JP2012087737A - Intake air cooling device of two-stage supercharging system - Google Patents

Intake air cooling device of two-stage supercharging system Download PDF

Info

Publication number
JP2012087737A
JP2012087737A JP2010236825A JP2010236825A JP2012087737A JP 2012087737 A JP2012087737 A JP 2012087737A JP 2010236825 A JP2010236825 A JP 2010236825A JP 2010236825 A JP2010236825 A JP 2010236825A JP 2012087737 A JP2012087737 A JP 2012087737A
Authority
JP
Japan
Prior art keywords
intake air
cooling water
cooling
temperature
cooled
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2010236825A
Other languages
Japanese (ja)
Other versions
JP5614235B2 (en
Inventor
Akira Iijima
章 飯島
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Isuzu Motors Ltd
Original Assignee
Isuzu Motors Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Isuzu Motors Ltd filed Critical Isuzu Motors Ltd
Priority to JP2010236825A priority Critical patent/JP5614235B2/en
Publication of JP2012087737A publication Critical patent/JP2012087737A/en
Application granted granted Critical
Publication of JP5614235B2 publication Critical patent/JP5614235B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Landscapes

  • Supercharger (AREA)

Abstract

PROBLEM TO BE SOLVED: To suppress a deterioration in fuel economy of an engine by restraining efficiency reduction in a two-stage supercharging system, in an intake air cooling device of the two-stage supercharging system.SOLUTION: This intake air cooling device 1 of the two-stage supercharging system 30 having a high pressure stage supercharger 32 and a low pressure stage supercharger 33, includes an intake air cooling means 10, a cooling water cooling means 12, a cooling water circulating circuit 11, a bypass passage 14 for bypassing cooling water from the intake air cooling means 10, a cooling determining means 20 for determining whether or not intake air is cooled by heat exchange with the cooling water, and flow passage switching means 15 and 22 for switching a flow passage to the bypass passage 14 when determining that the intake air is not cooled by the cooling water and switching the flow passage to the intake air cooling means 10 when determining that the intake air is cooled by the cooling water.

Description

本発明は、低圧段過給機と高圧段過給機とを有する二段過給システムの吸気冷却装置に関し、特に低圧段過給機で圧縮された低圧吸気を冷却する水冷式のインタークーラを備えた二段過給システムの吸気冷却装置に関する。   The present invention relates to an intake air cooling device for a two-stage turbocharging system having a low-pressure stage supercharger and a high-pressure stage supercharger, and more particularly to a water-cooled intercooler that cools low-pressure intake air compressed by a low-pressure stage turbocharger. The present invention relates to an intake air cooling device for a two-stage supercharging system.

ディーゼルエンジン等の内燃機関（以下、エンジンという）では、エンジンのダウンサイジングに伴い、高出力低燃費化を図る二段過給システムが提案されている。通常、この二段過給システムは低圧段ターボチャージャと高圧段ターボチャージャとを有する二段過給システムであり、ターボチャージャの総合効率を上げるために低圧段ターボチャージャと高圧段ターボチャージャとの間に水冷式の冷却器（以下、インタークーラという）が配設されている。   2. Description of the Related Art In internal combustion engines such as diesel engines (hereinafter referred to as engines), a two-stage turbocharging system has been proposed that achieves high output and low fuel consumption as the engine is downsized. Usually, this two-stage turbocharging system is a two-stage turbocharger system having a low-pressure stage turbocharger and a high-pressure stage turbocharger, and between the low-pressure stage turbocharger and the high-pressure stage turbocharger in order to increase the overall efficiency of the turbocharger. In addition, a water-cooled cooler (hereinafter referred to as an intercooler) is disposed.

例えば、特許文献１には、高圧段ターボチャージャと低圧段ターボチャージャとを有する二段過給システムにおいて、吸気通路に低圧段ターボチャージャで圧縮された吸気を冷却するインタークーラを設けた構成が開示されている。   For example, Patent Document 1 discloses a configuration in which an intercooler for cooling intake air compressed by a low-pressure stage turbocharger is provided in an intake passage in a two-stage turbocharging system having a high-pressure stage turbocharger and a low-pressure stage turbocharger. Has been.

特開２００６−９０２０５号公報JP 2006-90205 A

一般的に、インタークーラは水冷式であって、低圧段ターボチャージャで圧縮されてインタークーラを通過する吸気（以下、低圧段出口吸気という）は、エンジンとは別系統の冷却水回路から供給される冷却水との熱交換により冷却される。より具体的には、インタークーラにはサブラジエータで外気との熱交換により冷却された冷却水が供給されており、係る冷却水によりインタークーラを通過する低圧吸気を冷却すると共に、低圧段出口吸気との熱交換で昇温された冷却水を再びサブラジエータに戻している。   In general, the intercooler is water-cooled, and intake air that is compressed by a low-pressure stage turbocharger and passes through the intercooler (hereinafter referred to as low-pressure stage outlet intake air) is supplied from a cooling water circuit that is separate from the engine. It is cooled by heat exchange with cooling water. More specifically, the intercooler is supplied with cooling water cooled by heat exchange with the outside air by the sub-radiator, and the low-pressure intake air passing through the intercooler is cooled by the cooling water, and the low-pressure stage outlet intake air is cooled. The cooling water whose temperature has been raised by heat exchange with the sub-radiator is returned again.

ところで、エンジンの高負荷運転時は、エンジンからの排気エネルギーにより低圧段コンプレッサが高速回転するので、低圧段出口吸気の温度は冷却水の温度よりも高くなる。そのため、エンジンの高負荷運転時は、低圧段出口吸気が冷却水との熱交換により昇温されることはなく、狙い通りに冷却される。一方、エンジンの部分負荷運転中は、低圧段ターボチャージャによる過給が低いため、冷却水の温度が低圧段出口吸気の温度よりも高くなる場合がある。そのため、エンジンの部分負荷運転時は、低圧段出口吸気が冷却水との熱交換により昇温されることとなり、かえって二段過給システムの総合効率が低下して、エンジンの燃費も悪化する可能性がある。   By the way, during high-load operation of the engine, the low-pressure stage compressor rotates at high speed due to the exhaust energy from the engine, so the temperature of the low-pressure stage outlet intake air becomes higher than the temperature of the cooling water. For this reason, during high-load operation of the engine, the low-pressure stage outlet intake air is not heated by heat exchange with the cooling water, and is cooled as intended. On the other hand, during the partial load operation of the engine, the supercharging by the low-pressure stage turbocharger is low, so the temperature of the cooling water may be higher than the temperature of the low-pressure stage outlet intake air. Therefore, during partial load operation of the engine, the intake pressure at the low-pressure stage outlet is raised by heat exchange with the cooling water, and instead the overall efficiency of the two-stage turbocharging system is lowered, and the fuel efficiency of the engine can be deteriorated. There is sex.

本発明は、このような点に鑑みてなされたもので、その目的は、二段過給システムの吸気冷却装置において、エンジンの運転領域全域で二段過給システムの総合効率の低下を抑制するとともに、エンジンの燃費悪化も効果的に抑止することにある。   The present invention has been made in view of the above points, and an object of the present invention is to suppress a decrease in the overall efficiency of the two-stage turbocharging system in the entire operation region of the engine in the intake air cooling device of the two-stage turbocharging system. At the same time, it is to effectively suppress the deterioration of the fuel consumption of the engine.

上記目的を達成するため、本発明の二段過給システムの吸気冷却装置は、内燃機関からの排気で駆動する低圧段過給機と高圧段過給機とを有する二段過給システムの吸気冷却装置であって、前記低圧段過給機と前記高圧段過給機との間の吸気通路に設けられ、該吸気通路を流れる吸気を冷却水との熱交換により冷却する吸気冷却手段と、前記冷却水を外気との熱交換により冷却する冷却水冷却手段と、前記冷却水冷却手段を通過した冷却水を前記吸気冷却手段に供給するとともに前記冷却水冷却手段へと戻す冷却水循環回路と、前記冷却水循環回路に設けられ、前記冷却水を前記吸気冷却手段からバイパスさせるバイパス通路と、前記吸気が前記冷却水との熱交換により冷却されるか否かを判定する冷却判定手段と、前記冷却判定手段の判定に応じて、前記吸気が前記冷却水により冷却されないと判定された場合は前記冷却水の流路を前記バイパス通路に切替え、かつ、前記吸気が前記冷却水により冷却されると判定された場合は前記冷却水の流路を前記吸気冷却手段に切替える流路切替手段とを有することを特徴とする。   In order to achieve the above object, an intake air cooling apparatus for a two-stage turbocharging system according to the present invention includes an intake air of a two-stage turbocharging system having a low-pressure supercharger and a high-pressure supercharger that are driven by exhaust from an internal combustion engine. An intake air cooling means provided in an intake passage between the low-pressure stage supercharger and the high-pressure stage supercharger for cooling the intake air flowing through the intake passage by heat exchange with cooling water; A cooling water cooling means for cooling the cooling water by heat exchange with outside air, a cooling water circulation circuit for supplying the cooling water that has passed through the cooling water cooling means to the intake air cooling means and returning the cooling water to the cooling water cooling means, A bypass passage provided in the cooling water circulation circuit for bypassing the cooling water from the intake air cooling means; a cooling determination means for determining whether or not the intake air is cooled by heat exchange with the cooling water; and the cooling Judgment of judgment means Accordingly, when it is determined that the intake air is not cooled by the cooling water, the flow path of the cooling water is switched to the bypass passage, and when it is determined that the intake air is cooled by the cooling water, And a flow path switching means for switching the cooling water flow path to the intake air cooling means.

また、前記冷却判定手段は、前記吸気冷却手段よりも上流側に位置する前記吸気通路を流れる吸気温度を検出する第１温度検出手段と、前記吸気冷却手段よりも下流側に位置する前記吸気通路を流れる吸気温度を検出する第２温度検出手段とを有するとともに、前記第２温度検出手段の検出値が前記第１温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第２温度検出手段の検出値が前記第１温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定するようにしてもよい。   The cooling determination means includes a first temperature detection means for detecting an intake air temperature flowing through the intake passage located upstream of the intake air cooling means, and the intake passage located downstream of the intake air cooling means. And a second temperature detection means for detecting the temperature of the intake air flowing through the intake air, and when the detection value of the second temperature detection means is smaller than the detection value of the first temperature detection means, the intake air is cooled by the cooling water. If the detection value of the second temperature detection means is equal to or higher than the detection value of the first temperature detection means, it may be determined that the intake air is not cooled by the cooling water.

