EP3093478A1 - Combination valve with low pressure exhaust gas recirculation valve and intake air throttle for a combustion engine - Google Patents

Abstract

The invention relates to a combination valve with low-pressure exhaust gas recirculation valve and intake throttle for an internal combustion engine, with an exhaust inlet, an intake air inlet and an outlet, wherein between the exhaust inlet and the outlet, the low-pressure exhaust gas recirculation valve and between the intake air inlet and the outlet, the intake air throttle are arranged. The invention is characterized in that the combination valve has a kinematic element which actuates together the low-pressure exhaust gas recirculation valve and the intake air throttle, wherein a first return spring and a second return spring are provided, which independently exert a restoring force on the Ki nematikelement.

Description

Technical area

The present invention relates to a combination valve with low-pressure exhaust gas recirculation valve and intake air throttle for an internal combustion engine.

State of the art

In order to reduce the NO _x emissions of diesel engines and the CO ₂ emissions of gasoline engines, it is a goal to lower the combustion temperature in the combustion chamber. For this purpose, the pure air supplied to the internal combustion engine exhaust gas is added. In the case of diesel engines, this leads to a lowering of the reaction rate and thus of the combustion temperature. In gasoline engines, charge cycle losses can be avoided and also NO _x emissions can be reduced. A distinction is made in the exhaust gas recirculation (EGR) between a high-pressure EGR and a low-pressure EGR. In the case of the high-pressure EGR, the removal of the exhaust gas takes place in front of the turbine of a turbocharger. The extracted exhaust gas is introduced downstream of the compressor and the intake air throttle. In the case of the low-pressure EGR, the exhaust gas to be taken off is taken off after the exhaust gas aftertreatment and admixed in front of a turbocharger.

The present invention is concerned with low pressure EGR. It is known in the art to structurally combine a low pressure EGR valve and an intake throttle so that both controls operate together. If a larger amount of EGR gas is required, the intake throttle is gradually closed. Reducing the effective cross section in the intake tract by closing the intake air throttle locally generates a partial negative pressure and thus allows a greater removal or supply of exhaust gas.

In the mechanical integration of low-pressure exhaust gas recirculation valve and intake air throttle as a combination valve various approaches are known in the art. For example, in the documents DE 10 2010 032 824 A1 . DE 10 2011 007 303 A1 and DE 10 2011 053 664 A1 proposed a low-pressure EGR adjustment valve, which transmits via a slotted guide its movement directly to an intake throttle valve. This arrangement requires little space. It turns out, however a long kinematic chain regarding the transmission of mechanical forces to the intake throttle valve via the low pressure EGR adjustment valve. As a consequence, the arrangement has comparatively much play or high frictional forces and is accordingly error-prone. Furthermore, in case of an error, one of the components affects the whole chain, there is no redundancy.

The present invention has for its object to mitigate or eliminate the disadvantages mentioned.

Disclosure of the invention

A combined valve according to the invention has a low-pressure exhaust gas recirculation valve and an intake air throttle for an internal combustion engine. The combination valve comprises an exhaust inlet, an intake air inlet and an outlet. Between the exhaust inlet and the outlet, the low-pressure exhaust gas recirculation valve is arranged. Between the suction inlet and the outlet, the intake air throttle is arranged.

According to the invention, it is provided that the combination valve has a kinematic element which actuates together the low-pressure exhaust gas recirculation valve and the intake air throttle. In this connection, it should be noted that the term combination valve does not necessarily require a common housing for the low-pressure exhaust gas recirculation valve and the intake air throttle. Both can also be accommodated in separate housing units as long as the kinematics element actuates the low-pressure exhaust gas recirculation valve and the intake air throttle by its movement.

Furthermore, the combination valve has a kinematic element which actuates together the low-pressure exhaust gas recirculation valve and the intake air throttle, wherein a first return spring and a second return spring are provided, which independently exert a restoring force on the kinematic element. The kinematics element can be formed in one piece or in several parts.

