JPH0128256Y2

JPH0128256Y2 -

Info

Publication number: JPH0128256Y2
Application number: JP1983201542U
Authority: JP
Priority date: 1983-12-28
Filing date: 1983-12-28
Publication date: 1989-08-29
Also published as: JPS60110618U

Description

【考案の詳細な説明】（産業上の利用分野）本考案は、デイーゼルエンジンの排気中に含ま
れる未燃カーボン等の微粒子成分（パテイキユレ
ート）を排気通路に設けた触媒付捕集部材により
捕集するようにしたデイーゼルエンジンの排気浄
化装置に関し、特に上記触媒付捕集部材を再生す
る対策に関する。[Detailed description of the invention] (Field of industrial application) This invention collects particulate components (particulate matter) such as unburned carbon contained in the exhaust gas of diesel engines using a catalyst-equipped collection member installed in the exhaust passage. The present invention relates to an exhaust gas purification device for a diesel engine, and particularly relates to a measure for regenerating the catalyst-equipped collection member.

（従来技術）従来より、この種の、排気通路に微粒子成分捕
集用の捕集部材（フイルタ部材）を配置せしめた
デイーゼルエンジンの排気浄化装置はよく知られ
ているが、このものでは長期間経過すると捕集さ
れた微粒子成分の堆積により捕集部材に目詰まり
が生じてエンジン出力が低下する等の問題があ
る。この問題に対処するために定期的に上記捕集
部材の目詰まりを解消してその再生を行う必要が
ある。(Prior art) This type of exhaust purification device for a diesel engine is well known in which a collection member (filter member) for collecting particulate components is placed in the exhaust passage. As time passes, the collection member becomes clogged due to the accumulation of collected particulate components, resulting in problems such as a decrease in engine output. To deal with this problem, it is necessary to periodically unclog the collection member and regenerate it.

そして、このような捕集部材の再生を行う方式
の一例として、従来、例えば特開昭56−56921号
公報等に開示されているように、排気通路に配設
する捕集部材を、排気中の未燃ガスを酸化燃焼さ
せる触媒作用を併有する触媒付のものとするとと
もに、該触媒付捕集部材よりも上流側の排気通路
に排気ガスを加熱する電気発熱体（電気ヒータ）
等の加熱手段を設け、該加熱手段により加熱され
た排気ガスを再生ガスとして触媒付捕集部材に導
いて該触媒付捕集部材での酸化反応によりさらに
高温にし、この高温となつた排気ガスによつて捕
集部材に捕集されている微粒子成分を燃焼除去す
るようにしたものが提案されている。 As an example of a method for regenerating such a collection member, conventionally, for example, as disclosed in Japanese Patent Laid-Open No. 56-56921, etc., a collection member disposed in an exhaust passage is regenerated during exhaust gas. an electric heating element (electric heater) that heats the exhaust gas in an exhaust passage upstream of the catalyst-equipped collection member;
A heating means is provided, and the exhaust gas heated by the heating means is guided as regeneration gas to a collection member with a catalyst, and is further raised to a high temperature by an oxidation reaction in the collection member with a catalyst, and this high temperature exhaust gas is A system has been proposed in which particulate components collected in a collection member are removed by combustion.

（考案が解決しようとする問題点）ところで、この提案のものでは、触媒付捕集部
材での排気ガスの再燃焼による発熱を利用して微
粒子成分を加熱燃焼させるため、加熱手段の発熱
体容量、バツテリ容量等をある程度は小さくする
ことができる。しかし、微粒子成分を効果的に燃
焼除去するには約600℃以上の高温度への加熱が
必要であること（触媒付捕集部材の場合その酸化
反応により更に高温になることから再生ガスの温
度としては450℃以上必要であること）を考慮し
た場合、上記加熱手段の発熱体容量、バツテリ容
量をあまりに小さく設定することはできないもの
である。(Problem to be solved by the invention) By the way, in this proposal, the particulate components are heated and combusted using the heat generated by the re-combustion of the exhaust gas in the catalytic collection member, so the capacity of the heating element of the heating means is reduced. , battery capacity, etc. can be reduced to some extent. However, in order to effectively burn and remove particulate components, it is necessary to heat the regeneration gas to a high temperature of approximately 600℃ or higher (in the case of a catalyst-equipped collection member, the temperature of the regenerated gas increases even further due to the oxidation reaction). (450° C. or higher is required), it is impossible to set the heating element capacity and battery capacity of the heating means too small.

そこで、上記の触媒付捕集部材を加熱再生する
ための再生ガスを、電気発熱体と該電気発熱体か
らの熱エネルギを蓄熱する蓄熱材との組合せによ
つて加熱するようにすることにより、その放熱面
積を増大させて、再生ガスの加温を効率良く行い
触媒付捕集部材を効果的に再生しながら、電気発
熱体やバツテリの容量を従来のものよりもさらに
小さく設定できるようにすることが考えられる。 Therefore, by heating the regeneration gas for heating and regenerating the above-described catalyst-equipped collection member using a combination of an electric heating element and a heat storage material that stores thermal energy from the electric heating element, By increasing its heat dissipation area, the capacity of the electric heating element and battery can be set even smaller than conventional ones, while efficiently heating the regenerated gas and effectively regenerating the catalyst-equipped collection member. It is possible that

ところが、その場合、蓄熱材の利用によつて電
気発熱体およびバツテリの容量を小さくした分だ
け電気発熱体からの熱エネルギを蓄熱材に十分に
蓄熱するまでの時間が長くかかる。特に、再生ガ
スとして排気ガスを用い、かつ排気通路に上記蓄
熱材および電気発熱体を配設した場合、エンジン
の運転状態によつては（例えば燃料噴射量の多い
高負荷運転時）、排気ガス温度が捕集部材を再生
可能な所定温度（例えば450℃）以上になること
があり、このときには逆に蓄熱材の蓄熱が排気ガ
スによつて奪われて蓄熱量が著しく低下する。こ
のため、例えば短時間のエンジン運転を繰り返す
ときには蓄熱材での熱エネルギの蓄熱不足により
再生ガスが高温度まで加熱昇温されず、捕集部材
を確実に再生することができないという問題が生
じる。また、上記の如く排気ガス温度が再生可能
な所定温度以上になるときは、燃料量が多い運転
状態であることから、排気ガス中の酸素濃度が低
くなる傾向にあり、触媒付捕集部材での酸化反応
が十分に行われないという問題がある。 However, in this case, it takes a longer time to sufficiently store the thermal energy from the electric heating element in the heat storage material due to the reduction in the capacity of the electric heating element and the battery due to the use of the heat storage material. In particular, when exhaust gas is used as the regeneration gas and the heat storage material and electric heating element are disposed in the exhaust passage, depending on the operating condition of the engine (for example, during high-load operation with a large amount of fuel injection), the exhaust gas may The temperature may reach a predetermined temperature (for example, 450° C.) at which the collection member can be regenerated, and in this case, the heat stored in the heat storage material is conversely taken away by the exhaust gas, and the amount of heat stored is significantly reduced. For this reason, for example, when the engine is repeatedly operated for a short period of time, the problem arises that the regeneration gas is not heated to a high temperature due to insufficient storage of thermal energy in the heat storage material, and the collection member cannot be reliably regenerated. In addition, when the exhaust gas temperature exceeds the predetermined regeneration temperature as described above, the oxygen concentration in the exhaust gas tends to decrease because the amount of fuel is large, and the catalyst-equipped collection member There is a problem that the oxidation reaction is not carried out sufficiently.