また、前記冷却判定手段は、前記吸気冷却手段よりも上流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第３温度検出手段と、前記吸気冷却手段よりも下流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第４温度検出手段とを有するとともに、前記第３温度検出手段の検出値が前記第４温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第３温度検出手段の検出値が前記第４温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定するようにしてもよい。   The cooling determination means includes a third temperature detection means for detecting a coolant temperature flowing through the cooling water circulation circuit located upstream of the intake air cooling means, and the downstream position of the intake air cooling means. And a fourth temperature detecting means for detecting a temperature of the cooling water flowing through the cooling water circulation circuit, and when the detected value of the third temperature detecting means is smaller than the detected value of the fourth temperature detecting means, the intake air is cooled. If it is determined that the water is cooled, and if the detected value of the third temperature detecting means is equal to or higher than the detected value of the fourth temperature detecting means, it is determined that the intake air is not cooled by the cooling water. Good.

また、前記冷却判定手段は、前記吸気冷却手段よりも上流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第５温度検出手段と、前記吸気冷却手段よりも上流側に位置する前記吸気通路を流れる吸気温度を検出する第６温度検出手段とを有するとともに、前記第５温度検出手段の検出値が前記第６温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第５温度検出手段の検出値が前記第６温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定するようにしてもよい。   The cooling determination means includes fifth temperature detection means for detecting a temperature of cooling water flowing through the cooling water circulation circuit located upstream of the intake air cooling means, and the upstream position of the intake air cooling means. A sixth temperature detecting means for detecting the temperature of the intake air flowing through the intake passage, and when the detected value of the fifth temperature detecting means is smaller than the detected value of the sixth temperature detecting means, the intake air is caused by the cooling water. It may be determined that the intake air is not cooled by the cooling water when it is determined that the cooling is performed and the detection value of the fifth temperature detection unit is equal to or greater than the detection value of the sixth temperature detection unit.

本発明の二段過給システムの吸気冷却装置によれば、エンジンの運転領域全域で二段過給システムの総合効率の低下を抑制することができるとともに、エンジンの燃費悪化も効果的に抑止することができる。   According to the intake air cooling device of the two-stage turbocharging system of the present invention, it is possible to suppress a decrease in the overall efficiency of the two-stage turbocharging system in the entire operation region of the engine, and also effectively suppress the deterioration of the fuel consumption of the engine. be able to.

本発明の第一実施形態に係る二段過給システムの吸気冷却装置を示す概略図である。It is the schematic which shows the intake air cooling device of the two-stage supercharging system which concerns on 1st embodiment of this invention. 本発明の第一実施形態に係る切替バルブを示す模式的な部分断面図である。It is a typical fragmentary sectional view showing the change valve concerning a first embodiment of the present invention. 本発明の第一実施形態に係る二段過給システムの吸気冷却装置による制御内容を示すフローチャートである。It is a flowchart which shows the control content by the intake air cooling device of the two-stage supercharging system which concerns on 1st embodiment of this invention. 本発明の第二実施形態に係る二段過給システムの吸気冷却装置を示す概略図である。It is the schematic which shows the intake air cooling device of the two-stage supercharging system which concerns on 2nd embodiment of this invention. 本発明の第二実施形態に係る二段過給システムの吸気冷却装置による制御内容を示すフローチャートである。It is a flowchart which shows the control content by the intake air cooling device of the two-stage supercharging system which concerns on 2nd embodiment of this invention. 本発明の第三実施形態に係る二段過給システムの吸気冷却装置を示す概略図である。It is the schematic which shows the intake air cooling device of the two-stage supercharging system which concerns on 3rd embodiment of this invention. 本発明の第三実施形態に係る二段過給システムの吸気冷却装置による制御内容を示すフローチャートである。It is a flowchart which shows the control content by the intake air cooling device of the two-stage supercharging system which concerns on 3rd embodiment of this invention.

以下、図面により、本発明に係る各実施形態について説明する。   Embodiments according to the present invention will be described below with reference to the drawings.

＜第一実施形態＞
図１〜３は、本発明の第一実施形態に係る二段過給システムの吸気冷却装置１を説明するものである。同一の部品には同一の符号を付してあり、それらの名称および機能も同じである。したがって、それらについての詳細な説明は繰返さない。 <First embodiment>
1-3 illustrate the intake air cooling device 1 of the two-stage supercharging system according to the first embodiment of the present invention. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

まず、本実施形態に係る吸気冷却装置１が適用される二段過給システム３０から説明する。図１に示すように、二段過給システム３０はディーゼルエンジン等の内燃機関（以下、エンジンという）３１の排気エネルギーを利用してエンジン３１に吸気を圧縮供給する高圧段ターボチャージャ（高圧段過給機）３２と、この高圧段ターボチャージャ３２よりも大容量の低圧段ターボチャージャ（低圧段過給機）３３とを備えている。   First, the two-stage supercharging system 30 to which the intake air cooling device 1 according to the present embodiment is applied will be described. As shown in FIG. 1, a two-stage turbocharging system 30 uses a high-pressure turbocharger (high-pressure supercharger) that compresses and supplies intake air to an engine 31 using exhaust energy of an internal combustion engine (hereinafter referred to as an engine) 31 such as a diesel engine. And a low-pressure stage turbocharger (low-pressure stage supercharger) 33 having a larger capacity than the high-pressure stage turbocharger 32.

エンジン３１には、図１に示すように、吸気マニホールド３４と排気マニホールド３５とが設けられている。また、吸気マニホールド３４には、吸気弁３１ａの開弁により高圧段ターボチャージャ３２から送出される高圧吸気を導入する高圧吸気通路３６が接続され、排気マニホールド３５には、排気弁３１ｂの開弁により排気を排出する第１排気通路３７が接続されている。   As shown in FIG. 1, the engine 31 is provided with an intake manifold 34 and an exhaust manifold 35. The intake manifold 34 is connected to a high-pressure intake passage 36 for introducing high-pressure intake air sent from the high-pressure turbocharger 32 by opening the intake valve 31a, and the exhaust manifold 35 is opened by opening the exhaust valve 31b. A first exhaust passage 37 for discharging the exhaust is connected.

高圧段ターボチャージャ３２は、図１に示すように、高圧吸気通路３６の上流側に設けられた高圧段コンプレッサ３２ａと、第１排気通路３７の下流側に設けられた高圧段タービン３２ｂとを有する。また、高圧段タービン３２ｂの下流側には第２排気通路３８が設けられている。そして、高圧段ターボチャージャ３２は、高圧段タービン３２ｂがエンジン３１からの排気エネルギーを利用して高圧段コンプレッサ３２ａを回転駆動することで、後述する低圧段コンプレッサ３３ａで圧縮された低圧吸気を更に圧縮してエンジン３１へと供給するように構成されている。   As shown in FIG. 1, the high-pressure turbocharger 32 includes a high-pressure compressor 32 a provided on the upstream side of the high-pressure intake passage 36 and a high-pressure turbine 32 b provided on the downstream side of the first exhaust passage 37. . A second exhaust passage 38 is provided on the downstream side of the high-pressure turbine 32b. The high-pressure stage turbocharger 32 further compresses the low-pressure intake air compressed by the low-pressure stage compressor 33a, which will be described later, by the high-pressure stage turbine 32b rotationally driving the high-pressure stage compressor 32a using the exhaust energy from the engine 31. Thus, the engine 31 is configured to be supplied.

低圧段ターボチャージャ３３は、図１に示すように、高圧段コンプレッサ３２ａに低圧段出口吸気通路３９で接続された低圧段コンプレッサ３３ａと、第２排気通路３８の下流側に設けられた低圧段タービン３３ｂとを有する。また、低圧段コンプレッサ３３ａの上流側は吸気通路４０を介してエアクリーナ４１と接続されている。すなわち、低圧段ターボチャージャ３３は、エンジン３１からの排気エネルギーで低圧段タービン３３ｂが駆動されると共に、同軸に設けられた低圧段コンプレッサ３３ａによりエアクリーナ４１から吸気通路４０を介して導入される新気を圧縮して高圧段コンプレッサ３２ｂへと送出するように構成されている。   As shown in FIG. 1, the low-pressure stage turbocharger 33 includes a low-pressure stage compressor 33a connected to the high-pressure stage compressor 32a via a low-pressure stage outlet intake passage 39, and a low-pressure stage turbine provided downstream of the second exhaust passage 38. 33b. Further, the upstream side of the low-pressure compressor 33 a is connected to an air cleaner 41 via an intake passage 40. That is, in the low-pressure stage turbocharger 33, the low-pressure stage turbine 33b is driven by the exhaust energy from the engine 31, and the fresh air introduced from the air cleaner 41 through the intake passage 40 by the low-pressure stage compressor 33a provided coaxially. Is compressed and sent to the high-pressure compressor 32b.

次に、本実施形態に係る吸気冷却装置１を説明する。吸気冷却装置１は、図１に示すように、インタークーラ（吸気冷却手段）１０と、冷却水循環回路１１と、サブラジエータ（冷却水冷却手段）１２と、ウォータポンプ１３と、バイパス通路１４と、切替バルブ１５と、第１吸気温センサ（第１温度検出手段）１６と、第２吸気温センサ（第２温度検出手段）１７とＥＣＵ２０とを備える。   Next, the intake air cooling device 1 according to the present embodiment will be described. As shown in FIG. 1, the intake air cooling device 1 includes an intercooler (intake air cooling means) 10, a cooling water circulation circuit 11, a sub-radiator (cooling water cooling means) 12, a water pump 13, a bypass passage 14, A switching valve 15, a first intake air temperature sensor (first temperature detection means) 16, a second intake air temperature sensor (second temperature detection means) 17, and an ECU 20 are provided.

インタークーラ１０は、図１に示すように、低圧段出口吸気通路３９に介装されている。そして、インタークーラ１０は、低圧段コンプレッサ３３ａで圧縮されて低圧段出口吸気通路３９を流れる低圧吸気を、サブラジエータ１２から冷却水循環回路１１を介して供給される冷却水との熱交換により冷却する。   As shown in FIG. 1, the intercooler 10 is interposed in the low-pressure stage outlet intake passage 39. The intercooler 10 cools the low-pressure intake air that is compressed by the low-pressure compressor 33a and flows through the low-pressure outlet air passage 39 by heat exchange with the cooling water supplied from the sub radiator 12 via the cooling water circulation circuit 11. .

