JP2006009744A

JP2006009744A - Egr cooler

Info

Publication number: JP2006009744A
Application number: JP2004190899A
Authority: JP
Inventors: Takashi Ishimori; 崇石森
Original assignee: Hino Motors Ltd
Current assignee: Hino Motors Ltd
Priority date: 2004-06-29
Filing date: 2004-06-29
Publication date: 2006-01-12

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR cooler achieving reduction of NOx without enlarging capacity of an engine cooling system. <P>SOLUTION: In a flat tube 11 in which cooling water W circulates, elements 14 touching an outer surface bent part of the tube 11 at both edge parts and having a pair of trough shape shells 13 forming an exhaust gas passage 12 in a gap with an outer surface flat part built therein is provided, a plurality of the elements 14 are arranged in parallel to make air flow A hit an outer surface of the shell 14, and an outer part radiation fin 15 is provided between adjoining elements 14 to touch the outer surface of the shell 13. In other words, part of heat of exhaust gas G is given to air flow A of outer part of the shell 13 and is discharged to outer air separately from discharging heat of exhaust gas G to outer air via cooling water W. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明はＥＧＲクーラに関するものである。 The present invention relates to an EGR cooler.

従来、排気再循環（ＥＧＲ:Exhaust Gas Recirculation）を適用した過給機付内燃機関では、エンジン排気経路から分流した排気を、ＥＧＲクーラ（水冷方式の管形熱交換器）が組み込んであるＥＧＲ管路によりエンジン吸気経路へ送給し、燃焼温度の低下を図ってＮＯｘの発生を低減させている（例えば、特許文献１、非特許文献１参照）。 Conventionally, in an internal combustion engine with a supercharger to which exhaust gas recirculation (EGR) is applied, an EGR pipe in which an EGR cooler (water-cooled tubular heat exchanger) is incorporated into the exhaust gas diverted from the engine exhaust path. The fuel is fed to the engine intake path by the road, and the generation of NOx is reduced by reducing the combustion temperature (see, for example, Patent Document 1 and Non-Patent Document 1).

図６は従来のＥＧＲ装置の一例の冷却水流通系を示すもので、ＥＧＲクーラ１の冷却水入口を、ウォータポンプ２からエンジン３のウォータジャケットへ冷却水を送給する入口流路４に接続し、ＥＧＲクーラ１の冷却水出口を、エンジン３のウォータジャケットから冷却水を送出する出口流路５に接続している。 FIG. 6 shows a cooling water flow system as an example of a conventional EGR device, in which the cooling water inlet of the EGR cooler 1 is connected to an inlet flow path 4 for supplying cooling water from the water pump 2 to the water jacket of the engine 3. The cooling water outlet of the EGR cooler 1 is connected to the outlet flow path 5 for sending the cooling water from the water jacket of the engine 3.

すなわち、排気流路から分流した排気は、ＥＧＲクーラ１を流れる冷却水によって冷却される。 That is, the exhaust gas diverted from the exhaust passage is cooled by the cooling water flowing through the EGR cooler 1.

また、出口流路５にはサーモスタット６とラジエータ７が付帯し、エンジン３から送出される冷却水は、その温度が高いと、ラジエータ７を経てウォータポンプ２に戻り、反対に温度が低いと、ラジエータ７を経ずにウォータポンプ２に戻る。
特開平９−２５６９１５号公報「エンジン解剖学」ワーキングビークルズＮｏ．２５株式会社ぽると出版、平成１６年４月５日、ｐ．３３−３５ Further, a thermostat 6 and a radiator 7 are attached to the outlet channel 5, and when the temperature of the cooling water delivered from the engine 3 is high, it returns to the water pump 2 via the radiator 7, and conversely, when the temperature is low, Return to the water pump 2 without passing through the radiator 7.
Japanese Patent Laid-Open No. 9-256915 “Engine Anatomy” Working Vehicles 25 POTO PUBLISHING CO., LTD., April 5, 2004, p. 33-35

ＮＯｘの低減にはＥＧＲシステムが有効だが、排気再循環の量を今まで以上に増やすとなると、ラジエータ７などのエンジン冷却系を大容量化する必要が生じ、車両への搭載が難しくなる。 Although the EGR system is effective for reducing NOx, if the amount of exhaust gas recirculation is increased more than before, it is necessary to increase the capacity of the engine cooling system such as the radiator 7 and it becomes difficult to mount it on the vehicle.