（考案の目的）本考案はかかる諸点に鑑みてなされたものであ
り、その目的とするところは、デイーゼルエンジ
ンの排気ガスの温度が所定温度未満のときは、排
気ガスを蓄熱材に流通させることにより、該蓄熱
材と排気ガスとを熱交換させて排気ガスを再生可
能な温度に加熱昇温させる一方、排気ガス温度が
所定温度以上のときは、排気ガスを蓄熱材に流通
させずに直接捕集部材に導入することにより、蓄
熱材の蓄熱が排気ガスにより奪われるのを防止し
ながら、排気ガス自体の熱エネルギそのもので捕
集部材を本来の目詰まり検出を待たずに再生し、
しかも、その時の酸素濃度が所定値以下のときに
はエアを供給して触媒付捕集部材の酸化反応を促
進させることによつて再生を良好に行うことによ
り、蓄熱材の使用により電気発熱体およびバツテ
リの容量を小さく設定しつつ、蓄熱材の蓄熱不足
を可及的に抑制し、短時間のエンジン運転を繰り
返しても捕集部材の再生を良好に行い得るように
することにある。(Purpose of the invention) The present invention was made in view of the above points, and its purpose is to cause the exhaust gas to flow through the heat storage material when the temperature of the exhaust gas from a diesel engine is below a predetermined temperature. By exchanging heat between the heat storage material and the exhaust gas, the exhaust gas is heated to a regenerable temperature, while when the exhaust gas temperature is higher than a predetermined temperature, the exhaust gas is directly heated without passing through the heat storage material. By introducing it into the collection member, it prevents the heat stored in the heat storage material from being taken away by the exhaust gas, while regenerating the collection member using the thermal energy of the exhaust gas itself without waiting for the original clogging detection.
Moreover, when the oxygen concentration at that time is below a predetermined value, air is supplied to promote the oxidation reaction of the catalyst-equipped collection member, thereby achieving good regeneration. The purpose is to suppress insufficient heat storage in the heat storage material as much as possible while setting the capacity of the heat storage material to be small, and to enable good regeneration of the collection member even after repeated short-term engine operations.

（考案の構成）上記目的の達成のため、本考案の構成は、排気
通路にカーボン粒子等の微粒子成分を捕集する触
媒付捕集部材を設けるとともに、該触媒付捕集部
材に捕集された微粒子成分を燃焼除去するための
再生ガスを加熱する再生ガス加熱装置を設けてな
るデイーゼルエンジンの排気浄化装置を対象とす
る。そして、上記再生ガス加熱装置は、電気発熱
体と、該電気発熱体からの熱エネルギを蓄熱する
とともに放熱により上記再生ガスを加熱する蓄熱
材とを備える。さらに、上記捕集部材より上流側
排気通路であつて上記再生ガス加熱装置をバイパ
スするバイパス通路と、上記捕集部材より上流側
排気通路の排気ガスの温度を検出する排気ガス温
度検出器と、排気ガス中の酸素濃度を把握する排
気ガスセンサと、上記捕集部材上流側の排気通路
にエアを供給するエア供給装置と、上記排気ガス
温度検出器の出力を受けて、排気ガス温度が所定
温度未満のときは排気ガスを上記再生ガス加熱装
置介在の排気通路を介して捕集部材上流側へ導入
させ、排気ガス温度が所定温度以上のときは排気
ガスを上記バイパス通路を介して捕集部材上流側
へ導入させるよう排気ガスの流通路を切換制御す
る通路切換制御手段と、上記排気ガス温度検出器
および上記排気ガスセンサの出力を受けて排気ガ
ス温度が所定温度以上に上昇し、かつ排気ガス中
の酸素濃度が設定値以下のときに上記エア供給装
置を作動させるように制御するエア供給制御装置
とを設けたものである。(Structure of the invention) In order to achieve the above object, the structure of the invention is to provide a catalyst-equipped collection member for collecting particulate components such as carbon particles in the exhaust passage, and also provide a catalyst-equipped collection member for collecting particulate components such as carbon particles. The present invention is directed to an exhaust gas purification device for a diesel engine, which is equipped with a regeneration gas heating device that heats regeneration gas to burn off particulate components. The regeneration gas heating device includes an electric heating element and a heat storage material that stores thermal energy from the electric heating element and heats the regeneration gas by heat radiation. Further, a bypass passage that is an exhaust passage upstream of the collection member and bypasses the regeneration gas heating device, and an exhaust gas temperature detector that detects the temperature of exhaust gas in the exhaust passage upstream of the collection member; An exhaust gas sensor detects the oxygen concentration in the exhaust gas, an air supply device supplies air to the exhaust passage on the upstream side of the collection member, and receives the output of the exhaust gas temperature detector to adjust the exhaust gas temperature to a predetermined temperature. When the exhaust gas temperature is less than a predetermined temperature, the exhaust gas is introduced into the collection member upstream through the exhaust passage provided by the regeneration gas heating device, and when the exhaust gas temperature is higher than the predetermined temperature, the exhaust gas is introduced into the collection member through the bypass passage. passage switching control means for switching and controlling the exhaust gas flow passage so as to introduce the exhaust gas to the upstream side; and an air supply control device that controls the air supply device to operate when the oxygen concentration in the air is below a set value.