冷却水循環回路１１は、図１に示すように、サブラジエータ１２の出口部１２ｂとインタークーラ１０の入口部１０ａとを接続するとともに、インタークーラ１０の出口部１０ｂとサブラジエータ１２の入口部１２ａとを接続する。また、冷却水循環回路１１には、冷却水循環回路１１内に冷却水を循環させるウォータポンプ１３が設けられている。すなわち、冷却水循環回路１１は、ウォータポンプ１３の稼働によりサブラジエータ１２を通過した冷却水をインタークーラ１０に供給するとともに、インタークーラ１０を通過した冷却水をサブラジエータ１２へ戻すように構成されている。また、冷却水循環回路１１には、図示しないＥＧＲ通路内を流れる環流排気を冷却するＥＧＲクーラ４２が介装されている。さらに、冷却水循環回路１１には、図１に示すように、冷却水の流路をインタークーラ１０から迂回させるバイパス通路１４が設けられている。   As shown in FIG. 1, the cooling water circulation circuit 11 connects the outlet portion 12 b of the sub radiator 12 and the inlet portion 10 a of the intercooler 10, and connects the outlet portion 10 b of the intercooler 10 and the inlet portion 12 a of the sub radiator 12. Connect. The cooling water circulation circuit 11 is provided with a water pump 13 that circulates the cooling water in the cooling water circulation circuit 11. That is, the cooling water circulation circuit 11 is configured to supply the cooling water that has passed through the sub-radiator 12 to the intercooler 10 by the operation of the water pump 13 and to return the cooling water that has passed through the inter-cooler 10 to the sub-radiator 12. Yes. Further, an EGR cooler 42 that cools the recirculated exhaust gas flowing in the EGR passage (not shown) is interposed in the cooling water circulation circuit 11. Further, as shown in FIG. 1, the coolant circulation circuit 11 is provided with a bypass passage 14 that bypasses the coolant flow path from the intercooler 10.

バイパス通路１４は、図１に示すように、一端をサブラジエータ１２の出口部１２ｂとインタークーラ１０の入口部１０ａとの間の冷却水循環回路１１に接続され、他端をインタークーラ１０の出口部１０ｂとサブラジエータ１２の入口部１２ａとの間の冷却水循環回路１１に接続されている。また、バイパス通路１４の上流側と冷却水循環回路１１との接続部には切替バルブ１５が設けられている。   As shown in FIG. 1, the bypass passage 14 has one end connected to the cooling water circulation circuit 11 between the outlet portion 12 b of the sub-radiator 12 and the inlet portion 10 a of the intercooler 10, and the other end connected to the outlet portion of the intercooler 10. The cooling water circulation circuit 11 is connected between 10 b and the inlet 12 a of the sub-radiator 12. Further, a switching valve 15 is provided at a connection portion between the upstream side of the bypass passage 14 and the coolant circulation circuit 11.

切替バルブ１５は、図２（ａ），（ｂ）に示すように、軸方向に貫通する中空部を有するとともに側部に開口部５１が設けられた本体５０と、本体５０の中空部に摺動可能に挿入された筒状の弁体５２と、本体５０の一端部との間に流通口５４を形成する固定部５３と、一端を固定部５３に取り付けられるとともに他端を弁体５２に取り付けられたスプリング５５と、一端を弁体５２に固定されたピストン５６と、低温時に凝固して体積が縮小するとともに高温時に溶融して体積が膨張するワックスペレット５７と、ワックスペレット５７に取り付けられたヒータ５８とを有する。また、ヒータ５８の通電ＯＮ・ＯＦＦはＥＣＵ２０によって制御されている。   As shown in FIGS. 2A and 2B, the switching valve 15 includes a main body 50 having a hollow portion penetrating in the axial direction and provided with an opening 51 on a side portion thereof, and a slide on the hollow portion of the main body 50. A cylindrical valve body 52 that is movably inserted, a fixed portion 53 that forms a flow port 54 between one end of the main body 50, one end attached to the fixed portion 53, and the other end to the valve body 52. An attached spring 55, a piston 56 having one end fixed to the valve body 52, a wax pellet 57 that solidifies at a low temperature and shrinks in volume, melts at a high temperature and expands in volume, and is attached to the wax pellet 57. And a heater 58. The energization ON / OFF of the heater 58 is controlled by the ECU 20.

この切替バルブ１５では、ＥＣＵ２０からの信号によりヒータ５８の通電がＯＦＦに制御されると、ワックスペレット５７の体積は凝固により縮小する。そして、ワックスペレット５７の体積が縮小すると、弁体５２はスプリング５５の付勢力により移動して開口部５１を塞ぐように構成されている。すなわち、弁体５２が固定部５３から離間して流通口５４が開放されることで切替バルブ１５は開状態に維持される（図２（ａ）参照）。このように、切替バルブ１５が開状態に維持されると、サブラジエータ１２を通過した冷却水はインタークーラ１０へと供給され、インタークーラ１０を通過した後に再びサブラジエータ１２へと戻される。   In the switching valve 15, when the energization of the heater 58 is controlled to be turned off by a signal from the ECU 20, the volume of the wax pellet 57 is reduced by solidification. When the volume of the wax pellet 57 is reduced, the valve body 52 is configured to move by the urging force of the spring 55 so as to close the opening 51. That is, when the valve body 52 is separated from the fixed portion 53 and the flow port 54 is opened, the switching valve 15 is maintained in the open state (see FIG. 2A). In this way, when the switching valve 15 is maintained in the open state, the cooling water that has passed through the sub-radiator 12 is supplied to the intercooler 10, and after passing through the intercooler 10, is returned to the sub-radiator 12 again.

一方、ＥＣＵ２０からの信号によりヒータ５８の通電がＯＮに制御されると、ワックスペレット５７の体積は溶融により膨張する。そして、ワックスペレット５７の体積が膨張すると、弁体５２はスプリング５５の付勢力に抗して移動して開口部５１を開放するように構成されている。すなわち、弁体５２が固定部５３に当接して流通口５４が塞がれるとともに、開口部５１が開放されることで切替バルブ１５は閉状態に維持される（図２（ｂ）参照）。このように、切替バルブ１５が閉状態に維持されると、サブラジエータ１２を通過した冷却水はインタークーラ１０を迂回してバイパス通路１４へと流され、バイパス通路１４を通過した後に再びサブラジエータ１２へと戻される。   On the other hand, when energization of the heater 58 is controlled to be ON by a signal from the ECU 20, the volume of the wax pellet 57 expands due to melting. And when the volume of the wax pellet 57 expands, the valve body 52 moves against the urging force of the spring 55 to open the opening 51. That is, the valve body 52 contacts the fixed portion 53 to close the flow port 54, and the opening portion 51 is opened, whereby the switching valve 15 is maintained in the closed state (see FIG. 2B). In this way, when the switching valve 15 is maintained in the closed state, the cooling water that has passed through the sub-radiator 12 bypasses the intercooler 10 and flows to the bypass passage 14, and after passing through the bypass passage 14, the sub-radiator again. 12 is returned.

第１吸気温センサ１６は、図１に示すように、インタークーラ１０よりも上流側に位置する低圧段出口吸気通路３９に設けられている。また、第１吸気温センサ１６は電気配線を介してＥＣＵ２０に接続されている。すなわち、第１吸気温センサ１６は、低圧段コンプレッサ３３ａにより圧縮された低圧吸気の温度を検出してＥＣＵ２０に出力するように構成されている。   As shown in FIG. 1, the first intake air temperature sensor 16 is provided in the low-pressure stage outlet intake passage 39 that is located upstream of the intercooler 10. Further, the first intake air temperature sensor 16 is connected to the ECU 20 via an electrical wiring. That is, the first intake air temperature sensor 16 is configured to detect the temperature of the low-pressure intake air compressed by the low-pressure compressor 33a and output it to the ECU 20.

第２吸気温センサ１７は、図１に示すように、インタークーラ１０よりも下流側に位置する低圧段出口吸気通路３９に設けられている。また、第２吸気温センサ１７は電気配線を介してＥＣＵ２０に接続されている。すなわち、第２吸気温センサ１７は、インタークーラ１０を通過した低圧吸気の温度を検出してＥＣＵ２０に出力するように構成されている。   As shown in FIG. 1, the second intake air temperature sensor 17 is provided in the low-pressure stage outlet intake passage 39 located on the downstream side of the intercooler 10. Further, the second intake air temperature sensor 17 is connected to the ECU 20 via an electrical wiring. That is, the second intake air temperature sensor 17 is configured to detect the temperature of the low-pressure intake air that has passed through the intercooler 10 and output it to the ECU 20.

ＥＣＵ２０は、エンジン３１の運転状態に応じて燃料噴射期間や燃料噴射量等の各種制御を行うもので、公知のＣＰＵやＲＯＭ、ＲＡＭ、入力ポート、出力ポート等を備え構成されている。この各種制御を行うために、ＥＣＵ２０には、アクセルセンサ（不図示）、エンジン回転数センサ（不図示）、第１吸気温センサ１６、第２吸気温センサ１７等の各種センサの出力信号がＡ／Ｄ変換された後に入力される。   The ECU 20 performs various controls such as a fuel injection period and a fuel injection amount according to the operating state of the engine 31, and includes a known CPU, ROM, RAM, input port, output port, and the like. In order to perform the various controls, the ECU 20 receives output signals from various sensors such as an accelerator sensor (not shown), an engine speed sensor (not shown), the first intake air temperature sensor 16 and the second intake air temperature sensor 17. Input after / D conversion.

また、ＥＣＵ２０は、冷却判定部２１と切替バルブ制御部２２とを一部の機能要素として有する。これら各機能要素は、本実施形態では一体のハードウェアであるＥＣＵ２０に含まれるものとして説明するが、これらのいずれか一部を別体のハードウェアに設けることもできる。   Further, the ECU 20 includes a cooling determination unit 21 and a switching valve control unit 22 as a part of functional elements. In the present embodiment, these functional elements are described as being included in the ECU 20 that is an integral hardware, but any one of these functional elements may be provided in separate hardware.

