CN111164296A

CN111164296A - EGR device for internal combustion engine

Info

Publication number: CN111164296A
Application number: CN201880062984.2A
Authority: CN
Inventors: 仓田伊织
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 2017-09-28
Filing date: 2018-09-25
Publication date: 2020-05-15
Anticipated expiration: 2038-09-25
Also published as: JP2019065715A; CN111164296B; PH12020550126A1; JP7039911B2; WO2019065594A1

Abstract

The position of the EGR apparatus of the internal combustion engine on the downstream side of the aftertreatment member in the exhaust passage includes: a low-pressure EGR passage connected to the exhaust passage in communication therewith; and a filter member that is provided at an inlet portion of the low-pressure EGR passage into which exhaust gas flows from the exhaust passage, and that protrudes into the exhaust passage. The front end of the filter member in the protruding direction is formed in a sharp dot shape or a line shape.

Description

EGR device for internal combustion engine

Technical Field

The present disclosure relates to an EGR (Exhaust Gas Recirculation) device for an internal combustion engine, and more particularly, to an EGR device that can perform low-pressure EGR.

Background

As an internal combustion engine for a vehicle, there is known an internal combustion engine including an EGR device for recirculating a part of exhaust gas to an intake side for the purpose of reducing NOx (nitrogen oxide). This EGR device is generally called a high pressure EGR device (hp (high pressure) -EGR device) which takes out a part of exhaust gas having a relatively high temperature and high pressure (referred to as "EGR gas") from an upstream side of an impeller of a turbocharger and returns the EGR gas to a downstream side of a compressor of the turbocharger. In contrast, in recent years, a low pressure EGR device (lp (lowpressure) -EGR device) may be additionally provided for the purpose of further reducing NOx. The low pressure EGR apparatus takes out relatively low temperature and low pressure EGR gas from the downstream side of the impeller of the turbocharger, and returns the EGR gas to the upstream side of the compressor of the turbocharger.

In the low-pressure EGR apparatus, a low-pressure EGR passage through which EGR gas flows is connected to a position on a downstream side of the aftertreatment member in the exhaust passage. Here, the aftertreatment member is a member that performs exhaust aftertreatment, and refers to a catalyst or a filter that removes a specific component in exhaust gas. Foreign matter generated by a defect or the like of the aftertreatment member is mixed into the exhaust gas on the downstream side of the aftertreatment member, and the mixture is introduced into the low-pressure EGR passage and reaches the intake side, whereby the compressor is damaged. Therefore, a filter member for trapping foreign matter is provided in the low-pressure EGR passage (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-202265

Disclosure of Invention

Problems to be solved by the invention

The filter member for trapping foreign matter described above is preferably provided at the inlet portion of the low-pressure EGR passage so as to protrude into the exhaust passage. This is because, by doing so, foreign matter trapped by the filter member can be detached from the filter member by the flow or force of the exhaust gas in the exhaust passage and discharged to the downstream side of the filter member, thereby causing the filter member to produce a self-cleaning action.

However, the structure and shape of the filter member actually manufactured are not necessarily optimized from the viewpoint of such a self-cleaning effect. For example, in fig. 4, 5, and 6 (a) of patent document 1, a filter member having a truncated cone shape is disclosed, but in the case of the truncated cone shape, it is difficult to remove foreign matter captured by a flat top surface or a front end surface thereof with exhaust gas. Further, fig. 6 (b) of patent document 1 discloses a dome-shaped filter member, but even in the dome shape, it is difficult to detach foreign matter captured by the curved top surface or the front end surface thereof with exhaust gas.

An object of the present disclosure is to provide an EGR device for an internal combustion engine capable of maximizing a self-cleaning effect of a filter member.

Means for solving the problems

According to an aspect of the present disclosure, there is provided an EGR apparatus of an internal combustion engine, the EGR apparatus including:

a low-pressure EGR passage that is communicatively connected to the exhaust passage at a position on a downstream side of the aftertreatment member in the exhaust passage, an

A filter member that is provided at an inlet portion of the low-pressure EGR passage into which exhaust gas flows from the exhaust passage, and that protrudes into the exhaust passage;

the filter member has a pointed or linear front end in the protruding direction.

