JP2006132470A - Egr device - Google Patents

Egr device Download PDF

Info

Publication number
JP2006132470A
JP2006132470A JP2004323967A JP2004323967A JP2006132470A JP 2006132470 A JP2006132470 A JP 2006132470A JP 2004323967 A JP2004323967 A JP 2004323967A JP 2004323967 A JP2004323967 A JP 2004323967A JP 2006132470 A JP2006132470 A JP 2006132470A
Authority
JP
Japan
Prior art keywords
egr
cooler
water
cooled
passage
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.)
Pending
Application number
JP2004323967A
Other languages
Japanese (ja)
Inventor
Toshiharu Otsubo
要春 大坪
英行 ▲高▼橋
Hideyuki Takahashi
Yoshihisa Yamaki
芳久 山木
Koichi Hirota
浩一 広田
Kei Ishiwatari
圭 石渡
Eiichi Hiruma
栄一 昼間
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.)
Mitsubishi Fuso Truck and Bus Corp
Original Assignee
Mitsubishi Fuso Truck and Bus Corp
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 Mitsubishi Fuso Truck and Bus Corp filed Critical Mitsubishi Fuso Truck and Bus Corp
Priority to JP2004323967A priority Critical patent/JP2006132470A/en
Publication of JP2006132470A publication Critical patent/JP2006132470A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0001—Recuperative heat exchangers
    • F28D21/0003—Recuperative heat exchangers the heat being recuperated from exhaust gases
    • 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

  • Exhaust-Gas Circulating Devices (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR device capable of securing heat exchange amount by making an EGR cooler cooling EGR gas have a water-cooling two-stage type cooler structure and of suppressing decline in temperature efficiency caused by adherence of PM in the EGR gas to inside of the cooler. <P>SOLUTION: The EGR device is provide with an EGR passage 2 connecting an exhaust passage of an engine with an intake passage; a first water-cooling type EGR cooler 3 interposed on an exhaust gas flow upstream side of the EGR passage 2; and a second water-cooling type EGR cooler 4 interposed on the EGR passage 2 in the downstream side of the first water-cooling type EGR cooler 3. Sufficient pre-cooling of EGR gas is performed by the first water-cooling type EGR cooler 3, and deterioration of the temperature efficiency of the cooler is suppressed by suppressing PM amount moved/adhered from the EGR gas side to a cooler inner wall face by thermal diffusion by the second water-cooling type EGR cooler 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、エンジンから排出される排気ガスの一部を吸気系に還流するＥＧＲ装置に関する。   The present invention relates to an EGR device that recirculates part of exhaust gas discharged from an engine to an intake system.

車両のエンジンは、ＥＧＲ装置によりエンジンから排出される排気ガスの一部（以下「ＥＧＲガス」という）を吸気系に還流して燃焼を緩慢にし、燃焼温度を下げてＮＯｘの低減を図るようにしている。排気系から排出された排気ガスは高温であり、このままでは単位体積当たりのガス濃度が減少して所望のＥＧＲ量を導入することができないと共に導入したＥＧＲガスの熱により吸気温度が上昇して吸気効率が低下するおそれがある。このため、ＥＧＲクーラによりＥＧＲガスを冷却するようにしている。   The vehicle engine is designed to reduce the NOx by lowering the combustion temperature by slowing the combustion by returning a part of the exhaust gas (hereinafter referred to as “EGR gas”) discharged from the engine by the EGR device to the intake system. ing. The exhaust gas discharged from the exhaust system is at a high temperature. If the exhaust gas is left as it is, the gas concentration per unit volume decreases and the desired amount of EGR cannot be introduced, and the intake air temperature rises due to the heat of the introduced EGR gas and the intake air Efficiency may be reduced. For this reason, the EGR gas is cooled by the EGR cooler.

水冷式エンジンに採用されているＥＧＲクーラは、一般に冷媒としてエンジン冷却水を利用している。そして、エンジン冷却系の負荷を増大することなくＥＧＲガスを効率よく冷却できるＥＧＲクーラとして、排気系から水冷式ＥＧＲクーラに至るＥＧＲパイプの少なくとも一部を、外周又は内周の少なくとも一方にフィンを設け、水冷式ＥＧＲクーラに供給されるＥＧＲガスを空冷フィン付パイプで外気で予冷してクーラ全体としての冷却容量を大きくした２段式のＥＧＲクーラが提案されている（例えば、特許文献１参照）。
特開２００３−１６１２０９号公報 An EGR cooler employed in a water-cooled engine generally uses engine cooling water as a refrigerant. As an EGR cooler that can efficiently cool EGR gas without increasing the load of the engine cooling system, at least a part of the EGR pipe from the exhaust system to the water-cooled EGR cooler is provided with fins on at least one of the outer periphery and the inner periphery. A two-stage EGR cooler has been proposed in which EGR gas supplied to a water-cooled EGR cooler is precooled with outside air using a pipe with air-cooling fins to increase the cooling capacity of the entire cooler (see, for example, Patent Document 1). ).
JP 2003-161209 A

しかしながら、上記２段式ＥＧＲクーラの予冷部分としている空冷フィン付パイプは、冷却温度効率が後段に控えた水冷式ＥＧＲクーラに比して桁違いに低いために有効な熱交換量を得ることができず、クーラ全体としての冷却容量を大きくすることは困難であり、提案されているような効果を期待することはできない。
また、前段の空冷フィン付クーラの予冷温度効率が低いと、後段の水冷式クーラの冷却水温度に対してＥＧＲガスの温度が高いために温度差に起因して水冷式クーラの内壁面にＥＧＲガス中の粒子状物質（以下「ＰＭ」という）が付着しやすくなる。そして、水冷式クーラの内壁面にＰＭが付着して堆積すると、クーラの温度効率が著しく低下するという問題もある。 However, the air-cooled finned pipe as the pre-cooling part of the two-stage EGR cooler has an order of magnitude lower cooling efficiency than the water-cooled EGR cooler with a subsequent stage, so that an effective heat exchange amount can be obtained. Therefore, it is difficult to increase the cooling capacity of the whole cooler, and the proposed effect cannot be expected.
In addition, if the precooling temperature efficiency of the air-cooled fin cooler at the front stage is low, the temperature of the EGR gas is higher than the cooling water temperature of the water-cooled cooler at the rear stage. Particulate matter in gas (hereinafter referred to as “PM”) tends to adhere. And when PM adheres and accumulates on the inner wall surface of a water-cooled cooler, there is also a problem that the temperature efficiency of the cooler is significantly lowered.

