JP2001003814A - Air-fuel ratio controller for mixer - Google Patents

Air-fuel ratio controller for mixer

Info

Publication number
JP2001003814A
JP2001003814A JP11170705A JP17070599A JP2001003814A JP 2001003814 A JP2001003814 A JP 2001003814A JP 11170705 A JP11170705 A JP 11170705A JP 17070599 A JP17070599 A JP 17070599A JP 2001003814 A JP2001003814 A JP 2001003814A
Authority
JP
Japan
Prior art keywords
gas
fuel
air
fuel ratio
engine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP11170705A
Other languages
Japanese (ja)
Other versions
JP3919974B2 (en
Inventor
Shinichiro Uematsu
真一郎 植松
Seiji Hikino
清治 引野
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.)
Hino Motors Ltd
Original Assignee
Hino Motors Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hino Motors Ltd filed Critical Hino Motors Ltd
Priority to JP17070599A priority Critical patent/JP3919974B2/en
Publication of JP2001003814A publication Critical patent/JP2001003814A/en
Application granted granted Critical
Publication of JP3919974B2 publication Critical patent/JP3919974B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/30Use of alternative fuels, e.g. biofuels

Landscapes

  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

PROBLEM TO BE SOLVED: To improve the fuel consumption and the exhaust gas characteristic without impairing the output performance and the combustion stability of a lean burn-type gas engine. SOLUTION: In the mixer 4 of a gas engine where the fuel gas is fed to a venturi part 6 mounted on an intake path 5 to obtain a lean mixture, an auxiliary supply means 8 is mounted in a low load zone of the engine for supplying the fuel gas to the intake path 5 at the downstream with respect to the venturi part 6, so that an air-fuel ratio of the lean mixture supplied in the low load zone is concentrated and corrected to a theoretical air-fuel ratio side to improve the combustion stability.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明はCNGを燃料とする
ガスエンジンに用いられるミキサの空燃比の制御装置に
係り、特に、リーンバーン方式のガスエンジンにおける
空燃比の制御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 air-fuel ratio control device for a mixer used in a gas engine using CNG as a fuel, and more particularly to an air-fuel ratio control device for a lean burn type gas engine.

【0002】[0002]

【従来の技術】ガスエンジンに用いられるベンチュリ方
式のミキサは、ベンチュリ部を通過する空気量に比例し
てガスの吸い出し流量が決定されるために、空燃比の制
御幅が狭い。また、理論空燃比より燃料の割合が少ない
希薄混合気を生成して燃焼室に供給するようにしたリー
ンバーン方式のガスエンジンにおいては、充分な空気量
を有するために燃料ガスの全量が燃焼に供されて燃費が
改善されるとともに、燃焼温度が低いためにNOxの生
成が抑制されて排気がクリーンであるという利点を有し
ている。
2. Description of the Related Art In a Venturi type mixer used in a gas engine, a control flow of an air-fuel ratio is narrow because a gas suction flow rate is determined in proportion to an amount of air passing through a Venturi section. Further, in a lean burn gas engine in which a lean mixture in which the proportion of fuel is smaller than the stoichiometric air-fuel ratio is generated and supplied to the combustion chamber, the entire amount of fuel gas is consumed for combustion because of a sufficient amount of air. This has the advantage of improving fuel economy and providing low exhaust gas temperature due to low combustion temperature, resulting in clean exhaust gas.

