JP2019127903A - Exhaust emission control device of engine - Google Patents

Abstract

To provide an exhaust emission control device of an engine which can properly detect exhaust pressure by suppressing a thermal influence of the engine or the like with respect to even a so-called longitudinal engine.SOLUTION: An exhaust emission control device of an engine is arranged in an exhaust passage 5a of the multicylinder engine 3 in which a plurality of cylinders is aligned in a vehicle fore-and-aft direction. The exhaust emission control device comprises an exhaust emission purification converter 51 including a DPF 53 arranged at an exhaust system side face 3c of the engine 3, and a pressure difference sensor 57 for detecting the fore-and-aft pressure of the DPF 53. The pressure difference sensor 57 comprises a sensor main body 571, and a pair of pressure pipes 572, 573 which are connected to an upstream-side pipe part 532 and a downstream-side pipe part 533 of the DPF 53 at their one-side end parts, respectively, and connected to the sensor main body 571 at the other end parts. The sensor main body 571 is attached to a front face upper part of the engine 3.SELECTED DRAWING: Figure 5

Description

  The present invention is an exhaust gas purification apparatus provided in the exhaust passage of a so-called vertical engine, in which a plurality of cylinders are arranged in the longitudinal direction of the vehicle, and in particular, particulates for collecting particulates contained in the exhaust gas of the engine. The present invention relates to an exhaust purification system of an engine provided with a filter.

  The vehicle is provided with an exhaust purification device in the exhaust passage of the engine in order to purify the exhaust gas of the engine. Among the exhaust gas purification devices, as shown in, for example, Patent Document 1, an exhaust gas purification device provided in an exhaust passage of a so-called exhaust supercharger-equipped horizontal engine is known. This exhaust gas purification apparatus includes an exhaust gas purification converter that includes an oxidation catalyst and a DPF (diesel particulate filter) and is attached to a side surface (specifically, a rear surface) of the engine exhaust system side, and an upstream side and a downstream side of the DPF. A differential pressure for detecting a differential pressure (a differential pressure across DPF) of a pair of exhaust pressure detection pipes for detecting pressure and a pair of exhaust pressure detection pipes attached to a cowl panel located at the upper rear of the engine And a sensor main body.

  In the exhaust gas purification device described in Patent Document 1, since the exhaust gas purification converter is attached to the side surface of the exhaust system of the engine, it can be warmed by the heat of the engine and can introduce the high temperature exhaust gas as it is. This is advantageous for exhaust gas purification.

  Moreover, since the exhaust pressure detection pipe extends upward toward the rear of the vehicle while avoiding the turbine of the exhaust turbocharger and is connected to the differential pressure sensor main body attached to the cowl panel, the engine can be used to detect the exhaust pressure. It is also advantageous in that the thermal influence of the exhaust turbocharger can be suppressed and the detection accuracy can be enhanced.

JP 2007-85292 A

  By the way, the exhaust gas purification device described in Patent Document 1 is applied to a so-called horizontal engine in which a plurality of cylinders are arranged in the vehicle width direction, and a plurality of cylinders are arranged in the vehicle longitudinal direction. When applied to a so-called vertical engine as it is, there is a concern that the detection accuracy of the differential pressure sensor main body may be lowered.

  That is, the vertical engine is longer in the vehicle front-rear direction than the horizontal engine. For this reason, when this vertically mounted engine is installed in a limited engine room, the distance between the cowl panel to which the differential pressure sensor main body is attached and the engine will be close, and the effects of radiant heat from the engine will be affected by the horizontally mounted engine. It becomes bigger than.

  Moreover, since the differential pressure sensor main body is disposed on the rear side of the engine, the thermal influence due to the air flow (running wind) whose temperature has been raised by the engine can not be ignored.

  As described above, when the conventional exhaust purification device is applied to a vertical engine as it is, the thermal influence on the differential pressure sensor main body by the engine cannot be ignored, and there is a concern that the detection accuracy may be lowered depending on the operating region of the engine. there were.

  In view of the above problems, an object of the present invention is to provide an engine exhaust purification device capable of appropriately detecting exhaust pressure while suppressing the thermal influence of an engine or the like even for a so-called vertical engine. Do.

  In order to solve the above problems, an exhaust gas purification apparatus for an engine according to the present invention is an exhaust gas purification apparatus provided in an exhaust passage of a multi-cylinder engine in which a plurality of cylinders are aligned in the longitudinal direction of a vehicle. The exhaust system includes an exhaust purification converter including a particulate filter disposed on a side surface of the exhaust system, and a pressure sensor for detecting a front-rear pressure of the particulate filter, wherein the pressure sensor includes a sensor body and one end upstream of the particulate filter. And a pair of exhaust pressure pipes each connected to the exhaust passage on the side and the downstream side and having the other end connected to the sensor main body, the sensor main body being attached to the front of the engine.

  According to the present invention, since the exhaust gas purification converter including the particulate filter is disposed on the side of the exhaust system of the engine, the exhaust gas purification converter can be warmed by the heat of the engine and introduce high temperature exhaust gas as it is. And exhaust gas purification can be performed efficiently. Moreover, since the sensor body of the pressure sensor is attached to the front of the engine via the pair of exhaust pressure pipes, it is exposed to the air flow entering the engine room to be cooled, and on the air flow upstream side of the engine Since it will be located, the temperature rise can be suppressed effectively. For this reason, even in the vertically mounted engine, in the pressure sensor including the sensor main body and the exhaust pressure pipe, the thermal influence from the engine can be suppressed as much as possible, and the detection accuracy can be maintained. .

  In the present invention, the specific configuration of the exhaust gas purification converter and the arrangement position of the converter on the side surface of the exhaust system are not particularly limited. For example, housings of an oxidation catalyst and a particulate filter are integrally formed and both are exhaust gas The exhaust gas purification converter or the like may be arranged in series along the flow direction, and the exhaust gas purification converter may include the particulate filter disposed on the side of the exhaust system of the engine, and the upstream side of the particulate filter The particulate filter and the oxidation catalyst are mounted in parallel in the vertical direction of the vehicle on the front side of the vehicle on the side surface of the exhaust system. Is preferred.