By means of the arrangement according to the invention, it is possible to move both the low-pressure exhaust-gas recirculation valve and the intake-air throttle by a single movement of the kinematic element. In this way, although only one actuator present, but there are the kinematic ways for actuating the low-pressure exhaust gas recirculation valve and the intake air throttle different and thus at least partially decoupled. Thus, for example, when a jamming of the intake air throttle, the low-pressure exhaust gas recirculation valve still partially movable.

The provision of two independent spring forces, which act on the kinematic element in two different kinematic ways, represents a safety feature due to the redundancy. Two independent return springs substantially increase the mechanical reliability of the combination valve. In the event of a failure such as a break or the slow loss of the spring force of one of the two return springs, the other return spring can at least partially take over the function of the defective return spring. Furthermore, it is possible in the design of the entire restoring force of the kinematics element to combine two different return spring characteristics and thus to achieve a more uniform spring force distribution over the entire range of motion of the kinematic element. Thus, the first return spring can be designed as a compression spring and the second return spring as a torsion spring. For example, the first return spring acting directly on the kinematic element can be designed as a spherical pressure spring and the second return spring can be provided as a cylindrical torsion spring in particular.

In addition, two independently acting return springs make it possible to significantly reduce the movement of the components involved. It substantially reduces the tolerance chain within the array. This allows a more accurate and wear-free power transmission.

In a preferred embodiment it can be provided that the first return spring is set up so that it acts directly on the kinematic element and the second return spring is set up so that it indirectly acts on the kinematic element via the intake air throttle or the low-pressure exhaust gas recirculation valve. This results in a clear kinematic separation of the independently operating return springs, so that in case of failure of one of the two return springs, the other can at least partially take over the reset function.

An advantageous embodiment of the invention provides that the first restoring spring exerts on the low-pressure exhaust gas recirculation valve a force directed into a closed position and the second return spring on the intake air throttle exerts a force directed into an open position.

Furthermore, an advantageous embodiment results from the fact that the kinematic element has a first cage and a second cage, wherein in the first cage a drive element, in particular a drive crank for moving the kinematic element and the low-pressure exhaust gas recirculation valve engages, as well as in the second cage an output element engages the movement of the intake throttle. As a result, the kinematic decoupling between the movement of the kinematic element and the low-pressure exhaust gas recirculation valve, on the one hand, and the movement of the intake air throttle, on the other hand, takes place via the output element engaging in the second cage. It can thus be ensured at a malfunction of the function of the intake air throttle by a corresponding design of the second cage at least partially functionality of the low-pressure exhaust gas recirculation valve. In one embodiment of the drive element as a crank, a rotational movement of the drive element is correspondingly converted into a particular linear displacement movement of the kinematic element, and in one embodiment of the output element as a crank a particular linear displacement movement of the kinematic element is converted into a rotational movement of the intake air throttle.

An inventive development of the invention provides that the first cage with the second cage includes an angle different from 180 ° or 0 °. In particular, an angle of 90 ° can be provided. It can also be provided that the plane of movement of the drive element with the plane of movement of the output element includes an angle different from 180 ° or 0 °. In particular, this angle can be 90 °. By an angled arrangement of the first and second cage, the axes of the moving parts are perpendicular to each other. There is a better distribution of the forces of kinematic element drive and intake air throttle drive, which are to be absorbed by a housing.

A preferred embodiment of the combination valve according to the invention provides that the bearing of the drive crank a rolling bearing and the bearing of the output crank has a sliding bearing.

Another advantageous development of the invention provides that the second cage has a first and a second section. The first section lies opposite the second section in the direction of movement of the kinematics element. During a movement of the kinematic element in the intended direction of movement, therefore, an idle stroke arises on leaving the first section and contacting the second section. In this case, the engaging in the second cage portion of the output element and the output crank is dimensioned according to the distance of the two sections and it presses no force the output element against one of the two sections. Thus, between the two sections that interact with the output element, there is a game that allows the idle stroke.

