WO2011004747A1 - Pm sensor - Google Patents
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- WO2011004747A1 WO2011004747A1 PCT/JP2010/061146 JP2010061146W WO2011004747A1 WO 2011004747 A1 WO2011004747 A1 WO 2011004747A1 JP 2010061146 W JP2010061146 W JP 2010061146W WO 2011004747 A1 WO2011004747 A1 WO 2011004747A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0084—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours provided with safety means
- B01D46/0086—Filter condition indicators
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
- B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
- B01D46/2418—Honeycomb filters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate sensor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
- F01N3/0222—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
Definitions
- the present invention relates to a PM sensor that can accurately detect the amount of PM accumulated in a DPF with a simple configuration.
- a diesel particulate filter (hereinafter referred to as DPF) is installed in the exhaust gas exhaust passage from the internal combustion engine to the atmosphere, and the SOF contained in the exhaust gas, Particulate matter (Matter) such as SOOT is collected (hereinafter collectively referred to as PM).
- the DPF is a member that temporarily collects PM in a filter having a honeycomb pore shape (including a square one) mainly made of ceramic.
- DPF regeneration When PM collected in DPF accumulates, exhaust pressure rises and engine characteristics deteriorate, so the accumulated PM is combusted. This operation is called DPF regeneration. During DPF regeneration, the exhaust temperature is raised by fuel injection for raising the exhaust temperature, and the DPF is combusted by raising the temperature of the DPF.
- DPF regeneration is performed every time the travel distance of the vehicle reaches a predetermined value because it is difficult to detect the amount of PM accumulated in the DPF (PM load; indicating the degree of filter clogging).
- PM load indicating the degree of filter clogging
- the amount of PM is detected from the pressure difference between exhaust gas upstream and downstream of the DPF.
- the flow rate / temperature of the exhaust gas is constantly changing with the state change of the internal combustion engine, the amount of PM detected from the pressure difference is not accurate.
- Patent Document 1 for the purpose of detecting the amount of PM, an air-fuel ratio change which is not necessary for vehicle travel is given, which is not preferable.
- an object of the present invention is to provide a PM sensor that can solve the above-described problems and can accurately detect the amount of PM accumulated in the DPF with a simple configuration.
- the present invention provides a diesel particulate filter (DPF) having a porous filter body partitioned by a number of partition walls, and forms two capacitors facing each other on the upstream side and the downstream side.
- An electrode is installed, and the amount of PM collected in the DPF is detected from the capacitance of the capacitor.
- One of the two electrodes may be provided upstream of the filter body, and the other electrode may be provided downstream of the filter body.
- the above two electrodes may each be formed in a mesh shape.
- FIG. 1A is a block diagram of a PM sensor according to an embodiment of the present invention.
- FIG. 1A illustrates a case where the amount of PM is small
- FIG. 1B illustrates a case where the amount of PM is large.
- FIG. 2A is a model (equivalent circuit) diagram of the PM sensor in FIG. 1,
- FIG. 2A shows a time when the amount of PM is small
- FIG. 2B shows a time when the amount of PM is large.
- It is a graph of the rate of change of the amount of PM versus capacitance in the PM sensor of the present invention.
- It is a perspective view of PM sensor which shows one embodiment of the present invention.
- a PM sensor 1 As shown in FIG. 1 (a), a PM sensor 1 according to the present invention is provided upstream of a diesel particulate filter (DPF) 3 having a porous filter body 2 partitioned by a number of ceramic partition walls. And two electrodes 4a and 4b that form a capacitor opposite to each other on the downstream side, and the amount of PM collected in the DPF 3 is detected from the capacitance of the capacitor.
- DPF diesel particulate filter
- a detection unit for detecting the capacitance of the capacitor formed by the electrodes 4a and 4b and a calculation unit for converting the capacitance to the amount of PM are provided inside the electronic control unit (ECU) 5. It shall be.
- the PM sensor 1 shown in FIG. 1A is modeled as shown in FIG. That is, the capacitance detection unit 22 is connected to a capacitor 21 in which two flat electrodes having the same size are opposed to each other with a predetermined distance between the electrodes.
- FIG. 1B shows that the amount of PM is large by making the hatching of the DPF 3 darker than that in FIG.
- PM model of the sensor 1 the value the capacitance of the capacitor 21 is large as shown in FIG. 2 (b) from the state is a value C 0 low capacitance of the capacitor 21 as shown in FIG. 2 (a) changes to the state is a C 1 (C 1> C 0 ).
