JP2009150343A - Urea water pump and urea water injection system - Google Patents

Urea water pump and urea water injection system Download PDF

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JP2009150343A
JP2009150343A JP2007330222A JP2007330222A JP2009150343A JP 2009150343 A JP2009150343 A JP 2009150343A JP 2007330222 A JP2007330222 A JP 2007330222A JP 2007330222 A JP2007330222 A JP 2007330222A JP 2009150343 A JP2009150343 A JP 2009150343A
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urea water
pump
suction
liquid level
urea
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JP4853472B2 (en
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Hitoshi Sekijima
仁 関島
Masatoshi Kuroyanagi
正利 黒柳
Yoshiaki Nishijima
義明 西島
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Denso Corp
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Denso Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1433—Pumps
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urea water pump for ensuring reliable operation of a pump part and supplies of urea water by reducing the precipitation of urea crystals even when the urea water left reduced, and also to provide a urea water injection system using the same. <P>SOLUTION: A suction pipe part 50 has an upper curved portion 54 as an uppermost portion located above a pump discharge portion 27 of the pump part 21. Thus, even when the liquid level of the urea water in a urea water tank 11 is lowered, the liquid level position of the urea water in the pump part 21 at the side of a pump suction portion 26 beyond the upper curved portion 54 of the suction pipe part 50 is located at the same level as a lower end 56 of the upper curved portion 54. The pump part 21 is then immersed in the urea water independently of the liquid level position of the urea water in the urea water tank 11. As a result, an impeller 24 and a casing 23 of the pump part 21 are immersed in the urea water to reduce the precipitation of urea crystals on the impeller 24 and the casing 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、尿素水ポンプおよび尿素水噴射システムに関し、特に内燃機関の排気に添加される尿素水を供給する尿素水ポンプおよび尿素水噴射システムに関する。   The present invention relates to a urea water pump and a urea water injection system, and more particularly to a urea water pump and a urea water injection system that supply urea water added to exhaust gas of an internal combustion engine.

内燃機関、特にディーゼルエンジンから排出されるＮＯｘを還元する排気浄化装置として、ＳＣＲ（Selective Catalytic Reduction）システムが公知である。ＳＣＲシステムを用いた排気浄化装置は、例えば尿素などを還元剤として噴射することにより、排気に含まれるＮＯｘから窒素と水とを生成する。尿素水は、タンクに貯えられ、液面センサによってタンクにおける残量が検出されている（特許文献１参照）。ところで、尿素水は、空気に触れると水分が蒸発し、溶解している尿素が結晶として析出することがある。そのため、尿素を供給する配管の目詰まりを招き、尿素水の供給が不十分になるおそれがある。そこで、加圧手段を設け、配管に残存する尿素水を除去することが提案されている（特許文献２参照）。
特開２００６− ９０３３４号公報 特開２００６−１３２３８４号公報 An SCR (Selective Catalytic Reduction) system is known as an exhaust purification device that reduces NOx discharged from an internal combustion engine, particularly a diesel engine. An exhaust gas purification apparatus using an SCR system generates nitrogen and water from NOx contained in exhaust gas, for example, by injecting urea or the like as a reducing agent. The urea water is stored in the tank, and the remaining amount in the tank is detected by a liquid level sensor (see Patent Document 1). By the way, when urea water is exposed to air, water may be evaporated and dissolved urea may be precipitated as crystals. Therefore, the piping for supplying urea may be clogged, and the supply of urea water may be insufficient. Therefore, it has been proposed to provide a pressurizing means to remove the urea water remaining in the pipe (see Patent Document 2).
JP 2006-90334 A JP 2006-132384 A

しかしながら、尿素水は配管に限らず尿素水ポンプにおいても水分が蒸発する場合がある。尿素水ポンプは、タンクに貯えられている尿素水を排気通路側へ供給する。タンクに貯えられている尿素水の液面は、例えば内燃機関の長期の運転停止にともない尿素水が消費されないときでも、水分の蒸発によって低下する。そのため、尿素水ポンプの内部における尿素水も減少する。尿素水ポンプのポンプ部は、例えば回転部材と回転部材を収容するケーシングとを有している。この回転部材は、ケーシングとの間にわずかなクリアランスを形成して回転している。そのため、回転部材とケーシングとの間に尿素の結晶が析出すると、析出した結晶が回転部材またはケーシングを損傷あるいは摩耗させたり、回転部材とケーシングとを固着させるおそれがある。その結果、尿素水が減少したまま尿素水ポンプを放置すると、析出した結晶によるポンプ部の作動不良を招き、尿素水の供給が困難になるおそれがある。   However, the urea water may be evaporated not only in the piping but also in the urea water pump. The urea water pump supplies urea water stored in the tank to the exhaust passage side. The liquid level of the urea water stored in the tank is lowered by the evaporation of water even when the urea water is not consumed, for example, due to a long-term shutdown of the internal combustion engine. Therefore, urea water in the urea water pump is also reduced. The pump part of the urea water pump has, for example, a rotating member and a casing that houses the rotating member. The rotating member rotates with a slight clearance between the rotating member and the casing. For this reason, when urea crystals are precipitated between the rotating member and the casing, the precipitated crystals may damage or wear the rotating member or the casing, or may cause the rotating member and the casing to adhere to each other. As a result, if the urea water pump is left with the urea water decreased, the pump part may malfunction due to the precipitated crystals, which may make it difficult to supply the urea water.

そこで、本発明は、上記の課題に鑑みてなされたものであり、その目的は、尿素水が減少したまま放置されても、尿素の結晶の析出が低減され、ポンプ部の確実な作動および尿素水の供給が確保される尿素水ポンプおよびこれを用いた尿素水噴射システムを提供することにある。   Therefore, the present invention has been made in view of the above problems, and its purpose is to reduce the precipitation of urea crystals even when the urea water is left in a reduced state, and to ensure the operation of the pump unit and the urea. It is an object of the present invention to provide a urea water pump in which water supply is ensured and a urea water injection system using the urea water pump.

