-06
Publication date: 2017-02-22

Abstract

The present invention relates to a device for managing exhaust gas in an internal combustion engine suitable for making the entry of EGR gas (Exhaust Gas Recirculation) into the intake of the engine easier without requiring electronic control elements. Management is carried out by means of a mechanical linkage that establishes the throttle degree of the exhaust valve according to the opening degree of the EGR valve. Another object of this invention is also a compact module that contains the management elements as well as the heat exchanger.

Description

Object of the Invention

The present invention relates to a device for managing exhaust gas in an internal combustion engine suitable for making the entry of recirculated gas (EGR, Exhaust Gas Recirculation) into the intake of the engine easier without requiring electronic control elements in the linkage between the throttle of the exhaust valve and the opening of the EGR valve.
Management is carried out by means of a mechanical linkage that establishes the throttle degree of the exhaust valve according to the opening degree of the EGR valve.
Another object of this invention is also a compact module that contains the management elements as well as the heat exchanger.

Background of the Invention

The EGR system incorporated in an internal combustion engine is the assembly of devices and ducts responsible for reintroducing a given flow rate of exhaust gas in the intake of the engine to reduce the amount of oxygen entering the combustion chambers, and to thereby reduce nitrogen oxide formation.
The exhaust gas reintroduced in the intake of the engine is filtered to prevent the entry of dirt particles into the combustion chamber and other more sensitive elements such as the compressor, if one is present, and cooled to increase its density and so that it does not excessively affect the loss in efficiency due to reducing the fill level of the combustion chambers.
The proportion of fresh air taken from the atmosphere and of EGR gas is managed by a valve, the EGR valve. If the EGR valve is completely closed then the EGR system is canceled and all the intake air consists of fresh air. The EGR gas input is achieved by opening more or less the EGR valve incorporating a given percentage of exhaust gas into the intake gas. The maximum percentage of EGR gas is achieved with the complete opening of the EGR valve.
There are circumstances in which even with the maximum opening of the EGR valve, the EGR gas entering in the intake is insufficient because the EGR system has excessive pressure drop and the pressure of the EGR gas is not enough for entering in the intake.
In these cases a possible solution consists of increasing the pressure in the exhaust gas in order to overcome pressure drops in the EGR system. The increase in pressure of the exhaust gas is obtained by partially throttling the outlet of the exhaust gas into the atmosphere, although this throttle degree cannot be complete throttle since it would stop the engine.
There are complex management systems based on electronic devices controlled by control means opening or closing the exhaust valve according to the pressure requirements of the EGR gas at the intake.
These complex systems are expensive and subjected to the malfunctions that are characteristic of an electronic system and one that is furthermore managed by a computer system.
The present invention overcomes this lack of reliability and this high cost by means of a mechanical device that automatically manages the throttle requirements of the exhaust valve according to the opening of the EGR valve.

Description of the Invention

A first inventive aspect relates to a device cooperating with the management of the EGR gas in an EGR system. This device comprises:

a first EGR valve, comprising a first shaft with a first flap, wherein the rotation of the first flap determines the throttle degree of the passage through said first EGR valve; and wherein the first shaft can be operated by drive means;
a second exhaust valve, comprising a second shaft with a second flap, wherein the rotation of the second flap determines the throttle degree of the passage of said second exhaust valve; and wherein the second shaft can be operated by the first shaft by means of a mechanical linkage such that the opening of the first EGR valve establishes the partial closure of the second exhaust valve.

The device according to the present invention comprises both a first EGR valve to establish the throttle degree of the passage of EGR gas into the air supply of the internal combustion engine, and a second exhaust valve for throttling the exhaust gas to increase pressure in the exhaust duct.
Both valves are butterfly valves formed by a shaft and a flap integral with the shaft. The angle with which the shaft is positioned is what determines the throttle degree of the passage of gas through the valve.
The first EGR valve is operated by drive means acting on the shaft, determining its angular position, and thereby establishing the opening degree for the passage of EGR gas into the supply of the internal combustion engine.
A position in which the EGR system is not acted on consists of arranging the first EGR valve such that it is closed to prevent the entry of the EGR gas into the supply of the engine and the second exhaust valve such that it is open so as to not generate pressure losses in the exhaust duct. By taking these positions as reference positions, α will then refer to the opening angle of the first EGR valve and β will then refer to the throttle angle of the second exhaust valve.
According to the invention, between the first shaft, i.e., the shaft of the first EGR valve, and the second shaft, i.e., the shaft of the second exhaust valve, there is a mechanical linkage that determines the angular position β of the shaft of the second valve according to the angular position α of the shaft of the first EGR valve. In other words, a mechanical linkage is established which determines a ratio f that can be expressed as β=f(α).
Additionally and according to the invention, the first shaft of the first EGR valve and the second shaft of the second exhaust valve are parallel; and wherein the mechanical linkage between the first shaft and the second shaft comprises:

