JP2007263034A - Engine cooling water circuit - Google Patents

Engine cooling water circuit Download PDF

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JP2007263034A
JP2007263034A JP2006090840A JP2006090840A JP2007263034A JP 2007263034 A JP2007263034 A JP 2007263034A JP 2006090840 A JP2006090840 A JP 2006090840A JP 2006090840 A JP2006090840 A JP 2006090840A JP 2007263034 A JP2007263034 A JP 2007263034A
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water
cooling water
channel
cooling
outlet
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JP4802811B2 (en
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Yoshio Sekiyama
惠夫 関山
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Isuzu Motors Ltd
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Isuzu Motors Ltd
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    • 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

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cooling water circuit capable of shortening warming-up time, and capable of sufficiently cooling an EGR cooler after finishing warming-up. <P>SOLUTION: This engine cooling water circuit has a first water passage 32 connecting a first cooling water pipe 14 to an EGR cooler inlet 43, a second water passage 33 connecting an EGR cooler outlet 44 to a third cooling water pipe 20, a third water passage 34 connecting the third cooling water pipe 20 on the upstream side of the second water passage 33 to the first water passage 32, a fourth water passage 36 connecting the second water passage 33 to a second cooling water pipe 17 on the downstream side of a thermostat 10, a first solenoid valve 26 opening and closing the first water passage 32 on the upstream side of the third water passage 34, a fourth solenoid valve 29 opening and closing the second water passage 33 on the downstream side of the fourth water passage 36, a pump 35 sending cooling water to the first water passage 32 side from the third cooling water pipe 20 side, a second solenoid valve 27 opening and closing the third water passage 34 on the downstream side of the pump 35, a third solenoid valve 28 opening and closing the fourth water passage 36, a water temperature detecting means 30 detecting the engine outlet water temperature, and a control means 31 controlling the pump 35 for ON/OFF and controlling opening-closing of the solenoid valves on the basis of this detecting temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、エンジンウォータジャケット、ラジエータ間で冷却水を循環させると共に、この冷却水をＥＧＲ（Exhaust Gas Recirculation）クーラに循環させるエンジンの冷却水回路に関する。   The present invention relates to an engine cooling water circuit that circulates cooling water between an engine water jacket and a radiator and circulates the cooling water to an EGR (Exhaust Gas Recirculation) cooler.

車両用のディーゼル又はガソリンエンジンの冷却水回路としては、図５、図６及び図７に示すものが知られている。図５に示す冷却水回路５０は、エンジンウォータジャケット６、ラジエータ７間で冷却水を循環させる循環水路８に、暖機時にラジエータ７を迂回させるバイパス水路９及びエンジン用サーモスタット１０を設けたものであり、エンジン出口１５から冷却水の一部を取水してＥＧＲクーラ４に導入すると共に冷却水をラジエータ入口１６に戻すように構成されている。   As a cooling water circuit of a diesel or gasoline engine for a vehicle, those shown in FIGS. 5, 6 and 7 are known. A cooling water circuit 50 shown in FIG. 5 is provided with a bypass water channel 9 and a thermostat 10 for the engine that bypass the radiator 7 during warm-up in a circulating water channel 8 that circulates cooling water between the engine water jacket 6 and the radiator 7. Yes, a part of the cooling water is taken from the engine outlet 15 and introduced into the EGR cooler 4, and the cooling water is returned to the radiator inlet 16.

図６に示す冷却水回路５１は、上記ＥＧＲクーラ４に取水する水路に変更が加えられたものであり、エンジン入口１３から冷却水の一部を取水するようになっている。   The cooling water circuit 51 shown in FIG. 6 is a modification of the water channel for taking water into the EGR cooler 4, and takes a part of the cooling water from the engine inlet 13.

図７に示す冷却水回路５２は、上記ＥＧＲクーラ４に取水する水路に更に変更が加えられたものであり、ラジエータ出口１８から冷却水の一部を取水するようになっている。この場合、循環水路８の下流側から上流側に冷却水を流すこととなるため、ＥＧＲクーラ４に冷却水を取り込む入口水路５３にＥＧＲクーラ用水ポンプ３５を設けている。   The cooling water circuit 52 shown in FIG. 7 is obtained by further changing the water path for taking water into the EGR cooler 4, and takes a part of the cooling water from the radiator outlet 18. In this case, since the cooling water flows from the downstream side to the upstream side of the circulation water channel 8, the EGR cooler water pump 35 is provided in the inlet water channel 53 that takes the cooling water into the EGR cooler 4.

特開２００４−２９３３６９号公報JP 2004-293369 A

ところで、エンジン始動後、冷却水温度が所定温度を超えるまでエンジン２の排気ガス中にＨＣ（hydrocarbon）成分が多く排出されることは周知であり、今後強化される排気ガス規制に対応するには、暖機中のＨＣ低減、暖機終了後のＮＯｘ低減が大きな課題となるが、図５記載の冷却水回路５０は、エンジン出口１５から冷却水の一部を取水してＥＧＲガスを冷却するようになっており、暖機終了時点でのエンジン出口水温が８０℃以上にもなることからＥＧＲガスは冷却水温度以下には下がらず、ＥＧＲガスを充分冷却することができず、給気中のＣＯ2濃度を充分高めることができないため、ＮＯｘを充分低減できないという課題があった。また、暖機中におけるエンジン水温の上昇はエンジン２からの放熱量のみによって決まり、冷却水がＥＧＲガスから受けた放熱はラジエータ７からの放熱によって大気に拡散され、エンジン２の暖機には寄与しない。このため、暖機時間を短縮してＨＣ排出量を低減することはできなかった。そして、暖機中はＥＧＲガスが過冷却され、ＥＧＲガス中の水分の結露等によってＥＧＲクーラ４内部が汚損されやすいという課題があった。 By the way, after the engine is started, it is well known that a lot of HC (hydrocarbon) components are discharged in the exhaust gas of the engine 2 until the cooling water temperature exceeds a predetermined temperature. HC reduction during warm-up and NOx reduction after completion of warm-up are major issues, but the cooling water circuit 50 shown in FIG. 5 cools the EGR gas by taking a part of the cooling water from the engine outlet 15. Since the engine outlet water temperature at the end of warm-up becomes 80 ° C. or higher, the EGR gas does not fall below the cooling water temperature, and the EGR gas cannot be sufficiently cooled, and the air is being supplied. However, since the CO 2 concentration cannot be sufficiently increased, NOx cannot be sufficiently reduced. In addition, the rise in engine water temperature during warm-up is determined only by the amount of heat released from the engine 2, and the heat released from the EGR gas by the cooling water is diffused into the atmosphere by the heat released from the radiator 7, contributing to the warm-up of the engine 2. do not do. For this reason, it was not possible to reduce the HC emission amount by shortening the warm-up time. During the warm-up, the EGR gas is supercooled, and there is a problem that the inside of the EGR cooler 4 is easily contaminated due to condensation of moisture in the EGR gas.

また、図６記載の冷却水回路５１は、エンジン入口１３から取水してＥＧＲガスを冷却するものであり、暖機終了後、エンジン入口１３の水温は出口温度に対して１０℃前後低くなるため、ＥＧＲクーラ４の放熱量が増し、ＥＧＲガスの冷却には図５記載の冷却水回路５０より効果的である。しかしながら、暖機中にＥＧＲガスからの熱を大気放熱する点は上述と同様であり、ＨＣ排出量の低減はできず、ＥＧＲクーラ４内部が汚損されやすいという課題があった。   Further, the cooling water circuit 51 shown in FIG. 6 takes in water from the engine inlet 13 and cools the EGR gas. After the warm-up is completed, the water temperature at the engine inlet 13 is about 10 ° C. lower than the outlet temperature. The amount of heat released from the EGR cooler 4 is increased, and cooling of the EGR gas is more effective than the cooling water circuit 50 shown in FIG. However, the point that the heat from the EGR gas is dissipated to the atmosphere during warm-up is the same as described above, and there is a problem that the amount of HC emission cannot be reduced, and the inside of the EGR cooler 4 is easily contaminated.