請求項１記載の発明では、接続通路を形成する吸入管部は少なくとも一部がポンプ部よりも上方に位置している。そのため、接続通路に残存する尿素水の液面位置は、ポンプ部よりも上方に位置する。これにより、ポンプ部に残存している尿素水は、接続通路を経由して外部に排出されない。その結果、ポンプ部には、接続通路とともに尿素水が残存する。ポンプ部に尿素水が残存することにより、ポンプ部は常に尿素水に浸され、空気との接触が回避される。したがって、液面位置が低下したまま放置されても、尿素の結晶の析出が低減され、ポンプ部の確実な作動および尿素水の供給を確保することができる。   According to the first aspect of the present invention, at least a part of the suction pipe part forming the connection passage is located above the pump part. Therefore, the liquid level position of the urea water remaining in the connection passage is located above the pump unit. Thereby, the urea water remaining in the pump part is not discharged to the outside via the connection passage. As a result, urea water remains in the pump part together with the connection passage. Since urea water remains in the pump section, the pump section is always immersed in the urea water and contact with air is avoided. Therefore, even if the liquid level position is left lowered, precipitation of urea crystals is reduced, and a reliable operation of the pump unit and supply of urea water can be ensured.

請求項２記載の発明では、吸入管部はポンプ部から尿素水が吐出される吐出部よりも上方に位置している。これにより、接続通路に残存する尿素水の液面位置は、ポンプ部だけでなくモータ部よりも上方に位置する。そのため、ポンプ部だけでなくモータ部側も常に尿素水に浸される。その結果、例えば軸受など、モータ部側の摺動部における尿素の析出が低減される。したがって、ポンプ部だけでなくモータ部の確実な作動を確保することができる。   In the invention according to claim 2, the suction pipe portion is located above the discharge portion from which the urea water is discharged from the pump portion. Thereby, the liquid level position of the urea water remaining in the connection passage is located above the motor unit as well as the pump unit. Therefore, not only the pump unit but also the motor unit side is always immersed in the urea water. As a result, for example, precipitation of urea in a sliding part on the motor part side such as a bearing is reduced. Therefore, it is possible to ensure the reliable operation of the motor unit as well as the pump unit.

請求項３記載の発明では、吸入管部は略Ｓ字形状である。したがって、簡単な構造で吸入管部の一部をポンプ吸入部およびポンプ部よりも上方に位置させることができる。
請求項４記載の発明では、吸入管部は開口部を有する。例えば車両が坂路にあるときなど、尿素水は残存しているにも関わらず、吸入端部から尿素水を吸入できない場合がある。この場合でも、開口部が尿素水に浸っていれば、開口部から尿素水が吸入される。したがって、例えば坂路など尿素水の液面位置が不正になるときでも、尿素水を安定して吸入することができる。 In the invention according to claim 3, the suction pipe portion is substantially S-shaped. Accordingly, a part of the suction pipe portion can be positioned above the pump suction portion and the pump portion with a simple structure.
In the invention according to claim 4, the suction pipe portion has an opening. For example, when the vehicle is on a slope, the urea water may not be sucked from the suction end portion even though the urea water remains. Even in this case, if the opening is immersed in the urea water, the urea water is sucked from the opening. Therefore, urea water can be stably inhaled even when the surface level of urea water becomes incorrect, such as on a slope.

請求項５記載の発明では、開口部は、ポンプ吸入部および吸入端部よりも下方に位置している。そのため、吸入端部よりも尿素水の液面が低下しても、開口部は尿素水に浸っている。これにより、吸入端部から尿素水を吸入できない位置まで液面が低下したときでも、尿素水は開口部から吸入される。したがって、例えば坂路など尿素水の液面位置が不正になるとき、および液面位置が低下したときでも、尿素水を安定して吸入することができる。一方、開口部をポンプ吸入部および吸入端部よりも下方に設けることにより、接続通路の尿素水は開口部から流出する。接続通路の尿素水が流出すると、ポンプ部は尿素水によって十分に浸されない。そこで、開口部に逆止弁を設けることにより、接続通路から外部への尿素水の流出を制限している。したがって、安定した尿素水の吸入を確保と、接続通路からの尿素水の流出の制限とを両立して達成することができる。   In the invention according to claim 5, the opening is located below the pump suction portion and the suction end portion. Therefore, even if the urea water level is lower than the suction end, the opening is immersed in the urea water. Thereby, even when the liquid level is lowered from the suction end to a position where the urea water cannot be sucked, the urea water is sucked from the opening. Therefore, urea water can be stably inhaled even when the liquid level position of urea water is incorrect, such as on a slope, and even when the liquid level position is lowered. On the other hand, by providing the opening below the pump suction part and the suction end, the urea water in the connection passage flows out from the opening. When the urea water in the connection passage flows out, the pump part is not sufficiently immersed in the urea water. Therefore, by providing a check valve in the opening, the outflow of urea water from the connection passage to the outside is limited. Therefore, it is possible to achieve both the securing of stable urea water suction and the restriction of the outflow of urea water from the connection passage.

請求項６記載の発明では、尿素水タンクにおける尿素水の液面位置は液面センサによって検出される。制御部は、液面センサによって検出した尿素水の液面位置が吸入端部よりも低下すると、モータ部への通電およびインジェクタからの尿素水の噴射を停止する。これにより、尿素水の液面が低下したとき、尿素水ポンプから尿素水が吐出されず、ポンプ部および接続通路には尿素水が確実に残存する。したがって、液面位置が低下したまま放置されても、尿素の結晶の析出が低減され、ポンプ部の確実な作動および尿素水の供給を確保することができる。   In the invention described in claim 6, the liquid level position of the urea water in the urea water tank is detected by the liquid level sensor. When the urea water level detected by the liquid level sensor is lower than the suction end, the control unit stops energizing the motor unit and injecting urea water from the injector. Thereby, when the liquid level of urea water falls, urea water is not discharged from a urea water pump, and urea water remains reliably in a pump part and a connection channel. Therefore, even if the liquid level position is left lowered, precipitation of urea crystals is reduced, and a reliable operation of the pump unit and supply of urea water can be ensured.

以下、本発明の尿素水ポンプを適用した尿素水噴射システムの複数の実施形態を図面に基づいて説明する。なお、複数の実施形態において実質的に同一の構成部位には同一の符号を付し、説明を省略する。
（第１実施形態）
本発明の第１実施形態による尿素水噴射システムを図１に示す。尿素水噴射システム１０は、内燃機関の排気に尿素水を噴射する。内燃機関としては、例えばガソリンエンジンやディーゼルエンジンなどのピストンエンジン、あるいはガスタービンエンジンなど任意のエンジンを適用することができる。尿素水噴射システム１０は、尿素水タンク１１、液面センサ１２、インジェクタ１３、尿素水ポンプ１４および制御部１５などを有している。 Hereinafter, a plurality of embodiments of a urea water injection system to which a urea water pump of the present invention is applied will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
A urea water injection system according to a first embodiment of the present invention is shown in FIG. The urea water injection system 10 injects urea water into the exhaust gas of the internal combustion engine. As the internal combustion engine, for example, a piston engine such as a gasoline engine or a diesel engine, or an arbitrary engine such as a gas turbine engine can be applied. The urea water injection system 10 includes a urea water tank 11, a liquid level sensor 12, an injector 13, a urea water pump 14, a control unit 15, and the like.