a drive component that can be operated by the first shaft comprising a first rotational attachment, where the drive component establishes the movement of said first rotational attachment;
a drag component integral with the second shaft comprising a second rotational attachment for operation;
a bar element joining the first rotational attachment and the second rotational attachment.

The mechanical linkage is a kinematic chain in which primarily three components act, i.e., the drive component, the drag component and the bar element connecting the drive component with the drag component.
The first drive component can be operated by means of the first shaft, and according to various embodiments that will be described below, it has a first rotational attachment that is moved according to the angular position of the first shaft. This first rotational attachment is what establishes the pushing or pulling on the bar element, which in turn moves the drag component also through its second rotational attachment.
The ratio β=f(α) depends not only on how the drive component and the drag component are configured, but also on the initial angular position of the three elements. Only by way of example, the rotation of the drag component about the second shaft due to the driving of the bar element, the motion of which is primarily linear, depends on the relative angle between the bar element and the connecting line extending between the second rotational attachment and the axis of rotation of the second shaft.
Given that the drag component is driven mechanically through a kinematic chain operated from the first shaft, said component does not require actuators that have to be controlled externally to establish the throttle degree of the second exhaust valve. This reduces the cost and the possibility of failures. Furthermore, the kinematic chain allows establishing complex ratios for ratio β=f(α) corresponding to optimal throttle requirements according to the flow rate of the EGR gas introduced in the intake engine.

Description of the Drawings

These and other features and advantages of the invention will become clearer from the following detailed description of a preferred embodiment given only by way of illustrative and non-limiting example, with reference to the attached drawings.

Figures 1A, 1B, 1C, 2A, 2B, 2C, 3A, 3B and 3C: These figures show a first embodiment of the invention in three possible positions of the EGR valve, where the drive component is a cam assembly. The bar element operates under pulling.
The first position is shown in Figures 1A-1C, the second position is shown in Figures 2A-2C and the third position is shown in Figures 3A-3C.
Figures 1A, 2A and 3A correspond to the front views showing the exhaust duct, making the flap of the exhaust valve visually accessible.
Figures 1B, 2B and 3B correspond to the top views which allow observing the position of the cam and the effect on the bar element and drag component of the exhaust valve.
Figures 1C, 2C and 3C correspond to a section of the previous plan views which allow observing the relative positions of the flaps of the EGR valve and of the exhaust valve for each of the three observed positions.
Figures 4A, 4B, 4C, 5A, 5B, 5C, 6A, 6B and 6C: These figures show a second embodiment of the invention in three possible positions of the EGR valve, where the drive component is a crank and the bar has a groove that delays actuation on the drag component. In this embodiment the bar element operates under compression (or under pushing).
The first position is shown in Figures 4A-4C, the second position is shown in Figures 5A-5C and the third position is shown in Figures 6A-6C.
Figures 4A, 5A and 6A correspond to the front views showing the exhaust duct making the flap of the exhaust valve visually accessible.
Figures 4B, 5B and 6B correspond to the top views which allow observing the position of the drive crank and the effect on the bar element and drag component of the exhaust valve.
Figures 4C, 5C and 6C correspond to a section of the previous top views which allow observing the relative positions of the flaps of the EGR valve and of the exhaust valve for each of the three observed positions.
Figures 7A, 7B, 8A, 8B, 9A and 9B: These figures show a third embodiment similar to the second embodiment, where the directions of rotation of the EGR valve and of the exhaust valve are opposite one another. The order of the views is the same as the order used in Figures 4A-6C. In this embodiment, the bar element operates under compression.
Figures 10A, 10B, 10C, 11A, 11B, 11C, 12A, 12B and 12C: These figures show a fourth embodiment similar to the second and third embodiment, where the directions of rotation of the EGR valve and of the exhaust valve are such that the bar element operates under pulling. The order of the views is the same as the order used in Figures 4A-6C.
Figures 13A, 13B, 14A, 14B, 15A and 15B: These figures show a fifth embodiment similar to the fourth embodiment, where the directions of rotation of the EGR valve and of the exhaust valve are opposite one another. The order of the views is the same as the order used in Figures 10A-12C. In this embodiment, the bar element also operates under pulling.
Figure 16: This figure shows a graph of a particular example of a function β=g(α) establishing the throttle requirements β of the exhaust valve according to the opening degree α of the EGR valve. Angles α and β are expressed as a percentage with respect to the minimum and maximum angle that each of the valves allows.