このことにより、エンジンの排気ガス温度が捕
集部材の再生可能な所定温度未満のときには、排
気ガスが再生ガス加熱装置を通つて捕集部材上流
側へ導入されることにより、この再生ガス加熱装
置における蓄熱材と排気ガスとが熱交換して、排
気ガスが蓄熱材によつて効率良く再生可能な温度
に昇温し、捕集部材の目詰まり時の再生を早期に
達成できる。 As a result, when the exhaust gas temperature of the engine is lower than the predetermined temperature at which the collection member can be regenerated, the exhaust gas is introduced into the upstream side of the collection member through the regeneration gas heating device. The heat storage material and the exhaust gas exchange heat, and the exhaust gas is heated to a temperature at which it can be efficiently regenerated by the heat storage material, and regeneration when the collection member is clogged can be achieved at an early stage.

一方、排気ガス温度が上記所定温度以上のとき
には、上記再生ガス加熱装置への排気ガスの流通
が停止されて、排気ガスがバイパス通路を介して
直接捕集部材へ導入されるので、蓄熱材の蓄熱が
排気ガスにより奪われるのを防止しながら、排気
ガス自体の熱エネルギそのもので捕集部材が本来
の目詰まり検出を待たずに再生されることにな
る。しかも、その時の排気ガス中の酸素濃度が所
定値以下のときには、上記捕集部材にエアが送給
されるので、触媒付捕集部材の酸化反応が促進さ
れて、その再生を良好に行うことができる。 On the other hand, when the exhaust gas temperature is above the predetermined temperature, the flow of exhaust gas to the regeneration gas heating device is stopped and the exhaust gas is directly introduced into the collection member via the bypass passage, so that the heat storage material is While preventing heat storage from being taken away by the exhaust gas, the collection member is regenerated by the thermal energy of the exhaust gas itself without waiting for the original clogging detection. Moreover, when the oxygen concentration in the exhaust gas at that time is below a predetermined value, air is supplied to the collection member, so that the oxidation reaction of the catalyst-equipped collection member is promoted and its regeneration is performed well. I can do it.

（考案の効果）したがつて、本考案によれば、デイーゼルエン
ジンの排気ガス温度が所定温度未満のときは、蓄
熱材と排気ガスとを熱交換させることで、この排
気ガスを蓄熱材で再生可能な温度に効率良く昇温
させて捕集部材の目詰まり時の再生を早期に達成
できる。一方、排気ガス温度が所定温度以上のと
きは、蓄熱材の蓄熱が排気ガスにより奪われるの
を防止しながら、排気ガス自体の熱エネルギその
もので捕集部材を本来の目詰まり検出を待たずに
再生でき、しかもその時の触媒付捕集部材の酸化
反応を促進させることでその再生を良好に行うこ
とができる。よつて、蓄熱材を使用して電気発熱
体およびバツテリの容量を小さく設定しながら、
短時間のエンジン運転を繰り返しても捕集部材を
良好に再生することができ、ひいてはバツテリの
消費電力の低減、触媒付捕集部材に対する再生イ
ンターバルの安全サイドへの設定等を図ることが
できるものである。(Effect of the invention) Therefore, according to the invention, when the exhaust gas temperature of a diesel engine is below a predetermined temperature, the exhaust gas is regenerated with the heat storage material by exchanging heat between the heat storage material and the exhaust gas. By efficiently raising the temperature to a possible temperature, it is possible to quickly regenerate the collection member when it becomes clogged. On the other hand, when the exhaust gas temperature is above a predetermined temperature, while preventing the heat storage material from being taken away by the exhaust gas, the thermal energy of the exhaust gas itself is used to collect the collection member without waiting for the original clogging detection. It can be regenerated, and the regeneration can be performed satisfactorily by promoting the oxidation reaction of the catalyst-equipped collection member at that time. Therefore, while using a heat storage material and setting the capacity of the electric heating element and battery to a small value,
It is possible to regenerate the collection member satisfactorily even after repeated short-term engine operation, which in turn makes it possible to reduce battery power consumption and set the regeneration interval for the catalyst-equipped collection member on the safe side. It is.

（実施例）以下、本考案の実施例を図面に基づいて詳細に
説明する。(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

第１図は本考案の実施例に係るデイーゼルエン
ジンの排気浄化装置の全体構成を示し、１はデイ
ーゼルエンジン、２は該エンジン１に吸気を供給
するための吸気通路、３はエンジン１からの排気
ガスを外部に排出するための排気通路であつて、
該排気通路３の途中には排気ガス中のカーボン粒
子等の微粒子成分を捕集する触媒付捕集部材４が
配設されている。該触媒付捕集部材４は、セラミ
ツク等の多孔質材料によりハニカム状に形成さ
れ、そのハニカム孔の開口端はハニカム体の両端
部で交互に閉塞され、かつ排気ガスに接触する表
面には貴金属あるいは卑金属による酸化触媒がコ
ーテイングされており、一端部のハニカム孔開口
端から流入した排気ガスが通気性を持つ多孔質隔
壁を通つて他端部のハニカム孔開口部から流出す
る間に上記多孔質隔壁によつて排気ガス中の微粒
子成分を捕集するとともに、酸化触媒によつて排
気ガス中の未燃ガスを酸化反応させるものであ
る。 FIG. 1 shows the overall configuration of a diesel engine exhaust purification device according to an embodiment of the present invention, in which 1 is a diesel engine, 2 is an intake passage for supplying intake air to the engine 1, and 3 is an exhaust gas from the engine 1. An exhaust passage for discharging gas to the outside,
A catalyst-equipped collection member 4 is disposed in the middle of the exhaust passage 3 to collect particulate components such as carbon particles in the exhaust gas. The catalyst-equipped collection member 4 is formed in a honeycomb shape from a porous material such as ceramic, the open ends of the honeycomb holes are alternately closed at both ends of the honeycomb body, and the surface in contact with the exhaust gas is coated with a noble metal. Alternatively, an oxidation catalyst made of a base metal is coated, and the exhaust gas flowing in from the opening end of the honeycomb hole at one end passes through a porous partition wall with air permeability and flows out from the opening end of the honeycomb hole at the other end. Particulate components in the exhaust gas are collected by the partition walls, and unburned gas in the exhaust gas is subjected to an oxidation reaction by the oxidation catalyst.