本発明は、上述の点に鑑みてなされたもので、ＥＧＲガスを冷却するＥＧＲクーラを、水冷２段式クーラ構造として熱交換量を確保すると共にＥＧＲガス中のＰＭがクーラ内部に付着することによる温度効率の低下を抑制するようにしたＥＧＲ装置を提供することを目的とする。   The present invention has been made in view of the above points. The EGR cooler that cools the EGR gas has a water-cooled two-stage cooler structure, and the heat exchange amount is secured and PM in the EGR gas adheres to the inside of the cooler. An object of the present invention is to provide an EGR device that suppresses a decrease in temperature efficiency due to the above.

上記目的を達成するために請求項１のＥＧＲ装置は、エンジンの排気通路と吸気通路とを接続するＥＧＲ通路と、前記ＥＧＲ通路の排気流れ上流側に介挿された第１の水冷式ＥＧＲクーラと、前記第１の水冷式ＥＧＲクーラの下流のＥＧＲ通路に介装された第２の水冷式ＥＧＲクーラとを備えた構成としている。
エンジンの排気通路に排出された排気ガスの一部がＥＧＲ通路を通してエンジンの吸気通路に還流される。ＥＧＲ通路に導入された高温のＥＧＲガスは、前段の第１の水冷式ＥＧＲクーラにより冷却された後、更に後段の第２の水冷式ＥＧＲクーラにより冷却される。ＥＧＲガスは、前段の第１の水冷式ＥＧＲクーラにより充分に予冷されることで、後段の第２の水冷式ＥＧＲクーラで熱拡散によりＥＧＲガス側からクーラ内壁面へ移動・付着するＰＭの量が抑制され、クーラの温度効率の劣化が抑制される。また、ＥＧＲガスが充分に冷却されることで、単位体積当たりのガス濃度の減少が防止され、所望のＥＧＲ量を導入することができる共に、導入したＥＧＲガスによる吸気温度の上昇が抑制されて吸気効率の低下が防止される。 In order to achieve the above object, an EGR apparatus according to claim 1 includes an EGR passage connecting an exhaust passage and an intake passage of an engine, and a first water-cooled EGR cooler inserted on the exhaust flow upstream side of the EGR passage. And a second water-cooled EGR cooler interposed in the EGR passage downstream of the first water-cooled EGR cooler.
A part of the exhaust gas discharged to the engine exhaust passage is returned to the engine intake passage through the EGR passage. The high-temperature EGR gas introduced into the EGR passage is cooled by the first water-cooled EGR cooler at the front stage and then cooled by the second water-cooled EGR cooler at the rear stage. EGR gas is sufficiently pre-cooled by the first water-cooled EGR cooler at the front stage, and the amount of PM that moves and adheres from the EGR gas side to the cooler inner wall surface by thermal diffusion in the second water-cooled EGR cooler at the rear stage. And the deterioration of the temperature efficiency of the cooler is suppressed. In addition, since the EGR gas is sufficiently cooled, a decrease in gas concentration per unit volume can be prevented, a desired EGR amount can be introduced, and an increase in intake air temperature due to the introduced EGR gas is suppressed. A reduction in intake efficiency is prevented.

請求項２のＥＧＲ装置は、請求項１において、前記第１の水冷式ＥＧＲクーラを多管式クーラにより構成し、前記第２の水冷式ＥＧＲクーラを多段式積層型のフィン式クーラにより構成したものである。
ＥＧＲ通路内を流れる高温のＥＧＲガスに直接晒される前段の第１の水冷式ＥＧＲクーラに多管式クーラを採用することで、ＰＭによる目詰まりがし難く、高温のＥＧＲガスを充分に予冷することができる。この多管式クーラで予冷してＰＭ付着をできるだけ抑制した後、低温化されてＰＭ付着が抑制できている後段の第２の水冷式ＥＧＲクーラを温度効率の高い打段積層型のフィン式クーラにより冷却する。これにより、ＰＭ付着が抑えられたバランスのよい冷却システムが構築される。 The EGR device according to claim 2 is the EGR device according to claim 1, wherein the first water-cooled EGR cooler is configured by a multi-tube cooler, and the second water-cooled EGR cooler is configured by a multistage stacked fin-type cooler. Is.
By adopting a multi-tube cooler for the first water-cooled EGR cooler that is directly exposed to the high-temperature EGR gas flowing in the EGR passage, clogging due to PM is difficult to occur, and the high-temperature EGR gas is sufficiently pre-cooled. be able to. This multitubular cooler is precooled to suppress PM adhesion as much as possible, and then the second water-cooled EGR cooler in the latter stage, which has been lowered in temperature and suppressed PM adhesion, is replaced with a temperature-efficient step-stacked fin-type cooler. To cool. As a result, a well-balanced cooling system in which PM adhesion is suppressed is constructed.

