JP2017040224A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine that can improve packaging performance compared to conventional cases and enables more compact packaging.SOLUTION: An exhaust emission control device 1 for an internal combustion engine includes a differential pressure sensor 14. The differential pressure sensor includes: a differential pressure sensor body section 140 provided in the vicinity of an outer portion upstream of an EGR passage 11; a first pressure detection section 141 provided upstream of the EGR passage 11 and connected to the differential pressure sensor body section 140; a differential pressure detection passage 143 formed in a housing 13 and connected to the downstream side of the EGR passage 11 via a connection passage 144; and a second pressure detection section 142 provided on the side opposite to the connection passage 144 of the differential pressure detection passage 143 and connected to the differential pressure sensor body section 140.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an exhaust emission control device for an internal combustion engine.

  2. Description of the Related Art Conventionally, EGR technology is known that recirculates part of exhaust gas flowing through an exhaust passage of an internal combustion engine to an intake passage of the internal combustion engine. According to this EGR technique, it is said that the combustion temperature in the cylinder can be lowered by mixing exhaust with fresh air, and NOx in the exhaust discharged from the internal combustion engine can be reduced.

  In the EGR technique, an EGR passage for returning a part of the exhaust gas flowing through the exhaust passage to the intake passage and an EGR valve for controlling the flow rate of the returned exhaust gas are provided. In order to control the EGR valve, a differential pressure sensor that detects a pressure difference between the upstream side and the downstream side of the EGR valve is provided (see, for example, Patent Document 1).

JP 2010-084519 A

  However, conventionally, as shown in FIG. 6, differential pressure detection passages 141 </ b> B and 142 </ b> B that connect the pressure detection units 141 </ b> A and 142 </ b> A on the upstream side and the downstream side of the EGR valve 12 and the differential pressure sensor main body part 140 </ b> A, It is provided separately from the EGR passage 11. For this reason, it is necessary to provide a differential pressure detection passage and wiring parts outside the EGR passage 11, and there is a problem that the packaging property is poor in view of securing clearance with peripheral parts.

  Further, conventionally, in order to prevent the blow bioy pool, the condensed water pool and the freezing associated therewith, the differential pressure detection passages 141B and 142B are connected to the upper portion of the EGR passage 11, and the differential pressure detection passage 142B is run up. It was necessary to use an inclined structure. Therefore, the mounting position of the differential pressure sensor main body 140A has to be high, and there is a problem that compact packaging is difficult.

  The present invention has been made in view of the above, and an object of the present invention is to provide an exhaust emission control device for an internal combustion engine that can improve the packaging performance as compared with the prior art and can be more compactly packaged.

  (1) In order to achieve the above object, the present invention is an exhaust purification device (for example, an exhaust purification device 1 described later) that is provided in an exhaust system of an internal combustion engine and purifies exhaust gas of the internal combustion engine, and includes the internal combustion engine. A part of the exhaust gas flowing through the exhaust passage is provided in an EGR passage (for example, an EGR passage 11 described later) that recirculates to the intake passage of the internal combustion engine, and is returned to the intake passage from the exhaust passage. An EGR valve (for example, an EGR valve 12 described later) for controlling the flow rate of exhaust gas, a housing (for example, a housing 13 described later) in which the EGR passage is formed and stores the EGR valve, and the EGR A differential pressure sensor (for example, a differential pressure sensor 14 to be described later) for detecting a pressure difference between the upstream side and the downstream side of the EGR valve in the passage, the differential pressure sensor of the EGR valve When one of the flow side and the downstream side is set to one side and the other is set to the other side, a differential pressure sensor main body (for example, a differential pressure sensor main body described later) provided near the outside of the one side of the EGR passage. Part 140), a first pressure detection part (for example, a first pressure detection part 141 described later) provided on the one side of the EGR passage and connected to the differential pressure sensor main body part, and formed in the housing And a differential pressure detection passage (for example, a differential pressure detection passage 143 to be described later) connected to the other side of the EGR passage via a connection passage (for example, a connection passage 144 to be described later), and the differential pressure Exhaust gas purification of an internal combustion engine provided with a second pressure detector (for example, a second pressure detector 142 described later) provided on the opposite side of the connection passage in the detection passage and connected to the differential pressure sensor main body Device.