上記触媒付捕集部材４よりも上流側の排気通路
３には再生ガス供給通路５の下流端が開口され、
該再生ガス供給通路５の上流端はエアポンプ６に
連通され、再生ガス供給通路５の途中部は連通路
７を介して上記排気通路３の再生ガス供給通路５
下流端との接続部よりも上流側に連通されてお
り、上記排気通路３と並列の排気通路を構成して
いる。つまり、上記捕集部材４よりも上流側排気
通路３は上記再生ガス供給通路５に介設される後
述の再生ガス加熱装置１５をバイパスするバイパ
ス通路を構成している。また、上記排気通路３の
再生ガス供給通路５下流端との接続部と、連通路
７との接続部との間には排気バイパス通路８の上
流端が開口され、該排気バイパス通路８の下流端
は上記捕集部材４よりも下流端の排気通路３に開
口されている。 A downstream end of a regeneration gas supply passage 5 is opened in the exhaust passage 3 on the upstream side of the catalyst-equipped collection member 4,
The upstream end of the regeneration gas supply passage 5 is communicated with an air pump 6, and the middle part of the regeneration gas supply passage 5 is connected to the regeneration gas supply passage 5 of the exhaust passage 3 via a communication passage 7.
It communicates with the upstream side of the connection part with the downstream end, and constitutes an exhaust passage parallel to the exhaust passage 3. That is, the exhaust passage 3 upstream of the collection member 4 constitutes a bypass passage that bypasses a regeneration gas heating device 15, which will be described later, which is interposed in the regeneration gas supply passage 5. Further, an upstream end of an exhaust bypass passage 8 is opened between the connection part of the exhaust passage 3 with the downstream end of the regeneration gas supply passage 5 and the connection part with the communication passage 7. The end is opened to the exhaust passage 3 at the downstream end of the collecting member 4.

また、上記排気通路３の連通路７との接続部に
は開度調整可能な常時閉の電磁式の第１開閉弁９
が配設され、該第１開閉弁９は、閉じた状態では
連通路７の排気通路３との連通を遮断するととも
に第１開閉弁９上下流側の排気通路３，３同士を
連通させ、図で仮想線にて示すように開くと連通
路７を第１開閉弁９上流側の排気通路３に連通さ
せるとともに該第１開閉弁９上下流側の排気通路
３，３同士の連通を遮断するように開閉する。ま
た、上記排気通路３の排気バイパス通路８上流端
との接続部には開度調整可能な常時閉の電磁式の
第２開閉弁１０が配設され、該第２開閉弁１０
は、閉じた状態では排気バイパス通路８の排気通
路３との連通を遮断するとともに第２開閉弁１０
上下流側の排気通路３，３同士を連通させ、図で
仮想線にて示すように開くと排気バイパス通路８
を第２開閉弁１０上流側の排気通路３に連通させ
るとともに該第２開閉弁１０上下流側の排気通路
３，３同士の連通を遮断するように開閉する。さ
らに、上記再生ガス供給通路５の連通路７との接
続部よりも下流側には該再生ガス供給通路５を開
閉する常時閉の電磁式の第３開閉弁１１が配設さ
れている。そして、全開閉弁９〜１１を全開状態
とすることにより、エンジン１の排気ガスを、触
媒付捕集部材４に捕集された微粒子成分を燃焼除
去させるための再生ガスとして連通路７および再
生ガス供給通路５を通して捕集部材４に供給する
ようにしている。また、上記第１開閉弁９を閉じ
かつ第２および第３開閉弁１０，１１を開いた状
態でエアポンプ６を作動させることにより、該エ
アポンプ６から吐出されたエアを再生ガス供給通
路５を通して捕集部材４上流側の排気通路３に供
給するようにしたエア供給装置１２が構成されて
いる。 Further, at the connection part of the exhaust passage 3 with the communication passage 7, a normally closed electromagnetic first on-off valve 9 whose opening degree can be adjusted is provided.
is disposed, and the first on-off valve 9, in the closed state, cuts off communication between the communication passage 7 and the exhaust passage 3, and allows the exhaust passages 3, 3 on the upstream and downstream sides of the first on-off valve 9 to communicate with each other, When opened as shown by the imaginary line in the figure, the communication passage 7 is communicated with the exhaust passage 3 on the upstream side of the first on-off valve 9, and communication between the exhaust passages 3, 3 on the upstream and downstream sides of the first on-off valve 9 is cut off. Open and close as shown. Further, a normally closed electromagnetic second on-off valve 10 whose opening degree is adjustable is disposed at the connection portion of the exhaust passage 3 with the upstream end of the exhaust bypass passage 8.
In the closed state, the exhaust bypass passage 8 is cut off from communicating with the exhaust passage 3, and the second on-off valve 10 is closed.
When the upstream and downstream exhaust passages 3 and 3 are communicated with each other and opened as shown by the imaginary line in the figure, an exhaust bypass passage 8 is formed.
is opened and closed so as to communicate with the exhaust passage 3 on the upstream side of the second on-off valve 10, and to block communication between the exhaust passages 3, 3 on the upstream and downstream sides of the second on-off valve 10. Further, a normally-closed electromagnetic third on-off valve 11 for opening and closing the regeneration gas supply passage 5 is disposed downstream of the connection portion of the regeneration gas supply passage 5 with the communication passage 7 . By fully opening the full open/close valves 9 to 11, the exhaust gas from the engine 1 is converted into the communication passage 7 and the regenerating gas to burn and remove the particulate components collected by the catalyst-equipped collecting member 4. The gas is supplied to the collection member 4 through the gas supply passage 5. Furthermore, by operating the air pump 6 with the first on-off valve 9 closed and the second and third on-off valves 10 and 11 open, the air discharged from the air pump 6 is captured through the regeneration gas supply passage 5. An air supply device 12 is configured to supply air to the exhaust passage 3 on the upstream side of the collection member 4.

さらに、上記再生ガス供給通路５の連通路７と
の接続部と第３開閉弁１１との間には、通電によ
り発熱する電気発熱体１３（ヒータ）と、該電気
発熱体１３を埋め込んで密封形成された蓄熱材１
４とが配設されている。上記蓄熱材１４は例えば
融点が200〜300℃内外のリン酸塩や硝酸カリウム
と亜硝酸ナトリウムとの混合塩等の溶融塩、ある
いは融点が200℃程度のテフロン系プラスチツク、
ウツドメタル（低融点合金）等からなり、電気発
熱体１３で発生した熱エネルギを蓄熱するととも
に放熱により再生ガスを加熱するものである。そ
して、上記電気発熱体１３および蓄熱材１４によ
り、上記再生ガス（エンジン１の排気ガス）を加
熱するようにした再生ガス加熱装置１５が構成さ
れている。 Further, an electric heating element 13 (heater) that generates heat when energized is embedded between the connection part of the regeneration gas supply passage 5 with the communication passage 7 and the third on-off valve 11, and the electric heating element 13 is embedded and sealed. Formed heat storage material 1
4 are arranged. The heat storage material 14 is, for example, a molten salt such as a phosphate with a melting point of around 200 to 300°C or a mixed salt of potassium nitrate and sodium nitrite, or a Teflon plastic with a melting point of around 200°C.
It is made of wood metal (low melting point alloy), etc., and stores the thermal energy generated by the electric heating element 13 and heats the regeneration gas by heat radiation. The electric heating element 13 and the heat storage material 14 constitute a regeneration gas heating device 15 that heats the regeneration gas (exhaust gas of the engine 1).

