JPH11117751A - Egr device for supercharging engine - Google Patents
Egr device for supercharging engineInfo
- Publication number
- JPH11117751A JPH11117751A JP9278334A JP27833497A JPH11117751A JP H11117751 A JPH11117751 A JP H11117751A JP 9278334 A JP9278334 A JP 9278334A JP 27833497 A JP27833497 A JP 27833497A JP H11117751 A JPH11117751 A JP H11117751A
- Authority
- JP
- Japan
- Prior art keywords
- egr
- passage
- egr gas
- gas
- intake
- 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
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
- F02M26/07—Mixed pressure loops, i.e. wherein recirculated exhaust gas is either taken out upstream of the turbine and reintroduced upstream of the compressor, or is taken out downstream of the turbine and reintroduced downstream of the compressor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/08—EGR systems specially adapted for supercharged engines for engines having two or more intake charge compressors or exhaust gas turbines, e.g. a turbocharger combined with an additional compressor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
- F02B29/04—Cooling of air intake supply
- F02B29/0406—Layout of the intake air cooling or coolant circuit
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
- F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
- F02M26/23—Layout, e.g. schematics
- F02M26/28—Layout, e.g. schematics with liquid-cooled heat exchangers
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Supercharger (AREA)
- Exhaust-Gas Circulating Devices (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、過給機付きディー
ゼルエンジンなどにおいて、NOxの排出量を低減する
ために、排気ガスの一部を吸気側に還流する過給式エン
ジンのEGR装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EGR device for a supercharged engine in which a part of exhaust gas is recirculated to an intake side in order to reduce a NOx emission in a turbocharged diesel engine or the like. It is.
【0002】[0002]
【従来の技術】ディーゼルエンジン等の排気ガス対策に
おいて、排気ガス中のNOxの排出量を低減するため
に、不活性ガスである排気ガスの一部を吸気側に還流す
ることによって、燃焼温度を低く抑えて、NOxの生成
を抑制するEGR(排気再循環)が有効であることが知
られており、広く実用化されている。2. Description of the Related Art In exhaust gas countermeasures for diesel engines and the like, in order to reduce the amount of NOx emitted from exhaust gas, the combustion temperature is reduced by recirculating a part of the exhaust gas, which is an inert gas, to the intake side. It is known that EGR (exhaust gas recirculation), which suppresses NOx generation while keeping it low, is effective and widely used.
【0003】このEGR装置は過給式エンジンにも適用
され、図3に示すように排気マニホールド12aから排気
ガスG2を取り出し、EGRクーラー7を配設したEG
R通路9を経由して、吸気通路11の新気Aに混入して吸
気マニホールド11aへ還流させてEGRを行っている。
しかし、過給式エンジンにおいては、エンジン負荷の上
昇に伴い、吸気圧(ブート圧)が高くなり、排気圧より
高圧になってくるので、EGRガスG2を吸気通路11へ
還流させることができなくなる。[0003] This EGR device is also applied to a supercharged engine, and as shown in FIG. 3, an exhaust gas G2 is taken out from an exhaust manifold 12a and an EG provided with an EGR cooler 7 is provided.
The EGR is performed by mixing the fresh air A in the intake passage 11 through the R passage 9 and recirculating the mixture to the intake manifold 11a.
However, in the supercharged engine, as the engine load increases, the intake pressure (boot pressure) increases and becomes higher than the exhaust pressure, so that the EGR gas G2 cannot be recirculated to the intake passage 11. .
【0004】そのため、排気通路12に通じるウェイスト
ゲート12bを開いて排気ガスG3を流出させることによ
り排気圧力を下げ、それによってタービン2の回転数を
低下させることにより吸気圧力を低減して、EGRガス
G2を吸気通路11に還流させる方法がある。しかし、こ
の方法を取ると新気Aの量が減少し、スモークの増大を
引き起こすので、EGRできる領域は、図2(a)に示
すように、低負荷でかつ中回転以下のエンジンの運転領
域Eに限られてしまうという問題がある。Therefore, the exhaust pressure is reduced by opening the waste gate 12b communicating with the exhaust passage 12 and the exhaust gas G3 is caused to flow out, thereby reducing the rotational speed of the turbine 2 and thereby reducing the intake pressure, thereby reducing the EGR gas. There is a method of returning G2 to the intake passage 11. However, this method reduces the amount of fresh air A and causes an increase in smoke. Therefore, the region where EGR can be performed is, as shown in FIG. There is a problem that it is limited to E.