  If comprised in this way, exhaust gas can be appropriately purified by a particulate filter and an oxidation catalyst. Moreover, since the particulate filter and the oxidation catalyst are attached in parallel in the vehicle vertical direction on the vehicle front side on the exhaust system side face, a pair connected to the exhaust passage on the upstream side and the downstream side of the particulate filter The path of the exhaust pressure pipes can also be set short, and these exhaust pressure pipes can be easily routed.

  In this case, the particulate filter may be disposed above the oxidation catalyst, but the particulate filter is preferably disposed below the oxidation catalyst.

  According to this structure, heat can be transferred from the particulate filter to the oxidation catalyst, whereby the oxidation catalyst can be efficiently activated, and purification performance can be improved.

  In the present invention, the piping path of the pair of exhaust pressure pipes is not particularly limited. For example, when the particulate filter is disposed along the longitudinal direction of the vehicle, the piping path of one exhaust pressure pipe However, the rear exhaust pressure pipe disposed on the vehicle rear side of the pair of exhaust pressure pipes may be a pipe between the exhaust purification converter and the exhaust system side surface of the engine. It is preferable that piping is provided along the longitudinal direction of the vehicle on the outer side in the vehicle width direction of the exhaust gas purification converter, and is provided along the vehicle width direction in front of the exhaust gas purification converter.

  If comprised in this way, the rear side exhaust pressure pipe | tube arrange | positioned at the vehicle rear side is piped along the vehicle front-back direction in the vehicle width direction outside of the said exhaust purification converter, ie, the inner side opposite to an engine. Therefore, the thermal influence from the engine is reduced. In addition, by making the rear exhaust pressure pipe detour outside the exhaust purification converter in the vehicle width direction and piping, the pressure pipe portion piped in front of the exhaust purification converter can be set to be relatively long. And since this rear side exhaust pressure pipe is piped along the vehicle width direction in front of the exhaust purification converter, it can be exposed to the traveling wind at the front piping portion, thereby the heat of the exhaust pressure pipe itself The detection effect can be reduced and the detection accuracy can be improved.

  In this case, the specific piping route of the pressure pipe portion (the front piping portion of the rear exhaust pressure pipe) which is piped in front of the exhaust gas purification converter is not particularly limited either, but the exhaust gas purification converter The fuel cell system further includes a thermal protector disposed in front of the particulate filter and configured to include a heat insulating material, and a front piping portion of the rear exhaust pressure pipe interposes the thermal protector against the particulate filter. It is preferable to be piped in a state where it is allowed to

  According to this structure, the thermal influence from the converter main body including the particulate filter can be suppressed as much as possible for the front piping portion, and the thermal influence of the rear exhaust pressure pipe can be effectively achieved. The detection accuracy can be further reduced and the detection accuracy can be further improved.

  In the present invention, the specific configuration of the engine provided with the exhaust emission control device and the relative positional relationship with the specific configuration are not particularly limited. For example, the engine includes an upper cover member that covers an upper portion thereof, The upper cover member has a ceiling wall disposed above the engine, and a front wall including an opening opening forward and extending downward from a front end of the ceiling, and the sensor main body includes: It is preferable to be attached to the upper part of the engine behind the opening.

  That is, in order to secure the design of the engine, an upper cover member may be provided, and the upper cover member covers the upper portion of the engine at least in a predetermined range. For this reason, when the sensor main body is attached to the front upper part of the engine covered with the upper cover member, there is a concern about the reduction of the cooling effect by the traveling wind. However, when the upper cover member is provided with the opening as described above and the sensor main body is attached to the front upper part of the engine facing the front and rear in this opening, the reduction of the cooling effect by the upper cover member is avoided to ensure detection accuracy. Can be maintained.

  According to the present invention, even in a vertically mounted engine, in the pressure sensor including the sensor main body and the exhaust pressure pipe, the thermal influence from the engine can be suppressed as much as possible, and its detection accuracy is appropriate. Can be maintained in a state.

It is a mimetic diagram showing a schematic structure of an engine system in vehicles concerning this embodiment. 1 is a schematic front view showing an engine equipped with an exhaust emission control device according to the present embodiment. FIG. 2 is a schematic side view showing the engine with the upper cover removed. It is a schematic perspective view which shows the exhaust gas purification apparatus which concerns on this embodiment with an engine. It is a general | schematic partial expansion perspective view which shows the same exhaust gas purification apparatus with an engine. It is a schematic sectional drawing in the VI-VI line of FIG. It is a schematic side view showing the sensor main part concerning this embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The exhaust gas control apparatus of the present embodiment will be described based on the exhaust gas control apparatus provided in the exhaust passage of a six-cylinder in-line diesel engine in which six cylinders are arranged in a line in the longitudinal direction of the vehicle. The exhaust purification device can also be applied to the exhaust passage of other engines such as a 4-cylinder in-line gasoline engine.

  In addition, although "F" "Re" "U" "D" "L" "Ri" which shows a direction is shown for convenience of explanation in some drawings, these directions are the front of a vehicle, and a back. , Up, down, left and right directions are shown.

[Overall configuration of engine system]
The schematic configuration of a multi-cylinder engine system will be described with reference to FIG.

  As shown in FIG. 1, a vehicle 1 according to the present embodiment includes an engine system 2 mounted on the vehicle 1 and an ECU (Engine Control Unit) (not shown) that executes drive control of the engine system 2. Have.

  The engine system 2 includes an engine 3, an intake device 4, and an exhaust device 5. In the present embodiment, as described above, a multi-cylinder diesel engine having six cylinders 3 a is employed as an example of the engine 3.

  The intake device 4 has an intake passage 4 a connected to an intake port (not shown) of the engine 3. An air cleaner 42 is provided at the upstream end of the intake passage 4a, and fresh air passes through the air cleaner 42 and is taken into the intake passage 4a.

  The compressor 61 of the turbocharger 6, the throttle valve 43, the intercooler 44, and the surge tank 45 are interposed in the intake passage 4a. The air having flowed through the intake passage 4 a is supercharged by the compressor 61 of the turbocharger 6 and is sent to the intercooler 44 through the throttle valve 43. The intercooler 44 cools the air whose temperature has been increased by supercharging by the compressor 61.

