JP6508709B2 - Air-fuel ratio control device for gas engine and ship equipped with gas engine with air-fuel ratio control device - Google Patents
Air-fuel ratio control device for gas engine and ship equipped with gas engine with air-fuel ratio control device Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
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- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
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Description
本発明は、燃料ガスと空気とを混合して燃焼させ動力を得るガスエンジンの空燃比制御装置、及び空燃比制御装置付きガスエンジンを搭載した船舶に関する。 The present invention relates to an air-fuel ratio control device for a gas engine that mixes and burns fuel gas and air to obtain power, and a ship equipped with a gas engine with an air-fuel ratio control device.
燃料ガスと空気とを混合して燃焼させ動力を得るガスエンジンは環境に優しく、熱効率が高く、経済的であるため、コジェネレーションプラントの原動機として多く使用されており、また、環境規制が厳しくなってきている船舶においてもガスエンジンが搭載され始めている。しかしながらガスエンジン、特に希薄燃焼ガスエンジンは負荷変動に弱く、特に船舶のエンジンとして使用する場合は、海が荒れることなどによる負荷変動に対処するため数多くの制御装置を設けて空燃比制御を行っている。 A gas engine that mixes fuel gas and air and burns to obtain power is environmentally friendly, high in thermal efficiency, and economical, so it is often used as a prime mover for cogeneration plants, and environmental regulations are becoming stricter. Gas engines are beginning to be installed on even the emerging ships. However, gas engines, especially lean burn gas engines, are vulnerable to load fluctuations, and particularly when used as ship engines, a number of control devices are provided to perform air-fuel ratio control in order to cope with load fluctuations due to rough seas. There is.
図6は従来の空燃比制御装置の概略構成図、図7は従来の空燃比制御装置のエンジン負荷変動に対する空燃比制御を示す図、図8は空燃比制御の必要性を示す図である。
図8において、縦軸は正味平均有効圧(BMEP)であり、横軸は空気過剰率(理論上必要な空気に対する実際の空気量の比)である。希薄燃焼において、空気過剰率が所望の空気過剰率より小さい場合はノッキングを起こしやすくなり、大きい場合は失火を起こしやすく(エンジンが停止しやすく)なる。正味平均有効圧が高くなるほどノッキングや失火を起こさないための適性な空燃比の範囲が狭くなることが分かる。
従来の空燃比制御装置は、図6に示すように、ガスエンジン100と、タービン210及びコンプレッサー220を有する過給機200とを備える。また、空燃比制御手段300を備え、空燃比制御手段300によって、スロットルバルブ(Throttle valve)310、可変バルブタイミング機構(Variable valve timing)320、可変ノズル(Variable Geometry Turbo )330、燃料供給手段340、排気ガスバイパス経路350、排気ガスバイパス制御弁(Waste gate valve)360が制御される。
空気の量を調整制御するためには、過給機200のコンプレッサー220の出口にスロットルバルブ310を設けて空気供給量を制御すると同時に、過給機200のタービン210側に設けた可変ノズル330の制御、及び排気ガスバイパス制御弁360で余分な排気ガスを逃がす制御が必要である。更に、ガスエンジン100側に設けた吸、排気のタイミングを可変にする可変バルブタイミング機構320で排気エネルギーを調整する必要がある。このような制御によって空燃比制御ができ、舶用に耐える動特性が得られる。
しかしながら、従来の空燃比制御方法では、負荷変動等に対応してエンジンの出力を保持しようと燃料ガスと空気の供給量を変化させる場合において、過給機200よりも燃料供給手段340のほうの応答が速いため、燃料ガスと空気の混合バランスが崩れてしまい、図7に示すように空燃比が変動して燃焼が不安定になってしまう。
FIG. 6 is a schematic block diagram of a conventional air-fuel ratio control device, FIG. 7 is a diagram showing air-fuel ratio control with respect to engine load fluctuation of the conventional air-fuel ratio control device, and FIG. 8 is a diagram showing necessity of air-fuel ratio control.
In FIG. 8, the vertical axis is the net mean effective pressure (BMEP), and the horizontal axis is the excess air ratio (the ratio of the actual amount of air to the theoretically required air). In lean combustion, if the excess air ratio is smaller than the desired excess air ratio, knocking tends to occur, and if the excess air ratio exceeds, the misfire tends to occur (the engine is likely to stop). It can be seen that the higher the net average effective pressure, the narrower the range of an appropriate air-fuel ratio for preventing knocking and misfiring.