【0003】ところで、このようなリーンバーン方式の
ガスエンジンの場合においても、通常はベンチュリ部の
絞りを大きくすることにより、使用頻度が高い中負荷域
の空燃比制御に重点をおいていた。しかしながら、この
ようなリーンバーン方式のガスエンジンにおいては、高
負荷域においては燃料の割合をより少なくしても安定燃
焼が行われるにも拘らず、この希薄混合気をそのまま低
負荷域で供給すると燃焼が不安定になるために、エンジ
ン回転数が安定せず、あるいは、失火を起して排気特性
が悪化するという不具合が懸念される。
By the way, even in the case of such a lean burn type gas engine, usually, the throttle of the venturi portion is enlarged, so that the emphasis is placed on the air-fuel ratio control in a medium load region which is frequently used. However, in such a lean burn type gas engine, in the high load region, despite the fact that stable combustion is performed even if the proportion of fuel is reduced, this lean mixture is supplied as it is in the low load region. Since combustion becomes unstable, there is a concern that the engine speed will not be stable, or misfiring will occur and exhaust characteristics will deteriorate.

【0004】なお、このような不具合を解消すべく低負
荷域での燃焼安定性を重視して濃いめの希薄混合気を供
給するように設定した場合は、例えば商用車のように中
・高負荷域での運転頻度が高いエンジンの場合は、リー
ンバーン方式による燃費の改善効果が悪化するととも
に、燃焼温度が高くなってNOxの改善効果が低下する
という不具合があった。
[0004] In order to solve such a problem, if a setting is made to supply a rich lean mixture with an emphasis on combustion stability in a low load range, for example, a medium-to-high load like a commercial vehicle is used. In the case of an engine that is frequently operated in the region, the effect of improving the fuel economy by the lean burn method is deteriorated, and the combustion temperature is increased, so that the effect of improving NOx is deteriorated.

【0005】従って、リーンバーン方式のガスエンジン
においては、低負荷域での燃焼安定性および排気中に含
まれる未燃成分の量を減少しつつ、中・高負荷域での燃
費および排出ガス特性などを改善することは困難である
とされていた。
Accordingly, in a lean burn type gas engine, fuel consumption and exhaust gas characteristics in a medium / high load region are reduced while reducing the combustion stability in a low load region and the amount of unburned components contained in exhaust gas. It was said that it was difficult to improve such things.

【0006】[0006]

【発明が解決しようとする課題】本発明は上記実情に鑑
みてなされたものであって、ガスエンジンにリーンバー
ン方式を適用した場合においても低負荷域での燃焼安定
性はもとより、中・高負荷域での出力性能を犠牲にする
ことなく燃費および排ガス特性などを改善することを課
題としている。
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and even when a lean burn system is applied to a gas engine, not only combustion stability in a low load region but also medium / high combustion stability can be achieved. It is an object of the present invention to improve fuel efficiency and exhaust gas characteristics without sacrificing output performance in a load region.

【0007】[0007]

【課題を解決するための手段】上記課題を解決するため
に本発明は、吸気通路に設けたベンチュリ部に燃料ガス
を流出させることにより、理論空燃比より燃料の割合が
少ない希薄混合気を生成して燃焼室に供給するようにし
たリーンバーン方式のガスエンジン用ミキサにおいて、
ガスエンジンの低負荷域において前記ベンチュリ部より
下流の吸気通路に燃料ガスを供給する補助供給手段を設
けたことを特徴としている。なお、前記補助供給手段を
介して供給される燃料ガスの流量は、ガスエンジンの運
転状態もしくは吸気絞り弁の上下流間の差圧に基づいて
可変制御されるものであることが望ましい。
SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to produce a lean air-fuel mixture having a smaller fuel ratio than a stoichiometric air-fuel ratio by discharging fuel gas to a venturi section provided in an intake passage. In a lean burn type gas engine mixer that is supplied to the combustion chamber by
An auxiliary supply means for supplying fuel gas to an intake passage downstream of the venturi section in a low load region of the gas engine is provided. Preferably, the flow rate of the fuel gas supplied via the auxiliary supply means is variably controlled based on the operating state of the gas engine or the differential pressure between the upstream and downstream of the intake throttle valve.