- Detecting unit 22 detects the capacitance of capacitor 21. At this time, if the capacitance is C, the dielectric constant of the medium between the electrodes is ⁇ , the area of the electrodes is S, and the distance between the electrodes is d,
- the capacitance C increases as the dielectric constant ⁇ increases or the inter-electrode distance d decreases.
- the present inventors investigated through experiments how the capacitance C of the capacitor formed by the two electrodes 4a and 4b installed in the PM sensor 1 changes depending on the amount of collected PM. It was. That is, by sucking from the downstream of the PM sensor 1, air was flown from the upstream to the downstream, and PM was gradually added into the air upstream of the PM sensor 1, and the change in the capacitance C was recorded. As a result, as shown in FIG. 3, it was found that the capacitance C increased almost linearly with respect to the amount of PM input. That is, the capacitance C accurately indicates the amount of PM collected by the PM sensor 1.
- the reason why the capacitance C increases in proportion to the amount of collected PM is that the conductor carbon is inserted between the electrodes 4a and 4b, so that the inter-electrode distance d is apparently reduced and the capacitance is increased. It is conceivable that C increases or PM increases in the medium between the electrodes 4a and 4b and the dielectric constant ⁇ increases and the capacitance C increases.
- the amount of PM collected can be accurately detected. Since the PM sensor 1 of the present invention has a simple configuration in which only the electrodes 4a and 4b are arranged, there are advantages that manufacturing is easy and cost is low.
- the PM sensor 1 is collected between the electrodes 4a and 4b, regardless of where the two electrodes 4a and 4b on the upstream side and the downstream side are installed in the longitudinal direction of the filter body 2 due to the operation principle described above.
- the amount of PM is detected from the capacitance.
- one electrode 4a of the two electrodes 4a and 4b is provided upstream of the filter body 42, and the other electrode 4b is provided downstream of the filter body 42.
- the electrodes 4 a and 4 b are disposed away from the end face of the filter main body 42, but the electrodes 4 a and 4 b may be arranged so as to be in contact with the end face of the filter main body 42.
- the filter body 42 has a large number of square holes 44 formed by partition walls 43 arranged in a honeycomb shape, and the holes 44 closed on the upstream side and opened on the downstream side and the holes 44 closed on the downstream side and opened on the upstream side are alternately adjacent to each other. Yes.
- the exhaust gas from the internal combustion engine enters the hole 44 opened on the upstream side, and the exhaust gas passes through the hole 44 opened on the downstream side over the entire surface of the partition wall 43. At this time, PM accumulates in the partition wall 43, and the purified exhaust gas flows downstream.
- the two electrodes 4a and 4b are each formed in a mesh shape. That is, the electrode 4a is stretched at a predetermined interval between the outer frame conductor wire 45 formed in a loop shape with substantially the same size and shape as the cross-sectional contour of the filter body 42, and inside and outside the outer frame conductor wire 45. A vertical conductor line 46 and a horizontal conductor line 47 are included.
- the electrode 4b has the same configuration.
- the entire filter body 42 is interposed between the electrodes 4a and 4b. Since it is sandwiched, the capacitance C proportional to the total amount of the collected PM can be detected.
- the two electrodes 4a and 4b are each formed in a mesh shape, so that the flow of the exhaust gas is not hindered.
- the pitch of the vertical conductor lines 46 and the horizontal conductor lines 47 may be the same as the vertical width and the horizontal width of the holes 44 so that the mesh of the electrodes 4 a and 4 b overlaps the mesh of the partition wall 43 appearing on the end face of the filter body 42. .
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- Processes For Solid Components From Exhaust (AREA)
Abstract
Provided is a PM sensor which is capable of detecting the amount of PM accumulated in a DPF by a simple structure. Two electrodes (4a, 4b) which are opposed to each other on an upstream side and a downstream side to form a capacitor are provided to a diesel particulate filter (DPF) (3) having a porous filter body (2) which is partitioned by a large number of separation walls, whereby the amount of PM collected in the DPF (3) is detected on the basis of the capacitance of the capacitor.
Description
本発明は、簡素な構成で正確にＤＰＦに溜まったＰＭの量を検出することができるＰＭセンサに関する。
The present invention relates to a PM sensor that can accurately detect the amount of PM accumulated in a DPF with a simple configuration.