【0005】また、タービン2の入口の断面積を可変に
した可変容量型ターボチャージャ(VGターボ)では、
入口の断面積をコントロールすることでタービン回転数
を変化させて、排気圧と吸気圧を制御してEGR可能な
領域を拡大している。この場合においては、図2(b)
に示すような中負荷のEで示すエンジン運転領域までE
GR可能となるが、更にNOxを低減して排気ガスを浄
化するために、エンジンの高負荷運転領域でもEGR可
能にしたいという要求がある。In a variable capacity turbocharger (VG turbo) in which the cross-sectional area of the inlet of the turbine 2 is variable,
By controlling the cross-sectional area of the inlet and changing the turbine speed, the exhaust pressure and the intake pressure are controlled to expand the EGR-capable region. In this case, FIG.
Up to the engine operating range indicated by E with medium load as shown in
Although GR becomes possible, there is a demand for enabling EGR even in a high-load operation region of the engine in order to further reduce NOx and purify exhaust gas.
【0006】この要求に関して、特開平3−11766
5号、特開平5−180089号、特開平5−8985
9号等に、EGRガスをコンプレッサによって圧縮して
昇圧し、この昇圧したEGRガスを吸気通路側に還流す
るように構成することによって、EGR領域を拡大する
EGR装置が提案されている。[0006] Regarding this request, Japanese Patent Laid-Open Publication No.
5, JP-A-5-180089, JP-A-5-8985
No. 9 proposes an EGR device that expands the EGR region by compressing the EGR gas by a compressor to increase the pressure and recirculating the increased EGR gas to the intake passage side.
【0007】[0007]
【発明が解決しようとする課題】しかしながら、特開平
3−117665号の装置は、エンジンによって駆動さ
れるコンプレッサによりEGRガスを圧縮し、アキュム
レータタンク内に蓄圧してから供給しているために、エ
ンジンの駆動力がこのコンプレッサに使用されるのでそ
の分エンジン出力のロスが大きくなる。このロスは、エ
ンジンが高回転、高負荷になるほど大きくなるので、高
出力が必要な時程ロスが大きくなるという問題がある。
更に、高回転、高負荷領域においてEGRを行うため
に、容量の大きいコンプレッサ、アキュムレータが必要
になるという問題がある。However, in the device disclosed in Japanese Patent Application Laid-Open No. 3-117665, since the EGR gas is compressed by a compressor driven by the engine and stored in an accumulator tank, the EGR gas is supplied. Is used for this compressor, so that the loss of engine output increases accordingly. This loss increases as the engine speed increases and the load increases. Therefore, there is a problem that the loss increases when high output is required.
Further, there is a problem that a compressor and an accumulator having a large capacity are required to perform the EGR in a high rotation speed and a high load region.
【0008】また、特開平5−180089号の装置
は、排気ガスで駆動されるタービンを排気通路に設けて
このタービンに連結したEGRガスコンプレッサでEG
Rガスを加圧して、吸気通路に還流させている。しか
し、この装置においては排気通路に直列に排気ガスのパ
ワーを回収するパワータービンを含めて3つのタービン
を設けているため、EGR作動時に排気マニホールドの
排気圧が大幅に上昇するので、ポンピングロスが大きく
なって燃費が悪化するという問題と、高負荷運転におい
て新気の減少を招き黒煙が発生してEGRを行うことの
できる領域が限定されるという問題がある。In the apparatus disclosed in Japanese Patent Application Laid-Open No. H5-180089, a turbine driven by exhaust gas is provided in an exhaust passage, and an EGR gas compressor connected to the turbine is used for EG.
