JP2009002300A - Egr cooler - Google Patents

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JP2009002300A
JP2009002300A JP2007166271A JP2007166271A JP2009002300A JP 2009002300 A JP2009002300 A JP 2009002300A JP 2007166271 A JP2007166271 A JP 2007166271A JP 2007166271 A JP2007166271 A JP 2007166271A JP 2009002300 A JP2009002300 A JP 2009002300A
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cooling water
egr gas
shell
egr
pipe
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Yushi Naito
雄史 内藤
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UD Trucks Corp
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UD Trucks Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR cooler capable of suppressing nucleate boiling on an EGR gas inlet side and a consequent secondary problem. <P>SOLUTION: An EGR gas inlet pipe and an EGR gas outlet pipe are connected to both ends of a cylindrical shell via diffusers, and a plurality of tubes opened in the diffusers are inserted and attached between end plates blocking both ends of the shell. Moreover, a cooling water inlet pipe is connected to the peripheral wall of the shell on the EGR gas inlet pipe side, and a cooling water outlet pipe is connected to the peripheral wall of the shell on the EGR gas outlet pipe side. In this EGR cooler, the tubes are provided with means for enhancing heat exchanging efficiency between the cooling water and the EGR gas excluding the EGR gas inlet side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、ディーゼルエンジンのＥＧＲ装置に用いるＥＧＲクーラーに関する。   The present invention relates to an EGR cooler used for an EGR device of a diesel engine.

ディーゼルエンジン（以下、「エンジン」という）の燃焼時に発生する窒素酸化物（ＮＯX ）を低減するため、従来、排ガスの一部をエンジンの吸気系に排気還流（以下、「ＥＧＲ」
という）させるＥＧＲ装置が知られている。 In order to reduce nitrogen oxide (NO x ) generated during combustion of a diesel engine (hereinafter referred to as “engine”), conventionally, a part of the exhaust gas is exhausted to the engine intake system (hereinafter referred to as “EGR”).
EGR devices are known.

窒素酸化物は、高温の排ガスのもとで空気中の酸素と窒素が反応して生成されるため、ＥＧＲ装置は、ＥＧＲによって燃焼温度を下げることでＯ2＋Ｎ2→２ＮＯの反応を抑制して窒素酸化物の排出を低減させるものである。そして、吸気系にＥＧＲさせるＥＧＲガスの温度を下げるほど、燃焼時のスモークの悪化を抑え、窒素酸化物の発生が減少することが知られている。 Since nitrogen oxides are produced by the reaction of oxygen and nitrogen in the air under high temperature exhaust gas, the EGR device suppresses the reaction of O 2 + N 2 → 2NO by lowering the combustion temperature with EGR. This reduces nitrogen oxide emissions. It is known that as the temperature of the EGR gas to be EGRed into the intake system is lowered, the deterioration of smoke during combustion is suppressed and the generation of nitrogen oxides is reduced.

そこで、昨今では、特許文献１に開示されるように、エンジンの吸気系と排気系との間に接続したＥＧＲパイプに、エンジンの冷却水を冷媒とするＥＧＲクーラーを装着し、ＥＧＲパイプを流下するＥＧＲガスをこのＥＧＲクーラーで熱交換させて、ＥＧＲガス温度を下げる方法が広く採用されている。   Therefore, recently, as disclosed in Patent Document 1, an EGR cooler using coolant of the engine as a refrigerant is attached to the EGR pipe connected between the intake system and the exhaust system of the engine, and the EGR pipe flows down. The method of lowering the EGR gas temperature by causing the EGR gas to exchange heat with the EGR cooler is widely adopted.