Preferably, the filter member has a conical shape having a central axis extending in the protruding direction, and the distal end portion of the filter member is formed in a sharp point shape by a vertex of the conical shape.

Preferably, the filter member has a front surface portion inclined to the exhaust downstream side with respect to the projecting direction, and the front end portion of the filter member is formed in a sharp linear shape by an upper edge portion of the front surface portion.

The aftertreatment member may be a filter that collects particulate matter contained in the exhaust gas.

Effects of the invention

According to the present disclosure, an EGR device for an internal combustion engine that can exhibit the self-cleaning function of a filter member to the maximum can be provided.

Brief description of the drawings

Fig. 1 is a schematic diagram showing the configuration of an internal combustion engine.

Fig. 2A is a plan view of the filter member of embodiment 1.

Fig. 2B is a side sectional view of the filter member of embodiment 1.

Fig. 2C is a side perspective view of the filter member of embodiment 1.

Fig. 3A is a side cross-sectional view showing a state where foreign matter is trapped by the filter member of the comparative example.

Fig. 3B is a side sectional view showing a state where foreign matter is trapped by the filter member of embodiment 1.

Fig. 4A is a plan view of the filter member of embodiment 2.

Fig. 4B is a side sectional view of the filter member of embodiment 2.

Fig. 4C is a side perspective view of the filter member of embodiment 2.

Fig. 5A is a plan view of the filter member of embodiment 3.

Fig. 5B is a side sectional view of the filter member of embodiment 3.

Fig. 5C is a side perspective view of the filter member of embodiment 3.

Fig. 6A is a top view of the filter member of embodiment 4.

Fig. 6B is a side sectional view of the filter member of embodiment 4.

Fig. 6C is a side perspective view of the filter member of embodiment 4.

Detailed Description

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. However, it should be noted that the present disclosure is not limited to the following embodiments.

Fig. 1 shows an internal combustion engine to which an EGR apparatus according to an embodiment is applied. The internal combustion engine (also referred to as an engine) 1 is a multi-cylinder engine mounted on a vehicle (not shown). In the present embodiment, the vehicle is a large vehicle such as a truck, and the engine 1 as a vehicle power source mounted thereon is an inline 4-cylinder diesel engine. However, the type, form, use, and the like of the vehicle and the internal combustion engine are not particularly limited, and for example, the vehicle may be a small vehicle such as a passenger car, and the engine 1 may be a gasoline engine.

The engine 1 includes: an engine body 2; an intake passage 3 and an exhaust passage 4 connected to the engine body 2; a turbocharger 14; and a fuel injection device 5. The engine body 2 includes structural members such as a cylinder head, a cylinder block, and a crankcase, and movable members such as a piston, a crankshaft, and a valve, which are housed therein.

The fuel injection device 5 is constituted by a common rail (common rail) type fuel injection device, and includes: an injector 7 as a fuel injection valve provided in each cylinder; and a common rail 8 connected to the injector 7. The injector 7 is an in-cylinder injector that directly injects fuel into the cylinder 9, i.e., a combustion chamber. The common rail 8 stores the fuel injected from the injectors 7 in a high-pressure state.

The intake passage 3 is mainly defined by an intake manifold 10, which intake manifold 10 is connected to the engine body 2 (particularly, the cylinder head), and an intake pipe 11, which intake pipe 11 is connected to the upstream end of the intake manifold 10. The intake manifold 10 distributes and supplies intake air sent from an intake pipe 11 to intake ports of the respective cylinders. An air cleaner 12, an air flow meter 13, a compressor 14C of a turbocharger 14, an intercooler 15, and an electronically controlled intake throttle valve 16 are provided in this order from the upstream side in the intake pipe 11. The airflow meter 13 is a sensor for detecting an intake air flow rate, which is an intake air amount per unit time of the engine 1, and is also referred to as a Mass Air Flow (MAF) sensor or the like.

