JP2012002060A - Urea quality diagnostic system - Google Patents

Urea quality diagnostic system Download PDF

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JP2012002060A
JP2012002060A JP2010119861A JP2010119861A JP2012002060A JP 2012002060 A JP2012002060 A JP 2012002060A JP 2010119861 A JP2010119861 A JP 2010119861A JP 2010119861 A JP2010119861 A JP 2010119861A JP 2012002060 A JP2012002060 A JP 2012002060A
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JP5671839B2 (en
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Hirotaka Takahashi
弘隆 高橋
Takeshi Fukuoka
武史 福岡
Tomoyuki Ito
朝幸 伊藤
Yasuo Okamoto
泰雄 岡本
Tatsuo Masuko
達夫 益子
Masanobu Minesawa
正信 嶺澤
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Isuzu Motors Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide an urea quality diagnostic system capable of accurately diagnosing the quality of urea water in an urea tank.SOLUTION: The urea quality diagnostic system detects the concentration and temperature of the urea water 15 in the urea water tank 16 and diagnoses the quality of the urea water. In the urea quality diagnostic system, the lower limit value β of a determinable water temperature is set individually according to the concentration of the urea water. When the detected urea water temperature is higher than the individually set lower limit value β of determinable water temperature, the quality determination of the concentration is performed, and when the detected urea water temperature becomes below the individually set lower limit value β of the determinable water temperature, the quality determination of the concentration is not performed.

Description

本発明は、エンジンの排ガス中のＮＯｘを尿素水を用いて還元するＳＣＲシステムに係り、特にＳＣＲ装置に噴射する尿素水の濃度等の品質を診断するための尿素品質診断システムに関するものである。   The present invention relates to an SCR system for reducing NOx in exhaust gas of an engine using urea water, and more particularly to a urea quality diagnostic system for diagnosing quality such as the concentration of urea water injected into an SCR device.

ディーゼルエンジンの排気ガス中のＮＯｘを浄化するために排ガス浄化システムとして、例えば選択還元触媒（ＳＣＲ）を用いたＳＣＲシステムが開発されている（例えば、特許文献１，２参照）。   In order to purify NOx in exhaust gas of a diesel engine, an SCR system using a selective reduction catalyst (SCR), for example, has been developed as an exhaust gas purification system (see, for example, Patent Documents 1 and 2).

このＳＣＲシステムは、尿素を還元剤として使用し、尿素水をＳＣＲ装置の排気ガス上流に供給し、排気ガスの熱で尿素を加水分解してアンモニアを生成し、このアンモニアによってＳＣＲ触媒上でＮＯｘを還元して浄化するものである。   This SCR system uses urea as a reducing agent, supplies urea water to the exhaust gas upstream of the SCR device, and hydrolyzes urea with the heat of the exhaust gas to generate ammonia, which is used as NOx on the SCR catalyst. Is to reduce and purify.

尿素水はタンクに貯蔵され、所定の濃度（例えば３２．５％）で目標浄化率が達成できるように、エンジン回転数と負荷に応じた尿素噴射量をキャリブレーションしている。   The urea water is stored in the tank, and the urea injection amount corresponding to the engine speed and the load is calibrated so that the target purification rate can be achieved at a predetermined concentration (for example, 32.5%).

ところで、尿素水を補給する際、尿素水が水で薄められたり、水分の蒸発などで濃度が高くなったり、また、塩水などの異質の液体が入れたりすると、浄化性能の低下や最悪装置の故障（噴射ノズルの詰まり等）といった問題が生じる。   By the way, when replenishing urea water, if the urea water is diluted with water, the concentration becomes high due to evaporation of moisture, etc., or if a foreign liquid such as salt water enters, the purification performance deteriorates and the worst equipment Problems such as failure (clogging of the injection nozzle) occur.

この尿素水タンクの尿素濃度や液位や温度を測定する尿素センサとしては、特許文献３に示されるような尿素センサが知られている。この尿素センサは、静電容量で液位を検出し、超音波速度で濃度を検出し、ヒータ抵抗で温度を検出するものである。   As a urea sensor for measuring the urea concentration, liquid level and temperature of this urea water tank, a urea sensor as shown in Patent Document 3 is known. This urea sensor detects a liquid level with a capacitance, detects a concentration with an ultrasonic velocity, and detects a temperature with a heater resistance.

この尿素センサで、尿素水の品質を診断し、濃度異常や液体（塩水など）が入れられたことを検出した場合に、尿素水噴射を禁止し、運転者に警告を発して正規の尿素水の入れ換えを促し、警告が無視されて所定距離走行した時には、エンジンを再始動できなくする措置を取ったりして尿素タンクに正規の尿素水を入れるようにシステムを保護するようにしている。   This urea sensor diagnoses the quality of urea water and detects that the concentration is abnormal or that liquid (salt water, etc.) has been introduced. If the warning is ignored and the vehicle travels a predetermined distance, measures are taken to prevent the engine from being restarted, and the system is protected so that normal urea water is put into the urea tank.