図３はこの種のＥＧＲクーラーを示し、このＥＧＲクーラー１は、筒状に成形されたシェル３内に、その長手方向に沿って複数の均一内径のチューブ５を収容し、シェル３のＥＧＲガス上流側端部とＥＧＲガス下流側端部に取り付くディフューザ７，９に、夫々、図示しないＥＧＲガス導入パイプ（ＥＧＲパイプ）とＥＧＲガス導出パイプ（ＥＧＲパイプ）をフランジ１１を介して接続すると共に、ＥＧＲガス導入パイプ側のシェル３の周壁に冷却水導入パイプ１３を接続し、ＥＧＲガス導出パイプ側のシェル３の周壁に冷却水導出パイプ１５を接続したもので、チューブ５は、夫々、シェル３の両端部に取り付くエンドプレート１７，１９に挿着されて両ディフューザ７，９内に開口している。   FIG. 3 shows an EGR cooler of this type. The EGR cooler 1 accommodates a plurality of tubes 5 having a uniform inner diameter along the longitudinal direction in a shell 3 formed into a cylindrical shape. An EGR gas introduction pipe (EGR pipe) and an EGR gas outlet pipe (EGR pipe) (not shown) are connected to the diffusers 7 and 9 attached to the upstream end and the EGR gas downstream end via the flange 11, respectively. The cooling water introduction pipe 13 is connected to the peripheral wall of the shell 3 on the EGR gas introduction pipe side, and the cooling water extraction pipe 15 is connected to the peripheral wall of the shell 3 on the EGR gas extraction pipe side. Are inserted into end plates 17 and 19 which are attached to both ends of the diffuser and are opened in both diffusers 7 and 9.

而して、斯かる構造によって、シェル３内に導入されたＥＧＲガスＧがチューブ５内を流下する際に、シェル３内に導入された冷却水Ｗで熱交換されてＥＧＲガス温度が下がるようになっている。   Thus, with this structure, when the EGR gas G introduced into the shell 3 flows down through the tube 5, heat is exchanged with the cooling water W introduced into the shell 3 so that the EGR gas temperature is lowered. It has become.

また、冷却水ＷとＥＧＲガスＧとの熱交換効率を高めるため、特許文献２または図３に示すように、ＥＧＲガスＧが流下するチューブ５の全長に亘って内方に突出する複数の突起２１を内周に設けたり、特許文献１に開示されるように、チューブの外周に冷却フィンをチューブの長手方向に複数突設する等の手段が、ＥＧＲクーラーのチューブに施されている。
特開２００４−３４６９１９号公報 特開２００４−８５０９０号公報 Further, in order to increase the heat exchange efficiency between the cooling water W and the EGR gas G, as shown in Patent Document 2 or FIG. 3, a plurality of protrusions projecting inward over the entire length of the tube 5 through which the EGR gas G flows down. The EGR cooler tube is provided with means such as 21 provided on the inner periphery or a plurality of cooling fins protruding in the longitudinal direction of the tube on the outer periphery of the tube as disclosed in Patent Document 1.
JP 2004-346919 A JP 2004-85090 A

しかし、冷却水導入パイプ１３から流入した冷却水Ｗはシェル３内を一様に流れず、図３に示すように冷却水導入パイプ１３から冷却水導出パイプ１５に亘って主冷却水流路Ｗ１が形成され、冷却水導入パイプ１３から流入した冷却水ＷがＥＧＲガス入口側のエンドプレート１７に沿って流れ難いのが実情であった。   However, the cooling water W flowing in from the cooling water introduction pipe 13 does not flow uniformly in the shell 3, and the main cooling water flow path W1 extends from the cooling water introduction pipe 13 to the cooling water outlet pipe 15 as shown in FIG. The actual situation is that the cooling water W formed and flowing from the cooling water introduction pipe 13 hardly flows along the end plate 17 on the EGR gas inlet side.

このため、図中、Ａで示すＥＧＲガス入口側の領域に冷却水Ｗの澱みが生じ、そして、この領域ＡはＥＧＲガス温度が非常に高温で、また、チューブ５に突起２１を設けて熱交換効率を高めていることも相俟って、単位水当たりの仕事量（熱交換量）が高くなってこの領域Ａで核沸騰が発生し、長期に亘る使用でチューブ５とエンドプレート１７との接合部に亀裂が発生してしまう虞があった。   Therefore, stagnation of the cooling water W occurs in the region on the EGR gas inlet side indicated by A in the figure, and in this region A, the EGR gas temperature is very high, and the projections 21 are provided on the tube 5 to heat the region. Combined with the improvement of the exchange efficiency, the work amount per unit water (heat exchange amount) becomes high and nucleate boiling occurs in this region A, and the tube 5 and end plate 17 There was a risk of cracks occurring at the joints.