図７記載の冷却水回路５２は、ラジエータ出口１８から取水してＥＧＲガスを冷却するものであるため、ＥＧＲクーラ４に導入される冷却水の温度は図５〜図７に示す３例中で最も低く、ＥＧＲガスの冷却効果が最大となる。しかしながら、ラジエータ出口１８の冷却水温は、エンジン２が充分に暖機され、サーモスタット１０が開いて高温になったエンジン冷却水の一部、又は全部がラジエータ７に入るまで、ＥＧＲガスは過冷却になる時間帯が延び、ＨＣ排出量の低減ができないと共にＥＧＲガス中の水分の結露等によってＥＧＲクーラ４内部が汚損されやすいという課題があった。   Since the cooling water circuit 52 shown in FIG. 7 takes water from the radiator outlet 18 and cools the EGR gas, the temperature of the cooling water introduced into the EGR cooler 4 is in three examples shown in FIGS. The lowest, the cooling effect of EGR gas is maximized. However, the cooling water temperature at the radiator outlet 18 is such that the EGR gas is subcooled until the engine 2 is sufficiently warmed up and the thermostat 10 is opened and a part or all of the high temperature engine cooling water enters the radiator 7. There is a problem in that the time period during which the EGR cooler 4 cannot be reduced and the inside of the EGR cooler 4 is easily contaminated due to condensation of moisture in the EGR gas.

なお、特許文献１記載のエンジンの冷却水回路は、ＥＧＲクーラでＥＧＲガスを冷却し、これにより温度が上がったＥＧＲクーラの冷却水を車両ヒータに導入し、ヒータの効きを高めるものである。すなわち、暖機中に積極的に冷却水の熱を大気放出するものである。   The engine cooling water circuit described in Patent Document 1 cools EGR gas with an EGR cooler, and introduces cooling water of the EGR cooler whose temperature has risen to the vehicle heater, thereby enhancing the effectiveness of the heater. That is, the heat of the cooling water is positively released to the atmosphere during warm-up.

そこで、本発明の目的は、上記課題を解決し、暖機時間を短縮でき、かつ、暖機終了後にＥＧＲクーラを充分冷却することができるエンジンの冷却水回路を提供することにある。   Therefore, an object of the present invention is to provide an engine coolant circuit that can solve the above-described problems, shorten the warm-up time, and sufficiently cool the EGR cooler after the warm-up is completed.

上記課題を解決するために本発明は、エンジン用水ポンプの吐出口とエンジンウォータジャケットの入口を接続する第１冷却水管と、前記エンジンウォータジャケットの出口とラジエータの入口を接続する第２冷却水管と、前記ラジエータの出口と前記エンジン用水ポンプの吸込口を接続する第３冷却水管と、前記第２冷却水管と前記第３冷却水管を接続するバイパス水管と、冷却水の水温が所定温度に満たないとき前記バイパス水管に冷却水を流通させると共にラジエータへの冷却水の流通を止め、前記水温が所定温度以上のとき前記バイパス水管への冷却水の流通を止めると共にラジエータに冷却水を流通させるサーモスタットと、前記いずれかの冷却水管から冷却水を取り込んでＥＧＲガスとの熱交換を行うＥＧＲクーラとを備えたエンジンの冷却水回路において、前記第１冷却水管とＥＧＲクーラの入口を接続する第１水路と、前記ＥＧＲクーラの出口と第３冷却水管を接続する第２水路と、該第２水路より上流側の第３冷却水管と前記第１水路とを接続する第３水路と、前記第２水路と前記サーモスタットの下流側の第２冷却水管を接続する第４水路と、前記第３水路より上流側の第１水路を開閉する第１電磁バルブと、第４水路の下流側の第２水路を開閉する第４電磁バルブと、第３水路に設けられ第３冷却水管側から第１水路側に冷却水を送るＥＧＲクーラ用水ポンプと、該ＥＧＲクーラ用水ポンプの下流側の第３水路を開閉する第２電磁バルブと、前記第４水路を開閉する第３電磁バルブと、エンジン出口水温を検出する水温検出手段と、該水温検出手段の検出温度に基づいて前記ＥＧＲクーラ用水ポンプをオンオフ制御すると共に前記各電磁バルブを開閉制御する制御手段とを備えるものである。   In order to solve the above-described problems, the present invention provides a first cooling water pipe that connects an outlet of an engine water pump and an inlet of an engine water jacket, and a second cooling water pipe that connects an outlet of the engine water jacket and an inlet of a radiator. The third cooling water pipe connecting the outlet of the radiator and the suction port of the engine water pump, the bypass water pipe connecting the second cooling water pipe and the third cooling water pipe, and the cooling water temperature does not reach a predetermined temperature. When the cooling water is circulated through the bypass water pipe and the circulation of the cooling water to the radiator is stopped, and when the water temperature is equal to or higher than a predetermined temperature, the circulation of the cooling water to the bypass water pipe is stopped and the cooling water is circulated through the radiator; An EGR cooler that takes in the cooling water from any one of the cooling water pipes and performs heat exchange with the EGR gas. In the cooling water circuit of the gin, the first water channel connecting the first cooling water pipe and the inlet of the EGR cooler, the second water channel connecting the outlet of the EGR cooler and the third cooling water pipe, and the upstream side of the second water channel A third water channel connecting the third cooling water pipe and the first water channel, a fourth water channel connecting the second water channel and the second cooling water pipe downstream of the thermostat, and an upstream side of the third water channel. A first electromagnetic valve for opening and closing the first water channel, a fourth electromagnetic valve for opening and closing a second water channel downstream of the fourth water channel, and cooling water provided in the third water channel from the third cooling water pipe side to the first water channel side An EGR cooler water pump, a second electromagnetic valve for opening and closing a third water passage downstream of the EGR cooler water pump, a third electromagnetic valve for opening and closing the fourth water passage, and a water temperature detection for detecting an engine outlet water temperature And temperature detected by the water temperature detecting means In which a control means for controlling opening and closing each of said solenoid valves with on-off controlling the EGR cooler water pump based on.

前記制御手段は、前記水温検出手段で検出された出口水温が所定温度以下のとき、前記エンジン用水ポンプの吐出側からＥＧＲクーラに冷却水を導くと共に、ＥＧＲクーラにて暖められた冷却水をエンジン用水ポンプの吸込側に戻す回路を形成すべく、前記ＥＧＲクーラ用水ポンプを停止し、前記第１電磁バルブと第４電磁バルブを開弁すると共に、前記第２電磁バルブと第３電磁バルブを閉弁するとよい。   The control means guides the cooling water from the discharge side of the engine water pump to the EGR cooler when the outlet water temperature detected by the water temperature detecting means is equal to or lower than a predetermined temperature, and supplies the cooling water warmed by the EGR cooler to the engine. In order to form a circuit for returning to the suction side of the water pump, the EGR cooler water pump is stopped, the first electromagnetic valve and the fourth electromagnetic valve are opened, and the second electromagnetic valve and the third electromagnetic valve are closed. It is good to speak.