特開２０００−２７６２７号公報JP 2000-27627 A 特開２００５−８３２２３号公報JP 2005-83223 A 特開２００７−４７００６号公報JP 2007-47006 A 特開２００５−２６４９３３号公報JP 2005-264933 A

このように尿素センサで、尿素水の濃度を検出し、所定濃度範囲内にない時は、濃度異常として警告を発するようにするが、濃度の検出は超音波速度で測定するため、その尿素水の温度によって、その検出精度が影響を受ける問題がある。特に、尿素水の凍結温度（−１１℃）以下では尿素水が凍結してしまい正確な濃度診断が行えない。   In this way, the urea sensor detects the concentration of urea water, and when it is not within the predetermined concentration range, a warning is given as an abnormal concentration. However, since the concentration is measured at the ultrasonic speed, the urea water There is a problem that the detection accuracy is affected by the temperature of the. In particular, at a temperature below the freezing temperature of urea water (−11 ° C.), the urea water freezes and accurate concentration diagnosis cannot be performed.

そこで、従来は、尿素水が確実に凍結しない温度（例えば−５℃）以上のときに濃度の診断を行うようにしている（特許文献４）。しかし、濃度が薄い側では、問題は生じないが、濃い側では、正確な濃度測定は行えない問題がある。すなわち、温度閾値を−５℃以上に設定すれば尿素水は凍結しないため濃度の測定はできるものの、尿素の濃度が濃い場合は、温度の低下と共に尿素水が析出してしまい正確な濃度診断が行えなくなる問題がある。   Therefore, conventionally, the concentration is diagnosed when the temperature of the urea water is higher than the temperature at which the aqueous urea does not freeze reliably (for example, −5 ° C.) (Patent Document 4). However, there is no problem on the low density side, but there is a problem that accurate density measurement cannot be performed on the high density side. That is, if the temperature threshold is set to −5 ° C. or higher, the concentration of urea can be measured because it does not freeze. However, if the concentration of urea is high, the concentration of urea decreases as the temperature decreases, and an accurate concentration diagnosis is performed. There is a problem that can not be done.

そこで、本発明の目的は、上記課題を解決し、尿素タンク内の尿素水の品質を的確に診断できる尿素品質診断システムを提供することにある。   Therefore, an object of the present invention is to provide a urea quality diagnosis system that can solve the above-described problems and can accurately diagnose the quality of urea water in a urea tank.

上記目的を達成するために請求項１の発明は、尿素タンク内の尿素水の濃度と温度を検出して、その尿素水の品質を診断する尿素品質診断システムにおいて、尿素水の濃度に応じて判定可能水温下限値を個別に設定し、検出した尿素水温度が、個別に設定された判定可能水温下限値より高いとき濃度の品質判定を行い、前記個別に設定された判定可能水温下限値を下回ったとき濃度の品質判定を行わないようにしたことを特徴とする尿素品質診断システムである。   In order to achieve the above object, a first aspect of the invention relates to a urea quality diagnostic system for detecting the concentration and temperature of urea water in a urea tank and diagnosing the quality of the urea water, according to the concentration of urea water. The lower limit value of the water temperature that can be determined is individually set, and when the detected urea water temperature is higher than the lower limit value of the water temperature that can be individually determined, the quality of the concentration is determined. The urea quality diagnosis system is characterized in that the quality judgment of the concentration is not performed when it falls below.

請求項２の発明は、検出した尿素水の濃度が所定濃度より高いときの判定可能水温下限値を、尿素水の正常濃度上限値で尿素析出が起きない飽和温度以上に設定している請求項１記載の尿素品質診断システムである。   In the invention of claim 2, the lower limit value of the water temperature that can be determined when the detected concentration of urea water is higher than a predetermined concentration is set to a saturation temperature at which urea precipitation does not occur at the normal concentration upper limit value of urea water. 1. The urea quality diagnostic system according to 1.

請求項３の発明は、検出した尿素水の濃度が所定濃度よりも低いときの判定可能水温下限値を、尿素が凍結しない凍結温度以上に設定する請求項１記載の尿素品質診断システムである。   The invention according to claim 3 is the urea quality diagnosis system according to claim 1, wherein the lower limit value of the water temperature that can be determined when the detected concentration of urea water is lower than a predetermined concentration is set to a freezing temperature at which urea does not freeze.

請求項４の発明は、濃度異常と診断したとき、尿素噴射を禁止し、これを運転者に警告するようにした請求項１〜３いずれかに記載の尿素品質診断システムである。   The invention according to claim 4 is the urea quality diagnostic system according to any one of claims 1 to 3, wherein when a concentration abnormality is diagnosed, urea injection is prohibited and a warning is given to the driver.

本発明によれば、尿素タンク内の尿素水の濃度を検出する際に、温度条件を考慮して尿素水の品質を診断することで、的確な品質診断が行えるという優れた効果を発揮するものである。   According to the present invention, when the concentration of urea water in the urea tank is detected, the quality of the urea water is diagnosed in consideration of the temperature condition, thereby exhibiting an excellent effect that an accurate quality diagnosis can be performed. It is.

