JP2018127931A - Exhaust system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust system capable of easily cleaning a filter.SOLUTION: An exhaust system includes an exhaust passage configured to guide to the atmosphere exhaust gas occurring in an internal combustion engine mounted on a vehicle, and a filter configured to collect particulate substrate in the exhaust gas by passing the exhaust gas having been guided in the exhaust passage from an upstream side end surface to a downstream side end surface. Here, in the exhaust passage, an open hole is formed on a downstream side in an exhaust gas flow direction with respect to the downstream side end surface, and to the open hole, an openable/closable lid is attached. In opening the lid, through the open hole, the downstream side end surface faces any one of front, back, right and left directions of the vehicle.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an exhaust system including a filter that collects particulate matter in exhaust gas in an exhaust passage of an internal combustion engine.

  Conventionally, as this type of exhaust system, for example, there is an exhaust purification device described in Patent Document 1. In this exhaust purification apparatus, the DPF assembly includes a DPF fixedly housed in a case in order to collect particulate matter contained in the exhaust gas of an internal combustion engine (typically a diesel engine). . The DPF assembly includes a cleaning agent supply unit branched from the exhaust passage on the exhaust gas outflow side, and a cleaning agent discharge unit branched from the exhaust passage on the exhaust gas inflow side. When cleaning the DPF, the cleaning agent is supplied from the cleaning agent supply unit side while the DPF assembly is mounted in the exhaust passage. As a result, deposits inside the DPF (typically sulfa-based unburned components) are discharged together with the DPF cleaning agent to the cleaning agent discharge portion side which is a lower position than the DPF.

Japanese Patent Laid-Open No. 2003-3826

  In the conventional exhaust purification device, the filter is arranged in the vertical direction (that is, the direction in which the exhaust gas flows in the filter is along the vertical direction). However, the filter may be attached to the lower part of the vehicle in the lateral direction. Even in such a case, it is required that the filter can be easily cleaned.

  Therefore, an object of the present disclosure is to provide an exhaust system that can easily clean a filter.

  The present disclosure relates to an exhaust passage that guides exhaust gas generated in an internal combustion engine mounted on a vehicle to the atmosphere, and the exhaust gas that has been guided through the exhaust passage passes from an upstream end face to a downstream end face. And a filter for collecting the particulate matter. Here, in the exhaust passage, a through hole is formed on the downstream side in the flow direction of the exhaust gas from the downstream end surface, and a lid that can be opened / closed is attached to the through hole. When opened, the downstream end surface faces one of the front, rear, left and right directions of the vehicle through the through hole.

  According to the exhaust system of the present disclosure, the filter can be easily cleaned.

Schematic diagram showing the configuration of the exhaust system of the present disclosure Schematic diagram showing how the DPF (filter) is cleaned in the exhaust system of FIG.

  Hereinafter, the exhaust system of the present disclosure will be described in detail with reference to the drawings.

<1. Definition>
In each figure, an x-axis, a y-axis, and a z-axis indicate a vehicle front-rear direction, a left-right direction, and a vertical direction. The z-axis particularly indicates the direction from the bottom to the top of the vehicle.
DOC is an acronym for Diesel Oxidation Catalyst. DPF is an acronym for Diesel Particulate Filter. Moreover, SCR is Selective Catalytic Reduction. RDOC is an acronym for Rear Diesel Oxidation Catalyst.

<2. Outline structure of exhaust system>
In each figure, the exhaust system 1 is connected to an internal combustion engine 3 such as a diesel engine so as to be in fluid communication, and generally includes an exhaust passage 11 and a plurality of aftertreatment devices 13.

  The exhaust passage 11 is mainly made of metal piping, and is provided, for example, in the lower part of the vehicle. The exhaust passage 11 guides exhaust gas generated by fuel combustion in the internal combustion engine 3 to the atmosphere.

  The plurality of aftertreatment devices 13 are attached in the middle of the exhaust passage 11, perform predetermined processing on the exhaust gas guided through the exhaust passage 11, and send the exhaust passage 11 downstream in the exhaust gas flow direction. In the present disclosure, as the plurality of post-processing devices 13, DOC 13a, DPF 13b, SCR 13c, and RDOC 13d are exemplified. Generally, these are arranged in the order of DOC 13a, DPF 13b, SCR 13c, and RDOC 13d from the upstream side in the exhaust passage 11.

  The DOC 13a has, for example, a cylindrical shape and includes a honeycomb carrier made of ceramic. A number of through holes are formed in this honeycomb carrier. Each through-hole penetrates from the upstream end face facing each other in the central axis direction of the cylindrical DOC 13a to the downstream mold end face. Further, a noble metal catalyst is supported or coated on the surface of the through hole (that is, the honeycomb wall surface).

  The DOC 13a as described above is arranged so that its central axis is along the flow direction of the exhaust gas, and mainly oxidizes unburned gas in the exhaust gas guided through the exhaust passage 11.

  For example, the DPF 13b has a columnar shape and includes a honeycomb carrier made of ceramic. In the present disclosure, the DPF 13b is a so-called wall flow filter. In the wall flow type, the upstream end surface and the downstream end surface of the honeycomb carrier are alternately sealed, and such a honeycomb wall surface is used as a filtration surface. A noble metal catalyst may be supported or coated on the honeycomb wall surface.