The exhaust passage 4 is mainly defined by an exhaust manifold 20 connected to the engine body 2 (particularly, a cylinder head), and an exhaust pipe 21 connected to a downstream side of the exhaust manifold 20. The exhaust manifold 20 concentrates exhaust gas sent from the exhaust port of each cylinder. An impeller 14T of the turbocharger 14 is provided on the exhaust pipe 21 or between the exhaust manifold 20 and the exhaust pipe 21. An oxidation catalyst 22, a filter 23, a selective reduction type NOx catalyst (SCR)24, and an ammonia oxidation catalyst 26 are provided in this order from the upstream side in the exhaust passage 4 on the downstream side of the impeller 14T. They constitute an aftertreatment component that performs exhaust aftertreatment. A urea injector 25 as a reducing agent injection valve is provided in the exhaust passage 4 between the filter 23 and the NOx catalyst 24, and the urea injector 25 injects urea water as a reducing agent into the exhaust passage 4.

The oxidation catalyst 22 oxidizes and purifies unburned components (hydrocarbons HC and carbon monoxide CO) in the exhaust gas, and heats the exhaust gas with the reaction heat at that time. The filter 23 is a so-called continuous regeneration type diesel particulate filter, and collects particulate matter (also referred to as PM) contained in the exhaust gas, and continuously burns and removes the collected PM by reacting the collected PM with a precious metal. As the filter 23, a so-called wall-flow type filter in which both end openings of a ceramic substrate having a honeycomb structure are alternately blocked in a lattice manner is used.

The NOx catalyst 24 reduces and purifies NOx by reacting ammonia obtained by hydrolyzing the urea aqueous solution injected from the urea injector 25 with NOx in the exhaust gas. Examples of the NOx catalyst 24 include a catalyst in which a noble metal such as Pt is supported on the surface of a base material such as zeolite or alumina, a catalyst in which a transition metal such as Cu is ion-exchanged on the surface of the base material to support the metal, and a titania-vanadium catalyst (V) supported on the surface of the base material₂O₅/WO₃/TiO₂) And the like. The ammonia oxidation catalyst 26 oxidizes and purifies the excess ammonia discharged from the NOx catalyst 24.

The engine 1 includes an electronically controlled exhaust throttle valve 37 and an exhaust injector 38, which are provided in the exhaust passage 4, respectively. In the present embodiment, these are provided in the exhaust passage 4 between the impeller 14T and the oxidation catalyst 22, and an exhaust injector 38 is disposed downstream of the exhaust throttle valve 37. However, the positions where they are installed may be changed. The exhaust throttle valve 37 is a valve for regulating the flow rate of exhaust gas. The exhaust injector 38 is mainly an injector for injecting fuel into the exhaust passage 4 when the filter 23 is regenerated.

Further, the engine 1 includes an EGR device. The EGR apparatus of the present embodiment includes a high-pressure EGR apparatus 30 and a low-pressure EGR apparatus 40.

The high-pressure EGR device 30 takes out EGR gas, which is a part of relatively high-temperature and high-pressure exhaust gas, from the upstream side of the impeller 14T of the turbocharger 14, and returns the EGR gas to the downstream side of the compressor 14C of the turbocharger 14.

The high-pressure EGR device 30 includes: a high-pressure EGR passage 31 having an inlet end 31A connected in communication with the exhaust passage 4 and an outlet end 31B connected in communication with the intake passage 3; a high-pressure EGR cooler 32 that cools the EGR gas flowing in the high-pressure EGR passage 31; and a high-pressure EGR valve 33 for adjusting the flow rate of EGR gas flowing in the high-pressure EGR passage 31. In the present embodiment, the inlet end 31A of the high-pressure EGR passage 31 is connected to the exhaust manifold 20, and the outlet end 31B of the high-pressure EGR passage 31 is connected to the intake manifold 10. The high-pressure EGR passage 31 is defined by a high-pressure EGR pipe 31P extending outside the engine body 2.

The low-pressure EGR device 40 takes out relatively low-temperature and low-pressure EGR gas from the downstream side of the impeller 14T of the turbocharger 14, and returns the EGR gas to the upstream side of the compressor 14C of the turbocharger 14.

The low-pressure EGR apparatus 40 includes: a low-pressure EGR passage 41 having an inlet end 41a connected in communication with the exhaust passage 4 and an outlet end 41b connected in communication with the intake passage 3; a low-pressure EGR cooler 42 that cools EGR gas flowing in the low-pressure EGR passage 41; and a low-pressure EGR valve 43 for adjusting the flow rate of EGR gas flowing in the low-pressure EGR passage 41.