In the invention of (1), the differential pressure detection passage is provided inside the housing, and the first pressure detection unit and the second pressure detection unit are integrated on either the upstream side or the downstream side of the EGR valve. This eliminates the need to provide a differential pressure detection path and wiring components outside the EGR path, thereby improving the packaging of the apparatus.
Further, since the differential pressure detection passage is provided inside the housing, the mounting position of the differential pressure sensor main body can be made lower than in the prior art. Therefore, according to the invention of (1), more compact packaging is possible.

  (2) It is preferable that the said differential pressure detection channel | path inclines below as it goes to the said connection channel | path side from the said 2nd pressure detection part side.

  In the invention of (2), the differential pressure detection passage is provided so as to incline downward from the second pressure detection portion side toward the connection passage side. As a result, it is possible to prevent the blow bioile pool and condensate pool in the differential pressure detection passage and the freezing associated therewith. The differential pressure can be accurately detected and highly accurate EGR valve control can be performed, and the packaging of the device is improved. it can.

  (3) It is preferable that the connection passage is inclined downward from the differential pressure detection passage side toward the EGR passage side in the housing.

  In the invention of (3), the connection passage connecting the EGR passage and the differential pressure detection passage is formed in the housing so as to be inclined downward from the differential pressure detection passage side toward the EGR passage side. As a result, the blow buoy pool, condensed water pool and freezing associated therewith in the connection path connecting the EGR path and the differential pressure detection path can be prevented, and the above-described effects can be exhibited more remarkably.

  (4) A lowermost end portion of the connection passage (for example, a lowermost end portion 145 of a connection passage 144 described later) is a central axis of the EGR passage to which the connection passage is connected (for example, a central axis of the EGR passage 11 described later). It is preferable that it is located in the lowest end part in the position of the X) direction.

  In the invention of (4), the lowermost end portion of the connection passage is disposed at the lowermost end portion in the axial position of the EGR passage to which the connection passage is connected. As a result, the position of the connecting passage connecting the differential pressure detecting passage and the EGR passage can be arranged at the lowest position, so that the mounting position of the differential pressure sensor main body can be further lowered, and further compact packaging becomes possible.

  According to the present invention, it is possible to provide an exhaust emission control device for an internal combustion engine that can improve the packaging performance as compared with the related art and can be more compactly packaged.

1 is a perspective view of an exhaust emission control device for an internal combustion engine according to an embodiment of the present invention. It is a permeation | transmission perspective view of the exhaust gas purification apparatus of the internal combustion engine which concerns on the said embodiment. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a schematic diagram of the exhaust gas purification apparatus for an internal combustion engine according to the embodiment. It is a schematic diagram of the exhaust emission control device of the conventional internal combustion engine.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a partially transparent perspective view of the exhaust emission control device 1 according to the present embodiment. 3 is a cross-sectional view taken along line AA in FIG. 4 is a cross-sectional view taken along line BB in FIG. As shown in FIGS. 1 and 2, an exhaust purification device 1 of an internal combustion engine (hereinafter referred to as “engine”) according to the present embodiment includes an EGR device 10.

  The engine of this embodiment (not shown) is an inline 4-cylinder diesel engine. In either case, intake air is supplied to a combustion chamber of each cylinder (not shown) via an intake pipe, and fuel is directly injected by a fuel injection valve provided in each cylinder. Exhaust gas generated by the combustion is discharged through an exhaust pipe.

  Further, the engine of this embodiment includes a supercharger that pumps intake air into the intake pipe. The supercharger includes a turbine provided in the exhaust pipe and a compressor provided in the intake pipe. The turbine is driven by the kinetic energy of the exhaust flowing through the exhaust pipe. The compressor is rotationally driven by the turbine, pressurizes the intake air, and pumps it into the intake pipe.

  The EGR device 10 constituting the exhaust emission control device 1 according to the present embodiment takes out a part of the exhaust gas from the exhaust pipe downstream of the turbine and returns the exhaust gas into the intake pipe upstream of the compressor (LP-EGR). ) Device. As shown in FIG. 1, the exhaust purification device 1 (EGR device 10) includes an EGR passage 11, an EGR valve 12, a housing 13, and a differential pressure sensor 14.