請求項３のＥＧＲ装置は、請求項１又は２において、前記第１の水冷式ＥＧＲクーラの排気ガス通路壁に煤の付着を抑制する付着抑制剤がコーティングされている構成としたものである。
第１の水冷式ＥＧＲクーラのＥＧＲガス通路の内壁面にコーティングされている付着抑制剤により、ＥＧＲガス中の煤（ＰＭ）の付着が抑制され、クーラ温度効率の低下が抑制される。 According to a third aspect of the present invention, there is provided an EGR apparatus according to the first or second aspect, wherein the exhaust gas passage wall of the first water-cooled EGR cooler is coated with an adhesion inhibitor that suppresses adhesion of soot.
By the adhesion inhibitor coated on the inner wall surface of the EGR gas passage of the first water-cooled EGR cooler, adhesion of soot (PM) in the EGR gas is suppressed, and a decrease in cooler temperature efficiency is suppressed.

請求項１のＥＧＲ装置によれば、水冷２段クーラ構造とすることで前段の第１の水冷式ＥＧＲクーラで高温のＥＧＲガスを充分に予冷することができ、後段の第２の水冷式ＥＧＲクーラで熱拡散によりＥＧＲガス側からクーラ内壁面へ移動・付着するＰＭの量が抑制され、クーラの温度効率の劣化が抑制される。
また、クーラの温度効率が安定して劣化によりサチュレートする温度効率と、初期温度効率がかけ離れていないために、サチュレート後高効率を維持したい場合などに、初期効率が高すぎてＥＧＲ冷却水が沸騰する症状を緩和することができる。 According to the EGR apparatus of the first aspect, the water-cooled two-stage cooler structure can sufficiently pre-cool the high-temperature EGR gas with the first water-cooled EGR cooler at the front stage, and the second water-cooled EGR at the rear stage. The amount of PM that moves and adheres from the EGR gas side to the cooler inner wall surface due to thermal diffusion in the cooler is suppressed, and deterioration of the temperature efficiency of the cooler is suppressed.
Also, because the temperature efficiency of the cooler is stable and saturates due to deterioration, and the initial temperature efficiency is not far apart, if you want to maintain high efficiency after saturating, the initial efficiency is too high and the EGR cooling water boils Can relieve symptoms.

また、ＥＧＲガスが充分に冷却されることで、所望のＥＧＲ量を導入することができると共に導入したＥＧＲガスによる吸気温度の上昇が抑制されて吸気効率の低下が防止される。
請求項２のＥＧＲ装置によれば、高温のＥＧＲガスに直接晒される前段の第１の水冷式ＥＧＲクーラに多管式クーラを採用することで、ＰＭによる目詰まりがし難く、高温のＥＧＲガスを充分に予冷することができる。そして、多管式クーラで予冷してＰＭ付着をできるだけ抑制した後、低温化されてＰＭ付着が抑制できている後段の第２の水冷式ＥＧＲクーラを温度効率の高い打段積層型のフィン式クーラにより冷却することにより、ＰＭ付着が抑えられたバランスのよい冷却システムを構築することができる。 In addition, when the EGR gas is sufficiently cooled, a desired EGR amount can be introduced, and an increase in the intake air temperature due to the introduced EGR gas is suppressed, thereby preventing a reduction in intake efficiency.
According to the EGR apparatus of claim 2, by adopting a multi-tubular cooler for the first water-cooled EGR cooler that is directly exposed to high-temperature EGR gas, clogging due to PM is difficult to occur, and high-temperature EGR gas is used. Can be sufficiently pre-cooled. Then, after pre-cooling with a multi-tube cooler to suppress PM adhesion as much as possible, the second water-cooled EGR cooler at the latter stage, which has been reduced in temperature and suppressed PM adhesion, is replaced with a temperature-efficient step-stacked fin type By cooling with a cooler, a well-balanced cooling system in which PM adhesion is suppressed can be constructed.

請求項３のＥＧＲ装置によれば、第１の水冷式ＥＧＲクーラのＥＧＲガス通路の内壁面にコーティングされている付着抑制剤により、ＥＧＲガス中の煤（ＰＭ）の付着が抑制され、クーラ温度効率の低下が抑制される。   According to the EGR device of claim 3, the adhesion inhibitor coated on the inner wall surface of the EGR gas passage of the first water-cooled EGR cooler suppresses the adhesion of soot (PM) in the EGR gas, and the cooler temperature. Reduction in efficiency is suppressed.

以下、本発明の実施形態を図面により詳細に説明する。
図１は、本発明に係るＥＧＲ装置のＥＧＲガス冷却部の構成を示す断面図で、ＥＧＲガス冷却部１は、水冷２段クーラ構造とされ、ＥＧＲガス通路としてのＥＧＲパイプ２に第１の水冷式ＥＧＲクーラ３、第２の水冷式ＥＧＲクーラ４が間隔を存して介挿されて構成されている。ＥＧＲパイプ２は、図中右側がエンジンの排気通路に接続されて上流側とされ、図中左側が前記エンジンの吸気通路（何れも図示せず）に接続されて下流側とされている。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration of an EGR gas cooling unit of an EGR apparatus according to the present invention. The EGR gas cooling unit 1 has a water-cooled two-stage cooler structure, and a first EGR pipe 2 serving as an EGR gas passage is connected to a first A water-cooled EGR cooler 3 and a second water-cooled EGR cooler 4 are inserted with a gap therebetween. The right side of the EGR pipe 2 is connected to the exhaust passage of the engine to be the upstream side, and the left side of the EGR pipe 2 is connected to the intake passage (none of which is shown) of the engine to be the downstream side.