Detailed Description of the Invention

The present invention is a device for managing the exhaust gas of an internal combustion engine, where the pressure in the exhaust duct is established according to the opening degree of the EGR valve. Although the invention essentially comprises a first EGR valve and a second exhaust valve, throughout the description of the various embodiments use will be made of a more complete module including a heat exchanger, without said heat exchanger being essential for the invention.
Figures 1A-1C to Figures 15A-15B show five embodiments describing various configurations and combinations between the drive component that can be operated by the first shaft of the EGR valve, the drag component that in turn operates the second shaft of the exhaust valve, and the bar element linking them to one another. These five examples will not only show different configuration proposals for each of the components and the linkages established through the bar element, but they can also serve as a basis for a person skilled in the art for using each of them with additional combinations that can be applied to the remaining examples.
A plurality of embodiments of the invention is described in reference to the drawings, said embodiments being depicted by means of a device (1) for managing exhaust gas configured as a module. The module comprises a heat exchanger (8) for cooling EGR gas. Once the EGR gas flow is cooled by means of this heat exchanger device (8), it exits through a manifold guiding the gas to a first EGR valve (2). The first EGR valve (2) manages the flow rate of the EGR gas that is introduced in the intake inlet of the internal combustion engine to which the module is coupled being part of the EGR system of the engine.
The flow rate of the EGR gas introduced in the intake inlet of the engine depends on the pressure of the cooled EGR gas compared to the air pressure at the point of inlet of the intake in which the EGR gas is introduced. Although the exhaust duct in which the EGR gas is taken is at a higher pressure, the losses generated in elements such as filters or ducts, and the heat exchanger (8) cooling the EGR gas can be high and give rise to a pressure that is not enough for providing the required EGR gas even though the first EGR valve (2) is completely open.
To solve this problem, the present invention establishes a partial throttle of the exhaust duct which allows raising the pressure in the entire EGR system, and where this throttle is carried out by means of a kinematic chain with mechanical components that does not require any electronic management device, reducing the possibility of malfunctions as well as manufacturing cost.
In all the embodiments, the partial throttle is carried out by means of a second exhaust valve (3) located such that it is intercalated in the exhaust duct downstream of the point for collecting the EGR gas in said duct.
In all the embodiments, the first EGR valve (2) has a first flap (2.2) integral with a first shaft (2.1) such that the rotation of this first shaft (2.1) determines the angular position of the first flap (2.2) within the passage duct of the first EGR valve (2). In turn, the second exhaust valve (3) has a second flap (3.2) integral with a second shaft (3.1) such that the rotation of this second shaft (3.1) determines the angular position of the second flap (3.2) within the passage duct of the second exhaust valve (3).
In all the embodiments, the main axis of the internal duct of the first EGR valve (2) and the main axis of the internal duct of the second exhaust valve (3) are parallel.
The angular position of the first flap (2.2) establishes the opening degree of the first EGR valve (2), where in all the embodiments, there is a first end position completely closing the passage of the first EGR valve (2), and a second end position leaving the passage of said first EGR valve (2) completely open. The first end position in which the first EGR valve (2) is closed is shown in Figures 1, 4, 7, 10 and 13, and the second end position in which the first EGR valve (2) is open is shown in Figures 3, 6, 9, 12 and 15. Figures 2, 5, 8, 11 and 14 show an intermediate open position of the first EGR valve (2) which will be described below. Out of the three views used in some of the examples and each angular position, the letter "A" identifies an front view, the letter "B" identifies a top view, and the letter "C" shows the top view corresponding to letter "B" that has been sectioned in order to see the inside. The views corresponding to letters A and C allow observing the angular position of the first flap (2.2). The same order of the views associated with letters "A", "B" and "C" as well as the sequential order of the drawings will be used in all the embodiments to show the first end position of the first EGR valve (2), the intermediate position and the second end position of the same EGR valve (2). For the examples in which only two views are shown, the letter "A" identifies the top view and the letter "B" shows the top view corresponding to letter "A" that has been sectioned in order to see the inside, similarly to the previous examples in which three views were shown.