  The EGR passage 11 connects an exhaust pipe downstream of the turbine and an intake pipe upstream of the compressor. As a result, a part of the exhaust gas is taken out from the exhaust pipe downstream of the turbine, and the exhaust gas is recirculated into the intake pipe upstream of the compressor. The EGR passage 11 includes an EGR pipe 110 that extends upward from a lower exhaust pipe and then bends greatly toward the intake pipe, and an EGR valve passage 130 formed in the housing 13 described later.

  Further, the EGR passage 11 has a hanging structure in which the EGR valve passage 130 is inclined downward as it goes to the connection portion with the intake pipe. As a result, the blow buoy pool and the condensed water pool in the EGR passage 11 and the EGR valve passage 130 and freezing associated therewith are avoided.

  The EGR valve 12 is provided in the middle of the EGR valve passage 130. Specifically, the EGR valve 12 is provided in the middle of the hanging structure portion of the EGR valve passage 130 and is disposed above the intake pipe. The EGR valve 12 is connected to the ECU via an actuator (not shown). The EGR valve 12 controls the flow rate of the exhaust gas recirculated from the exhaust pipe to the intake pipe when the valve opening degree is electromagnetically controlled by the ECU.

  The housing 13 has the EGR valve passage 130 formed therein. Further, the housing 13 stores the EGR valve 12 in the middle of the EGR valve passage 130.

  The differential pressure sensor 14 detects a pressure difference between the upstream side and the downstream side of the EGR valve 12 in the EGR passage 11. The differential pressure sensor 14 includes a differential pressure sensor main body 140, a first pressure detection unit 141, a second pressure detection unit 142, and a differential pressure detection passage 143.

  The differential pressure sensor main body 140 is provided outside the upstream side of the EGR passage 11. More specifically, the differential pressure sensor main body 140 is disposed above the curved portion of the EGR pipe 110.

  The first pressure detector 141 is provided on the upstream side of the EGR passage 11. More specifically, the first pressure detector 141 is disposed below the differential pressure sensor main body 140 in the vicinity of the curved portion of the EGR pipe 110. The first pressure detection unit 141 is connected to the differential pressure sensor main body 140 by a first pipe 141a. Thereby, a pressure difference between the first pressure detection unit 141 and a second pressure detection unit 142 described later is detected.

  The differential pressure detection passage 143 is formed in the housing 13. The differential pressure detection passage 143 is connected to the downstream side of the EGR passage 11 via a connection passage 144. As a result, a part of the exhaust gas flows through the differential pressure detection passage 143 from the downstream side toward the upstream side. The differential pressure detection passage 143 and the connection passage 144 will be described in detail later.

  The second pressure detection unit 142 is provided on the upstream side of the differential pressure detection passage 143. More specifically, the second pressure detection unit 142 is disposed below the differential pressure sensor main body 140 in the vicinity of the first pressure detection unit 141. The second pressure detector 142 is connected to the differential pressure sensor main body 140 by a second pipe 142a.

Next, the differential pressure detection passage 143 and the connection passage 144 will be described in detail.
As shown in FIG. 2, the differential pressure detection passage 143 is formed along the EGR valve passage 130 in the housing 13 on the side and below the EGR valve passage 130. Further, as shown in FIGS. 2 and 3, the differential pressure detection passage 143 is inclined downwardly from the second pressure detection unit 142 side toward the connection passage 144 side. As a result, the blow biole reservoir, the condensed water reservoir and the accompanying freezing in the differential pressure detection passage 143 are avoided.

  As shown in FIGS. 2 and 4, the connection passage 144 is formed to extend outward from the side of the EGR valve passage 130. The width of the tip is gradually reduced, and the tip is tapered. The connection passage 144 communicates with the above-described differential pressure detection passage 143. Accordingly, a part of the exhaust gas introduced into the connection passage 144 from the EGR passage 11 (EGR valve passage 130) is introduced into the differential pressure detection passage 143 and flows into the second pressure detection unit 142.

  As shown in FIG. 4, the connection passage 144 is inclined downward in the housing 13 from the differential pressure detection passage 143 side toward the EGR passage 11 (EGR valve passage 130). In the present embodiment, the lowermost end portion 145 of the connection passage 144 is located at the lowermost end portion of the EGR passage 11 to which the connection passage 144 is connected, as shown in FIG. As a result, the blow bioy pool, the condensed water pool and freezing associated therewith in the connection passage 144 are avoided.