  The surge tank 45 is provided immediately before the connection portion with the intake port (not shown) of the engine 3 and is provided for leveling the amount of air flowing into each of the cylinders 3a to 3f.

  The exhaust device 5 has an exhaust passage 5 a connected to an exhaust port (not shown) of the engine 3. A turbine 62 of the turbocharger 6, an exhaust purification device 50, an exhaust shutter valve 54, and a silencer 55 are interposed in the exhaust passage 5a.

  The exhaust purification device 50 includes an exhaust purification converter 51 including a DOC (diesel oxidation catalyst) 52 and a DPF (diesel particulate removal filter) 53, and a differential pressure sensor 57. DOC 52 (corresponds to the oxidation catalyst) is made harmless by oxidizing CO and HC in the exhaust gas discharged from the engine 3 and DPF 53 (corresponds to the particulate filter) is contained in the exhaust gas It collects fine particles such as soot. The differential pressure sensor 57 detects the differential pressure across the DPF 53. A specific configuration of the exhaust purification device 50 will be described later.

  The exhaust shutter valve 54 is provided between the DPF 53 of the exhaust purification converter 51 and the silencer 55 in the flow direction of the exhaust gas, and is a valve that controls the flow rate of the exhaust gas exhausted to the outside through the silencer 55.

  The turbocharger 6 includes the compressor 61 and the turbine 62. The turbine 62 is rotated by receiving energy of exhaust gas flowing through the exhaust passage 5a, and the compressor 61 is rotated in conjunction with the rotation of the turbocharger 62. The air flowing through the intake passage 4a is compressed (supercharged).

  The engine system 2 further includes an HP-EGR (High Pressure-Exhaust Gas Recirculation) device 7, an LP-EGR (Low Pressure-Exhaust Gas Recirculation) device 8, and a blow-by gas device 9. The HP-EGR device 7 has an HP-EGR passage (EGR passage) 71. The HP-EGR passage 71 is provided to connect a portion of the exhaust passage 5a upstream of the turbine 62 and a portion of the intake passage 4a downstream of the intercooler 44 in the exhaust passage 5a. The discharged exhaust gas having a relatively high pressure is recirculated to the intake side. An EGR valve 72 is inserted in the HP-EGR passage 71. The EGR valve 72 is a valve for adjusting the amount of exhaust gas recirculated to the intake passage 4a.

  The LP-EGR device 8 has an LP-EGR passage 81. The LP-EGR passage 81 includes the exhaust passage 5a between the portion where the DPF 53 is inserted and the portion where the exhaust shutter valve 54 is inserted, the portion where the air cleaner 42 is inserted, and the compressor of the turbocharger 6 A portion 61 is provided so as to connect with the intake passage 4a, and the relatively low pressure exhaust gas discharged to the exhaust passage 5a is returned to the intake side.

  An EGR cooler 82 and an EGR valve 83 are interposed in the LP-EGR passage 81. The EGR valve 83 is a valve for adjusting the amount of exhaust gas to be recirculated to the intake passage 4a, similarly to the EGR valve 72 in the HP-EGR device 7. The EGR cooler 82 is provided to cool the exhaust gas recirculated to the intake passage 4a.

  The blowby gas apparatus 9 has a blowby gas passage 91. The blow-by gas passage 91 is provided so as to connect the inside of the head cover of the engine 3 and the intake passage 4a. The blowby gas passage 91 is a passage for returning the blowby gas generated in the engine 3 to the intake passage 4a.

[Specific configuration of engine 3]
The specific configuration of the engine 3 will be described using FIGS. 2 and 3. FIG. 2 is a schematic front view of the engine system 2 as viewed from the front, and FIG. 3 is a schematic side view of the engine system 2 as viewed from the right side.

  In the engine system 2, the engines 3 are arranged such that the cylinder row direction is along the longitudinal direction of the vehicle (see FIG. 1). A part of the intake device 4 is disposed on one side surface of the engine 3 in the vehicle width direction (the left side surface of the engine 3 in the illustrated example), and exhaust purification is performed on the other side surface in the vehicle width direction (the right side surface of the engine 3 in the illustrated example). A part of the exhaust device 5 including the device 50 is arranged. Hereinafter, one side in the vehicle width direction of the engine 3 may be referred to as an intake side 3b, and the other side may be referred to as an exhaust side 3c. In the present embodiment, the right side surface of the engine 3 is set as the exhaust system side surface 3c. However, when the exhaust device 5 is arranged on the left side surface of the engine 3, this left side surface is used as the exhaust system side surface. It is set.

  The engine 3 has a cylinder block 31 in which a vertically extending cylinder 3a (see FIG. 1) is formed, a cylinder head 32 provided so as to cover an upper opening of the cylinder 3a, and a lubricant oil. The upper cover 34 (upper cover) covers the upper side of the cylinder head 32 in a predetermined range including an oil pan 33 disposed below the cylinder block 31 and a part of the intake device 4 and a part of the exhaust device 5. Corresponding to the member).

  The upper cover 34 is for concealing a complicated internal structure including the engine 3 and the like to improve the design. The upper cover 34 has a top wall portion 341 disposed above the cylinder head 32 and a peripheral side wall 342 extending downward from the outer peripheral edge of the top wall portion, and is configured in a reverse tray shape as a whole.

  In the present embodiment, the top wall portion 341 is disposed so as to incline downward toward the front of the vehicle, and is configured in a substantially hexagonal shape in which the rear portion in the vehicle longitudinal direction gradually shrinks toward the rear in plan view. . The circumferential wall 342 has a front wall 344 extending downward from the front end edge of the top wall 341, side walls 345 extending downward from both left and right edges of the top wall 341, and a rear end edge of the top wall 341 downward. And a rear wall portion 346 extending.