尿素水タンク１１は、インジェクタ１３から噴射される尿素水を貯える。液面センサ１２は、尿素水タンク１１に貯えられている尿素水の液面位置を検出する。液面センサ１２は、尿素水タンク１１に設けられている。液面センサ１２は、検出した尿素水の液面位置を電気信号として制御部１５へ出力する。インジェクタ１３は、図示しない内燃機関の排気管部１６に設けられている。排気管部１６は、排気通路１７を形成している。排気管部１６に設けられているインジェクタ１３は、排気通路１７を流れる排気に尿素水を噴射する。インジェクタ１３は、図示しない電磁弁を有している。この電磁弁は、制御部１５から出力された駆動信号に基づいて開閉する。電磁弁が開閉することにより、インジェクタ１３は尿素水ポンプ１４から供給された尿素水の噴射を断続する。インジェクタ１３から噴射された尿素水は、排気通路１７を流れる排気に混合された後、排気通路１７に設けられた図示しないＮＯｘ還元触媒に流入する。排気に含まれるＮＯｘは、ＮＯｘ還元触媒において尿素水と反応し、窒素（Ｎ２）および水（Ｈ２Ｏ）を生成する。 The urea water tank 11 stores urea water injected from the injector 13. The liquid level sensor 12 detects the level position of the urea water stored in the urea water tank 11. The liquid level sensor 12 is provided in the urea water tank 11. The liquid level sensor 12 outputs the detected liquid level position of the urea water to the control unit 15 as an electric signal. The injector 13 is provided in an exhaust pipe portion 16 of an internal combustion engine (not shown). The exhaust pipe portion 16 forms an exhaust passage 17. An injector 13 provided in the exhaust pipe section 16 injects urea water into the exhaust gas flowing through the exhaust passage 17. The injector 13 has a solenoid valve (not shown). This electromagnetic valve opens and closes based on the drive signal output from the control unit 15. The injector 13 intermittently injects the urea water supplied from the urea water pump 14 by opening and closing the solenoid valve. The urea water injected from the injector 13 is mixed with the exhaust gas flowing through the exhaust passage 17 and then flows into a NOx reduction catalyst (not shown) provided in the exhaust passage 17. NOx contained in the exhaust gas reacts with urea water in the NOx reduction catalyst to generate nitrogen (N 2 ) and water (H 2 O).

尿素水ポンプ１４は、尿素水タンク１１に収容されている。尿素水ポンプ１４は、ポンプ部２１およびモータ部２２で構成されている。ポンプ部２１は、ケーシング２３および回転部材としてのインペラ２４を有している。ケーシング２３は、内側にインペラ２４を収容するポンプ通路２５を形成している。ポンプ通路２５は、一方がケーシング２３に設けられているポンプ吸入部２６に接続し、他方がモータ部２２に接続している。インペラ２４は、円板状に形成され、外周側の端部に図示しないはね溝を有している。インペラ２４が回転すると、ポンプ通路２５に吸入された尿素水は加圧される。加圧された尿素水は、ケーシング２３に設けられているポンプ吐出部２７からモータ部２２側へ吐出される。ケーシング２３とインペラ２４との間には、わずかなクリアランスが設けられている。これにより、インペラ２４は、ポンプ通路２５においてケーシング２３と摺動しながら回転する。   The urea water pump 14 is accommodated in the urea water tank 11. The urea water pump 14 includes a pump unit 21 and a motor unit 22. The pump unit 21 includes a casing 23 and an impeller 24 as a rotating member. The casing 23 forms a pump passage 25 that houses the impeller 24 inside. One of the pump passages 25 is connected to a pump suction part 26 provided in the casing 23, and the other is connected to the motor part 22. The impeller 24 is formed in a disk shape, and has a notch (not shown) in the outer peripheral end. When the impeller 24 rotates, the urea water sucked into the pump passage 25 is pressurized. The pressurized urea water is discharged from the pump discharge portion 27 provided in the casing 23 to the motor portion 22 side. A slight clearance is provided between the casing 23 and the impeller 24. Thereby, the impeller 24 rotates while sliding with the casing 23 in the pump passage 25.

モータ部２２は、シャフト３１とともに回転する回転子３２、および回転子３２の外周側で対向する固定子３３とを有している。なお、モータ部２２の構成は、本明細書に記載した例に関わらず、例えば直流モータあるいは交流モータなど任意の構成を採用することができる。シャフト３１は、軸方向の端部にインペラ２４が設けられている。モータ部２２に通電することによりシャフト３１が回転すると、シャフト３１とともにインペラ２４が回転する。モータ部２２の回転子３２および固定子３３は、ケーシング２３に収容されている。ケーシング２３とモータ部２２との間には、ポンプ部２１から吐出された尿素水が流れる吐出通路３４が形成される。また、ケーシング２３は、ポンプ部２１とは反対側の端部に吐出部３５を有している。吐出部３５は、供給配管部３６を経由してインジェクタ１３に接続している。これにより、ポンプ部２１のポンプ吐出部２７から吐出された尿素水は、吐出通路３４を経由して吐出部３５から尿素水ポンプ１４の外部へ吐出される。尿素水ポンプ１４から吐出された尿素水は、供給配管部３６を経由してインジェクタ１３へ供給される。   The motor unit 22 includes a rotor 32 that rotates together with the shaft 31, and a stator 33 that faces the outer periphery of the rotor 32. In addition, the structure of the motor part 22 can employ | adopt arbitrary structures, such as a direct current motor or an alternating current motor, for example irrespective of the example described in this specification. The shaft 31 is provided with an impeller 24 at an end portion in the axial direction. When the shaft 31 rotates by energizing the motor unit 22, the impeller 24 rotates together with the shaft 31. The rotor 32 and the stator 33 of the motor unit 22 are accommodated in the casing 23. A discharge passage 34 through which the urea water discharged from the pump unit 21 flows is formed between the casing 23 and the motor unit 22. In addition, the casing 23 has a discharge portion 35 at an end opposite to the pump portion 21. The discharge part 35 is connected to the injector 13 via the supply piping part 36. As a result, the urea water discharged from the pump discharge portion 27 of the pump portion 21 is discharged from the discharge portion 35 to the outside of the urea water pump 14 via the discharge passage 34. The urea water discharged from the urea water pump 14 is supplied to the injector 13 via the supply piping unit 36.