【0008】[0008]

【発明の実施の形態】以下に本発明の実施形態を図に基
づいて詳細に説明する。図1は本発明に係るミキサの空
燃比制御装置の一実施形態を示す概略構成図であり、図
示しない燃料タンクから送出された燃料ガスは、ガスレ
ギュレータ2および調量弁3を介してミキサ4に供給さ
れる。なお、ミキサ4は従来同様にガスエンジン本体1
の吸気通路5に設けられ、そのベンチュリ部6を通流す
る空気による吸込作用で空気中に吸い出し供給される。
7は吸気絞り弁である。
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of an air-fuel ratio control device for a mixer according to the present invention. A fuel gas delivered from a fuel tank (not shown) is supplied to a mixer 4 via a gas regulator 2 and a metering valve 3. Supplied to It should be noted that the mixer 4 is a gas engine body 1 as in the prior art.
And is supplied to the air by the suction action of the air flowing through the venturi section 6.
7 is an intake throttle valve.

【0009】また、ミキサ4のベンチュリ部6より下流
で吸気絞り弁7より上流の吸気通路に設けたガスインジ
ェクタ8とガスレギュレータ2の中圧ガス出口をガスパ
イプ9を介して接続している。そして、ガスエンジン本
体1のエキゾーストマニホールド10に設けた酸素セン
サ11、インテークマニホールド12に設けた吸気圧セ
ンサ13および回転センサ14並びに絞り弁開度センサ
15の各出力が供給されるコントロールユニット16の
出力が制御信号として供給されるコントロールユニット
16を設けることにより、エンジンが低負荷域で運転さ
れていることを検出した場合にガスインジェクタ8から
吸気中に燃料ガスを補充供給して希薄混合気を理論空燃
比側に濃化補正するようにしている。
A gas injector 8 provided in an intake passage downstream of the venturi section 6 of the mixer 4 and upstream of the intake throttle valve 7 is connected to a medium-pressure gas outlet of the gas regulator 2 via a gas pipe 9. The output of the control unit 16 to which the respective outputs of the oxygen sensor 11 provided on the exhaust manifold 10 of the gas engine body 1, the intake pressure sensor 13 and the rotation sensor 14 provided on the intake manifold 12, and the throttle valve opening sensor 15 are supplied. Is provided as a control signal, and when it is detected that the engine is operating in a low load range, fuel gas is replenished and supplied from the gas injector 8 into the intake air to theoretically calculate a lean mixture. The enrichment correction is performed on the air-fuel ratio side.

【0010】すなわち、ミキサ6により生成される混合
気は、理論空燃比より燃料の割合が少ない希薄混合気で
あり、このような希薄混合気をエンジンの中・高負荷域
で供給することにより、燃焼効率を高くして燃費を改善
しつつ燃焼温度を低くしてNOxの生成を予防して排気
をクリーンなものとしている。
That is, the air-fuel mixture generated by the mixer 6 is a lean air-fuel mixture in which the proportion of fuel is smaller than the stoichiometric air-fuel ratio. By supplying such a lean air-fuel mixture in the middle and high load regions of the engine, The combustion efficiency is improved to improve the fuel efficiency, and the combustion temperature is lowered to prevent the generation of NOx, thereby making the exhaust gas cleaner.

【0011】ところで、高負荷での運転に適した空燃比
の混合気を生成するようにしたミキサ4を用いた場合
は、図2に実線で示した要求ガス流量に対して同図に二
点鎖線で示したように低負荷域でのガス流量が不足して
空燃比が薄くなり過ぎて燃焼が不安定になる。また、逆
に低負荷域で安定燃焼する程度の空燃比の希薄混合気を
清々するようにミキサ4をマッチングさせた場合は、同
図に破線で示したように高負荷域での流量が過剰になっ
て空燃比が濃くなって燃焼温度が上昇するためにNOx
排出量が増加するとともに燃費が悪化することはよく知
られている。
By the way, when the mixer 4 which generates an air-fuel mixture having an air-fuel ratio suitable for operation under a high load is used, the required gas flow rate shown by a solid line in FIG. As indicated by the dashed line, the gas flow rate in the low load region is insufficient, the air-fuel ratio becomes too thin, and the combustion becomes unstable. Conversely, when the mixers 4 are matched so that a lean mixture having an air-fuel ratio sufficient for stable combustion in a low-load region is obtained, the flow rate in a high-load region becomes excessive as shown by a broken line in FIG. NOx because the air-fuel ratio becomes rich and the combustion temperature rises
It is well known that fuel consumption worsens as emissions increase.