本発明の一実施の形態を示すシステム図である。It is a system diagram showing an embodiment of the present invention. 本発明の尿素品質診断システムのフローを示す図である。It is a figure which shows the flow of the urea quality diagnostic system of this invention. 本発明において尿素診断を行う際の尿素水の尿素水濃度と尿素温度の状態を示す図である。It is a figure which shows the state of the urea water density | concentration and urea temperature at the time of performing urea diagnosis in this invention. 本発明の尿素品質診断システムの他のフローを示す図である。It is a figure which shows the other flow of the urea quality diagnostic system of this invention.

以下、本発明の好適な一実施の形態を添付図面に基づいて詳述する。   A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

図１において、ディーゼルエンジンの排気管１０には、ＳＣＲ装置１１が接続され、そのＳＣＲ装置１１の上流側に尿素水を噴射する噴射ノズル１２が設けられてＳＣＲシステムが構成される。   In FIG. 1, an SCR device 11 is connected to an exhaust pipe 10 of a diesel engine, and an injection nozzle 12 for injecting urea water is provided on the upstream side of the SCR device 11 to constitute an SCR system.

ＳＣＲ装置１１は、酸化触媒層１３と触媒付セラミックフィルタ１４とからなり、酸化触媒層１３で、排ガス中のＰＭ（パティキュレートマター）中に含まれる炭化水素ＨＣを主とした未燃焼物質（ＳＯＦ）を酸化し、触媒付セラミックフィルタ１４で排ガス中のＰＭを捕集し、さらにその触媒付セラミックフィルタ１４で、尿素水の熱分解で生じたアンモニアとＮＯｘを反応させて脱硝するようになっている。   The SCR device 11 includes an oxidation catalyst layer 13 and a ceramic filter 14 with a catalyst. The oxidation catalyst layer 13 is an unburned substance (SOF) mainly composed of hydrocarbon HC contained in PM (particulate matter) in exhaust gas. ) Is collected, PM in the exhaust gas is collected by the catalyst-equipped ceramic filter 14, and the catalyst-attached ceramic filter 14 reacts with ammonia and NOx generated by the thermal decomposition of urea water for denitration. Yes.

尿素水１５は尿素タンク１６内に貯蔵され、ポンプからなるサプライモジュール１７にて、尿素タンク１６内の尿素水が送液ライン１８を通して吸い上げられ、噴射ノズル１２に供給されて噴射され、余剰の尿素水は、回収ライン１９を通して尿素タンク１６に戻されるようになっている。   The urea water 15 is stored in the urea tank 16, and the urea water in the urea tank 16 is sucked up through the liquid feed line 18 in the supply module 17 including a pump, supplied to the injection nozzle 12, and injected, and excess urea The water is returned to the urea tank 16 through the recovery line 19.

噴射ノズル１２から噴射される尿素水量は、ＤＣＵ（Ｄｏｓｉｎｇ Ｃｏｎｔｒｏｌ Ｕｎｉｔ；噴射弁制御装置）２０により制御される。ＤＣＵ２０は、ＥＣＵ（エンジンコントロールユニット）に接続され、ＥＣＵからのエンジン回転数−負荷と、排気管１０の上流側に設けられた排気温度センサ２１、ＮＯｘセンサ２２の検出値に基づいて噴射する尿素水量を決定し、これに基づいてサプライモジュール１７を制御する。   The amount of urea water injected from the injection nozzle 12 is controlled by a DCU (Dosing Control Unit) 20. The DCU 20 is connected to an ECU (Engine Control Unit) and injects urea based on the engine rotation speed-load from the ECU and the detection values of the exhaust temperature sensor 21 and the NOx sensor 22 provided on the upstream side of the exhaust pipe 10. The amount of water is determined, and the supply module 17 is controlled based on this.

さて、尿素タンク１６には、尿素水１５の濃度と水位と温度を検出する尿素センサ２３が設けられ、この尿素センサ２３の検出値（濃度、水位、温度）がＤＣＵ２０に入力される。   The urea tank 16 is provided with a urea sensor 23 that detects the concentration, water level, and temperature of the urea water 15, and the detected values (concentration, water level, temperature) of the urea sensor 23 are input to the DCU 20.

尿素センサ２３は、基本的には静電容量変化で水位を測定し、超音波速度で濃度を測定し、ヒータ抵抗で温度を測定するものであるが、同時に電気伝導度も測定して塩水などの混入も検出できるものである。この尿素センサ２３は、図示のように水位センサと濃度センサと温度センサを一体化したものでも、或いは個々に水位と濃度と温度を検出するセンサで構成してもいずれでも良い。   The urea sensor 23 basically measures the water level by changing the capacitance, measures the concentration by the ultrasonic velocity, and measures the temperature by the heater resistance. Can also be detected. The urea sensor 23 may be an integrated water level sensor, concentration sensor, and temperature sensor as shown in the figure, or may be configured by a sensor that individually detects the water level, concentration, and temperature.

このＤＣＵ２０は、尿素センサ２３からの温度と濃度の検出値に基づいて、尿素水の品質を診断するようになっている。   The DCU 20 diagnoses the quality of the urea water based on the detected temperature and concentration values from the urea sensor 23.