一方、１６は上記エアポンプ６、第１〜第３開
閉弁９〜１１のアクチユエータおよび電気発熱体
１３に電力を供給するバツテリ、１７はエアポン
プ６をON−OFF制御するエアポンプ用電磁スイ
ツチ、１８は同じくエアポンプ６への通電電圧を
変えてエアポンプ６の回転数すなわちそのエア吐
出量を増減制御する変圧装置である。また、１９
は上記第１開閉弁９を開閉制御する第１開閉弁用
電磁スイツチ、２０は第２開閉弁１０を開閉制御
する第２開閉弁用電磁スイツチ、２１は第３開閉
弁１１を開閉制御する第３開閉弁用電磁スイツ
チ、２２は上記電気発熱体１３を作動制御する発
熱体用電磁スイツチであつて、以上の各電磁スイ
ツチ１７，１９〜２２は常時はOFF状態のもの
である。 On the other hand, 16 is a battery that supplies power to the air pump 6, the actuators of the first to third on-off valves 9 to 11, and the electric heating element 13, 17 is an electromagnetic switch for the air pump that controls ON/OFF of the air pump 6, and 18 is the same. This is a voltage transformation device that changes the voltage applied to the air pump 6 to increase or decrease the rotational speed of the air pump 6, that is, the amount of air discharged. Also, 19
20 is a second on-off valve electromagnetic switch that controls opening and closing of the first on-off valve 10; 21 is a second on-off valve electromagnetic switch that controls opening and closing of the third on-off valve 11; 3. An electromagnetic switch 22 for the opening/closing valve is a heating element electromagnetic switch for controlling the operation of the electric heating element 13, and each of the electromagnetic switches 17, 19 to 22 is normally in an OFF state.

また、２３は上記触媒付捕集部材４の直上流側
の排気通路３に臨設され、該排気通路３の排気ガ
ス温度T_Eを検出する排気ガス温度検出器、２４
は同じく触媒付捕集部材４の直下流側の排気通路
３に臨設され、排気ガス中の酸素濃度を検出する
排気ガスセンサとしての酸素濃度検出器、２５は
上記蓄熱材１４内に埋設され、蓄熱材温度を検出
する蓄熱材温度検出器、２６は捕集された微粒子
成分の堆積によつて捕集部材４が目詰まり状態に
なつたことを検出する目詰まり検出器である。該
目詰まり検出器２６は、捕集部材４にその軸方向
に所定の間隔をあけて埋設された２本の電極２
７，２７間の電気抵抗値を測定して、該電気抵抗
値が微粒子成分の捕集部材４への堆積に伴つてそ
の主成分たるカーボン粒子の電気伝導度の上昇に
より所定値以下に減少変化したことを判定するこ
とによつて目詰まり状態を検出するものである。 Further, reference numeral 23 denotes an exhaust gas temperature detector, which is installed in the exhaust passage 3 immediately upstream of the catalyst-equipped collection member 4 and detects the exhaust gas temperature T _E of the exhaust passage 3;
An oxygen concentration detector 25 is also installed in the exhaust passage 3 immediately downstream of the catalyst-attached collection member 4 and serves as an exhaust gas sensor for detecting the oxygen concentration in the exhaust gas. A heat storage material temperature detector 26 that detects the material temperature is a clogging detector that detects that the collection member 4 has become clogged due to the accumulation of collected particulate components. The clogging detector 26 includes two electrodes 2 embedded in the collecting member 4 at a predetermined interval in the axial direction thereof.
The electric resistance value between 7 and 27 is measured, and the electric resistance value decreases to a predetermined value or less due to an increase in the electric conductivity of carbon particles, which are the main component, as the fine particle components are deposited on the collection member 4. The clogging state is detected by determining whether the clogging has occurred.

さらに、２８は上記排気ガス温度検出器２３、
酸素濃度検出器２４、蓄熱材温度検出器２５およ
び目詰まり検出器２６からの出力を受けて上記変
圧装置１８および各電磁スイツチ１７，１９〜２
２を作動制御する制御回路であつて、該制御回路
２８はマイクロコンピユータを内蔵しており、各
検出器２３〜２６からの出力信号をマイクロコン
ピユータで処理して変圧装置１８および電磁スイ
ツチ１７，１９〜２２に所定の制御指令信号を出
力するものである。そして、この制御回路２８
は、排気ガス温度検出器２３によつて検出された
排気ガス温度T_Eが捕集部材４を加熱再生可能な
所定の再生温度T₀（例えば450℃）未満のときに
は、全開閉弁９〜１１を開作動させて排気ガスを
連通路７および再生ガス供給通路５を介して捕集
部材４上流側に導入させ、排気ガス温度T_Eが所
定の再生温度T₀以上のときは、全開閉弁９〜１
１を閉作動させて排気ガスを排気通路３（バイパ
ス通路）を介して直接捕集部材４上流側に導入さ
せるよう排気ガスの流通路を切換制御する通路切
換制御手段を構成する。さらに、排気ガス温度
T_Eが所定の再生温度T₀以上で、かつ酸素濃度検
出器２４で検出された排気ガス中の酸素濃度が所
定値以下のときに上記エア供給装置１２を作動さ
せるように制御するエア供給制御装置を構成す
る。 Furthermore, 28 is the exhaust gas temperature detector 23,
In response to the outputs from the oxygen concentration detector 24, heat storage material temperature detector 25, and clogging detector 26, the transformer 18 and each electromagnetic switch 17, 19-2
The control circuit 28 has a built-in microcomputer, and processes output signals from each of the detectors 23 to 26 with the microcomputer to control the operation of the transformer 18 and the electromagnetic switches 17 and 19. -22 outputs a predetermined control command signal. This control circuit 28
When the exhaust gas temperature T _E detected by the exhaust gas temperature detector 23 is lower than a predetermined regeneration temperature T ₀ (for example, 450° C.) at which the collection member 4 can be heated and regenerated, the full open/close valves 9 to 11 are activated. The valve is opened to introduce exhaust gas into the upstream side of the collection member 4 through the communication passage 7 and the regeneration gas supply passage 5, and when the exhaust gas temperature T _E is higher than the predetermined regeneration temperature T ₀ , the fully open/close valve is opened. 9-1
A passage switching control means is configured to switch and control the exhaust gas flow passage so as to close the exhaust gas passage 1 and directly introduce the exhaust gas into the upstream side of the collection member 4 via the exhaust passage 3 (bypass passage). Furthermore, the exhaust gas temperature
Air supply control that controls the air supply device 12 to operate when T _E is above a predetermined regeneration temperature T ₀ and the oxygen concentration in the exhaust gas detected by the oxygen concentration detector 24 is below a predetermined value. Configure the device.