【0012】しかしながら、本実施形態のようにエンジ
ン1が低負荷域で運転されたときにガスインジェクタ8
から燃料ガスを補充供給して希薄混合気の空燃比を理論
空燃比側に濃化補正するようにした場合は、エンジンの
出力および排気特性を重視してミキサ4を中・高負荷に
マッチングさせた場合においても、低負荷域でガスイン
ジェクタ8から補充供給される燃料ガスで空燃比が濃化
補正されるために、燃焼が不安定になることはない。
However, when the engine 1 is operated in a low load range as in the present embodiment, the gas injector 8
If the air-fuel ratio of the lean mixture is corrected to the stoichiometric air-fuel ratio by replenishing and supplying the fuel gas from the engine, the mixer 4 is matched to medium / high load with emphasis on the engine output and exhaust characteristics. Even in such a case, the combustion is not unstable because the air-fuel ratio is corrected to be enriched by the fuel gas replenished and supplied from the gas injector 8 in the low load region.

【0013】ところで、硫黄あるいはリンなどが含まれ
ないCNGを燃料とするガスエンジンの場合において
も、オイルに添加剤として混入させた硫黄あるいはリン
などが燃焼して排気とともに排出される。従って、排気
中に含まれるHCなどの浄化手段として触媒コンバータ
を設けた場合は、該コンバータに充填した酸化触媒の表
面が硫黄あるいはリンなどの酸化物の被膜で次第に覆わ
れて該触媒の活性を損なうことがある。
By the way, even in the case of a gas engine using CNG containing no sulfur or phosphorus as fuel, sulfur or phosphorus mixed as an additive into oil is burned and discharged together with exhaust gas. Therefore, when a catalytic converter is provided as a means for purifying HC and the like contained in exhaust gas, the surface of the oxidation catalyst filled in the converter is gradually covered with a film of an oxide such as sulfur or phosphorus to reduce the activity of the catalyst. May be impaired.

【0014】しかしながら、上記のように低負荷域で混
合気を理論空燃比側に濃化補正すると、低負荷域で排出
される排気中に含まれるHCの濃度が増加する。する
と、増加したHCの酸化作用で図示しない触媒の温度が
上昇するために、硫黄あるいはリンなどの酸化被膜が還
元処理されて触媒の表面から脱落するために、低負荷域
で運転するたびに酸化触媒が賦活されるという副次的効
果を得ることもできる。
However, when the air-fuel mixture is corrected to the stoichiometric air-fuel ratio in the low load region as described above, the concentration of HC contained in the exhaust gas discharged in the low load region increases. Then, the temperature of the catalyst (not shown) increases due to the increased oxidizing action of HC, and the oxide film such as sulfur or phosphorus is reduced and falls off the surface of the catalyst. A secondary effect that the catalyst is activated can also be obtained.

【0015】なお、ミキサ6は上記実施形態のものに限
定されるものではなく、例えば図3に示したように調量
弁3で流量調整された燃料ガスをベンチュリ部6に設け
たメインポート6aおよびベンチュリ部6の直下流部に
設けたアイドルポート6bに分離させて供給するように
したものにも本発明を適用することができる。
The mixer 6 is not limited to the above embodiment. For example, as shown in FIG. 3, a main port 6a in which the fuel gas whose flow rate is adjusted by the metering valve 3 is provided in the venturi section 6 The present invention can also be applied to a configuration in which the air is supplied separately to an idle port 6b provided immediately downstream of the venturi section 6.

