EP3538753A1

EP3538753A1 - Control device for an internal combustion engine

Info

Publication number: EP3538753A1
Application number: EP17793661.4A
Authority: EP
Inventors: Thorsten REIMERS; Patrick SUTTY; Dirk VIERKOTTEN
Original assignee: Pierburg GmbH
Current assignee: Pierburg GmbH
Priority date: 2016-11-14
Filing date: 2017-11-03
Publication date: 2019-09-18
Anticipated expiration: 2037-11-03
Also published as: EP3538753B1; DE102016121705B4; DE102016121705A1; WO2018087004A1

Abstract

Control devices for internal combustion engines are known with an intake duct (12), an exhaust gas recirculation duct (16) which opens into the intake duct (12), a housing (10), in which the intake duct (12) and at least one opening (14) of the exhaust gas recirculation duct (16) are configured, a shaft (36) which serves as a rotational axis (38) and is arranged in the housing (10) upstream of the opening (14) of the exhaust gas recirculation duct (16) with regard to the air flow and outside the throughflow cross section of a first duct section (19) of the intake duct (12), a control body (42) which is fastened eccentrically to the shaft (36), a first duct section (19), at the downstream end of which a first valve seat (50) is configured, against which the control body (42) bears in a first end position, and a second valve seat (72) on the second duct section, against which second valve seat (72) the control body (42) bears in a second end position. Said control devices have the disadvantage, however, of an increased pressure loss as a result of undesired eddy formation. In order to solve said problem, it is proposed according to the invention that the shape of a surface (54) of the control body (42), which surface (54) points towards the interior of the intake duct (12), in the second end position corresponds in a cross section perpendicularly with respect to the centre axis (20) over an angle of at least 90° to an inner wall surface (56) of the first duct section (19), which inner wall surface (56) adjoins the control flap (42).

Description

DESCRIPTION

Regulating device for an internal combustion engine

The invention relates to a control device for an internal combustion engine having an intake passage, an exhaust gas recirculation passage, which opens into the intake passage, a housing in which the intake passage and at least one mouth of the exhaust gas recirculation passage are formed, serving as a rotation axis, the upstream in the housing with respect to the air flow the outlet of the exhaust gas recirculation passage and disposed outside the flow cross section and is arranged perpendicular to the center axes of the intake passage and the exhaust gas recirculation passage, a control body, which is eccentrically mounted on the shaft, a first channel portion, at the downstream end of which a first valve seat is formed, against the the control body rests in a first end position, and whose outer circumference is smaller than the outer circumference of a downstream adjoining second channel section and a second valve seat on the second channel section, on which the control body in a second end position is applied, in which the control body closes the exhaust gas recirculation passage.

Control devices are used in internal combustion engines to regulate exhaust or air quantities that are to be removed or supplied to combustion. Combinations of these control valves, in which two valve bodies are actuated via a common actuating device, are known. In particular, combinations of an exhaust gas recirculation valve with a throttle valve have been disclosed. In these embodiments, the exhaust gas recirculation channel opens immediately downstream of serving as a throttle valve in the air intake passage. When desired increase in the exhaust gas recirculation rate is then with opening the Exhaust gas recirculation valve to the same extent the throttle valve closed, which has an increase in the pressure gradient in the exhaust gas recirculation channel result, whereby the proportion of exhaust gas compared to the intake air quantity is increased. Such an arrangement is disclosed for example in DE 27 03 687 AI.

From DE 10 2014 114 968 AI a control device is also known, are operated in the two parallel flaps on a common eccentrically arranged rotary shaft, so that with rotation of the two flaps, the first flap from the valve seat of the air intake duct, while the second Flap approaches the valve seat of the exhaust gas recirculation channel until the air intake passage is fully opened and the exhaust gas recirculation passage is completely closed. Both for the second flap, which controls the exhaust gas recirculation channel, and for the first flap, which dominates the air intake channel, the valve seats are each designed as circumferential stops, against which the flaps rest circumferentially in their position closing the respective channel. The rotary shaft is disposed on a housing wall between the mouth of the exhaust gas recirculation passage and the valve seat in the air intake passage, but disposed outside the flow area of the upstream passage portion.