The angular position of the second flap (2.2) establishes the opening degree of the second exhaust valve (3), where in all the embodiments, there is a first end position leaving the passage of the second exhaust valve (3) completely open and a second end position in which, though shown in the drawings as leaving the passage of said second exhaust valve (3) completely throttled, throttle is partial or the flap has an opening or passage that prevents complete closure of the exhaust valve (3) from being established, preventing it from causing the internal combustion engine to stop.
As defined in the description of the invention, angle α will be used as the opening angle of the first EGR valve (2) and β as the throttle angle of the second exhaust valve (3).
According to the invention, between the first shaft, i.e., the shaft of the first EGR valve, and the second shaft, i.e., the shaft of the second exhaust valve, there is a mechanical linkage that determines the angular position β of the shaft of the second valve according to the angular position α of the first EGR valve. In other words, a mechanical linkage is established which determines a continuous ratio f that can be expressed as β=f(α).
According to this first embodiment, the kinematic chain linking the angular position α of the first flap (2.2) of the first EGR valve (2), its opening degree, with the angular position β of the second flap (3.2) of the second exhaust valve (3), its throttle degree, is by means of an assembly of elements that allows approximating a given ratio β=g(α), pre-established in the device design stage as it is considered to be optimal, by means of a ratio β=f(α) with a very high degree of accuracy. In other words, f is very close to g, and in most cases, and particularly according to this first embodiment, f can be equal to g.
Figures 1(A-C), 2(A-C) and 3(A-C) show this first embodiment. Drive means (4) act on the first shaft (2.1) of the first EGR valve (2). These drive means (4) are what determine the angular position of the flap (2.2) according to the EGR gas input requirements in the internal combustion engine.
The first shaft (2.1) extends out of the first EGR valve (2) and is integral with a cam (5.1.1) such that this cam (5.1.1) rotates together with the first shaft (2.1).
A guide (5.1.3) establishes a linear motion of a guided support element (5.1.4), which in this example is configured as a bar. At one end of the guided support element (5.1.4) there is a cam follower (5.1.2) establishing the position of the guided support element (5.1.4) along the longitudinal direction imposed by the guide (5.1.3).
The rotation of the first shaft (2.1), through the cam (5.1.1) - cam follower (5.1.2) assembly determines which linear movement is imposed to the guided support element (5.1.4) according to the angular position of the first shaft (2.1).
The assembly formed by the cam (5.1.1), the cam follower (5.1.2), the guide (5.1.3) and the guided support element (5.1.4) is identified as the drive component (5.1) in this embodiment and it is moved by means of the first shaft (2.1).
The end of the guided support element (5.1.4) opposite where the cam follower (5.1.2) is located shows a first rotational attachment (5.2).
The second shaft (3.1) of the exhaust valve (3) projects outwardly and is integral with a drag component (5.3) configured as a disc-shaped part. There is a second rotational attachment (5.4) at a point close to the periphery of the drag component (5.3). A bar element (5.5) extends between the first rotational attachment (5.2) and the second rotational attachment (5.4) such that the linear motion imposed by the drive component (5.1) on the first rotational attachment (5.2) is converted into a circular arc motion in the second rotational attachment (5.4).
In this embodiment, and applicable to other embodiments, the rotational attachments are formed by ball-and-socket joints that absorb, for example, a lack of parallelism between the first shaft (2.1) and the second shaft (3.1).
As a result, the rotation for opening the first flap (2.2) causes pulling on the bar element (5.5) and the latter in turn causes the rotation for throttling the second flap (3.2).
In this embodiment, although it can be applied to other embodiments, the bar element (5.5) comprises a regulating element (5.5.1) regulating the length thereof which, once manufactured and assembled, allows adjusting the relative rotation between the first flap (2.2) and the second flap (3.2).