A development of the invention provides that in normal operation in a range of motion of the kinematics element, the output element is pressed against the resistance of the intake air throttle in the direction of the first section due to the force applied by the second return spring restoring force in the direction of the first section and contacted. The first section of the second cage is thus the flank, which acts on the output element and controls the movement of the intake air throttle during normal operation. Under normal operation, it is understood here that the intake air throttle is substantially freely movable, that is, that the resistance to movement of the intake air throttle is less than the restoring force of the second return spring.

A likewise advantageous embodiment of the invention provides that in a movement region of the kinematics element with a corresponding movement of the kinematic element, the output element contacts the second section when the movement resistance of the intake air throttle exceeds the restoring force applied by the second return spring. This can be caused, for example, by jamming or icing of the intake air throttle. The intake throttle can not be moved solely by the return spring force. Now moves the kinematic element in a corresponding range of motion, the second section will come into contact with the output element. Due to the existing idle stroke between the first Section and the second section wins the kinematics element of kinetic energy and can transmit this impulse to the stuck intake throttle. In this way, a clamping or icy intake air throttle can be solved again. Alternatively or additionally, the distance between the first and the second section can be selected such that a limited operation of the low-pressure exhaust gas recirculation valve is possible even without contacting the second section with the output element.

Brief description of the drawings

Figur 1

eine perspektivische Teilansicht einer erfindungsgemäßen Ausführungsform eines Kombiventils;

Figur 2

eine perspektivische Ansicht eines Kinematikelements des in Figur 1 gezeigten Kombiventils;

Figur 3

eine weitere perspektivische Ansicht des Kinematikelements der Figur 2.

The invention will now be explained with reference to the accompanying drawings. Show it:

FIG. 1

a partial perspective view of an embodiment of a combination valve according to the invention;

FIG. 2

a perspective view of a kinematic element of in FIG. 1 shown combination valve;

FIG. 3

another perspective view of the kinematics of the FIG. 2 ,

Embodiment (s) of the invention

FIG. 1 shows a combination valve 10. In the illustration, parts of the housing and the air ducts have been omitted in order to better represent the functionality. The combination valve 10 has a low-pressure exhaust gas recirculation valve 11 and an intake air throttle 12.

The low-pressure Abgäsrückführuhgsventil 11 is disposed in an exhaust inlet 14. The exhaust gas inlet 14 may be connected, for example, to the exhaust tract downstream of the turbine of a turbocharger. For example, the low-pressure exhaust gas is removed in a diesel engine after the diesel particulate filter and preferably passed through a low-pressure exhaust gas recirculation cooler to reduce the exhaust gas temperature. The low-pressure exhaust gas recirculation valve 11 is in the in FIG. 1 shown embodiment designed as a linearly movable poppet valve. In the position shown, the valve disk is located in the valve seat and thus closes off the exhaust gas inlet 14.

The intake air throttle 12 has an intake air throttle valve 121 disposed in an intake air passage having an intake air inlet 16, for example, in the intake air passage downstream of an air filter (not shown). Upon actuation of the intake air throttle 12, the angular position of the intake air throttle valve 121 changes within the intake air passage, thus reducing the effective cross-section within the intake air passage. This results in a partial pressure gradient from the intake air inlet to the outlet 18. This in turn increases the influx of exhaust gas via the exhaust gas inlet 14. In the outlet 18, the supplied exhaust gas strikes the intake air. This is usually followed by an EGR mixer. There, the supplied exhaust gas is mixed with the intake air.

FIG. 2 shows the kinematic element 100 with parts of intake air throttle 12 and low-pressure exhaust gas recirculation valve 11.

The kinematics element 100 has a main body 1001, which extends substantially along an axis Y as an elongated cuboid. At a front end of the elongated in the Y direction cuboid, a first cage 110 is attached. The inside of the first cage 110 has substantially the shape of a slot whose narrow sides are closed by circles and whose diameter correspond to the width of the slot. The longitudinal sides of the slot substantially parallel to each other. Perpendicular to the plane of extent of the first cage 110, the second cage 120 extends substantially along an axis X. The second cage 120 has a substantially cuboidal geometry in the interior. On the side facing away from the main body 1001 of the kinematic element 100 side of the cage 120, the geometry tapers. This is for example in FIG. 3 good to see.