The R gas is pressurized and returned to the intake passage. However, in this device, since three turbines including a power turbine for recovering the power of the exhaust gas are provided in series in the exhaust passage, the exhaust pressure of the exhaust manifold rises significantly during the EGR operation, so that pumping loss is reduced. There is a problem that the fuel efficiency is deteriorated due to the increase in size, and there is a problem that a region where the EGR can be performed due to the generation of black smoke due to a decrease in fresh air during high load operation is limited.
【0009】そして、特開平5−89859号の装置
は、第1のターボチャージャで得られた圧縮空気を分岐
して第2のターボチャージャを駆動し、この第2のター
ボチャージャのコンプレッサでEGRガスを昇圧し、そ
れと共に、このコンプレッサから圧縮空気を逃がして吸
気圧を下げてEGRを行っている。しかし、この装置で
は、圧縮空気を分岐するため、シリンダへ供給される圧
縮吸気量が減少するので、EGRガス量に対する吸気量
が減少してスモークが発生するという問題がある。The apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 5-89859 divides the compressed air obtained by the first turbocharger to drive the second turbocharger, and the EGR gas is compressed by the compressor of the second turbocharger. , And at the same time, the compressed air is released from the compressor to lower the intake pressure to perform EGR. However, in this device, since the compressed air is branched, the amount of compressed intake air supplied to the cylinder is reduced, so that there is a problem that the amount of intake air with respect to the amount of EGR gas is reduced and smoke is generated.
【0010】本発明は、上述の問題を解決するためにな
されたものであり、その目的は、エンジンの高負荷運転
時でもEGRが可能で、しかも、シリンダへの吸気量を
十分に確保できてスモークの発生や燃料消費の悪化を防
止できると共に、更に、エンジンの運転状態に応じてE
GRガスを昇圧して、効率よくEGRを行うことができ
て、エンジンの全運転領域で排気ガス中のNOxの排出
量を低減できる過給式エンジンのEGR装置を提供する
ことにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to make it possible to perform EGR even during high-load operation of an engine and to secure a sufficient amount of intake air to a cylinder. The generation of smoke and the deterioration of fuel consumption can be prevented.
It is an object of the present invention to provide an EGR device for a supercharged engine capable of efficiently performing EGR by increasing the pressure of GR gas and reducing the emission amount of NOx in exhaust gas in the entire operation range of the engine.
【0011】[0011]
【課題を解決するための手段】以上のような目的を達成
するための過給式エンジンのEGR装置は、エンジンの
排気通路に設けたタービンによって、吸気通路に設けた
コンプレッサを駆動する過給式エンジンにおいて、前記
排気通路と前記吸気通路とを接続したEGR通路に、前
記タービンによって駆動され、かつ、EGRガスを昇圧
して前記吸気通路に還流するEGRガスコンプレッサを
設けると共に、該EGRガスコンプレッサの上流側の前
記EGR通路に新気を導入する第2吸気通路を設けて、
該第2吸気通路と前記EGR通路との連結部に制御弁を
配設し、該制御弁を制御することにより、EGRガス、
EGRガスと新気の混合ガス、新気を選択的に前記EG
Rガスコンプレッサに供給できるように構成したもので
ある。SUMMARY OF THE INVENTION In order to achieve the above object, a supercharged EGR system for a supercharged engine drives a compressor provided in an intake passage by a turbine provided in an exhaust passage of the engine. In the engine, an EGR gas compressor driven by the turbine and pressurizing EGR gas and returning to the intake passage is provided in an EGR passage connecting the exhaust passage and the intake passage. A second intake passage for introducing fresh air into the upstream EGR passage;
A control valve is provided at a connection portion between the second intake passage and the EGR passage, and the control valve is controlled so that EGR gas,
A mixed gas of EGR gas and fresh air,
It is configured so that it can be supplied to the R gas compressor.
【0012】そして、クラッチ機構を設けずに、常にE
GRガスコンプレッサを駆動すると共に、制御弁の制御
により、エンジンの運転状態に応じて、EGR通路に設
けた第2吸気通路から新気を供給して、EGRガスのみ
(第1吸気状態)、EGRガスと新気の両方(第2吸気
状態)、新気のみ(第3吸気状態)の吸気状態を選択し
てEGRクーラー側に送り込むことができる。Then, without providing a clutch mechanism, E
By driving the GR gas compressor and controlling the control valve, fresh air is supplied from the second intake passage provided in the EGR passage according to the operation state of the engine, and only the EGR gas (first intake state) is supplied. An intake state in which both gas and fresh air (second intake state) and only fresh air (third intake state) can be selected and sent to the EGR cooler side.
