JP2020067055A - Reducer supply device - Google Patents

Reducer supply device Download PDF

Info

Publication number
JP2020067055A
JP2020067055A JP2018201437A JP2018201437A JP2020067055A JP 2020067055 A JP2020067055 A JP 2020067055A JP 2018201437 A JP2018201437 A JP 2018201437A JP 2018201437 A JP2018201437 A JP 2018201437A JP 2020067055 A JP2020067055 A JP 2020067055A
Authority
JP
Japan
Prior art keywords
reducing agent
passage
agent supply
reducer
liquid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2018201437A
Other languages
Japanese (ja)
Other versions
JP7203562B2 (en
Inventor
敦史 徳永
Atsushi Tokunaga
敦史 徳永
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Priority to JP2018201437A priority Critical patent/JP7203562B2/en
Publication of JP2020067055A publication Critical patent/JP2020067055A/en
Application granted granted Critical
Publication of JP7203562B2 publication Critical patent/JP7203562B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Landscapes

  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

To provide a reducer supply device capable of reducing a residual amount of a liquid reducer after recovering the liquid reducer in the reducer supply device.SOLUTION: A reducer supply device (30) includes a reducer supply passage (57) connecting a pump (41) and a reducer injection valve (31), and a return passage (59) branched from the reducer supply passage (57) for returning a part of a liquid reducer pressure-fed by the pump (41) to the tank (50), executes a control for supplying the liquid reducer to a reducer injection valve (31) side in operating an internal combustion engine (5), and executes a control for sucking back the liquid reducer to recover the same into the tank (50) in stopping the internal combustion engine (5). The reducer supply device includes a flow channel area variable mechanism (80) for changing a flow channel area by a pressure generated in the reducer supply passage (57), on the way of the return passage (59), and the flow channel area variable mechanism (80) reduces a flow channel area in executing the control to recover the liquid reducer, in comparison with a time in executing the control to supply the liquid reducer, to make the liquid reducer pass therethrough.SELECTED DRAWING: Figure 3

Description

本発明は、内燃機関の排気通路に液体還元剤を供給するための還元剤供給装置に関する。   The present invention relates to a reducing agent supply device for supplying a liquid reducing agent to an exhaust passage of an internal combustion engine.

車両等に搭載された内燃機関から排出される排気ガスを浄化する排気浄化装置の一態様として、排気ガス中の窒素酸化物（ＮＯX）の還元反応を促進する選択還元触媒と、選択還元触媒よりも上流側で排気通路内に液体還元剤を供給する還元剤供給装置とを備えた排気浄化装置がある。還元剤供給装置として、タンク内の液体還元剤を吸い上げて圧送するポンプと、ポンプにより圧送される液体還元剤を排気通路内に噴射する還元剤噴射弁とを備えた装置が知られている。 A selective reduction catalyst that promotes a reduction reaction of nitrogen oxides (NO x ) in exhaust gas, and a selective reduction catalyst, as an aspect of an exhaust purification device that purifies exhaust gas emitted from an internal combustion engine mounted on a vehicle or the like There is an exhaust gas purification device that includes a reducing agent supply device that supplies a liquid reducing agent into the exhaust passage on the upstream side of the exhaust gas. As a reducing agent supply device, there is known an apparatus including a pump that sucks up the liquid reducing agent in a tank and pressure-feeds it, and a reducing agent injection valve that injects the liquid reducing agent pressure-fed by the pump into the exhaust passage.

このような還元剤供給装置において、目標噴射量相当の液体還元剤を精度よく噴射するために、ポンプによって圧送される液体還元剤の一部を、還元剤供給通路から分岐するリターン通路を介してタンクに戻しながら還元剤供給通路内の圧力を一定に保ち、還元剤噴射弁の開閉を制御することが行われている。   In such a reducing agent supply device, in order to accurately inject a liquid reducing agent equivalent to the target injection amount, a part of the liquid reducing agent pumped by the pump is passed through a return passage branched from the reducing agent supply passage. While returning to the tank, the pressure in the reducing agent supply passage is kept constant and the opening / closing of the reducing agent injection valve is controlled.

ここで、内燃機関の停止後においても還元剤噴射弁や還元剤供給通路内に液体還元剤が残留していると、残留する尿素水溶液が凍結し、体積が膨張することによって還元剤噴射弁等が破損するおそれがある。このため、内燃機関の停止時には、還元剤供給装置内に残留する液体還元剤をタンク内に回収する制御が実行される。液体還元剤をタンク内に回収する方法としては、ポンプを逆回転させる方法や、液体還元剤の流れる方向を還元剤噴射弁側からタンク側に切り換える方法が知られている（例えば、特許文献１及び２を参照）。   Here, if the liquid reducing agent remains in the reducing agent injection valve or the reducing agent supply passage even after the internal combustion engine is stopped, the remaining urea aqueous solution freezes and the volume expands to reduce the reducing agent injection valve, etc. May be damaged. Therefore, when the internal combustion engine is stopped, control is performed to recover the liquid reducing agent remaining in the reducing agent supply device into the tank. Known methods for collecting the liquid reducing agent in the tank include a method of rotating the pump in the reverse direction and a method of switching the flowing direction of the liquid reducing agent from the reducing agent injection valve side to the tank side (for example, Patent Document 1). And 2).

特開２０１０−１８５３３４号公報JP, 2010-185334, A 特開２０１０−０２４８９６号公報JP, 2010-024896, A

ここで、液体還元剤を回収する際、還元剤供給通路内の液体還元剤の吸い戻し量は、主として還元剤供給通路側の容量、還元剤噴射弁の噴射孔の面積の和、リターン通路側の容量、リターン通路の最小流路面積、及びポンプの駆動により生じる負圧により決定される。還元剤供給通路の長さは車両ごとに様々であるため、還元剤供給通路側の容量は車両ごとに異なる。リターン通路側の液体還元剤が還元剤供給通路側の液体還元剤よりも先に吸い戻された場合、その後は、リターン通路側にはタンク内の空気が吸引される。そうすると、液体還元剤に比べて空気の方が吸引されやすいために、還元剤供給通路側の液体還元剤よりも空気が優先的に吸い戻されてしまい、還元剤供給通路側に液体還元剤が残りやすくなる。   Here, when recovering the liquid reducing agent, the sucking back amount of the liquid reducing agent in the reducing agent supply passage is mainly the sum of the capacity of the reducing agent supply passage side, the area of the injection holes of the reducing agent injection valve, and the return passage side. Capacity, the minimum flow passage area of the return passage, and the negative pressure generated by driving the pump. Since the length of the reducing agent supply passage varies from vehicle to vehicle, the capacity on the reducing agent supply passage side differs from vehicle to vehicle. When the liquid reducing agent on the return passage side is sucked back before the liquid reducing agent on the reducing agent supply passage side, the air in the tank is sucked on the return passage side thereafter. Then, since the air is more easily sucked than the liquid reducing agent, the air is preferentially sucked back over the liquid reducing agent on the reducing agent supply passage side, and the liquid reducing agent is absorbed on the reducing agent supply passage side. It becomes easier to remain.