ＥＧＲパイプ２の上流側に配置されている前段の第１の水冷式ＥＧＲクーラ３は、構造が簡単な多管（チューブ）式クーラが使用され、第１の水冷式ＥＧＲクーラ３の下流側に配置されている後段の第２の水冷式ＥＧＲクーラ４は、温度効率の高い多段積層型のプレートフィン式クーラが使用されている。
第１の水冷式ＥＧＲクーラ３は、図１及び図２に示すように大径の円筒状のケース５内に当該ケース５の軸方向に沿ってＥＧＲガス通路としての小径のパイプ６が多数間隔を存して且つ軸方向に平行に配列して収納され、両端が隔壁７、７に穿設された穴に液密に嵌合固定されており、これらの隔壁７の外周部がケース５の内周面に全周に亘り液密に固定されている。 The first water-cooled EGR cooler 3 disposed on the upstream side of the EGR pipe 2 uses a multi-tube (tube) cooler with a simple structure, and is located downstream of the first water-cooled EGR cooler 3. The arranged second water-cooled EGR cooler 4 is a multi-stage plate fin type cooler with high temperature efficiency.
The first water-cooled EGR cooler 3 includes a large number of small-diameter pipes 6 as EGR gas passages in the large-diameter cylindrical case 5 along the axial direction of the case 5 as shown in FIGS. 1 and 2. And both ends of the partition walls 7 and 7 are fixed in a liquid-tight manner in holes formed in the partition walls 7, 7. It is liquid-tightly fixed to the inner peripheral surface over the entire circumference.

そして、ケース５の内周面と両端の隔壁７、７とによりパイプ６の外周面を取り囲むように冷却水通路８が画成されている。ケース５は、両端部がテーパ状に縮径されてＥＧＲガスの入口５ａ、出口５ｂとされ、ＥＧＲパイプ２の上流側に介挿されている。また、ケース５の冷却水通路８の上流側に冷却水入口５ｃが、下流側に冷却水出口５ｄが設けられている。これらのケース５、パイプ６及び隔壁７は、耐食性に優れたステンレス鋼板により形成されている。   A cooling water passage 8 is defined by the inner peripheral surface of the case 5 and the partition walls 7 and 7 at both ends so as to surround the outer peripheral surface of the pipe 6. Both ends of the case 5 are tapered to form EGR gas inlets 5 a and outlets 5 b, and are inserted upstream of the EGR pipe 2. A cooling water inlet 5c is provided on the upstream side of the cooling water passage 8 of the case 5 and a cooling water outlet 5d is provided on the downstream side. The case 5, the pipe 6 and the partition wall 7 are formed of a stainless steel plate having excellent corrosion resistance.

そして、ＥＧＲガス通路としてのパイプ６の内壁面にＥＧＲガス中に含まれるＰＭの付着を抑制するための表面処理が施されている。このＰＭ付着抑制表面処理は、例えば、酸化珪素（ＳｉＯ2）ガラス被膜をコーティング処理する。
第２の水冷式ＥＧＲクーラ４は、箱形のケース１１内に平板１２を間隔を存して対向させて配置して、冷却水通路１３とＥＧＲガス通路１４とから成る一組の熱交換器（以下「コア」という）１５を形成し、このコア１５を多段に積層して構成されている。ＥＧＲガス通路１３の内部には、図３に示すように冷却効率を高めるために冷却フィン１６がへＥＧＲガス通路１３の全幅、全長に亘り設けられている。 And the surface treatment for suppressing adhesion of PM contained in EGR gas is given to the inner wall surface of the pipe 6 as an EGR gas passage. In this PM adhesion suppressing surface treatment, for example, a silicon oxide (SiO 2 ) glass film is coated.
The second water-cooled EGR cooler 4 is a set of heat exchangers comprising a cooling water passage 13 and an EGR gas passage 14 in which a flat plate 12 is disposed in a box-shaped case 11 with a space therebetween. (Hereinafter referred to as “core”) 15 is formed, and the core 15 is laminated in multiple stages. Inside the EGR gas passage 13, as shown in FIG. 3, cooling fins 16 are provided over the entire width and length of the EGR gas passage 13 in order to increase the cooling efficiency.

各コア１５のＥＧＲガス通路１４は、両端がケース１１の両端部に向かって開口されており、これら両端部は、縮径されてＥＧＲガスの入口１１ａ及び出口１１ｂとされて第１の水冷式ＥＧＲクーラ３の下流側のＥＧＲパイプ２に介挿されている。各コア１５の冷却水通路１３は、両端が連通されており、ケース１１の冷却水通路１３の上流側に冷却水入口１１ｃが、下流側に冷却水出口１１ｄが設けられている。これらのケース１１、平板１２、冷却フィン１６は、耐食性に優れたステンレス鋼板により形成されている。   Both ends of the EGR gas passage 14 of each core 15 are open toward both ends of the case 11, and both the end portions are reduced in diameter to serve as an EGR gas inlet 11a and outlet 11b. It is inserted in the EGR pipe 2 on the downstream side of the EGR cooler 3. Both ends of the cooling water passage 13 of each core 15 communicate with each other, and a cooling water inlet 11 c is provided on the upstream side of the cooling water passage 13 of the case 11, and a cooling water outlet 11 d is provided on the downstream side. The case 11, the flat plate 12, and the cooling fin 16 are formed of a stainless steel plate having excellent corrosion resistance.

第１の水冷式ＥＧＲクーラ３の冷却水出口５ｄと第２の水冷式ＥＧＲクーラ４の冷却水入口１１ｃは、冷却水パイプ１７により接続されており、第１の水冷式ＥＧＲクーラ３の冷却水入口５ｃ、第２の水冷式ＥＧＲクーラ４の冷却水出口１１ｄは、冷却水パイプ１８、１９により冷却水循環通路（図示せず）に接続されている。
以下に作用を説明する。 The cooling water outlet 5d of the first water-cooled EGR cooler 3 and the cooling water inlet 11c of the second water-cooled EGR cooler 4 are connected by a cooling water pipe 17, and the cooling water of the first water-cooled EGR cooler 3 is connected. The inlet 5c and the cooling water outlet 11d of the second water-cooled EGR cooler 4 are connected to a cooling water circulation passage (not shown) by cooling water pipes 18 and 19.
The operation will be described below.