【0013】そのため、エンジンの低負荷・低回転領域
等では、EGRガスを一部または全部供給して、EGR
ガスの量を多くして、又はEGRガスのみを供給してE
GRを行うことができる。また、負荷の増大時には、E
GRガスと新気を必要なEGR率になるよう割合にして
供給できる。そして、高負荷運転領域においては、新気
の量を多くして、又は新気のみを供給することができ
る。更に、加速運転時には、新気のみを供給してスモー
クの発生を抑制できる。For this reason, in the low load / low rotation range of the engine or the like, the EGR gas is supplied partially or entirely to the EGR gas.
E by increasing the amount of gas or supplying only EGR gas
GR can be performed. When the load increases, E
The GR gas and fresh air can be supplied at a ratio so as to have a required EGR rate. Then, in the high load operation region, the amount of fresh air can be increased or only fresh air can be supplied. Furthermore, at the time of the acceleration operation, generation of smoke can be suppressed by supplying only fresh air.
【0014】また、EGRガスコンプレッサ用のタービ
ンを新たに設ける必要がなくなるので、排気圧の上昇を
防ぐことができ、燃料消費の悪化を防止できる。その
上、吸気の分岐及び逃がしによる吸気量の減少がないの
で、シリンダに供給される吸気量を十分に確保でき、ス
モークの発生を防止しながら、EGRを行うことができ
る。Further, since it is not necessary to newly provide a turbine for the EGR gas compressor, it is possible to prevent an increase in exhaust pressure and to prevent deterioration of fuel consumption. In addition, since there is no decrease in the intake air amount due to branching and release of the intake air, the intake air amount supplied to the cylinder can be sufficiently ensured, and EGR can be performed while preventing generation of smoke.
【0015】[0015]
【発明の実施の形態】以下、図面を用いて、本発明に係
る過給式エンジンのEGR装置の実施の形態を説明す
る。図1に示すように、この過給式エンジン1において
は、タービン2を排気通路12に設けて排気ガスG1+G
2によって回転駆動し、この回転を軸2aで伝達して吸
気通路11に設けたコンプレッサ3を駆動して、新気A1
を圧縮して、この新気A1をインタークーラ6を経由し
て、吸気マニホールド11aに供給している。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a supercharged engine EGR device according to the present invention will be described with reference to the drawings. As shown in FIG. 1, in this supercharged engine 1, a turbine 2 is provided in an exhaust passage 12 and an exhaust gas G1 + G
2, the rotation is transmitted by a shaft 2a, and the compressor 3 provided in the intake passage 11 is driven to generate fresh air A1.
The fresh air A1 is supplied to the intake manifold 11a via the intercooler 6.
【0016】この過給式エンジン1の排気通路12と吸気
通路11とを接続するEGR通路9を設けると共に、この
EGR通路9にタービン2によってクラッチ機構を介さ
ずに直接駆動されるEGRガスコンプレッサ5を設け
て、EGRガスG2を昇圧して吸気通路11に還流するよ
うに構成する。このEGRガスコンプレッサ5は空気専
用のコンプレッサ3より過給度を高して、確実に吸気通
路11側にEGRガス等G2,A2を供給できるようにす
ると共に、EGRの最大時に充分なEGRガスG2を供
給できる能力を持たせて構成する。An EGR passage 9 for connecting the exhaust passage 12 and the intake passage 11 of the supercharged engine 1 is provided, and an EGR gas compressor 5 directly driven by the turbine 2 without a clutch mechanism in the EGR passage 9. Is provided so that the EGR gas G2 is pressurized and recirculated to the intake passage 11. The EGR gas compressor 5 has a higher supercharging degree than the air-only compressor 3 so that the EGR gas G2 and A2 can be reliably supplied to the intake passage 11 side, and a sufficient EGR gas G2 at the maximum EGR. With the ability to supply
【0017】更に、このEGRガスコンプレッサ5の上
流側のEGR通路9に新気A2を導入する第2吸気通路
13を設け、このEGR通路9と第2吸気通路13との連結
部に制御弁8を設けて、この制御弁8により、EGRガ
スコンプレッサ5側に流入するEGRガスG2の量と新
気A2の量を調整制御できるように構成する。また、エ
ンジン1の回転数を検出する回転数センサー14とエンジ
ンの負荷を検出する負荷センサー15とコントローラ(E
CU)20を設ける。そして、このコントローラ20が回転
数センサー14の出力と負荷センサー15の出力とを入力し
て、予め入力したEGRマップ30のデータに従って、エ
ンジンの負荷、速度に応じた制御弁8の弁開度のコント
ロールを行い、予め設定されたEGR率でEGRできる
ように構成する。Further, a second intake passage for introducing fresh air A2 into the EGR passage 9 upstream of the EGR gas compressor 5.