ディーゼルエンジンなどの内燃機関を搭載した車両では、内燃機関から大気までの排気ガスの排出流路にディーゼルパティキュレートフィルタ（Diesel Particulate Filter；以下、ＤＰＦという）を設置し、排気ガスに含まれるＳＯＦ、ＳＯＯＴなどの粒子状物質（Particurate Matter）を捕集している（以下、これらをＰＭと総称する）。ＤＰＦは、主としてセラミックからなるハニカム細孔状（四角いものを含む）のフィルタにＰＭを一時的に捕集する部材である。
In a vehicle equipped with an internal combustion engine such as a diesel engine, a diesel particulate filter (hereinafter referred to as DPF) is installed in the exhaust gas exhaust passage from the internal combustion engine to the atmosphere, and the SOF contained in the exhaust gas, Particulate matter (Matter) such as SOOT is collected (hereinafter collectively referred to as PM). The DPF is a member that temporarily collects PM in a filter having a honeycomb pore shape (including a square one) mainly made of ceramic.
ＤＰＦに捕集されたＰＭが溜まると排圧が上昇しエンジン特性の低下をきたすため、堆積したＰＭを燃焼させる。この動作をＤＰＦ再生という。ＤＰＦ再生時には、排気温度を上昇させるための燃料噴射によって排気温度を上昇させ、ＤＰＦを昇温することで、ＤＰＦに捕集されているＰＭを燃焼させる。
∙ When PM collected in DPF accumulates, exhaust pressure rises and engine characteristics deteriorate, so the accumulated PM is combusted. This operation is called DPF regeneration. During DPF regeneration, the exhaust temperature is raised by fuel injection for raising the exhaust temperature, and the DPF is combusted by raising the temperature of the DPF.
このとき、ＤＰＦにＰＭが溜まりすぎていると、ＤＰＦ再生時の熱でＤＰＦが損傷してしまう。ＤＰＦにＰＭが溜まりすぎないうちにＤＰＦ再生するために、従来は、正確に堆積量を計測できないので、一般的に安全係数を比較的多く取りＤＰＦを再生している。
At this time, if PM accumulates too much in the DPF, the DPF will be damaged by the heat during the DPF regeneration. In order to regenerate the DPF before PM accumulates too much in the DPF, conventionally, since the amount of deposition cannot be measured accurately, the DPF is generally regenerated with a relatively large safety factor.
しかし、必要以上に短い間隔でＤＰＦ再生を実行すると燃料が余分に消費されることになり、燃費が悪化する。したがって、ＰＭの量を正確に検出し、最も適切な時期にＤＰＦ再生を行うようにするのが望ましい。
However, if DPF regeneration is performed at intervals shorter than necessary, extra fuel will be consumed and fuel consumption will deteriorate. Therefore, it is desirable to accurately detect the amount of PM and perform DPF regeneration at the most appropriate time.
従来、車両の走行距離が所定値に達するごとにＤＰＦ再生するようにしたのは、ＤＰＦに溜まったＰＭの量（ＰＭロード；フィルタの詰まり具合を表す）を検出するのが困難であるからである。例えば、特許文献２の技術では、ＤＰＦの上流側と下流側の排気ガスの圧力差からＰＭの量を検出している。しかし、排気の流量・温度は、内燃機関の状態変化に伴ってたえず変化しているため、圧力差から検出するＰＭの量は正確でない。また、特許文献１では、ＰＭの量を検出するという目的のために、車両走行上に必要のない空燃比変化を与えることになり、好ましくない。
Conventionally, DPF regeneration is performed every time the travel distance of the vehicle reaches a predetermined value because it is difficult to detect the amount of PM accumulated in the DPF (PM load; indicating the degree of filter clogging). is there. For example, in the technique of Patent Document 2, the amount of PM is detected from the pressure difference between exhaust gas upstream and downstream of the DPF. However, since the flow rate / temperature of the exhaust gas is constantly changing with the state change of the internal combustion engine, the amount of PM detected from the pressure difference is not accurate. Further, in Patent Document 1, for the purpose of detecting the amount of PM, an air-fuel ratio change which is not necessary for vehicle travel is given, which is not preferable.
また、実験室において、ＤＰＦに溜まったＰＭの量を検出する分析装置が知られているが、このような分析装置は大規模であり、車両には搭載できない。
Also, in the laboratory, an analyzer that detects the amount of PM accumulated in the DPF is known, but such an analyzer is large and cannot be mounted on a vehicle.