図１に示すようにエンジンの排気通路に排出された排気ガスの一部がＥＧＲガスとしてＥＧＲパイプ２に導入され、第１の水冷式ＥＧＲクーラ３の各パイプ６内を通り出口５ｂからＥＧＲパイプ２に吐出される。一方、ＥＧＲ冷却水は、冷却水循環通路の冷却水パイプ１８から第１の水冷式ＥＧＲクーラ３の冷却水通路８に導入され、各パイプ６内を通る高温のＥＧＲガスを冷却し、冷却水出口５ｄから冷却水パイプ１７に吐出される。   As shown in FIG. 1, a part of the exhaust gas discharged into the exhaust passage of the engine is introduced into the EGR pipe 2 as EGR gas, passes through each pipe 6 of the first water-cooled EGR cooler 3, and exits from the outlet 5b. 2 is discharged. On the other hand, the EGR cooling water is introduced into the cooling water passage 8 of the first water-cooled EGR cooler 3 from the cooling water pipe 18 of the cooling water circulation passage, cools the high-temperature EGR gas passing through each pipe 6, and exits the cooling water. It is discharged from 5d to the cooling water pipe 17.

第１の水冷式ＥＧＲクーラ３により冷却されて温度が低下したＥＧＲガスは、第２の水冷式ＥＧＲクーラ４に導入され、各ＥＧＲガス通路１４内を通り、出口１１ｂからＥＧＲパイプ２の下流側に吐出される。一方、第１の水冷式ＥＧＲクーラ３から吐出された冷却水は、冷却水パイプ１７から第２の水冷式ＥＧＲクーラ４の各冷却水通路１３に導入され、各ＥＧＲガス通路１４内を通るＥＧＲガスを更に冷却し、冷却水出口１１ｄから冷却水パイプ１９に吐出されて前記冷却水循環通路に還流される。   The EGR gas cooled by the first water-cooled EGR cooler 3 and lowered in temperature is introduced into the second water-cooled EGR cooler 4, passes through each EGR gas passage 14, and is downstream of the EGR pipe 2 from the outlet 11 b. Discharged. On the other hand, the cooling water discharged from the first water-cooled EGR cooler 3 is introduced from the cooling water pipe 17 into each cooling water passage 13 of the second water-cooled EGR cooler 4 and passes through each EGR gas passage 14. The gas is further cooled, discharged from the cooling water outlet 11d to the cooling water pipe 19, and returned to the cooling water circulation passage.

ＥＧＲパイプ２の上流側に配置された前段の第１の水冷式ＥＧＲクーラ３により高温のＥＧＲを充分に予冷した後、後段の第２の水冷式ＥＧＲクーラ４で更に冷却する際に熱拡散によりＥＧＲガス側からＥＧＲガス通路１４の内壁面及びフィン１６の表面に移動・付着するＰＭの量を抑えることができる。
また、ＥＧＲガス冷却部１を水冷２段クーラ構造とすることで、１段当たりの温度効率が低くても全体の温度効率を容易に高くすることができることから、直接高温に晒される前段の第１の水冷式ＥＧＲクーラ３に低温度効率ながら目詰まりし難い構造が簡単な多管式クーラを採用し、当該第１の水冷式ＥＧＲクーラ３でＥＧＲガス中に含まれるＰＭの付着をできるだけ抑制した上で、低温化されＰＭ付着が抑制されている後段の第２の水冷式ＥＧＲクーラ４を温度効率を重視した多段積層型のプレートフィン式クーラとすることで、前段・後段ともＰＭ付着が抑えられたバランスのよい冷却システムを構築することができる。 The high temperature EGR is sufficiently pre-cooled by the first water-cooled EGR cooler 3 disposed upstream of the EGR pipe 2 and then further cooled by the second water-cooled EGR cooler 4 in the subsequent stage. The amount of PM that moves and adheres to the inner wall surface of the EGR gas passage 14 and the surface of the fin 16 from the EGR gas side can be suppressed.
In addition, since the EGR gas cooling section 1 has a water-cooled two-stage cooler structure, the overall temperature efficiency can be easily increased even if the temperature efficiency per stage is low. The 1 water-cooled EGR cooler 3 employs a multi-tube cooler with a low temperature efficiency and a structure that is not easily clogged, and the first water-cooled EGR cooler 3 suppresses the adhesion of PM contained in the EGR gas as much as possible. In addition, the second water-cooled EGR cooler 4 in the subsequent stage, which has been reduced in temperature and suppressed in PM adhesion, is a multi-stage stacked plate fin type cooler that emphasizes temperature efficiency, so that PM adhesion can be achieved in both the front and rear stages. A well-balanced cooling system that is suppressed can be constructed.

更に、前段の第１の水冷式ＥＧＲクーラ３のＥＧＲガス通路としてのパイプ６の内壁面にＰＭ付着を抑制する表面処理を施すことにより、付着したＰＭの剥離が促進されて長期間に亘りＰＭ付着量を少なく抑えることが可能となる。チューブ６の内壁面に付着したＰＭは、エンジン停止後冷却水の温度が低下し、これに伴いチューブ６の温度が低下した際の収縮等により剥離される。   Furthermore, by applying a surface treatment that suppresses PM adhesion to the inner wall surface of the pipe 6 as the EGR gas passage of the first water-cooled EGR cooler 3 in the previous stage, peeling of the adhering PM is promoted and PM is maintained for a long period of time. It is possible to reduce the amount of adhesion. The PM adhering to the inner wall surface of the tube 6 is peeled off by contraction or the like when the temperature of the cooling water decreases after the engine stops and the temperature of the tube 6 decreases accordingly.