前記制御手段は、前記水温検出手段で検出された出口水温が所定温度を超えるとき、前記ラジエータの出口側からＥＧＲクーラに冷却水を導くと共に、ＥＧＲクーラにて暖められた冷却水をラジエータの入口側に戻す回路を形成すべく、前記ＥＧＲクーラ用水ポンプを駆動し、前記第２電磁バルブと第３電磁バルブを開弁すると共に、前記第１電磁バルブと第４電磁バルブを閉弁するとよい。   When the outlet water temperature detected by the water temperature detection means exceeds a predetermined temperature, the control means guides the cooling water from the outlet side of the radiator to the EGR cooler, and supplies the cooling water warmed by the EGR cooler to the inlet of the radiator In order to form a circuit to return to the side, the EGR cooler water pump is driven to open the second electromagnetic valve and the third electromagnetic valve, and close the first electromagnetic valve and the fourth electromagnetic valve.

また、エンジンウォータジャケット、ラジエータ間で冷却水を循環させる循環水路と、前記ラジエータの上流側の循環水路と下流側の循環水路を接続するバイパス水路と、冷却水の水温が所定温度に満たないときバイパス水路に冷却水を流通させると共にラジエータへの冷却水の流通を止め、前記水温が所定温度以上のとき前記バイパス水路への冷却水の流通を止めると共にラジエータに冷却水を流通させるサーモスタットと、前記循環水路に前記バイパス水路よりもエンジン側に位置して設けられ冷却水を循環させるエンジン用水ポンプと、前記循環水路から冷却水を取り込んでＥＧＲガスとの熱交換を行うＥＧＲクーラとを備えたエンジンの冷却水回路において、前記ラジエータの出口側の循環水路から前記ＥＧＲクーラに冷却水を取り込むための入口水路と、前記ＥＧＲクーラからの冷却水を前記ラジエータの入口側の循環水路に戻すための冷却用出口水路と、前記ＥＧＲクーラからの冷却水を前記ラジエータの出口側の循環水路に戻すための暖機用出口水路と、前記ＥＧＲクーラの出口水路を前記冷却用出口水路又は前記暖機用出口水路のいずれか一方に切り替える水路切替手段と、前記循環水路に設けられエンジンの出口水温を検出する水温検出手段と、該水温検出手段で検出された出口水温が所定温度を超えるとき前記冷却用出口水路を開き前記暖機用出口水路を閉じるように前記水路切替手段を作動させ、前記出口水温が所定温度以下のとき前記暖機用出口水路を開き前記冷却用出口水路を閉じるように前記水路切替手段を作動させる制御手段とを備えるとよい。   Also, when the coolant temperature of the cooling water does not reach a predetermined temperature, a circulating water channel for circulating the cooling water between the engine water jacket and the radiator, a bypass water channel connecting the upstream circulating water channel and the downstream circulating water channel, and the cooling water temperature A thermostat that circulates the cooling water to the bypass channel and stops the circulation of the cooling water to the radiator, stops the circulation of the cooling water to the bypass channel when the water temperature is equal to or higher than a predetermined temperature, and circulates the cooling water to the radiator; and An engine including an engine water pump that is provided in the circulation water channel on the engine side of the bypass water channel and circulates the cooling water, and an EGR cooler that takes in the cooling water from the circulation water channel and performs heat exchange with the EGR gas. In this cooling water circuit, cooling water is taken into the EGR cooler from the circulation water channel on the outlet side of the radiator. An inlet water channel for cooling, a cooling outlet water channel for returning the cooling water from the EGR cooler to the circulating water channel on the inlet side of the radiator, and a cooling water channel for returning the cooling water from the EGR cooler to the circulating water channel on the outlet side of the radiator An outlet water channel for warming up, a water channel switching means for switching the outlet water channel of the EGR cooler to either the cooling water channel for cooling or the outlet water channel for warming up, and detecting the outlet water temperature of the engine provided in the circulating water channel Water temperature detecting means, and when the outlet water temperature detected by the water temperature detecting means exceeds a predetermined temperature, operates the water channel switching means to open the cooling outlet water channel and close the warm-up outlet water channel, And control means for operating the water channel switching means to open the warm-up outlet water channel and close the cooling outlet water channel when the temperature is equal to or lower than a predetermined temperature.

本発明によれば、暖機時間を短縮でき、かつ、暖機終了後にＥＧＲクーラを充分冷却することができる。   According to the present invention, the warm-up time can be shortened, and the EGR cooler can be sufficiently cooled after the warm-up is completed.

本発明の好適実施の形態を添付図面を用いて説明する。   Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

図１に示すように、エンジンの冷却水回路１は、エンジン２を冷却するための主回路３と、ＥＧＲクーラ４を冷却すべく主回路３に接続される副回路５とからなる。   As shown in FIG. 1, the engine coolant circuit 1 includes a main circuit 3 for cooling the engine 2 and a sub circuit 5 connected to the main circuit 3 for cooling the EGR cooler 4.

主回路３は、エンジンウォータジャケット（以下、エンジンと略す）６、ラジエータ７間で冷却水を循環させる循環水路８と、ラジエータ７の上流側の循環水路８と下流側の循環水路８を接続するバイパス水路９と、冷却水の水温が所定の設定温度（例えば８０℃）に満たないときバイパス水路９に冷却水を流通させると共にラジエータ７への冷却水の流通を止め、水温が所定温度以上のときバイパス水路９への冷却水の流通を止めると共にラジエータ７に冷却水を流通させるサーモスタット１０と、循環水路８にバイパス水路９よりもエンジン６側に位置して設けられ冷却水を循環させるエンジン用水ポンプ１１とを備えて構成されている。循環水路８は、エンジン用水ポンプ１１の吐出口１２とエンジン６の入口１３を接続する第１冷却水管１４と、エンジン６の出口１５とラジエータ７の入口１６を接続する第２冷却水管１７と、ラジエータ７の出口１８とエンジン用水ポンプ１１の吸込口１９を接続する第３冷却水管２０とを備える。バイパス水路９は、ラジエータ７を迂回するための水路であり、第２冷却水管１７と第３冷却水管２０を接続するバイパス水管２１からなる。サーモスタット１０は第２冷却水管１７とバイパス水管２１との接続部に設けられており、サーモスタット１０内を流れる冷却水の水温に基づいてエンジン６側から流れる冷却水をラジエータ７側の第２冷却水管１７又はバイパス水管２１のいずれか一方に切り替えて流すようになっている。   The main circuit 3 connects an engine water jacket (hereinafter abbreviated as an engine) 6, a circulation water channel 8 for circulating cooling water between the radiator 7, and a circulation water channel 8 upstream of the radiator 7 and a circulation water channel 8 downstream. When the water temperature of the bypass water passage 9 and the cooling water is less than a predetermined set temperature (for example, 80 ° C.), the cooling water is circulated through the bypass water passage 9 and the circulation of the cooling water to the radiator 7 is stopped. When the thermostat 10 stops circulation of the cooling water to the bypass water channel 9 and distributes the cooling water to the radiator 7, the engine water is provided in the circulation water channel 8 on the engine 6 side of the bypass water channel 9 and circulates the cooling water. A pump 11 is provided. The circulation water channel 8 includes a first cooling water pipe 14 that connects the discharge port 12 of the engine water pump 11 and the inlet 13 of the engine 6, a second cooling water pipe 17 that connects the outlet 15 of the engine 6 and the inlet 16 of the radiator 7, A third cooling water pipe 20 connecting the outlet 18 of the radiator 7 and the suction port 19 of the engine water pump 11 is provided. The bypass water passage 9 is a water passage for bypassing the radiator 7, and includes a bypass water pipe 21 that connects the second cooling water pipe 17 and the third cooling water pipe 20. The thermostat 10 is provided at a connection portion between the second cooling water pipe 17 and the bypass water pipe 21, and the cooling water flowing from the engine 6 side based on the temperature of the cooling water flowing through the thermostat 10 is supplied to the second cooling water pipe on the radiator 7 side. 17 or the bypass water pipe 21 is switched to flow.