そこで、本発明の目的は、上記課題を解決し、簡素な構成で正確にＤＰＦに溜まったＰＭの量を検出することができるＰＭセンサを提供することにある。
Therefore, an object of the present invention is to provide a PM sensor that can solve the above-described problems and can accurately detect the amount of PM accumulated in the DPF with a simple configuration.
上記目的を達成するために本発明は、多数の隔壁で仕切られた多孔状のフィルタ本体を有するディーゼルパティキュレートフィルタ（ＤＰＦ）に、上流側と下流側で互いに対向してコンデンサを形成する２つの電極を設置し、上記コンデンサの静電容量から上記ＤＰＦに捕集されているＰＭの量が検出されるようにしたものである。
In order to achieve the above object, the present invention provides a diesel particulate filter (DPF) having a porous filter body partitioned by a number of partition walls, and forms two capacitors facing each other on the upstream side and the downstream side. An electrode is installed, and the amount of PM collected in the DPF is detected from the capacitance of the capacitor.
上記２つの電極のうち一方の電極を上記フィルタ本体の上流に設け、他方の電極を上記フィルタ本体の下流に設けてもよい。
One of the two electrodes may be provided upstream of the filter body, and the other electrode may be provided downstream of the filter body.
上記２つの電極を、それぞれ網目状に形成してもよい。
The above two electrodes may each be formed in a mesh shape.
本発明によれば、簡素な構成で正確にＤＰＦに溜まったＰＭの量を検出することができる。
According to the present invention, it is possible to accurately detect the amount of PM accumulated in the DPF with a simple configuration.
以下、本発明の一実施形態を添付図面に基づいて詳述する。
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
図１（ａ）に示されるように、本発明に係るＰＭセンサ１は、セラミックからなる多数の隔壁で仕切られた多孔状のフィルタ本体２を有するディーゼルパティキュレートフィルタ（ＤＰＦ）３に、上流側と下流側で互いに対向してコンデンサを形成する２つの電極４ａ，４ｂを設置し、そのコンデンサの静電容量からＤＰＦ３に捕集されているＰＭの量が検出されるようにしたものである。
As shown in FIG. 1 (a), a PM sensor 1 according to the present invention is provided upstream of a diesel particulate filter (DPF) 3 having a porous filter body 2 partitioned by a number of ceramic partition walls. And two electrodes 4a and 4b that form a capacitor opposite to each other on the downstream side, and the amount of PM collected in the DPF 3 is detected from the capacitance of the capacitor.
この実施形態では、電子制御装置（ＥＣＵ）５の内部に電極４ａ，４ｂが形成するコンデンサの静電容量を検出する検出部と、静電容量をＰＭの量に変換する演算部が設けられているものとする。
In this embodiment, a detection unit for detecting the capacitance of the capacitor formed by the electrodes 4a and 4b and a calculation unit for converting the capacitance to the amount of PM are provided inside the electronic control unit (ECU) 5. It shall be.
図１（ａ）のＰＭセンサ１は、図２（ａ）のようにモデル化して示される。すなわち、２つの同寸法平板状の電極を所定の電極間距離を隔てて対向させたコンデンサ２１に対し静電容量の検出部２２が接続されている。
The PM sensor 1 shown in FIG. 1A is modeled as shown in FIG. That is, the capacitance detection unit 22 is connected to a capacitor 21 in which two flat electrodes having the same size are opposed to each other with a predetermined distance between the electrodes.
次に、ＰＭセンサ１の動作を説明する。
Next, the operation of the PM sensor 1 will be described.
図１（ａ）のようにＤＰＦ３に捕集されたＰＭの量が少ない状態から、徐々にＰＭの量が増加し、図１（ｂ）のようにＤＰＦ３に捕集されたＰＭの量が多い状態になったとする。図１（ｂ）はＤＰＦ３のハッチングを図１（ａ）より濃くすることでＰＭの量が多いことを表している。このとき、ＰＭセンサ１のモデルは、図２（ａ）のようにコンデンサ２１の静電容量が小さい値Ｃ0である状態から図２（ｂ）のようにコンデンサ２１の静電容量が大きい値Ｃ1である状態に変化する（Ｃ1＞Ｃ0）。
From the state where the amount of PM collected in the DPF 3 is small as shown in FIG. 1A, the amount of PM gradually increases, and as shown in FIG. 1B, the amount of PM collected in the DPF 3 is large. Suppose that it is in a state. FIG. 1B shows that the amount of PM is large by making the hatching of the DPF 3 darker than that in FIG. At this time, PM model of the sensor 1, the value the capacitance of the capacitor 21 is large as shown in FIG. 2 (b) from the state is a value C 0 low capacitance of the capacitor 21 as shown in FIG. 2 (a) changes to the state is a C 1 (C 1> C 0 ).