【0016】また、補充供給される燃料ガスの調量手段
は上記実施形態のようなガスインジェクタ8およびコン
トロールユニット16に限定されるものではない。すな
わち、例えば図3に示したようにベンチュリ部6の下流
に開口する補助ポート8aを設ける。そして、吸気絞り
弁7の上下流間の差圧に基づいて開度制御されるダイヤ
フラムバルブ8bを介装した補助通路8cを介して補助
ポート8aに燃料ガスを供給するようにした場合は、エ
ンジンの負荷の指標の一つである吸気絞り弁7の上下流
間の差圧に基づいて燃料の補充流量を一義的に決定する
ことができるために、制御装置を簡略化することができ
る利点がある。
Further, the metering means of the fuel gas supplied and supplied is not limited to the gas injector 8 and the control unit 16 as in the above embodiment. That is, for example, as shown in FIG. 3, an auxiliary port 8a opening downstream of the venturi portion 6 is provided. When the fuel gas is supplied to the auxiliary port 8a through the auxiliary passage 8c provided with the diaphragm valve 8b whose opening is controlled based on the differential pressure between the upstream and downstream of the intake throttle valve 7, Since the fuel replenishment flow rate can be uniquely determined based on the differential pressure between the upstream and downstream of the intake throttle valve 7, which is one of the indicators of the load, the advantage that the control device can be simplified is provided. is there.

【0017】ところで、リーンバーン方式のガスエンジ
ンの排気中に含まれるHCなどをより低減するために、
前記のように酸化触媒を充填した触媒コンバータを排気
通路に設けることがある。また、このような触媒コンバ
ータは、酸化触媒の温度が低下すると充分な活性が得ら
れず、HCなどの除去効果が低下する。
Incidentally, in order to further reduce HC and the like contained in the exhaust gas of the lean burn type gas engine,
As described above, the catalytic converter filled with the oxidation catalyst may be provided in the exhaust passage. Further, in such a catalytic converter, when the temperature of the oxidation catalyst decreases, sufficient activity cannot be obtained, and the effect of removing HC and the like decreases.

【0018】しかしながら、このように酸化触媒を設け
て排気中のHCなどを浄化処理するようにした場合は、
例えば図4に示したように、酸化触媒17を充填した触
媒コンバータ18の直上流部の排気通路19と燃料ガス
の供給タンク20を結ぶ供給通路21を設ける。そし
て、触媒コンバータ18に取り付けた温度センサ22に
接続した制御装置23で制御される電磁弁24を前記供
給通路21に設けることにより、エンジン1の運転中で
あるにも拘らず触媒コンバータ18の温度が予め定めた
値より低くなったときに電磁弁24を開弁作動させて排
気中に燃料ガスを供給すればよい。25は圧力レギュレ
ータである。
However, when an oxidation catalyst is provided to purify HC and the like in exhaust gas,
For example, as shown in FIG. 4, a supply passage 21 is provided that connects an exhaust passage 19 immediately upstream of a catalytic converter 18 filled with an oxidation catalyst 17 and a fuel gas supply tank 20. By providing an electromagnetic valve 24 controlled by a control device 23 connected to a temperature sensor 22 attached to the catalytic converter 18 in the supply passage 21, the temperature of the catalytic converter 18 can be maintained regardless of the operation of the engine 1. When the pressure becomes lower than a predetermined value, the solenoid valve 24 is opened to supply the fuel gas into the exhaust gas. 25 is a pressure regulator.

【0019】かかる構成になる排気の浄化システムにお
いて、エンジン1が例えば低負荷域で連続運転されて酸
化触媒17の温度が例えば500℃より低下すると、そ
の活性が損なわれる可能性が高くなる。ところが、この
ように酸化触媒17の温度が低下したときは、制御装置
23からの信号で電磁弁24を開弁作動させて排気中に
燃料ガスを供給する。
In the exhaust gas purification system having such a configuration, if the temperature of the oxidation catalyst 17 drops below, for example, 500 ° C. when the engine 1 is continuously operated in, for example, a low load range, the activity of the oxidation catalyst 17 is likely to be impaired. However, when the temperature of the oxidation catalyst 17 decreases, the solenoid valve 24 is opened by a signal from the control device 23 to supply the fuel gas into the exhaust gas.