本発明は、上記問題に鑑みてなされたものであり、還元剤供給装置内の液体還元剤の回収後における液体還元剤の残留量を低減可能な還元剤供給装置を提供することを目的とする。   The present invention has been made in view of the above problems, and an object of the present invention is to provide a reducing agent supply device capable of reducing the residual amount of the liquid reducing agent after the recovery of the liquid reducing agent in the reducing agent supply device. .

上記課題を解決するために、本発明のある観点によれば、タンク内の液体還元剤を吸い上げて圧送するポンプと、ポンプにより圧送される液体還元剤を内燃機関の排気通路に噴射する還元剤噴射弁と、ポンプと還元剤噴射弁とを接続する還元剤供給通路と、ポンプにより圧送される液体還元剤の一部をタンクに戻すために還元剤供給通路から分岐して設けられたリターン通路と、を備え、内燃機関の運転時には液体還元剤を還元剤噴射弁側に供給する制御が実行され、内燃機関の停止時には液体還元剤を吸い戻してタンクに回収する制御が実行される還元剤供給装置において、リターン通路の途中に、還元剤供給通路内に生じる圧力によって流路面積が変化する流路面積可変機構を備え、流路面積可変機構は、液体還元剤を回収する制御の実行時に、液体還元剤を供給する制御の実行時に比べて流路面積を小さくして、液体還元剤を通過させる還元剤供給装置が提供される。   In order to solve the above-mentioned problems, according to an aspect of the present invention, a pump that sucks up a liquid reducing agent in a tank and pressure-feeds it, and a reducing agent that injects the liquid reducing agent pumped by the pump into an exhaust passage of an internal combustion engine. An injection valve, a reducing agent supply passage connecting the pump and the reducing agent injection valve, and a return passage branched from the reducing agent supply passage for returning a part of the liquid reducing agent pumped by the pump to the tank. And a control for supplying the liquid reducing agent to the reducing agent injection valve side when the internal combustion engine is operating, and a control for sucking back the liquid reducing agent and collecting it in the tank when the internal combustion engine is stopped. In the supply device, a flow passage area variable mechanism that changes the flow passage area due to the pressure generated in the reducing agent supply passage is provided in the middle of the return passage, and the flow passage area variable mechanism implements the control of recovering the liquid reducing agent. Sometimes, the flow path area than that in the execution of the control for supplying the liquid reducing agent is made smaller, the reducing agent supply device for passing the liquid reducing agent is provided.

以上説明したように本発明によれば、還元剤供給装置内の液体還元剤の回収後における液体還元剤の残留量を低減することができる。   As described above, according to the present invention, it is possible to reduce the residual amount of the liquid reducing agent after the liquid reducing agent in the reducing agent supply device is recovered.

本発明の実施の形態に係る還元剤供給装置を適用した尿素ＳＣＲシステムの構成例を示す模式図である。It is a schematic diagram which shows the structural example of the urea SCR system to which the reducing agent supply apparatus which concerns on embodiment of this invention is applied. 同実施形態に係るオリフィス部の構成例を示す説明図である。It is explanatory drawing which shows the structural example of the orifice part which concerns on the same embodiment. 同実施形態に係るオリフィス部の動作を示す説明図である。It is explanatory drawing which shows operation | movement of the orifice part which concerns on the same embodiment. 還元剤供給装置の流路構成を示す模式図である。It is a schematic diagram which shows the flow path structure of a reducing agent supply apparatus. 調節部材を用いたオリフィス部を示す説明図である。It is explanatory drawing which shows the orifice part which used the adjustment member. オリフィス部の変形例を示す説明図である。It is explanatory drawing which shows the modification of an orifice part. オリフィス部の変形例を示す説明図である。It is explanatory drawing which shows the modification of an orifice part.

以下に添付図面を参照しながら、本発明の好適な実施の形態について詳細に説明する。なお、本明細書及び図面において、実質的に同一の機能構成を有する構成要素については、同一の符号を付することにより重複説明を省略する。   Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, constituent elements having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

＜１．還元剤供給装置の全体構成＞
まず、本実施形態に係る還元剤供給装置を適用可能な尿素ＳＣＲシステムの全体構成の一例について説明する。図１は、尿素ＳＣＲシステム１０の構成例を示す模式図である。 <1. Overall structure of reducing agent supply device>
First, an example of the overall configuration of a urea SCR system to which the reducing agent supply device according to the present embodiment can be applied will be described. FIG. 1 is a schematic diagram showing a configuration example of the urea SCR system 10.

尿素ＳＣＲシステム１０は、ディーゼルエンジン等に代表される内燃機関５の排気系に接続された排気管１１の途中に配設された選択還元触媒１３と、選択還元触媒１３よりも上流側で排気管１１内に尿素水溶液を噴射する還元剤供給装置３０とを備える。尿素ＳＣＲシステム１０は、例えば自動車等の車両に搭載され、内燃機関５から排出される排気中のＮＯXを、尿素水溶液を用いて還元することにより排気を浄化するシステムである。尿素水溶液としては、例えば凍結温度が最も低い、約３２．５％濃度の尿素水溶液が用いられる。この場合の凍結温度は、約−１１℃である。 The urea SCR system 10 includes a selective reduction catalyst 13 arranged in the middle of an exhaust pipe 11 connected to an exhaust system of an internal combustion engine 5 typified by a diesel engine, and an exhaust pipe upstream of the selective reduction catalyst 13. 11 and a reducing agent supply device 30 for injecting a urea aqueous solution. The urea SCR system 10 is mounted on, for example, a vehicle such as an automobile, and is a system that purifies exhaust gas by reducing NO x in the exhaust gas discharged from the internal combustion engine 5 using an aqueous urea solution. As the urea aqueous solution, for example, a urea aqueous solution having the lowest freezing temperature and a concentration of about 32.5% is used. The freezing temperature in this case is about -11 ° C.

選択還元触媒１３は、内燃機関５の排気中に含まれるＮＯXを選択的に還元する機能を有する。例えば、選択還元触媒１３は、還元剤供給装置３０により供給される尿素水溶液が分解して生成されるアンモニアを吸着する。そして、選択還元触媒１３に流入する排気中のＮＯXは、アンモニアと還元反応することによって分解される。かかる選択還元触媒１３は、温度が活性温度を超える状態でＮＯXの還元効率が上昇し、温度が高いほどアンモニアの吸着可能量が減少する特性を有する。また、選択還元触媒１３は、吸着可能量に対する実際のアンモニアの吸着率が高いほど、ＮＯXの還元効率が高くなる特性を有する。 The selective reduction catalyst 13 has a function of selectively reducing NO X contained in the exhaust gas of the internal combustion engine 5. For example, the selective reduction catalyst 13 adsorbs ammonia produced by decomposition of the urea aqueous solution supplied by the reducing agent supply device 30. Then, NO X in the exhaust gas flowing into the selective reduction catalyst 13 is decomposed by performing a reduction reaction with ammonia. The selective reduction catalyst 13 has a characteristic that the NO x reduction efficiency increases when the temperature exceeds the activation temperature, and the adsorbable amount of ammonia decreases as the temperature increases. Further, the selective reduction catalyst 13 has a characteristic that the higher the actual adsorption rate of ammonia with respect to the adsorbable amount, the higher the NO x reduction efficiency.