次に、上記実施例の作動について説明するに、
排気ガス温度T_Eが所定温度T₀未満のときの基本
的な制御は次のように行われる。すなわち、エン
ジン１の通常の運転中は全ての開閉弁９〜１１が
閉状態に保たれ、エンジン１の排気ガスが排気通
路３を通つて直接触媒付捕集部材４に流れる。こ
のことにより、排気ガス中のカーボン等の微粒子
成分が捕集部材４に捕集され、かつ未燃ガスが捕
集部材４の触媒によつて酸化されて排気ガスが浄
化される。 Next, to explain the operation of the above embodiment,
Basic control when the exhaust gas temperature T _E is less than the predetermined temperature T ₀ is performed as follows. That is, during normal operation of the engine 1, all the on-off valves 9 to 11 are kept closed, and the exhaust gas from the engine 1 flows directly to the catalyst-equipped collection member 4 through the exhaust passage 3. As a result, particulate components such as carbon in the exhaust gas are collected by the collection member 4, and unburned gas is oxidized by the catalyst of the collection member 4, thereby purifying the exhaust gas.

そして、このような状態で一定時間が経過し、
上記捕集された微粒子成分の堆積により捕集部材
４に目詰まりが生じて電極２７，２７間の電気抵
抗値が所定値以上に減少すると、そのことを目詰
まり検出器２６が検出して制御回路２８に目詰ま
り信号を出力し、この目詰まり信号を受けた制御
回路２８の作動により捕集部材４の再生を行うべ
く電気発熱体１３にバツテリ１６の電圧が通電さ
れる。この通電により発熱体１３が発熱してその
周囲の蓄熱材１４を加熱し、発熱体１３で発生し
た熱エネルギが蓄熱材１４に蓄熱される。 Then, a certain amount of time passes in this state,
When the collecting member 4 is clogged due to the accumulation of the collected particulate components and the electrical resistance value between the electrodes 27 and 27 decreases to a predetermined value or more, the clogging detector 26 detects this and controls the A clogging signal is output to the circuit 28, and the voltage of the battery 16 is applied to the electric heating element 13 in order to regenerate the collection member 4 by the operation of the control circuit 28 which receives this clogging signal. This energization causes the heating element 13 to generate heat and heat the surrounding heat storage material 14, and the thermal energy generated by the heating element 13 is stored in the heat storage material 14.

このような蓄熱材１４への熱エネルギの蓄熱に
より蓄熱材１４の温度が所定温度以上に上昇する
と、制御回路２８の作動により全開閉弁９〜１１
が開かれ、この動作によりエンジン１の排気ガス
が連通路７および再生ガス供給通路５を通つて捕
集部材４に流れ、該排気ガスは上記再生ガス供給
通路５を通る間にその途中の蓄熱状態にある高温
の蓄熱材１４との効率良い熱交換作用により捕集
部材４を再生できる高温の再生温度T₀（約450℃
以上）まで素早く加熱されて再生ガスとなる。こ
の高温の再生ガスの捕集部材４への流入により該
捕集部材４に捕集されていた微粒子成分は加熱さ
れてその燃焼が始まる。尚、この間、上記再生ガ
ス（排気ガス）中の酸素濃度が酸素濃度検出器２
４によつて検出され、該再生ガス中の酸素濃度が
設定濃度以下であるときには捕集部材４での微粒
子成分の燃焼に必要な酸素量が不足している状態
とみて、制御回路２８の作動によりエアポンプ６
が作動して再生ガス中にエアが補充される。 When the temperature of the heat storage material 14 rises above a predetermined temperature due to the storage of thermal energy in the heat storage material 14, the control circuit 28 operates to close the full open/close valves 9 to 11.
is opened, and as a result of this operation, the exhaust gas of the engine 1 flows through the communication path 7 and the regeneration gas supply path 5 to the collection member 4, and while the exhaust gas passes through the regeneration gas supply path 5, it collects heat on the way. The high regeneration temperature T ₀ (approx. 450°C) allows the collection member 4 to be regenerated through efficient heat exchange with the high temperature heat storage material 14 in
above) and becomes regeneration gas. As this high-temperature regeneration gas flows into the collection member 4, the particulate components collected on the collection member 4 are heated and combustion begins. During this time, the oxygen concentration in the regeneration gas (exhaust gas) is detected by the oxygen concentration detector 2.
4, and when the oxygen concentration in the regeneration gas is below the set concentration, it is assumed that the amount of oxygen necessary for combustion of the particulate components in the collection member 4 is insufficient, and the control circuit 28 is activated. Air pump 6
is activated and air is replenished into the regeneration gas.

そして、一定時間経過後に上記微粒子成分の燃
焼除去により捕集部材４の目詰まりが解消されて
電極２７，２７間の抵抗値がもとの大きさに戻る
と電気発熱体１３への通電が停止され、以上によ
り捕集部材４の再生が完了して以後は上記と同様
の制御が繰り返される。 Then, after a certain period of time has elapsed, when the clogging of the collection member 4 is resolved by combustion and removal of the particulate components and the resistance value between the electrodes 27 and 27 returns to its original value, the electricity supply to the electric heating element 13 is stopped. After the regeneration of the collection member 4 is completed, the same control as described above is repeated.