冷却判定部２１は、第１吸気温センサ１６により検出されたインタークーラ１０よりも上流側を流れる低圧吸気の温度（以下、流入吸気温度ＴＡINという）と、第２吸気温センサ１７により検出されたインタークーラ１０よりも下流側を流れる低圧吸気の温度（以下、流出吸気温度ＴＡOUTという）とに基づいて、インタークーラ１０を通過する低圧吸気が冷却水との熱交換により冷却されるか否かを判定する。具体的には、流出吸気温度ＴＡOUTが流入吸気温度ＴＡINよりも小さい場合（ＴＡOUT＜ＴＡIN）は、低圧吸気が冷却水との熱交換により冷却されると判定する。一方、流出吸気温度ＴＡOUTが流入吸気温度ＴＡIN以上の場合（ＴＡOUT≧ＴＡIN）は、低圧吸気が冷却水との熱交換により冷却されないと判定する。 The cooling determination unit 21 is detected by the temperature of the low-pressure intake air flowing upstream of the intercooler 10 detected by the first intake air temperature sensor 16 (hereinafter referred to as inflow intake air temperature TA IN ) and the second intake air temperature sensor 17. Whether or not the low-pressure intake air passing through the intercooler 10 is cooled by heat exchange with the cooling water based on the temperature of the low-pressure intake air flowing downstream from the intercooler 10 (hereinafter referred to as the outflow intake air temperature TA OUT ). Determine whether. Specifically, when the outflow intake air temperature TA OUT is smaller than the inflow intake air temperature TA IN (TA OUT <TA IN ), it is determined that the low pressure intake air is cooled by heat exchange with the cooling water. On the other hand, when the outflow intake air temperature TA OUT is equal to or higher than the inflow intake air temperature TA IN (TA OUT ≧ TA IN ), it is determined that the low pressure intake air is not cooled by heat exchange with the cooling water.

切替バルブ制御部２２は、冷却判定部２１の判定結果に応じて切替バルブ１５の開閉を制御する。具体的には、低圧吸気が冷却水との熱交換により冷却されると判定された場合（ＴＡOUT＜ＴＡIN）は、冷却水循環回路１１を流れる冷却水をインタークーラ１０に流すべく、切替バルブ１５を開状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＦＦにする制御信号を出力する。 The switching valve control unit 22 controls opening / closing of the switching valve 15 according to the determination result of the cooling determination unit 21. Specifically, when it is determined that the low-pressure intake air is cooled by heat exchange with the cooling water (TA OUT <TA IN ), the switching valve is used to flow the cooling water flowing through the cooling water circulation circuit 11 to the intercooler 10. 15 is controlled to an open state. That is, a control signal for turning off the energization of the heater 58 of the switching valve 15 is output.

一方、低圧吸気が冷却水との熱交換により冷却されないと判定された場合（ＴＡOUT≧ＴＡIN）は、冷却水循環回路１１を流れる冷却水をバイパス通路１４に流すべく、切替バルブ１５を閉状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＮにする制御信号を出力する。 On the other hand, when it is determined that the low-pressure intake air is not cooled by heat exchange with the cooling water (TA OUT ≧ TA IN ), the switching valve 15 is closed so that the cooling water flowing through the cooling water circulation circuit 11 flows to the bypass passage 14. To control. That is, a control signal for turning on the heater 58 of the switching valve 15 is output.

また、切替バルブ制御部２２は、第１吸気温センサ１６の検出値（流入吸気温度ＴIN）が上限閾値ＴMAXよりも大きい場合は、流入吸気温度ＴＡINと流出吸気温度ＴＡOUTとの関係にかかわらず冷却水をインタークーラ１０に流す制御信号を出力する（ヒータ５８の通電をＯＦＦ）。この上限閾値ＴMAXは実験等でＥＣＵ２０に予め記憶された温度で、エンジン３１の運転状態が高負荷運転の時に冷却水循環回路１１を流れる冷却水が昇温される最高温度に設定されている。 Further, when the detected value (inflow intake air temperature T IN ) of the first intake air temperature sensor 16 is larger than the upper limit threshold T MAX , the switching valve control unit 22 relates the inflow intake air temperature TA IN and the outflow intake air temperature TA OUT. Regardless of this, a control signal for flowing cooling water to the intercooler 10 is output (energization of the heater 58 is turned off). The upper limit threshold T MAX is a temperature stored in advance in the ECU 20 through experiments or the like, and is set to a maximum temperature at which the cooling water flowing through the cooling water circulation circuit 11 is heated when the operation state of the engine 31 is a high load operation.

本発明の第一実施形態に係る吸気冷却装置１は、以上のように構成されているので、例えば図３に示すフローに従って以下のような制御が行われる。   Since the intake air cooling device 1 according to the first embodiment of the present invention is configured as described above, for example, the following control is performed according to the flow shown in FIG.

ステップ（以下、ステップを単にＳと記載する）１００では、ヒータ５８の通電状態（ＯＮ・ＯＦＦ）に基づいて、切替バルブ１５の開閉判定が行われる。切替バルブ制御部２２によりヒータ５８の通電がＯＦＦに制御されている場合は、切替バルブ１５は開状態（冷却水の流路はインタークーラ１０）と判定されてＳ１１０へと進む。一方、切替バルブ制御部２２により、ヒータ５８の通電がＯＮに制御されている場合は、切替バルブ１５は閉状態（冷却水の流路はバイパス通路１４）と判定されてＳ１４０へと進む。   In step (hereinafter, “step” is simply referred to as S) 100, open / close determination of the switching valve 15 is performed based on the energization state (ON / OFF) of the heater 58. When the energization of the heater 58 is controlled to be OFF by the switching valve control unit 22, the switching valve 15 is determined to be in the open state (the cooling water flow path is the intercooler 10), and the process proceeds to S110. On the other hand, when the energization of the heater 58 is controlled to be ON by the switching valve control unit 22, the switching valve 15 is determined to be closed (the cooling water flow path is the bypass passage 14), and the process proceeds to S140.

Ｓ１１０では、冷却判定部２１により、インタークーラを通過する低圧吸気が冷却水で冷却されるか否かが判定される。流出吸気温度ＴＡOUTが流入吸気温度ＴＡINよりも小さい場合（ＴＡOUT＜ＴＡIN）は、低圧吸気は冷却されると判定されてＳ１２０へと進む。一方、流出吸気温度ＴＡOUTが流入吸気温度ＴＡIN以上の場合（ＴＡOUT≧ＴＡIN）は、低圧吸気は冷却されないと判定されてＳ１３０へと進む。 In S110, the cooling determination unit 21 determines whether or not the low-pressure intake air that passes through the intercooler is cooled by the cooling water. When the outflow intake air temperature TA OUT is smaller than the inflow intake air temperature TA IN (TA OUT <TA IN ), it is determined that the low pressure intake air is cooled, and the process proceeds to S120. On the other hand, when the outflow intake air temperature TA OUT is equal to or higher than the inflow intake air temperature TA IN (TA OUT ≧ TA IN ), it is determined that the low pressure intake air is not cooled, and the process proceeds to S130.

Ｓ１２０では、Ｓ１１０で低圧吸気が冷却されると判定されたことを受けて、ヒータ５８の通電をＯＦＦにする制御信号が維持される。すなわち、切替バルブ１５は開状態に維持されるとともに、冷却水の流路はインタークーラ１０に維持されて本制御はリターンされる。   In S120, in response to the determination that the low-pressure intake air is cooled in S110, the control signal for turning off the heater 58 is maintained. That is, the switching valve 15 is maintained in the open state, the flow path of the cooling water is maintained in the intercooler 10, and this control is returned.

一方、Ｓ１１０で低圧吸気が冷却さないと判定された場合は、Ｓ１３０で、ヒータ５８の通電をＯＮにする制御信号が切替バルブ制御部２２から出力される。すなわち、切替バルブ１５が閉状態に制御され、冷却水の流路はバイパス通路１４に切替えられて本制御はリターンされる。   On the other hand, if it is determined in S110 that the low-pressure intake air is not cooled, a control signal for turning on the heater 58 is output from the switching valve control unit 22 in S130. That is, the switching valve 15 is controlled to be closed, the flow path of the cooling water is switched to the bypass passage 14, and this control is returned.

Ｓ１００で、切替バルブ１５が閉状態（冷却水の流路はバイパス通路１４）と判定された場合は、Ｓ１４０で流入吸気温度ＴＡINが上限閾値ＴMAXを超えたか否かが確認される。流入吸気温度ＴＡINが上限閾値ＴMAXを超えている場合は、冷却水温が低圧吸気温よりも低いことが予測されるので、冷却水をインタークーラ１０に流すべく、Ｓ１５０でヒータ５８の通電をＯＦＦにする制御信号が切替バルブ制御部２２から出力される。一方、流入吸気温度ＴＡINが上限閾値ＴMAX以下の場合は、冷却水温が低圧吸気温よりも高い場合もあるので、切替バルブ１５を閉状態に維持して本制御はリターンされる。 In S100, the switching valve 15 when it is determined that the closed state (the flow path of the cooling water bypass passage 14), the inflow air temperature TA IN in S140 whether exceeds the upper threshold value T MAX is confirmed. If the inflow intake air temperature TA IN exceeds the upper limit threshold value T MAX , it is predicted that the cooling water temperature is lower than the low pressure intake air temperature, so that the heater 58 is energized in S150 so that the cooling water flows to the intercooler 10. A control signal for turning OFF is output from the switching valve control unit 22. On the other hand, if the inlet air temperature TA IN is less than the upper limit threshold value T MAX is the cooling water temperature is also higher than the low pressure intake air temperature, the control maintains the switching valve 15 in the closed state is returned.

以上のような構成により、本発明の第一実施形態に係る吸気冷却装置１によれば以下のような作用効果を奏する。   With the configuration as described above, the intake air cooling device 1 according to the first embodiment of the present invention has the following operational effects.

インタークーラ１０を通過した低圧段出口吸気の温度（流出吸気温度ＴＡOUT）が、インタークーラ１０に流入する低圧段出口吸気の温度（流入吸気温度ＴＡIN）よりも小さい場合（ＴＡOUT＜ＴＡIN）は、低圧段出口吸気が冷却水との熱交換により冷却される。このように、低圧段出口吸気が冷却される場合、切替バルブ１５は開状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からインタークーラ１０を通過してサブラジエータ１２へと戻される。 When the temperature of the low-pressure stage outlet intake air that has passed through the intercooler 10 (outflow intake air temperature TA OUT ) is smaller than the temperature of the low-pressure stage outlet intake air that flows into the intercooler 10 (inflow intake air temperature TA IN ) (TA OUT <TA IN). ), The low-pressure stage outlet intake air is cooled by heat exchange with the cooling water. As described above, when the low-pressure stage outlet intake air is cooled, the switching valve 15 is controlled to be in an open state, and the flow path of the cooling water flowing through the cooling water circulation circuit 11 passes from the sub radiator 12 to the inter cooler 10 and passes through the sub radiator 12. Returned to.