本発明は上述した実情に鑑みてなしたもので、エンジン冷却系を大容量化せずにＮＯｘの低減を達成できるＥＧＲクーラを提供することを目的としている。 The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an EGR cooler that can achieve NOx reduction without increasing the capacity of an engine cooling system.

上記目的を達成するために、請求項１に記載の発明は、冷却水が流通するチューブを、排気が流通するシェルの内部に組み込んだエレメントを備え、空気流がシェル外面に当たるようにエレメントを配置している。 In order to achieve the above object, the invention described in claim 1 is provided with an element in which a tube through which cooling water flows is incorporated in a shell through which exhaust gas flows, and the element is arranged so that an air flow hits the outer surface of the shell. is doing.

請求項２に記載の発明は、冷却水が流通する扁平状のチューブを、当該チューブ外面湾曲部分に両縁部分が接してチューブ外面扁平部分との間に排気通路を形成する一対のトラフ状のシェルに組み込んだエレメントを備え、空気流がシェル外面に当たるようにエレメントを配置している。 The invention according to claim 2 is a pair of trough-shaped tubes in which a cooling tube circulates a flat tube, and both edge portions are in contact with the tube outer surface curved portion to form an exhaust passage between the tube outer surface flat portion. The element is incorporated in the shell and is arranged so that the air flow strikes the shell outer surface.

請求項３に記載の発明は、複数のエレメントを並べ、隣り合ったエレメントの間に外部放熱フィンをシェル外面に接するように設けている。 According to a third aspect of the present invention, a plurality of elements are arranged, and an external radiating fin is provided in contact with the outer surface of the shell between adjacent elements.

請求項１に記載の発明においては、シェル内部を流通する排気の熱を、チューブを流通している冷却水とシェル外部の空気流に授けて外気へ放出する。 In the first aspect of the present invention, the heat of the exhaust gas flowing through the inside of the shell is given to the cooling water flowing through the tube and the air flow outside the shell to be released to the outside air.

請求項２に記載の発明においては、排気通路へ導いた排気の熱を、チューブを流通している冷却水とシェル外部の空気流に授けて外気へ放出する。 According to the second aspect of the present invention, the heat of the exhaust led to the exhaust passage is given to the cooling water flowing through the tube and the air flow outside the shell to be released to the outside air.

請求項３に記載の発明においては、排気の熱を、外部放熱フィンを介してシェル外部の空気流に授けて外気へ放出する。 In the invention according to claim 3, the heat of the exhaust is given to the air flow outside the shell through the external heat radiation fins and released to the outside air.

本発明のＥＧＲクーラによれば、冷却水による放熱とは別に、排気の熱の一部をシェル外部の空気流に授けて外気へ放出するので、エンジン冷却系の大容量化を図らずとも排気再循環の量を増やすことが可能になり、よって、車両搭載性を確保しつつＮＯｘの低減を達成できる、という優れた効果を奏し得る。 According to the EGR cooler of the present invention, apart from heat radiation by the cooling water, a part of the heat of the exhaust is given to the air flow outside the shell and released to the outside air, so that the exhaust gas can be exhausted without increasing the capacity of the engine cooling system. It is possible to increase the amount of recirculation, and therefore, it is possible to achieve an excellent effect that NOx reduction can be achieved while ensuring vehicle mountability.

以下、本発明の実施の形態を図面に基づき説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１乃至図５は本発明のＥＧＲクーラの実施の形態の一例を示すものであり、冷却水Ｗが流通する扁平状のチューブ１１を、当該チューブ１１外面湾曲部分に両縁部分が接して外面平坦部分との間に排気通路１２を形成する一対のトラフ状のシェル１３に組み込んだエレメント１４を備え、空気流Ａがシェル１３外面に当たるように複数のエレメント１４を平行に並べ、隣り合ったエレメント１４の間に外部放熱フィン１５をシェル１３外面に接するように設けている。 1 to 5 show an example of an embodiment of an EGR cooler according to the present invention. A flat tube 11 through which cooling water W circulates has an outer surface in which both edge portions are in contact with the outer curved portion of the tube 11. An element 14 incorporated in a pair of trough-shaped shells 13 forming an exhaust passage 12 between the flat portions and a plurality of elements 14 arranged in parallel so that the air flow A hits the outer surface of the shell 13, adjacent elements 14, external heat radiation fins 15 are provided in contact with the outer surface of the shell 13.