また、以上に説明した基本的な制御が行われて
いる間に、エンジン１の排気ガス温度T_Eが所定
温度T₀以上に上昇すると、他の制御に優先して
排気ガス自体の熱エネルギによる捕集部材４の加
熱再生が行われる。その制御を第２図に示す制御
フロチヤートを参考にして説明すると、先ず、ス
タート後の最初のステツプS₁において排気ガス温
度検出器２３による排気ガス温度T_Eの検出が行
われ、次いでステツプS₂において該排気ガス温度
T_Eが捕集部材４を加熱再生可能な再生温度T₀（Ｔ
≒450℃）以上に達したか否かの判定が行われ、
この判定がT_E＜T₀によりNOであるときには上
記ステツプS₁，S₂が繰り返される。つまり上述の
基本の制御が実行される。 Furthermore, while the basic control described above is being performed, if the exhaust gas temperature T _E of the engine 1 rises above the predetermined temperature T ₀ , the thermal energy of the exhaust gas itself will be used in priority over other controls. The collection member 4 is heated and regenerated. The control will be explained with reference to the control flowchart shown in FIG. 2. First, in the first step _S1 after the start, the exhaust gas temperature T _E is detected by the exhaust gas temperature detector 23, and then in step _S2 . The exhaust gas temperature at
The regeneration temperature T ₀ ( _T
A determination is made as to whether the temperature has reached ≒450℃ or higher.
If this determination is NO because T _E <T ₀ , the above steps S ₁ and S ₂ are repeated. In other words, the basic control described above is executed.

一方、上記判定がT_E≧T₀によりYESになると
ステツプS₃に移り、全開閉弁９〜１１が閉じられ
て高温の排気ガスが排気通路３を通つて直接捕集
部材４側に流れ、この高温の排気ガスの流入によ
りその時点までに捕集部材４に捕集されていた微
粒子成分が加熱されて燃焼除去され、捕集部材４
が再生される。この後、ステツプS₄において前述
の如く酸素濃度検出器２４により検出した排気ガ
ス中の酸素濃度が設定値以下であるか否かが判定
され、この判定がNOであるとき、すなわち排気
ガス中の酸素が捕集部材４の再生状態で微粒子成
分の燃焼に費やされた後でも設定濃度よりも多く
残存しているときには、エンジン１からの排気ガ
ス中に微粒子成分の燃焼のための酸素が充足して
いる状態とみてそのままステツプS₁に戻り、捕集
部材４の加熱再生が継続される。一方、上記ステ
ツプS₄での判定がYESであるとき、すなわち捕
集部材４通過後の排気ガス中の酸素濃度が設定濃
度以下であるときには、エンジン１からの排気ガ
ス中に微粒子成分を良好に燃焼させるだけの酸化
反応のための酸素量が不足している状態とみて、
次のステツプS₅において排気ガス中の酸素不足を
補充してその濃度を設定値に収めるべく、第１開
閉弁９が閉じかつ第３開閉弁１１が開いた状態で
第２開閉弁１０の開度が制御されて捕集部材４に
至る排気ガス流量が制御され、かつエアポンプ６
への通電電圧の制御によりそのエア吐出量が調整
される。このことにより、捕集部材４に捕集され
ている微粒子成分が十分な酸素のもとで確実に燃
焼して除去される。 On the other hand, if the above judgment becomes YES due to T _E ≧ T ₀ , the process moves to step S ₃ , where the full open/close valves 9 to 11 are closed and the high temperature exhaust gas flows directly to the collection member 4 side through the exhaust passage 3. Due to the inflow of this high-temperature exhaust gas, the particulate components that had been collected by the collection member 4 up to that point are heated and burned and removed, and the collection member 4
is played. After that, in step _S4 , it is determined whether the oxygen concentration in the exhaust gas detected by the oxygen concentration detector 24 is below the set value as described above, and when this determination is NO, that is, the oxygen concentration in the exhaust gas is When more oxygen remains than the set concentration even after the collection member 4 is consumed in the combustion of the particulate components in the regenerated state, the exhaust gas from the engine 1 is filled with oxygen for the combustion of the particulate components. Assuming that this is the case, the process returns to step _S1 and the heating regeneration of the collection member 4 is continued. On the other hand, when the determination in step S ₄ is YES, that is, when the oxygen concentration in the exhaust gas after passing through the collection member 4 is below the set concentration, fine particle components are not properly contained in the exhaust gas from the engine 1. It is assumed that there is not enough oxygen for the oxidation reaction to cause combustion.
In the next step _S5 , the second on-off valve 10 is opened while the first on-off valve 9 is closed and the third on-off valve 11 is open, in order to replenish the oxygen deficiency in the exhaust gas and bring the concentration within the set value. The air pump 6
The amount of air discharged is adjusted by controlling the energizing voltage. This ensures that the particulate components collected in the collection member 4 are burned and removed in sufficient oxygen.

この後、上記捕集部材４の再生が終了すると、
エアポンプ６〜の通電が停止され、かつ全開閉弁
９〜１１が閉じられて上記ステツプS₁に戻り、以
後は排気ガス温度T_Eが再生温度T₀以上に達する
毎に上記と同様の制御が繰り返される。 After this, when the regeneration of the collection member 4 is completed,
The power supply to the air pumps 6 to 6 is stopped, and the full open/close valves 9 to 11 are closed to return to step _S1 , and from then on, the same control as above is performed every time the exhaust gas temperature T _E reaches the regeneration temperature _T0 or higher. Repeated.

したがつて、本実施例では、触媒付捕集部材４
の再生の基本的な制御を行う場合、その再生準備
行程で電気発熱体１３からの熱エネルギを蓄熱材
１４に徐々に蓄熱しておき、再生時にはこの蓄熱
材１４で蓄熱された熱エネルギによつて排気ガス
（再生ガス）を再生温度T₀まで効率良く加熱昇温
させるため、再生時に単に電気発熱体のみで再生
ガスを加熱する加熱システムに比べて電気発熱体
１３にて賄う熱エネルギが少なくて済み、よつて
電気発熱体１３の発熱容量およびバツテリ１６の
電気容量を小さく設定することができる。 Therefore, in this embodiment, the catalyst-equipped collection member 4
When performing basic control of regeneration, the thermal energy from the electric heating element 13 is gradually stored in the heat storage material 14 during the regeneration preparation process, and the thermal energy stored in the heat storage material 14 is used during regeneration. In order to efficiently heat the exhaust gas (regeneration gas) to the regeneration temperature _T0 , the electric heating element 13 requires less heat energy during regeneration compared to a heating system that heats the regeneration gas only with an electric heating element. Therefore, the heat generating capacity of the electric heating element 13 and the electric capacity of the battery 16 can be set small.