検出部２２では、コンデンサ２１の静電容量を検出する。このとき、静電容量をＣ、電極間の媒体の誘電率をε、電極の面積をＳ、電極間の距離をｄとすると、
Detecting unit 22 detects the capacitance of capacitor 21. At this time, if the capacitance is C, the dielectric constant of the medium between the electrodes is ε, the area of the electrodes is S, and the distance between the electrodes is d,
となる。よって、誘電率εが大きくなるか電極間距離ｄが小さくなるかすれば、静電容量Ｃは大きくなる。
It becomes. Therefore, the capacitance C increases as the dielectric constant ε increases or the inter-electrode distance d decreases.
ここで、本発明者らは、ＰＭセンサ１内に設置した２つの電極４ａ，４ｂが形成するコンデンサの静電容量Ｃが捕集されたＰＭの量によってどのように変化するかを実験により調べた。すなわち、ＰＭセンサ１の下流から吸引することによって上流から下流に空気を流し、そのＰＭセンサ１の上流において空気中にＰＭを少量ずつ投入し、静電容量Ｃの変化を記録した。その結果、図３に示されるように、ＰＭの投入量に対してほぼ直線的に静電容量Ｃが増大することが分かった。すなわち、静電容量Ｃは、ＰＭセンサ１に捕集されたＰＭの量を正確に示す。
Here, the present inventors investigated through experiments how the capacitance C of the capacitor formed by the two electrodes 4a and 4b installed in the PM sensor 1 changes depending on the amount of collected PM. It was. That is, by sucking from the downstream of the PM sensor 1, air was flown from the upstream to the downstream, and PM was gradually added into the air upstream of the PM sensor 1, and the change in the capacitance C was recorded. As a result, as shown in FIG. 3, it was found that the capacitance C increased almost linearly with respect to the amount of PM input. That is, the capacitance C accurately indicates the amount of PM collected by the PM sensor 1.
静電容量Ｃが捕集されたＰＭの量に比例して増加する理由としては、電極４ａ，４ｂ間に導体である炭素が入ることで、見かけ上、電極間距離ｄが小さくなり静電容量Ｃが大きくなる、あるいは、電極４ａ，４ｂ間の媒体中にＰＭが増加して誘電率εが大きくなり静電容量Ｃが大きくなると考えられる。
The reason why the capacitance C increases in proportion to the amount of collected PM is that the conductor carbon is inserted between the electrodes 4a and 4b, so that the inter-electrode distance d is apparently reduced and the capacitance is increased. It is conceivable that C increases or PM increases in the medium between the electrodes 4a and 4b and the dielectric constant ε increases and the capacitance C increases.
以上説明したように、本発明のＰＭセンサ１は、ＤＰＦ３に、１個以上の隔壁を挟んでコンデンサを形成する２つの電極４ａ，４ｂを設置したので、コンデンサの静電容量ＣからＤＰＦ３に捕集されているＰＭの量を正確に検出することができる。本発明のＰＭセンサ１は、電極４ａ，４ｂを配置するだけの簡素な構成であるため、製造が容易であり、コストが安いという利点がある。
As described above, in the PM sensor 1 of the present invention, the two electrodes 4a and 4b that form a capacitor with one or more partition walls interposed in the DPF 3, the capacitance C of the capacitor is captured by the DPF 3. The amount of PM collected can be accurately detected. Since the PM sensor 1 of the present invention has a simple configuration in which only the electrodes 4a and 4b are arranged, there are advantages that manufacturing is easy and cost is low.
なお、ＰＭセンサ１は、前述した動作原理から、上流側と下流側の２つの電極４ａ，４ｂをフィルタ本体２の長手方向のどこに設置しても、電極４ａ，４ｂ間に捕集されているＰＭの量が静電容量から検出される。しかし、実際には、フィルタ本体２を両端から挟むように電極４ａ，４ｂを設置するのが望ましい。
The PM sensor 1 is collected between the electrodes 4a and 4b, regardless of where the two electrodes 4a and 4b on the upstream side and the downstream side are installed in the longitudinal direction of the filter body 2 due to the operation principle described above. The amount of PM is detected from the capacitance. However, in practice, it is desirable to install the electrodes 4a and 4b so as to sandwich the filter body 2 from both ends.