  The front wall portion 344 has an opening 344a that opens forward, and the traveling air can be taken into the gap between the engine 3 and the upper cover 34 through the opening 344a. In the present embodiment, the opening 344a is configured as a notch extending upward from the lower end of the front wall 344 and is formed with a predetermined length from the center in the vehicle width direction of the front wall 344 toward the right. There is. The opening 344a is largely cut upward at the center of the front wall 344, and is set so that the depth of cut gradually decreases toward the right at the right end. The rear wall portion 346 is formed in accordance with the shape of the rear end edge of the top wall portion 641 in the present embodiment, and has a pair of left and right inclined rear wall portions 346a inclined rearward toward the inside of the vehicle and a pair of left and right inclinations. A central rear wall (not shown) is disposed between the walls 346a and extends parallel to the front wall 344. A central portion of the central rear wall portion in the vehicle width direction is cut out by a predetermined length along the vehicle width direction (not shown) in the same manner as the front wall portion 344, and is taken in from an opening 344a of the front wall portion 344. It is supposed to distribute the running wind smoothly.

  Fresh air flows into the engine 3 through an intake passage 4a connected to the upper portion of the intake system side surface 3b (see FIG. 1).

  On the other hand, the exhaust gas discharged from the engine 3 is turbocharged attached to the upper end portion of the exhaust system side surface 3c through the exhaust passage 5a (see FIG. 1) connected to the upper portion of the exhaust system side surface 3c of the engine 3 After flowing into the machine 6, it flows into the exhaust purification device 50.

[Specific Configuration of Exhaust Purification Device 50]
The exhaust purification device 50 includes the exhaust purification converter 51 and the differential pressure sensor 57 as described above. FIG. 4 is a schematic perspective view showing the exhaust gas purification apparatus together with the engine, and FIG. 5 is a schematic partial perspective view when it is enlarged and seen from a different angle from FIG. In FIG. 5, a sensor main body 571 described later is omitted.

<< Specific Configuration of Exhaust Purification Converter 51 >>
The exhaust purification converter 51 includes the DOC 52, the DPF 53 connected to the downstream end of the DOC 52 in the exhaust gas flow direction, and a thermal damage protector 58 that covers a part of the connecting portion 51a. As shown in FIG. 3, it is disposed adjacent to the exhaust system side surface 3 c of the engine 3. In the present embodiment, the DOC 52 and the DPF 53 are directly connected, but a connection pipe may be interposed between the two 52 and 53.

  As described above, the DOC 52 oxidizes HC and CO in the exhaust gas, and has, for example, a honeycomb cordierite support in which a noble metal catalyst is coated. As shown in FIG. 3, the DOC 52 includes a substantially cylindrical catalyst main body 521 in which the carrier is accommodated, an upstream pipe portion 522 connected to the upstream end of the catalyst main body 521, and a downstream of the catalyst main body 521. And a downstream pipe portion 523 connected to the side end portion, and exhaust gas discharged from the turbine 62 of the turbocharger 6 is introduced.

  The upstream side pipe portion 522 is configured in a funnel shape that gradually increases in diameter toward the downstream side. The upstream end of the upstream side pipe portion 522 has a flange portion 522a, and the flange portion 522a is connected to the turbine 62 of the turbocharger 6. The downstream pipe portion 523 is configured in a funnel shape that gradually decreases in diameter toward the downstream side. The downstream side pipe portion 523 is bent downward from a direction substantially along the longitudinal direction of the vehicle (strictly, a direction inclined forward and downward) at an intermediate portion, and the exhaust gas is guided to the lower side of the DOC 52. A flange portion 523 a is provided at the downstream end of the downstream side pipe portion 523, and the flange portion 523 a is connected to the flange portion 532 b of the DPF 53 with a bolt 511. As clearly shown in FIG. 6, the flanges 523a and 532b constitute the connecting portion 51a of the exhaust purification converter 51.

  The DOC 52 having the above-described configuration is attached to the engine 3 or the like on the vehicle front side of the exhaust system side surface 3c of the engine 3. Specifically, the DOC 52 is adjacent to one side surface (right side surface in the illustrated example) of the cylinder head 32 including the head cover in the vehicle width direction. As shown in FIG. 3, the upstream side pipe portion 522 of the DOC 52 is disposed to correspond to the center front of the cylinder head 32 in the front-rear direction of the vehicle. Further, the catalyst main body 521 is disposed so that the central axis is substantially along the longitudinal direction of the vehicle, and in the present embodiment, is disposed so as to be slightly inclined downward toward the front of the vehicle. Further, the downstream side pipe portion 523 is disposed corresponding to the front end portion of the cylinder head 32 in the vehicle longitudinal direction. More specifically, the front end portion of the downstream side pipe portion 523 is disposed in such a manner as to project from the front end surface of the cylinder head 32 to the front of the vehicle.

  Next, the DPF 53 will be described with reference to FIGS.

  As described above, the DPF 53 collects fine particles such as soot contained in the exhaust gas, and has, for example, a honeycomb-shaped wall flow type cordierite filter inside. The DPF 53 is connected to a substantially square tubular filter main body 531 in which the filter is accommodated, an upstream pipe portion 532 connected to the upstream end of the filter main body 531, and a downstream end of the filter main body 531 The downstream side pipe part 533 is provided, and the full length along the longitudinal direction is set longer than the full length of the DOC52.

  The upstream pipe portion 532 is configured in a funnel shape in which the cross-sectional area gradually expands toward the downstream side. Specifically, the upstream side tube portion 532 is bent in the middle, and one end is opened upward and the other end is opened upstream in the vehicle rear side, and the upper opening edge portion of the upstream side tube main body 532a An upstream connection boss 532c having a flange 532b provided at one end opening edge and connected to the flange 523a of the DOC 52, and a hole (not shown) protruding from the upstream pipe main body 532a and communicating with the internal space The exhaust gas pressure immediately before the filter main body 531 can be taken out through the hole of the connection boss 532c.

  Specifically, as clearly shown in FIG. 2, the upstream side connection boss portion 532 c is provided on the inner side surface in the vehicle width direction of the upstream side pipe main body 532 a and in the middle portion in the vehicle vertical direction. The protruding direction of the connection boss portion 532c is inclined forward in the vehicle with respect to the inner side in the vehicle width direction in this embodiment, so as to facilitate connection work of an upstream pressure pipe 572 (corresponding to an exhaust pressure pipe) described later. It is done.