副回路５は、ＥＧＲガスを冷却するためのＥＧＲクーラ４と、ラジエータ出口１８近傍の循環水路８からＥＧＲクーラ４に冷却水を取り込む冷却用入口水路２２と、エンジン６入口近傍の循環水路８からＥＧＲクーラ４に冷却水を取り込む暖機用入口水路２３と、ＥＧＲクーラ４から排出される冷却水をラジエータ７の入口１６側の循環水路８に戻すための冷却用出口水路２４と、ＥＧＲクーラ４から排出される冷却水をラジエータ７の出口１８側の循環水路８に戻すための暖機用出口水路２５と、ＥＧＲクーラ４の入口水路を冷却用入口水路２２又は暖機用入口水路２３のいずれか一方に切り替える入口側水路切替手段２６、２７と、ＥＧＲクーラ４の出口水路を冷却用出口水路２４又は暖機用出口水路２５のいずれか一方に切り替える出口側水路切替手段２８、２９と、循環水路８に設けられエンジン６の出口水温を検出する水温検出手段３０と、水温検出手段３０で検出された出口水温に基づいて入口側水路切替手段２６、２７と出口側水路切替手段２８、２９を作動させ入口水路２２、２３及び出口水路２４、２５をそれぞれ切り替える制御手段３１とを備えて構成されている。   The auxiliary circuit 5 includes an EGR cooler 4 for cooling the EGR gas, a cooling inlet water passage 22 for taking cooling water into the EGR cooler 4 from the circulation water passage 8 in the vicinity of the radiator outlet 18, and the circulation water passage 8 in the vicinity of the engine 6 inlet. A warm-up inlet water passage 23 for taking in the cooling water to the EGR cooler 4, a cooling outlet water passage 24 for returning the cooling water discharged from the EGR cooler 4 to the circulation water passage 8 on the inlet 16 side of the radiator 7, and the EGR cooler 4 The warming-up outlet water channel 25 for returning the cooling water discharged from the radiator 7 to the circulating water channel 8 on the outlet 18 side of the radiator 7, the cooling water inlet water channel 22 or the warming-up inlet water channel 23 as the inlet water channel of the EGR cooler 4. The inlet-side water channel switching means 26, 27 for switching to one of these and the outlet water channel for the EGR cooler 4 are switched to either the cooling water channel 24 or the warm-up water channel 25. Side water channel switching means 28, 29, water temperature detection means 30 provided in the circulation water channel 8 for detecting the outlet water temperature of the engine 6, and inlet side water channel switching means 26, 27 based on the outlet water temperature detected by the water temperature detection means 30. And control means 31 for operating the outlet side water passage switching means 28 and 29 and switching the inlet water passages 22 and 23 and the outlet water passages 24 and 25, respectively.

ＥＧＲクーラ４は、循環水路８から取り込んだ冷却水とＥＧＲガスとの熱交換によりＥＧＲガスを冷却するものである。冷却すべきＥＧＲガスは、エンジン２の排気側からＥＧＲクーラ４に流入されて冷却水と熱交換したのち、エンジン２の吸気側へ向けて排出されるようになっている。   The EGR cooler 4 cools the EGR gas by heat exchange between the cooling water taken in from the circulation water channel 8 and the EGR gas. The EGR gas to be cooled flows into the EGR cooler 4 from the exhaust side of the engine 2 and exchanges heat with the cooling water, and is then discharged toward the intake side of the engine 2.

暖機用入口水路２３は、第１冷却水管１４とＥＧＲクーラ４の入口４３を接続する第１水路３２からなる。冷却用入口水路２２は、後述する第２水路３３より主回路３上流側の第３冷却水管２０と第１水路３２を接続する第３水路３４と、第３水路３４、ＥＧＲクーラ４間の第１水路３２とからなり、ラジエータ７から出た直後の循環水路８内で最も冷えた冷却水をＥＧＲクーラ４に導入するように設定されている。また、第３水路３４には第３冷却水管２０側から第１水路３２側に冷却水を送るＥＧＲクーラ用水ポンプ３５が設けられている。暖機用出口水路２５は、ＥＧＲクーラ４の出口４４と第３水路３４より主回路３下流側の第３冷却水管２０を接続する第２水路３３からなり、ＥＧＲクーラ４で暖められた冷却水をラジエータ７を通さずにエンジン６に帰して暖機時間を短縮するようになっている。冷却用出口水路２４は、第２水路３３とサーモスタット１０の主回路３下流側の第２冷却水管１７を接続する第４水路３６からなる。   The warm-up inlet water channel 23 includes a first water channel 32 that connects the first cooling water pipe 14 and the inlet 43 of the EGR cooler 4. The cooling inlet water channel 22 includes a third water channel 34 connecting the third cooling water pipe 20 and the first water channel 32 upstream of the main circuit 3 with respect to the second water channel 33 described later, and a third water channel 34 between the third water channel 34 and the EGR cooler 4. The cooling water that is the coldest in the circulation water channel 8 immediately after exiting the radiator 7 is set to be introduced into the EGR cooler 4. The third water passage 34 is provided with an EGR cooler water pump 35 for sending the cooling water from the third cooling water pipe 20 side to the first water passage 32 side. The warm-up outlet water channel 25 includes a second water channel 33 connecting the outlet 44 of the EGR cooler 4 and the third cooling water pipe 20 on the downstream side of the main circuit 3 from the third water channel 34, and the cooling water heated by the EGR cooler 4. The warm-up time is shortened by returning the engine to the engine 6 without passing through the radiator 7. The cooling outlet water channel 24 includes a fourth water channel 36 that connects the second water channel 33 and the second cooling water pipe 17 on the downstream side of the main circuit 3 of the thermostat 10.

入口側水路切替手段２６、２７は、第３水路３４との接続位置より上流側の第１水路３２を開閉する第１電磁バルブ２６と、ＥＧＲクーラ用水ポンプ３５下流側の第３水路３４を開閉する第２電磁バルブ２７とからなり、第１電磁バルブ２６又は第２電磁バルブ２７のいずれか一方を開き他方を閉じることで入口水路を冷却用入口水路２２又は暖機用入口水路２３のいずれか一方に切り替えられるようになっている。出口側水路切替手段２８、２９は、第４水路３６を開閉する第３電磁バルブ２８と、第４水路３６との接続位置より下流側の第２水路３３を開閉する第４電磁バルブ２９とからなり、第３電磁バルブ２８又は第４電磁バルブ２９のいずれか一方を開き他方を閉じることで出口水路を冷却用出口水路２４又は暖機用出口水路２５のいずれか一方に切り替えられるようになっている。   The inlet side water channel switching means 26 and 27 open and close the first electromagnetic valve 26 that opens and closes the first water channel 32 upstream of the connection position with the third water channel 34 and the third water channel 34 downstream of the EGR cooler water pump 35. The first electromagnetic valve 26 or the second electromagnetic valve 27 is opened, and either the first electromagnetic valve 26 or the second electromagnetic valve 27 is opened and the other is closed so that the inlet water channel is either the cooling inlet water channel 22 or the warm-up inlet water channel 23. It can be switched to one side. The outlet side water channel switching means 28, 29 includes a third electromagnetic valve 28 that opens and closes the fourth water channel 36, and a fourth electromagnetic valve 29 that opens and closes the second water channel 33 downstream from the connection position with the fourth water channel 36. Thus, the outlet water channel can be switched to either the cooling outlet water channel 24 or the warming-up outlet water channel 25 by opening one of the third electromagnetic valve 28 or the fourth electromagnetic valve 29 and closing the other. Yes.