  The DPF 13b as described above is arranged in the exhaust passage 11 immediately downstream of the DOC 13a so that its central axis is along the flow direction of the exhaust gas. In the DPF 13b, the exhaust gas guided through the exhaust passage 11 passes from the upstream end face to the downstream end face. In the process, the DPF 13b collects particulate matter in the exhaust gas on the honeycomb wall surface.

  The SCR 13c has, for example, a cylindrical shape and a honeycomb carrier made of ceramic. A catalyst such as zeolite or vanadium is supported or coated on the honeycomb wall surface.

  The SCR 13c as described above is arranged in the exhaust passage 11 on the downstream side of the DPF 13b so that its central axis is along the flow direction of the exhaust gas. Further, urea water as a reducing agent is injected between the DPF 13b and the SCR 13c in the exhaust passage 11 and supplied to the exhaust gas that has passed through the DPF 13b. As a result, urea is hydrolyzed to ammonia. While the exhaust gas containing ammonia passes through the SCR 13c, nitrogen oxide (so-called NOx) reacts with nitrogen and water by the action of the catalyst. Thereby, nitrogen oxides in the exhaust gas are purified.

  The RDOC 13d has a configuration similar to that of the DOC 13a, is disposed immediately downstream of the SCR 13c in the exhaust passage 11, and oxidizes ammonia slipped from the SCR 13c.

  The exhaust gas purified by each of the aftertreatment devices 13 as described above is released into the atmosphere from the exhaust passage 11 via a muffler or the like.

<3. Configuration for DPF cleaning>
Hereinafter, a portion of the exhaust passage 11 where the DOC 13a and the DPF 13b are provided is referred to as a first partial passage 11a. Further, a portion where the SCR 13c and the RDOC 13d are provided is referred to as a third partial passage 11c. In the exhaust passage 11, a portion between the first partial passage 11a and the third partial passage 11c is referred to as a second partial passage 11b.

  The first partial passage 11a extends along the y-axis direction. A through hole 15 is formed at the downstream end of the first partial passage 11a. The through-hole 15 preferably overlaps with the downstream end face of the DPF 11b in substantially the same shape in plan view from the y-axis direction. Further, it is more preferable that there is nothing to block between the through hole 15 and the downstream end surface, and the downstream end surface can be seen through the through hole 15. The distance in the y-axis direction from the downstream end face of the DPF 13b to the through hole 15 is more preferably as short as possible.

  A lid 17 for opening / closing the through hole 15 is attached to the downstream end of the first partial passage 11a. The outer main surface of the lid 17 faces the y-axis direction with respect to the vehicle. That is, when a mechanic or the like is positioned in the y-axis direction with reference to the lid 17, there is nothing to block between the mechanic and the lid 17 so that the mechanic can see the lid 17. .

  When closed, the lid 17 is fixed to the downstream end of the first partial passage 11a with screws, bolts or the like (not shown). At the time of cleaning the DPF 13b, a mechanic or the like removes a screw or the like and removes the lid 17, whereby the through hole 15 is opened.

  Further, at least one discharge port 19 is formed at the lower end (preferably, the lowermost end) of the first partial passage 11a. In the present disclosure, as a preferred example, at least one outlet 19 includes three outlets (ie, a first outlet, a second outlet, and a third outlet) 19a to 19c. For convenience of illustration, reference numerals “19”, “19a”, “19b”, and “19c” are shown only in FIG.

  The first discharge port 19a is formed immediately upstream of the DOC 13a in the first partial passage 11a.

  The second discharge port 19b is formed between the downstream end surface of the DOC 13a and the upstream end surface of the DPF 13b in the first partial passage 11a.

  The third outlet 19c is formed immediately downstream of the DPF 13b in the first partial passage 11a.

  A lid 111 for opening / closing the corresponding outlet 19 is attached. Each lid 111 faces the lower side of the vehicle. That is, when the mechanic or the like is positioned below the vehicle, each lid 111 can be seen. In the present disclosure, lids 111a to 111c are provided corresponding to the discharge ports 19a to 19c.

  The second partial passage 11b is preferably connected to the upper end of the downstream end of the first partial passage 11a. The second partial passage 11b extends from the most upstream end in the z-axis direction and bends, and then is connected to the upstream end of the third partial passage 11c.

<4. DPF cleaning>
An on-vehicle electronic control unit (not shown) monitors, for example, a differential pressure between the upstream side and the downstream side of the DPF 13b by a well-known method, and warns the timing of combustion removal of particulate matter based on the monitoring result. Notify the driver of the vehicle by lighting the light. In response to the operation of the driver or the like, the electronic control unit burns and removes the particulate matter deposited on the DPF 13b with high-temperature exhaust gas or the like.

  Even if the particulate matter is burned and removed as described above, sulfur-based unburned components and the like often remain in the DPF 13b. Regarding such unburned components, it is necessary to wash away the DPF 13b. In that case, a vehicle mechanic first removes the lid 17 and the lids 111a to 111c.