【0020】すると、燃料ガスの供給により排気中に含
まれるHCなどの濃度が高くなって酸化触媒17による
酸化作用が活発に行われる。従って、燃料ガスの供給に
同期して触媒17の温度が活性温度まで上昇するため
に、前記の場合と同様に酸化触媒17の表面に付着した
硫黄あるいはリンなどの酸化被膜の還元作用が行われる
とともに、触媒の活性が維持される。
Then, the concentration of HC and the like contained in the exhaust gas is increased by the supply of the fuel gas, and the oxidizing action of the oxidizing catalyst 17 is actively performed. Accordingly, since the temperature of the catalyst 17 rises to the activation temperature in synchronization with the supply of the fuel gas, the reduction of the oxide film such as sulfur or phosphorus attached to the surface of the oxidation catalyst 17 is performed in the same manner as described above. At the same time, the activity of the catalyst is maintained.

【0021】また、このような燃料ガスの供給は酸化触
媒17の温度が例えば600℃になるまで継続される。
このために、少なくともエンジン1の運転中は酸化触媒
17の温度が活性範囲内に保たれて活性が維持され、排
気中に含まれるHCなどが効率よく除去される。
The supply of the fuel gas is continued until the temperature of the oxidation catalyst 17 reaches, for example, 600.degree.
Therefore, at least during the operation of the engine 1, the temperature of the oxidation catalyst 17 is maintained within the activation range, the activity is maintained, and HC contained in the exhaust gas is efficiently removed.

【0022】一方、このように排気中のHCの除去作用
を行う酸化触媒は次第に劣化して活性を失うために、交
換する必要性がある。しかしながら、酸化触媒17の劣
化は単に経時的要素のみによるものではないために、定
期的な交換を行うことは必ずしも適当ではない。
On the other hand, the oxidation catalyst for removing HC in the exhaust gas gradually deteriorates and loses its activity, and thus needs to be replaced. However, since the deterioration of the oxidation catalyst 17 is not merely due to the time-dependent factor, it is not always appropriate to perform the periodic replacement.

【0023】かかる不具合を解消するためには、例えば
図5に示した実施形態のように温度センサ22による酸
化触媒の温度上昇率を監視する監視回路26を制御装置
23に設け、この監視回路26に警告灯27などを接続
する。そして、電磁弁25の開弁による燃料ガスの供給
時における酸化触媒17の温度上昇率が例えば当初の1
/2以下になったときは酸化触媒17の劣化が進んでい
ると判断し、監視回路26から警告灯27などに作動信
号を供給して該警告灯27を点灯させることにより、運
転者に酸化触媒17の交換を促すようにしている。
In order to solve such a problem, for example, a monitoring circuit 26 for monitoring the temperature rise rate of the oxidation catalyst by the temperature sensor 22 is provided in the control device 23 as in the embodiment shown in FIG. Is connected with a warning light 27 or the like. The rate of temperature rise of the oxidation catalyst 17 when the fuel gas is supplied by opening the solenoid valve 25 is, for example, 1 at the beginning.
When the value falls to / 2 or less, it is determined that the oxidation catalyst 17 is deteriorating, and an operation signal is supplied from the monitoring circuit 26 to the warning light 27 and the like, and the warning light 27 is turned on. The replacement of the catalyst 17 is encouraged.

【0024】従って本実施形態によれば、酸化触媒17
を定期的に交換する必要性がなく、劣化の度合に応じた
最適時期に酸化触媒17を交換することができるため
に、排気の浄化性能を低下させることなく触媒コンバー
タ18の維持費を低減することができる。
Therefore, according to the present embodiment, the oxidation catalyst 17
There is no need to periodically replace the catalyst, and the oxidation catalyst 17 can be replaced at an optimal time according to the degree of deterioration, so that the maintenance cost of the catalytic converter 18 can be reduced without lowering the exhaust gas purification performance. be able to.