The conventional air-fuel ratio control device includes a gas engine 100 and a turbocharger 200 having a turbine 210 and a compressor 220, as shown in FIG. The air fuel ratio control unit 300 includes a throttle valve 310, a variable valve timing mechanism 320, a variable geometry turbo 330, a fuel supply unit 340, and the like. The exhaust gas bypass path 350 and the exhaust gas bypass control valve (Waste gate valve) 360 are controlled.
In order to adjust and control the amount of air, the throttle valve 310 is provided at the outlet of the compressor 220 of the turbocharger 200 to control the air supply amount, and at the same time, the variable nozzle 330 provided on the turbine 210 side of the turbocharger 200. Control and control to release excess exhaust gas with the exhaust gas bypass control valve 360 are necessary. Furthermore, it is necessary to adjust the exhaust energy by means of a variable valve timing mechanism 320 provided on the gas engine 100 side for changing the timing of intake and exhaust. By such control, air-fuel ratio control can be performed, and dynamic characteristics that endure marine use can be obtained.
However, in the conventional air-fuel ratio control method, in the case of changing the supply amount of the fuel gas and the air in order to maintain the output of the engine in response to the load fluctuation etc. Since the response is fast, the mixing balance of the fuel gas and the air is broken, and as shown in FIG. 7, the air-fuel ratio fluctuates and the combustion becomes unstable.
ここで、特許文献1には、燃料供給通路中の燃料流量の検出値に基づき必要空気量を算出するとともに給気通路における給気圧力及び給気温度の検出値に基づき実空気量を算出し、実空気量が必要空気量に一致するように給気放出手段によって給気通路における給気量を制御する、ガスエンジンの空燃比制御方法が開示されている。
また、特許文献2には、エンジンに供給される燃料ガスの発熱量及びエンジンの始動時を含む運転時の最適熱量に対応する最適燃料ガス量を算出し、最適燃料ガス量と給気圧力検出値及び給気温度検出値に基づき算出された実際の空気量とに適合する過給機の最適回転数を算出し、最適過給機回転数になるように過給機に連結された電動モータを制御するモータコントローラを有してなる、モータ駆動過給機付きガスエンジンが開示されている。
また、特許文献3には、ガスエンジンから検出されたエンジン回転速度信号と、その目標値となる速度指令値信号との偏差に基づき燃料ガス流量指令値を演算し、燃料ガス流量指令値に応じて燃料流量制御バルブの燃料ガス流量を設定する速度制御工程と、燃料ガス流量指令値に対して適正空燃比となる混合気流量指令値を算出し、混合気流量指令値と実混合気流量との偏差に基づきスロットルバルブの目標開度を設定するフィードバック制御を行う空燃比制御工程とを備えたガスエンジンの統合制御方法が開示されている。
また、特許文献4には、給気圧力センサからの給気圧力の検出値及び負荷検出器からのエンジン負荷の検出値に基づき、燃料噴射量を給気圧力及びエンジン負荷にそれぞれ対応する目標燃料噴射量に調整するとともに、過給機回転数検出器あるいは排気圧力センサから入力される過給機回転数あるいは排気圧力の検出値に基づき、燃料噴射量を過給機回転数及び排気圧力のいずれか一方または双方にそれぞれ対応する目標燃料噴射量に調整する制御装置を備える発電用ディーゼルエンジンの燃料制御装置が開示されている。
Here, in Patent Document 1, the required air amount is calculated based on the detected value of the fuel flow rate in the fuel supply passage, and the actual air amount is calculated based on the detected value of the air supply pressure and the air supply temperature in the air supply passage. A method of controlling an air-fuel ratio of a gas engine is disclosed, in which the air supply amount in the air supply passage is controlled by the air supply and release means so that the actual air amount matches the required air amount.
In addition, Patent Document 2 calculates the optimum fuel gas amount and the air supply pressure, by calculating the calorific value of the fuel gas supplied to the engine and the optimum heat amount corresponding to the optimum heat quantity at the time of operation including the start of the engine. The electric motor connected to the supercharger to calculate the optimum number of revolutions of the supercharger that matches the actual air volume calculated based on the value and the air supply temperature detection value, and to achieve the optimum supercharger rotation number A motor driven supercharger gas engine is disclosed which comprises a motor controller controlling the motor.
Further, in Patent Document 3, a fuel gas flow rate command value is calculated based on a deviation between an engine rotational speed signal detected from a gas engine and a speed command value signal serving as a target value thereof, and the fuel gas flow rate command value is calculated. Speed control step of setting the fuel gas flow rate of the fuel flow rate control valve, and calculating a mixed air flow amount command value to be an appropriate air fuel ratio with respect to the fuel gas flow rate command value; An air-fuel ratio control step of performing feedback control to set a target opening degree of a throttle valve based on the deviation of the above is disclosed.