水温検出手段３０は、第２冷却水管１７に設けられ測定したエンジン出口水温を電気信号として制御手段３１に入力する温度センサからなる。   The water temperature detection means 30 includes a temperature sensor that is provided in the second cooling water pipe 17 and inputs the measured engine outlet water temperature to the control means 31 as an electrical signal.

制御手段３１は、マイクロコンピュータからなり、水温検出手段３０の検出温度に基づいてＥＧＲクーラ用水ポンプ３５をオンオフ制御すると共に各電磁バルブ２６、２７、２８、２９を開閉制御するようになっている。具体的には、制御手段３１は、水温検出手段３０で検出された出口水温が所定温度以下のとき、ＥＧＲクーラ用水ポンプ３５を停止し、第１電磁バルブ２６と第４電磁バルブ２９を開弁すると共に、第２電磁バルブ２７と第３電磁バルブ２８を閉弁してエンジン用水ポンプ１１の吐出側からＥＧＲクーラ４に冷却水を導くと共に、ＥＧＲクーラ４にて暖められた冷却水をエンジン用水ポンプ１１の吸込側に戻す回路を形成するようになっている。そしてさらに制御手段３１は、水温検出手段３０で検出された出口水温が所定温度を超えるとき、ＥＧＲクーラ用水ポンプ３５を駆動し、第２電磁バルブ２７と第３電磁バルブ２８を開弁すると共に、第１電磁バルブ２６と第４電磁バルブ２９を閉弁してラジエータ７の出口１８側からＥＧＲクーラ４に冷却水を導くと共に、ＥＧＲクーラ４にて暖められた冷却水をラジエータ７の入口側に戻す回路を形成するようになっている。出口水温と比較する所定温度は、ＥＧＲクーラ４に関して暖機が終了したと判断できる温度（例えば５０℃）に設定されている。   The control means 31 is composed of a microcomputer, and controls the on / off of the EGR cooler water pump 35 based on the temperature detected by the water temperature detecting means 30 and also controls the opening and closing of the electromagnetic valves 26, 27, 28 and 29. Specifically, the control means 31 stops the EGR cooler water pump 35 and opens the first electromagnetic valve 26 and the fourth electromagnetic valve 29 when the outlet water temperature detected by the water temperature detection means 30 is equal to or lower than a predetermined temperature. At the same time, the second electromagnetic valve 27 and the third electromagnetic valve 28 are closed to guide the cooling water from the discharge side of the engine water pump 11 to the EGR cooler 4, and the cooling water heated by the EGR cooler 4 is supplied to the engine water. A circuit for returning to the suction side of the pump 11 is formed. Further, the control means 31 drives the EGR cooler water pump 35 to open the second electromagnetic valve 27 and the third electromagnetic valve 28 when the outlet water temperature detected by the water temperature detection means 30 exceeds a predetermined temperature, and The first electromagnetic valve 26 and the fourth electromagnetic valve 29 are closed to guide the cooling water from the outlet 18 side of the radiator 7 to the EGR cooler 4, and the cooling water heated by the EGR cooler 4 is introduced to the inlet side of the radiator 7. A return circuit is formed. The predetermined temperature to be compared with the outlet water temperature is set to a temperature (for example, 50 ° C.) at which it can be determined that the warm-up of the EGR cooler 4 has been completed.

次に本実施の形態の作用を述べる。   Next, the operation of this embodiment will be described.

図２に示すように、イグニッション用のキースイッチをオン３７すると、制御手段３１は可変設定値を読み込む等のイニシャライズ３８を行う。この後、制御手段３１は、水温検出手段３０にてエンジン出口水温Ｔｗの測定３９を行い、エンジン出口水温Ｔｗが所定温度Ｔ0より大きいか否かを判別４０する。 As shown in FIG. 2, when the ignition key switch is turned on 37, the control means 31 performs initialization 38 such as reading a variable set value. Thereafter, the control means 31 measures 39 the engine outlet water temperature Tw by the water temperature detecting means 30 and determines 40 whether or not the engine outlet water temperature Tw is higher than a predetermined temperature T 0 .

出口水温Ｔｗが所定温度Ｔ0以下である場合、図３に示すように、制御手段３１はＥＧＲクーラ用水ポンプ３５を停止し、暖機用入口水路２３と暖機用出口水路２５を開き、かつ、冷却用入口水路２２と冷却用出口水路２４を閉じるように水路切替手段２６、２７、２８、２９を作動させる。すなわち、制御手段３１はＥＧＲクーラ用水ポンプ３５を停止し、第１電磁バルブ２６と第４電磁バルブ２９を開弁すると共に、第２電磁バルブ２７と第３電磁バルブ２８を閉弁４１（図２参照）する。これによりエンジン用水ポンプ吐出口１２近傍の循環水路８からＥＧＲクーラ４に冷却水を導入し、ＥＧＲクーラ４を出た冷却水をエンジン用水ポンプ吸込口１９近傍の循環水路８に戻すことができる。そして、冷却水の水温がサーモスタット１０の設定温度に至るまでは、エンジン６側の冷却水はラジエータ７を通らずに全てエンジン６内部を循環するので、ＥＧＲガスより受けた熱を全てエンジン６に戻すことができ、暖機が促進される。また、暖機が促進されることでＥＧＲクーラ冷却水温度も早く上がり、ＥＧＲガスが過冷却される時間を大幅に短縮することができる。 When the outlet water temperature Tw is equal to or lower than the predetermined temperature T 0 , as shown in FIG. 3, the control means 31 stops the EGR cooler water pump 35, opens the warm-up inlet water channel 23 and the warm-up outlet water channel 25, and Then, the water channel switching means 26, 27, 28, 29 are operated so as to close the cooling inlet water channel 22 and the cooling outlet water channel 24. That is, the control means 31 stops the EGR cooler water pump 35, opens the first electromagnetic valve 26 and the fourth electromagnetic valve 29, and closes the second electromagnetic valve 27 and the third electromagnetic valve 28 (FIG. 2). refer. As a result, cooling water can be introduced into the EGR cooler 4 from the circulating water passage 8 in the vicinity of the engine water pump discharge port 12, and the cooling water exiting the EGR cooler 4 can be returned to the circulating water passage 8 in the vicinity of the engine water pump suction port 19. Until the coolant temperature reaches the set temperature of the thermostat 10, the coolant on the engine 6 side circulates entirely inside the engine 6 without passing through the radiator 7, so that all the heat received from the EGR gas is supplied to the engine 6. It can be returned and warm-up is promoted. Further, the warm-up is promoted, so that the temperature of the EGR cooler cooling water rises quickly, and the time during which the EGR gas is supercooled can be greatly shortened.