In the present embodiment, the inlet end 41a of the low-pressure EGR passage 41 is connected to the exhaust passage 4 at a position downstream of the filter 23 and upstream of the NOx catalyst 24 and the urea injector 25. The outlet end 41b of the low-pressure EGR passage 41 is connected to the intake passage 3 at a position on the upstream side of the compressor 14C and on the downstream side of the airflow meter 13. The low-pressure EGR passage 41 is defined by a low-pressure EGR pipe 41P.

The control device for controlling the engine 1 has an electronic control unit (referred to as ECU)100 constituting a control unit, a circuit element (circuit) or a controller. The ECU100 includes a CPU, ROM, RAM, input/output ports, storage devices, and the like. The ECU100 is configured to control the in-cylinder injector 7, the intake throttle valve 16, the urea injector 25, the exhaust throttle valve 37, the exhaust injector 38, the high-pressure EGR valve 33, and the low-pressure EGR valve 43, and is programmed.

The control device includes, as sensors: the above-mentioned airflow meter 13; a rotation speed sensor 51 for detecting a rotation speed of the engine (specifically, a rotation speed per minute (rpm)); and an accelerator opening sensor 52 for detecting an accelerator opening. Output signals of these sensors are sent to the ECU 100.

In addition, in the present embodiment, there is a risk that: foreign matter generated by a defect of the filter 23 or the like is mixed into the exhaust gas in the exhaust passage 4 on the downstream side of the filter 23, and is introduced into the low-pressure EGR passage 41 to reach the intake side, whereby the compressor 14C is damaged.

More specifically, a part of the ceramic substrate constituting the filter 23 is broken to become a solid foreign substance. Other examples of foreign matter are also considered, such as sputtering in exhaust pipe 21. When such foreign matter passes through the low-pressure EGR passage 41 and the intake passage 3 and reaches the compressor 14C, the foreign matter may strike the fins of the compressor 14C, and the fins may be damaged.

Therefore, in the present embodiment, the filter member 60 for trapping foreign matter is provided to the low-pressure EGR passage 41, so that the following is prevented or suppressed: foreign matter in the exhaust passage 4 intrudes into the low-pressure EGR passage 41, and reaches the intake passage 3 or the compressor 14C. This can prevent or suppress damage to the compressor 14C due to foreign matter.

In particular, in the present embodiment, the filter member 60 is provided at the inlet portion of the low-pressure EGR passage 41 into which exhaust gas flows from the exhaust passage 4 so as to protrude into the exhaust passage 4. Thus, the foreign matter trapped by the filter member 60 can be detached from the filter member 60 by the flow and force of the exhaust gas in the exhaust passage 4, and can be discharged to the exhaust passage 4 on the downstream side of the filter member 60, and the filter member 60 can be caused to perform a self-cleaning action.

The filter member 60 of the present embodiment is optimized in structure and shape so as to exhibit the self-cleaning function to the maximum extent. Hereinafter, preferred examples of the filter member 60 of the present embodiment will be described.

[ 1 st embodiment ]

Fig. 2A to 2C show example 1 of a filter member 60 according to the present embodiment. Fig. 2A is a plan view, fig. 2B is a side sectional view, and fig. 2C is a side perspective view. The flow of the exhaust gas is denoted by G, and the central axis of the exhaust passage 4 is denoted by C1. Unless otherwise specified, the axial direction, the radial direction, and the circumferential direction with respect to the central axis C1 are simply referred to as the axial direction, the radial direction, and the circumferential direction, respectively.

In particular, in fig. 2B, the configuration of the connection portion of the exhaust passage 4 and the low-pressure EGR passage 41 is shown. On the exhaust pipe 21 defining the exhaust passage 4, a thick-walled boss portion 27 and an insertion hole 28 are provided for connecting a low-pressure EGR pipe 41P defining a low-pressure EGR passage 41 in a crossing (orthogonal) state. The inlet end of the low-pressure EGR pipe 41P is inserted into the insertion hole 28, and the flange 29 formed around the insertion hole is attached to the boss 27 with bolts or the like, not shown, so as to be fixed to the exhaust pipe 21. In the case of the present embodiment, the low-pressure EGR passage 41 (low-pressure EGR pipe 41P) is connected to the bottom of the exhaust passage 4 (exhaust pipe 21).