還元剤供給装置３０は、選択還元触媒１３よりも上流側の排気管１１内に尿素水溶液を供給する。尿素水溶液の供給量は、排気中に含まれるＮＯXの濃度及び選択還元触媒１３におけるアンモニアの吸着可能量等に基づいて、選択還元触媒１３の下流側に、ＮＯXあるいはアンモニアが流出しないように制御装置１００によって制御される。 The reducing agent supply device 30 supplies the urea aqueous solution into the exhaust pipe 11 on the upstream side of the selective reduction catalyst 13. The supply amount of the urea aqueous solution is adjusted so that NO X or ammonia does not flow out to the downstream side of the selective reduction catalyst 13 based on the concentration of NO X contained in the exhaust gas, the adsorbable amount of ammonia in the selective reduction catalyst 13, and the like. It is controlled by the control device 100.

この他、排気管１１には、排気温度センサ２１及びＮＯXセンサ２３等の各種センサが設けられてもよい。これらのセンサは、それぞれ、排気温度又はＮＯX濃度等の検出に用いられる。また、排気温度センサ２１によって検出される排気温度は、選択還元触媒１３の温度推定に用いられてもよい。 In addition, the exhaust pipe 11, the various sensors may be provided, such as exhaust gas temperature sensor 21 and the NO X sensor 23. These sensors, respectively, are used for the detection of such exhaust gas temperature or the NO X concentration. The exhaust gas temperature detected by the exhaust gas temperature sensor 21 may be used for estimating the temperature of the selective reduction catalyst 13.

＜２．還元剤供給装置＞
次に、本実施形態に係る還元剤供給装置３０の構成例について詳細に説明する。
還元剤供給装置３０は、尿素水溶液を貯蔵する貯蔵タンク５０と、尿素水溶液を圧送するポンプ４１と、流路切換弁３５と、選択還元触媒１３よりも上流側の排気管１１に固定された還元剤噴射弁３１とを備える。ポンプ４１及び還元剤噴射弁３１は、マイクロコンピュータ等を備えて構成される制御装置１００によって駆動制御される。貯蔵タンク５０には、尿素水溶液の温度を検出する温度センサ５１が設けられる。 <2. Reductant supply device>
Next, a configuration example of the reducing agent supply device 30 according to the present embodiment will be described in detail.
The reducing agent supply device 30 includes a storage tank 50 that stores an aqueous urea solution, a pump 41 that pumps the aqueous urea solution, a flow path switching valve 35, and a reduction fixed to the exhaust pipe 11 upstream of the selective reduction catalyst 13. The agent injection valve 31 is provided. The pump 41 and the reducing agent injection valve 31 are drive-controlled by the control device 100 including a microcomputer and the like. The storage tank 50 is provided with a temperature sensor 51 that detects the temperature of the urea aqueous solution.

ポンプ４１は、第１の還元剤供給通路５８を介して、尿素水溶液を貯留する貯蔵タンク５０と接続される。また、ポンプ４１は、第２の還元剤供給通路５７を介して還元剤噴射弁３１と接続される。第２の還元剤供給通路５７には、還元剤噴射弁３１へ供給される尿素水溶液の圧力を検出する圧力センサ４３が設けられる。また、第２の還元剤供給通路５７には、他端が貯蔵タンク５０に接続されたリターン通路５９が接続されている。   The pump 41 is connected to the storage tank 50 that stores the urea aqueous solution, via the first reducing agent supply passage 58. The pump 41 is also connected to the reducing agent injection valve 31 via the second reducing agent supply passage 57. The second reducing agent supply passage 57 is provided with a pressure sensor 43 that detects the pressure of the urea aqueous solution supplied to the reducing agent injection valve 31. A return passage 59, the other end of which is connected to the storage tank 50, is connected to the second reducing agent supply passage 57.

ポンプ４１としては、例えば電動式のダイヤフラムポンプやモータポンプが用いられる。制御装置１００は、第２の還元剤供給通路５７内の圧力、すなわち、還元剤噴射弁３１へ供給される尿素水溶液の圧力が所定の目標値で維持されるように、ポンプ４１の出力を制御する。例えば、制御装置１００は、第２の還元剤供給通路５７に設けられた圧力センサ４３により検出される圧力と目標値との差分に基づいて、ポンプ４１の出力をフィードバック制御する。   As the pump 41, for example, an electric diaphragm pump or a motor pump is used. The control device 100 controls the output of the pump 41 so that the pressure in the second reducing agent supply passage 57, that is, the pressure of the urea aqueous solution supplied to the reducing agent injection valve 31 is maintained at a predetermined target value. To do. For example, the control device 100 feedback-controls the output of the pump 41 based on the difference between the pressure detected by the pressure sensor 43 provided in the second reducing agent supply passage 57 and the target value.

リターン通路５９には、内部に絞り通路が形成されたオリフィス部７０が備えられている。リターン通路５９を介して貯蔵タンク５０に戻される尿素水溶液の流量が大きいと、ポンプ４１の要求出力が大きくなる。このため、絞り通路を有するオリフィス部７０をリターン通路５９に設け、第２の還元剤供給通路５７内の圧力を保持しやすくすることによって、ポンプ４１の要求出力が過度に大きくならないようになっている。また、ポンプ４１の要求出力が過度に大きくならないことにより、第２の還元剤供給通路５７内の圧力脈動が小さく抑えられる。   The return passage 59 is provided with an orifice portion 70 in which a throttle passage is formed. When the flow rate of the urea aqueous solution returned to the storage tank 50 via the return passage 59 is large, the required output of the pump 41 becomes large. Therefore, the orifice 70 having the throttle passage is provided in the return passage 59 so that the pressure in the second reducing agent supply passage 57 can be easily maintained, so that the required output of the pump 41 does not become excessively large. There is. Further, since the required output of the pump 41 does not become excessively large, the pressure pulsation in the second reducing agent supply passage 57 can be suppressed to be small.