  Thereafter, the maintenance person or the like spouts the cleaning fluid (water, cleaning agent or air flow) from the hose or the like toward the downstream end face of the DPF 13b from the through hole 15 (in other words, in the direction opposite to the flow direction of the exhaust gas). Let As a result, unburned components and the like accumulated on the honeycomb wall surface of the DPF 13b are washed away and flow out from the upstream end face together with the cleaning fluid. The cleaning fluid that has flowed out is discharged to the outside of the exhaust system 1 through the discharge port 19b together with unburned components and the like. In some cases, the cleaning fluid is also discharged from the discharge ports 19a and 19c.

  When the cleaning of the DPF 13b is completed, the maintenance person attaches the lid 17 and the lids 111a to 111c.

<5. Action and effect of this exhaust system>
As described above, in the exhaust system 1, the first partial passage 11 a in which the DPF 13 b is disposed extends along the y-axis direction (that is, the left-right direction of the vehicle), and the downstream end faces the y-axis direction. A through hole 15 is formed. There is nothing blocking the flow of the cleaning fluid between the through hole 15 and the downstream end surface of the DPF 13 b, so that the downstream end surface can be seen through the through hole 15.

  From the above, when the lid 17 is removed and the through hole 15 is opened, the DPF 13 b faces the y-axis direction through the through hole 15. That is, when a mechanic or the like is positioned in the y-axis direction of the vehicle for DPF cleaning, there is nothing to block between the through hole 15 and the downstream end surface, so that the downstream end surface can be seen. Is easy to apply the cleaning fluid to the downstream end face of the DPF 13b. Thus, according to the present disclosure, it is possible to provide the exhaust system 1 that can be easily cleaned without removing the DPF 13b from the vehicle body.

  As described above, in the exhaust system 1, the first partial passage 11a extends along the y-axis direction, and the through hole 15 is substantially the same as the downstream end surface of the DPF 11b in plan view from the y-axis direction. Overlapping in shape. According to this configuration, when the hose or the like is inserted into the through-hole 15 and the cleaning fluid is applied to the downstream end surface, neither the hose nor the cleaning fluid interferes with other parts, It becomes easy to apply the cleaning fluid from the through hole 15 to the entire end face.

  As described above, in the exhaust system 1, the second partial passage 11b is connected to the upper end portion of the first partial passage 11a and extends in the z-axis direction. With this configuration, it becomes difficult for the cleaning fluid supplied by a maintenance person or the like to enter the third partial passage 11c.

  Further, as described above, in the exhaust system 1, the discharge port 19b is formed immediately upstream of the DPF 13b in the first partial passage 11a, and the cleaning fluid is discharged from the discharge port 19b. With this configuration, the cleaning fluid can be easily discharged outside the exhaust system 1.

<6. Addendum>
In the above description, when the lid 17 is opened, both the downstream end surface of the DPF 13b and the through hole 15 face the y-axis direction (that is, either the left or right direction of the vehicle). However, the present invention is not limited to this, and when the lid 17 is opened, the downstream end surface of the DPF 13b and the through hole 15 may face the x-axis direction (that is, either the front or rear direction of the vehicle).

  Here, the phrase “facing the x-axis direction” not only means that the downstream end surface of the DPF 13b and the through hole 15 face each other in the x axis direction, but also the downstream end surface of the DPF 13b and the through hole 15 are in the x axis direction. It also includes facing each other in a direction inclined with respect to the direction (excluding the z-axis direction). The same is true for the phrase “facing the y-axis direction”.

  In the above description, each discharge port 19 has been described as being opened / closed using the lid 17. However, the present invention is not limited to this, and each outlet 19 may be opened / closed by a solenoid valve or a motor-operated valve.

  The exhaust system according to the present disclosure can easily clean the filter and is suitable for passenger cars and commercial vehicles equipped with a diesel engine.

1 Exhaust system 11 Exhaust passage 13b DPF (filter)
15 Through hole 17 Lid 19 Discharge port 3 Internal combustion engine

Claims (4)

An exhaust passage for guiding exhaust gas generated by an internal combustion engine mounted on a vehicle to the atmosphere;
The exhaust gas guided through the exhaust passage passes from the upstream end surface to the downstream end surface, and includes a filter that collects particulate matter in the exhaust gas, and
In the exhaust passage, a through hole is formed on the downstream side in the flow direction of the exhaust gas from the downstream end surface,
A lid that can be opened / closed is attached to the through hole,
An exhaust system in which the downstream end face faces one of the front, rear, left and right directions of the vehicle through the through hole when the lid is opened.   The exhaust system according to claim 1, wherein the through hole substantially overlaps the downstream end surface in a plan view from the direction. The exhaust passage is
A first partial passage in which the filter is disposed and extends along the direction;
A second partial passage connected in fluid communication with the first partial passage so as to extend upward from an upper end portion of a downstream end portion of the first partial passage;
The exhaust system according to claim 1, wherein the through hole is formed at a downstream end of the first partial passage. The exhaust system according to claim 3, wherein at least one discharge port is formed upstream of the filter at a lower end portion of the first partial passage.

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