本発明においては、尿素水の濃度を検出・診断するにあたり、正常か異常かの判定条件に、その時の尿素水の温度条件を加え、濃度の濃い側と薄い側でそれぞれ個別の判定可能水温下限値を設定し、その個別の判定可能水温下限値に応じて的確な品質診断を行うものである。   In the present invention, when detecting and diagnosing the concentration of urea water, the temperature condition of the urea water at that time is added to the determination condition of normal or abnormal, and the water temperature lower limit that can be individually determined for the dark side and the light side A value is set, and an accurate quality diagnosis is performed according to the individual water temperature lower limit value that can be determined.

この診断で、濃度異常と診断した時は、サプライモジュール１７による尿素噴射を禁止し、またＥＣＵを通して、キャビンに設けられた、警告ランプを点灯したり、ブザーで警報音を発したりして運転者に警告し、尿素タンク１６内の尿素水１５を正規のものに入れ替えるように促す。   In this diagnosis, when it is diagnosed that the concentration is abnormal, urea injection by the supply module 17 is prohibited, and a warning lamp provided in the cabin is turned on or an alarm sound is emitted by a buzzer through the ECU. Is urged to replace the urea water 15 in the urea tank 16 with a regular one.

この尿素水の濃度に温度条件を考慮する理由を図３の尿素水の状態図により説明する。   The reason why the temperature condition is taken into consideration for the concentration of the urea water will be described with reference to the urea water phase diagram of FIG.

先ず、使用する尿素水の初期の濃度（所定濃度）は３２．５％である。   First, the initial concentration (predetermined concentration) of urea water to be used is 32.5%.

図３の状態図は、尿素水の尿素濃度と尿素水温度における凍結温度線Ｌｓと飽和温度線Ｌｄを表したものである。   The state diagram of FIG. 3 represents the freezing temperature line Ls and the saturation temperature line Ld at the urea concentration of urea water and the urea water temperature.

通常、尿素水は、その濃度が３２．５％以上では、−１１℃で凍結し、また濃度が薄くなり０％（水）のときは０℃で凍結するため、この濃度における凍結温度を凍結温度線Ｌｓとした。またこの凍結温度線Ｌｓに沿った破線は、凍結温度線Ｌｓに対して±３℃の領域を示している。   Usually, urea water freezes at −11 ° C. when the concentration is 32.5% or more, and freezes at 0 ° C. when the concentration is 0% (water), and the freezing temperature at this concentration is frozen. It was set as the temperature line Ls. The broken line along the freezing temperature line Ls indicates a region of ± 3 ° C. with respect to the freezing temperature line Ls.

飽和温度線Ｌｄは、尿素の溶解度（０℃で４０．０％、１０℃で４５．９％、２０℃で５１．９％、３０℃で５８％）から尿素水濃度と尿素水温度の関係で示した。またこの飽和温度線Ｌｄに沿った破線は、飽和温度線Ｌｄに対して±３℃の領域を示している。   The saturation temperature line Ld indicates the relationship between urea water concentration and urea water temperature based on urea solubility (40.0% at 0 ° C, 45.9% at 10 ° C, 51.9% at 20 ° C, 58% at 30 ° C). It showed in. A broken line along the saturation temperature line Ld indicates a region of ± 3 ° C. with respect to the saturation temperature line Ld.

この図３において、市販されている尿素水の初期濃度３２．５０％を所定の濃度とし、許容できる正常濃度の下限値Ａを、例えば２４％、上限値Ｂを、例えば４８％とし、この範囲（２４〜４８％）以外は異常と判定する場合を説明する。   In FIG. 3, an initial concentration of 32.50% of commercially available urea water is set as a predetermined concentration, and a lower limit value A of an allowable normal concentration is set to, for example, 24%, and an upper limit value B is set to, for example, 48%. A case where it is determined that an abnormality other than (24 to 48%) will be described.

従来判定においては、尿素水の凍結温度−１１℃に対して、尿素水が、測定誤差を含めて確実に凍結していない−５℃を判定可能水温とし、その判定可能水温以上のときに、尿素水の濃度の判定を行っているが、この判定では、判定可能水温−５℃以下の場合、尿素水の濃度が薄い側は、２４％までは異常判定可能であるが、尿素水の濃度が濃い側は、３４％濃度までしか異常判定が行えない不都合がある。   In the conventional determination, when the urea water is not frozen with certainty including a measurement error with respect to the freezing temperature of −11 ° C., −5 ° C. is set as a determinable water temperature, and when the water temperature is equal to or higher than the determinable water temperature, The concentration of the urea water is determined. In this determination, when the water temperature is -5 ° C. or lower, the urea water concentration can be determined to be abnormal up to 24%. On the dark side, there is an inconvenience that an abnormality can be determined only up to 34% density.