A control valve 8 is provided at a connection between the EGR passage 9 and the second intake passage 13, and the control valve 8 controls the amount of the EGR gas G2 flowing into the EGR gas compressor 5 and the fresh air A2. It is configured so that the amount can be adjusted and controlled. Further, a rotation speed sensor 14 for detecting the rotation speed of the engine 1, a load sensor 15 for detecting the load of the engine 1, and a controller (E
CU) 20. The controller 20 receives the output of the rotation speed sensor 14 and the output of the load sensor 15 and determines the valve opening of the control valve 8 according to the load and speed of the engine in accordance with the data of the EGR map 30 previously input. Control is performed so that EGR can be performed at a preset EGR rate.
【0018】このEGRマップ30は、エンジン1の大き
さ、使用状態などによって異なり、また、使用する国の
排気ガス制限値によっても詳細な部分は異なってくる。
この構成を簡単化して述べると、排気通路12のタービン
2によって同回転で駆動される2つのコンプレッサ3,
5を設けて、一つのコンプレッサ3は空気専用に、もう
一つのEGRガスコンプレッサ5は制御弁8によってE
GRガスG2のみ、新気A2とEGRガスG2、又は新
気A2のみを選択的に吸入するように構成したEGR装
置である。The details of the EGR map 30 differ depending on the size of the engine 1, the operating conditions, and the like, and the details also differ depending on the exhaust gas limit value of the country of use.
To briefly describe this configuration, two compressors 3 driven by the turbine 2 in the exhaust passage 12 at the same rotation,
5, one compressor 3 is dedicated to air, and the other EGR gas compressor 5 is
The EGR device is configured to selectively suck only the GR gas G2, the fresh air A2 and the EGR gas G2, or only the fresh air A2.
【0019】以上の構成のEGR装置においては、制御
弁8をコントロールすることにより、エンジンの運転状
態を回転数や負荷等で検出して、この運転状態に対する
最適のEGR率でEGRを行うことができる。つまり、
制御弁8を調整してEGRガスG2のみをEGRガスコ
ンプレッサ5側に供給する第1吸気状態により、低負荷
・低回転運転領域におけるEGRを行うことができる。
低負荷・低回転運転領域では、大量のEGRガスを要す
るので、制御弁8はEGRガスG2のみをEGRガスコ
ンプレッサ5に供給するよう調整を行う。In the EGR device having the above-described configuration, by controlling the control valve 8, the operating state of the engine is detected based on the number of revolutions, load, and the like, and the EGR is performed at the optimum EGR rate for the operating state. it can. That is,
By performing the first intake state in which the control valve 8 is adjusted to supply only the EGR gas G2 to the EGR gas compressor 5, the EGR can be performed in the low-load / low-speed operation region.
Since a large amount of EGR gas is required in the low-load / low-speed operation region, the control valve 8 performs adjustment so that only the EGR gas G2 is supplied to the EGR gas compressor 5.