そして、特に、チューブに前記突起２１や冷却フィン等の熱交換効率を高める手段が施されたＥＧＲクーラー１は、このようなＥＧＲガス入口側の領域Ａでの核沸騰及びこれに起因する２次不具合（チューブ５とエンドプレート１７との接合部の亀裂）の危険性が高いことが知られている。   In particular, the EGR cooler 1 in which the tube is provided with means for improving the heat exchange efficiency such as the protrusions 21 and the cooling fins, the nucleate boiling in the region A on the EGR gas inlet side and the secondary caused by this. It is known that there is a high risk of malfunction (cracking at the joint between the tube 5 and the end plate 17).

本発明は斯かる実情に鑑み案出されたもので、上述の如きＥＧＲガス入口側の核沸騰及びこれに起因する２次不具合を抑制したＥＧＲクーラーを提供することを目的とする。   The present invention has been devised in view of such circumstances, and an object of the present invention is to provide an EGR cooler that suppresses nucleate boiling on the EGR gas inlet side as described above and secondary problems resulting therefrom.

斯かる目的を達成するため、請求項１に係る発明は、筒状のシェルの両端部に、ディフューザを介してＥＧＲガス導入パイプとＥＧＲガス導出パイプを接続し、シェルの両端部を閉塞するエンドプレート間に、ディフューザ内に開口する複数のチューブを挿着すると共に、ＥＧＲガス導入パイプ側のシェルの周壁に冷却水導入パイプを接続し、ＥＧＲガス導出パイプ側のシェルの周壁に冷却水導出パイプを接続したＥＧＲクーラーに於て、ＥＧＲガス入口側を除いて前記チューブに、冷却水とＥＧＲガスとの熱交換効率を高める手段を施したことを特徴とする。   In order to achieve such an object, the invention according to claim 1 is an embodiment in which an EGR gas introduction pipe and an EGR gas outlet pipe are connected to both ends of a cylindrical shell via a diffuser, and both ends of the shell are closed. A plurality of tubes opened in the diffuser are inserted between the plates, a cooling water introduction pipe is connected to the peripheral wall of the shell on the EGR gas introduction pipe side, and the cooling water extraction pipe is connected to the peripheral wall of the shell on the EGR gas extraction pipe side In the EGR cooler to which is connected, means for increasing the heat exchange efficiency between the cooling water and the EGR gas is provided on the tube except for the EGR gas inlet side.

また、請求項２に係る発明は、筒状のシェルの両端部に、ディフューザを介してＥＧＲガス導入パイプとＥＧＲガス導出パイプを接続し、シェルの両端部を閉塞するエンドプレート間に、ディフューザ内に開口する複数のチューブを挿着すると共に、ＥＧＲガス導入パイプ側のシェルの周壁に冷却水導入パイプを接続し、ＥＧＲガス導出パイプ側のシェルの周壁に冷却水導出パイプを接続したＥＧＲクーラーに於て、前記冷却水導入パイプから冷却水導出パイプに亘ってシェル内に形成される冷却水の主冷却水流路中のチューブの部位に、冷却水とＥＧＲガスとの熱交換効率を高める手段を施したことを特徴とする。   In the invention according to claim 2, the EGR gas introduction pipe and the EGR gas outlet pipe are connected to both ends of the cylindrical shell via the diffuser, and the end plate is closed between the end plates closing the both ends of the shell. In the EGR cooler, a plurality of tubes are inserted into the EGR gas inlet pipe, a cooling water introduction pipe is connected to the peripheral wall of the shell on the EGR gas introduction pipe side, and a cooling water extraction pipe is connected to the peripheral wall of the shell on the EGR gas extraction pipe side. And means for increasing the heat exchange efficiency between the cooling water and the EGR gas at a tube portion in the main cooling water flow passage formed in the shell from the cooling water introduction pipe to the cooling water outlet pipe. It is characterized by that.