そこで、本発明においては、所定濃度（３２．５％）よりも濃度が低いときには、凍結温度線Ｌｓに基づく濃度（３２．５〜０％）における凍結温度（−１１℃〜０℃）に対して、確実に凍結していない＋５℃高い温度（−６℃〜＋５℃）を判定可能下限値βとし、また所定濃度（３２．５％）よりも濃度が高いときには、その飽和温度線Ｌｄに基づく濃度（３２．５〜５８％）における飽和温度（−１１℃〜３０℃）よりも＋５℃高い温度（−６℃〜＋３５℃）を判定可能下限値βとして記憶しておく。   Therefore, in the present invention, when the concentration is lower than the predetermined concentration (32.5%), the freezing temperature (−11 ° C. to 0 ° C.) at the concentration (32.5 to 0%) based on the freezing temperature line Ls. If the temperature is higher than −5 ° C. (−6 ° C. to + 5 ° C.) and is not reliably frozen, and the lower limit value β can be determined, and the concentration is higher than the predetermined concentration (32.5%), the saturation temperature line Ld A temperature (−6 ° C. to + 35 ° C.) that is + 5 ° C. higher than the saturation temperature (−11 ° C. to 30 ° C.) at the concentration based on (32.5 to 58%) is stored as the lower limit determination value β.

尿素水の品質診断の際には、先ず尿素水の濃度と温度を検出し、その検出した濃度に応じて上述の判定可能下限値βを個別に設定しておく。   In the quality diagnosis of urea water, first, the concentration and temperature of the urea water are detected, and the above-described determinable lower limit β is individually set according to the detected concentration.

次に検出した温度と濃度に応じて設定した判定可能下限値βを比較し、検出した温度が判定可能下限値β以上であれば、検出濃度に基づく尿素の品質診断を行い、検出した温度が判定可能下限値βを下回ったときには判定しないようにするものである。   Next, the detected temperature and the lower limit value β that can be determined according to the concentration are compared. If the detected temperature is equal to or higher than the lower limit value β that can be determined, a quality diagnosis of urea is performed based on the detected concentration. When the value falls below the lower limit value β that can be determined, the determination is not made.

すなわち、例えば正常濃度範囲を２４〜４８％としたとき、所定濃度より低い側で、正常濃度下限値Ａ（２４％）での凍結温度−８℃に対しては、確実に凍結しない温度として３℃高い−５℃を凍結温度とし、これを判定可能水温下限値βに、濃度３２．５％のときには−６℃を判定可能水温下限値βに、また濃度０％のときには、＋５℃を判定可能水温下限値βに設定する。   That is, for example, when the normal concentration range is 24 to 48%, on the side lower than the predetermined concentration, the freezing temperature of −8 ° C. at the normal concentration lower limit A (24%) is 3 A freezing temperature of -5 ° C, which is higher, is determined as a water temperature lower limit value β. When the concentration is 32.5%, -6 ° C can be determined. When the concentration is 0%, it is determined as + 5 ° C. Set to possible water temperature lower limit β.

また所定濃度より高い側で、正常濃度上限値Ｂ（４８％）での飽和温度１４℃に対して、確実に析出しない温度として３℃高い１７℃を、判定可能水温下限値βとし、濃度３２．５％のときには−６℃を判定可能水温下限値βに、また濃度５８％のときには、３５℃を判定可能水温下限値βに設定する。   On the side higher than the predetermined concentration, 17 ° C., which is 3 ° C. higher than the saturation temperature of 14 ° C. at the normal concentration upper limit B (48%), which is not reliably deposited, is set as the determinable water temperature lower limit β and the concentration is 32. When it is 5%, −6 ° C. is set as the determinable water temperature lower limit value β, and when the concentration is 58%, 35 ° C. is set as the determinable water temperature lower limit value β.

これにより、所定濃度（３２．５％）に対して濃度が低い側では、検出した尿素温度が、確実に凍結しない判定可能水温下限値β以上であれば、適正な濃度診断が行え、凍結しているおそれのある判定可能水温下限値βを下回ったときには判定を行わないようにすることで、誤診防止できる。   As a result, if the detected urea temperature is equal to or higher than the determinable water temperature lower limit β that does not reliably freeze on the low concentration side with respect to the predetermined concentration (32.5%), an appropriate concentration diagnosis can be performed and Misdiagnosis can be prevented by preventing the determination when the water temperature falls below the lower limit value β that can be determined.

また、所定濃度（３２．５％）に対して濃度が高い側では、検出した尿素温度が、尿素が確実に析出しない判定可能水温下限値β以上であれば、適正な濃度診断が行え、析出しているおそれのある判定可能水温下限値βを下回ったときには判定を行わないようにすることで、誤診防止できる。   On the higher concentration side with respect to the predetermined concentration (32.5%), if the detected urea temperature is equal to or higher than the determinable water temperature lower limit β at which urea does not deposit reliably, an appropriate concentration diagnosis can be performed and precipitation Misdiagnosis can be prevented by preventing the determination when the water temperature is lower than the lower limit value β that can be determined.

次にこの本発明の尿素品質診断システムのフローを図２により説明する。   Next, the flow of the urea quality diagnosis system of the present invention will be described with reference to FIG.