流路切換弁３５は、ポンプ４１によって圧送される尿素水溶液の流れる方向を切り換える。流路切換弁３５は、例えば電磁弁を用いて構成され、制御装置１００によって駆動される。本実施形態では、流路切換弁３５を用いて、ポンプ４１の吸入側と第１の還元剤供給通路５８、及び、ポンプ４１の吐出側と第２の還元剤供給通路５７をそれぞれ接続する第１の状態と、ポンプ４１の吐出側と第１の還元剤供給通路５８、及び、ポンプ４１の吸入側と第２の還元剤供給通路５７をそれぞれ接続する第２の状態とに切り換えられる。   The flow path switching valve 35 switches the flowing direction of the urea aqueous solution pumped by the pump 41. The flow path switching valve 35 is configured by using, for example, an electromagnetic valve, and is driven by the control device 100. In the present embodiment, the flow path switching valve 35 is used to connect the suction side of the pump 41 and the first reducing agent supply passage 58, and the discharge side of the pump 41 and the second reducing agent supply passage 57, respectively. The first state is switched to the second state in which the discharge side of the pump 41 is connected to the first reducing agent supply passage 58, and the suction side of the pump 41 is connected to the second reducing agent supply passage 57.

排気管１１内への尿素水溶液の噴射制御を行う場合には、尿素水溶液が貯蔵タンク５０側から還元剤噴射弁３１側へ流れるように、流路切換弁３５が第１の状態に保持される。また、還元剤供給装置３０内の尿素水溶液を貯蔵タンク５０に回収する場合には、尿素水溶液が還元剤噴射弁３１側から貯蔵タンク５０側へ流れるように、流路切換弁３５が第２の状態に保持される。   When performing the injection control of the aqueous urea solution into the exhaust pipe 11, the flow path switching valve 35 is held in the first state so that the aqueous urea solution flows from the storage tank 50 side to the reducing agent injection valve 31 side. . Further, when the urea aqueous solution in the reducing agent supply device 30 is recovered in the storage tank 50, the flow path switching valve 35 is arranged so that the urea aqueous solution flows from the reducing agent injection valve 31 side to the storage tank 50 side. Held in a state.

例えば、流路切換弁３５が、非通電状態において第１の状態となり、通電状態において第２の状態となる場合、尿素水溶液の噴射制御時には流路切換弁３５は非通電状態で維持され、尿素水溶液の回収時に制御装置１００は流路切換弁３５を通電状態とする。なお、流路切換弁３５を用いる代わりに、逆回転可能なポンプを用いたり、回収用の第２のポンプを用いたりすることによって、尿素水溶液が回収可能になっていてもよい。   For example, when the flow path switching valve 35 is in the first state in the non-energized state and in the second state in the energized state, the flow path switching valve 35 is maintained in the non-energized state during the urea aqueous solution injection control. At the time of collecting the aqueous solution, the control device 100 turns on the flow path switching valve 35. Instead of using the flow path switching valve 35, the urea aqueous solution may be recoverable by using a reversely rotatable pump or a second recovery pump.

還元剤噴射弁３１としては、例えば、通電制御により開弁又は閉弁が切り換えられる電磁式開閉弁が用いられる。かかる還元剤噴射弁３１は、電磁コイルを備え、当該電磁コイルへの通電により発生する磁力によって弁体が移動して開弁する構造を有している。制御装置１００は、例えば、第２の還元剤供給通路５７内の圧力が所定の目標値となるようにポンプ４１の出力を制御しつつ、尿素水溶液の目標噴射量に応じて還元剤噴射弁３１の開弁時間をデューティ制御する。   As the reducing agent injection valve 31, for example, an electromagnetic on-off valve whose opening or closing is switched by energization control is used. The reducing agent injection valve 31 includes an electromagnetic coil, and has a structure in which the valve body is moved and opened by the magnetic force generated by energizing the electromagnetic coil. The control device 100 controls the output of the pump 41 so that the pressure in the second reducing agent supply passage 57 reaches a predetermined target value, and the reducing agent injection valve 31 according to the target injection amount of the aqueous urea solution, for example. The duty of the valve opening time of is controlled.

なお、還元剤噴射弁３１は、図１に示したように、排気が流れる排気管１１の本流部分に取り付けられてもよいし、排気管１１の本流部分から分岐した分岐部分に取り付けられてもよい。この場合、尿素水溶液は、分岐管を通じて排気管１１の本流部分に供給される。   As shown in FIG. 1, the reducing agent injection valve 31 may be attached to a main portion of the exhaust pipe 11 through which exhaust gas flows, or may be attached to a branch portion of the exhaust pipe 11 branched from the main portion. Good. In this case, the urea aqueous solution is supplied to the mainstream portion of the exhaust pipe 11 through the branch pipe.

制御装置１００は、ポンプ４１、流路切換弁３５及び還元剤噴射弁３１をそれぞれ駆動する複数の駆動回路を備える。それぞれの駆動回路は、マイクロコンピュータ等から送信される信号に基づいて動作して、ポンプ４１、流路切換弁３５及び還元剤噴射弁３１を駆動する。   The control device 100 includes a plurality of drive circuits that drive the pump 41, the flow path switching valve 35, and the reducing agent injection valve 31, respectively. Each drive circuit operates based on a signal transmitted from a microcomputer or the like to drive the pump 41, the flow path switching valve 35 and the reducing agent injection valve 31.

制御装置１００の一部又は全部は、例えば、マイクロコンピュータ又はマイクロプロセッサユニット等で構成されていてもよい。また、制御装置１００の一部又は全部は、ファームウェア等の更新可能なもので構成されていてもよく、また、ＣＰＵ等からの指令によって実行されるプログラムモジュール等であってもよい。   Part or all of the control device 100 may be configured by, for example, a microcomputer or a microprocessor unit. In addition, a part or all of the control device 100 may be configured by an updater such as firmware, or may be a program module or the like executed by a command from the CPU or the like.

＜３．オリフィス部＞
次に、リターン通路５９に備えられたオリフィス部７０について詳細に説明する。 <3. Orifice part>
Next, the orifice portion 70 provided in the return passage 59 will be described in detail.

図２は、本実施形態に係る還元剤供給装置３０に備えられたオリフィス部７０の構成例を示す模式図である。図２において、右側（矢印Ａの方向）が第２の還元剤供給通路５７側であり、左側（矢印Ｂの方向）が貯蔵タンク５０側である。図２は、ポンプ４１により尿素水溶液を還元剤噴射弁３１側に圧送している期間のオリフィス部７０の状態を示している。   FIG. 2 is a schematic diagram showing a configuration example of the orifice portion 70 provided in the reducing agent supply device 30 according to the present embodiment. In FIG. 2, the right side (the direction of arrow A) is the second reducing agent supply passage 57 side, and the left side (the direction of arrow B) is the storage tank 50 side. FIG. 2 shows a state of the orifice portion 70 during a period in which the pump 41 pumps the urea aqueous solution to the reducing agent injection valve 31 side.