そして、請求項３に係る発明は、請求項１または請求項２に記載のＥＧＲクーラーに於て、冷却水とＥＧＲガスとの熱交換効率を高める手段は、チューブ内面に突出する複数の突起であることを特徴とし、請求項４に係る発明は、請求項１または請求項２に記載のＥＧＲクーラーに於て、冷却水とＥＧＲガスとの熱交換効率を高める手段は、チューブの外周に設けた冷却フィンであることを特徴とする。   The invention according to claim 3 is the EGR cooler according to claim 1 or 2, wherein the means for increasing the heat exchange efficiency between the cooling water and the EGR gas is a plurality of protrusions protruding on the inner surface of the tube. According to a fourth aspect of the present invention, in the EGR cooler according to the first or second aspect, the means for increasing the heat exchange efficiency between the cooling water and the EGR gas is provided on the outer periphery of the tube. It is characterized by being a cooling fin.

各請求項に係る発明によれば、ＥＧＲガス入口側のエンドプレートに沿った冷却水流れの澱みによる核沸騰が抑制でき、核沸騰に起因する２次不具合（チューブとエンドプレートとの接合部の亀裂）の危険性を軽減することが可能となって、ＥＧＲ装置の耐久信頼性の向上が図れる利点を有する。   According to the invention according to each claim, nucleate boiling due to stagnation of the cooling water flow along the end plate on the EGR gas inlet side can be suppressed, and a secondary failure caused by nucleate boiling (of the junction between the tube and the end plate) can be suppressed. It is possible to reduce the risk of cracks), and there is an advantage that the durability reliability of the EGR device can be improved.

また、冷却水流量増加による核沸騰抑制という手段が従来周知であるが、この手段は、エンジン補機消費馬力の増加による燃費の悪化という問題点が懸念されている。しかし、本発明によれば斯かる問題点も回避可能である。   Further, a means of suppressing nucleate boiling by increasing the coolant flow rate is well known, but this means is concerned with a problem of deterioration of fuel consumption due to an increase in horsepower consumption of engine accessories. However, according to the present invention, such a problem can be avoided.

以下、本発明の実施形態を図面に基づいて詳細に説明する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

図１は請求項１及び請求項３の一実施形態に係るＥＧＲクーラーを示し、図に於て、２３は筒状に成形されたシェルで、シェル２３内に、その長手方向に沿って複数の均一内径のチューブ２５が収容され、シェル２３のＥＧＲガス上流側端部とＥＧＲガス下流側端部に取り付くディフューザ２７，２９に、夫々、フランジ３１を介して図示しないＥＧＲガス導入パイプとＥＧＲガス導出パイプが接続されている。   FIG. 1 shows an EGR cooler according to an embodiment of claims 1 and 3. In the figure, reference numeral 23 denotes a shell formed in a cylindrical shape, and a plurality of shells are formed in the shell 23 along the longitudinal direction thereof. A tube 25 having a uniform inner diameter is accommodated, and an EGR gas introduction pipe (not shown) and an EGR gas lead-out are respectively connected to the diffusers 27 and 29 attached to the EGR gas upstream end and the EGR gas downstream end of the shell 23 via the flange 31. The pipe is connected.