Although a sufficient controllability of the exhaust gas flow and the air flow is ensured by these known arrangements, there is an increased pressure loss in the flow through the intake passage both in the fully open position of the intake passage and in a throttling the intake passage position. Furthermore arise in an arrangement of the control device in front of a compressor problems with respect to a condensate formation when mixing the exhaust stream with the air flow, which leads to damage to the compressor. It is therefore an object of the invention to provide a control device for an internal combustion engine, with which the flow losses in the different positions of the control body are kept as low as possible in order to improve the filling of an internal combustion engine and the flow of a subsequent compressor can. In addition, the formation of condensate in the mixed gas stream downstream of the exhaust gas recirculation channel should be excluded as much as possible in order to prevent damage to a subsequent compressor.

This object is achieved by a control device for an internal combustion engine with the features of the main claim.

Characterized in that the shape of a pointing to the interior of the intake passage surface of the control body in the second end position in a cross section perpendicular to the central axis over an angle of at least 90 ° corresponds to a control flap adjacent inner wall surface of the first channel section, the first channel section via a peripheral portion in Substantially extended without interference, whereby vortices are prevented in the region of the exhaust gas inlet or on the outer sides of the control body, so that a significant reduction in pressure losses is achieved. At the same time, the mixture of the warm exhaust gas flow with the cold air flow is delayed by this flow guidance, whereby the amount of condensate is reduced, so that a subsequent compressor is protected from damage by liquid water.

The shape of the surface of the control body facing the interior of the intake duct preferably corresponds in the second end position in a cross section perpendicular to the central axis over half the circumference of the inner wall surface of the first duct section adjacent to the control flap. Dead spaces in which vortices can form are thus avoided, because of the otherwise necessary cross-sectional widening can be dispensed with for the flap freewheel. This means that the intake passage is extended in the region of the control body in the position releasing the intake passage of the control body as far as possible without interference, since the widening region of the housing, in which pivots the control body is separated by the control body from the perfused area, now a straight History has. Even in the positions in which a throttling of the intake channel takes place, a largely continuous transition between the first channel section and the channel section, in which the control body is rotated, is achieved, so that here the vortex formation and concomitant pressure losses are reduced, so that also the flow of a subsequent compressor is improved. The throttle effect is also enhanced.

In a further advantageous embodiment, the control body extends in the second end position to a third channel portion, the inner circumference is smaller than the inner circumference of the second channel portion, so that a steady course without cross-sectional jumps between the second and the third channel section in the intake passage releasing control body can be produced. Thus, the pressure loss can be kept low in this area.

In a preferred embodiment of the invention, the first valve seat is formed by an axial end of a first housing part of the housing, which forms the first channel section and projects into a second housing part of the housing, which forms at least the second channel section. In this way, the valve seat can be easily edited prior to assembly. In addition, a full-surface support of the control body on the first valve seat for closing the intake passage is easy to manufacture, since the first housing part projects into the second and thus provides an axial contact surface, which allows a tight seal. In a further embodiment, the first housing part is connected via a flange to the second housing part. This allows easy installation with high density at the same time between the housing parts.

Preferably, in its first end position, the regulating body lies completely circumferentially against the first valve seat at the end of the first housing part. This allows a tight closure of the intake passage through the axial abutment. As a result, a large closing force of the control body also acts on the valve seat, since the component acting in the axial direction of the force resulting from the applied torque is large. Thus, smaller actuators can be used.

In a preferred embodiment, the central axis of the first channel section is parallel to the central axis of the third channel section. Thus, a flow guide without shoulders and deflections can be made, whereby the flow resistance is kept low.

Furthermore, it is advantageous if a first plane spanned by the first valve seat is arranged at an angle of 75 ° to 80 ° to a second plane spanned by the second valve seat. As a result, the adjustment range, in which only small changes in volume flow of the two gas streams at relatively large existing angles kept low, which significantly improves the controllability.