また、このように電気発熱体１３の発熱容量お
よびバツテリ１６の電気容量が小さくなると、そ
の小さくなつた分だけ捕集部材４の再生準備時
間、つまり蓄熱材１４が所定温度以上に上昇する
までの時間が長くなり、その再生準備時間の経過
中にエンジン１の運転を停止するという短時間運
転パターンが繰り返されたときには、上記基本的
な制御によつては蓄熱材１４で蓄熱する熱エネル
ギが不足して捕集部材４の再生を良好に行うこと
が困難になる。しかし、本実施例では、上記捕集
部材４を再生するための基本的な制御が行われて
いる間に、排気ガス温度T_Eが再生温度T₀以上に
上昇すると、他の制御に優先してこの高温の排気
ガスの熱エネルギそのもので捕集部材４を本来の
目詰まり検出を待たずに再生するため、その間に
蓄熱材１４の蓄熱が排気ガスにより奪われるのを
防止しながら電気発熱体１３により該蓄熱材１４
に十分に蓄熱することができる。また、その時の
排気ガス中の酸素濃度が所定値以下のときには、
上記所定温度以上の排気ガスに加えてエアを供給
して触媒付捕集部材４の酸化反応を促進したので
再生を良好に行うことができる。よつて、電気発
熱体１３やバツテリ１６の容量が小さくても、か
つ短時間のエンジン１の運転を繰返しても、捕集
部材４を良好に再生することが可能である。ま
た、このことにより電気発熱体１３による消費電
力を低減し、かつ捕集部材４の再生インターバル
を安全側に設定することができる。 In addition, when the heat generation capacity of the electric heating element 13 and the electric capacity of the battery 16 decrease in this way, the regeneration preparation time of the collection member 4, that is, the time required for the heat storage material 14 to rise above a predetermined temperature, is increased by the amount corresponding to the decrease. When the time becomes long and the short-time operation pattern of stopping the operation of the engine 1 during the elapse of the regeneration preparation time is repeated, the thermal energy stored in the heat storage material 14 is insufficient due to the above-mentioned basic control. This makes it difficult to properly regenerate the collection member 4. However, in this embodiment, if the exhaust gas temperature T _E rises above the regeneration temperature T ₀ while the basic control for regenerating the collection member 4 is being performed, other controls are prioritized. In order to regenerate the collection member 4 without waiting for the original clogging detection using the thermal energy of the high-temperature exhaust gas itself, the electric heating element 13, the heat storage material 14
can store sufficient heat. Also, if the oxygen concentration in the exhaust gas at that time is below a predetermined value,
Since air is supplied in addition to the exhaust gas having a temperature above the predetermined temperature to promote the oxidation reaction of the catalyst-equipped collection member 4, regeneration can be performed satisfactorily. Therefore, even if the capacity of the electric heating element 13 and battery 16 is small, and even if the engine 1 is repeatedly operated for a short period of time, it is possible to regenerate the collection member 4 favorably. Furthermore, this allows the power consumption by the electric heating element 13 to be reduced and the regeneration interval of the collection member 4 to be set on the safe side.

尚、上記実施例では、電極２７，２７間の電気
抵抗値の減少変化により捕集部材４の目詰まりを
検出してその再生を行うようにしたが、本考案
は、排気通路の捕集部材上下流側間の圧力差をみ
て該圧力差が増大したときに捕集部材を目詰まり
状態と判定するようにした排気浄化装置や、燃料
消費量、エンジンの運転時間等を累積してその値
が一定値を越えると定期的に捕集部材の再生を行
うようにした排気浄化装置等に対しても適用する
ことができるのは勿論のことである。 In the above embodiment, the clogging of the collection member 4 is detected and regenerated by the decreasing change in the electrical resistance value between the electrodes 27, 27, but the present invention An exhaust purification device that looks at the pressure difference between upstream and downstream sides and determines that the collection member is clogged when the pressure difference increases, and the cumulative value of fuel consumption, engine operating time, etc. Of course, the present invention can also be applied to an exhaust gas purification device or the like in which the collection member is periodically regenerated when the amount exceeds a certain value.

[Brief explanation of the drawing]

図面は本考案の実施例を示すもので、第１図は
全体構成図、第２図は制御システムの一部を示す
フローチヤート図である。１……エンジン、３……排気通路、４……触媒
付捕集部材、５……再生ガス供給通路、６……エ
アポンプ、７……連通路、９……第１開閉弁、１
０……第２開閉弁、１１……第３開閉弁、１２…
…エア供給装置、１３……電気発熱体、１４……
蓄熱材、１５……再生ガス加熱装置、２３……排
気ガス温度検出器、２４……酸素濃度検出器、２
５……蓄熱材温度検出器、２６……目詰まり検出
器、２８……制御回路。 The drawings show an embodiment of the present invention; FIG. 1 is an overall configuration diagram, and FIG. 2 is a flowchart showing a part of the control system. DESCRIPTION OF SYMBOLS 1...Engine, 3...Exhaust passage, 4...Collection member with catalyst, 5...Regeneration gas supply passage, 6...Air pump, 7...Communication passage, 9...First on-off valve, 1
0...Second on-off valve, 11...Third on-off valve, 12...
...Air supply device, 13...Electric heating element, 14...
Heat storage material, 15...Regeneration gas heating device, 23...Exhaust gas temperature detector, 24...Oxygen concentration detector, 2
5... Heat storage material temperature detector, 26... Clogging detector, 28... Control circuit.

Claims

[Scope of utility model registration request]

A regeneration gas heating device that provides a catalyst-equipped collection member for collecting particulate components such as carbon particles in the exhaust passage, and heats regeneration gas to burn and remove the particulate components collected by the catalyst-equipped collection member. An exhaust gas purification device for a diesel engine, wherein the regeneration gas heating device includes an electric heating element and a heat storage material that stores thermal energy from the electric heating element and heats the regeneration gas by heat radiation. , further comprising: a bypass passage that is an exhaust passage upstream of the collection member and bypasses the regeneration gas heating device; and an exhaust gas temperature detector that detects the temperature of exhaust gas in the exhaust passage upstream of the collection member. , an exhaust gas sensor that detects the oxygen concentration in the exhaust gas, an air supply device that supplies air to the exhaust passage on the upstream side of the collection member, and an exhaust gas temperature that is determined by receiving the output of the exhaust gas temperature detector. When the exhaust gas temperature is below a predetermined temperature, the exhaust gas is introduced into the upstream side of the collection member through the exhaust passage interposed by the regeneration gas heating device, and when the exhaust gas temperature is above a predetermined temperature, the exhaust gas is collected through the bypass passage. passage switching control means for switching and controlling the flow passage of exhaust gas so as to introduce the exhaust gas into the upstream side of the member; 1. An exhaust purification device for a diesel engine, comprising: an air supply control device that controls the air supply device to operate when the oxygen concentration in the gas is below a set value.