また、ＥＧＲガス導入パイプ側（ＥＧＲガス入口側）のシェル２３の周壁に冷却水導入パイプ３３が接続され、ＥＧＲガス導出パイプ側のシェル２３の周壁に冷却水導出パイプ３５が接続されている。そして、チューブ２５は、夫々、シェル２３の両端部に取り付くエンドプレート３７，３９に挿着されて両ディフューザ２７，２９内に開口しており、斯かる構造によって、冷却水導入パイプ３３から冷却水導出パイプ３５に亘って主冷却水流路Ｗ１が形成され、ＥＧＲガス導入パイプからチューブ２５を経てＥＧＲガス導出パイプに至るＥＧＲガス流路が形成されている。   A cooling water introduction pipe 33 is connected to the peripheral wall of the shell 23 on the EGR gas introduction pipe side (EGR gas inlet side), and a cooling water outlet pipe 35 is connected to the peripheral wall of the shell 23 on the EGR gas outlet pipe side. The tubes 25 are respectively inserted into end plates 37 and 39 attached to both ends of the shell 23 and opened in the diffusers 27 and 29. With such a structure, the cooling water is supplied from the cooling water introduction pipe 33 to the cooling water. A main cooling water passage W1 is formed over the outlet pipe 35, and an EGR gas passage is formed from the EGR gas introduction pipe through the tube 25 to the EGR gas outlet pipe.

このため、シェル２３内に導入されたＥＧＲガスＧがチューブ２５内を流下する際に、シェル２３内に導入された冷却水Ｗで熱交換されてＥＧＲガス温度が下がるようになっている。   For this reason, when the EGR gas G introduced into the shell 23 flows down in the tube 25, the EGR gas temperature is lowered by heat exchange with the cooling water W introduced into the shell 23.

このように本実施形態に係るＥＧＲクーラー４１も、図３のＥＧＲクーラー１と同様、冷却水導入パイプ３３から冷却水導出パイプ３５に亘って主冷却水流路Ｗ１が形成されるため、冷却水導入パイプ３３から流入した冷却水Ｗが、ＥＧＲガス入口側のエンドプレート３７に沿って流れ難く、図中、Ａで示すＥＧＲガス入口側の領域に冷却水Ｗの澱みが生じる。   As described above, the EGR cooler 41 according to the present embodiment also has the main cooling water flow path W1 formed from the cooling water introduction pipe 33 to the cooling water outlet pipe 35, similarly to the EGR cooler 1 of FIG. The cooling water W flowing in from the pipe 33 is difficult to flow along the end plate 37 on the EGR gas inlet side, and stagnation of the cooling water W occurs in the region on the EGR gas inlet side indicated by A in the drawing.

そこで、図示するように本実施形態は、従来、冷却水ＷとＥＧＲガスＧとの熱交換効率を高める手段としてチューブの内面に突設する複数の突起４３を、ＥＧＲガス入口側を除いて前記チューブ２５に設け、領域Ａに於けるチューブ２５内の突起４３を廃止したことを特徴とする。   Therefore, as shown in the drawing, this embodiment conventionally has a plurality of protrusions 43 protruding from the inner surface of the tube as means for increasing the heat exchange efficiency between the cooling water W and the EGR gas G, except for the EGR gas inlet side. It is provided in the tube 25, and the projection 43 in the tube 25 in the region A is abolished.

本実施形態はこのように構成されているから、既述したように冷却水導入パイプ３３から冷却水導出パイプ３５に亘って主冷却水流路Ｗ１が形成され、シェル２３内に導入されたＥＧＲガスＧがチューブ２５内を流下する際に、シェル２３内に導入された冷却水Ｗで熱交換される。   Since the present embodiment is configured as described above, as described above, the main cooling water flow path W1 is formed from the cooling water introduction pipe 33 to the cooling water outlet pipe 35, and the EGR gas introduced into the shell 23 is formed. When G flows down in the tube 25, heat is exchanged with the cooling water W introduced into the shell 23.