出口水温Ｔｗが所定温度Ｔ0を超えると、図４に示すように、制御手段３１はＥＧＲクーラ用水ポンプ３５を駆動し、冷却用入口水路２２と冷却用出口水路２４を開き、かつ、暖機用入口水路２３と暖機用出口水路２５を閉じるように水路切替手段２６、２７、２８、２９を作動させてＥＧＲクーラ冷却水の経路を変更する。すなわち、制御手段３１はＥＧＲクーラ用水ポンプ３５を駆動し、第２電磁バルブ２７と第３電磁バルブ２８を開弁すると共に、第１電磁バルブ２６と第４電磁バルブ２９を閉弁４２（図２参照）する。これによりラジエータ７の出口１８近傍の循環水路８からＥＧＲクーラ４に冷却水を導入し、ＥＧＲクーラ４にて暖められた冷却水をラジエータ７入口近傍の循環水路８に戻す配管に変更できる。この配管は、図７に示す従来の最も冷却能力が高い配管であり、ＮＯｘ低減性能を従来の最高水準にできる。 When the outlet water temperature Tw exceeds the predetermined temperature T 0 , as shown in FIG. 4, the control means 31 drives the EGR cooler water pump 35 to open the cooling inlet water passage 22 and the cooling outlet water passage 24, and The channel switching means 26, 27, 28 and 29 are operated so as to close the inlet water channel 23 and the warm-up outlet channel 25 to change the path of the EGR cooler cooling water. That is, the control means 31 drives the EGR cooler water pump 35, opens the second electromagnetic valve 27 and the third electromagnetic valve 28, and closes the first electromagnetic valve 26 and the fourth electromagnetic valve 29 (FIG. 2). refer. As a result, the cooling water can be introduced into the EGR cooler 4 from the circulation water passage 8 near the outlet 18 of the radiator 7 and the cooling water heated by the EGR cooler 4 can be changed to a pipe that returns to the circulation water passage 8 near the radiator 7 inlet. This pipe is the conventional pipe having the highest cooling capacity shown in FIG. 7, and can reduce the NOx reduction performance to the highest level in the past.

このように、第１冷却水管１４とＥＧＲクーラ４の入口４３を接続する第１水路３２と、ＥＧＲクーラ４の出口４４と第３冷却水管２０を接続する第２水路３３と、第２水路３３より上流側の第３冷却水管２０と第１水路３２とを接続する第３水路３４と、第２水路３３と前記サーモスタット１０の下流側の第２冷却水管１７を接続する第４水路３６と、前記第３水路３４より上流側の第１水路３２を開閉する第１電磁バルブ２６と、第４水路３６の下流側の第２水路３３を開閉する第４電磁バルブ２９と、第３水路３４に設けられ第３冷却水管２０側から第１水路３２側に冷却水を送るＥＧＲクーラ用水ポンプ３５と、ＥＧＲクーラ用水ポンプ３５の下流側の第３水路３４を開閉する第２電磁バルブ２７と、第４水路３６を開閉する第３電磁バルブ２８と、エンジン出口水温を検出する水温検出手段３０と、水温検出手段３０の検出温度に基づいてＥＧＲクーラ用水ポンプ３５をオンオフ制御すると共に各電磁バルブ２６、２７、２８、２９を開閉制御する制御手段３１とを備えてエンジン６の冷却水回路１を構成したため、エンジン始動後、エンジン水温が所定温度に達するまでＥＧＲクーラ冷却水の副回路５を用いてＥＧＲガスから放熱される熱量をエンジン６に帰すことができ、暖機時間を短縮でき、暖機終了後には、ＥＧＲクーラ冷却水の副回路５を変更し、ＥＧＲクーラ４の冷却能力を上げることができ、ＮＯｘの低減ができる。そしてこれにより、ＨＣの低減とＮＯｘの低減を高い水準で両立でき、ＥＧＲガスの過冷却によって生じるＥＧＲクーラ４内の汚損を低減できる。   As described above, the first water channel 32 connecting the first cooling water pipe 14 and the inlet 43 of the EGR cooler 4, the second water channel 33 connecting the outlet 44 of the EGR cooler 4 and the third cooling water tube 20, and the second water channel 33. A third water channel 34 connecting the third cooling water pipe 20 and the first water channel 32 on the more upstream side, a fourth water channel 36 connecting the second water channel 33 and the second cooling water pipe 17 on the downstream side of the thermostat 10, and The first electromagnetic valve 26 that opens and closes the first water passage 32 upstream of the third water passage 34, the fourth electromagnetic valve 29 that opens and closes the second water passage 33 downstream of the fourth water passage 36, and the third water passage 34 An EGR cooler water pump 35 that is provided and sends cooling water from the third cooling water pipe 20 side to the first water channel 32 side; a second electromagnetic valve 27 that opens and closes a third water channel 34 on the downstream side of the EGR cooler water pump 35; 4th electric train that opens and closes the four water channels 36 The EGR cooler water pump 35 is controlled to be turned on / off based on the detected temperature of the valve 28, the engine outlet water temperature, and the temperature detected by the water temperature detection means 30, and the electromagnetic valves 26, 27, 28, 29 are controlled to open and close. Since the cooling water circuit 1 of the engine 6 is configured with the control means 31, the amount of heat radiated from the EGR gas using the sub-circuit 5 of the EGR cooler cooling water after the engine is started until the engine water temperature reaches a predetermined temperature. 6, the warm-up time can be shortened, and after completion of the warm-up, the sub-circuit 5 of the EGR cooler cooling water can be changed, the cooling capacity of the EGR cooler 4 can be increased, and NOx can be reduced. As a result, both HC reduction and NOx reduction can be achieved at a high level, and fouling in the EGR cooler 4 caused by supercooling of the EGR gas can be reduced.

制御手段３１は、水温検出手段３０で検出された出口水温Ｔｗが所定温度Ｔ0以下のとき、ＥＧＲクーラ用水ポンプ３５を停止し、第１電磁バルブ２６と第４電磁バルブ２９を開弁すると共に、第２電磁バルブ２７と第３電磁バルブ２８を閉弁するものとしたため、簡単な構造で確実に入口水路を暖機用入口水路２３に切り替えることができると共に出口水路を暖機用出口水路２５に切り替えることができる。 When the outlet water temperature Tw detected by the water temperature detection means 30 is equal to or lower than the predetermined temperature T 0 , the control means 31 stops the EGR cooler water pump 35 and opens the first electromagnetic valve 26 and the fourth electromagnetic valve 29. Since the second electromagnetic valve 27 and the third electromagnetic valve 28 are closed, the inlet water channel can be reliably switched to the warm-up inlet water channel 23 with a simple structure and the outlet water channel can be switched to the warm-up outlet water channel 25. You can switch to

また、制御手段３１は、水温検出手段３０で検出された出口水温Ｔｗが所定温度Ｔ0を超えるとき、ＥＧＲクーラ用水ポンプ３５を駆動し、第２電磁バルブ２７と第３電磁バルブ２８を開弁すると共に、第１電磁バルブ２６と第４電磁バルブ２９を閉弁するものとしたため、簡単な構造で確実に入口水路を冷却用入口水路２２に切り替えることができると共に出口水路を冷却用出口水路２４に切り替えることができる。 Further, when the outlet water temperature Tw detected by the water temperature detection means 30 exceeds the predetermined temperature T 0 , the control means 31 drives the EGR cooler water pump 35 and opens the second electromagnetic valve 27 and the third electromagnetic valve 28. In addition, since the first electromagnetic valve 26 and the fourth electromagnetic valve 29 are closed, the inlet water channel can be reliably switched to the cooling inlet water channel 22 with a simple structure and the outlet water channel can be switched to the cooling outlet water channel 24. You can switch to