The cages 110, 120 are arranged substantially at 90 ° to each other. This implies that the engaging in the cages 110, 120 cranks are also offset in its plane of movement by 90 °.

In the first cage 110 engages a drive pin 113 of a drive crank 112 a. The drive pin 113 is supported by means of a ball bearing. The diameter of the ball bearing drive journal 113 substantially corresponds to the width of the slot of the cage 110. The power crank 112 rotates about an axis X and is driven, for example, by a motor (not shown). During the rotation of the drive crank 112 about the axis X, the drive journal 113 describes a circular segment path. In this case, the drive pin 113 moves within the cage 110 between two end positions and thereby moves the kinematic element 100 linearly along the axis Y. Thereby, no or little play of the drive pin 113 in the direction of the axis Y is provided.

The intake throttle valve 121 is rotatably mounted about an axis Z and has a driven crank 122. An output pin 123 of the output crank 122 engages in the second cage 120 a. During the linear movement of the kinematic element 100, the second cage 120 sets the output crank 122 in rotation about the axis Z and thus moves the intake air throttle 12 or its intake air throttle valve 121. The output crank 122 is coupled to a torsion spring 124. The torsion spring 124 embodied here by way of example as a cylindrical torsion spring exerts a rotational force on the output crank 122 in such a way that the output pin 123 bears against the second cage 120. In the FIG. 2 a position is shown in which the output pin 123 rests against a first portion 1201 of the second cage 120. The first section 1201 is the section 1201 of the second cage 120 which is located along the axis Y in the direction of the first cage 110.

The low-pressure exhaust gas recirculation valve 11 has a valve rod 130, at whose end facing away from the kinematic element 100 end a valve plate 131 is provided. The valve rod 130 is slidably mounted within a sleeve 132. The sleeve 132 is fixedly arranged relative to the kinematic element 100 and serves as a guide for the valve rod 130. At the end of the valve rod 130, which faces the kinematic element 100, there is a stop for a compression spring 114. The compression spring 114 is concentric with the axis Y and arranged to the valve rod 130. The compression spring 114 is executed here by way of example as a spherical compression spring to allow a small space requirement and ease of manufacture. The compression spring 114 exerts a spring force on the valve rod 130 and thus also on the valve disk 131 along the axis Y in the direction of the kinematic element 100 and thus presses the valve disk 131 in the direction of a valve seat. Valve rod 130 and valve plate 131 thus follow a movement of the kinematic element 100 along the axis Y immediately.

In the FIG. 2 and 3 shown position of the kinematic element 100 corresponds to a wide opening of the low-pressure Abgasrückführungsveritils 11 and a relatively strong closed position of the intake air throttle 12th

Both the compression spring 114 and the torsion spring 124 act rectilinearly on the kinematic element 100 and exert a force that pushes it along the axis Y in the direction of the drive crank 112. The compression spring 114 is supported on the sleeve 132 from. The torsion spring 124 is supported on a housing section, not shown. Providing two independent spring forces acting on the kinematic element 100 in two different kinematic ways is a safety feature. Further, this arrangement allows a significant reduction in the range of motion and substantially reduces the tolerance chain within the array.

Upon movement of the kinematic element 100 along the axis Y in the direction of the drive crank 112, the output pin 123 follows the second cage 120 and abuts against the first portion 1201, since the torsion spring 124 exerts a corresponding force on the output crank 122. Consequently, the intake air throttle 12 moves in the direction of its open position. At the same time, the compression spring 114 pushes the valve rod 130 along the axis Y in the direction of the drive crank 112. The valve plate 131 of the low-pressure exhaust gas recirculation valve 11 thus moves in the direction of its closed position.

If due to certain circumstances, the intake air throttle 12 jammed - for example, by icing or high thermal load - lifts in such a described movement of the kinematic element 100 along the axis Y in the direction of the drive crank 112 of the output pin 123 of the first portion 1201 of the second cage 120th with continued movement of the kinematic element 100 from the second section 1202. This idle stroke makes it possible to accelerate the entire mass moved by the kinematic element 100, so that a certain momentum transfer takes place when the output pin 123 hits the second section 1202 of the second cage 120 and breakage from the icing or clamping position of the intake air throttle 12 can take place , It is thus possible to exert a considerable breakaway force on the intake throttle 12 via the drive crank 112.