一方、インタークーラ１０を通過した低圧段出口吸気の温度（流出吸気温度ＴＡOUT）が、インタークーラ１０に流入する低圧吸気の温度（流入吸気温度ＴＡIN）以上の場合（ＴＡOUT≧ＴＡIN）は、低圧吸気が冷却水との熱交換により冷却されずに昇温される。このように、低圧段出口吸気が冷却されない場合、切替バルブ１５は閉状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からバイパス通路１４を通過（インタークーラ１０を迂回）してサブラジエータ１２へと戻される。 On the other hand, when the temperature of the low pressure stage outlet intake air that has passed through the intercooler 10 (outflow intake air temperature TA OUT ) is equal to or higher than the temperature of the low pressure intake air flowing into the intercooler 10 (inflow intake air temperature TA IN ) (TA OUT ≧ TA IN ). The low-pressure intake air is heated without being cooled by heat exchange with the cooling water. Thus, when the low-pressure stage outlet intake air is not cooled, the switching valve 15 is controlled to be closed, and the flow path of the coolant flowing through the coolant circulation circuit 11 passes from the sub radiator 12 through the bypass passage 14 (bypassing the intercooler 10). ) And returned to the sub-radiator 12.

したがって、エンジン３１の部分負荷運転時など冷却水の温度が高い場合に、低圧段コンプレッサ３３ａで圧縮された低圧段出口吸気が冷却水によって昇温されることを効果的に抑制することができるので、エンジン３１の運転領域全域で二段過給システム３０の効率を維持できるとともに、エンジン３１の燃費悪化も効果的に抑止することができる。   Therefore, when the temperature of the cooling water is high, such as during partial load operation of the engine 31, it is possible to effectively suppress the low-pressure stage outlet intake air compressed by the low-pressure stage compressor 33a from being heated by the cooling water. In addition, the efficiency of the two-stage turbocharging system 30 can be maintained over the entire operation region of the engine 31, and the fuel consumption deterioration of the engine 31 can be effectively suppressed.

＜第二実施形態＞
以下、図４，５に基づいて、本発明の第二実施形態について説明する。 <Second embodiment>
The second embodiment of the present invention will be described below based on FIGS.

図４に示すように、本発明の第二実施形態に係る吸気冷却装置２は、上述の第一実施形態における第１吸気温センサ１６を、インタークーラ１０よりも上流側の冷却水循環回路１１を流れる冷却水の温度を検出する第１冷却水温センサ（第３温度検出手段）１８に置き換え、かつ、第２吸気温センサ１７を、インタークーラ１０よりも下流側の冷却水循環回路１１を流れる冷却水の温度を検出する第２冷却水温センサ（第４温度検出手段）１９に置き換えたものである。したがって、その他の構成は第一実施形態の吸気冷却装置１と同様であるので、ここでは他の構成についての詳細な説明を省略する。   As shown in FIG. 4, the intake air cooling device 2 according to the second embodiment of the present invention uses the first intake air temperature sensor 16 in the first embodiment described above as the cooling water circulation circuit 11 upstream of the intercooler 10. The first cooling water temperature sensor (third temperature detection means) 18 that detects the temperature of the flowing cooling water is replaced, and the second intake air temperature sensor 17 is the cooling water that flows through the cooling water circulation circuit 11 on the downstream side of the intercooler 10. This is replaced with a second cooling water temperature sensor (fourth temperature detecting means) 19 for detecting the temperature of the first cooling water. Therefore, since the other structure is the same as that of the intake air cooling device 1 of the first embodiment, a detailed description of the other structure is omitted here.

第１冷却水温センサ１８は、図４に示すように、インタークーラ１０よりも上流側に位置する冷却水循環回路１１に設けられている。また、第１冷却水温センサ１８は電気配線を介してＥＣＵ２０に接続されている。すなわち、第１冷却水温センサ１８は、サブラジエータ１２で外気との熱交換により冷却された冷却水の温度を検出してＥＣＵ２０に出力するように構成されている。   As shown in FIG. 4, the first coolant temperature sensor 18 is provided in the coolant circulation circuit 11 located on the upstream side of the intercooler 10. Moreover, the 1st cooling water temperature sensor 18 is connected to ECU20 via the electrical wiring. That is, the first cooling water temperature sensor 18 is configured to detect the temperature of the cooling water cooled by heat exchange with the outside air by the sub radiator 12 and output the detected temperature to the ECU 20.

第２冷却水温センサ１９は、図４に示すように、サブラジエータ１２よりも下流側に位置する冷却水循環回路１１に設けられている。また、第２冷却水温センサ１９は電気配線を介してＥＣＵ２０に接続されている。すなわち、第２冷却水温センサ１９は、インタークーラ１０を通過した冷却水の温度を検出してＥＣＵ２０に出力するように構成されている。   As shown in FIG. 4, the second coolant temperature sensor 19 is provided in the coolant circulation circuit 11 located on the downstream side of the sub radiator 12. Moreover, the 2nd cooling water temperature sensor 19 is connected to ECU20 via the electrical wiring. That is, the second cooling water temperature sensor 19 is configured to detect the temperature of the cooling water that has passed through the intercooler 10 and output the detected temperature to the ECU 20.

冷却判定部２１は、第１冷却水温センサ１８により検出されたインタークーラ１０よりも上流側を流れる冷却水の温度（以下、流入冷却水温度ＴＷINという）と、第２冷却水温センサ１９により検出されたインタークーラ１０よりも下流側を流れる冷却水の温度（以下、流出冷却水温度ＴＷOUTという）とに基づいて、インタークーラ１０を通過する低圧段出口吸気が冷却水との熱交換により冷却されるか否かを判定する。具体的には、流入冷却水温度ＴＷINが流出冷却水温度ＴＷOUTよりも小さい場合（ＴＷIN＜ＴＷOUT）は、低圧段出口吸気が冷却水との熱交換により冷却されると判定する。一方、流入冷却水温度ＴＷINが流出冷却水温度ＴＷOUT以上の場合（ＴＷIN≧ＴＷOUT）は、低圧段出口吸気が冷却水との熱交換により冷却されないと判定する。 Cooling determination unit 21, the temperature of the cooling water flowing through the upstream side of the intercooler 10 detected by the first cooling water temperature sensor 18 (hereinafter, referred to as inlet coolant temperature TW IN) and, detected by the second coolant temperature sensor 19 The low-pressure stage outlet intake air passing through the intercooler 10 is cooled by heat exchange with the cooling water based on the temperature of the cooling water flowing downstream from the intercooler 10 (hereinafter referred to as the outflow cooling water temperature TW OUT ). It is determined whether or not. Specifically, when the inflow cooling water temperature TW IN is smaller than the outflow cooling water temperature TW OUT (TW IN <TW OUT ), it is determined that the low-pressure stage outlet intake air is cooled by heat exchange with the cooling water. On the other hand, when the inflow cooling water temperature TW IN is equal to or higher than the outflow cooling water temperature TW OUT (TW IN ≧ TW OUT ), it is determined that the low-pressure stage outlet intake air is not cooled by heat exchange with the cooling water.

切替バルブ制御部２２は、冷却判定部２１の判定結果に応じて切替バルブ１５の開閉を制御する。具体的には、低圧段出口吸気が冷却水との熱交換により冷却されると判定された場合（ＴＷIN＜ＴＷOUT）は、冷却水循環回路１１を流れる冷却水をインタークーラ１０に流すべく、切替バルブ１５を開状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＦＦにする制御信号を出力する。 The switching valve control unit 22 controls opening / closing of the switching valve 15 according to the determination result of the cooling determination unit 21. Specifically, when it is determined that the low-pressure stage outlet intake air is cooled by heat exchange with the cooling water (TW IN <TW OUT ), in order to flow the cooling water flowing through the cooling water circulation circuit 11 to the intercooler 10, The switching valve 15 is controlled to be opened. That is, a control signal for turning off the energization of the heater 58 of the switching valve 15 is output.

一方、低圧段出口吸気が冷却水との熱交換により冷却されないと判定された場合（ＴＷIN≧ＴＷOUT）は、冷却水循環回路１１を流れる冷却水をバイパス通路１４に流すべく、切替バルブ１５を閉状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＮにする制御信号を出力する。 On the other hand, when it is determined that the low-pressure stage outlet intake air is not cooled by heat exchange with the cooling water (TW IN ≧ TW OUT ), the switching valve 15 is set to flow the cooling water flowing through the cooling water circulation circuit 11 to the bypass passage 14. Control to the closed state. That is, a control signal for turning on the heater 58 of the switching valve 15 is output.

また、切替バルブ制御部２２は、第１冷却水温センサ１８の検出値（流入冷却水温度ＴＷIN）が下限閾値ＴMINよりも小さい場合は、流入冷却水温度ＴＷINと流出冷却水温度ＴＷOUTとの関係にかかわらず冷却水をインタークーラ１０に流す制御信号を出力する（ヒータ５８の通電をＯＦＦ）。この下限閾値ＴMINは実験等でＥＣＵ２０に予め記憶された温度で、エンジン３１の運転状態に応じて低圧段コンプレッサ３３ａで圧縮される低圧段出口吸気の最低温度に設定されている。 In addition, when the detected value (inflow cooling water temperature TW IN ) of the first cooling water temperature sensor 18 is smaller than the lower limit threshold value T MIN , the switching valve control unit 22 determines the inflow cooling water temperature TW IN and the outflow cooling water temperature TW OUT. Regardless of the relationship, a control signal for flowing cooling water to the intercooler 10 is output (energization of the heater 58 is OFF). This lower limit threshold T MIN is a temperature stored in advance in the ECU 20 through experiments or the like, and is set to the lowest temperature of the low-pressure stage outlet intake air that is compressed by the low-pressure stage compressor 33a in accordance with the operating state of the engine 31.

本発明の第二実施形態に係る吸気冷却装置２は、以上のように構成されているので、例えば図５に示すフローに従って以下のような制御が行われる。   Since the intake air cooling device 2 according to the second embodiment of the present invention is configured as described above, for example, the following control is performed according to the flow shown in FIG.

