JP2011185140A - Exhaust gas recirculation device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device capable of preventing variations in EGR gas concentration inside an intake flow passage and achieving a uniform EGR gas concentration distribution. <P>SOLUTION: A partition plate 2 is so shaped that, on a cross-sectional shape perpendicular to the central axis of a main cylinder unit 11 forming an intake flow passage, an imaginary straight line connecting both ends is located closer to a branch cylinder unit 12 forming an exhaust gas recirculation passage than to the central axis, and that its center portion expands past the imaginary straight line toward a side containing the central axis. The main flow of EGR gas can therefore be guided near the center portion of the partition plate 2, and intake flow in the center area of the main cylinder unit 11 where the flow speed of the intake flow is high is collided with the EGR gas to promote the mixing of the intake flow with the EGR gas so as to achieve a uniform EGR gas concentration distribution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine having an exhaust gas recirculation passage for recirculating a part of the exhaust gas of the internal combustion engine from an exhaust passage to an intake passage.

  Conventionally, the exhaust gas recirculation gas (EGR gas), which is part of the exhaust gas flowing in the exhaust passage of the internal combustion engine, is mixed in the intake air flowing in the intake passage, so that the oxygen concentration in the internal combustion engine is reduced. There has been known an exhaust gas recirculation device that uses a lower state in air and lowers the maximum combustion temperature to reduce harmful substances (for example, nitrogen oxides) contained in the exhaust gas.

  However, in the conventional configuration (conventional example 1), as shown in FIG. 5, the relationship between the cross-sectional areas of the exhaust gas recirculation path 33 and the intake flow path 31, that is, the fluids (EGR gas) flowing in the flow paths 31 and 33. ), The EGR gas high concentration portion (region where the concentration of EGR gas exceeds a certain threshold value) 51 is unevenly distributed on the upper side of the intake flow path 31 in the figure. In this way, when the EGR gas high concentration part is biased, in order to realize an optimal combustion state corresponding to the rotation range and load of the internal combustion engine, a large number of spark plugs are used or the ignition timing is controlled. This increases the size of the internal combustion engine unit and the complexity of the control system, and increases the cost.

  In order to solve this problem, in Patent Document 1, as shown in FIG. 6, a partition plate 62 is provided in the intake passage 31, and the exhaust gas recirculation is provided in one of the intake passages 31 partitioned by the partition plate 62. There has been proposed an exhaust gas recirculation device (conventional example 2) having a mixing channel connected to a channel 33. In this configuration, it is possible to prevent the EGR gas high concentration portion 51 as in the conventional example 1 from being unevenly distributed on one side of the intake flow path 31, but the EGR gas high concentration portion 51 is unevenly distributed in the direction along the partition plate 62. Resulting in. In addition, since the connection portion of the partition plate 62 and the intake passage 31 are in contact with each other as a whole, the partition plate 62 is cooled by contact heat conduction from the intake passage 31 whose temperature is kept low by the intake air. The hot EGR gas spreading along the plate 62 is rapidly cooled, and condensed water may be generated.

Japanese Utility Model Publication No. 2-122155

  An object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can prevent a deviation of EGR gas concentration in an intake flow path and realize a uniform EGR gas concentration distribution.

(Invention of Claim 1)
The present invention relates to an exhaust gas recirculation device for an internal combustion engine having an exhaust gas recirculation path for recirculating a part of the exhaust gas of the internal combustion engine from the exhaust flow path to the intake flow path. A partition plate that divides a part of the intake flow channel upstream of the manifold into two along the central axis direction of the intake flow channel is formed, and the exhaust gas is exhausted to one of the intake flow channels divided into two by the partition plate. A gas recirculation path is connected, and the partition plate has a cross-sectional shape perpendicular to the central axis of the intake flow path, a virtual straight line connecting both ends is on the exhaust gas recirculation path side from the central axis, and the central part is centered from the virtual straight line It is characterized by bulging to the side including the shaft.

  According to the above configuration, the main flow of EGR gas can be guided to the vicinity of the central portion of the partition plate, and the intake flow in the central region of the intake flow path where the flow velocity of the intake flow is high and the EGR gas high concentration portion collide with each other. Mixing of the intake air flow and the EGR gas can be promoted, and a uniform EGR gas concentration distribution can be realized.

(Invention of Claim 2)
2. The exhaust gas recirculation device for an internal combustion engine according to claim 1, wherein the partition plate is formed with chamfers for reducing a pressure loss of the intake air flow at an upstream end and a downstream end in a flow direction of the intake air flow. .

  According to the above configuration, since the partition plate is chamfered at the upstream end and the downstream end in the flow direction of the intake flow, the turbulent flow disturbs the flow of the intake flow at the upstream end and the downstream end of the partition plate. The pressure loss of the intake air flow can be reduced by suppressing the occurrence of the air flow and smoothing the flow of the intake air flow.

(Invention of Claim 3)
The exhaust gas recirculation device for an internal combustion engine according to claim 1 or 2, wherein the partition plate is provided with a notch at a connection portion with the intake passage.