The effect of this embodiment will be described with reference to FIGS.
Here, FIG. 5 is a schematic diagram of the exhaust purification apparatus 1 according to the present embodiment. FIG. 6 is a schematic diagram of a conventional exhaust purification device 1A.

In the present embodiment, as is apparent from the schematic diagram of FIG. 5, a differential pressure detection passage 143 is provided inside the housing 13, and the first pressure detection unit 141 and the second pressure are provided upstream of the EGR valve 12. The detection part 142 was integrated. This eliminates the need to provide the differential pressure detection passage 143 and the wiring components outside the EGR passage 11 as compared with the conventional exhaust purification device 1A of FIG.
In addition, since the differential pressure detection passage 143 is provided inside the housing 13, the mounting position of the differential pressure sensor main body 140 can be made lower than in the prior art. As a result, the height of the vehicle bonnet (not shown) can be lowered, and a pedestrian protection line can be secured. Therefore, according to this embodiment, more compact packaging is possible.

  In the present embodiment, the differential pressure detection passage 143 is provided so as to be inclined downward from the second pressure detection unit 142 side toward the connection passage 144 side. As a result, it is possible to prevent accumulation of blow biole and condensate in the differential pressure detection passage 143 and freezing associated therewith, and to detect the differential pressure with high accuracy and to control the EGR valve 12 with high accuracy, while packaging the apparatus. Can be improved.

  In the present embodiment, the connection passage 144 that connects the EGR passage 11 and the differential pressure detection passage 143 is formed in the housing 13 so as to be inclined downward from the differential pressure detection passage 143 side toward the EGR passage 11 side. . Thereby, it is possible to prevent a blow bioy pool or a condensed water pool and freezing associated therewith in the connection path 144 connecting the EGR path 11 and the differential pressure detection path 143, and the above-described effects are more remarkably exhibited.

  In the present embodiment, the lowermost end portion 145 of the connection passage 144 is disposed at the lowermost end portion in the axial position of the EGR passage 11 to which the connection passage 144 is connected. Thereby, since the position of the connection passage 144 connecting the differential pressure detection passage 143 and the EGR passage 11 can be arranged at the lowest position, the mounting position of the differential pressure sensor main body 140 can be further lowered, and a more compact packaging can be achieved. It becomes possible.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Exhaust gas purification device 11 ... EGR passage 12 ... EGR valve 13 ... Housing 14 ... Differential pressure sensor 140 ... Differential pressure sensor main body 141 ... First pressure detection part 142 ... Second pressure detection part 143 ... Differential pressure detection passage 144 ... Connection passage 145 ... Bottom end of connection passage X ... Center axis of EGR passage

Claims (4)

An exhaust gas purification device that is provided in an exhaust system of an internal combustion engine and purifies exhaust gas of the internal combustion engine,
An EGR passage that recirculates part of the exhaust gas flowing through the exhaust passage of the internal combustion engine to the intake passage of the internal combustion engine;
An EGR valve provided in the EGR passage for controlling a flow rate of exhaust gas recirculated from the exhaust passage to the intake passage;
A housing in which the EGR passage is formed and which stores the EGR valve;
A differential pressure sensor for detecting a pressure difference between the upstream side and the downstream side of the EGR valve in the EGR passage,
The differential pressure sensor is
When one of the upstream side and the downstream side of the EGR valve is one side and the other is the other side,
A differential pressure sensor main body provided outside the one side of the EGR passage;
A first pressure detector provided on the one side of the EGR passage and connected to the differential pressure sensor main body;
A differential pressure detecting passage formed in the housing and connected to the other side of the EGR passage via a connecting passage;
An exhaust gas purification apparatus for an internal combustion engine, comprising: a second pressure detection unit provided on the opposite side of the connection passage in the differential pressure detection passage and connected to the differential pressure sensor main body.   2. The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the differential pressure detection passage is inclined downwardly from the second pressure detection unit side toward the connection passage side.   The exhaust purification device for an internal combustion engine according to claim 1 or 2, wherein the connection passage is inclined downward from the differential pressure detection passage side toward the EGR passage side in the housing.   The exhaust gas purification apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein a lowermost end portion of the connection passage is located at a lowermost end portion in a position in a central axis direction of the EGR passage to which the connection passage is connected. .

Images