Ｓ２００では、ヒータ５８の通電状態（ＯＮ・ＯＦＦ）に基づいて、切替バルブ１５の開閉判定が行われる。切替バルブ制御部２２によりヒータ５８の通電がＯＦＦに制御されている場合は、切替バルブ１５は開状態（冷却水の流路はインタークーラ１０）と判定されてＳ２１０へと進む。一方、切替バルブ制御部２２により、ヒータ５８の通電がＯＮに制御されている場合は、切替バルブ１５は閉状態（冷却水の流路はバイパス通路１４）と判定されてＳ２４０へと進む。   In S200, open / close determination of the switching valve 15 is performed based on the energized state (ON / OFF) of the heater 58. When the switching valve control unit 22 controls the energization of the heater 58 to be OFF, the switching valve 15 is determined to be in the open state (the cooling water flow path is the intercooler 10), and the process proceeds to S210. On the other hand, when the energization of the heater 58 is controlled to be ON by the switching valve control unit 22, the switching valve 15 is determined to be closed (the cooling water flow path is the bypass passage 14), and the process proceeds to S240.

Ｓ２１０では、冷却判定部２１により、インタークーラを通過する低圧段出口吸気が冷却水で冷却されるか否かが判定される。流入冷却水温度ＴＷINが流出冷却水温度ＴＷOUTよりも小さい場合（ＴＷIN＜ＴＷOUT）は、低圧段出口吸気は冷却されると判定されてＳ２２０へと進む。一方、流入冷却水温度ＴＷINが流出冷却水温度ＴＷOUT以上の場合（ＴＷIN≧ＴＷOUT）は、低圧段出口吸気は冷却されないと判定されてＳ２３０へと進む。 In S210, the cooling determination unit 21 determines whether or not the low-pressure stage outlet intake air that passes through the intercooler is cooled by the cooling water. When the inflow cooling water temperature TW IN is smaller than the outflow cooling water temperature TW OUT (TW IN <TW OUT ), it is determined that the low pressure stage outlet intake air is cooled, and the process proceeds to S220. On the other hand, when the inflow cooling water temperature TW IN is equal to or higher than the outflow cooling water temperature TW OUT (TW IN ≧ TW OUT ), it is determined that the low-pressure stage outlet intake air is not cooled, and the process proceeds to S230.

Ｓ２２０では、Ｓ２１０で低圧段出口吸気が冷却されると判定されたことを受けて、ヒータ５８の通電をＯＦＦにする制御信号が維持される。すなわち、切替バルブ１５は開状態に維持されるとともに、冷却水の流路はインタークーラ１０に維持されて本制御はリターンされる。   In S220, in response to the determination that the low-pressure stage outlet intake air is cooled in S210, the control signal for turning off the heater 58 is maintained. That is, the switching valve 15 is maintained in the open state, the flow path of the cooling water is maintained in the intercooler 10, and this control is returned.

一方、Ｓ２１０で低圧段出口吸気が冷却さないと判定された場合は、Ｓ２３０で、ヒータ５８の通電をＯＮにする制御信号が切替バルブ制御部２２から出力される。すなわち、切替バルブ１５が閉状態に制御され、冷却水の流路はバイパス通路１４に切替えられて本制御はリターンされる。   On the other hand, when it is determined in S210 that the low-pressure stage outlet intake air is not cooled, a control signal for turning on the heater 58 is output from the switching valve control unit 22 in S230. That is, the switching valve 15 is controlled to be closed, the flow path of the cooling water is switched to the bypass passage 14, and this control is returned.

Ｓ２００で、切替バルブ１５が閉状態（冷却水の流路はバイパス通路１４）と判定された場合は、Ｓ２４０で流入冷却水温度ＴＷINが下限閾値ＴMINより小さいか否かが確認される。流入冷却水温度ＴＷINが下限閾値ＴMINより小さい場合は、冷却水温が低圧段出口吸気温よりも十分に低いことが予測されるので、冷却水をインタークーラ１０に流すべく、Ｓ２５０でヒータ５８の通電をＯＦＦにする制御信号が切替バルブ制御部２２から出力される。一方、流入冷却水温度ＴＷINが下限閾値ＴMIN以上の場合は、冷却水温が低圧段出口吸気温よりも高い場合もあるので、切替バルブ１５を閉状態に維持して本制御はリターンされる。 In S200, the switching valve 15 when it is determined that the closed state (the cooling water flow path bypass passage 14), the inflow coolant temperature TW IN is whether the lower limit threshold T MIN is less than or is confirmed by S240. If the inflow coolant temperature TW IN is smaller than the lower limit threshold value T MIN is the cooling water temperature is sufficiently low is expected than the low-pressure stage outlet intake temperature, to flow the cooling water in the intercooler 10, the heater 58 in S250 The switching valve control unit 22 outputs a control signal for turning off energization. On the other hand, if the inlet cooling water temperature TW IN is equal to or higher than the lower threshold T MIN is the cooling water temperature is also higher than the low-pressure stage outlet intake temperature, the control maintains the switching valve 15 in the closed state is returned .

以上のような構成により、本発明の第二実施形態に係る吸気冷却装置２によれば以下のような作用効果を奏する。   With the configuration as described above, the intake air cooling device 2 according to the second embodiment of the present invention has the following operational effects.

インタークーラ１０よりも上流側を流れる冷却水の温度（流入吸気温度ＴＷIN）が、インタークーラ１０よりも下流側を流れる冷却水の温度（流出吸気温度ＴＷOUT）よりも小さい場合（ＴＷIN＜ＴＷOUT）は、低圧段出口吸気が冷却水との熱交換により冷却される。このように、低圧段出口吸気が冷却される場合、切替バルブ１５は開状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からインタークーラ１０を通過してサブラジエータ１２へと戻される。 When the temperature of the coolant flowing upstream from the intercooler 10 (inflow intake air temperature TW IN ) is smaller than the temperature of the coolant flowing downstream from the intercooler 10 (outflow intake air temperature TW OUT ) (TW IN < TW OUT ) is cooled by heat exchange between the low-pressure stage outlet intake air and the cooling water. As described above, when the low-pressure stage outlet intake air is cooled, the switching valve 15 is controlled to be in an open state, and the flow path of the cooling water flowing through the cooling water circulation circuit 11 passes from the sub radiator 12 to the inter cooler 10 and passes through the sub radiator 12. Returned to.

一方、インタークーラ１０よりも上流側を流れる冷却水の温度（流入吸気温度ＴＷIN）が、インタークーラ１０よりも下流側を流れる冷却水の温度（流出吸気温度ＴＷOUT）以上の場合（ＴＷIN≧ＴＷOUT）は、低圧段出口吸気が冷却水との熱交換により冷却されずに昇温される。このように、低圧段出口吸気が冷却されない場合、切替バルブ１５は閉状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からバイパス通路１４を通過（インタークーラ１０を迂回）してサブラジエータ１２へと戻される。 On the other hand, when the temperature of the cooling water flowing upstream from the intercooler 10 (inflow intake air temperature TW IN ) is equal to or higher than the temperature of cooling water flowing downstream from the intercooler 10 (outflow intake air temperature TW OUT ) (TW IN). ≧ TW OUT ), the low-pressure stage outlet intake air is heated without being cooled by heat exchange with the cooling water. Thus, when the low-pressure stage outlet intake air is not cooled, the switching valve 15 is controlled to be closed, and the flow path of the coolant flowing through the coolant circulation circuit 11 passes from the sub radiator 12 through the bypass passage 14 (bypassing the intercooler 10). ) And returned to the sub-radiator 12.

したがって、エンジン３１の部分負荷運転時など冷却水の温度が高い場合に、低圧段コンプレッサ３３ａで圧縮された低圧段出口吸気が冷却水によって昇温されることを効果的に抑制することができるので、エンジン３１の運転領域全域で二段過給システム３０の効率を維持できるとともに、エンジン３１の燃費悪化も効果的に抑止することができる。   Therefore, when the temperature of the cooling water is high, such as during partial load operation of the engine 31, it is possible to effectively suppress the low-pressure stage outlet intake air compressed by the low-pressure stage compressor 33a from being heated by the cooling water. In addition, the efficiency of the two-stage turbocharging system 30 can be maintained over the entire operation region of the engine 31, and the fuel consumption deterioration of the engine 31 can be effectively suppressed.

＜第三実施形態＞
以下、図６，７に基づいて、本発明の第三実施形態について説明する。 <Third embodiment>
The third embodiment of the present invention will be described below based on FIGS.

図６に示すように、本発明の第三実施形態に係る吸気冷却装置３は、上述の第一実施形態における第２吸気温センサ１７を、第二実施形態の第１冷却水温センサ１８に置き換えたものである。したがって、その他の構成は第一実施形態の吸気冷却装置１と同様であるので、ここでは他の構成についての詳細な説明を省略する。   As shown in FIG. 6, in the intake air cooling device 3 according to the third embodiment of the present invention, the second intake air temperature sensor 17 in the first embodiment is replaced with the first cooling water temperature sensor 18 in the second embodiment. It is a thing. Therefore, since the other structure is the same as that of the intake air cooling device 1 of the first embodiment, a detailed description of the other structure is omitted here.

冷却判定部２１は、第１吸気温センサ１６により検出されたインタークーラ１０よりも上流側を流れる低圧段出口吸気の温度（流入吸気温度ＴＡIN）と、第１冷却水温センサ１８により検出されたインタークーラ１０よりも上流側を流れる冷却水の温度（流入冷却水温度ＴＷIN）とに基づいて、インタークーラ１０を通過する低圧段出口吸気が冷却水との熱交換により冷却されるか否かを判定する。具体的には、流入冷却水温度ＴＷINが流入吸気温度ＴＡINよりも小さい場合（ＴＷIN＜ＴＡIN）は、低圧段出口吸気が冷却水との熱交換により冷却されると判定する。一方、流入冷却水温度ＴＷINが流入吸気温度ＴＡIN以上の場合（ＴＷIN≧ＴＡIN）は、低圧段出口吸気が冷却水との熱交換により冷却されないと判定する。 The cooling determination unit 21 detects the temperature of the low-pressure stage outlet intake air (inflow intake air temperature TA IN ) flowing upstream from the intercooler 10 detected by the first intake air temperature sensor 16 and the first cooling water temperature sensor 18. Whether or not the low-pressure stage outlet intake air passing through the intercooler 10 is cooled by heat exchange with the cooling water based on the temperature of the cooling water flowing upstream from the intercooler 10 (inflow cooling water temperature TW IN ). Determine. Specifically, when the inflow coolant temperature TW IN is less than the inflow air temperature TA IN (TW IN <TA IN ) determines that the low-pressure stage outlet air is cooled by heat exchange with the cooling water. On the other hand, if the inlet cooling water temperature TW IN is equal to or higher than the inflow air temperature TA IN (TW IN ≧ TA IN ) determines that the low-pressure stage outlet air is not cooled by heat exchange with the cooling water.