【0025】[0025]

【発明の効果】以上の説明から明らかなように本発明
は、エンジンが低負荷域で運転されたときに燃料ガスを
補充供給する補助供給手段を設けたものであるから、ミ
キサにより生成される希薄混合気の空燃比を高負荷域で
の運転に適合させて燃費の改善効果とNOxの低減を行
ったリーン方式のガスエンジンであっても、低負荷域で
空燃比が薄くなり過ぎることを回避することができるた
めに、出力性能および燃焼の安定性を犠牲にすることな
く燃費および排ガス特性などを改善することができる。
As is apparent from the above description, the present invention is provided with the auxiliary supply means for replenishing and supplying the fuel gas when the engine is operated in the low load range, so that it is generated by the mixer. Even with a lean-type gas engine in which the air-fuel ratio of a lean mixture is adapted for operation in a high-load region to improve fuel efficiency and reduce NOx, the air-fuel ratio becomes too low in a low-load region. As a result, fuel economy and exhaust gas characteristics can be improved without sacrificing output performance and combustion stability.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明に係るミキサの空燃比制御装置を備えた
ガスエンジンの概略構成図である。
FIG. 1 is a schematic configuration diagram of a gas engine provided with a mixer air-fuel ratio control device according to the present invention.

【図2】ミキサによる燃料ガスの供給特性図である。FIG. 2 is a characteristic diagram of fuel gas supply by a mixer.

【図3】本発明に係るミキサの空燃比制御装置の変形例
を示す概略断面図である。
FIG. 3 is a schematic sectional view showing a modification of the air-fuel ratio control device for a mixer according to the present invention.

【図4】本発明に係るミキサを備えたガスエンジンの排
気浄化システムを例示する概略構成図である。
FIG. 4 is a schematic configuration diagram illustrating an exhaust gas purification system for a gas engine including a mixer according to the present invention.

【図5】図4に示した排気浄化システムの変形例を示す
会社区構成図である。
FIG. 5 is a configuration diagram of a company section showing a modified example of the exhaust gas purification system shown in FIG. 4;

【符号の説明】[Explanation of symbols]

1 ガスエンジン本体 2 ガスレギュレータ 3 調量弁 4 ミキサ 5 吸気通路 6 ベンチュリ部 6a メインポート 6b アイドルポート 7 吸気絞り弁 8 ガスインジェクタ 8a 補助ポート 8b ダイヤフラムバルブ 8c 補助通路 9 ガスパイプ 10 エキゾーストマニホールド 11 酸素センサ 12 インテークマニホールド 13 吸気圧センサ 14 回転センサ 15 絞り弁開度センサ 16 コントロールユニット 17 酸化触媒 18 触媒コンバータ 19 排気通路 20 燃料ガスの供給タンク 21 供給通路 22 温度センサ 23 制御装置 24 電磁弁 25 圧力レギュレータ 26 監視回路 27 警告灯 DESCRIPTION OF SYMBOLS 1 Gas engine main body 2 Gas regulator 3 Metering valve 4 Mixer 5 Intake passage 6 Venturi section 6a Main port 6b Idle port 7 Intake throttle valve 8 Gas injector 8a Auxiliary port 8b Diaphragm valve 8c Auxiliary passage 9 Gas pipe 10 Exhaust manifold 11 Oxygen sensor Intake manifold 13 intake pressure sensor 14 rotation sensor 15 throttle valve opening sensor 16 control unit 17 oxidation catalyst 18 catalytic converter 19 exhaust passage 20 fuel gas supply tank 21 supply passage 22 temperature sensor 23 controller 24 solenoid valve 25 pressure regulator 26 monitoring Circuit 27 Warning light