【0020】そして、制御弁8の開度を調整して、新気
を導入することにより、EGRガスG2と新気A2の混
合ガスを供給する第2吸気状態により、低負荷・低回転
領域において、EGRガスが過剰になって吸気不足にな
っても対応できる。また、この第2吸気状態で、制御弁
8の開度を調整してEGRガスG2と新気A2を必要な
EGR率になるような割合にして、EGRガスコンプレ
ッサ5側に供給することにより、負荷が増大してEGR
率を減らす必要が生じる中・高負荷の運転領域に対応し
たEGRを行うことができる。Then, by adjusting the opening of the control valve 8 and introducing fresh air, the second intake state in which a mixed gas of the EGR gas G2 and the fresh air A2 is supplied, the low-load / low-rotation range is achieved. It is possible to cope with a shortage of intake air due to excessive EGR gas. In the second intake state, the opening degree of the control valve 8 is adjusted to supply the EGR gas G2 and the fresh air A2 to the EGR gas compressor 5 at a ratio such that the required EGR rate is obtained. Load increases and EGR
It is possible to perform EGR corresponding to a medium / high load operation region in which it is necessary to reduce the rate.
【0021】負荷の増加に伴い、吸気圧は過給機のコン
プレッサ3によって圧縮されているので、排気ガス圧<
吸気圧(ブースト圧)の状態となるが、EGR通路9に
設けたEGRガスコンプレッサ5により、EGRガスG
2と新気A2の圧縮及び昇圧を行っているので、EGR
ガスG2と新気A2の圧力を新気A1の吸気圧よりも高
圧にすることができ、EGRを円滑に行うことができ
る。As the load increases, the intake pressure is compressed by the compressor 3 of the supercharger.
Although the state becomes the intake pressure (boost pressure), the EGR gas G is compressed by the EGR gas compressor 5 provided in the EGR passage 9.
2 and the fresh air A2 are compressed and pressurized.
The pressure of the gas G2 and the fresh air A2 can be made higher than the intake pressure of the fresh air A1, and EGR can be performed smoothly.
【0022】更に、新気のみを供給する第3吸気状態に
より、全くEGRを必要とせず、新気量が不足しがちな
加速運転時に充分な新気を供給できるので、スモークの
発生を抑制することができる。従って、エンジンの運転
状態に応じて、制御弁8を調整制御することにより、新
気A2のみ、新気A2とEGRガスG2との混合ガス、
EGRガスG2のみに、選択して、しかも混合ガスの混
合率をも変化させて、EGRガスコンプレッサ5側に供
給できるので、最適のEGR率で効率よくEGRを行う
ことができる。そのため、過給式エンジンの全運転領域
で排気ガス中のNOxの排出量を低減できる。Further, in the third intake state in which only fresh air is supplied, it is possible to supply sufficient fresh air at the time of acceleration operation in which the amount of fresh air tends to be insufficient without requiring any EGR, thereby suppressing generation of smoke. be able to. Therefore, by adjusting and controlling the control valve 8 in accordance with the operating state of the engine, only the fresh air A2, a mixed gas of the fresh air A2 and the EGR gas G2,
The EGR gas can be supplied to the EGR gas compressor 5 side by selecting only the EGR gas G2 and changing the mixing ratio of the mixed gas, so that the EGR can be efficiently performed at the optimum EGR rate. Therefore, the emission amount of NOx in the exhaust gas can be reduced in the entire operating region of the supercharged engine.
【0023】更に、EGRガスG2をEGRガスコンプ
レッサ5で圧縮及び昇圧しているので、吸気圧力の高い
過給式エンジンの高負荷運転時でもEGRを円滑に行う
ことが可能となり、NOxの低減を図ることができる。
また、必要に応じて新気A2もEGRガスコンプレッサ
5で圧縮及び昇圧して供給できるので、シリンダへの吸
気量を十分に確保できてスモークの発生や燃料消費の悪
化を防止できる。Further, since the EGR gas G2 is compressed and pressurized by the EGR gas compressor 5, it is possible to smoothly perform the EGR even during the high load operation of the supercharged engine having a high intake pressure, thereby reducing NOx. Can be planned.
Further, if necessary, the fresh air A2 can also be compressed and pressurized by the EGR gas compressor 5 and supplied, so that a sufficient amount of intake air to the cylinder can be secured, and generation of smoke and deterioration of fuel consumption can be prevented.