オリフィス部７０は、第１の通路部材７１、第２の通路部材７５、変位部材７８及び付勢部材７３を備える。このうち、変位部材７８及び付勢部材７３は、流路面積可変機構８０を構成する。第１の通路部材７１は、軸方向の両端（図の左右）に開口する内部通路７１ａを有する。第２の通路部材７５は、軸方向の一端側（図の左側）に開口する内部通路７５ａと、軸方向の他端側（図の右側）に開口する変位部材摺動孔７５ｂと、一端が変位部材摺動孔７５ｂの周面に開口し他端が内部通路７５ａに開口する絞り通路７５ｃと、内部通路７５ａと変位部材摺動孔７５ｂとを軸方向に接続する連通孔７５ｄとを有する。   The orifice portion 70 includes a first passage member 71, a second passage member 75, a displacement member 78, and a biasing member 73. Of these, the displacement member 78 and the urging member 73 constitute a flow path area varying mechanism 80. The first passage member 71 has internal passages 71a that are open at both ends (left and right in the drawing) in the axial direction. The second passage member 75 has an internal passage 75a that opens to one axial side (left side in the drawing), a displacement member sliding hole 75b that opens to the other axial side (right side in the drawing), and one end The displacement member sliding hole 75b has a throttle passage 75c which is open to the peripheral surface and the other end of which is opened to the internal passage 75a, and a communication hole 75d which axially connects the internal passage 75a and the displacement member sliding hole 75b.

第１の通路部材７１の内部通路７１ａの一端側は第２の還元剤供給通路５７側のリターン通路５９に連通し、他端側は第２の通路部材７５の変位部材摺動孔７５ｂに連通している。第２の通路部材７５の変位部材摺動孔７５ｂの一端側は第１の通路部材７１の内部通路７１ａに連通し、他端側は連通孔７５ｄに連通している。第２の通路部材７５の内部通路７５ａの一端側は貯蔵タンク５０側のリターン通路５９に連通し、他端側は連通孔７５ｄに連通している。   One end side of the internal passage 71a of the first passage member 71 communicates with the return passage 59 on the second reducing agent supply passage 57 side, and the other end side communicates with the displacement member sliding hole 75b of the second passage member 75. is doing. One end side of the displacement member sliding hole 75b of the second passage member 75 communicates with the internal passage 71a of the first passage member 71, and the other end side communicates with the communication hole 75d. One end side of the internal passage 75a of the second passage member 75 communicates with the return passage 59 on the storage tank 50 side, and the other end side thereof communicates with the communication hole 75d.

第２の通路部材７５の変位部材摺動孔７５ｂには、変位部材７８が進退移動可能に保持されている。変位部材摺動孔７５ｂの直径は、第１の通路部材７１の内部通路７１ａの直径よりも大きくなっている。変位部材７８と第１の通路部材７１との間には付勢部材７３としてのコイルスプリングが備えられ、変位部材７８は、付勢部材７３によって内部通路７５ａ側に付勢されている。なお、付勢部材７３は、コイルスプリングに限られない。   The displacement member 78 is held in the displacement member sliding hole 75b of the second passage member 75 so as to be movable back and forth. The diameter of the displacement member sliding hole 75b is larger than the diameter of the internal passage 71a of the first passage member 71. A coil spring as a biasing member 73 is provided between the displacement member 78 and the first passage member 71, and the displacement member 78 is biased toward the internal passage 75a by the biasing member 73. The biasing member 73 is not limited to the coil spring.

連通孔７５ｄの直径は、変位部材摺動孔７５ｂの直径よりも小さくなっており、付勢部材７３により付勢される変位部材７８は、連通孔７５ｄの周囲の当接部７７に当接して位置決めされている。変位部材７８は、内部通路７８ａを有する。内部通路７８ａの一端は、第１の通路部材７１側に位置する変位部材７８の軸方向の一端側に開口し、他端は変位部材７８の外周面に開口する。変位部材７８が当接部７７に当接した状態において、変位部材７８の内部通路７８ａと絞り通路７５ｃとが連通する。   The diameter of the communication hole 75d is smaller than the diameter of the displacement member sliding hole 75b, and the displacement member 78 urged by the urging member 73 contacts the contact portion 77 around the communication hole 75d. It is positioned. The displacement member 78 has an internal passage 78a. One end of the internal passage 78 a opens to one end side of the displacement member 78 located on the first passage member 71 side in the axial direction, and the other end opens to the outer peripheral surface of the displacement member 78. When the displacement member 78 is in contact with the contact portion 77, the internal passage 78a of the displacement member 78 and the throttle passage 75c communicate with each other.

図２に示す状態では、第２の還元剤供給通路５７に圧送される尿素水溶液の一部がリターン通路５９を介して貯蔵タンク５０に戻される際に、変位部材７８の内部通路７８ａ及び絞り通路７５ｃを通過する。これらの内部通路７８ａ及び絞り通路７５ｃは、流路面積が小さくされていることから、尿素水溶液の流通に抵抗が与えられ、第２の還元剤供給通路５７内の圧力が保持されやすくなる。このとき、変位部材７８の第１の通路部材７１側の端面には、付勢部材７３の付勢力と第２の還元剤供給通路５７内の圧力に起因する正圧とが作用し、変位部材７８の貯蔵タンク５０側の端面には大気圧が作用するため、変位部材７８は、当接部７７に当接した状態で維持される。   In the state shown in FIG. 2, when a part of the urea aqueous solution that is pressure-fed to the second reducing agent supply passage 57 is returned to the storage tank 50 through the return passage 59, the internal passage 78a of the displacement member 78 and the throttle passage. Pass 75c. Since the flow passage areas of the internal passage 78a and the throttle passage 75c are made small, resistance is imparted to the flow of the urea aqueous solution, and the pressure in the second reducing agent supply passage 57 is easily maintained. At this time, the urging force of the urging member 73 and the positive pressure resulting from the pressure in the second reducing agent supply passage 57 act on the end surface of the displacing member 78 on the first passage member 71 side, and the displacing member Since the atmospheric pressure acts on the end surface of the storage tank 50 side of 78, the displacement member 78 is maintained in the state of being in contact with the contact portion 77.

図３は、尿素水溶液の回収制御中のオリフィス部７０の状態を示している。ポンプ４１により尿素水溶液を貯蔵タンク５０内に吸い戻している間、第２の還元剤供給通路５７内には負圧が発生する。この負圧により、変位部材７８は、付勢部材７３の付勢力に抗して第１の通路部材７１側に移動する。これにより、変位部材７８の外周面に開口する内部通路７８ａと、当該内部通路７８ａに対向する絞り通路７５ｃとの境界により形成される流路面積は、変位部材７８が当接部７７に当接した状態での流路面積よりも小さくなる。つまり、尿素水溶液の回収制御中、オリフィス部７０を通過して貯蔵タンク５０側から第２の還元剤供給通路５７側へと流れる尿素水溶液に付与される抵抗が高められ、リターン通路５９内の尿素水溶液は第２の還元剤供給通路５７内の尿素水溶液よりも吸い戻されにくくなっている。   FIG. 3 shows a state of the orifice portion 70 during the recovery control of the urea aqueous solution. While the urea aqueous solution is sucked back into the storage tank 50 by the pump 41, a negative pressure is generated in the second reducing agent supply passage 57. Due to this negative pressure, the displacement member 78 moves toward the first passage member 71 side against the biasing force of the biasing member 73. As a result, the flow passage area formed by the boundary between the internal passage 78a opening to the outer peripheral surface of the displacement member 78 and the throttle passage 75c facing the internal passage 78a is such that the displacement member 78 contacts the contact portion 77. It becomes smaller than the area of the flow path in the opened state. That is, during the recovery control of the urea aqueous solution, the resistance imparted to the urea aqueous solution flowing from the storage tank 50 side to the second reducing agent supply passage 57 side through the orifice 70 is increased, and the urea in the return passage 59 is increased. The aqueous solution is less likely to be sucked back than the aqueous urea solution in the second reducing agent supply passage 57.