更に、ＥＧＲパイプ２に前段の第１の水冷式ＥＧＲクーラ３と後段の第２の水冷式ＥＧＲクーラ４とを間隔を存して配置した水冷２段構成とすることにより、ＥＧＲガスと冷却水との隔壁が一旦分離でき、熱伝達による隔壁上流側から下流側への熱移動経路を遮断できるため、遮断していない場合に対し隔壁下流側の温度を低く抑えることができる。この結果、単に冷却式ＥＧＲクーラを１段として長い形状の構成とした場合に比してＥＧＲガスの温度効率の大幅な向上が図られる。   Further, the EGR pipe 2 has a water-cooled two-stage configuration in which the first water-cooled EGR cooler 3 in the front stage and the second water-cooled EGR cooler 4 in the rear stage are arranged with an interval therebetween, so that EGR gas and cooling water can be obtained. Can be separated once, and the heat transfer path from the upstream side to the downstream side of the partition wall by heat transfer can be shut off, so that the temperature on the downstream side of the partition wall can be kept low compared to the case where the partition wall is not shut off. As a result, the temperature efficiency of the EGR gas can be greatly improved as compared with the case where the cooling type EGR cooler is simply configured as one stage and has a long shape.

図４は、ＥＧＲパイプに水冷式ＥＧＲクーラを１段設けた場合と、本願発明の水冷式ＥＧＲクーラを２段設けた構造における運転期間とクーラ温度効率との関係の一例を示す。図４において曲線Ｉは、水冷式ＥＧＲクーラを１段設けた場合を示し、運転期間と共にクーラ温度効率が急激に低下している。
これに対して本願発明のように水冷式ＥＧＲクーラを２段設けた場合には、曲線II、IIIで示すようにクーラ温度効率の低下が大幅に抑制される。曲線IIは、前段の第１の水冷式ＥＧＲクーラ３に多管式クーラを、後段の第２の水冷式ＥＧＲクーラ４に多段積層型のプレートフィン式クーラを使用し、且つ第１の水冷式ＥＧＲクーラ３のパイプ６の内壁面にＰＭ付着抑制コーティングを施さない場合を示し、曲線IIIは、第１の水冷式ＥＧＲクーラ４のパイプ６の内壁面にＰＭ付着抑制コーティングを施した場合を示す。 FIG. 4 shows an example of the relationship between the operation period and the cooler temperature efficiency in the case where one stage of the water-cooled EGR cooler is provided in the EGR pipe and in the structure in which the two stages of the water-cooled EGR cooler of the present invention are provided. In FIG. 4, a curve I shows a case where one stage of the water-cooled EGR cooler is provided, and the cooler temperature efficiency rapidly decreases with the operation period.
On the other hand, when two stages of water-cooled EGR coolers are provided as in the present invention, a decrease in cooler temperature efficiency is greatly suppressed as shown by curves II and III. Curve II shows that the first water-cooled EGR cooler 3 at the front stage uses a multi-tube cooler, the second water-cooled EGR cooler 4 at the rear stage uses a multi-stage stacked plate fin cooler, and the first water-cooled type. The case where PM adhesion suppression coating is not applied to the inner wall surface of the pipe 6 of the EGR cooler 3 is shown. Curve III shows the case where PM adhesion suppression coating is applied to the inner wall surface of the pipe 6 of the first water-cooled EGR cooler 4. .

曲線IIに示すように前段の第１の水冷式ＥＧＲクーラ３のパイプ６の内壁面にＰＭ付着抑制コーティングを施さない場合は、パイプ６の内壁面へのＰＭの付着に伴い第１の水冷式クーラ３のクーラ温度効率が低下し、これに伴い全体のクーラ温度効率も低下する。
また、曲線IIIに示すようにパイプ６の内壁面にＰＭ付着抑制コーティングを施した場合は、パイプ６の内壁面にＰＭが付着し難くクーラ温度効率の低下が抑制される。運転期間が長くなるに伴いＰＭが徐々にパイプ６の内壁面に付着してクーラ温度効率が低下する。パイプ６の内壁面に付着したＰＭは、エンジン停止後冷却水の温度が低下し、これに伴いパイプ６の温度が低下した際の収縮等により剥離される。この結果、段差部IIIａに示すようにクーラ温度効率が再び向上する。 As shown in curve II, when the PM adhesion suppression coating is not applied to the inner wall surface of the pipe 6 of the first water-cooled EGR cooler 3 in the previous stage, the first water-cooled type is accompanied with the adhesion of PM to the inner wall surface of the pipe 6. The cooler temperature efficiency of the cooler 3 is lowered, and accordingly, the overall cooler temperature efficiency is also lowered.
Further, when the PM adhesion suppression coating is applied to the inner wall surface of the pipe 6 as shown by the curve III, it is difficult for PM to adhere to the inner wall surface of the pipe 6 and the decrease in cooler temperature efficiency is suppressed. As the operation period becomes longer, PM gradually adheres to the inner wall surface of the pipe 6 and the cooler temperature efficiency decreases. The PM adhering to the inner wall surface of the pipe 6 is peeled off due to contraction or the like when the temperature of the cooling water decreases after the engine stops and the temperature of the pipe 6 decreases accordingly. As a result, as shown in the stepped portion IIIa, the cooler temperature efficiency is improved again.

このようにして段差部IIIａ、IIIｂに示すように付着したＰＭの剥離が促進されて長期に亘りＰＭ付着量を少なく抑えることが可能となり、前段の第１の冷却水ＥＧＲクーラ３の温度効率の低下が抑制される。このように、ＥＧＲガス通路２におけるＥＧＲガス冷却部１を水冷２段クーラ構造とすることで、クーラ温度効率の劣化抑制効果を得ることが可能となる。   In this way, the separation of the adhering PM is promoted as shown in the stepped portions IIIa and IIIb, and the amount of PM adhering can be reduced for a long period of time, and the temperature efficiency of the first cooling water EGR cooler 3 in the previous stage can be reduced. Reduction is suppressed. As described above, the EGR gas cooling section 1 in the EGR gas passage 2 has a water-cooled two-stage cooler structure, so that the effect of suppressing the deterioration of the cooler temperature efficiency can be obtained.