The filter member 60 is fastened and fixed so as to be sandwiched between the exhaust pipe 21 and the low-pressure EGR pipe 41P. That is, the filter member 60 has, at its base end portion: an annular base portion 61 sandwiched and fastened together between the boss portion 27 and the flange portion 29; and a cylindrical portion 62 that extends from an inner peripheral edge of the base portion 61 into the exhaust pipe 21 and passes through a gap between the low-pressure EGR pipe 41P and the insertion hole 28. In this way, filter member 60 is fixed to exhaust pipe 21 at its base end portion, and is positioned so that a portion on the tip end side of the base end portion is exposed into exhaust pipe 21.

The method of mounting the exhaust pipe 21, the low-pressure EGR pipe 41P, and the filter member 60 is not limited to this, and any other method may be employed. For example, the low-pressure EGR pipe 41P and the filter member 60 may be attached to the exhaust pipe 21.

As shown in fig. 2B, in the three mounted states, the inlet end surface 41A of the low-pressure EGR pipe 41P is positioned substantially flush with the inner peripheral surface 21A of the exhaust pipe 21. The inlet portion 41B of the low-pressure EGR pipe 41P is directed radially toward the central axis C1 of the exhaust passage 4 (see fig. 2A).

Along the same radial direction, filter member 60 protrudes into exhaust pipe 21 from the radially outer side (lower side in fig. 2B) to the radially inner side (upper side in fig. 2B) in exhaust pipe 21. In the present embodiment, as shown in the drawing, filter member 60 protrudes upward into exhaust pipe 21 from below in the vertical direction. The filter member 60 covers the entire inlet portion 41B.

As for the filter member 60, the entirety thereof is formed of a wire mesh, for example, a wire mesh made of stainless steel. However, the filter member 60 may be formed of other materials, for example, a perforated metal plate, as long as the purpose of capturing foreign matter is achieved. Alternatively, the wire mesh may be stretched over the metal frame. However, since it is advantageous in terms of cost when formed of a single material, the configuration of the present embodiment formed only of the wire mesh is advantageous in terms of cost.

In the present embodiment, the front end 63 of the filter member 60 in the protruding direction is formed in a sharp point shape. Specifically, the filter member 60 has a conical shape having a central axis C2 extending in the protruding direction, and the distal end portion 63 of the filter member 60 is formed in a sharp point shape with a vertex P of the conical shape. In the case of the present embodiment, the cone is set to be a cone. The outer diameter D1 of the portion of the filter member 60 located inside the exhaust pipe 21 (the outer diameter of the bottom surface of the cone) is larger than the inner diameter D2 of the inlet portion 41B of the low-pressure EGR pipe 41P. Therefore, the inlet portion 41B is completely covered with the filter member 60, and intrusion of foreign matter into the low-pressure EGR pipe 41P is reliably prevented or suppressed.

The wall surface of the filter member 60 around the center axis C2 is formed as a circumferentially inclined surface, and there is no wall surface of the filter member 60 parallel or substantially parallel to the flow direction of the exhaust gas G, that is, the axial direction of the exhaust passage 4 (the direction of the center axis C1). In other words, the wall surface of the filter member 60 is set to be not parallel to the axial direction at any position.

In the present embodiment, the center axis C2 is the center axis of the filter member 60 and the cone, and is also the center axis of the inlet portion 41B of the low pressure EGR pipe 41P. Therefore, the filter member 60 and the inlet portion 41B are arranged coaxially with each other. Further, the center axis C2 is along the radial direction of the exhaust passage 4. Therefore, the projecting direction may be a direction directed from the radially outer side of the exhaust passage 4 to the inner side.

Next, the operation and effect of the present embodiment will be described.

In fig. 3A, a case is shown when the foreign matter X is captured by the filter member 60' of the comparative example different from the present embodiment. The filter member 60' of this comparative example is the same as the filter member 60 of the present embodiment in that it projects into the exhaust passage 4, but is different from the filter member 60 of the present embodiment in that it has a wall surface parallel to the flow direction of the exhaust gas G, i.e., the axial direction.