  On the other hand, the downstream side pipe portion 533 is configured in a funnel shape whose cross-sectional area gradually reduces toward the downstream side. Specifically, the downstream side pipe portion 533 has a downstream side pipe main body 533a whose center of the downstream side opening is offset downward with respect to the center of the upstream side opening, and a downstream side pipe main body 533a. A downstream connection boss 533 b having a hole (not shown) communicating with a space is provided, and the pressure of exhaust gas immediately after the filter main body 531 can be extracted through the hole of the connection boss 533 b. A connection pipe 5 b is connected to the downstream end of the downstream pipe portion 533, and is connected to a flexible pipe 5 c disposed on the rear side of the engine 3 via the connection pipe 5 b.

  The downstream connection boss 533b is, as clearly shown in FIGS. 3 and 4, an outer surface of the downstream pipe main body 533a in the vehicle width direction, and is provided at the upper end in the vehicle vertical direction. In the present embodiment, the protrusion direction of the connection boss portion 533b is set to be inclined in a direction having three components of the rear in the vehicle longitudinal direction, the outer side in the vehicle width direction and the upper component in the vehicle vertical direction. The side pressure pipe 573 is set so as to be easily handled.

  The DPF 53 having the above configuration is attached to the engine 3 or the like via a bracket (not shown) on the vehicle front side of the exhaust system side surface 3c of the engine 3.

  Specifically, as clearly shown in FIG. 2, the DPF 53 is disposed adjacent to the exhaust system side surface 3 c of the engine 3 in parallel with the DOC 52 in the vertical direction of the vehicle. That is, the DPF 53 is disposed below the DOC 52 in the vertical direction of the vehicle, from the center in the height direction of the cylinder block 31 to the lower end of the cylinder head 32. At this time, the filter main body 531 of the DPF 53 and the catalyst main body 521 of the DOC 52 are substantially opposed in the vertical direction of the vehicle, and heat generation from the filter main body 531 is efficiently transferred to the catalyst main body 521 There is.

  Further, as clearly shown in FIG. 3, the DPF 53 is disposed such that the exhaust gas flow direction (the central axis direction of the filter main body 531) in the filter main body 531 is along the vehicle longitudinal direction. The front end portion of the pipe portion 532 is disposed in a manner projecting forward from the front end surface of the cylinder block 31 to the vehicle front, and the downstream end portion of the downstream side pipe portion 533 is disposed corresponding to the rear portion of the cylinder block 31 . At this time, the upstream side connection boss portion 532c is located on the vehicle front side with respect to the front end surface of the cylinder block 31, as shown in FIG.

  A part (front part) of the connection part 51 a between the DPF 53 and the DOC 52 is covered by the heat damage protector 58. That is, the heat protector 58 is disposed at least in front of the DPF 53 and the DOC 52 in close proximity thereto. The heat damage protector 58 has a heat insulating effect by being formed of a heat insulator, and the heat from the connecting portion 51a is not easily transmitted to the downstream pressure pipe 573 which is piped on the heat damage protector 58. 6 is a schematic cross-sectional view taken along line VI-VI in FIG.

  The heat damage protector 58 has an upper wall 581 disposed above the front portion of the connecting portion 51a, a front wall 582 extending downward from the front end edge of the upper wall 581, and the upper wall 581, as shown in FIG. It has a pair of left and right side walls 583 extending downward from the left and right side edges, and covers the front portion of the connecting portion 51a from the front, the upper side, and the left and right sides. The upper wall 581 has a substantially rectangular shape in plan view, and the rear end edge is cut out corresponding to the shape of the downstream side pipe portion 523 of the DOC 52, and is configured to follow the shape of the downstream side pipe portion 523 . As shown in FIG. 6, the front wall 582 is set higher than the thickness of the connecting portion 51a so as to cover the front of the connecting portion 51a. The side wall 583 is also set to be higher than the thickness of the connecting portion 51a similarly to the front wall 582, and is attached to the connecting portion 51a by a bolt 584 at the side wall 583 as shown in FIG.

<< Specific Configuration of Differential Pressure Sensor 57 >>
Next, the differential pressure sensor 57 will be described. As shown in FIG. 5, the differential pressure sensor 57 is connected to the sensor main body 571, one end of each of the connection bosses 532 c and 533 b on the upstream side and the downstream side of the DPF 53, and the other end of the sensor main body 571. And a pair of pressure pipes 572 and 573 connected to each other, and the pressure across the filter body 531 of the DPF 53 is detected through the pair of pressure pipes 572 and 573, and the differential pressure is measured. Of the pressure pipes 572 and 573, one having one end connected to the upstream pipe 532 of the DPF 53 is connected to the upstream pressure pipe 572 and one having one end connected to the downstream pipe 533 of the DPF 53 downstream. It may be called side pressure pipe 573.

  In the present embodiment, the sensor main body 571 detects a differential pressure (a differential pressure in the upstream and downstream exhaust passages 5a) of the filter main body 531 in the DPF 53, and more specifically, the upstream side of the filter main body 531 And the difference of the pressure taken out by a pair of pressure pipes 572 and 573 whose one end is connected to the exhaust passage 5a on the downstream side is detected (see FIG. 1). For example, in the sensor body 571, the internal space of the housing 571 a is partitioned into two spaces via the piezoresistive sensor chip, and one of the ends of the pressure pipes 572 and 573 is communicated with each space. The difference between the pressures taken out by the pipes 572 and 573 is detected by the sensor chip and output to the control circuit chip built in the housing 571a. The control circuit chip of the sensor body 571 is electrically connected to an ECU (not shown).

  FIG. 7 is a schematic side view showing this sensor body. The sensor body 571 includes the housing 571a and a pair of pressure input pipes 571b and 571c projecting downward from the housing 571a, as clearly shown in FIGS. The housing 571a has a substantially rectangular parallelepiped shape elongated in the vehicle width direction made of a resin material such as an epoxy resin. The pressure input pipes 571b and 571c are resin pipes having predetermined elasticity, and are attached to the housing 571a. The pressure input pipes 571b and 571c are formed in the shape of a crank projecting to the front side of the vehicle to facilitate piping connection work. In these pressure input pipes 571b and 571c, one input pipe 571b (right side in the left and right vehicle width direction in FIG. 2) is connected to the upstream pressure pipe 572 by a clip 571d, and the other input pipe 571c is downstream pressure pipe 573 Are connected by a clip 571d.