Further, in Patent Document 4, a target fuel corresponding to each of the air supply pressure and the engine load is a fuel injection amount based on the detected value of the air supply pressure from the air supply pressure sensor and the detected value of the engine load from the load detector. The fuel injection amount is adjusted to either the turbocharger rotational speed or the exhaust pressure based on the detected value of the turbocharger rotational speed or the exhaust pressure input from the turbocharger rotational speed detector or the exhaust pressure sensor while adjusting to the injection amount. A fuel control device for a diesel engine for power generation is disclosed that includes a control device that adjusts the target fuel injection amount corresponding to one or both of them.
ガスエンジン、特に希薄燃焼ガスエンジンがノッキングや失火を起こさず安定して燃焼するためには、負荷が変動した場合など燃料ガスの供給量の設定変更がされた場合であっても、空燃比を一定に制御する必要がある。しかしながら、空燃比を制御するための機器を多く追加しても応答性をはじめとする制御性の向上を図ることは難しく、機器点数が増え複雑になることにより信頼性の低下も招き易い。
特許文献1のガスエンジンの空燃比制御方法は、燃料流量、給気圧力及び給気温度を検出して必要空気量及び実空気量を算出する必要があるとともに、給気通路中の給気の一部を外部に放出するための給気放出手段等を必要とするものである。
また、特許文献2のモータ駆動過給機付きガスエンジンは、最適燃料ガス量を算出し、給気圧力及び給気温度を検出して過給機の最適回転数を算出して電動モータを制御するモータコントローラを必要とするものであるが、空燃比を制御するための機器の応答性を考慮して制御を行うものではないため、負荷変動時に空燃比を一定に保つことが難しい。
また、特許文献3のガスエンジンの制御方法は、検出したエンジン回転速度に基づいて各演算を行い、スロットルバルブの目標開度を設定するフィードバック制御を必要とするものであるが、過給機の応答性を考慮して制御を行うものではないため負荷変動時に空燃比を一定に保つことが難しい。
また、特許文献4の発電用ディーゼルエンジンの燃料制御装置は、給気圧力、エンジン負荷、過給機回転数、及び排気圧力など複数の検出値を制御に用いるものであるが、燃料―空気制御系における適度な応答性を保持するものであり、過給機の応答性を考慮して制御を行うものではないため、負荷変動時に空燃比を一定に保つことが難しい。また、発電用ディーゼルエンジンに関する制御装置であり、ディーゼルエンジンよりも細かい制御が求められるガスエンジンに関するものではない。
In order to stably burn a gas engine, especially a lean combustion gas engine without knocking or misfiring, the air fuel ratio should be set even if the setting of the amount of fuel gas supplied is changed, such as when the load fluctuates. It is necessary to control it regularly. However, it is difficult to improve the controllability such as responsiveness even if many devices for controlling the air-fuel ratio are added, and the number of devices increases and the reliability tends to be reduced due to the complexity.
In the air-fuel ratio control method of the gas engine of Patent Document 1, it is necessary to detect the fuel flow rate, the air supply pressure and the air supply temperature to calculate the required air amount and the actual air amount. It requires an air supply and discharge means for discharging a part to the outside.
Moreover, the gas engine with a motor drive supercharger of patent document 2 calculates the optimal fuel gas amount, detects the air supply pressure and the air supply temperature, calculates the optimal number of revolutions of the supercharger, and controls the electric motor. It is difficult to keep the air-fuel ratio constant at the time of load fluctuation since the control is not performed in consideration of the responsiveness of the device for controlling the air-fuel ratio.
Moreover, the control method of the gas engine of Patent Document 3 requires feedback control to perform each calculation based on the detected engine rotational speed and set a target opening degree of the throttle valve. Since control is not performed in consideration of responsiveness, it is difficult to keep the air-fuel ratio constant at load fluctuation.
Moreover, although the fuel control apparatus of the diesel engine for electric power generation of patent document 4 uses several detection values, such as an air supply pressure, an engine load, supercharger rotation speed, and an exhaust pressure, for control, fuel-air control is carried out. It is difficult to keep the air-fuel ratio constant at the time of load fluctuation because it is intended to maintain appropriate responsiveness in the system and to perform control in consideration of the responsiveness of the turbocharger. Moreover, it is a control device related to a diesel engine for power generation, and does not relate to a gas engine that requires finer control than the diesel engine.