そして、冷却水導入パイプ３３から流入した冷却水Ｗは、エンドプレート３７に沿って流れ難く、領域Ａに冷却水Ｗの澱みが生じるが、本実施形態は、領域Ａを含むＥＧＲガス入口側のチューブ２５内の突起４３を廃止したため、図３の従来例に比し、ＥＧＲガス入口側のエンドプレート３７に沿った領域Ａでのチューブ２５の熱交換効率が低下し、この結果、単位水当たりの仕事量（熱交換量）が低下（冷却水流量に対する負荷が低減）することとなる。   And the cooling water W which flowed in from the cooling water introduction pipe 33 does not flow easily along the end plate 37, and the stagnation of the cooling water W occurs in the region A. However, in the present embodiment, the cooling water W on the EGR gas inlet side including the region A Since the protrusions 43 in the tube 25 are eliminated, the heat exchange efficiency of the tube 25 in the region A along the end plate 37 on the EGR gas inlet side is reduced as compared with the conventional example of FIG. The amount of work (heat exchange amount) decreases (the load on the coolant flow rate decreases).

従って、本実施形態によれば、ＥＧＲガス入口側のエンドプレート３７に沿った領域Ａでの冷却水流れの澱みによる核沸騰が抑制でき、この結果、核沸騰に起因する２次不具合（チューブ２５とエンドプレート３７との接合部の亀裂）の危険性を軽減することが可能となって、ＥＧＲ装置の耐久信頼性の向上が図れる利点を有する。   Therefore, according to the present embodiment, nucleate boiling due to stagnation of the cooling water flow in the region A along the end plate 37 on the EGR gas inlet side can be suppressed, and as a result, secondary defects (tube 25 caused by nucleate boiling) can be suppressed. It is possible to reduce the risk of cracks in the joint between the end plate 37 and the end plate 37, and there is an advantage that durability reliability of the EGR device can be improved.

また、冷却水流量増加による核沸騰抑制という手段が従来周知であるが、この手段は、エンジン補機消費馬力の増加による燃費の悪化という問題点が懸念されている。しかし、本実施形態によれば斯かる問題点も回避可能である。   Further, a means of suppressing nucleate boiling by increasing the coolant flow rate is well known, but this means is concerned with a problem of deterioration of fuel consumption due to an increase in horsepower consumption of engine accessories. However, according to this embodiment, such a problem can also be avoided.

図２は請求項２及び請求項３の一実施形態に係るＥＧＲクーラーを示し、図示するように本実施形態は、冷却水導入パイプ３３から冷却水導出パイプ３５に亘ってシェル２３内に形成される冷却水Ｗの主冷却水流路Ｗ１中のチューブ２５-1の部位の内周に複数の突起４３を設けて、主冷却水流路Ｗ１から外れ、冷却水流れの澱みが発生する領域Ａでのチューブ２５-1の突起４３を廃止したものである。   FIG. 2 shows an EGR cooler according to an embodiment of claims 2 and 3. As shown in the figure, this embodiment is formed in the shell 23 from the cooling water introduction pipe 33 to the cooling water outlet pipe 35. A plurality of protrusions 43 are provided on the inner periphery of the portion of the tube 25-1 in the main cooling water flow path W1 of the cooling water W to be removed from the main cooling water flow path W1 and the stagnation of the cooling water flow occurs in the region A. The protrusion 43 of the tube 25-1 is abolished.

尚、その他の構成は図１の実施形態と同様であるので、同一のものには同一符号を付してそれらの説明は省略する。   Since other configurations are the same as those of the embodiment of FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted.

而して、本実施形態に係るＥＧＲクーラー４５によっても、却水導入パイプ３３から流入した冷却水Ｗは、エンドプレート３７に沿って流れ難く、領域Ａに冷却水Ｗの澱みが生じるが、本実施形態は、主冷却水流路Ｗ１中のチューブ２５-1の部位に突起４３を設けて、主冷却水流路Ｗ１から外れて冷却水流れの澱みが発生する領域Ａでのチューブ２５-1の突起４３を廃止したため、図３の従来例に比し領域Ａでのチューブ２５-1の熱交換効率が低下し、この結果、単位水当たりの仕事量（熱交換量）が低下（冷却水流量に対する負荷が低減）することとなる。   Thus, even with the EGR cooler 45 according to the present embodiment, the cooling water W flowing from the rejection water introduction pipe 33 is difficult to flow along the end plate 37, and the stagnation of the cooling water W occurs in the region A. In the embodiment, a protrusion 43 is provided at a portion of the tube 25-1 in the main cooling water flow path W1, and the protrusion of the tube 25-1 in the region A where the stagnation of the cooling water flow occurs outside the main cooling water flow path W1. 43 has been abolished, the heat exchange efficiency of the tube 25-1 in the region A is lower than that in the conventional example of FIG. 3, and as a result, the work amount (heat exchange amount) per unit water is reduced (with respect to the cooling water flow rate). The load will be reduced).