チューブ１１は、ごく浅いトラフ状で、両縁部分に全長にわたって延びるフランジ１６を有し且つ凹面から突き出るエンボス１７を形成した一対の板金材１８を構成要素とし、凹面が向き合うように配置した板金材１８のフランジ１６、及びエンボス１７のそれぞれを相互にろう付で接合したものである。 The tube 11 has a very shallow trough shape, and has a pair of sheet metal members 18 having flanges 16 extending over the entire length at both edge portions and formed with an emboss 17 projecting from the concave surface, and is arranged so that the concave surfaces face each other. Each of the 18 flanges 16 and the emboss 17 is joined to each other by brazing.

エンボス１７は板金材１８の変形防止を主な目的として設けてあるが、これの他に伝熱部材としての役割も担っている。 The emboss 17 is provided mainly for the purpose of preventing deformation of the sheet metal material 18, but also plays a role as a heat transfer member.

シェル１３は、チューブ１１よりも短く、両縁部分から外方へ突出するフランジ１９を全長にわたって有し、かしめ加工により当該フランジ１９をチューブ１１のフランジ１６に締結したうえ、フランジ１９、並びに両縁部分をチューブ１１外面湾曲部分にろう付で接合してあり、冷却対象となる排気Ｇが導かれる排気通路１２を形成している。 The shell 13 has a flange 19 that is shorter than the tube 11 and protrudes outward from both edge portions over the entire length. The flange 19 is fastened to the flange 16 of the tube 11 by caulking. The portion is joined to the outer curved portion of the tube 11 by brazing, and an exhaust passage 12 through which the exhaust G to be cooled is guided is formed.

シェル１３の両端部分は、排気Ｇの流通方向に見て一対のシェル１３が矩形開口を形成するように拡がっている。 Both end portions of the shell 13 are spread so that the pair of shells 13 form a rectangular opening when viewed in the flow direction of the exhaust G.

シェル１３凹面とチューブ１１外面平坦部分との間には、これらの双方に接するようにコルゲート状の内部放熱フィン２０が介在させてあり、当該内部放熱フィン２０はシェル１３、並びにチューブ１１にろう付で接合してある。 Between the concave surface of the shell 13 and the flat portion of the outer surface of the tube 11, a corrugated internal heat radiating fin 20 is interposed so as to be in contact with both of them, and the internal heat radiating fin 20 is brazed to the shell 13 and the tube 11. Are joined together.

シェル１３凹面とチューブ１１外面平坦部分を接合する内部放熱フィン２０の縦壁部分には、排気Ｇの流れを乱して熱交換効率の向上を図るための開口などを適宜に設けておくことが望ましい。 The vertical wall portion of the internal radiating fin 20 that joins the concave surface of the shell 13 and the flat portion of the outer surface of the tube 11 may be appropriately provided with an opening for disturbing the flow of the exhaust G and improving the heat exchange efficiency. desirable.

外部放熱フィン１５もコルゲート状で、シェル１３にろう付で接合してあり、当該外部放熱フィン１５の形状（寸法）は、隣り合っているエレメント１４のシェル１３両端開口外縁が相互に接するように設定されている。 The external radiating fin 15 is also corrugated and joined to the shell 13 by brazing, and the shape (dimension) of the external radiating fin 15 is such that the outer edges of both ends of the shell 13 adjacent to each other are in contact with each other. Is set.

更に、エレメント１４、及び外部放熱フィン１５の素材には、アルミニウム合金などのような伝熱性に優れ、軽量で適度な機械的強度を具備した金属を用いる。 Further, as the material for the element 14 and the external heat radiation fin 15, a metal having excellent heat conductivity, such as an aluminum alloy, and having a light weight and appropriate mechanical strength is used.

チューブ１１外面湾曲部分とシェル１３両縁部分、シェル１３と外部放熱フィン１５、チューブ１１外面平坦部分やシェル１３凹面と内部放熱フィン２０、及びフランジ１６，１９の締結部分に関して追記すると、実際の組み上がり状態ではこれらの間に空隙は形成されないが、明細書に添付の図面の一部では、部材の形状や位置関係を明確に把握できるようにするために、あえて空隙を介在させてある。 The tube 11 outer curved portion and the shell 13 both edge portions, the shell 13 and the outer radiating fin 15, the tube 11 outer flat portion, the shell 13 concave surface and the inner radiating fin 20, and the fastening portions of the flanges 16 and 19 will be added. In the upward state, no gap is formed between them, but in some of the drawings attached to the specification, a gap is intentionally interposed in order to make it possible to clearly grasp the shape and positional relationship of the members.