Fig. 3A shows a case where the foreign matter X is captured and sandwiched between a pair of wires constituting the wire mesh which are parallel wall surfaces in the axial direction, that is, the upstream side wire 81 and the downstream side wire 82. In this case, a portion of the foreign matter X located on the lower side than the upper ends of the

wire rods

81, 82, that is, a portion X1 where the foreign matter X passes through the upper ends of the

wire rods

81, 82 and is located on the lower side than the line a parallel to the axial direction is hidden on the back surface of the wire rod 81 on the upstream side with respect to the flow of the exhaust gas G. Therefore, the exhaust gas G does not hit the portion X1, and the area of the foreign matter X that is touched by the exhaust gas G as a whole is reduced, and as a result, the exhaust gas G hardly hits the foreign matter X. Therefore, the self-cleaning action of removing or separating the foreign matter X held by the exhaust gas G by the flow or force thereof is weakened.

In contrast, in fig. 3B, the case when the foreign matter X is captured by the filter member 60 of the present embodiment is shown. The filter member 60 of the present embodiment has an inclined front surface portion 72A (see fig. 2A to 2C) facing the flow of the exhaust gas G. Fig. 3B shows a case where a foreign object X is interposed between a pair of wires of the wire mesh constituting the wall surface of the front surface portion 72A, that is, an upper wire 83 and a lower wire 84. The upper wire 83 is located slightly downstream or rearward of the lower wire 84 with respect to the flow of the exhaust gas G.

In this case, the portion hidden on the back surface of the wire rod with respect to the flow of the exhaust gas G is only the small portion X2 of the foreign matter X passing through the upper end of the wire rod 84 below and located below the line b parallel to the axial direction. Therefore, the exhaust gas G collides with almost all the area of the foreign matter X, and as a result, the exhaust gas G easily collides with the foreign matter X. Therefore, the self-cleaning action of removing or separating the foreign matter X from the exhaust gas G can be sufficiently and effectively obtained by the flow or force of the exhaust gas G.

The detached foreign matter X bypasses the periphery of the filter member 60, for example, by riding on the flow of the exhaust gas G, and is discharged to the downstream side of the filter member 60.

The actual flow of the exhaust gas G includes not only a flow parallel to the axial direction as a main flow but also a turbulent flow, i.e., a flow not parallel to the axial direction. In the present embodiment, the turbulent flow is also caused to positively collide with the foreign matter X, and the foreign matter X interposed between the

wires

83, 84 can be positively peeled off and removed.

In this manner, in the present embodiment, the front end 63 of the filter member 60 in the protruding direction is formed in a sharp point shape. Therefore, the structure and shape of the filter member 60 can be optimized from the viewpoint of the self-cleaning function, and the self-cleaning function of the filter member 60 can be exhibited to the maximum extent.

Particularly in the present embodiment, the filter member 60 has a conical shape having a central axis C2 extending in the protruding direction, and the front end portion 63 of the filter member 60 is formed in a sharp point shape by the apex P of the conical shape. Therefore, it is not necessary to provide a wall surface parallel or substantially parallel to the flow direction of the exhaust gas G in the filter member 60, and it is possible to reliably suppress the foreign matter X sandwiched therebetween from being difficult to detach and the self-cleaning function from becoming weak. In other words, by making all the wall surfaces of the filter member 60 non-parallel to the flow direction of the exhaust gas G, the exhaust gas G is made to easily touch foreign matter trapped by the wall surfaces, and the self-cleaning action can be improved.

In the case of the filter member having a truncated cone shape as shown in fig. 4, 5, and 6 (a) of patent document 1, the flat top surface or the front end surface thereof is parallel or substantially parallel to the flow direction of the exhaust gas. Therefore, the exhaust gas hardly touches the foreign matter caught by the top surface, and the foreign matter is hardly detached. Further, even in the case of the dome-shaped filter member shown in fig. 6 (b) of patent document 1, the curved top surface or the front end surface is parallel or substantially parallel to the flow direction of the exhaust gas. Therefore, since the exhaust gas hardly touches the foreign matter captured by the top surface, it is difficult to detach the foreign matter. Therefore, the self-cleaning action of the present embodiment cannot be expected in these techniques. In addition, although the water absorbing material is attached to the top surface of the filter member of patent document 1, it is considered appropriate to omit the water absorbing material when compared with the present embodiment.