また、ラジエータ７の出口１８側の循環水路８からＥＧＲクーラ４に冷却水を取り込むための入口水路２２、２３と、ＥＧＲクーラ４からの冷却水をラジエータ７の入口側の循環水路８に戻すための冷却用出口水路２４と、ＥＧＲクーラ４からの冷却水をラジエータ７の出口１８側の循環水路８に戻すための暖機用出口水路２５と、ＥＧＲクーラ４の出口水路を冷却用出口水路２４又は暖機用出口水路２５のいずれか一方に切り替える出口側水路切替手段２８、２９と、循環水路８に設けられエンジン６の出口水温を検出する水温検出手段３０と、水温検出手段３０で検出された出口水温Ｔｗが所定温度Ｔ0を超えるとき冷却用出口水路２４を開き暖機用出口水路２５を閉じるように出口側水路切替手段２８、２９を作動させ、出口水温Ｔｗが所定温度Ｔ0以下のとき暖機用出口水路２５を開き冷却用出口水路２４を閉じるように出口側水路切替手段２８、２９を作動させる制御手段３１とを備えてエンジン６の冷却水回路１を構成したため、暖機時間を短縮でき、かつ、暖機終了後にＥＧＲクーラ４を充分冷却することができる。 In addition, inlet water passages 22 and 23 for taking cooling water from the circulating water passage 8 on the outlet 18 side of the radiator 7 into the EGR cooler 4 and cooling water from the EGR cooler 4 are returned to the circulating water passage 8 on the inlet side of the radiator 7. The cooling outlet water channel 24, the warming outlet water channel 25 for returning the cooling water from the EGR cooler 4 to the circulating water channel 8 on the outlet 18 side of the radiator 7, and the outlet water channel 24 for the EGR cooler 4 Or, the outlet side water channel switching means 28 and 29 for switching to any one of the warm-up outlet water paths 25, the water temperature detecting means 30 provided in the circulating water path 8 for detecting the outlet water temperature of the engine 6, and the water temperature detecting means 30 are detected. outlet water temperature Tw so that actuate the outlet side water passage switching means 28, 29 so as to close the cooling warming-up outlet waterway 25 to open the outlet water passage 24 when exceeding the predetermined temperature T 0, the outlet water temperature Tw The cooling water circuit 1 of the engine 6 and a control unit 31 for actuating the predetermined temperature T 0 exit-side water passage switching means 28, 29 so as to close the cooling outlet water passage 24 to open the warming-up outlet waterway 25 when following Since it comprised, warm-up time can be shortened and the EGR cooler 4 can fully be cooled after warm-up completion.

なお、ラジエータ７の出口１８側の循環水路８からＥＧＲクーラ４に冷却水を取り込むための入口水路は、上述したように暖機用入口水路２３と冷却用入口水路２２とのいずれか一方に切り替えることが好ましいが、いずれか一方の入口水路２２、２３を省略して切り替えないものとしても暖機時間を短縮でき、かつ、暖機終了後にＥＧＲクーラ４を図６に示す従来の冷却水回路５１と同等に充分冷却することができる。   Note that the inlet water channel for taking cooling water from the circulation water channel 8 on the outlet 18 side of the radiator 7 into the EGR cooler 4 is switched to either the warm-up inlet water channel 23 or the cooling inlet water channel 22 as described above. However, even if one of the inlet water channels 22 and 23 is omitted and not switched, the warm-up time can be shortened, and the EGR cooler 4 shown in FIG. Can be cooled as well as

本発明の好適実施の形態を示すエンジンの冷却水回路の回路図である。It is a circuit diagram of a cooling water circuit of an engine showing a preferred embodiment of the present invention. 制御手段の制御フローを示す流れ図である。It is a flowchart which shows the control flow of a control means. 暖機中の冷却水の流れを示す説明図である。It is explanatory drawing which shows the flow of the cooling water during warming-up. 暖機終了後の冷却水の流れを示す説明図である。It is explanatory drawing which shows the flow of the cooling water after completion | finish of warming-up. 従来のエンジンの冷却水回路の回路図である。It is a circuit diagram of the cooling water circuit of the conventional engine. 従来のエンジンの冷却水回路の回路図である。It is a circuit diagram of the cooling water circuit of the conventional engine. 従来のエンジンの冷却水回路の回路図である。It is a circuit diagram of the cooling water circuit of the conventional engine.

符号の説明Explanation of symbols

１ 冷却水回路
４ ＥＧＲクーラ
６ エンジンウォータジャケット
７ ラジエータ
１０ サーモスタット
１１ エンジン用水ポンプ
１２ 吐出口
１３ 入口
１４ 第１冷却水管
１７ 第２冷却水管
１８ 出口
１９ 吸込口
２０ 第３冷却水管
２１ バイパス水管
２６ 第１電磁バルブ
２７ 第２電磁バルブ
２８ 第３電磁バルブ
２９ 第４電磁バルブ
３０ 水温検出手段
３１ 制御手段
３２ 第１水路
３３ 第２水路
３４ 第３水路
３５ ＥＧＲクーラ用水ポンプ
３６ 第４水路
４３ 入口
４４ 出口 1 Cooling Water Circuit 4 EGR Cooler 6 Engine Water Jacket 7 Radiator 10 Thermostat 11 Engine Water Pump 12 Discharge Port 13 Inlet 14 First Cooling Water Pipe 17 Second Cooling Water Pipe 18 Outlet 19 Suction Port 20 Third Cooling Water Pipe 21 Bypass Water Pipe 26 First Electromagnetic valve 27 Second electromagnetic valve 28 Third electromagnetic valve 29 Fourth electromagnetic valve 30 Water temperature detecting means 31 Control means 32 First water passage 33 Second water passage 34 Third water passage 35 EGR cooler water pump 36 Fourth water passage 43 Inlet 44 Outlet

Claims (4)