診断をスタートし、ｓｔｅｐ１で、検出尿素水濃度と温度から判定可能水温下限値βを設定し、次にｓｔｅｐ２で、検出した温度が判定可能水温下限値β以上かどうか判断する。このｓｔｅｐ２の判断で、検出した温度が判定可能水温下限値βを下回るときには（ＮＯ）、ｓｔｅｐ３で判定しないとして診断を終了する。   Diagnosis is started, and in step 1, a determinable water temperature lower limit value β is set from the detected urea water concentration and temperature, and in step 2, it is determined whether or not the detected temperature is equal to or greater than the determinable water temperature lower limit value β. If the detected temperature falls below the determinable water temperature lower limit β in the determination of step 2 (NO), the diagnosis is terminated by not determining in step 3.

ｓｔｅｐ２の判断で、検出した温度が、判定可能水温下限値β以上のとき、ｓｔｅｐ４で、尿素水濃度が正常濃度下限値Ａ（濃度２４％）以上かどうかを診断し、正常濃度下限値Ａを下回るとき（ＮＯ）には、ｓｔｅｐ７で異常判定、ｓｔｅｐ８で尿素噴射停止、ｓｔｅｐ８で警告ランプ点灯して診断を終了する。   In step 2, when the detected temperature is equal to or higher than the determinable water temperature lower limit β, it is diagnosed in step 4 whether the urea water concentration is equal to or higher than the normal concentration lower limit A (concentration 24%), and the normal concentration lower limit A is set. When it falls below (NO), the abnormality determination is made at step 7, the urea injection is stopped at step 8, the warning lamp is turned on at step 8, and the diagnosis is finished.

次にｓｔｅｐ４の判断で、尿素水濃度が正常濃度下限値Ａ（濃度２４％）以上のとき（ＹＥＳ）、ｓｔｅｐ５で、尿素濃度が正常濃度上限値Ｂ（濃度４８％）以下かどうかを診断し、正常濃度上限値Ｂを超えるとき（ＮＯ）には、ｓｔｅｐ７で異常判定、ｓｔｅｐ８で尿素噴射停止、ｓｔｅｐ８で警告ランプ点灯して診断を終了する。   Next, in step 4, when the urea water concentration is equal to or higher than the normal concentration lower limit A (concentration 24%) (YES), it is diagnosed in step 5 whether the urea concentration is lower than the normal concentration upper limit B (concentration 48%). When the normal concentration upper limit B is exceeded (NO), the abnormality determination is made at step 7, the urea injection is stopped at step 8, the warning lamp is turned on at step 8, and the diagnosis is finished.

このｓｔｅｐ５判断で、尿素濃度が正常濃度上限値Ｂ（濃度４８％）以下であるとき（ＹＥＳ）には、ｓｔｅｐ６で正常判定を行って診断を終了する。   If it is determined in step 5 that the urea concentration is equal to or lower than the normal concentration upper limit B (concentration 48%) (YES), normal determination is performed in step 6 and the diagnosis is terminated.

このように、先ず検出した尿素濃度で、その濃度応じた判定可能水温下限値βを個別に設定することで、尿素凍結と尿素の飽和析出条件下での判定は行わずに、尿素濃度による診断を行うことで確実な診断が行える。   In this way, by first setting the detectable water temperature lower limit β according to the detected urea concentration individually, diagnosis based on the urea concentration is performed without performing determination under urea freezing and urea saturation precipitation conditions. A reliable diagnosis can be made by performing.

図２の制御フローは、尿素の濃度に応じて、判定可能水温下限値βを個別に設定して、検出温度と比較して診断を行う制御を説明したが、異常判定は、尿素水濃度が正常濃度下限値Ａ（濃度２４％）を下回るときと、正常濃度上限値Ｂ（濃度４８％）を超えるときの異常診断が制御的には重要である。そこで、簡易的制御としての制御フローを説明する。   The control flow of FIG. 2 has explained the control in which the determination possible water temperature lower limit β is individually set according to the urea concentration and the diagnosis is performed by comparison with the detected temperature. Abnormal diagnosis when the normal concentration lower limit A (concentration 24%) is below and when the normal concentration upper limit B (concentration 48%) is exceeded is important in terms of control. Therefore, a control flow as simple control will be described.

この制御フローは、検出尿素濃度が、正常濃度下限値Ａ（濃度２４％）を超え、正常濃度上限値Ｂを下回るときには、尿素濃度が正常と判定し、正常濃度下限値Ａ以下又は正常濃度上限値Ｂ以上のときには、正常濃度下限値Ａと正常濃度上限値Ｂの濃度における判定可能水温下限値βＬ、βＨを設定しておき、正常範囲のときには、正常と判断しておき、判定可能水温下限値βＬ、βＨ以上のときには異常と判定し、判定可能水温下限値βＬ、βＨを下回るときには品質判定を行わないようにすることで、品質診断を簡便に行えるようにしたものである。   In this control flow, when the detected urea concentration exceeds the normal concentration lower limit value A (concentration 24%) and falls below the normal concentration upper limit value B, it is determined that the urea concentration is normal, and the normal concentration lower limit value A or lower or the normal concentration upper limit value. When the value is equal to or greater than B, the water temperature lower limit values βL and βH that can be determined at the normal concentration lower limit value A and the normal concentration upper limit value B are set. When the values βL and βH are greater than or equal to the values βL and βH, it is determined that there is an abnormality, and when the values are lower than the determinable water temperature lower limit values βL and βH, the quality determination is not performed, so

この簡易制御のフローを図４により説明する。   The flow of this simple control will be described with reference to FIG.