複数のエレメント１４と外部放熱フィン１５で構成される集合体の両端部分には、内側コアプレート２１、排気チャンバ２２、外側コアプレート２３、及び冷却水チャンバ２４が付帯している。 An inner core plate 21, an exhaust chamber 22, an outer core plate 23, and a cooling water chamber 24 are attached to both end portions of the assembly composed of the plurality of elements 14 and the external heat radiation fins 15.

内側コアプレート２１に穿設してある大きな開口には、シェル１３端部が嵌まり込み、また、排気チャンバ２２は、両端部分のそれぞれが全面的に開き且つこれとは別に排気Ｇの流通口２５を設けた中空構造の直方体であり、その一端部分に内側コアプレート２１が嵌まり込んでいる。 The end of the shell 13 is fitted into a large opening formed in the inner core plate 21. Further, the exhaust chamber 22 is opened at both ends of the exhaust chamber 22 and the exhaust G circulation port is provided separately. The inner core plate 21 is fitted into one end of the rectangular parallelepiped having a hollow structure 25.

外側コアプレート２３に穿設してあるエレメント１４と同じ数の開口には、シェル１３よりも長いチューブ１１端部が貫通し、外側コアプレート２３自体は、排気チャンバ２２の他端部分に嵌まり込んでいる。 The end of the tube 11 longer than the shell 13 passes through the same number of openings as the elements 14 drilled in the outer core plate 23, and the outer core plate 23 itself fits into the other end portion of the exhaust chamber 22. It is crowded.

冷却水チャンバ２４は、一端部分だけが全面的に開き且つ冷却水Ｗの流通管２６を取り付けた中空構造の直方体であり、一端部分に排気チャンバ２２の他端部分が嵌まり込んでいる。 The cooling water chamber 24 is a rectangular parallelepiped having a hollow structure in which only one end portion is opened entirely and a circulation pipe 26 for the cooling water W is attached, and the other end portion of the exhaust chamber 22 is fitted into the one end portion.

図２では、排気Ｇの出側の排気チャンバ２２と冷却水Ｗの入側の冷却水チャンバ２４を示しているが、排気Ｇの入側や冷却水Ｗの出側も基本的に同じ構造となっている。 FIG. 2 shows the exhaust chamber 22 on the outlet side of the exhaust G and the cooling water chamber 24 on the inlet side of the cooling water W, but the inlet side of the exhaust G and the outlet side of the cooling water W have basically the same structure. It has become.

内側コアプレート２１や外側コアプレート２３と排気チャンバ２２、内側コアプレート２１とシェル１３、外側コアプレート２３とチューブ１１、並びに冷却水チャンバ２４と排気チャンバ２２は、ろう付で接合してある。 The inner core plate 21, the outer core plate 23 and the exhaust chamber 22, the inner core plate 21 and the shell 13, the outer core plate 23 and the tube 11, and the cooling water chamber 24 and the exhaust chamber 22 are joined by brazing.

排気通路１２とその両端の排気チャンバ２２からなる流通経路は、ＥＧＲ管路に直列に組み込まれ、チューブ１１とその両端の冷却水チャンバ２４から流通経路は、エンジン３の冷却水循環系（図６参照）に並列に組み込まれている。 A circulation path composed of the exhaust passage 12 and the exhaust chambers 22 at both ends thereof is incorporated in series with the EGR pipe, and a circulation path from the tube 11 and the cooling water chambers 24 at both ends thereof is connected to the cooling water circulation system of the engine 3 (see FIG. 6). ) In parallel.

図１乃至図５に示すＥＧＲクーラでは、エンジン排気経路から排気通路１２へ導かれる排気Ｇの熱を、内部放熱フィン２０、板金材１８、並びにエンボス１７を介してチューブ１１内を流通している冷却水Ｗに授けてラジエータ７（図６参照）から外気へ放出する。 In the EGR cooler shown in FIGS. 1 to 5, the heat of the exhaust G guided from the engine exhaust path to the exhaust passage 12 is circulated in the tube 11 through the internal heat radiation fins 20, the sheet metal material 18, and the emboss 17. It is given to the cooling water W and discharged from the radiator 7 (see FIG. 6) to the outside air.