ただし、尿素水溶液の回収制御中、オリフィス部７０内の流路が完全に閉じられると、リターン通路５９内の尿素水容液を回収することが困難になることから、変位部材７８が変位した状態においてもオリフィス部７０内の流路が完全に閉じられることがないように設計される。   However, when the flow path in the orifice portion 70 is completely closed during the recovery control of the urea aqueous solution, it becomes difficult to recover the urea aqueous solution in the return passage 59. Therefore, the displacement member 78 is displaced. Also in the above, it is designed so that the flow path in the orifice portion 70 is not completely closed.

尿素水溶液を回収する際、第２の還元剤供給通路５７内の尿素水溶液の吸い戻し量は、主として第２の還元剤供給通路５７側の容量、還元剤噴射弁３１の噴射孔の面積の和、リターン通路５９側の容量、リターン通路５９の最小流路面積、及びポンプ４１の駆動により生じる負圧により決定される。リターン通路５９内の尿素水溶液が、第２の還元剤供給通路５７内の尿素水溶液よりも早く回収されてしまうと、以降、リターン通路５９には貯蔵タンク５０側から空気が吸引されることになって、第２の還元剤供給通路５７内の尿素水溶液が回収されにくくなる。   When recovering the urea aqueous solution, the amount of sucking back the urea aqueous solution in the second reducing agent supply passage 57 is mainly the sum of the capacity of the second reducing agent supply passage 57 side and the area of the injection hole of the reducing agent injection valve 31. , The capacity of the return passage 59 side, the minimum flow passage area of the return passage 59, and the negative pressure generated by driving the pump 41. When the urea aqueous solution in the return passage 59 is collected earlier than the urea aqueous solution in the second reducing agent supply passage 57, air is sucked into the return passage 59 from the storage tank 50 side. As a result, the urea aqueous solution in the second reducing agent supply passage 57 becomes difficult to collect.

図４は、還元剤供給装置３０の流路構成を模式的に示す図である。一般的に、第２の還元剤供給通路５７とリターン通路５９との分岐点５６から還元剤噴射弁３１の先端までの容量Ｖａは、当該分岐点５６からリターン通路５９の端部までの容量Ｖｂよりも大きい。このため、第２の還元剤供給通路５７側の最小流路面積と、リターン通路５９側の最小流路面積とが同等である場合、リターン通路５９内の尿素水溶液が第２の還元剤供給通路５７内の尿素水溶液よりも早く吸い戻される。これを防ぐためには、リターン通路５９側の最小流路面積を第２の還元剤供給通路５７側の最小流路面積よりも小さくする必要がある。   FIG. 4 is a diagram schematically showing the flow channel configuration of the reducing agent supply device 30. Generally, the capacity Va from the branch point 56 between the second reducing agent supply passage 57 and the return passage 59 to the tip of the reducing agent injection valve 31 is the capacity Vb from the branch point 56 to the end portion of the return passage 59. Greater than. Therefore, when the minimum flow passage area on the second reducing agent supply passage 57 side is equal to the minimum flow passage area on the return passage 59 side, the urea aqueous solution in the return passage 59 is not contained in the second reducing agent supply passage. It is sucked back faster than the aqueous urea solution in 57. In order to prevent this, it is necessary to make the minimum flow passage area on the return passage 59 side smaller than the minimum flow passage area on the second reducing agent supply passage 57 side.

第２の還元剤供給通路５７側の最小流路面積は、還元剤噴射弁３１の噴射孔の面積の和であるため、オリフィス部７０の変位部材７８が変位して流路面積が小さくなるときの流路面積が、少なくとも、還元剤噴射弁３１の噴射孔の面積の和よりも小さくなるように設計される。具体的には、ポンプ４１の駆動により生じる負圧と付勢部材７３の付勢力とにより、変位部材７８の変位量及び変位状態での流路面積が定まることから、少なくともリターン通路５９側の尿素水溶液が第２の還元剤供給通路５７側の尿素水溶液よりも先に吸い戻されないように、付勢部材７３の付勢力や内部通路７８ａあるいは絞り通路７５ｃの断面積が設計される。これにより、第２の還元剤供給通路５７内の尿素水溶液の残留量を低減することができる。   Since the minimum flow passage area on the second reducing agent supply passage 57 side is the sum of the areas of the injection holes of the reducing agent injection valve 31, when the displacement member 78 of the orifice portion 70 is displaced and the flow passage area becomes small. Is designed to be at least smaller than the sum of the areas of the injection holes of the reducing agent injection valve 31. Specifically, since the displacement amount of the displacement member 78 and the flow passage area in the displaced state are determined by the negative pressure generated by the driving of the pump 41 and the biasing force of the biasing member 73, the urea on at least the return passage 59 side is determined. The biasing force of the biasing member 73 and the cross-sectional area of the internal passage 78a or the throttle passage 75c are designed so that the aqueous solution is not sucked back before the urea aqueous solution on the second reducing agent supply passage 57 side. As a result, the residual amount of the urea aqueous solution in the second reducing agent supply passage 57 can be reduced.

望ましくは、第２の還元剤供給通路５７側の尿素水溶液と、リターン通路５９側の尿素水溶液とが、同時期に回収されるように設計されるとよい。これにより、第２の還元剤供給通路５７及びリターン通路５９内の尿素水溶液の残留量を低減することができる。   Desirably, the urea aqueous solution on the second reducing agent supply passage 57 side and the urea aqueous solution on the return passage 59 side may be designed to be recovered at the same time. As a result, the residual amount of the urea aqueous solution in the second reducing agent supply passage 57 and the return passage 59 can be reduced.