[ example 2 ]

Next, example 2 of the filter member 60 of the present embodiment will be described with reference to fig. 4A to 4C. Note that, the same portions as those in embodiment 1 are denoted by the same reference numerals in the drawings, and the description thereof is omitted, and the differences from embodiment 1 are mainly described below (the same applies to the embodiments described below).

The filter member 60 of the present embodiment also has a sharp pointed front end 63 and has a conical shape. However, in the case of the present embodiment, the cone is provided as a rectangular pyramid, in particular, a regular rectangular pyramid. The filter member 60 includes a front surface portion 73A, a rear surface portion 73B, and left and right

side surface portions

73C and 73D, which are inclined with respect to the central axis C2. In the present embodiment, the front surface portion 73A and the rear surface portion 73B are perpendicular to the axial direction C1, and the

side surface portions

73C and 73D are parallel to the axial direction C1 in a plan view as shown in fig. 4A. However, it is also possible to rotate it around the central axis C2, thereby changing their orientation.

Even when the filter member 60 is formed in a different tapered shape in this manner, the same operational effects as those of embodiment 1 can be exhibited.

Although not shown, the filter member 60 may have another conical shape, for example, another pyramid shape such as a triangular pyramid, a hexagonal pyramid, or an octagonal pyramid, or an elliptical cone shape having an elliptical bottom surface.

[ example 3 ]

Next, example 3 of the filter member 60 of the present embodiment will be described with reference to fig. 5A to 5C.

In the present embodiment, the front end 63 of the filter member 60 in the protruding direction is formed in a sharp linear shape. Specifically, the filter member 60 has a front surface portion 74A inclined toward the exhaust downstream side with respect to the protruding direction, and the front end portion 63 of the filter member 60 is formed in a sharp linear shape by the upper edge portion E of the front surface portion 74A. The tip end 63 extends in a direction perpendicular to the central axes C1 and C2.

More specifically, the filter member 60 is generally shaped like a triangular roof as a whole. The filter member 60 has a flat front surface portion 74A, a rear surface portion 74B, and left and right

side surface portions

74C, 74D, which are located in the exhaust pipe 21. The front surface portion 74A and the rear surface portion 74B are formed in a quadrilateral shape, and the left and right

side surface portions

74C, 74D are formed in a triangular shape (particularly, a right-angled triangle).

The front surface portion 74A is located on the exhaust upstream side of the rear surface portion 74B, and faces the flow of the exhaust gas G. As shown in fig. 5A, the front surface portion 74A and the rear surface portion 74B are perpendicular to the axial direction C1, and the

side surface portions

73C and 73D are parallel to the axial direction C1.

The front face portions 74A are inclined at an angle α (°) to the exhaust downstream side with respect to the projecting direction (center axis C2), and are also inclined at an angle β (90- α) with respect to the flow direction, i.e., the axial direction, of the exhaust gas G the front face portions 74A gradually go to the radially inner side as they go to the exhaust downstream side, the height thereof becoming higher.

The operation and effect of this embodiment are also the same as those of embodiment 1. Since there is no wall surface parallel or substantially parallel to the axial direction, it is possible to solve the problem that foreign matter captured by the wall surface is difficult to detach and the self-cleaning action is weakened.

That is, in the present embodiment, the front end 63 of the filter member 60 in the protruding direction is formed in a sharp linear shape. Therefore, from the viewpoint of the self-cleaning function, the structure and shape of the filter member 60 can be optimized, and the self-cleaning function of the filter member 60 can be exhibited to the maximum.

In particular, in the present embodiment, the filter member 60 has the front face portion 74A inclined toward the exhaust downstream side with respect to the projecting direction, and the front end portion 63 of the filter member 60 is formed in a sharp linear shape by the upper edge portion E of the front face portion 74A. Therefore, as described with reference to fig. 3B, the exhaust gas G can be made to contact a large area of the foreign matter X sandwiched between the wires of the front surface portion 74A, so that the exhaust gas G can easily contact the foreign matter X, and the sandwiched foreign matter X can be easily detached by the flow and force of the exhaust gas G, thereby improving the self-cleaning action.