【0024】その上、この制御弁8を制御して、EGR
ガス等G2,A2の流量を変化させることにより、ター
ボ2への負荷を変えることができ、ターボ2の回転数に
対してコンプレッサ3,5の効率がよい作動点で運転で
きるので、燃費も向上させることができる。そして、こ
の構成のEGR装置によれば、クラッチ制御のEGRガ
スコンプレッサを設けてEGRガスの昇圧が必要な時の
みにEGRガスコンプレッサを駆動する装置に対して、
クラッチ機構が不要になるので、よりコンパクトになっ
て、コストや信頼性も向上する。また、新気A2をEG
Rガスコンプレッサ5からも供給できるので、新気が不
足し易い加速時等に充分な新気A1+A2を供給でき
る。また、排ガスのエネルギー以外にコンプレッサを駆
動する動力を必要とせず、制御の対象も制御弁となるの
で制御機構が容易となる。In addition, the control valve 8 is controlled to
By changing the flow rates of the gas G2 and A2, the load on the turbo 2 can be changed, and the compressors 3 and 5 can be operated at an efficient operating point with respect to the rotation speed of the turbo 2, thereby improving fuel efficiency. Can be done. According to the EGR device having this configuration, an EGR gas compressor for clutch control is provided to drive the EGR gas compressor only when the pressure of the EGR gas needs to be increased.
Since a clutch mechanism is not required, the size is reduced, and the cost and reliability are improved. In addition, fresh air A2 is EG
Since it can also be supplied from the R gas compressor 5, a sufficient amount of fresh air A1 + A2 can be supplied at the time of acceleration or the like where fresh air tends to be insufficient. Further, power for driving the compressor other than the energy of the exhaust gas is not required, and the control target is also a control valve, so that the control mechanism is simplified.
【0025】[0025]
【発明の効果】以上に説明したように、本発明の過給式
エンジンのEGR装置によれば、EGR通路に吸気コン
プレッサと同軸にしたEGRガスコンプレッサを設ける
と共に、EGRガスコンプレッサの上流側の前記EGR
通路に新気を導入する第2吸気通路を設けて、この第2
吸気通路とEGR通路との連結部に制御弁を配設して、
この制御弁を制御して、EGRガスのみ、EGRガスと
新気、新気のみを選択的に吸気通路側に昇圧して供給す
るように構成したので、エンジンの運転状態に応じたE
GRガスおよび新気の供給を行うことができ、EGR時
には最適なEGR率でEGRを効率よく行うことができ
ると共に、新気の増加が必要な時には充分な新気を供給
できる。As described above, according to the EGR device for a supercharged engine of the present invention, an EGR gas compressor coaxial with an intake compressor is provided in an EGR passage, and the EGR gas compressor upstream of the EGR gas compressor is provided. EGR
A second intake passage for introducing fresh air into the passage is provided.
A control valve is provided at a connection between the intake passage and the EGR passage,
This control valve is controlled so that only EGR gas, EGR gas, fresh air, and fresh air alone are selectively boosted and supplied to the intake passage side.
GR gas and fresh air can be supplied, and at the time of EGR, EGR can be efficiently performed at an optimum EGR rate, and when fresh air needs to be increased, sufficient fresh air can be supplied.
【0026】そして、EGRガスをEGRガスコンプレ
ッサで昇圧して吸気通路に供給するので、高負荷運転領
域における吸気圧の高い状態でも円滑にEGRを行うこ
とができるので、EGR可能な範囲をエンジンの運転領
域全体に拡大することができる。従って、過給式エンジ
ンの全運転領域において排気ガス中のNOxの排出量を
低減でき、また、スモークの発生量も低減できる。Since the EGR gas is pressurized by the EGR gas compressor and supplied to the intake passage, the EGR can be performed smoothly even in the high intake pressure state in the high load operation range. It can be extended over the entire operating area. Therefore, it is possible to reduce the emission amount of NOx in the exhaust gas in the entire operation range of the supercharged engine, and also reduce the amount of smoke generated.
【図1】本発明に係る過給式エンジンのEGR装置の構
成図である。FIG. 1 is a configuration diagram of an EGR device for a supercharged engine according to the present invention.