制御部１５は、図示しないＣＰＵ、ＲＯＭおよびＲＡＭを有するマイクロコンピュータで構成されている。制御部１５には、回転数センサ４１およびアクセルセンサ４２から電気信号が入力される。回転数センサ４１は、図示しない内燃機関の回転数を検出し、検出した回転数を電気信号として制御部１５へ出力する。また、アクセルセンサ４２は、図示しないアクセルペダルの開度を検出し、検出したアクセルペダルの開度を電気信号として制御部１５へ出力する。一方、制御部１５は、インジェクタ１３の図示しない電磁弁および尿素水ポンプ１４のモータ部２２に接続している。制御部１５は、上述のようにインジェクタ１３の電磁弁に対し、尿素水の噴射時期および噴射期間に対応する駆動信号を出力する。また、制御部１５は、モータ部２２への通電を制御する。   The control unit 15 is composed of a microcomputer having a CPU, ROM and RAM (not shown). Electrical signals are input to the control unit 15 from the rotation speed sensor 41 and the accelerator sensor 42. The rotation speed sensor 41 detects the rotation speed of an internal combustion engine (not shown) and outputs the detected rotation speed to the control unit 15 as an electric signal. Further, the accelerator sensor 42 detects the opening of an accelerator pedal (not shown), and outputs the detected opening of the accelerator pedal to the control unit 15 as an electric signal. On the other hand, the control unit 15 is connected to a solenoid valve (not shown) of the injector 13 and a motor unit 22 of the urea water pump 14. As described above, the control unit 15 outputs a drive signal corresponding to the injection timing and the injection period of the urea water to the electromagnetic valve of the injector 13. The control unit 15 controls energization to the motor unit 22.

制御部１５は、アクセルセンサ４２で検出したアクセルペダルの開度に基づいて内燃機関の負荷を検出する。制御部１５は、検出した内燃機関の負荷および回転数センサ４１で検出した内燃機関の回転数から、尿素水の噴射タイミングおよび噴射量を算出する。制御部１５は、算出した尿素水の噴射タイミングおよび噴射量に基づいてインジェクタ１３の電磁弁へ出力する駆動信号を生成するとともに、尿素水ポンプ１４の駆動量を制御する。また、制御部１５は、液面センサ１２から出力された電気信号に基づいて、尿素水タンク１１に貯えられている尿素水の液面位置を検出する。   The control unit 15 detects the load of the internal combustion engine based on the accelerator pedal opening detected by the accelerator sensor 42. The control unit 15 calculates the injection timing and the injection amount of urea water from the detected load of the internal combustion engine and the rotational speed of the internal combustion engine detected by the rotational speed sensor 41. The control unit 15 generates a drive signal to be output to the electromagnetic valve of the injector 13 based on the calculated urea water injection timing and injection amount, and controls the drive amount of the urea water pump 14. Further, the control unit 15 detects the liquid level position of the urea water stored in the urea water tank 11 based on the electric signal output from the liquid level sensor 12.

次に、上記の構成による尿素水ポンプ１４について詳細に説明する。
尿素水ポンプ１４は、吸入管部５０を備えている。吸入管部５０は、筒状に形成され、一方の端部が尿素水ポンプ１４のポンプ吸入部２６に接続している。吸入管部５０の他方の端部は、フィルタ５１を経由して尿素水タンク１１の内側に開口する吸入端部５２を形成している。吸入管部５０は、吸入端部５２とポンプ吸入部２６とを接続する接続通路５３を形成している。フィルタ５１は、接続通路５３へ吸入される尿素水に含まれる異物を捕集する。 Next, the urea water pump 14 having the above configuration will be described in detail.
The urea water pump 14 includes a suction pipe unit 50. The suction pipe portion 50 is formed in a cylindrical shape, and one end thereof is connected to the pump suction portion 26 of the urea water pump 14. The other end portion of the suction pipe portion 50 forms a suction end portion 52 that opens to the inside of the urea water tank 11 via the filter 51. The suction pipe portion 50 forms a connection passage 53 that connects the suction end portion 52 and the pump suction portion 26. The filter 51 collects foreign substances contained in the urea water sucked into the connection passage 53.

吸入管部５０は、略Ｓ字形状に形成されている。詳細には、吸入管部５０は、重力方向においてＳ字形状の上下端を横倒しにした形状である。これにより、吸入管部５０は、ポンプ吸入部２６と吸入端部５２のフィルタ５１までの間に、上湾曲部５４および下湾曲部５５を有する。上湾曲部５４は、重力方向においてポンプ吸入部２６および吸入端部５２よりも上方に位置している。下湾曲部５５は、重力方向においてポンプ吸入部２６の下方に位置している。   The suction pipe portion 50 is formed in a substantially S shape. Specifically, the suction pipe portion 50 has a shape in which the upper and lower ends of the S shape are laid sideways in the direction of gravity. As a result, the suction pipe section 50 has an upper curved section 54 and a lower curved section 55 between the pump suction section 26 and the filter 51 at the suction end section 52. The upper curved portion 54 is located above the pump suction portion 26 and the suction end portion 52 in the direction of gravity. The lower curved portion 55 is located below the pump suction portion 26 in the direction of gravity.

上湾曲部５４は、重力方向においてポンプ部２１よりも上方に位置している。詳細には、上湾曲部５４は、ポンプ部２１のポンプ吐出部２７よりも上方に位置している。このように、吸入管部５０は、少なくとも一部すなわち上湾曲部５４がポンプ部２１よりも上方に位置している。そのため、尿素水タンク１１に貯えられている尿素水の液面位置が低下しても、接続通路５３では液面位置が吸入管部５０の上湾曲部５４の下端５６まで維持される。これにより、尿素水ポンプ１４の内側では、この吸入管部５０の上湾曲部５４の下端５６に相当する高さまで尿素水が貯えられる。したがって、尿素水タンク１１における尿素水の液面位置に関わらず、ポンプ部２１は尿素水に浸される。なお、上湾曲部５４の下端５６の位置は、ポンプ吐出部２７の上方に限らず、ケーシング２３とインペラ２４との摺動部分よりも上方であればよい。すなわち、尿素水タンク１１における尿素水の液面位置に関わらず、ケーシング２３とインペラ２４との摺動部分が尿素水に浸されるように上湾曲部５４の下端５６の位置を設定すればよい。   The upper curved portion 54 is located above the pump portion 21 in the direction of gravity. Specifically, the upper bending portion 54 is located above the pump discharge portion 27 of the pump portion 21. Thus, at least a part of the suction pipe portion 50, that is, the upper curved portion 54 is located above the pump portion 21. Therefore, even if the liquid level position of the urea water stored in the urea water tank 11 is lowered, the liquid level position is maintained up to the lower end 56 of the upper curved portion 54 of the suction pipe section 50 in the connection passage 53. Thereby, the urea water is stored inside the urea water pump 14 to a height corresponding to the lower end 56 of the upper curved portion 54 of the suction pipe portion 50. Therefore, the pump unit 21 is immersed in the urea water regardless of the liquid level position of the urea water in the urea water tank 11. Note that the position of the lower end 56 of the upper bending portion 54 is not limited to the position above the pump discharge portion 27 but may be any position above the sliding portion between the casing 23 and the impeller 24. That is, the position of the lower end 56 of the upper curved portion 54 may be set so that the sliding portion between the casing 23 and the impeller 24 is immersed in the urea water regardless of the liquid level position of the urea water in the urea water tank 11. .