エンジン用水ポンプの吐出口とエンジンウォータジャケットの入口を接続する第１冷却水管と、前記エンジンウォータジャケットの出口とラジエータの入口を接続する第２冷却水管と、前記ラジエータの出口と前記エンジン用水ポンプの吸込口を接続する第３冷却水管と、前記第２冷却水管と前記第３冷却水管を接続するバイパス水管と、冷却水の水温が所定温度に満たないとき前記バイパス水管に冷却水を流通させると共にラジエータへの冷却水の流通を止め、前記水温が所定温度以上のとき前記バイパス水管への冷却水の流通を止めると共にラジエータに冷却水を流通させるサーモスタットと、前記いずれかの冷却水管から冷却水を取り込んでＥＧＲガスとの熱交換を行うＥＧＲクーラとを備えたエンジンの冷却水回路において、前記第１冷却水管とＥＧＲクーラの入口を接続する第１水路と、前記ＥＧＲクーラの出口と第３冷却水管を接続する第２水路と、該第２水路より上流側の第３冷却水管と前記第１水路とを接続する第３水路と、前記第２水路と前記サーモスタットの下流側の第２冷却水管を接続する第４水路と、前記第３水路より上流側の第１水路を開閉する第１電磁バルブと、第４水路の下流側の第２水路を開閉する第４電磁バルブと、第３水路に設けられ第３冷却水管側から第１水路側に冷却水を送るＥＧＲクーラ用水ポンプと、該ＥＧＲクーラ用水ポンプの下流側の第３水路を開閉する第２電磁バルブと、前記第４水路を開閉する第３電磁バルブと、エンジン出口水温を検出する水温検出手段と、該水温検出手段の検出温度に基づいて前記ＥＧＲクーラ用水ポンプをオンオフ制御すると共に前記各電磁バルブを開閉制御する制御手段とを備えることを特徴とするエンジンの冷却水回路。   A first cooling water pipe connecting the discharge port of the engine water pump and the inlet of the engine water jacket, a second cooling water pipe connecting the outlet of the engine water jacket and the inlet of the radiator, the outlet of the radiator and the water pump of the engine A third cooling water pipe connecting the suction port, a bypass water pipe connecting the second cooling water pipe and the third cooling water pipe, and circulating the cooling water through the bypass water pipe when the temperature of the cooling water does not reach a predetermined temperature. Stop the flow of the cooling water to the radiator, stop the flow of the cooling water to the bypass water pipe when the water temperature is equal to or higher than the predetermined temperature, and flow the cooling water to the radiator, and the cooling water from any one of the cooling water pipes An engine cooling water circuit including an EGR cooler that takes in and exchanges heat with EGR gas. A first water passage connecting the cooling water pipe and the inlet of the EGR cooler; a second water passage connecting the outlet of the EGR cooler and the third cooling water pipe; a third cooling water pipe upstream of the second water passage; and the first water passage. A third water channel connecting the second water channel and a fourth water channel connecting the second cooling water pipe downstream of the thermostat, and a first electromagnetic valve opening and closing the first water channel upstream of the third water channel A fourth electromagnetic valve that opens and closes the second water channel downstream of the fourth water channel, an EGR cooler water pump that is provided in the third water channel and sends cooling water from the third cooling water pipe side to the first water channel side, and the EGR A second electromagnetic valve for opening and closing a third water passage downstream of the cooler water pump; a third electromagnetic valve for opening and closing the fourth water passage; a water temperature detecting means for detecting an engine outlet water temperature; and a detected temperature of the water temperature detecting means. Based on the EGR cooler water port Cooling water circuit of the engine, characterized in that it comprises a control means for the opening and closing control of each solenoid valve with on-off control of the flop. 前記制御手段は、前記水温検出手段で検出された出口水温が所定温度以下のとき、前記エンジン用水ポンプの吐出側からＥＧＲクーラに冷却水を導くと共に、ＥＧＲクーラにて暖められた冷却水をエンジン用水ポンプの吸込側に戻す回路を形成すべく、前記ＥＧＲクーラ用水ポンプを停止し、前記第１電磁バルブと第４電磁バルブを開弁すると共に、前記第２電磁バルブと第３電磁バルブを閉弁することを特徴とする請求項１記載のエンジンの冷却水回路。   The control means guides the cooling water from the discharge side of the engine water pump to the EGR cooler when the outlet water temperature detected by the water temperature detecting means is equal to or lower than a predetermined temperature, and supplies the cooling water warmed by the EGR cooler to the engine. In order to form a circuit for returning to the suction side of the water pump, the EGR cooler water pump is stopped, the first electromagnetic valve and the fourth electromagnetic valve are opened, and the second electromagnetic valve and the third electromagnetic valve are closed. 2. The engine coolant circuit according to claim 1, wherein the engine coolant circuit is provided. 前記制御手段は、前記水温検出手段で検出された出口水温が所定温度を超えるとき、前記ラジエータの出口側からＥＧＲクーラに冷却水を導くと共に、ＥＧＲクーラにて暖められた冷却水をラジエータの入口側に戻す回路を形成すべく、前記ＥＧＲクーラ用水ポンプを駆動し、前記第２電磁バルブと第３電磁バルブを開弁すると共に、前記第１電磁バルブと第４電磁バルブを閉弁することを特徴とする請求項１又は２記載のエンジンの冷却水回路。   When the outlet water temperature detected by the water temperature detection means exceeds a predetermined temperature, the control means guides the cooling water from the outlet side of the radiator to the EGR cooler, and supplies the cooling water warmed by the EGR cooler to the inlet of the radiator Driving the EGR cooler water pump to open the second electromagnetic valve and the third electromagnetic valve, and closing the first electromagnetic valve and the fourth electromagnetic valve to form a circuit for returning to the side. The engine cooling water circuit according to claim 1 or 2, characterized in that エンジンウォータジャケット、ラジエータ間で冷却水を循環させる循環水路と、前記ラジエータの上流側の循環水路と下流側の循環水路を接続するバイパス水路と、冷却水の水温が所定温度に満たないときバイパス水路に冷却水を流通させると共にラジエータへの冷却水の流通を止め、前記水温が所定温度以上のとき前記バイパス水路への冷却水の流通を止めると共にラジエータに冷却水を流通させるサーモスタットと、前記循環水路に前記バイパス水路よりもエンジン側に位置して設けられ冷却水を循環させるエンジン用水ポンプと、前記循環水路から冷却水を取り込んでＥＧＲガスとの熱交換を行うＥＧＲクーラとを備えたエンジンの冷却水回路において、前記ラジエータの出口側の循環水路から前記ＥＧＲクーラに冷却水を取り込むための入口水路と、前記ＥＧＲクーラからの冷却水を前記ラジエータの入口側の循環水路に戻すための冷却用出口水路と、前記ＥＧＲクーラからの冷却水を前記ラジエータの出口側の循環水路に戻すための暖機用出口水路と、前記ＥＧＲクーラの出口水路を前記冷却用出口水路又は前記暖機用出口水路のいずれか一方に切り替える水路切替手段と、前記循環水路に設けられエンジンの出口水温を検出する水温検出手段と、該水温検出手段で検出された出口水温が所定温度を超えるとき前記冷却用出口水路を開き前記暖機用出口水路を閉じるように前記水路切替手段を作動させ、前記出口水温が所定温度以下のとき前記暖機用出口水路を開き前記冷却用出口水路を閉じるように前記水路切替手段を作動させる制御手段とを備えることを特徴とするエンジンの冷却水回路。   An engine water jacket, a circulation channel for circulating cooling water between the radiator, a bypass channel connecting the upstream circulation channel and the downstream circulation channel of the radiator, and a bypass channel when the coolant temperature does not reach a predetermined temperature A thermostat that circulates cooling water to the radiator and stops circulation of the cooling water to the radiator, stops the circulation of cooling water to the bypass water channel when the water temperature is equal to or higher than a predetermined temperature, and circulates the cooling water to the radiator, and the circulation water channel An engine water pump that is provided on the engine side of the bypass water passage and circulates the cooling water, and an EGR cooler that takes in the cooling water from the circulation water passage and performs heat exchange with the EGR gas. In the water circuit, cooling water was taken into the EGR cooler from the circulation water channel on the outlet side of the radiator. An inlet water channel, a cooling water channel for returning cooling water from the EGR cooler to the circulating water channel on the radiator inlet side, and a cooling water channel from the EGR cooler to return to the circulating water channel on the outlet side of the radiator An outlet water channel for warming up, a water channel switching means for switching the outlet water channel of the EGR cooler to either the cooling water channel for cooling or the outlet water channel for warming up, and detecting the outlet water temperature of the engine provided in the circulating water channel Water temperature detecting means, and when the outlet water temperature detected by the water temperature detecting means exceeds a predetermined temperature, operates the water channel switching means to open the cooling outlet water channel and close the warm-up outlet water channel, Control means for operating the water channel switching means so as to open the warm-up outlet water channel and close the cooling outlet water channel when the temperature is equal to or lower than a predetermined temperature. Cooling water circuit of the engine.
JP2006090840A 2006-03-29 2006-03-29 Engine coolant circuit Expired - Fee Related JP4802811B2 (en)

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