In a further embodiment, the first plane includes an acute angle to a plane which is perpendicular to the central axis of the intake passage, and the second plane an acute angle to a plane which is perpendicular to the central axis the exhaust gas recirculation channel is arranged, a. Accordingly, the valve seat surfaces are inclined relative to each other to the channel center axes, whereby the adjustment paths are short and allow quick control.

Preferably, the control body has a first flap part on which the surface is formed, which rests in the first end position against the first valve seat and a second flap part, which rests in the second end position against the second valve seat, wherein the two flap parts via a Intermediate element are connected to the shaft. The second flap part consists for example of a tiltably received in a bore of the intermediate member holding axis and a flat flap body attached thereto. This simplifies the production of the control body.

Thus, a control device is provided with which both the air mass flow in the intake passage and the exhaust gas mass flow of the exhaust gas recirculation channel can be controlled quickly and precisely over a large adjustment angle range, whereby existing pressure losses are minimized by avoiding flow obstacles and dead spaces in which undesired eddies could form be reduced. Instead, a largely uniform flow without cross-sectional jumps is generated. Due to the reduced turbulence, the flow of a subsequent compressor is improved and prevents damage to the compressor by reducing the amounts of condensate incurred by better separation of the exhaust gas flow from the air flow.

An embodiment of a control device according to the invention is shown in the figures and will be described below. 1 shows a side view of a control device according to the invention with a control body in a first end position in a sectional view.

2 shows a side view of the control device according to the invention from Figure 1 with a control body in a second end position in a sectional view.

3 shows a top view of the control device according to the invention from Figure 2 with a control body in the second end position in a sectional view.

The control device according to the invention consists of a housing 10 which defines an intake passage 12 and in which an opening 14 of an exhaust gas recirculation passage 16 is formed. The intake passage 12 extends substantially in a straight line, while the exhaust gas recirculation passage 16 opens perpendicular to the intake passage 12 in this.

The housing 10 consists of a first, substantially tubular housing part 18, which forms a first channel portion 19 and whose downstream end is formed obliquely and an angle a of about 75 ° to a central axis 20 of the housing part 18 includes. The downstream end of the first housing part 18 is arranged in the interior of a second housing part 22, or is inserted into the second housing part 22 until a flange 24, via which the first housing part 18 is fastened by means of screws 26 on the second housing part 22. The second housing part 22 forms a second channel section 28, in which an opening 30 is formed, which is arranged in the flow direction at a short distance behind the oblique end of the first housing part 18 and which serves as a receptacle for a third housing part 32, which Mouth 14 of the exhaust gas recirculation passage 16 forms, the central axis 34 is arranged perpendicular to the central axis 20 of the intake passage 12.

In the housing 10, a shaft 36 is rotatably mounted, which can be actuated via a non-visible actuator. The axis of rotation 38 of this shaft 36 is perpendicular to the central axes 20, 34 and is located between the shaft 36 to the downstream mouth 14 of the exhaust gas recirculation passage 16 and the axial end of the first housing part 18 and immediately downstream of the first housing part 18. The total cross section of the first housing part 18 is smaller than that of the second housing part 22 of the intake passage 12, wherein the first housing part 18 is secured to the second housing part 22 such that a recess 40 formed in the region of the mouth 14 of the exhaust gas recirculation passage 16 is arranged outside the flow cross section, in which the shaft 36 the second housing part 22 is arranged penetrating.