In this embodiment, although it can be applied to other embodiments, the drag component (5.3) is linked with the rigid body of the exhaust valve (3) through a return spring (7) which provides a tendency that keeps the second flap (3.2) open.
In this embodiment, the configuration of the cam (5.1.1) is what determines the degree of linear movement of the cam follower (5.1.2), and therefore of the guided support element (5.1.4), according to the rotation angle α of the EGR valve (2).
Particularly in this embodiment, the cam (5.1.1) has a profile with a first circular arc angle segment without any variation of the radius, which gives rise to zero linear movement of the cam follower (5.1.2). This first segment allows starting to open the first EGR valve (2) without producing any throttle in the exhaust duct, avoiding the power losses this causes in the engine.
Figure 2B shows the intermediate position in which the first flap (2.2) has already carried out a first rotation angle, partially opening the first EGR valve (2) without having yet started throttling the second exhaust valve (3).
According to other embodiments not shown in the drawings, the profile of the cam (5.1.1) can be such that rather than generating a pull on the bar element (5.5), compression thereof is caused. In this case, the second rotational attachment (5.4) will be located on the other side of the drag component (5.3) with respect to a geometric line connecting the first rotational attachment (5.2) and the second shaft (3.1). This symmetrical configuration will be shown explicitly with later examples that are supported in the drawings.
Figures 4(A-C), 5(A-C) and 6(A-C) show a second embodiment, in which the kinematic chain forming a mechanical linkage (6) linking the rotation of the first shaft (2.1) and the rotation of the second shaft (3.1) has been modified with simpler and less expensive components.
In this embodiment, the drive component (6.1) is configured as a crank. The crank (6.1) is integral with the first shaft (2.1) in its outer prolongation, and the first rotational attachment (6.2) is located at its end.
In this second example, the drag component (6.3) has a configuration similar to the drag component (5.3) of the first embodiment, except the second rotational attachment (6.4) has been spaced from the position of the center of rotation of the second shaft (3.1) to a further extent by means of an arm. This larger distance allows reducing the rotation angle with which the second shaft (3.1) responds in response to a given rotation angle of the first shaft (2.1).
Like in the first embodiment, the second drag component (6.3) comprises a return spring (7) imparting a tendency on the second flap (3.2) to remain open.
The first rotational attachment (6.2) and the second rotational attachment (6.4) are connected by a bar element (6.5) which in this embodiment is configured from a die cut flat bar.
Discontinuous line X-X' shows a reference line connecting, in the top view projection, the first shaft (2.1) and the second shaft (3.1). In this embodiment, the first rotational attachment and the second rotational attachment are arranged on opposite sides with respect to this reference line X-X'. The rotation for opening the first flap (2.2) generates a compressive stress on the bar element (6.5) which in turn pushes on the second rotational attachment (6.4), causing the rotation in the second flap (3.2).
In this second embodiment, although it can be applied to other embodiments, one of the rotational attachments, i.e., the second rotational attachment (6.2), has a linkage established through a groove (6.6).
In a first segment of rotation of the first shaft (2.1), the movement of the bar element (6.5) causes the second rotational attachment (6.2) to move in the groove (6.6) without said bar element (6.5) causing the rotation of the second flap (3.2). This groove (6.6) allows defining a ratio between α and β such that, in the first interval of α, up to a given value α₀, β maintains its null value.
Between Figures 4(A-C) and Figures 5(A-C), it can be seen how the second flap (3.2) has not moved but the position of the second rotational attachment has gone from one end of the groove (6.6) to the other end of said groove (6.6). After this point, greater opening of the first flap (2.2) causes a throttle degree of the second flap (3.2), as shown by the end position depicted in Figures 6(A-C).
Figures 7(A-B), 8(A-B) and 9(A-B) show a third embodiment, where the first rotational attachment (6.2) and the second rotational attachment (6.4) are located on opposite sides with respect to reference line X-X' joining the first shaft (2.1) and the second shaft (3.1), and in a symmetrical configuration with respect to the second embodiment. In this third embodiment, the tendency of the return spring (7) must be in the also opposite rotational direction, and the bar element (6.5) likewise works under compression by applying a push on the second rotational attachment (6.4) to cause throttle of the second flap (3.2).