次に、上記の構成による尿素水噴射システム１０の作動について説明する。
内燃機関の運転が開始され、排気通路１７におけるＮＯｘの濃度が所定値以上になると、制御部１５はインジェクタ１３から尿素水の噴射を実施する。排気通路１７におけるＮＯｘの濃度は、内燃機関の燃料の噴射量すなわち内燃機関の負荷に依存する。そこで、制御部１５は、アクセルセンサ４２で検出したアクセルペダルの開度および回転数センサ４１で検出した内燃機関の回転数から噴射する尿素水の量を算出する。また、制御部１５は、尿素水を噴射するタイミングも算出する。制御部１５は、尿素水の噴射量および噴射タイミングを算出すると、算出した値に基づいてインジェクタ１３に駆動信号を出力する。インジェクタ１３は、駆動信号により電磁弁が駆動され、尿素水の噴射が断続される。インジェクタ１３は、排気通路１７を流れる排気に尿素水を噴射する。噴射された尿素水は、排気通路１７を流れる排気に混合された後、ＮＯｘ還元触媒へ流入する。排気に含まれるＮＯｘは、ＮＯｘ還元触媒で尿素とともに窒素および水へ分解される。 Next, the operation of the urea water injection system 10 having the above configuration will be described.
When the operation of the internal combustion engine is started and the concentration of NOx in the exhaust passage 17 becomes a predetermined value or more, the control unit 15 performs urea water injection from the injector 13. The concentration of NOx in the exhaust passage 17 depends on the fuel injection amount of the internal combustion engine, that is, the load on the internal combustion engine. Therefore, the control unit 15 calculates the amount of urea water to be injected from the opening of the accelerator pedal detected by the accelerator sensor 42 and the rotational speed of the internal combustion engine detected by the rotational speed sensor 41. Moreover, the control part 15 also calculates the timing which injects urea water. When calculating the injection amount and the injection timing of the urea water, the control unit 15 outputs a drive signal to the injector 13 based on the calculated value. In the injector 13, the electromagnetic valve is driven by a drive signal, and urea water injection is intermittently performed. The injector 13 injects urea water into the exhaust flowing through the exhaust passage 17. The injected urea water is mixed with the exhaust gas flowing through the exhaust passage 17 and then flows into the NOx reduction catalyst. NOx contained in the exhaust gas is decomposed into nitrogen and water together with urea by the NOx reduction catalyst.

また、制御部１５は、インジェクタ１３からの尿素水の噴射にともない尿素水ポンプ１４の駆動を制御する。制御部１５は、算出されたインジェクタ１３からの尿素水噴射量に基づいて尿素水ポンプ１４の駆動すなわち回転数を制御する。尿素水ポンプ１４は、制御部１５からの通電によってモータ部２２のシャフト３１が回転する。シャフト３１の回転によってインペラ２４が回転し、ポンプ通路２５における尿素水を加圧する。インペラ２４が回転すると、ポンプ通路２５の圧力は低下する。そのため、吸入端部５２から吸入された尿素水は、接続通路５３およびポンプ吸入部２６を経由してポンプ通路２５へ流入する。インペラ２４の回転によってポンプ通路２５で加圧された尿素水は、ポンプ吐出部２７、吐出通路３４、吐出部３５および供給配管部３６を経由してインジェクタ１３へ供給される。   Further, the control unit 15 controls the driving of the urea water pump 14 as the urea water is injected from the injector 13. The control unit 15 controls the drive of the urea water pump 14, that is, the rotation speed, based on the calculated urea water injection amount from the injector 13. In the urea water pump 14, the shaft 31 of the motor unit 22 is rotated by energization from the control unit 15. The impeller 24 is rotated by the rotation of the shaft 31 to pressurize the urea water in the pump passage 25. When the impeller 24 rotates, the pressure in the pump passage 25 decreases. Therefore, the urea water sucked from the suction end portion 52 flows into the pump passage 25 via the connection passage 53 and the pump suction portion 26. The urea water pressurized in the pump passage 25 by the rotation of the impeller 24 is supplied to the injector 13 via the pump discharge portion 27, the discharge passage 34, the discharge portion 35 and the supply piping portion 36.

以上説明した第１実施形態では、略Ｓ字形状に形成された吸入管部５０は、最上部となる上湾曲部５４がポンプ部２１のポンプ吐出部２７よりも上方に位置している。そのため、尿素水タンク１１における尿素水の液面が低下しても、吸入管部５０の上湾曲部５４よりもポンプ吸入部２６側、およびポンプ部２１では尿素水の液面位置が上湾曲部５４の下端５６と同一の高さに位置している。これにより、尿素水タンク１１における尿素水の液面位置に関わらず、ポンプ部２１は尿素水に浸されている。例えば尿素水の蒸発などによって尿素水タンク１１内の液面位置が低下したまま放置されても、ポンプ部２１は尿素水に浸されている。その結果、ポンプ部２１のインペラ２４およびケーシング２３は、尿素水に浸される。インペラ２４およびケーシング２３を尿素水に浸すことにより、インペラ２４およびケーシング２３と空気との接触は回避される。その結果、インペラ２４やケーシング２３への尿素の結晶の析出は低減される。したがって、析出した結晶によるポンプ部２１の摩耗、損傷あるいは固着を低減することができ、ポンプ部２１の確実な作動を確保することができる。   In the first embodiment described above, in the suction pipe portion 50 formed in a substantially S shape, the upper curved portion 54 that is the uppermost portion is located above the pump discharge portion 27 of the pump portion 21. Therefore, even if the liquid level of the urea water in the urea water tank 11 decreases, the liquid level position of the urea water in the pump suction part 26 side and the pump part 21 is higher than the upper curved part 54 of the suction pipe part 50. It is located at the same height as the lower end 56 of 54. Accordingly, the pump unit 21 is immersed in the urea water regardless of the liquid level position of the urea water in the urea water tank 11. For example, even if the liquid level in the urea water tank 11 is lowered due to evaporation of urea water or the like, the pump unit 21 is immersed in the urea water. As a result, the impeller 24 and the casing 23 of the pump unit 21 are immersed in the urea water. By immersing the impeller 24 and the casing 23 in urea water, contact between the impeller 24 and the casing 23 and air is avoided. As a result, precipitation of urea crystals on the impeller 24 and the casing 23 is reduced. Therefore, wear, damage or sticking of the pump part 21 due to the precipitated crystals can be reduced, and a reliable operation of the pump part 21 can be ensured.