切替バルブ制御部２２は、冷却判定部２１の判定結果に応じて切替バルブ１５の開閉を制御する。具体的には、低圧段出口吸気が冷却水との熱交換により冷却されると判定された場合（ＴＷIN＜ＴＡIN）は、冷却水循環回路１１を流れる冷却水をインタークーラ１０に流すべく、切替バルブ１５を開状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＦＦにする制御信号を出力する。 The switching valve control unit 22 controls opening / closing of the switching valve 15 according to the determination result of the cooling determination unit 21. Specifically, when it is determined that the low-pressure stage outlet intake air is cooled by heat exchange with the cooling water (TW IN <TA IN ), the cooling water flowing through the cooling water circulation circuit 11 is caused to flow to the intercooler 10. The switching valve 15 is controlled to be opened. That is, a control signal for turning off the energization of the heater 58 of the switching valve 15 is output.

一方、低圧吸気が冷却水との熱交換により冷却されないと判定された場合（ＴＷIN≧ＴＡIN）は、冷却水循環回路１１を流れる冷却水をバイパス通路１４に流すべく、切替バルブ１５を閉状態に制御する。すなわち、切替バルブ１５のヒータ５８の通電をＯＮにする制御信号を出力する。 On the other hand, when it is determined that the low-pressure intake air is not cooled by heat exchange with the cooling water (TW IN ≧ TA IN ), the switching valve 15 is closed so that the cooling water flowing through the cooling water circulation circuit 11 flows to the bypass passage 14. To control. That is, a control signal for turning on the heater 58 of the switching valve 15 is output.

本発明の第三実施形態に係る吸気冷却装置３は、以上のように構成されているので、例えば図７に示すフローに従って以下のような制御が行われる。   Since the intake air cooling device 3 according to the third embodiment of the present invention is configured as described above, for example, the following control is performed according to the flow shown in FIG.

Ｓ３００では、冷却判定部２１により、インタークーラ１０を通過する低圧段出口吸気が冷却水で冷却されるか否かが判定される。流入冷却水温度ＴＷINが流入吸気温度ＴＡINよりも小さい場合（ＴＷIN＜ＴＡIN）は、低圧段出口吸気は冷却されると判定されてＳ３１０へと進む。一方、流入冷却水温度ＴＷINが流入吸気温度ＴＡIN以上の場合（ＴＷIN≧ＴＡIN）は、低圧段出口吸気は冷却されないと判定されてＳ３２０へと進む。 In S300, the cooling determination unit 21 determines whether or not the low-pressure stage outlet intake air that passes through the intercooler 10 is cooled by the cooling water. If the inflow coolant temperature TW IN is less than the inflow air temperature TA IN (TW IN <TA IN ) is a low-pressure stage outlet air passes to S310 it is determined to be cooled. On the other hand, if the inlet cooling water temperature TW IN is equal to or higher than the inflow air temperature TA IN (TW IN ≧ TA IN ) is a low-pressure stage outlet air passes to S320 is judged not to be cooled.

Ｓ３１０では、Ｓ３００で低圧段出口吸気が冷却されると判定されたことを受けて、切替バルブ制御部２２からヒータ５８の通電をＯＦＦにする制御信号が出力される。すなわち、切替バルブ１５は開状態に制御されるとともに、冷却水の流路はインタークーラ１０に切替えられて本制御はリターンされる。   In S310, in response to the determination that the low pressure stage outlet intake air is cooled in S300, a control signal for turning off the heater 58 is output from the switching valve control unit 22. That is, the switching valve 15 is controlled to be in the open state, the flow path of the cooling water is switched to the intercooler 10, and this control is returned.

一方、Ｓ３００で低圧段出口吸気が冷却さないと判定された場合は、Ｓ３２０で、切替バルブ制御部２２からヒータ５８の通電をＯＮにする制御信号が出力される。すなわち、切替バルブ１５が閉状態に制御され、冷却水の流路はバイパス通路１４に切替えられて本制御はリターンされる。   On the other hand, when it is determined in S300 that the low-pressure stage outlet intake air is not cooled, a control signal for turning on the heater 58 is output from the switching valve control unit 22 in S320. That is, the switching valve 15 is controlled to be closed, the flow path of the cooling water is switched to the bypass passage 14, and this control is returned.

以上のような構成により、本発明の第三実施形態に係る吸気冷却装置３によれば以下のような作用効果を奏する。   With the configuration as described above, the intake air cooling device 3 according to the third embodiment of the present invention has the following operational effects.

インタークーラ１０よりも上流側を流れる冷却水の温度（流入冷却水温度ＴＷIN）が、インタークーラ１０よりも上流側を流れる低圧段出口吸気の温度（流入吸気温度ＴＡIN）よりも小さい場合（ＴＷIN＜ＴＡIN）は、低圧段出口吸気が冷却水との熱交換により冷却される。このように、低圧段出口吸気が冷却される場合、切替バルブ１５は開状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からインタークーラ１０を通過してサブラジエータ１２へと戻される。 When the temperature of the cooling water flowing upstream from the intercooler 10 (inflow cooling water temperature TW IN ) is lower than the temperature of the low-pressure stage outlet intake air flowing upstream from the intercooler 10 (inflow intake air temperature TA IN ) ( In TW IN <TA IN ), the low-pressure stage outlet intake air is cooled by heat exchange with the cooling water. As described above, when the low-pressure stage outlet intake air is cooled, the switching valve 15 is controlled to be in an open state, and the flow path of the cooling water flowing through the cooling water circulation circuit 11 passes from the sub radiator 12 to the inter cooler 10 and passes through the sub radiator 12. Returned to.

一方、インタークーラ１０よりも上流側を流れる冷却水の温度（流入冷却水温度ＴＷIN）が、インタークーラ１０よりも上流側を流れる低圧段出口吸気の温度（流入吸気温度ＴＡIN）以上の場合（ＴＷIN≧ＴＡIN）は、低圧段出口吸気が冷却水との熱交換により冷却されずに昇温される。このように、低圧段出口吸気が冷却されない場合、切替バルブ１５は閉状態に制御され、冷却水循環回路１１を流れる冷却水の流路はサブラジエータ１２からバイパス通路１４を通過（インタークーラ１０を迂回）してサブラジエータ１２へと戻される。 On the other hand, when the temperature of the cooling water flowing upstream from the intercooler 10 (inflow cooling water temperature TW IN ) is equal to or higher than the temperature of the low-pressure stage outlet intake air flowing upstream from the intercooler 10 (inflow intake air temperature TA IN ). (TW IN ≧ TA IN ) is raised without cooling the low-pressure stage outlet intake air by heat exchange with the cooling water. Thus, when the low-pressure stage outlet intake air is not cooled, the switching valve 15 is controlled to be closed, and the flow path of the coolant flowing through the coolant circulation circuit 11 passes from the sub radiator 12 through the bypass passage 14 (bypassing the intercooler 10). ) And returned to the sub-radiator 12.

したがって、エンジン３１の部分負荷運転時など冷却水の温度が高い場合に、低圧段コンプレッサ３３ａで圧縮された低圧段出口吸気が冷却水によって昇温されることを効果的に抑制することができるので、エンジン３１の運転領域全域で二段過給システム３０の総合効率低下を抑制できるとともに、エンジン３１の燃費悪化も効果的に抑止することができる。   Therefore, when the temperature of the cooling water is high, such as during partial load operation of the engine 31, it is possible to effectively suppress the low-pressure stage outlet intake air compressed by the low-pressure stage compressor 33a from being heated by the cooling water. In addition, the overall efficiency reduction of the two-stage turbocharging system 30 can be suppressed over the entire operation region of the engine 31, and the fuel consumption deterioration of the engine 31 can also be effectively suppressed.

なお、本発明は、上述の各実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲で、適宜変形して実施することが可能である。   The present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the spirit of the present invention.

例えば、上述の実施形態において、切替バルブ１５はワックスペレット５７により開閉されるものとして説明したが、電磁ソレノイドや油圧により作動するアクチュエータ等により開閉されるようにしてもよい。この場合も上述の各実施形態と同様の作用効果を奏することができる。   For example, although the switching valve 15 has been described as being opened and closed by the wax pellet 57 in the above-described embodiment, it may be opened and closed by an electromagnetic solenoid, an actuator that is operated by hydraulic pressure, or the like. In this case, the same effects as those of the above-described embodiments can be obtained.

また、インタークーラ１０に供給される冷却水はサブラジエータ１２で外気との熱交換により冷却されるものとして説明したが、例えば、エンジン３１のメインラジエータ（不図示）で冷却された冷却水を供給する構成としてもよい。この場合も上述の各実施形態と同様の作用効果を奏することができる。   Further, the cooling water supplied to the intercooler 10 has been described as being cooled by heat exchange with the outside air by the sub-radiator 12, but for example, cooling water cooled by a main radiator (not shown) of the engine 31 is supplied. It is good also as composition to do. In this case, the same effects as those of the above-described embodiments can be obtained.

１ 吸気冷却装置
１０ インタークーラ（吸気冷却手段）
１１ 冷却水循環回路
１２ サブラジエータ（冷却水冷却手段）
１４ バイパス通路
１５ 切替バルブ（流路切替手段）
１６ 吸気温センサ（第１温度検出手段）
１７ 第２吸気温センサ（第２温度検出手段）
２０ ＥＣＵ
３０ 二段過給システム
３１ エンジン
３２ 高圧段ターボチャージャ（高圧段過給機）
３３ 低圧段ターボチャージャ（低圧段過給機）
３９ 低圧段出口吸気通路 1 Intake air cooler 10 Intercooler (Intake air cooling means)
11 Cooling water circulation circuit 12 Sub-radiator (cooling water cooling means)
14 Bypass passage 15 Switching valve (Flow path switching means)
16 Intake air temperature sensor (first temperature detection means)
17 Second intake air temperature sensor (second temperature detecting means)
20 ECU
30 Two-stage turbocharging system 31 Engine 32 High-pressure turbocharger (high-pressure turbocharger)
33 Low-pressure turbocharger (low-pressure turbocharger)
39 Low pressure stage outlet intake passage

Claims (4)