次に、本発明の具体的な実施形態を説明する。
Next, specific embodiments of the present invention will be described.
図４に示されるように、本発明のＰＭセンサ４１は、２つの電極４ａ，４ｂのうち一方の電極４ａをフィルタ本体４２の上流に設け、他方の電極４ｂをフィルタ本体４２の下流に設けたものである。なお、図４では、電極４ａ，４ｂがフィルタ本体４２の端面から離れて設置されているが、電極４ａ，４ｂがそれぞれフィルタ本体４２の端面に接するように配置してもよい。
As shown in FIG. 4, in the PM sensor 41 of the present invention, one electrode 4a of the two electrodes 4a and 4b is provided upstream of the filter body 42, and the other electrode 4b is provided downstream of the filter body 42. Is. In FIG. 4, the electrodes 4 a and 4 b are disposed away from the end face of the filter main body 42, but the electrodes 4 a and 4 b may be arranged so as to be in contact with the end face of the filter main body 42.
フィルタ本体４２はハニカム状に並べられた隔壁４３によって形成された四角い孔４４が多数並んでおり、上流側が閉じ下流側が開いた孔４４と下流側が閉じ上流側が開いた孔４４が交互に隣接している。上流側が開いた孔４４に内燃機関からの排気ガスが入り、隔壁４３の全面において排気ガスが下流側が開いた孔４４に抜ける。このとき隔壁４３にＰＭが溜まり、浄化された排気ガスが下流に出ていく。
The filter body 42 has a large number of square holes 44 formed by partition walls 43 arranged in a honeycomb shape, and the holes 44 closed on the upstream side and opened on the downstream side and the holes 44 closed on the downstream side and opened on the upstream side are alternately adjacent to each other. Yes. The exhaust gas from the internal combustion engine enters the hole 44 opened on the upstream side, and the exhaust gas passes through the hole 44 opened on the downstream side over the entire surface of the partition wall 43. At this time, PM accumulates in the partition wall 43, and the purified exhaust gas flows downstream.
本発明のＰＭセンサ４１は、２つの電極４ａ，４ｂがそれぞれ網目状に形成されている。すなわち、電極４ａは、フィルタ本体４２の断面輪郭とほぼ同じ大きさ及び形状でループ状に形成された外枠導体線４５と、外枠導体線４５の内側に縦横それぞれ所定間隔で張設された縦導体線４６及び横導体線４７とにより構成される。電極４ｂについても同様の構成である。
In the PM sensor 41 of the present invention, the two electrodes 4a and 4b are each formed in a mesh shape. That is, the electrode 4a is stretched at a predetermined interval between the outer frame conductor wire 45 formed in a loop shape with substantially the same size and shape as the cross-sectional contour of the filter body 42, and inside and outside the outer frame conductor wire 45. A vertical conductor line 46 and a horizontal conductor line 47 are included. The electrode 4b has the same configuration.
本発明のＰＭセンサ４１によれば、一方の電極４ａをフィルタ本体４２の上流に設け、他方の電極４ｂをフィルタ本体４２の下流に設けたので、フィルタ本体４２の全体が電極４ａ，４ｂ間に挟まれるため、捕集されているＰＭの全量に比例する静電容量Ｃを検出することができる。
According to the PM sensor 41 of the present invention, since one electrode 4a is provided upstream of the filter body 42 and the other electrode 4b is provided downstream of the filter body 42, the entire filter body 42 is interposed between the electrodes 4a and 4b. Since it is sandwiched, the capacitance C proportional to the total amount of the collected PM can be detected.
また、本発明のＰＭセンサ４１によれば、２つの電極４ａ，４ｂがそれぞれ網目状に形成されているため、排気ガスの流れを妨げることがない。電極４ａ，４ｂの網目は、フィルタ本体４２の端面に表れている隔壁４３の網目と重なるように、縦導体線４６及び横導体線４７のピッチを孔４４の縦幅・横幅と同じにするとよい。
Further, according to the PM sensor 41 of the present invention, the two electrodes 4a and 4b are each formed in a mesh shape, so that the flow of the exhaust gas is not hindered. The pitch of the vertical conductor lines 46 and the horizontal conductor lines 47 may be the same as the vertical width and the horizontal width of the holes 44 so that the mesh of the electrodes 4 a and 4 b overlaps the mesh of the partition wall 43 appearing on the end face of the filter body 42. .