（変形例）
上記の構成による尿素水噴射システム１０では、制御部１５は液面センサ１２によって尿素水タンク１１における尿素水の液面位置を検出している。そこで、制御部１５は、液面センサ１２で検出した尿素水の液面位置が吸入端部５２であるフィルタ５１の下端部よりも低いとき、インジェクタ１３による尿素水の噴射および尿素水ポンプ１４の作動を停止させる構成としてもよい。尿素水の液面位置がフィルタ５１の下端部よりも低いとき、インジェクタ１３および尿素水ポンプ１４の作動を継続すると、ポンプ部２１および接続通路５３に残存する尿素水はインジェクタ１３側へ吐出される。そのため、ポンプ部２１に残存する尿素水の液面が低下する。そこで、液面センサ１２で検出した尿素水の液面位置によってインジェクタ１３および尿素水ポンプ１４の作動を停止させることにより、尿素水のポンプ部２１への確実な残存が図られる。また、蒸発などにより尿素水ポンプ１４の液面位置が低下したときでも、尿素水ポンプ１４およびインジェクタ１３の作動による尿素水の消費が回避される。そのため、ポンプ部２１は尿素水へ浸された状態が維持される。したがって、液面位置が低下したり、液面位置が低下したまま放置されたりした場合でも、ポンプ部２１への尿素の結晶の析出が低減され、ポンプ部２１の確実な作動および尿素水の供給を確保することができる。 (Modification)
In the urea water injection system 10 configured as described above, the control unit 15 detects the liquid level position of the urea water in the urea water tank 11 by the liquid level sensor 12. Therefore, when the liquid level position of the urea water detected by the liquid level sensor 12 is lower than the lower end portion of the filter 51 that is the suction end 52, the control unit 15 injects the urea water by the injector 13 and the urea water pump 14. It is good also as a structure which stops operation | movement. When the urea water level is lower than the lower end of the filter 51, if the operation of the injector 13 and the urea water pump 14 is continued, the urea water remaining in the pump portion 21 and the connection passage 53 is discharged to the injector 13 side. . Therefore, the liquid level of the urea water remaining in the pump unit 21 is lowered. Accordingly, by stopping the operation of the injector 13 and the urea water pump 14 based on the liquid level position of the urea water detected by the liquid level sensor 12, the urea water can be reliably left in the pump unit 21. Even when the liquid level of the urea water pump 14 is lowered due to evaporation or the like, consumption of the urea water due to the operation of the urea water pump 14 and the injector 13 is avoided. Therefore, the pump unit 21 is maintained in a state immersed in urea water. Therefore, even when the liquid surface position is lowered or the liquid surface position is left lowered, precipitation of urea crystals on the pump unit 21 is reduced, and the pump unit 21 is reliably operated and urea water is supplied. Can be secured.

（第２実施形態）
本発明の第２実施形態による尿素水ポンプを適用した尿素水噴射システムを図２に示す。
第２実施形態による尿素水ポンプ１４の場合、吸入管部１５０の上湾曲部５４が吐出部３５よりも重力方向において上方に位置している。そのため、尿素水タンク１１の液面位置が低下したとき、ポンプ部２１だけでなくモータ部２２も尿素水に浸される。詳細には、吸入管部１５０の上湾曲部５４の下端５６は、モータ部２２のポンプ部２１とは反対側に設けられている吐出部３５よりも上方に位置している。そのため、尿素水タンク１１の液面位置が低下したとき、ポンプ部２１のポンプ通路２５だけでなくモータ部２２の吐出通路３４も尿素水に浸される。 (Second Embodiment)
A urea water injection system to which a urea water pump according to a second embodiment of the present invention is applied is shown in FIG.
In the case of the urea water pump 14 according to the second embodiment, the upper curved portion 54 of the suction pipe portion 150 is located above the discharge portion 35 in the gravity direction. Therefore, when the liquid level position of the urea water tank 11 is lowered, not only the pump unit 21 but also the motor unit 22 are immersed in the urea water. Specifically, the lower end 56 of the upper curved portion 54 of the suction pipe portion 150 is positioned above the discharge portion 35 provided on the opposite side of the motor portion 22 from the pump portion 21. Therefore, when the liquid level position of the urea water tank 11 is lowered, not only the pump passage 25 of the pump portion 21 but also the discharge passage 34 of the motor portion 22 is immersed in the urea water.

第２実施形態では、モータ部２２の吐出通路３４も尿素水に浸される。そのため、モータ部２２を構成する回転子３２と固定子３３との間、およびシャフト３１と図示しない軸受との間における尿素の結晶の析出が低減される。したがって、ポンプ部２１だけでなくモータ部２２の摩耗、損傷あるいは固着を低減することができ、ポンプ部２１の確実な作動を確保することができる。   In the second embodiment, the discharge passage 34 of the motor unit 22 is also immersed in the urea water. Therefore, precipitation of urea crystals between the rotor 32 and the stator 33 constituting the motor unit 22 and between the shaft 31 and a bearing (not shown) is reduced. Therefore, not only the pump part 21 but also the motor part 22 can be reduced in wear, damage or sticking, and a reliable operation of the pump part 21 can be ensured.