診断をスタートし、ｓｔｅｐ１で、検出した尿素水濃度が正常濃度下限値（例えば２４％）Ａ以下かどうかを判断する。このｓｔｅｐ１で、尿素水濃度が正常濃度下限値Ａ以上のとき（ＹＥＳ）には、次のｓｔｅｐ２で、尿素水濃度が正常濃度上限値（例えば４８％）Ｂ以上かどうかを判断し、正常濃度上限値Ｂ以下であるときは、ｓｔｅｐ５で正常判定を行って、診断を終了（リターン）とする。   The diagnosis is started, and at step 1, it is determined whether or not the detected urea water concentration is equal to or lower than the normal concentration lower limit (for example, 24%) A. If the urea water concentration is equal to or higher than the normal concentration lower limit value A in step 1 (YES), it is determined in the next step 2 whether the urea water concentration is equal to or higher than the normal concentration upper limit value (for example, 48%) B. When it is less than or equal to the upper limit value B, normal determination is made at step 5, and the diagnosis is completed (return).

またｓｔｅｐ１の判断で尿素水の濃度が、正常濃度下限値Ａを下回るとき（ＮＯ）、次のｓｔｅｐ４の判断で、検出した尿素水温度が、βＬ≦尿素水温を判断し、βＬ（例えば−５℃）以上のとき（ＹＥＳ）には、ｓｔｅｐ６で異常判定を行い、ｓｔｅｐ６で尿素噴射禁止，ｓｔｅｐ７で警告ランプ点灯を行って診断を終了とする。またｓｔｅｐ４の判断で、βＬ未満（ＮＯ）では、ｓｔｅｐ９で判定しないとして診断を終了とする。   When the concentration of urea water is lower than the normal concentration lower limit A in step 1 (NO), the detected urea water temperature is determined as βL ≦ urea water temperature in the next step 4, and βL (for example, −5) When the temperature is equal to or higher than (° C.), the abnormality is determined at step 6, urea injection is prohibited at step 6, and the warning lamp is turned on at step 7 to complete the diagnosis. If the determination at step 4 is less than βL (NO), the determination is terminated at step 9 without determination at step 9.

次にｓｔｅｐ２の判断で、尿素水濃度が正常濃度上限値Ｂを超えるとき（ＮＯ）は、ｓｔｅｐ３の判断で、検出した尿素水温度が、βＨ≦尿素水温を判断し、βＨ（例えば１７℃）以上のとき（ＹＥＳ）には、ｓｔｅｐ６で異常判定を行い、ｓｔｅｐ７で尿素噴射禁止４４，ｓｔｅｐ８で警告ランプ点灯を行って診断を終了とする。さらに、ｓｔｅｐ３の判断で、検出した尿素水温度が、βＨを下回るときにはｓｔｅｐ１０で判定しないとして診断を終了する。   Next, when the urea water concentration exceeds the normal concentration upper limit B in the determination of step 2 (NO), the detected urea water temperature is determined to be βH ≦ urea water temperature in the determination of step 3, and βH (for example, 17 ° C.) At this time (YES), abnormality determination is performed at step 6, urea injection prohibition 44 is performed at step 7, and a warning lamp is lit at step 8, and the diagnosis is terminated. Further, when the detected urea water temperature is lower than βH in the determination of step 3, the diagnosis is terminated as it is not determined in step 10.

この図４のフローにおいては、尿素水濃度が２４〜４８％の範囲は無条件で正常と判断し、濃度が正常範囲外にあるときのみ、検出温度と判定可能水温下限値βＬ、βＨを比較して異常判定をするか、判定せずにおくかを判断することで、簡便な異常判断が行える。   In the flow of FIG. 4, the urea water concentration range of 24 to 48% is judged to be normal unconditionally, and the detected temperature and the determinable water temperature lower limit values βL and βH are compared only when the concentration is outside the normal range. Thus, it is possible to make a simple abnormality determination by determining whether the abnormality is determined or not.

１０ 排気管
１１ ＳＣＲ装置
１２ 噴射ノズル
１５ 尿素水
１６ 尿素タンク
２０ ＤＣＵ
２３ 尿素センサ DESCRIPTION OF SYMBOLS 10 Exhaust pipe 11 SCR apparatus 12 Injection nozzle 15 Urea water 16 Urea tank 20 DCU
23 Urea sensor

Claims (4)