[ 4 th example ]

Next, example 4 of the filter member 60 of the present embodiment will be described with reference to fig. 6A to 6C.

The filter member 60 of the present embodiment also has a sharp linear front end portion 63, and is shaped like a triangular roof substantially as a whole. However, the left and right

side surface portions

74C, 74D are formed in an isosceles triangle shape, and the rear surface portion 74B is also inclined.

In detail, the front face portions 74A are inclined toward the exhaust downstream side at an angle α 1 (<) with respect to the projecting direction (the center axis C2), as in embodiment 3, whereas the rear face portions 74B are inclined toward the exhaust upstream side at an angle α 2 (<) with respect to the projecting direction, the rear face portions 74B gradually go to the radially outer side as they go toward the exhaust downstream side, and the height thereof becomes lower, the front face portions 74A are inclined at an angle β 1-90- α 1 (<) with respect to the flow direction, i.e., the axial direction, of the exhaust gas G, and the rear face portions 74B are inclined toward the opposite direction at an angle β 2-90- α 2 (<) with respect to the axial direction, i.e., the flow direction, of the exhaust gas.

In the present embodiment, α 1 is equal to α 2, and the tip end 63 is on the central axis C2, however, the present invention is not limited to this, α 1 and α 2 may be different, and the tip end 63 may be offset from the central axis C2, that is, the left and right

side surface portions

74C and 74D may be triangular shapes other than isosceles triangles, and the left and right

side surface portions

74C and 74D may be triangular shapes different from isosceles triangles.

Even when the filter member 60 is formed in a different shape in this way, the same operational effects as those of embodiment 3 can be exhibited.

Although not shown, the shape, structure, or arrangement of the filter member 60 of

embodiments

3 and 4 can be further changed. For example, it may also be configured such that: the filter member 60 is rotated at an arbitrary angle about the center axis C2. The distal end 63 may be curved instead of linear as shown in fig. 5C and 6C.

While the embodiments of the present disclosure have been described in detail above, the present disclosure can have other various embodiments.

(1) For example, the aftertreatment member in the exhaust passage may not be the filter 23 for trapping PM, but may be another aftertreatment member (for example, the oxidation catalyst 22, the NOx catalyst 24, or the ammonia oxidation catalyst 26). This is because, even if the post-treatment member is a member other than the filter 23, there is a risk that the post-treatment member is broken or mixed with foreign matter.

(2) In the case of the filter member 60 having the sharp linear front end 63 (for example, in embodiments 3 and 4), the bottom surface may not be a square shape, but may be any shape, for example, a polygon other than a square shape, a circle, an ellipse, or the like.

The configurations of the foregoing embodiments can be combined partially or entirely without contradiction. The embodiments of the present disclosure are not limited to the embodiments described above, and all modifications, application examples, and equivalents included in the idea of the present disclosure defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be construed restrictively, and can also be applied to any other techniques within the scope of the idea of the present disclosure.

The present application is based on japanese patent application filed on 28/9/2017 (japanese patent application 2017-188586) and the content thereof is hereby incorporated by reference.

Industrial applicability

The EGR device of the present disclosure is useful in that the self-cleaning action of the filter member is exhibited to the maximum.

Description of the reference numerals

1 internal combustion engine (Engine)

4 exhaust channel

23 Filter

41 low pressure EGR passage

41B inlet part

60 Filter element

63 front end portion

Claims

1. An EGR apparatus of an internal combustion engine, comprising:

2. The EGR device of an internal combustion engine according to claim 1,

the filter member has a conical shape having a central axis extending in the protruding direction, and the distal end portion of the filter member is formed in a sharp point shape from a vertex of the conical shape.

3. The EGR device of an internal combustion engine according to claim 1,

the filter member has a front surface portion inclined toward an exhaust downstream side with respect to the projecting direction, and the front end portion of the filter member is formed in a sharp linear shape by an upper end edge portion of the front surface portion.

4. An EGR device for an internal combustion engine according to any one of claims 1 to 3, wherein,

the aftertreatment member is a filter that traps particulate matter contained in the exhaust gas.