従って、本実施形態によっても、図１のＥＧＲクーラー４１と同様、ＥＧＲガス入口側のエンドプレート３７に沿った領域Ａでの冷却水流れの澱みによる核沸騰が抑制でき、この結果、核沸騰に起因する２次不具合（チューブ２５とエンドプレート３７との接合部の亀裂）の危険性を軽減することが可能となって、ＥＧＲ装置の耐久信頼性の向上が図れる利点を有する。   Therefore, also in this embodiment, nucleate boiling due to stagnation of the cooling water flow in the region A along the end plate 37 on the EGR gas inlet side can be suppressed, similarly to the EGR cooler 41 of FIG. It is possible to reduce the risk of secondary defects (cracking at the joint between the tube 25 and the end plate 37) due to the advantage that durability reliability of the EGR device can be improved.

尚、既述した各実施形態は、冷却水ＷとＥＧＲガスＧとの熱交換効率を高める手段として、チューブ２５，２５-1内面に突出する突起４３を用いたが、斯かる突起４３に代え、チューブの外周に冷却フィンを設けて、これを熱交換効率を高める手段としてもよい。   In each of the above-described embodiments, the protrusions 43 protruding from the inner surfaces of the tubes 25 and 25-1 are used as means for increasing the heat exchange efficiency between the cooling water W and the EGR gas G. A cooling fin may be provided on the outer periphery of the tube, and this may be used as a means for increasing the heat exchange efficiency.

請求項１及び請求項３の一実施形態に係るＥＧＲクーラーの概略断面図である。It is a schematic sectional drawing of the EGR cooler which concerns on one Embodiment of Claim 1 and Claim 3. 請求項２及び請求項３の一実施形態に係るＥＧＲクーラーの概略断面図である。It is a schematic sectional drawing of the EGR cooler which concerns on one Embodiment of Claim 2 and Claim 3. 従来のＥＧＲクーラーの概略断面図である。It is a schematic sectional drawing of the conventional EGR cooler.

符号の説明Explanation of symbols

２３ シェル
２５，２５-1 チューブ
２７，２９ ディフューザ
３３ 冷却水導入パイプ
３５ 冷却水導出パイプ
３７，３９ エンドプレート
４１，４５ ＥＧＲクーラー
４３ 突起
23 Shell 25, 25-1 Tube 27, 29 Diffuser 33 Cooling water introduction pipe 35 Cooling water outlet pipe 37, 39 End plate 41, 45 EGR cooler 43 Projection

Claims (4)