（第３実施形態）
本発明の第３実施形態による尿素水ポンプを適用した尿素水噴射システムを図３に示す。
第３実施形態による尿素水ポンプ１４の場合、吸入管部２５０の下湾曲部５５はポンプ吸入部２６および吸入端部５２よりも下方に位置している。すなわち、吸入管部２５０の下湾曲部５５の下端５７は、吸入端部５２のフィルタ５１の下端よりも下方に位置している。また、吸入管部２５０は、図４に示すようにこの下湾曲部５５の下端５７に板厚方向に貫く開口部５８を有している。吸入管部２５０の開口部５８には、逆止弁５９が設けられている。第３実施例の場合、逆止弁５９は接続通路５３と外部との圧力差によって開口部５８を開閉する球状部材である。逆止弁５９は、吸入管部２５０の外部から接続通路５３への尿素水の流れを許容するとともに、接続通路５３から吸入管部２５０の外部への尿素水の流れを制限する。 (Third embodiment)
A urea water injection system to which a urea water pump according to a third embodiment of the present invention is applied is shown in FIG.
In the case of the urea water pump 14 according to the third embodiment, the lower curved portion 55 of the suction pipe portion 250 is located below the pump suction portion 26 and the suction end portion 52. That is, the lower end 57 of the lower curved portion 55 of the suction pipe portion 250 is located below the lower end of the filter 51 of the suction end portion 52. Further, as shown in FIG. 4, the suction pipe portion 250 has an opening 58 that penetrates in the thickness direction at the lower end 57 of the lower curved portion 55. A check valve 59 is provided in the opening 58 of the suction pipe portion 250. In the case of the third embodiment, the check valve 59 is a spherical member that opens and closes the opening 58 by a pressure difference between the connection passage 53 and the outside. The check valve 59 allows the flow of urea water from the outside of the suction pipe portion 250 to the connection passage 53 and restricts the flow of urea water from the connection passage 53 to the outside of the suction pipe portion 250.

例えば尿素水タンク１１における尿素水の残量が少なく、車両が傾斜地あるいは坂路を走行または停車しているとき、図３に示すように尿素水タンク１１における尿素水の液面位置は傾斜した不正な状態となる。また、車両の走行時の揺れなどによっても、尿素水タンク１１に貯えられている尿素水の液面位置は不正な状態となる。このとき、尿素水タンク１１に尿素水が残存しているにも関わらず、尿素水の液面位置がフィルタ５１の下端よりも下方になると、尿素水ポンプ１４は尿素水の吸入が困難になる。第３実施形態では、吸入管部２５０の最下部となる下湾曲部５５に開口部５８が設けられている。下湾曲部５５は、フィルタ５１よりも下方にある。そのため、フィルタ５１が尿素水に浸っていない場合でも、下湾曲部５５は尿素水に浸っている。その結果、尿素水の液面が不正な状態となりフィルタ５１からの尿素水の吸入が困難な場合でも、尿素水ポンプ１４を作動したとき尿素水は開口部５８から吸入される。   For example, when the amount of urea water in the urea water tank 11 is small and the vehicle is traveling or stopping on a slope or a slope, the liquid level position of the urea water in the urea water tank 11 is inclined and illegal as shown in FIG. It becomes a state. Further, the liquid level position of the urea water stored in the urea water tank 11 is also in an incorrect state due to the shaking of the vehicle during traveling. At this time, when the urea water level is below the lower end of the filter 51 even though the urea water remains in the urea water tank 11, the urea water pump 14 has difficulty in sucking the urea water. . In the third embodiment, an opening 58 is provided in the lower curved portion 55 that is the lowermost portion of the suction pipe portion 250. The lower curved portion 55 is below the filter 51. For this reason, even when the filter 51 is not immersed in urea water, the lower curved portion 55 is immersed in urea water. As a result, even when the urea water level is incorrect and it is difficult to suck urea water from the filter 51, urea water is sucked from the opening 58 when the urea water pump 14 is operated.

一方、開口部５８を設けることにより、吸入管部５０に残存する尿素水は開口部５８を経由して外部へ流出するおそれがある。そこで、開口部５８には、逆止弁５９を設けている。逆止弁５９は、接続通路５３から外部への尿素水の流出を制限する。そのため、モータ部２２が停止されると、逆止弁５９は開口部５８を閉塞し、外部への尿素水の流出が低減される。これにより、尿素水タンク１１における尿素水の液面位置が低下しているとき、モータ部２２が停止されても、接続通路５３には尿素水が残存する。したがって、安定した尿素水の吸入を確保と、接続通路５３からの尿素水の流出の制限とを両立して達成することができる。   On the other hand, the provision of the opening 58 may cause the urea water remaining in the suction pipe portion 50 to flow outside through the opening 58. Therefore, a check valve 59 is provided in the opening 58. The check valve 59 restricts the outflow of urea water from the connection passage 53 to the outside. Therefore, when the motor unit 22 is stopped, the check valve 59 closes the opening 58, and the outflow of urea water to the outside is reduced. Thereby, when the liquid level position of the urea water in the urea water tank 11 is lowered, the urea water remains in the connection passage 53 even if the motor unit 22 is stopped. Therefore, it is possible to achieve both the securing of stable urea water suction and the restriction of the outflow of urea water from the connection passage 53.

（その他の実施形態）
以上説明した複数の実施形態では、吸入管部５０、１５０、２５０を略Ｓ字形状に形成する例について説明した。しかし、吸入管部５０、１５０、２５０は、少なくとも一部がポンプ部２１よりも上方に位置する構成であれば、略Ｓ字形状に限らない。また、第３実施形態で説明したように吸入管部２５０に形成する開口部５８の位置は、吸入管部２５０の下湾曲部５５の下端５７に限らない。開口部５８は、ポンプ吸入部２６および吸入端部５２よりも下方に位置する部分であれば吸入管部５０の任意の部分に設けることができる。 (Other embodiments)
In the plurality of embodiments described above, examples in which the suction pipe portions 50, 150, 250 are formed in a substantially S shape have been described. However, the suction pipe portions 50, 150, 250 are not limited to a substantially S shape as long as at least a part thereof is positioned above the pump portion 21. Further, as described in the third embodiment, the position of the opening 58 formed in the suction pipe portion 250 is not limited to the lower end 57 of the lower curved portion 55 of the suction pipe portion 250. The opening 58 can be provided in any part of the suction pipe part 50 as long as it is located below the pump suction part 26 and the suction end part 52.

また、開口部５８には、フィルタ５１と同様にフィルタを設けてもよい。これにより、開口部５８から接続通路５３へ吸入される尿素水は、開口部５８に設けられたフィルタによって異物が捕集される。したがって、尿素水ポンプ１４のポンプ部２１において、異物による破損、摩耗あるいは固着などを低減することができる。
以上説明した各実施形態では、それぞれ個別に適用する例について説明した。しかし、複数の実施形態を組み合わせて適用してもよい。また、第２実施形態および第３実施形態に第１実施形態の変形例を組み合わせて適用してもよい。 Further, the opening 58 may be provided with a filter in the same manner as the filter 51. Thereby, the urea water sucked into the connection passage 53 from the opening 58 is collected by the filter provided in the opening 58. Therefore, in the pump part 21 of the urea water pump 14, breakage, wear or sticking due to foreign matters can be reduced.
In each embodiment described above, the example applied individually was demonstrated. However, a plurality of embodiments may be applied in combination. Moreover, you may apply combining the modification of 1st Embodiment with 2nd Embodiment and 3rd Embodiment.