内燃機関からの排気で駆動する高圧段過給機と低圧段過給機とを有する二段過給システムの吸気冷却装置であって、
前記低圧段過給機と前記高圧段過給機との間の吸気通路に設けられ、該吸気通路を流れる吸気を冷却水との熱交換により冷却する吸気冷却手段と、
前記冷却水を外気との熱交換により冷却する冷却水冷却手段と、
前記冷却水冷却手段を通過した冷却水を前記吸気冷却手段に供給するとともに前記冷却水冷却手段へと戻す冷却水循環回路と、
前記冷却水循環回路に設けられ、前記冷却水を前記吸気冷却手段からバイパスさせるバイパス通路と、
前記吸気が前記冷却水との熱交換により冷却されるか否かを判定する冷却判定手段と、 前記冷却判定手段の判定に応じて、前記吸気が前記冷却水により冷却されないと判定された場合は前記冷却水の流路を前記バイパス通路に切替え、かつ、前記吸気が前記冷却水により冷却されると判定された場合は前記冷却水の流路を前記吸気冷却手段に切替える流路切替手段とを有する
ことを特徴とする二段過給システムの吸気冷却装置。 An intake air cooling device for a two-stage supercharging system having a high-pressure stage supercharger and a low-pressure stage supercharger driven by exhaust from an internal combustion engine,
An intake air cooling means which is provided in an intake passage between the low pressure stage supercharger and the high pressure stage supercharger, and cools the intake air flowing through the intake passage by heat exchange with cooling water;
Cooling water cooling means for cooling the cooling water by heat exchange with outside air;
A cooling water circulation circuit that supplies the cooling water that has passed through the cooling water cooling means to the intake air cooling means and returns the cooling water to the cooling water cooling means;
A bypass passage provided in the cooling water circulation circuit for bypassing the cooling water from the intake air cooling means;
Cooling determination means for determining whether or not the intake air is cooled by heat exchange with the cooling water, and when it is determined that the intake air is not cooled by the cooling water according to the determination of the cooling determination means A flow path switching means for switching the flow path of the cooling water to the bypass passage and switching the flow path of the cooling water to the intake air cooling means when it is determined that the intake air is cooled by the cooling water. An intake air cooling device for a two-stage supercharging system. 前記冷却判定手段は、
前記吸気冷却手段よりも上流側に位置する前記吸気通路を流れる吸気温度を検出する第１温度検出手段と、前記吸気冷却手段よりも下流側に位置する前記吸気通路を流れる吸気温度を検出する第２温度検出手段とを有するとともに、
前記第２温度検出手段の検出値が前記第１温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第２温度検出手段の検出値が前記第１温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定する
ことを特徴とする請求項１記載の二段過給システムの吸気冷却装置。 The cooling determination means includes
A first temperature detecting means for detecting an intake air temperature flowing through the intake passage located upstream from the intake air cooling means; and a first temperature detecting means for detecting an intake air temperature flowing through the intake passage located downstream from the intake air cooling means. And 2 temperature detecting means,
When the detection value of the second temperature detection means is smaller than the detection value of the first temperature detection means, it is determined that the intake air is cooled by the cooling water, and the detection value of the second temperature detection means is 2. The intake air cooling device for a two-stage supercharging system according to claim 1, wherein the intake air is determined not to be cooled by the cooling water when the detected value is equal to or greater than a detection value of the first temperature detection means. 前記冷却判定手段は、
前記吸気冷却手段よりも上流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第３温度検出手段と、前記吸気冷却手段よりも下流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第４温度検出手段とを有するとともに、
前記第３温度検出手段の検出値が前記第４温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第３温度検出手段の検出値が前記第４温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定する
ことを特徴とする請求項１記載の二段過給システムの吸気冷却装置。 The cooling determination means includes
A third temperature detecting means for detecting a coolant temperature flowing through the cooling water circulation circuit located upstream from the intake air cooling means; and a coolant temperature flowing through the cooling water circulation circuit located downstream from the intake air cooling means. And a fourth temperature detecting means for detecting
When the detection value of the third temperature detection means is smaller than the detection value of the fourth temperature detection means, it is determined that the intake air is cooled by the cooling water, and the detection value of the third temperature detection means is 2. The intake air cooling device for a two-stage turbocharging system according to claim 1, wherein the intake air is determined not to be cooled by the cooling water when the detected value is equal to or greater than a detection value of the fourth temperature detection means. 前記冷却判定手段は、
前記吸気冷却手段よりも上流側に位置する前記冷却水循環回路を流れる冷却水温度を検出する第５温度検出手段と、前記吸気冷却手段よりも上流側に位置する前記吸気通路を流れる吸気温度を検出する第６温度検出手段とを有するとともに、
前記第５温度検出手段の検出値が前記第６温度検出手段の検出値よりも小さい場合は前記吸気が前記冷却水により冷却されると判定し、かつ、前記第５温度検出手段の検出値が前記第６温度検出手段の検出値以上の場合は前記吸気が前記冷却水により冷却されないと判定する
ことを特徴とする請求項１記載の二段過給システムの吸気冷却装置。 The cooling determination means includes
A fifth temperature detecting means for detecting a coolant temperature flowing through the cooling water circulation circuit located upstream from the intake air cooling means; and an intake air temperature flowing through the intake passage located upstream from the intake air cooling means. And a sixth temperature detecting means for
When the detection value of the fifth temperature detection means is smaller than the detection value of the sixth temperature detection means, it is determined that the intake air is cooled by the cooling water, and the detection value of the fifth temperature detection means is 2. The intake air cooling device for a two-stage supercharging system according to claim 1, wherein the intake air is determined not to be cooled by the cooling water when the detected value is equal to or greater than a detection value of the sixth temperature detection means.
JP2010236825A 2010-10-21 2010-10-21 Intake air cooling system for two-stage supercharging system Expired - Fee Related JP5614235B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2010236825A JP5614235B2 (en) 2010-10-21 2010-10-21 Intake air cooling system for two-stage supercharging system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2010236825A JP5614235B2 (en) 2010-10-21 2010-10-21 Intake air cooling system for two-stage supercharging system

Publications (2)

Publication Number Publication Date
JP2012087737A true JP2012087737A (en) 2012-05-10
JP5614235B2 JP5614235B2 (en) 2014-10-29

Family

ID=46259607

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2010236825A Expired - Fee Related JP5614235B2 (en) 2010-10-21 2010-10-21 Intake air cooling system for two-stage supercharging system

Country Status (1)

Country Link
JP (1) JP5614235B2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014119154A1 (en) 2013-01-29 2014-08-07 三菱重工業株式会社 Multi-stage supercharging system, and device and method for controlling same
EP3017161A1 (en) * 2013-07-04 2016-05-11 Valeo Systèmes Thermiques Device for regulating the circulation of a liquid coolant for a heat exchanger, particularly for a motor vehicle engine charge air cooler
WO2019102930A1 (en) * 2017-11-27 2019-05-31 株式会社ジャパンエンジンコーポレーション Marine diesel engine
KR20210143865A (en) * 2019-03-28 2021-11-29 에이비비 스위츠랜드 엘티디. Air supply apparatus for ships, ships comprising same, and method for supplying air to an air lubrication device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0479934U (en) * 1990-11-22 1992-07-13
US20080066697A1 (en) * 2006-09-20 2008-03-20 Man Nutzfahrzeuge Oesterreich Ag Cooling system of an internal combustion engine having charge air feed
JP2011503436A (en) * 2007-11-16 2011-01-27 スカニア シーブイ アクチボラグ Supercharged combustion engine configuration

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0479934U (en) * 1990-11-22 1992-07-13
US20080066697A1 (en) * 2006-09-20 2008-03-20 Man Nutzfahrzeuge Oesterreich Ag Cooling system of an internal combustion engine having charge air feed
JP2011503436A (en) * 2007-11-16 2011-01-27 スカニア シーブイ アクチボラグ Supercharged combustion engine configuration

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014119154A1 (en) 2013-01-29 2014-08-07 三菱重工業株式会社 Multi-stage supercharging system, and device and method for controlling same
US10557405B2 (en) 2013-01-29 2020-02-11 Mitsubishi Heavy Industries, Ltd. Multi-stage supercharging system and device and method for controlling the same
EP3017161A1 (en) * 2013-07-04 2016-05-11 Valeo Systèmes Thermiques Device for regulating the circulation of a liquid coolant for a heat exchanger, particularly for a motor vehicle engine charge air cooler
WO2019102930A1 (en) * 2017-11-27 2019-05-31 株式会社ジャパンエンジンコーポレーション Marine diesel engine
JP2019094874A (en) * 2017-11-27 2019-06-20 株式会社ジャパンエンジンコーポレーション Marine diesel engine
KR20210143865A (en) * 2019-03-28 2021-11-29 에이비비 스위츠랜드 엘티디. Air supply apparatus for ships, ships comprising same, and method for supplying air to an air lubrication device
KR102660673B1 (en) * 2019-03-28 2024-04-26 터보 시스템즈 스위츠랜드 엘티디. Air supply device for a ship, a ship comprising the same, and a method for supplying air to an air lubrication device

Also Published As

Publication number Publication date
JP5614235B2 (en) 2014-10-29

Similar Documents

Publication Publication Date Title
US9188050B2 (en) Engine cooling system
US9816432B2 (en) Engine cooling system
JP4802992B2 (en) Exhaust gas recirculation device for internal combustion engine
US10458369B2 (en) Supercharged internal combustion engine with cooled exhaust-gas recirculation arrangement
JP5614235B2 (en) Intake air cooling system for two-stage supercharging system
JP5899835B2 (en) Engine cooling system
JP5204609B2 (en) Engine control device
JP6414194B2 (en) Control device for internal combustion engine
US10024230B2 (en) Engine system and controller, control system and control method for engine system
JP2010185374A (en) Control system for internal combustion engine with supercharger
JP2014001703A (en) Cooling system of internal combustion engine
JP2005264821A (en) Exhaust reflux system of internal combustion engine
JP4882688B2 (en) Exhaust gas recirculation device for internal combustion engine
JP5617721B2 (en) Control device for supercharged engine with EGR device
WO2013011768A1 (en) Engine cooling circuit
JP2020180574A (en) Cooling device for internal combustion engine
JP6357902B2 (en) Engine exhaust gas recirculation method and exhaust gas recirculation device
JP2021080888A (en) EGR device
KR20120062095A (en) Apparatus for cooling the charged air of diesel engine with water cooling type intercooler and cooling method therefor
JP4775196B2 (en) Engine supercharger
JP2008240630A (en) Exhaust emission control device of diesel engine
JP7135402B2 (en) cooling system
JP5589953B2 (en) EGR device
JP5983453B2 (en) Intake air cooling system
JP2012219634A (en) Control device for internal combustion engine with egr device

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20130919

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20140527

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20140529

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140718

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

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20140812

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20140825

R150 Certificate of patent or registration of utility model

Ref document number: 5614235

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

LAPS Cancellation because of no payment of annual fees