また、排気Ｇの熱を、内部放熱フィン２０、シェル１３、並びに外部放熱フィン１５を介してエレメント１４間を流通している空気流Ａに授けて外気へ放出する。 Further, the heat of the exhaust G is imparted to the air flow A flowing between the elements 14 via the internal radiating fins 20, the shell 13, and the external radiating fins 15, and released to the outside air.

つまり、排気Ｇの熱を冷却水Ｗを介して外気へ放出することは別に、排気Ｇの熱の一部をシェル１３外部の空気流Ａに授けて外気へ放出するので、エンジン冷却系の大容量化を図らずとも排気再循環の量を増やすことが可能になり、車両搭載性を確保しつつＮＯｘの低減を達成できる。 That is, apart from releasing the heat of the exhaust G to the outside air through the cooling water W, a part of the heat of the exhaust G is given to the air flow A outside the shell 13 and released to the outside air, so that the engine cooling system is large. It is possible to increase the amount of exhaust gas recirculation without increasing the capacity, and it is possible to achieve a reduction in NOx while ensuring vehicle mountability.

更に、チューブ１１、内部放熱フィン２０、シェル１３を積み重ねる構造のエレメント１４で外部放熱フィン１５を挟んだ集合体を内側コアプレート２１に嵌め込み、当該内側コアプレート２１に、排気チャンバ２２、外側コアプレート２３、冷却水チャンバ２４を順に組み付けるのにあたって、ろう材及びフラックスを部材接合対象面に塗布しておいたうえ、熱処理炉で一体的に加熱すれば、各部材の接合が同時に行なえる。 Further, an assembly in which the external heat radiation fin 15 is sandwiched by the elements 14 having a structure in which the tube 11, the internal heat radiation fins 20 and the shell 13 are stacked is fitted into the inner core plate 21. 23, when assembling the cooling water chamber 24 in order, the brazing material and the flux are applied to the surface to be joined to the members, and then heated together in a heat treatment furnace, the members can be joined at the same time.

なお、本発明のＥＧＲクーラは上述の実施の形態だけに特に限定されるものではなく、本発明の要旨を逸脱しない範囲において変更を加え得ることは勿論である。 Note that the EGR cooler of the present invention is not particularly limited to the above-described embodiment, and it goes without saying that modifications can be made without departing from the scope of the present invention.

本発明のＥＧＲクーラは、様々な車種に適用できる。 The EGR cooler of the present invention can be applied to various vehicle types.

本発明のＥＧＲクーラの実施の形態の一例を示す部分斜視図である。It is a fragmentary perspective view which shows an example of embodiment of the EGR cooler of this invention. 本発明のＥＧＲクーラの実施の形態の一例を示す部分切断図である。It is a partial cutaway figure showing an example of an embodiment of an EGR cooler of the present invention. 図２のＩＩＩ−ＩＩＩ矢視図である。It is the III-III arrow line view of FIG. 図２のＩＶ−ＩＶ矢視図である。It is the IV-IV arrow line view of FIG. 図３のＶ−Ｖ矢視図である。It is a VV arrow line view of FIG. 従来のＥＧＲ装置の一例の冷却水流通系を示す概念図である。It is a conceptual diagram which shows the cooling water distribution system of an example of the conventional EGR apparatus.

Explanation of symbols

１１チューブ
１２排気通路
１３シェル
１４エレメント
１５放熱フィン
Ａ空気流
Ｇ排気
Ｗ冷却水 11 Tube 12 Exhaust passage 13 Shell 14 Element 15 Radiation fin A Air flow G Exhaust W Cooling water

Claims

An EGR cooler comprising an element in which a tube through which cooling water circulates is incorporated in a shell through which exhaust gas circulates, and wherein the elements are arranged so that an air flow strikes the outer surface of the shell.

A flat tube through which cooling water circulates is provided with an element incorporated in a pair of trough-shaped shells that form an exhaust passage between the tube outer surface flat part with both edge parts in contact with the tube outer surface curved part, and air An EGR cooler characterized in that the elements are arranged so that the flow hits the outer surface of the shell.

The EGR cooler according to claim 1, wherein a plurality of elements are arranged and an external heat radiation fin is provided between adjacent elements so as to contact the outer surface of the shell.