  The sensor body 571 is attached to the front surface of the engine 3 via a bracket 575. Specifically, as shown in FIG. 2, the sensor body 571 is attached to the upper end portion of the front surface of the engine 3, more specifically to the front surface of the cylinder head 32 and behind the opening 344 a of the upper cover 34 It arrange | positions so that it may be directly exposed to the driving | running | working wind which flows in through the opening part 344a. In the present embodiment, the sensor main body 571 is disposed behind the center in the left-right vehicle width direction in the opening 344a of the upper cover 34.

  As shown in FIG. 7, a bracket 575 for attaching the sensor body 571 to the engine 3 is formed by bending a flat plate made of metal. Specifically, referring also to FIG. 5, the bracket 575 is provided with a lower mounting piece 575a on which a mounting protrusion (not shown) protruding forward from the front surface of the cylinder head 32 is overlapped, and an upper side from the mounting piece 575a. And a main body attachment piece 575c extending upward from the upper end of the intermediate connection piece 575b, as shown in FIG. 5, with respect to the cylinder head 32 by a plurality of bolts 575d at the lower attachment piece 575a. Is fixed. A lower end portion of the intermediate connecting piece 575 b is bent obliquely forward along the mounting protrusion of the cylinder head 32. Further, the upper end portion of the intermediate connection piece 575b is also slightly bent forward, whereby a gap is provided between the main body attachment piece 575c and the front surface of the cylinder head 32. A nut 575f is disposed in the gap, and a bolt 575e (see FIG. 5) passing through the sensor body 571 disposed on the front surface of the body attachment piece 575c is screwed with the nut 575f and the sensor body 571 is attached to the body attachment piece It is attached to 575c. The intermediate connection piece 575 b and the main body attachment piece 575 c are both disposed apart from the front surface of the cylinder head 32. The body attachment piece 575c is provided with an opening (not shown) at a portion corresponding to the sensor chip in the housing 571a of the sensor body 571.

  Next, the pressure pipes 572 and 573 will be described.

  The pressure pipes 572 and 573 connect the DPF 53 and the sensor main body 571 as shown in FIG. 1, and the pressure of the exhaust passage 5a on the upstream or downstream side of the exhaust gas flow direction of the DPF 53 (strictly speaking, the filter main body 531) The sensor main body 571 is for inputting. In the present embodiment, as shown in FIG. 3, the DPF 53 is disposed along the longitudinal direction of the vehicle, and the upstream side of the exhaust gas flow direction is disposed on the front side of the vehicle with respect to the downstream side. 573 corresponds to a rear exhaust pressure pipe disposed on the vehicle rear side.

  In the present embodiment, the pressure pipes 572 and 573 have shape retention by being formed of pipes having a predetermined rigidity such as metal pipes, and the exhaust gas purification converter is provided only at one place between the DPF 53 and the sensor main body 571. It is supported by the T.51, and the heat conduction through the members from the exhaust gas purification converter 51 is eliminated as much as possible.

  As shown in FIG. 5, the upstream pressure pipe 572 has one end (lower end) connected to the upstream connection boss 532 c of the DPF 53 and the other end (upper end) connected to the pressure input pipe of the sensor body 571. 571b. Thus, the upstream pressure pipe 572 brings the internal space of the upstream pipe main body 532 a of the DPF 53 into communication with the internal space of the sensor main body 571. As clearly shown in FIG. 2, the piping path of the upstream pressure pipe 572 is generally in front of the engine 3 and extends in the vertical direction along the inner side surface in the vehicle width direction of the exhaust purification converter 51. More specifically, referring also to FIGS. 4 and 5, the upstream pressure pipe 572 protrudes inward in the vehicle width direction from the upstream connection boss 532c, and is bent upward at a bending portion 572a. The upstream pressure pipe 572 extends upward along the vehicle width direction inner side surface of the DPF 53, the inner side wall 583 of the heat damage protector 58, and the DOC 52 above the bent portion 572a, and the pressure input of the sensor body 571 It is connected to the tube 571b. The upstream pressure pipe 572 is supported only by the pipe bracket 577 fixed to the side wall 583 of the heat protection protector 58 in the middle except the both ends, and combined with the heat insulation effect of the heat protection protector 58, the exhaust purification converter 51 The heat conduction from is suppressed as much as possible.

  On the other hand, as shown in FIG. 5, the downstream pressure pipe 573 has one end (rear end) connected to the downstream connection boss 533 b of the DPF 53 and the other end (front end) connected to the sensor body 571. It is connected to the pressure input pipe 571c. Thus, the downstream pressure pipe 573 allows the internal space of the downstream pipe main body 533 a of the DPF 53 to communicate with the internal space of the sensor main body 571, and the sensor main body 571 is configured to detect the downstream pressure of the DPF 53. The piping path of the downstream pressure pipe 573 roughly bypasses the exhaust purification converter 51 outward in the vehicle width direction and extends in the longitudinal direction of the vehicle, and travels around the heat damage protector 58 to cross the front of the exhaust purification converter 51 It is set to extend upward afterward.

  More specifically, as shown in FIG. 4, the downstream pressure pipe 573 is provided with a side piping portion 573 a which is arranged along the longitudinal direction of the vehicle outside the exhaust purification converter 51 in the vehicle width direction, and the side piping portion A front piping portion 573b extending inward in the vehicle width direction from the front end portion of 573a and piping in front of the exhaust purification converter 51.

  As shown in FIG. 5, the side piping portion 573a is a first bent portion 573c provided at a position separated from the DPF 53, and a second bent portion 573d disposed in front of the first bent portion 573c and bent in a crank shape. And. The side piping portion 573a is bent forward in the vehicle from the projecting direction of the downstream connection boss portion 533b in the first bending portion 573c, and gently in the vehicle width direction outside (right side in the vehicle lateral direction) in the second bending portion 573d. It bends like a crank at a proper angle. As shown in FIG. 3, the side piping portion 573 a extends from the first bent portion 573 c to the heat protector 58 substantially in the longitudinal direction of the vehicle at a height position between the DOC 52 and the DPF 53.