尿素水溶液の回収制御中の変位部材７８の位置、つまり、内部通路７８ａと絞り通路７５ｃとの境界により形成される流路面積は、調節部材を用いて調節することもできる。図５は、尿素水溶液の回収制御中のリターン通路５９内の最小流路面積を調節する調節部材７９を備えた例を示す。調節部材７９は、開口部７９ａを有し、当該開口部７９ａが第１の通路部材７１の内部通路７１ａに連通するようにして、第１の通路部材７１の端面に配置される。かかる調節部材７９の厚さ（軸方向の幅）を調節することにより、付勢部材７３の付勢力が同じであっても変位部材７８の位置を調節することができる。   The position of the displacement member 78 during the recovery control of the urea aqueous solution, that is, the flow passage area formed by the boundary between the internal passage 78a and the throttle passage 75c can be adjusted by using an adjusting member. FIG. 5 shows an example provided with an adjusting member 79 for adjusting the minimum flow passage area in the return passage 59 during the recovery control of the urea aqueous solution. The adjusting member 79 has an opening 79a and is arranged on the end surface of the first passage member 71 so that the opening 79a communicates with the internal passage 71a of the first passage member 71. By adjusting the thickness (width in the axial direction) of the adjusting member 79, the position of the displacement member 78 can be adjusted even if the biasing force of the biasing member 73 is the same.

なお、調節部材７９は、第１の通路部材７１の内部通路７１ａ内に取り付けられてもよく、変位部材摺動孔７５ｂ内に取り付けられてもよい。   The adjusting member 79 may be attached inside the internal passage 71a of the first passage member 71 or inside the displacement member sliding hole 75b.

図６及び図７は、オリフィス部９０の変形例を示す。変形例にかかるオリフィス部９０は、付勢部材を用いずに、変位部材９８の自重と第２の還元剤供給通路５７内に生じる負圧とにより変位部材９８が変位して流路面積が変化する流路面積可変機構８０を備える。図６及び図７において、上側（矢印Ａの方向）が第２の還元剤供給通路５７側であり、下側（矢印Ｂの方向）が貯蔵タンク５０側である。   6 and 7 show modified examples of the orifice portion 90. In the orifice portion 90 according to the modified example, the displacement member 98 is displaced by the own weight of the displacement member 98 and the negative pressure generated in the second reducing agent supply passage 57 without changing the flow passage area, without using a biasing member. The flow path area variable mechanism 80 is provided. 6 and 7, the upper side (direction of arrow A) is the second reducing agent supply passage 57 side, and the lower side (direction of arrow B) is the storage tank 50 side.

変形例に係るオリフィス部７０において、変位部材９８の上面には環状突出部９９が形成されるとともに、その一部に、一つ又は複数の溝部９５が形成されている。ポンプ４１により尿素水溶液が第２の還元剤供給通路５７内に供給されている間、変位部材９８は自重により落下して、支持部９２上に位置する（図６）。一方、ポンプ４１により尿素水溶液が吸い戻され、第２の還元剤供給通路５７内に負圧が発生すると、当該負圧により変位部材９８が浮上する（図７）。この状態では、オリフィス部９０の最小流路面積が溝部９５の流路面積の和となって、図６の状態に比べて小さくなる。これにより、リターン通路５９内の尿素水溶液が吸い戻されにくくなって、第２の還元剤供給通路５７内の尿素水溶液の残留量を低減することができる。   In the orifice portion 70 according to the modified example, an annular protruding portion 99 is formed on the upper surface of the displacement member 98, and one or a plurality of groove portions 95 are formed in a part thereof. While the urea aqueous solution is being supplied to the second reducing agent supply passage 57 by the pump 41, the displacement member 98 falls due to its own weight and is positioned on the support portion 92 (FIG. 6). On the other hand, when the urea aqueous solution is sucked back by the pump 41 and a negative pressure is generated in the second reducing agent supply passage 57, the displacement member 98 floats due to the negative pressure (FIG. 7). In this state, the minimum flow passage area of the orifice portion 90 becomes the sum of the flow passage areas of the groove portions 95, which is smaller than that in the state of FIG. As a result, the urea aqueous solution in the return passage 59 is less likely to be sucked back, and the residual amount of the urea aqueous solution in the second reducing agent supply passage 57 can be reduced.

変形例にかかるオリフィス部７０の場合、環状突出部９９の高さ、あるいは、溝部９５の深さ又は幅を調節することにより、尿素水溶液の回収制御中のリターン通路５９の最小流路面積を調節することができる。この場合、環状突出部９９あるいは溝部９５が調節部として機能する。   In the case of the orifice portion 70 according to the modified example, the minimum flow passage area of the return passage 59 during the urea aqueous solution recovery control is adjusted by adjusting the height of the annular protruding portion 99 or the depth or width of the groove portion 95. can do. In this case, the annular protrusion 99 or the groove 95 functions as an adjusting portion.

以上説明したとおり、本実施形態に係る還元剤供給装置３０は、尿素水溶液の回収制御時のリターン通路５９側の最小流路面積を、尿素水溶液の噴射制御時のリターン通路５９側の最小流路面積よりも小さくする流路面積可変機構８０を備える。このため、第２の還元剤供給通路５７内の尿素水溶液よりも先にリターン通路５９内の尿素水溶液が吸い戻されることを防ぎ、少なくとも第２の還元剤供給通路５７内に尿素水溶液が残留することを抑制することができる。   As described above, in the reducing agent supply device 30 according to the present embodiment, the minimum flow passage area on the return passage 59 side during the urea aqueous solution recovery control is set to be the minimum flow passage area on the return passage 59 side during the urea aqueous solution injection control. The flow path area variable mechanism 80 for reducing the area is provided. Therefore, the urea aqueous solution in the return passage 59 is prevented from being sucked back before the urea aqueous solution in the second reducing agent supply passage 57, and the urea aqueous solution remains at least in the second reducing agent supply passage 57. Can be suppressed.

以上、添付図面を参照しながら本発明の好適な実施形態について詳細に説明したが、本発明はかかる例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、特許請求の範囲に記載された技術的思想の範疇内において、各種の変更例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。   The preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

５：内燃機関、３０：還元剤供給装置、３１：還元剤噴射弁、４１：ポンプ、５０：貯蔵タンク、５７：第２の還元剤供給通路、５９：リターン通路、７０：オリフィス部、７３：付勢部材、７８：変位部材、７８ａ：内部通路、７９：調節部材、８０：流路面積可変機構
5: internal combustion engine, 30: reducing agent supply device, 31: reducing agent injection valve, 41: pump, 50: storage tank, 57: second reducing agent supply passage, 59: return passage, 70: orifice portion, 73: Energizing member, 78: Displacement member, 78a: Internal passage, 79: Adjusting member, 80: Flow path area varying mechanism

Claims (4)