そこで本発明は、空燃比を制御するための機器を多く追加することなく、負荷が変動した場合など燃料ガスの燃料供給量の設定変更がされた場合であっても、空燃比を一定に保つことができる応答性に優れたガスエンジンの空燃比制御装置及び空燃比制御装置付きガスエンジンを搭載した船舶を提供することを目的とする。 Therefore, the present invention keeps the air-fuel ratio constant even if the setting of the fuel supply amount of the fuel gas is changed, for example, when the load fluctuates without adding a large number of devices for controlling the air-fuel ratio. It is an object of the present invention to provide an air-fuel ratio control device of a gas engine excellent in responsiveness and a ship equipped with the gas engine with the air-fuel ratio control device.
請求項1記載に対応したガスエンジンの空燃比制御装置においては、燃料ガスと空気とを混合して燃焼させ動力を得るガスエンジンの空燃比制御装置であって、ガスエンジンへ供給する燃料ガスの燃料供給量を制御する燃料供給量制御手段と、空気を加圧するコンプレッサー及びガスエンジンの排気ガスにより駆動されるタービンを有した過給機と、過給機の回転数を検出する過給機回転数検出手段と、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて必要空気量に到達するまでの空気供給量の増加速度又は減少速度を求めて、適正空燃比を維持する燃料供給量の増加速度又は減少速度を求め、燃料供給量の増加速度又は減少速度に基づいて、過給機よりも応答の速い燃料供給量制御手段による燃料ガスの燃料供給量の時間的変化を遅くするように制御する空燃比制御手段とを備えたことを特徴とする。
負荷が変動した場合には、過給機の応答が遅れるが、燃料供給量制御手段は過給機よりも応答が速いので、負荷変動が生じた場合など燃料ガスの燃料供給量の設定が変更された際は、空気供給量よりも燃料ガスの燃料供給量のほうが先に必要量に到達するため空燃比が変動して燃焼が不安定になってしまう。そこで、請求項1に記載の本発明によれば、過給機の回転数に基づいて燃料ガスの燃料供給量の時間的変化を燃料供給量制御手段にて遅くする、即ち燃料ガスの燃料供給量が必要量に到達するまでの時間を空気供給量に合わせて遅くすることで、空燃比を制御する機器を多く増やすことなく空燃比を一定にして、ガスエンジンにおける燃焼を安定させることができる。
An air-fuel ratio control apparatus for a gas engine according to claim 1 is an air-fuel ratio control apparatus for a gas engine which mixes fuel gas and air and burns to obtain power, which is a fuel gas supplied to the gas engine. A supercharger having a fuel supply amount control means for controlling a fuel supply amount, a compressor for pressurizing air and a turbine driven by exhaust gas of a gas engine, and a turbocharger rotation for detecting the number of revolutions of the turbocharger The rate of increase or decrease in the amount of supplied air until the required amount of air is reached based on the detection results of the number of detection means and the change in the fuel supply amount of the fuel gas based on the detection result of the turbocharger rotational speed detection means. seeking, seeking an increase rate or decrease rate of the fuel supply quantity to maintain the proper air-fuel ratio, based on the increase rate or decrease rate of the fuel supply quantity, fuel by fast fuel supply amount controller responsive the supercharger Characterized by comprising a air-fuel ratio control means for controlling so as to slow down the change over time in fuel supply flow rate of the gas.
When the load fluctuates, the response of the supercharger is delayed, but the response of the fuel supply control means is faster than that of the supercharger. Therefore, the setting of the fuel supply of the fuel gas is changed when the load fluctuates. when it is, the air-fuel ratio for better fuel supply amount of the fuel gas than air bellflower supply amount reaches the required amount earlier combustion fluctuates becomes unstable. Therefore, according to the present invention as set forth in claim 1, the fuel supply amount control means delays the temporal change of the fuel supply amount of the fuel gas based on the number of revolutions of the turbocharger, that is, the fuel supply of the fuel gas by slower timed until the amount reaches a required amount of air bellflower feed amount, and the air-fuel ratio without increasing much the device for controlling the air-fuel ratio constant, stabilizing the combustion in the gas engine Can.
請求項2記載の本発明は、燃料供給量制御手段が、デジタル的にオン/オフするソレノイド弁であることを特徴とする。請求項2に記載の本発明によれば、燃料供給量制御手段に一般的なオン/オフ型のソレノイド弁を使用することで、燃料供給量制御手段を複雑にすることなく安価に、また信頼性も高く構成することができる。 The present invention according to claim 2 is characterized in that the fuel supply amount control means is a solenoid valve which is turned on / off digitally. According to the second aspect of the present invention, by using a general on / off type solenoid valve as the fuel supply amount control means, the fuel supply amount control means is not complicated and can be made inexpensive and reliable. Sex can also be configured highly.