Figures 10(A-C), 11(A-C) and 12(A-C) show a fourth embodiment in which the bar element (6.5) works under pulling instead of compression. This embodiment shares the components of the second and third embodiments, but nevertheless, the initial position seen in Figure 10(A-C) of the second rotational attachment (6.4) with respect to the groove (6.6) is located at the end closest to the first rotational attachment (6.2). The rotation of the first shaft (2.1) pulls on the bar element (6.5), first making the second rotational attachment (6.4) slide in the groove (6.6) until reaching the end position, and the subsequent rotation of the first shaft (2.1) opening the first EGR valve (2) causes the throttle of the second exhaust valve (3).
In this fourth example, the angle formed by the crank (6.1) and the bar element (6.5) before rotation for opening the first flap (2.2) of the first EGR valve (2) starts is close to 90° instead of forming an acute angle, as occurs in the second and third embodiments. This initial angle between the crank (6.1) and the bar element (6.5), as well as the initial angle between the bar element (6.5) and the line connecting the second rotational attachment (6.4) and the axis of rotation of the second shaft (3.1), allows adjusting the degree of sensitivity between the throttle of the exhaust valve (3) and the opening of the EGR valve (2).
Figures 13(A-B), 14(A-B) and 15(A-B) show a fifth embodiment with a symmetrical configuration with respect to the fourth embodiment, similarly to how the third embodiment has a symmetrical configuration with respect to the second embodiment. In this embodiment, the bar element (6.5) also works under compression.
The use of a groove (6.6) in the bar element (6.5), either in the connection with the first rotational attachment or in the connection with the second rotational attachment, so that an initial rotation angle of the first shaft (2.1) does not cause rotation of the second shaft (3.2), can be applied to any of the embodiments of the invention.
The use of a return spring (7) biasing the exhaust valve (3) to remain open can be applied to any of the embodiments of the invention.
Figure 16 shows the graph of a function β=g(α) establishing the throttle requirements β of the exhaust valve (3) according to the opening degree α of the EGR valve (2). This correspondence can be experimentally established such that for a discrete set of values of the opening angle α of the EGR valve (2) it is determined which throttle value β of the exhaust valve (3) is optimal.
This graph shows an initial segment in which the function g is null. This segment is what corresponds to small opening values of the EGR valve (2). From a given pre-established value α₀, a larger opening of the EGR valve (2) gives rise to a higher throttle degree of the exhaust valve (3). This curve is what the mechanical linkage (5, 6) must reproduce. The kinematic chain formed by the drive component (5.1, 6.1), the drag component (5.3, 6.3), connected by the bar element (5.5, 6.5) by means of the first rotational attachment (5.2, 6.2) and the second rotational attachment (5.4, 6.4) establish a ratio β=f(α) in which f(α) must be as close as possible to g(α).
According to examples of the invention, the first null initial segment of g(α) is obtained by making use of a groove (6.6) which delays the action of the bar element (5.5, 6.5) on the drag component (5.3, 6.2). According to the first embodiment, this segment is obtained by means of a first circular arc segment in the configuration of the cam profile (5.1.1).
The curve of g(α) can be reproduced by f(α), adapting the cam profile to the movement that must be applied to the first rotational attachment (5.2) in order to give target angle β defined by g(α).
In the case of the second to the fifth embodiments, the curve of g(α) is approximated by the ratio of angles which determines the articulated quadrilateral formed by the crank (6.1), the bar element (6.5) and the drag component (6.3), respectively, once the movement established by the groove (6.6), should there be one, has finished. The lengths of each of the three elements as well as the relative initial angles have been modified in the embodiments. The adjustment of these parameters can be carried out numerically by means of solving a multivariate optimization problem, using as a target function a pre-established rule of the difference between f(α) and g(α).
Another object of this invention is also the module consisting of