以上説明した本発明は、上記実施形態に限定されるものではなく、その要旨を逸脱しない範囲で種々の実施形態に適用可能である。   The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

本発明の第１実施形態による尿素水ポンプを適用した尿素水噴射システムを示す模式図The schematic diagram which shows the urea water injection system to which the urea water pump by 1st Embodiment of this invention is applied. 本発明の第２実施形態による尿素水ポンプを適用した尿素水噴射システムを示す模式図The schematic diagram which shows the urea water injection system to which the urea water pump by 2nd Embodiment of this invention is applied. 本発明の第３実施形態による尿素水ポンプを適用した尿素水噴射システムを示す模式図The schematic diagram which shows the urea water injection system to which the urea water pump by 3rd Embodiment of this invention is applied. 本発明の第３実施形態による尿素水ポンプの吸入管部において下湾曲部を拡大した断面図Sectional drawing which expanded the lower curved part in the suction pipe part of the urea water pump by 3rd Embodiment of this invention

符号の説明Explanation of symbols

図面中、１０は尿素水噴射システム、１１は尿素水タンク、１２は液面センサ、１３はインジェクタ、１４は尿素水ポンプ、１５は制御部、１７は排気通路、２１はポンプ部、２２はモータ部、２６はポンプ吸入部、３５は吐出部、５０、１５０、２５０は吸入管部、５２は吸入端部、５３は接続通路、５８は開口部、５９は逆止弁を示す。   In the drawings, 10 is a urea water injection system, 11 is a urea water tank, 12 is a liquid level sensor, 13 is an injector, 14 is a urea water pump, 15 is a control unit, 17 is an exhaust passage, 21 is a pump unit, and 22 is a motor. , 26 is a pump suction part, 35 is a discharge part, 50, 150 and 250 are suction pipe parts, 52 is a suction end part, 53 is a connection passage, 58 is an opening part, and 59 is a check valve.

Claims (6)

ポンプ部と、
前記ポンプ部を駆動するモータ部と、
前記ポンプ部に接続し尿素水を吸入するポンプ吸入部と、
前記ポンプ吸入部に接続され前記ポンプ吸入部とは反対側の吸入端部から吸入された尿素水が前記ポンプ吸入部へ流れる接続通路を形成し、前記接続通路の少なくとも一部が重力方向において前記ポンプ部よりも上方に位置する吸入管部と、
を備えることを特徴とする尿素水ポンプ。 A pump section;
A motor unit for driving the pump unit;
A pump suction part connected to the pump part for sucking urea water;
The urea water that is connected to the pump suction portion and sucked from the suction end opposite to the pump suction portion forms a connection passage through which the urea water flows to the pump suction portion, and at least a part of the connection passage is in the gravity direction in the gravity direction A suction pipe part located above the pump part;
A urea water pump comprising: 前記モータ部の前記ポンプ部とは反対側の端部に設けられ、前記ポンプ部で加圧された尿素水が吐出される吐出部を備え、
前記吸入管部は、前記接続通路の少なくとも一部が重力方向において前記吐出部よりも上方にあることを特徴とする請求項１記載の尿素水ポンプ。 Provided at the end of the motor unit opposite to the pump unit, and provided with a discharge unit for discharging urea water pressurized by the pump unit,
2. The urea water pump according to claim 1, wherein at least part of the connection passage is above the discharge portion in the direction of gravity. 前記吸入管部は、略Ｓ字形状であることを特徴とする請求項１または２記載の尿素水ポンプ。   The urea water pump according to claim 1, wherein the suction pipe portion is substantially S-shaped. 前記吸入管部は、前記ポンプ吸入部と前記吸入端部との間に開口部を有することを特徴とする請求項１、２または３記載の尿素水ポンプ。   The urea water pump according to claim 1, wherein the suction pipe portion has an opening between the pump suction portion and the suction end portion. 前記開口部は、前記ポンプ吸入部および前記吸入端部よりも重力方向下方に位置する部分に設けられ、
前記開口部を開閉可能に設けられ、前記吸入管部の外側から前記接続通路への尿素水の流れを許容し、前記接続通路から前記吸入管部の外側への尿素水の流れを遮断する逆止弁をさらに備えることを特徴とする請求項４記載の尿素水ポンプ。 The opening is provided in a portion located below the pump suction portion and the suction end portion in the direction of gravity,
The opening is provided so as to be openable and closable, and allows reverse flow of urea water from the outside of the suction pipe portion to the connection passage, and blocks the flow of urea water from the connection passage to the outside of the suction pipe portion. The urea water pump according to claim 4, further comprising a stop valve. 請求項１から５のいずれか一項記載の尿素水ポンプと、
前記尿素水ポンプが収容され、尿素水を貯える尿素水タンクと、
前記尿素水タンクに貯えられている尿素水の液面位置を検出する液面センサと、
前記尿素水ポンプから吐出された尿素水を、内燃機関の排気通路を流れる排気に噴射するインジェクタと、
前記液面センサで検出した前記尿素水タンクに貯えられている尿素水の液面位置が重力方向において前記吸入端部よりも下方にあるとき、前記モータ部への通電および前記インジェクタからの尿素水の噴射を停止する制御部と、
を備えることを特徴とする尿素水噴射システム。 A urea water pump according to any one of claims 1 to 5,
A urea water tank that houses the urea water pump and stores urea water;
A liquid level sensor for detecting a liquid level position of urea water stored in the urea water tank;
An injector for injecting urea water discharged from the urea water pump into exhaust flowing through an exhaust passage of an internal combustion engine;
When the liquid level position of the urea water stored in the urea water tank detected by the liquid level sensor is below the suction end in the direction of gravity, the urea water from the injector and the injector is energized. A control unit for stopping the injection of
A urea water injection system comprising:
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KR101220393B1 (en) 2011-09-20 2013-01-09 기아자동차주식회사 Pump structure for urea scr system
CN110841424A (en) * 2019-11-07 2020-02-28 江苏科技大学 Three-section type hypergravity ship tail gas treatment device and working method

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