尿素タンク内の尿素水の濃度と温度を検出して、その尿素水の品質を診断する尿素品質診断システムにおいて、尿素水の濃度に応じて判定可能水温下限値を個別に設定し、検出した尿素水温度が、個別に設定された判定可能水温下限値より高いとき濃度の品質判定を行い、前記個別に設定された判定可能水温下限値を下回ったとき濃度の品質判定を行わないようにしたことを特徴とする尿素品質診断システム。   In the urea quality diagnosis system that detects the concentration and temperature of urea water in the urea tank and diagnoses the quality of the urea water, the water temperature lower limit value that can be determined according to the concentration of urea water is individually set and detected urea Concentration quality judgment is performed when the water temperature is higher than the individually set lower limit value of the water temperature that can be determined, and the concentration quality is not determined when the water temperature is lower than the individually set lower limit value of the water temperature that can be determined. Urea quality diagnostic system characterized by 検出した尿素水の濃度が所定濃度より高いときの判定可能水温下限値を、尿素水の正常濃度上限値で尿素析出が起きない飽和温度以上に設定している請求項１記載の尿素品質診断システム。   The urea quality diagnosis system according to claim 1, wherein the lower limit value of water temperature that can be determined when the detected concentration of urea water is higher than a predetermined concentration is set to a saturation temperature or higher at which urea precipitation does not occur at the normal concentration upper limit value of urea water. . 検出した尿素水の濃度が所定濃度よりも低いときの判定可能水温下限値を、尿素が凍結しない凍結温度以上に設定する請求項１記載の尿素品質診断システム。   The urea quality diagnosis system according to claim 1, wherein the lower limit value of water temperature that can be determined when the detected concentration of urea water is lower than a predetermined concentration is set to be equal to or higher than a freezing temperature at which urea does not freeze. 濃度異常と診断したとき、尿素噴射を禁止し、これを運転者に警告するようにした請求項１〜３いずれかに記載の尿素品質診断システム。   The urea quality diagnosis system according to any one of claims 1 to 3, wherein when a concentration abnormality is diagnosed, urea injection is prohibited and a warning is given to the driver.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014226501A (en) * 2013-05-27 2014-12-08 株式会社Ｌｉｘｉｌ Bathtub
WO2014199777A1 (en) 2013-06-10 2014-12-18 ボッシュ株式会社 Control device, exhaust purification device for internal combustion engine, and method for controlling exhaust purification device
WO2014203802A1 (en) * 2013-06-17 2014-12-24 日野自動車 株式会社 Urea water suitability determination device
KR101725108B1 (en) * 2015-12-02 2017-04-10 전남대학교산학협력단 A measuring device of level and concentration of urea-water solution tank of a urea-SCR system for automotive diesel vehicles using ultrasonic
WO2018110489A1 (en) * 2016-12-15 2018-06-21 株式会社堀場製作所 Method for evaluating alkalinity of urea water
CN114648861A (en) * 2022-03-17 2022-06-21 潍柴动力股份有限公司 Urea tank cleaning early warning method, device, system and medium

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005147118A (en) * 2003-10-22 2005-06-09 Nissan Diesel Motor Co Ltd Exhaust emission control device of engine
JP2008095601A (en) * 2006-10-12 2008-04-24 Nissan Diesel Motor Co Ltd Exhaust emission controller of engine
WO2009008408A1 (en) * 2007-07-06 2009-01-15 Mitsui Mining & Smelting Co., Ltd. Liquid freezing point identifying device, freezing preventing apparatus for liquid storage tank utilizing the same, and automobile exhaust gas reducing apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005147118A (en) * 2003-10-22 2005-06-09 Nissan Diesel Motor Co Ltd Exhaust emission control device of engine
JP2008095601A (en) * 2006-10-12 2008-04-24 Nissan Diesel Motor Co Ltd Exhaust emission controller of engine
WO2009008408A1 (en) * 2007-07-06 2009-01-15 Mitsui Mining & Smelting Co., Ltd. Liquid freezing point identifying device, freezing preventing apparatus for liquid storage tank utilizing the same, and automobile exhaust gas reducing apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014226501A (en) * 2013-05-27 2014-12-08 株式会社Ｌｉｘｉｌ Bathtub
WO2014199777A1 (en) 2013-06-10 2014-12-18 ボッシュ株式会社 Control device, exhaust purification device for internal combustion engine, and method for controlling exhaust purification device
US10052588B2 (en) 2013-06-10 2018-08-21 Bosch Corporation Control apparatus, exhaust purifying apparatus for internal combustion engine, and control method for exhaust purifying apparatus
WO2014203802A1 (en) * 2013-06-17 2014-12-24 日野自動車 株式会社 Urea water suitability determination device
JP2015001208A (en) * 2013-06-17 2015-01-05 日野自動車株式会社 Propriety determining device for urea water
US9810677B2 (en) 2013-06-17 2017-11-07 Hino Motors, Ltd. Urea water suitability determination device
KR101725108B1 (en) * 2015-12-02 2017-04-10 전남대학교산학협력단 A measuring device of level and concentration of urea-water solution tank of a urea-SCR system for automotive diesel vehicles using ultrasonic
WO2018110489A1 (en) * 2016-12-15 2018-06-21 株式会社堀場製作所 Method for evaluating alkalinity of urea water
CN114648861A (en) * 2022-03-17 2022-06-21 潍柴动力股份有限公司 Urea tank cleaning early warning method, device, system and medium

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