【図2】従来技術のEGR領域を示す模式図で、(a)
は、過給式エンジンのEGR装置のEGR領域を、
(b)はVGターボエンジンにおけるEGR装置のEG
R領域を示す。FIG. 2 is a schematic view showing an EGR region according to the related art, and FIG.
Is the EGR range of the EGR device of the supercharged engine,
(B) EG of the EGR device in the VG turbo engine
The R region is shown.
【図3】従来技術の過給式エンジンのEGR装置の構成
図である。FIG. 3 is a configuration diagram of a conventional EGR device for a supercharged engine.
1 エンジン 2 過給機のター
ビン 3 過給機のコンプレッサ 5 EGRガスコ
ンプレッサ 6 インタークーラ 7 EGRクーラ 9 EGR通路 11 吸気通路 11a 吸気マニホールド 12 排気通路 12a 排気マニホールド 13 第2吸気通路 14 回転数センサー 15 負荷センサー 20 コントローラ(ECU) 30 EGRマップDESCRIPTION OF SYMBOLS 1 Engine 2 Turbocharger turbine 3 Supercharger compressor 5 EGR gas compressor 6 Intercooler 7 EGR cooler 9 EGR passage 11 Intake passage 11a Intake manifold 12 Exhaust passage 12a Exhaust manifold 13 Second intake passage 14 Speed sensor 15 Load Sensor 20 Controller (ECU) 30 EGR map
Claims (1)
たタービン(2)によって、吸気通路(11)に設けたコ
ンプレッサ(3)を駆動する過給式エンジンにおいて、
前記排気通路(12)と前記吸気通路(11)とを接続した
EGR通路(9)に、前記タービン(2)によって駆動
され、かつ、EGRガス(G2)を昇圧して前記吸気通
路(11)に供給するEGRガスコンプレッサ(5)を設
けると共に、該EGRガスコンプレッサ(5)の上流側
の前記EGR通路(9)に新気(A2)を導入する第2
吸気通路(13)を設けて、該第2吸気通路(13)と前記
EGR通路(9)との連結部に制御弁(8)を配設し、
該制御弁(8)を制御することにより、EGRガス(G
2)、EGRガス(G2)と新気(A2)の混合ガス、
新気(A2)を選択的に前記EGRガスコンプレッサ
(5)に供給できるように構成した過給式エンジンのE
GR装置。1. A supercharged engine in which a compressor (3) provided in an intake passage (11) is driven by a turbine (2) provided in an exhaust passage (12) of the engine (1).
An EGR passage (9) connected to the exhaust passage (12) and the intake passage (11) is driven by the turbine (2) and pressurizes EGR gas (G2) to increase the pressure of the intake passage (11). And a second air inlet (A2) for introducing fresh air (A2) into the EGR passage (9) upstream of the EGR gas compressor (5).
An intake passage (13) is provided, and a control valve (8) is disposed at a connection between the second intake passage (13) and the EGR passage (9).
By controlling the control valve (8), the EGR gas (G
2) a mixed gas of EGR gas (G2) and fresh air (A2),
E of a supercharged engine configured to selectively supply fresh air (A2) to the EGR gas compressor (5).
GR device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP27833497A JP3627470B2 (en) | 1997-10-13 | 1997-10-13 | EGR device for supercharged engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP27833497A JP3627470B2 (en) | 1997-10-13 | 1997-10-13 | EGR device for supercharged engine |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH11117751A true JPH11117751A (en) | 1999-04-27 |
JP3627470B2 JP3627470B2 (en) | 2005-03-09 |
Family
ID=17595891
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JP27833497A Expired - Fee Related JP3627470B2 (en) | 1997-10-13 | 1997-10-13 | EGR device for supercharged engine |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003519309A (en) * | 1999-06-18 | 2003-06-17 | アライドシグナル インコーポレイテッド | Turbocharger with integrated exhaust gas recirculation pump |
-
1997
- 1997-10-13 JP JP27833497A patent/JP3627470B2/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003519309A (en) * | 1999-06-18 | 2003-06-17 | アライドシグナル インコーポレイテッド | Turbocharger with integrated exhaust gas recirculation pump |
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