タンク（５０）内の液体還元剤を吸い上げて圧送するポンプ（４１）と、前記ポンプ（４１）により圧送される前記液体還元剤を内燃機関（５）の排気通路に噴射する還元剤噴射弁（３１）と、前記ポンプ（４１）と前記還元剤噴射弁（３１）とを接続する還元剤供給通路（５７）と、前記ポンプ（４１）により圧送される前記液体還元剤の一部を前記タンク（５０）に戻すために前記還元剤供給通路（５７）から分岐して設けられたリターン通路（５９）と、を備え、
前記内燃機関（５）の運転時には前記液体還元剤を前記還元剤噴射弁（３１）側に供給する制御が実行され、前記内燃機関（５）の停止時には前記液体還元剤を吸い戻して前記タンク（５０）に回収する制御が実行される還元剤供給装置（３０）において、
前記リターン通路（５９）の途中に、前記還元剤供給通路（５７）内に生じる圧力によって流路面積が変化する流路面積可変機構（８０）を備え、
前記流路面積可変機構（８０）は、
前記液体還元剤を回収する制御の実行時に、前記液体還元剤を供給する制御の実行時に比べて前記流路面積を小さくして、前記液体還元剤を通過させる、
ことを特徴とする、還元剤供給装置。 A pump (41) for sucking up and pumping the liquid reducing agent in the tank (50), and a reducing agent injection valve (for injecting the liquid reducing agent pumped by the pump (41) into the exhaust passage of the internal combustion engine (5) ( 31), a reducing agent supply passage (57) connecting the pump (41) and the reducing agent injection valve (31), and a part of the liquid reducing agent pumped by the pump (41) to the tank. A return passage (59) branched from the reducing agent supply passage (57) for returning to (50),
When the internal combustion engine (5) is in operation, control is performed to supply the liquid reducing agent to the reducing agent injection valve (31) side, and when the internal combustion engine (5) is stopped, the liquid reducing agent is sucked back to the tank. In the reducing agent supply device (30) in which the control to recover to (50) is executed,
In the middle of the return passage (59), a flow passage area variable mechanism (80) for changing the flow passage area by the pressure generated in the reducing agent supply passage (57) is provided.
The channel area variable mechanism (80) is
When the control for recovering the liquid reducing agent is executed, the flow passage area is made smaller than when the control for supplying the liquid reducing agent is executed, and the liquid reducing agent is passed through.
A reducing agent supply device characterized by the above. 前記流路面積可変機構（８０）は、
前記リターン通路（５９）内を、前記還元剤供給通路（５７）側及び前記タンク（５０）側に移動可能な変位部材（７８）を含み、
前記変位部材（７８）は、
前記液体還元剤を供給する制御の実行時に前記タンク（５０）側に位置するとともに、
前記液体還元剤を回収する制御の実行時に前記還元剤供給通路（５７）内に生じる負圧により前記還元剤供給通路（５７）側に移動して、前記流路面積を小さくする、
ことを特徴とする、請求項１に記載の還元剤供給装置。 The channel area variable mechanism (80) is
A displacement member (78) movable in the return passage (59) toward the reducing agent supply passage (57) and the tank (50);
The displacement member (78) is
It is located on the side of the tank (50) when the control for supplying the liquid reducing agent is executed, and
When the control for collecting the liquid reducing agent is executed, the negative pressure generated in the reducing agent supply passage (57) moves to the reducing agent supply passage (57) side to reduce the flow passage area,
The reducing agent supply apparatus according to claim 1, wherein: 前記流路面積可変機構（８０）は、
前記変位部材（７８）が前記還元剤供給通路（５７）側に移動した際の前記変位部材（７８）の位置を設定する調節部（７９）を含む、
ことを特徴とする、請求項２に記載の還元剤供給装置。 The channel area variable mechanism (80) is
An adjusting portion (79) for setting the position of the displacement member (78) when the displacement member (78) moves to the reducing agent supply passageway (57) side;
The reducing agent supply apparatus according to claim 2, wherein: 前記変位部材（７８）が前記還元剤供給通路（５７）側に移動した際の前記流路面積が、前記還元剤供給通路（５７）及び前記還元剤噴射弁（３１）における前記液体還元剤が流通可能な空間の容量に基づいて設定される、
ことを特徴とする、請求項２又は３に記載の還元剤供給装置。
The flow path area when the displacement member (78) moves to the reducing agent supply passage (57) side is equal to the liquid reducing agent in the reducing agent supply passage (57) and the reducing agent injection valve (31). Set based on the volume of the space that can be distributed,
The reducing agent supply device according to claim 2 or 3, characterized in that.
JP2018201437A 2018-10-26 2018-10-26 Reducing agent supply device Active JP7203562B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2018201437A JP7203562B2 (en) 2018-10-26 2018-10-26 Reducing agent supply device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2018201437A JP7203562B2 (en) 2018-10-26 2018-10-26 Reducing agent supply device

Publications (2)

Publication Number Publication Date
JP2020067055A true JP2020067055A (en) 2020-04-30
JP7203562B2 JP7203562B2 (en) 2023-01-13

Family

ID=70389924

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2018201437A Active JP7203562B2 (en) 2018-10-26 2018-10-26 Reducing agent supply device

Country Status (1)

Country Link
JP (1) JP7203562B2 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013148028A (en) * 2012-01-20 2013-08-01 Bosch Corp Reducing agent supply device
JP2014095337A (en) * 2012-11-09 2014-05-22 Bosch Corp Reductant supply device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013148028A (en) * 2012-01-20 2013-08-01 Bosch Corp Reducing agent supply device
JP2014095337A (en) * 2012-11-09 2014-05-22 Bosch Corp Reductant supply device

Also Published As

Publication number Publication date
JP7203562B2 (en) 2023-01-13

Similar Documents

Publication Publication Date Title
JP4911193B2 (en) Exhaust gas purification system for internal combustion engine
JP5547815B2 (en) Reducing agent injection valve abnormality determination device and reducing agent supply device
JP4894827B2 (en) Reducing agent supply system
JP2008101564A (en) Exhaust emission control device for engine
JP2012127214A (en) Reducing agent supplying system, and exhaust gas purifying system of internal combustion engine
RU2635731C1 (en) Reducing agent supply system
JP6017866B2 (en) Reducing agent supply device, liquid reducing agent recovery control method, and exhaust purification device
JP2016205363A (en) Urea water supply system
JPWO2013051315A1 (en) Reducing agent supply device
JP5914004B2 (en) Reducing agent supply device
JP6172468B2 (en) Exhaust gas purification device for internal combustion engine
JP7203562B2 (en) Reducing agent supply device
JP2012163029A (en) Reducing agent supply device
JP6905910B2 (en) Diagnostic device and diagnostic method
JP2012127308A (en) Reducing agent supply device, and exhaust emission control device for internal combustion engine
JP6576813B2 (en) Reducing agent supply device
WO2015001858A1 (en) Reducing agent supply device and method of controlling same
JP5948226B2 (en) Reducing agent supply device
JPWO2018047554A1 (en) Control device
CN104870766A (en) Method for controlling reductant supply device, and reductant supply device
JP2014095337A (en) Reductant supply device
US10753256B2 (en) Injection controller
JP2020101112A (en) Reductant supplying device and cooling holder
JP2021092207A (en) Reductant injection valve
JP2021063489A (en) Reducing agent supply control device

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20210720

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20220721

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20220721

A601 Written request for extension of time

Free format text: JAPANESE INTERMEDIATE CODE: A601

Effective date: 20221014

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20221208

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20221223

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20221227

R150 Certificate of patent or registration of utility model

Ref document number: 7203562

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150