また、第１の水冷式ＥＧＲクーラ３、第２の水冷式ＥＧＲクーラ４の温度効率が安定して劣化によりサチュレートする温度効率（約７０〜６０％）と初期温度効率（約９０％）がかけ離れていないために、サチュレートした高効率を維持したい場合などに、初期効率が高すぎてＥＧＲ冷却水が沸騰する症状を緩和することができる。
尚、上記実施形態では、後段の第２の水冷式ＥＧＲクーラ４に多段積層型のプレートフィン式クーラを使用した場合について記述したが、これに限るものではなく、前段の第１の水冷式ＥＧＲクーラ３と同様に多管式クーラを使用してもよい。 In addition, the temperature efficiency (about 70 to 60%) in which the temperature efficiency of the first water-cooled EGR cooler 3 and the second water-cooled EGR cooler 4 is stabilized and saturates due to deterioration is far from the initial temperature efficiency (about 90%). Therefore, when it is desired to maintain the saturated high efficiency, it is possible to relieve the symptom that the initial efficiency is too high and the EGR cooling water boils.
In the above-described embodiment, the case where a multi-stage laminated plate fin type cooler is used for the second water-cooled EGR cooler 4 in the subsequent stage is described. However, the present invention is not limited to this, and the first water-cooled EGR in the previous stage is used. As with the cooler 3, a multi-tube cooler may be used.

更に、第２の水冷式ＥＧＲクーラ４のＥＧＲガス通路１４の内壁面及びフィン１６の表面にもＰＭ付着抑制コーティング処理を施してもよい。   Further, the PM adhesion suppression coating treatment may be applied to the inner wall surface of the EGR gas passage 14 and the surface of the fin 16 of the second water-cooled EGR cooler 4.

本発明に係るＥＧＲ装置のＥＧＲガス冷却部の断面図である。It is sectional drawing of the EGR gas cooling part of the EGR apparatus which concerns on this invention. 図１に示す第１の水冷式ＥＧＲクーラの断面図である。図である。It is sectional drawing of the 1st water cooling type EGR cooler shown in FIG. FIG. 図１に示す第２の水冷式ＥＧＲクーラの冷却水通路とＥＧＲガス通路とから成る一組の熱換器の説明図である。It is explanatory drawing of one set of heat exchangers which consist of the cooling water channel | path and EGR gas channel | path of the 2nd water cooling type EGR cooler shown in FIG. 図１に示すＥＧＲガス冷却部における水冷２段クーラの温度効率劣化抑制効果の一例を示すグラフである。It is a graph which shows an example of the temperature efficiency degradation inhibitory effect of the water-cooled two-stage cooler in the EGR gas cooling part shown in FIG.

符号の説明Explanation of symbols

１ ＥＧＲガス冷却部
２ ＥＧＲパイプ
３ 第１の水冷式ＥＧＲクーラ
４ 第２の水冷式ＥＧＲクーラ
５、１１ ケース
６ パイプ（ＥＧＲガス通路）
７ 隔壁
８ 冷却水通路
１２ 平板
１３ 冷却水通路
１４ ＥＧＲガス通路
１５ コア（熱交換器）
１６ フィン
１７、１８、１９ 冷却水パイプ DESCRIPTION OF SYMBOLS 1 EGR gas cooling part 2 EGR pipe 3 1st water cooling type EGR cooler 4 2nd water cooling type EGR cooler 5, 11 Case 6 Pipe (EGR gas passage)
7 Bulkhead 8 Cooling water passage 12 Flat plate 13 Cooling water passage 14 EGR gas passage 15 Core (heat exchanger)
16 Fin 17, 18, 19 Cooling water pipe

Claims (3)

エンジンの排気通路と吸気通路とを接続するＥＧＲ通路と、
前記ＥＧＲ通路の排気流れ上流側に介挿された第１の水冷式ＥＧＲクーラと、
前記第１の水冷式ＥＧＲクーラの下流のＥＧＲ通路に介装された第２の水冷式ＥＧＲクーラと
を備えたことを特徴とするＥＧＲ装置。 An EGR passage connecting the exhaust passage and the intake passage of the engine;
A first water-cooled EGR cooler inserted upstream of the exhaust flow in the EGR passage;
An EGR apparatus comprising: a second water-cooled EGR cooler interposed in an EGR passage downstream of the first water-cooled EGR cooler. 前記第１の水冷式ＥＧＲクーラが多管式クーラにより構成され、前記第２の水冷式ＥＧＲクーラが多段式積層型のフィン式クーラにより構成したことを特徴とする請求項１記載のＥＧＲ装置。   2. The EGR apparatus according to claim 1, wherein the first water-cooled EGR cooler is configured by a multi-tubular cooler, and the second water-cooled EGR cooler is configured by a multi-stage stacked fin-type cooler. 前記第１の水冷式ＥＧＲクーラの排気ガス通路壁に煤の付着を抑制する付着抑制剤がコーティングされていることを特徴とする請求項１又は２記載のＥＧＲ装置。   The EGR device according to claim 1 or 2, wherein an adhesion inhibitor that suppresses adhesion of soot is coated on an exhaust gas passage wall of the first water-cooled EGR cooler.
JP2004323967A 2004-11-08 2004-11-08 Egr device Pending JP2006132470A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2004323967A JP2006132470A (en) 2004-11-08 2004-11-08 Egr device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2004323967A JP2006132470A (en) 2004-11-08 2004-11-08 Egr device