Furthermore, it can be provided that, before the kinematics element 100 reaches its lower end point of the movement, the end position of the intake air throttle 12 is already reached. This can be achieved for example by a stop for a movable part of the intake air throttle 12. If the kinematics element 100 then continues its movement, the output pin 123 also lifts off from the first section 1201. The resulting idle stroke can be used to ensure that when opening the low-pressure exhaust gas recirculation valve 11 from its closed position initially the intake air throttle 12 remains in its open position. Only after completion of the idle stroke of the output pin 123 contacts the second cage 120 at its first portion 1201 and thus initiates the closing operation of the intake air throttle 12 a.

Claims (10)

Combination valve (10) with low-pressure exhaust gas recirculation valve (11) and intake air throttle (12) for an internal combustion engine, with an exhaust gas inlet (14), an intake air inlet (16) and an outlet (18), wherein between the exhaust gas inlet (14) and the outlet ( 18), the low-pressure exhaust gas recirculation valve (11) and between the intake air inlet (16) and the outlet (18), the intake air throttle (12) are arranged, wherein the combination valve (10) comprises a kinematic element (100), which together the low-pressure exhaust gas recirculation valve ( 11) and the intake air throttle (12) is actuated, wherein a first return spring and a second return spring are provided, which independently exert a restoring force on the kinematic element (100). Combination valve (10) according to claim 1, characterized in that the first return spring is arranged so that it acts directly on the kinematic element (100) and the second return spring is arranged so that it via the intake air throttle (12) or the low-pressure exhaust gas recirculation valve (11) acts indirectly on the kinematic element (100). Combination valve (10) according to claim 1 or 2, characterized in that the first return spring as a compression spring (114) and the second return spring as a torsion spring (124) are executed. Combination valve (10) according to one of the preceding claims, characterized in that the first return spring exerts on the low-pressure exhaust gas recirculation valve (11) a directed in a closed position and the second return spring on the intake air throttle (12) directed in an open position force. Combination valve (10) according to one of the preceding claims, characterized in that the kinematic element (100) has a first cage (110) and a second cage (120), wherein in the first cage (110) a drive element, in particular in the form of a drive crank (112) for moving the kinematic element (100) and the low-pressure exhaust gas recirculation valve (11) engages, as well as in the second cage (120) an output element, in particular in Form of a driven crank (122) for moving the intake air throttle (11) engages. Combination valve (10) according to claim 5, characterized in that the first cage (110) or a plane of movement of the drive element with the second cage (120) or with a plane of movement of the output element from 180 degrees or 0 degrees different angle, in particular an angle of 90 degrees, includes. Combination valve (10) according to one of claims 5 or 6, characterized in that the bearing of the drive crank (112) has a roller bearing and the bearing of the output element (122) has a slide bearing. Combination valve (10) according to one of claims 5 to 7, characterized in that the second cage (120) has a first portion (1201) and a second portion (1202), wherein the first portion (1201) and the second portion (1202 ) in the direction of movement of the kinematic element (100) are spaced from each other so that the output element between the first portion (1201) and the second portion (1202) has a game. Combination valve (10) according to claim 8, characterized in that in a movement range of the kinematic element (100) in a normal operation, which is characterized in that a restoring force of the second return spring exceeds a movement resistance of the intake air throttle (12), the output element by means of the restoring force of second return spring to the first portion (1201) is pressed contacting this. Combination valve (10) according to claim 9, characterized in that in the movement range of the kinematic element (100) in an icing or blocking state, which is characterized in that the resistance to movement of the intake air throttle (12) exceeds the restoring force of the second return spring, during a movement of the kinematic element (100) in a closing direction of the low-pressure exhaust gas recirculation valve (11), the output element contacts the second section (1202) and from which the movement resistance of the intake air throttle is overcome (12) by the kinematic element (100).

Images