At this eccentrically arranged in the intake passage 12 shaft 36, a control body 42 is fixed, which is rotatably disposed within the second channel portion 28 and consists of a first flap portion 44 and a second flap portion 45 having a holding axis 46 and a tiltably attached thereto flap body 48, wherein the support shaft 46 is mounted tiltably in a bore of an intermediate element 49. The intermediate element 49 is either made in one piece with or connected to the first flap part 44 and has a connection to the shaft 36. Upon rotation of the shaft 36 thus the first flap portion 44 is rotated in a first end position against the end of the first housing part 18, which serves as a first valve seat 50, while in rotation in the opposite direction of the valve body 48 in a second end position against one end of the mouth 14 of the exhaust gas recirculation passage 16 is rotated, which serves as a second valve seat 52. Accordingly, upon rotation of the shaft 36 to the extent in which the first flap portion 44 releases the intake passage 12, the exhaust gas recirculation passage 16 closed by the valve body 48 and vice versa. The tiltable attachment of the second flap portion 45 leads in this rotational movement of the shaft 36 in a second end position in which the flap body 48 rests on the second valve seat 52, to ensure that a complete tight closure of the exhaust gas recirculation passage 16, since the valve body 48 is in its position the possible tilting movement can be adapted to the position of the second valve seat 52, even if it is not completely aligned with the axis of rotation 38.

In the illustrated in Figure 2 second end position of the control body 42 of the valve body 48 rests on the valve seat 52 of the exhaust gas recirculation passage 16, while the first flap part 44, the intake passage 12 completely free. In this position, the first channel portion 19 is extended approximately over its half closer to the exhaust gas recirculation channel 16 facing circumference by a correspondingly shaped surface 54 of the control body 42, which is particularly visible in Figure 3. This means that in a cross section to the central axis 20 of the first housing part 18 in the region of the control body 42, the shape of the central axis 20 facing surface 54 of the control body 42 over a defined peripheral portion of the shape of an inner wall surface 56 of the first housing part 18, which on the control body 42nd borders, corresponds. This has the consequence that the inflowing air flow can flow as far as possible without flow obstacles from the first channel section 19 into the second channel section 28. Since the control body 42 also extends in this state as far as possible through the second channel section 28 to a third channel section 58, whose central axis 60 is parallel to the central axis 20 of the first housing part 18 and only slightly offset from it is arranged and its circumference compared to the second Channel section 28 is reduced again, also takes place here a largely undisturbed flow along the intake passage 12, so that occurring pressure losses are minimized.

If the control body 42 is rotated from its second end position into its first end position shown in FIG. 1, both exhaust gas and air can initially flow into the intake duct 12 since both flow cross-sections surrounding the valve seats 50, 52 are at least partially released. In contrast to known embodiments, however, the air flow is forwarded largely turbulence-free, since side wings 62 of the first flap portion 44, a flow around the first flap portion 44, which would lead to increased vortex formation, significantly reduced. Instead, a directional flow is produced, which also significantly reduces a sudden mixing of the cold air flow with the warm recirculated exhaust gas flow, so that condensation of the water vapor present in the exhaust gas flow is reduced. As a result, on the one hand, the load on a subsequent compressor is significantly reduced by condensed water and on the other hand, the flow of the compressor significantly improved because a directed flow can be selectively guided to the compressor, which in turn leads to increased efficiency of the compressor.

In order to ensure a tight seal on the first valve seat 50 at the end of the rotational movement in the first end position, this is adapted to the shape of the first flap portion 44 with respect to its shape, so that this flap portion 44, as shown in Figure 1, completely circumferential axially abuts against the first valve seat 50.

In order to achieve the best possible and fast control in the intermediate positions, a plane 64, which is spanned by the first valve seat 50, disposed at an angle of about 75 ° to a second plane 66, which spanned by the second valve seat 52 is, so that the total rotation angle of the shaft 36th or the control body 42 between the two end positions is relatively low, which over a significantly increased percentage rotation angle range, an approximately linear control of the air flow and the recirculated exhaust gas mass flow is achieved.

In addition, these planes 64, 66 each tilted to the shaft 36 in comparison to their central axes 20, 34, so that even over the circumference of the valve seat uniformly high closing force is generated.

The control device described is thus suitable for very accurate metering and directed, largely vortex-free guidance of an exhaust gas mass flow and an air mass flow to the engine. In this case, a subsequent compressor can be flowed directed, condensation of the water vapor in the exhaust stream and total pressure loss can be reduced by unwanted vortex formation and thus the performance of an internal combustion engine or a subsequent compressor can be improved. In addition, the second housing part can be made smaller, since the otherwise necessary for the flap free punch to drive them to the second end position is not required.