Publications (1)

Publication Number Publication Date
JP2006132470A true JP2006132470A (en) 2006-05-25

Family

ID=36726238

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2004323967A Pending JP2006132470A (en) 2004-11-08 2004-11-08 Egr device

Country Status (1)

Country Link
JP (1) JP2006132470A (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010025033A (en) * 2008-07-22 2010-02-04 Hino Motors Ltd Egr device for internal combustion engine
US20110303200A1 (en) * 2011-03-03 2011-12-15 New Vision Fuel Technology, Inc. Passive re-induction apparatus, system, and method for recirculating exhaust gas in gasoline and diesel engines
JP2012207549A (en) * 2011-03-29 2012-10-25 Hino Motors Ltd Egr device
JP2013036338A (en) * 2011-08-03 2013-02-21 Toyota Motor Corp Egr system of internal combustion engine
US8490606B2 (en) 2011-03-03 2013-07-23 New Vision Fuel Technology, Inc. Passive re-induction apparatus, system, and method for recirculating exhaust gas in gasoline and diesel engines
JP2013224586A (en) * 2012-04-19 2013-10-31 Toyota Motor Corp Egr device for internal combustion engine
JP2015165554A (en) * 2014-02-05 2015-09-17 パナソニック株式会社 Thermoelectric generator unit and thermoelectric generation system
KR20160045341A (en) * 2014-10-17 2016-04-27 현대자동차주식회사 Egr cooler for vehicle
US20180051660A1 (en) * 2016-08-19 2018-02-22 General Electric Company Method and systems for an exhaust gas recirculation cooler including two sections
KR101887743B1 (en) 2016-04-22 2018-08-10 현대자동차주식회사 Exhaust system for vehicle and control method for the same
JP2020153591A (en) * 2019-03-20 2020-09-24 株式会社ティラド Header plate-less type heat exchanger

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010025033A (en) * 2008-07-22 2010-02-04 Hino Motors Ltd Egr device for internal combustion engine
US20110303200A1 (en) * 2011-03-03 2011-12-15 New Vision Fuel Technology, Inc. Passive re-induction apparatus, system, and method for recirculating exhaust gas in gasoline and diesel engines
US8276571B2 (en) * 2011-03-03 2012-10-02 New Vision Fuel Technology, Inc. Passive re-induction apparatus, system, and method for recirculating exhaust gas in gasoline and diesel engines
US8490606B2 (en) 2011-03-03 2013-07-23 New Vision Fuel Technology, Inc. Passive re-induction apparatus, system, and method for recirculating exhaust gas in gasoline and diesel engines
JP2012207549A (en) * 2011-03-29 2012-10-25 Hino Motors Ltd Egr device
JP2013036338A (en) * 2011-08-03 2013-02-21 Toyota Motor Corp Egr system of internal combustion engine
JP2013224586A (en) * 2012-04-19 2013-10-31 Toyota Motor Corp Egr device for internal combustion engine
JP2015165554A (en) * 2014-02-05 2015-09-17 パナソニック株式会社 Thermoelectric generator unit and thermoelectric generation system
KR20160045341A (en) * 2014-10-17 2016-04-27 현대자동차주식회사 Egr cooler for vehicle
KR102142662B1 (en) * 2014-10-17 2020-08-07 현대자동차주식회사 Egr cooler for vehicle
KR101887743B1 (en) 2016-04-22 2018-08-10 현대자동차주식회사 Exhaust system for vehicle and control method for the same
US20180051660A1 (en) * 2016-08-19 2018-02-22 General Electric Company Method and systems for an exhaust gas recirculation cooler including two sections
US10352278B2 (en) * 2016-08-19 2019-07-16 Ge Global Sourcing Llc Method and systems for an exhaust gas recirculation cooler including two sections
JP2020153591A (en) * 2019-03-20 2020-09-24 株式会社ティラド Header plate-less type heat exchanger
JP7286362B2 (en) 2019-03-20 2023-06-05 株式会社ティラド Header plateless heat exchanger

Similar Documents

Publication Publication Date Title
JP2006132470A (en) Egr device
US20050098307A1 (en) Gas cooling device
JP2015155692A (en) intercooler
JP5784267B2 (en) Flat heat transfer tube for EGR cooler and EGR cooler using this flat heat transfer tube
JP5145981B2 (en) Parts cooling structure
JP2008232142A (en) Cooled egr system and heat exchanger for system thereof
JP2002054511A (en) Egr cooler
JP2007315324A (en) Cooling structure of egr cooler
JP2006118436A (en) Bonnet for egr gas cooling device
JP2001027158A (en) Egr gas cooling system
JP2008069756A (en) Cooling system for vehicle
JP2007225137A (en) Multitubular heat exchanger and heat transfer tube for exhaust gas cooling device
JP2006200490A (en) Exhaust gas cooling device for exhaust gas recirculating system
JP2002180915A (en) Egr cooler
JP2011196620A (en) Ebullient cooling type heat exchanger
DE502004004210D1 (en) heat exchangers
JP2003161209A (en) Egr cooler
JP2010078233A (en) Shell-and-tube exchanger
JP2006138538A (en) Flat heat exchanger tube, and multitubular heat exchanger and multitubular heat exchange type egr gas cooling device comprised by incorporating the heat exchanger tube
JP2000265908A (en) Egr gas cooling device
JP2003214262A (en) Egr gas cooling device
JPH11118370A (en) Double tube type heat exchanger
JP2007255860A (en) Absorber for air-cooled absorption type refrigerating device
JP2004124808A (en) Exhaust gas recirculation cooler
JP2008128627A (en) Water-cooled condenser

Legal Events

Date Code Title Description
RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20060928

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20070419

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20090831

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20090902

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20100113