a heat exchanger (8) for cooling EGR gas;
a device (1) according to any of the described examples, where the first EGR valve (2) is located in the cooled gas outlet of the heat exchanger (8) and the second exhaust valve (3) is fixed to one side of the heat exchanger (8) to receive the exhaust gas without being cooled by the heat exchanger (8).

Another object of this invention is also an EGR system for an internal combustion engine comprising a module like the one above.

Claims

A device (1) for managing exhaust gas in an internal combustion engine, comprising:
- a first EGR valve (2), comprising a first shaft (2.1) with a first flap (2.2), wherein the rotation of the first flap (2.2) determines the throttle degree of the passage through said first EGR valve (2); and wherein the first shaft (2.1) can be operated by drive means (4);

- a second exhaust valve (3), comprising a second shaft (3.1) with a second flap (3.2), wherein the rotation of the second flap (3.2) determines the throttle degree of the passage of said second exhaust valve (3); and wherein the second shaft (3.1) can be operated by the first shaft (2.1) by means of a mechanical linkage (5, 6) such that the opening of the first EGR valve (2) establishes the partial closure of the second exhaust valve (3);
wherein the first shaft (2.1) of the first EGR valve (2) and the second shaft (3.1) of the second exhaust valve (3) are parallel; and wherein the mechanical linkage (5, 6) between the first shaft (2.1) and the second shaft (3.1) comprises:
- a drive component (5.1, 6.1) that can be operated by the first shaft (2.1) comprising a first rotational attachment (5.2, 6.2), wherein the drive component (5.1, 6.1) establishes the movement of said first rotational attachment (5.2, 6.2);

- a drag component (5.3, 6.3) integral with the second shaft (3.1) comprising a second rotational attachment (5.4, 6.4) for operation;

- a bar element (5.5, 6.5) joining the first rotational attachment (5.2, 6.2) and the second rotational attachment (5.4, 6.4).
The device (1) according to claim 1, wherein the drive component (5.1) comprises:
- a cam (5.1.1) integral with the first shaft (2.1),

- a guide (5.1.3) housing a guided support element (5.1.4), wherein this guided support element (5.1.4) in turn comprises a cam follower (5.1.2), and where the cam follower (5.1.2) is driven and guided by the cam (5.1.1) determining the position of the guided support element (5.1.4) according to the angular position of the first shaft (2.1).
The device (1) according to claim 2, wherein the guided support element (5.1.4) has linear movement with respect to the guide (5.1.3) in which it is housed for the transmission of a linear motion to the first rotational attachment (5.2).
The device (1) according to claim 1, wherein the drive component (6.1) is a crank for the transmission of a circular motion to the first rotational attachment (6.2).
The device (1) according to any of the preceding claims, wherein the drag component (5.3, 6.3) is:
- either a crank with the second rotational attachment (5.4, 6.4) at one end,

- or a disc with the second rotational attachment (5.4, 6.4) spaced from the center of rotation established by the second shaft (3.1).
The device (1) according to any of the preceding claims, wherein the bar element (5.5, 6.5) comprises a groove (6.6) where either the first rotational attachment (5.2, 6.2) or the second rotational attachment (5.4, 6.4) is housed to determine the start of closure of the second exhaust valve (3) from a given rotation threshold value of the first flap (2.2).
The device according to any of the preceding claims, wherein the second exhaust valve (3) comprises a return spring (7) configured so that the second flap (3.2) is biased to be open.
The device according to any of the preceding claims, wherein the threshold value of the rotation angle of the first flap (2.2) before rotation of the second flap (3.2) starts for throttling the second exhaust valve (3) is comprised between 25% and 50% of the possible rotation angle.
The device according to claim 8, wherein the threshold value of the rotation angle of the first flap (2.2) before rotation of the second flap (3.2) starts for throttling the second exhaust valve (3) is comprised between 30% and 40% of the rotation angle possible.
A module comprising:
- a heat exchanger (8) for cooling EGR gas;

- a device (1) according to any of the preceding claims, wherein the first EGR valve (2) is located at the cooled gas outlet of the heat exchanger (8) and the second exhaust valve (3) is fixed to one side of the heat exchanger (8) to receive the exhaust gas without being cooled by the heat exchanger (8).
An EGR system for an internal combustion engine comprising a module according to the preceding claim.