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 FI テーマコート゛(参考) F02D 41/02 330 F02D 41/02 330K 41/04 330 41/04 330E Fターム(参考) 3G092 AA05 AA09 AB08 BB01 DC15 DE04S DE09S EA01 EA05 EA06 FA17 FA24 GA05 HA05Z HA06Z HD02X HD02Z HD05Z HE01Z 3G301 HA01 HA15 HA22 JA01 JA02 JA21 JA25 JA26 KA08 KA09 LB00 LB05 LB06 LB09 MA01 MA13 NB02 NB06 NE13 NE15 PA07Z PA11Z PD12Z PE01Z──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) F02D 41/02 330 F02D 41/02 330K 41/04 330 41/04 330E F-term (Reference) 3G092 AA05 AA09 AB08 BB01 DC15 DE04S DE09S EA01 EA05 EA06 FA17 FA24 GA05 HA05Z HA06Z HD02X HD02Z HD05Z HE01Z 3G301 HA01 HA15 HA22 JA01 JA02 JA21 JA25 JA26 KA08 KA09 LB00 LB05 LB06 LB09 MA01 MA13 NB02 NB06 NE13 NE15 PA07

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 吸気通路に設けたベンチュリ部に燃料ガ
スを流出させることにより、理論空燃比より燃料の割合
が少ない希薄混合気を生成して燃焼室に供給するように
したリーンバーン方式のガスエンジン用ミキサにおい
て、ガスエンジンの低負荷域において前記ベンチュリ部
より下流の吸気通路に燃料ガスを供給する補助供給手段
を設けたことを特徴とするミキサの空燃比制御装置。
1. A lean burn type gas in which a fuel gas is caused to flow out to a venturi portion provided in an intake passage to generate a lean mixture having a smaller fuel ratio than a stoichiometric air-fuel ratio and supply the mixture to a combustion chamber. An air-fuel ratio control device for an engine mixer, wherein an auxiliary supply means for supplying fuel gas to an intake passage downstream of the venturi section in a low load region of the gas engine is provided.
【請求項2】 補助供給手段を介して供給される燃料ガ
スの流量は、ガスエンジンの運転状態もしくは吸気絞り
弁の上下流間の差圧に基づいて可変制御されるものであ
ることを特徴とする請求項1に記載の空燃比制御装置。
2. The method according to claim 1, wherein a flow rate of the fuel gas supplied through the auxiliary supply means is variably controlled based on an operation state of the gas engine or a differential pressure between the upstream and downstream of the intake throttle valve. The air-fuel ratio control device according to claim 1, wherein
JP17070599A 1999-06-17 1999-06-17 Mixer air-fuel ratio control device Expired - Fee Related JP3919974B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17070599A JP3919974B2 (en) 1999-06-17 1999-06-17 Mixer air-fuel ratio control device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17070599A JP3919974B2 (en) 1999-06-17 1999-06-17 Mixer air-fuel ratio control device

Publications (2)

Publication Number Publication Date
JP2001003814A true JP2001003814A (en) 2001-01-09
JP3919974B2 JP3919974B2 (en) 2007-05-30

Family

ID=15909876

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17070599A Expired - Fee Related JP3919974B2 (en) 1999-06-17 1999-06-17 Mixer air-fuel ratio control device

Country Status (1)

Country Link
JP (1) JP3919974B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015132206A (en) * 2014-01-14 2015-07-23 三菱重工業株式会社 Gas engine controller, gas engine control method, and gas engine equipped with controller

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015132206A (en) * 2014-01-14 2015-07-23 三菱重工業株式会社 Gas engine controller, gas engine control method, and gas engine equipped with controller
WO2015107753A1 (en) * 2014-01-14 2015-07-23 三菱重工業株式会社 Control device and control method for gas engine and gas engine equipped with control device

Also Published As

Publication number Publication date
JP3919974B2 (en) 2007-05-30

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