筒状のシェルの両端部に、ディフューザを介してＥＧＲガス導入パイプとＥＧＲガス導出パイプを接続し、
シェルの両端部を閉塞するエンドプレート間に、ディフューザ内に開口する複数のチューブを挿着すると共に、
ＥＧＲガス導入パイプ側のシェルの周壁に冷却水導入パイプを接続し、ＥＧＲガス導出パイプ側のシェルの周壁に冷却水導出パイプを接続したＥＧＲクーラーに於て、
ＥＧＲガス入口側を除いて前記チューブに、冷却水とＥＧＲガスとの熱交換効率を高める手段を施したことを特徴とするＥＧＲクーラー。 An EGR gas introduction pipe and an EGR gas outlet pipe are connected to both ends of the cylindrical shell through a diffuser,
Between the end plates that close both ends of the shell, insert a plurality of tubes that open in the diffuser,
In the EGR cooler in which the cooling water introduction pipe is connected to the peripheral wall of the shell on the EGR gas introduction pipe side, and the cooling water extraction pipe is connected to the peripheral wall of the shell on the EGR gas extraction pipe side.
An EGR cooler characterized in that means other than the EGR gas inlet side is provided with means for increasing heat exchange efficiency between cooling water and EGR gas. 筒状のシェルの両端部に、ディフューザを介してＥＧＲガス導入パイプとＥＧＲガス導出パイプを接続し、
シェルの両端部を閉塞するエンドプレート間に、ディフューザ内に開口する複数のチューブを挿着すると共に、
ＥＧＲガス導入パイプ側のシェルの周壁に冷却水導入パイプを接続し、ＥＧＲガス導出パイプ側のシェルの周壁に冷却水導出パイプを接続したＥＧＲクーラーに於て、
前記冷却水導入パイプから冷却水導出パイプに亘ってシェル内に形成される冷却水の主冷却水流路中のチューブの部位に、冷却水とＥＧＲガスとの熱交換効率を高める手段を施したことを特徴とするＥＧＲクーラー。 An EGR gas introduction pipe and an EGR gas outlet pipe are connected to both ends of the cylindrical shell through a diffuser,
Between the end plates that close both ends of the shell, insert a plurality of tubes that open in the diffuser,
In the EGR cooler in which the cooling water introduction pipe is connected to the peripheral wall of the shell on the EGR gas introduction pipe side, and the cooling water extraction pipe is connected to the peripheral wall of the shell on the EGR gas extraction pipe side.
A means for increasing the heat exchange efficiency between the cooling water and the EGR gas has been applied to the tube portion in the main cooling water flow path of the cooling water formed in the shell from the cooling water introduction pipe to the cooling water outlet pipe. EGR cooler characterized by 冷却水とＥＧＲガスとの熱交換効率を高める手段は、チューブ内面に突出する複数の突起であることを特徴とする請求項１または請求項２に記載のＥＧＲクーラー。   3. The EGR cooler according to claim 1, wherein the means for increasing the heat exchange efficiency between the cooling water and the EGR gas is a plurality of protrusions protruding on the inner surface of the tube. 4. 冷却水とＥＧＲガスとの熱交換効率を高める手段は、チューブの外周に設けた冷却フィンであることを特徴とする請求項１または請求項２に記載のＥＧＲクーラー。
3. The EGR cooler according to claim 1, wherein the means for increasing the heat exchange efficiency between the cooling water and the EGR gas is a cooling fin provided on an outer periphery of the tube.
JP2007166271A 2007-06-25 2007-06-25 Egr cooler Pending JP2009002300A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014181855A (en) * 2013-03-19 2014-09-29 T Rad Co Ltd Header plate-less heat exchanger
JP5747335B2 (en) * 2011-01-11 2015-07-15 国立大学法人 東京大学 Heat exchanger for heat engine
JP2019120162A (en) * 2017-12-28 2019-07-22 株式会社クボタ Egr-equipped engine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1113551A (en) * 1997-06-23 1999-01-19 Isuzu Motors Ltd Egr cooler
JP2000130964A (en) * 1998-10-26 2000-05-12 Toyota Motor Corp Double-pipe heat exchanger
JP2004346919A (en) * 2003-05-26 2004-12-09 Nissan Diesel Motor Co Ltd Egr cooler

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1113551A (en) * 1997-06-23 1999-01-19 Isuzu Motors Ltd Egr cooler
JP2000130964A (en) * 1998-10-26 2000-05-12 Toyota Motor Corp Double-pipe heat exchanger
JP2004346919A (en) * 2003-05-26 2004-12-09 Nissan Diesel Motor Co Ltd Egr cooler

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5747335B2 (en) * 2011-01-11 2015-07-15 国立大学法人 東京大学 Heat exchanger for heat engine
JP2014181855A (en) * 2013-03-19 2014-09-29 T Rad Co Ltd Header plate-less heat exchanger
JP2019120162A (en) * 2017-12-28 2019-07-22 株式会社クボタ Egr-equipped engine

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