  The front piping portion 573b is disposed along the heat protector 58 from the front end of the side piping portion 573a toward the inside in the vehicle width direction (see FIG. 6), and is provided at a position past the heat protector 58. The third bent portion 573e is bent upward and connected to the pressure input tube 571c of the sensor main body 571. Therefore, the front piping portion 573b is disposed in a state in which the heat damage protector 58 is interposed between the DOC 52 and the DPF 53. The front piping portion 573 b is supported by a pipe bracket 578 fixed to the inner edge in the vehicle width direction of the upper wall 581 of the heat damage protector 58. That is, the downstream pressure pipe 573 is supported only by the pipe bracket 578 provided on the upper wall 581 of the heat protection protector 58 in the middle except for the both ends, and the exhaustion combined with the heat insulation effect of the heat protection protector 58 The heat conduction from the purification converter 51 is suppressed as much as possible.

[Function effect]
In the exhaust gas purification device 50 for an engine configured as described above, the sensor body 571 of the differential pressure sensor 57 is attached to the upper part of the front surface of the cylinder head 32 of the engine 3. It can be located upstream of the air flow and can be exposed directly to the air flow before it is warmed by the engine 3 as well as the air flow flowing along the front of the engine 3.

  In particular, in the present embodiment, the upper cover 34 is provided to improve the design of the engine 3, but the upper cover 34 is provided with the opening 344a, and the sensor body 571 is provided with the opening 344a. Since it is attached to the front upper end portion of the engine 3 facing the front and rear, the traveling wind can be directly and efficiently guided to the sensor body 571.

  For this reason, the sensor body 571 of the differential pressure sensor 57 is cooled by the traveling air even if it is the vertically mounted engine 3, particularly the vertically mounted engine 3 having six cylinders 3 a and being relatively long back and forth. It is possible to suppress the thermal influence from the engine 3 as much as possible and to suppress the temperature rise effectively, whereby the detection accuracy of the differential pressure sensor 57 can be maintained with good.

  Furthermore, in the present embodiment, the downstream pressure pipe 573 has a side piping portion 573a and a front piping portion 573b, and the middle portion of the downstream pressure pipe 573 is a heat protector 58 in the front piping portion 573b. Since the downstream pressure pipe 573 itself is supported only through the pipe bracket 578, the thermal influence of the engine 3 and the exhaust gas purification converter 51 can be reduced.

  That is, since the side piping portion 573a of the downstream pressure pipe 573 is piped along the longitudinal direction of the vehicle outside the exhaust purification converter 51 in the vehicle width direction, the converter is located inside the exhaust purification converter 51 in the vehicle width direction The thermal influence from the engine 3 is reduced as compared with the case where piping is performed between the engine 51 and the exhaust system side 3 c of the engine 3. In addition, the front piping portion 573b extends inward in the vehicle width direction from the front end portion of the side piping portion 573a and is piped forward of the exhaust gas purification converter 51. Can be cooled by exposure to Moreover, by making the side piping portion 573a detour outside the exhaust purification converter 51 in the vehicle width direction and piping, the front piping portion 573b can be set relatively long, and the cooling effect in the front piping portion 573b is enhanced. be able to.

  In addition, the upstream pressure pipe 572 also extends in the vertical direction along the inner side of the exhaust purification converter 51 at a position separated from the inner side in the vehicle width direction of the exhaust purification converter 51. Since it is supported only via the pipe bracket 577 at 58, it can be cooled by directly exposing it to the air flow from the traveling wind, and the heat from the engine 3 and the exhaust gas purification converter 51 can be cooled also for the upstream pressure pipe 572 itself. Effect can be reduced.

  That is, in the exhaust gas control apparatus 50 for an engine according to the present embodiment, the thermal influence from the engine 3 and the exhaust gas purification converter 51 can be reduced also for the pressure pipes 572 and 573 themselves.

  As described above, in the engine exhaust purification apparatus 50 according to the present embodiment, the differential pressure sensor 57 including the sensor body 57 and the pressure pipes 572 and 573 can be cooled by being exposed to the traveling wind. The thermal influence can be suppressed as much as possible, and the detection accuracy can be maintained in an appropriate state.

  Furthermore, in the exhaust gas purification device 50, the exhaust gas purification converter 51 including the DOC 52 and the DPF 53 is disposed adjacent to the exhaust system side surface 3c of the engine 3 in the vehicle width direction. It is warmed by etc. Moreover, since the exhaust gas purification converter 51 is disposed on the exhaust system side surface 3 c of the engine 3, the exhaust gas path from the engine 3 to the exhaust gas purification converter 51 can be set short, and high temperature exhaust gas can be introduced as it is. it can. Therefore, the catalyst included in the exhaust gas purification converter 51 can be activated, and the exhaust gas can be efficiently purified.

  In particular, since the DPF 53 is disposed below the DOC 52, the DPF 53 can transfer heat from the DPF 53 to the DOC 52, whereby the DOC 52 can be efficiently activated, and the purification performance can be improved.

  Further, since the DOC 52 and the DPF 53 are attached in parallel in the vehicle vertical direction on the vehicle front side on the exhaust system side surface 3c, the path of the pair of pressure pipes 572 and 573 can be set short, and these pressure pipes 572 , 573 can be easily managed.

[Modification]
The engine exhaust purification device 50 described above is an embodiment of the engine exhaust purification device of the present invention, and the specific configuration thereof can be changed as appropriate without departing from the spirit of the present invention. . Hereinafter, the modification is demonstrated.

  (1) In the above embodiment, the diesel particulate filter (DPF 53) is described as an example of the particulate filter. However, any particulate filter may be applied to a gasoline particulate filter.

  (2) In the above embodiment, the DOC 52 and the DPF 53 have separate housings and are connected to each other. However, the oxidation catalyst carrier and the particulate collection filter are connected in series in a single cylindrical housing. It may be stored in an automatic manner.