１，４１ ＰＭセンサ
２，４２ フィルタ本体
３ ディーゼルパティキュレートフィルタ（ＤＰＦ）
４ａ，４ｂ 電極
４３ 隔壁
４４ 孔
５ ＥＣＵ 1,41PM sensor 2,42 Filter body 3 Diesel particulate filter (DPF)
4a,4b electrode 43 partition 44 hole 5 ECU
２，４２ フィルタ本体
３ ディーゼルパティキュレートフィルタ（ＤＰＦ）
４ａ，４ｂ 電極
４３ 隔壁
４４ 孔
５ ＥＣＵ 1,41
4a,
Claims (3)
- 多数の隔壁で仕切られた多孔状のフィルタ本体を有するディーゼルパティキュレートフィルタ（ＤＰＦ）に、上流側と下流側で互いに対向してコンデンサを形成する２つの電極を設置し、上記コンデンサの静電容量から上記ＤＰＦに捕集されているＰＭの量が検出されるようにしたことを特徴とするＰＭセンサ。 A diesel particulate filter (DPF) having a porous filter body partitioned by a large number of partition walls is provided with two electrodes forming a capacitor facing each other on the upstream side and the downstream side, and the capacitance of the capacitor A PM sensor characterized in that the amount of PM trapped in the DPF is detected.
- 上記２つの電極のうち一方の電極を上記フィルタ本体の上流に設け、他方の電極を上記フィルタ本体の下流に設けたことを特徴とする請求項１記載のＰＭセンサ。 The PM sensor according to claim 1, wherein one of the two electrodes is provided upstream of the filter body, and the other electrode is provided downstream of the filter body.
- 上記２つの電極を、それぞれ網目状に形成したことを特徴とする請求項１又は２記載のＰＭセンサ。 The PM sensor according to claim 1 or 2, wherein each of the two electrodes is formed in a mesh shape.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009162104A JP2011017280A (en) | 2009-07-08 | 2009-07-08 | Pm sensor |
| JP2009-162104 | 2009-07-08 |
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| Publication Number | Publication Date |
|---|---|
| WO2011004747A1 true WO2011004747A1 (en) | 2011-01-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| PCT/JP2010/061146 WO2011004747A1 (en) | 2009-07-08 | 2010-06-30 | Pm sensor |
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| WO (1) | WO2011004747A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107250781A (en) * | 2015-02-20 | 2017-10-13 | 五十铃自动车株式会社 | Sensor |
| FR3069017A1 (en) * | 2017-07-12 | 2019-01-18 | Psa Automobiles Sa | METHOD FOR CONFIRMING A DIAGNOSTIC OF CLOSING OF A PARTICLE FILTER |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002021537A (en) * | 2000-07-03 | 2002-01-23 | Nissan Diesel Motor Co Ltd | Exhaust emission control device for diesel engine |
| JP2009097410A (en) * | 2007-10-16 | 2009-05-07 | Toyota Motor Corp | Particulate matter collection amount estimation device, and filter regeneration system in particulate filter |
-
2009
- 2009-07-08 JP JP2009162104A patent/JP2011017280A/en active Pending
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2010
- 2010-06-30 WO PCT/JP2010/061146 patent/WO2011004747A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002021537A (en) * | 2000-07-03 | 2002-01-23 | Nissan Diesel Motor Co Ltd | Exhaust emission control device for diesel engine |
| JP2009097410A (en) * | 2007-10-16 | 2009-05-07 | Toyota Motor Corp | Particulate matter collection amount estimation device, and filter regeneration system in particulate filter |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107250781A (en) * | 2015-02-20 | 2017-10-13 | 五十铃自动车株式会社 | Sensor |
| EP3260854A4 (en) * | 2015-02-20 | 2018-08-08 | Isuzu Motors Limited | Sensor |
| FR3069017A1 (en) * | 2017-07-12 | 2019-01-18 | Psa Automobiles Sa | METHOD FOR CONFIRMING A DIAGNOSTIC OF CLOSING OF A PARTICLE FILTER |
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| JP2011017280A (en) | 2011-01-27 |
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