  According to the above configuration, since the partition plate is provided with a notch in the connection portion with the intake flow path, the partition plate is in thermal contact with the intake flow path whose temperature is kept low by the low temperature intake flow. Can be reduced. As a result, heat conduction from the low-temperature intake flow path to the partition plate can be minimized, the temperature of the partition plate is prevented from lowering, and the high-temperature EGR gas contacting the partition plate is cooled and condensed. The generation of water can be prevented.

(Invention of Claim 4)
The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 3, wherein the partition plate has a V-shaped cross section perpendicular to the central axis of the intake flow path, and has both end portions and a central portion. It is characterized in that the angle formed by two connecting straight lines is 90 to 150 degrees.

  When the cross-sectional shape perpendicular to the central axis of the intake passage is V-shaped, if a partition plate having an angle formed by a straight line connecting both ends and the center is less than 90 degrees, The spread will not be sufficient. If a partition plate formed by a straight line connecting both end portions and the central portion is larger than 150 degrees, the configuration of Conventional Example 2 is approached, and the EGR gas high concentration portion is unevenly distributed along the partition plate. End up. Using a partition plate with two straight lines connecting the two ends and the center of the partition plate with an angle of 90 ° to 150 ° produces a concentrically uniform EGR gas concentration distribution around the central axis of the intake channel. Can be realized.

(Invention of Claim 5)
The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 4, wherein the partition plate is formed integrally with the intake passage.

  According to the above configuration, the partition plate is formed integrally with a part of the intake flow path, and further, a part of the intake flow path and a part of the exhaust gas recirculation path are formed integrally ( In the case where this portion is hereinafter referred to as a mixing channel with a partition plate), the number of parts does not increase significantly, and the assembling property can be made comparable to the conventional one.

1 is a schematic configuration diagram of an exhaust gas recirculation device according to Embodiment 1. FIG. It is a perspective view of the mixing flow path with a partition plate concerning Example 1. FIG. It is the principal part front view (a) of the mixing flow path with a partition plate concerning Example 1, and a top view (b). FIG. 3 is a half cross-sectional perspective view of a mixing channel with a partition plate according to Example 1; 10 is a half cross-sectional perspective view of a mixing channel according to Conventional Example 1. FIG. It is a half cross-sectional perspective view of the mixing flow path with a partition plate concerning the prior art example 2. FIG.

  A mode for carrying out the invention will be described together with embodiments shown in the drawings.

  FIG. 1 is a schematic configuration diagram of an exhaust gas recirculation device using a separate type mixed passage 1 with a partition plate according to Embodiment 1 of the present invention. The exhaust gas recirculation device according to the first embodiment is connected to an exhaust passage 32 formed in the exhaust pipe of the internal combustion engine 38, and an intake air flow in which a part of the exhaust gas is formed in the intake pipe via the three-way valve 40. An exhaust gas recirculation path 33 for recirculation (recirculation) to the path 31, and a partition plate 2 formed integrally with a part of the intake flow path 31 (referred to as a main cylinder portion 11 (described later)), A mixing channel 1 with a partition plate in which a branch cylinder portion 12 (described later) which is a part of the exhaust gas recirculation path 33 is connected to one of the main cylinder portions 11 divided into two by the partition plate 2. I have.

  On the upstream side of the intake flow of the main cylinder portion 11 in the mixing flow path 1 with a partition plate, an intake control valve 36 that adjusts the intake air amount passing through the intake flow path 31 at an average temperature of about 15 ° C. continuously or stepwise. It connects with the intake flow path 31 which has. Further, the downstream side of the main cylinder portion 11 is connected to an intake passage 31 connected to the intake manifold 37 of the internal combustion engine 38. Further, the branch cylinder portion 12 of the mixing channel 1 with the partition plate is connected to the exhaust gas recirculation path 33, and the EGR gas flowing through the connection portion of the exhaust gas recirculation path 33 is cooled by the EGR cooler 34 and 100. The EGR gas recirculation amount is controlled by the EGR control valve 35 continuously or stepwise. Here, the exhaust gas flow upstream end of the exhaust gas recirculation path 33 is connected to the exhaust manifold 39 of the internal combustion engine 38 via the three-way valve 40 and the exhaust flow path 32.

  FIG. 2 shows a mixing flow path 1 with a partition plate according to Embodiment 1 of the present invention. A main cylinder portion 11 forming an intake flow path 31 and an exhaust gas recirculation path 33 connected orthogonally to the main cylinder section 11 are shown. It is composed of a branch cylinder portion 12 to be formed and a partition plate 2 disposed in the main cylinder portion 11 in the flow direction of the intake air flow.

  FIG. 3: is the principal part front view (a) and top view (b) of the mixing flow path 1 with a partition plate concerning Example 1 of this invention. The partition plate 2 is formed integrally with the main cylinder part 11 along the central axis direction of the main cylinder part 11, and divides the main cylinder part 11 into two sections. A branch cylinder portion 12 is connected to one of the main cylinder portions 11 partitioned by the partition plate 2, and the partition plate 2 is an imaginary straight line connecting both ends in a cross-sectional shape perpendicular to the central axis of the main cylinder portion 11. Is on the side of the branch cylinder part 12 from the central axis, and the center part is an inverted V-shaped bulging to the side facing the branch cylinder part 12, and is closer to the branch cylinder part 12 side than the central axis of the main cylinder part 11. Has been placed.