  However, when the DOC 52 and the DPF 53 are configured as separate bodies by separate housings, the layout of the exhaust purification converter can be variously changed.

  (3) In the above embodiment, the exhaust gas purification converter 51 includes the DOC 52 and the DPF 53, and the DOC 52 and the DPF 53 are disposed at the lower side of the exhaust system side 3c of the engine 3 on the vehicle front side. Although arranged in parallel in the vehicle vertical direction, the arrangement of the exhaust purification converter is not particularly limited as long as it is arranged adjacent to the exhaust system side surface 3 c of the engine 3.

  For example, in a state where the central axis of the filter main body of the DPF in the exhaust purification converter is along the vehicle vertical direction (or along the oblique direction having the vertical component), the exhaust system side surface 3c of the engine 3 It may be arranged. In this case, since the exhaust passages on the upstream side and the downstream side of the filter body are both located on the vehicle front side in the exhaust system side surface 3c, the handling of the pressure pipe is facilitated.

  In the above embodiment, the DPF 53 is arranged so that the upstream pipe 532 of the DPF 53 is on the front side in the vehicle front-rear direction with respect to the downstream pipe 533, but the upstream pipe is the downstream pipe. The DPF may be arranged so as to be on the rear side in the vehicle front-rear direction. In this case, unlike the above embodiment, the upstream pressure pipe of the pressure pipes corresponds to the “rear exhaust pressure pipe”.

  Furthermore, the mutual positional relationship between the DOC 52 and the DPF 53 is not limited to the case where the DPF 53 is disposed below the DOC 52 as in the above-described embodiment, and vice versa, if these are configured as separate bodies. It may be arranged in parallel in the vehicle front-rear direction.

  However, if at least the particulate filter of the exhaust converter is disposed on the front side in the vehicle front-rear direction on the exhaust system side surface 3c of the engine 3 as in the above embodiment, the exhaust pressure pipe can be easily routed. preferable.

  (4) In the above embodiment, the differential pressure sensor 57 that directly detects the differential pressure across the DPF 53 is employed as the pressure sensor. However, if the pressure sensor can detect the differential pressure, its specific configuration is adopted. There is no particular limitation, and the pressure difference before and after the DPF 53 may be individually detected and the pressure difference may be calculated.

  (5) In the above embodiment, the pressure pipes 572 and 573 are connected to the upstream and downstream pipe portions 532 and 533 of the DPF 53, respectively, but one end portion of the exhaust pressure pipe exemplified by the pressure pipes 572 and 573 Is not limited to this embodiment, and if it is the exhaust passage 5a on the upstream side and the exhaust side of the DPF 53 (strictly, the filter main body 531), for example, the downstream side pipe portion 523 of the DOC 52 or the DPF 523 It may be connected to the connecting pipe 5b arranged on the downstream side.

  In short, one end of the exhaust pressure pipe may be connected to the upstream and downstream exhaust passages of the DPF 53 so that the filter main body 531 can be detected in the DPF 53.

  (6) Further, the piping path of the exhaust pressure pipe is not particularly limited as long as it can be connected to the sensor body disposed on the front surface of the engine 3 in the vehicle front-rear direction. For example, the rear exhaust pressure pipe may be piped along the vehicle front-rear direction between the exhaust purification converter and the exhaust system side face 3c of the engine from the viewpoint of shortening the pipe path.

3 Engine 3c Exhaust system side 34 Upper cover (corresponds to upper cover member)
344a Opening 5 Exhaust device 5a Exhaust passage 50 Exhaust gas purification device 51 Exhaust gas purification converter 52 DOC (Corresponding to oxidation catalyst)
53 DPF (compatible with particulate filter)
57 Differential pressure sensor (compatible with pressure sensor)
571 Sensor body 572 Upstream pressure pipe (corresponding to exhaust pressure pipe)
573 Downstream pressure pipe (corresponding to exhaust pressure pipe)
573a Side piping part 573b Front piping part 58 Heat damage protector

Claims (6)

An exhaust gas purification apparatus in which a plurality of cylinders are provided in an exhaust passage of a multi-cylinder engine in which a plurality of cylinders are arranged in the longitudinal direction of the vehicle
An exhaust purification converter including a particulate filter disposed on an exhaust system side of the engine;
And a pressure sensor for detecting the pressure before and after the particulate filter,
The pressure sensor includes a sensor body, and a pair of exhaust pressure pipes each having one end connected to the exhaust passage upstream and downstream of the particulate filter and the other end connected to the sensor body Prepared,
An exhaust purification system of an engine, wherein the sensor body is attached to the front of the engine. The exhaust purification converter includes the particulate filter disposed on an exhaust system side surface of the engine, and an oxidation catalyst disposed in the exhaust passage on the upstream side of the particulate filter and disposed on the exhaust system side surface of the engine. Prepared,
The exhaust gas purification device for an engine according to claim 1, wherein the particulate filter and the oxidation catalyst are disposed in parallel in the vertical direction of the vehicle on the front side of the vehicle on the side surface of the exhaust system.   The engine exhaust gas purification apparatus according to claim 2, wherein the particulate filter is disposed below the oxidation catalyst. The particulate filter is disposed along the longitudinal direction of the vehicle,
Of the pair of exhaust pressure pipes, a rear exhaust pressure pipe disposed on the rear side of the vehicle is piped along the vehicle front-rear direction on the outer side in the vehicle width direction of the exhaust purification converter, and in front of the exhaust purification converter. The exhaust gas purification apparatus for an engine according to any one of claims 1 to 3, wherein piping is performed along the vehicle width direction. The exhaust purification converter further includes a heat protector disposed in front of the particulate filter and configured to include a heat insulating material,
5. The engine exhaust purification system according to claim 4, wherein a front piping portion of the rear exhaust pressure pipe is piped with the thermal damage protector interposed with respect to the particulate filter. The engine includes an upper cover member covering an upper portion thereof
The upper cover member has a top wall disposed above the engine, and a front wall including an opening opening forward and extending downward from a front end of the top wall.
The exhaust gas purification apparatus for an engine according to any one of claims 1 to 5, wherein the sensor main body is attached to an upper portion of the engine at a rear of the opening.

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