It should be understood that the scope of the present application is not limited to the embodiment described. In particular, the position of the valve seats and their tilt angle can be changed to the central axes or the position of the channels to each other can be changed. The shape of the flap body should each be adapted to the existing channel so that the surface may be round, oval or possibly square depending on the shape of the inner wall surface.

Claims

Pierburg GmbH, 41460 Neuss PATENT APPLICATIONS

1. Control device for an internal combustion engine with

an intake passage (12),

an exhaust gas recirculation passage (16) opening into the intake passage (12),

a housing (10) in which the intake passage (12) and at least one orifice (14) of the exhaust gas recirculation passage (16) are formed, a shaft (36) serving as an axis of rotation (38) in the housing (10) upstream of the air flow the mouth (14) of the exhaust gas recirculation passage (16) and outside the

Flow cross-section of a first channel portion (19) of the intake passage (12) is arranged,

a control body (42) which is mounted eccentrically on the shaft (36),

a first channel section (19), at the downstream end of which a first valve seat (50) is formed, against which the control body (42) abuts in a first end position and whose outer circumference is smaller than the outer circumference of a downstream second channel section (28) and

a second valve seat (72) on the second channel section, against which the control body (42) rests in a second end position, in which the control body (42) closes the exhaust gas return duct (16),

characterized in that

the shape of a surface (54) of the control body (42) facing the interior of the intake duct (12) in the second end position in a cross-section perpendicular to the central axis (20) over an angle of at least 90 ° of an inner wall surface adjacent to the control flap (42) ( 56) of the first channel section (19).

2. Control device for an internal combustion engine according to claim 1, characterized in that

the shape of the surface (54) of the control body (42) facing the interior of the intake duct (12) in the second end position in a cross section perpendicular to the central axis (20) over half the circumference of the inner wall surface (56) of the control flap (42) first channel portion (19) corresponds.

3. Control device for an internal combustion engine according to one of claims 1 or 2,

characterized in that

the control body (42) extends in the second end position to a third channel portion (58) whose inner circumference is smaller than the inner circumference of the second channel portion (28).

4. Control device for an internal combustion engine according to one of the preceding claims,

characterized in that

the first valve seat (50) is formed by an axial end of a first housing part (18) of the housing (10) which forms the first channel section (19) and protrudes into a second housing part (22) of the housing (10) second channel section (28) forms.

5. Control device for an internal combustion engine according to claim 4,

characterized in that

the first housing part (18) is connected to the second housing part (22) via a flange (24).

6. Control device for an internal combustion engine according to one of the preceding claims,

characterized in that the control body (42) rests in its first end position completely circumferentially against the first valve seat (50) at the end of the first housing part (18).

7. Control device for an internal combustion engine according to one of claims 3 to 6,

characterized in that

the central axis (20) of the first channel section (19) runs parallel to the central axis (60) of the third channel section (58).

8. Control device for an internal combustion engine according to one of the preceding claims,

characterized in that

a first plane (64) spanned by the first valve seat (50) is arranged at an angle of 75 ° to 80 ° to a second plane (66) spanned by the second valve seat (52).

9. Regulating device for an internal combustion engine according to claim 8,

characterized in that

the first plane (64) subtends an acute angle to a plane which is perpendicular to the central axis (20) of the intake duct (12) and the second plane (66) makes an acute angle to a plane perpendicular to the central axis (34) the exhaust gas recirculation passage (16) is arranged includes.

Control device for an internal combustion engine according to one of the preceding claims,

characterized in that

the regulating body (42) has a first flap part (44), on which the surface (54) is formed, which in the first end position abuts against the first valve seat (50) and has a second flap part (45), which in the second End position against the second valve seat (52) is applied, wherein the two flap parts (44, 45) via an intermediate element (49) are connected to the shaft (36).