The partition plate 2 is formed so that the thickness of the partition plate 2 decreases toward the upstream (left side in the drawing) end and the downstream (right side in the drawing) end in the flow direction of the intake flow so as to decrease the pressure loss of the intake flow. Has been chamfered. Moreover, in order to reduce the contact part with the main cylinder part 11, the partition plate 2 is provided with the notch part 21 in four places of the upstream end and downstream end of the flow direction of an intake flow.
Here, the mixing channel 1 with a partition plate is an integrally molded product made of resin such as PPS, for example, but any material can be used as long as desired heat resistance is obtained.

  Next, based on FIG. 4, the effect of the mixing flow path 1 with a partition plate concerning Example 1 of this invention is demonstrated. The partition plate 2 has a reverse V-shape in which the cross-sectional shape perpendicular to the central axis of the main cylinder portion 11 bulges to the side facing the branch cylinder portion 12 at the center portion, and the center of the main cylinder portion 11 It is the shape arrange | positioned at the branch cylinder part 12 side from the axis | shaft. For this reason, the main flow of EGR gas can be guided to the vicinity of the central portion of the partition plate 2, and the mixing of the intake air and the EGR gas is promoted by colliding the EGR gas with the central region where the flow velocity of the intake air is high. A concentric and uniform EGR gas concentration distribution can be realized with the central axis of the flow path 31 as the center. For this reason, the EGR gas high concentration portion 51 has a circular shape with the central axis of the intake passage 31 as the center.

  Further, the partition plate 2 is formed with a chamfer that reduces the thickness of the partition plate 2 toward the upstream end and the downstream end in the flow direction of the intake flow, thereby reducing the pressure loss of the intake flow. And a smooth intake flow can be achieved. Further, since the notch 21 is provided in the connecting portion between the partition plate 2 and the main tube portion 11, the partition is separated from the main tube portion 11 (about 15 ° C. equivalent to the intake air temperature) where the temperature is kept low. The heat conduction to the plate 2 can be minimized, the temperature can be prevented from being lowered, and the high temperature (about 100 ° C.) EGR gas in contact with the partition plate 2 can be prevented from being cooled to generate condensed water. .

  The present invention can be modified in various ways without departing from the gist thereof. For example, in the embodiment, the end portion of the partition plate 2 is a sharp type, but it may be formed in a cross-sectional wing shape in order to reduce the pressure loss. Moreover, the mixing channel with partition plate 1 may be made of resin or metal, and in that case, the shape may be realized by cutting or by casting. In the embodiment, the connection portions are provided at both ends of the intake flow path 31 and the partition plate 2, but the connection portions may be provided on only one side.

  Moreover, the mixing flow path 1 with a partition plate of this invention is not limited to the mixing flow path of the intake air and recirculation exhaust gas of an exhaust gas recirculation system, It can apply to arbitrary uses.

1 Mixing flow path with partition plate 11 Main cylinder (intake flow path)
12 Branch cylinder (exhaust gas recirculation path)
2 Partition plate 31 Intake passage 33 Exhaust gas recirculation passage 51 EGR gas high concentration part

Claims (5)

An exhaust gas recirculation device for an internal combustion engine having an exhaust gas recirculation passage for recirculating a part of the exhaust gas of the internal combustion engine from the exhaust passage to the intake passage,
The intake channel is formed with a partition plate that divides a part of the intake channel upstream of the intake manifold into two along the central axis direction of the intake channel,
The exhaust gas recirculation path is connected to one of the intake flow paths divided into two by the partition plate,
In the cross-sectional shape perpendicular to the central axis of the intake flow path, the partition plate has a virtual straight line connecting both end portions on the exhaust gas recirculation path side from the central axis, and a central portion includes the central axis from the virtual straight line An exhaust gas recirculation device for an internal combustion engine, characterized by bulging to the side. The exhaust gas recirculation device for an internal combustion engine according to claim 1,
An exhaust gas recirculation device for an internal combustion engine, wherein the partition plate is formed with chamfers for reducing a pressure loss of the intake air flow at an upstream end and a downstream end in a flow direction of the intake air flow. The exhaust gas recirculation device for an internal combustion engine according to claim 1 or 2,
The exhaust gas recirculation device for an internal combustion engine, wherein the partition plate is provided with a notch at a connection portion with the intake passage. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 3,
The partition plate has a V-shaped cross section perpendicular to the central axis of the intake flow path, and an angle formed by two straight lines connecting the both end portions and the central portion is 90 degrees to 150 degrees. An exhaust gas recirculation device for an internal combustion engine, which is provided in the engine. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 4,
The exhaust gas recirculation device for an internal combustion engine, wherein the partition plate is formed integrally with the intake passage.

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