請求項3記載の本発明は、空燃比制御手段が、ソレノイド弁のデューティー比を制御することを特徴とする。請求項3に記載の本発明によれば、ソレノイド弁のデューティー比を制御することによって、燃料供給量制御手段による燃料ガスの燃料供給量の制御が自由にでき、時間的変化を遅くすることができる。 The present invention according to claim 3 is characterized in that the air-fuel ratio control means controls the duty ratio of the solenoid valve. According to the present invention described in claim 3, by controlling the duty ratio of the solenoid valve, control of the fuel supply amount of the fuel gas by the fuel supply amount control means can freely be slow temporal change it can.
請求項4記載の本発明は、ガスエンジンのエンジン回転数を検出するエンジン回転数検出手段を備え、空燃比制御手段は、エンジン回転数検出手段の検出結果に基づいて制御を行うことを特徴とする。請求項4に記載の本発明によれば、エンジンの回転数を考慮してガス流量を算出することができるので、空燃比制御手段は、より正確なガス流量に基づいて燃料ガスの燃料供給量の時間的変化を制御することができる。 According to a fourth aspect of the present invention, the engine rotational speed detecting means for detecting the engine rotational speed of the gas engine is provided, and the air fuel ratio control means performs control based on the detection result of the engine rotational speed detection means. Do. According to the present invention described in claim 4, it is possible to calculate the gas flow rate in consideration of the rotational speed of the engine, the air-fuel ratio control means, the fuel supply amount of the fuel gas based on a more accurate gas flow rate Control over time.
請求項5記載の本発明は、過給機を加勢する加勢手段を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて加勢手段を制御することを特徴とする。請求項5に記載の本発明によれば、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、加勢手段により過給機を加勢することで過給機の回転数を上げて必要空気量を速く確保することができる。 According to a fifth aspect of the present invention, the air-fuel ratio control means is provided with an energizing means for energizing the supercharger, and the air-fuel ratio control means detects the detection result of the supercharger rotational speed detecting means when the setting of the fuel supply amount of the fuel gas is changed. And controlling the biasing means on the basis of. According to the fifth aspect of the present invention, for example, in the case where the number of revolutions of the turbocharger is lower than the required number of revolutions, that is, when the air supply amount is insufficient, the supercharging is performed by the booster. The number of revolutions of the machine can be increased to ensure the required amount of air quickly.
請求項6記載の本発明は、加勢手段は、過給機を駆動するとともに過給機により回転され発電を行う機能を有したモータ/ジェネレータであることを特徴とする。請求項6に記載の本発明によれば、過給機の回転数が必要回転数より低い場合つまり空気供給量が不足している場合には、過給機を加勢するモータとして使用して過給機の回転数を上げて必要空気量を確保し、過給機の回転数が必要回転数より高い場合つまり空気供給量が過多の場合には、ジェネレータとして発電することで過給機の回転を抑えて空気供給量を減らすことができる。 The invention according to claim 6 is characterized in that the energizing means is a motor / generator having a function of driving the supercharger and rotating by the supercharger to generate power. According to the present invention as set forth in claim 6, when the number of revolutions of the turbocharger is lower than the required number of revolutions, that is, when the amount of supplied air is insufficient, the use of the turbocharger as a motor for energizing is excessive. Increase the number of revolutions of the feeder to secure the required amount of air, and if the number of revolutions of the turbocharger is higher than the required number of revolutions, that is, if the amount of air supply is excessive, rotate the turbocharger by generating power as a generator. Can reduce the amount of air supply.
請求項7記載の本発明は、過給機のコンプレッサーとガスエンジンの間の経路にスロットル弁を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいてスロットル弁を制御することを特徴とする。請求項7に記載の本発明によれば、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、応答の速いスロットル弁を開けることで空気供給量を速く増やすことができる。 According to a seventh aspect of the present invention, the throttle valve is provided in the path between the compressor of the turbocharger and the gas engine, and the air fuel ratio control means changes the setting of the fuel supply amount of the fuel gas. The throttle valve is controlled based on the detection result of the rotational speed detection means. According to the seventh aspect of the present invention, for example, when the number of revolutions of the turbocharger is lower than the required number of revolutions, that is, when the amount of supplied air is insufficient, the amount of supplied air can be increased by opening the fast response throttle valve. It can be increased quickly.
請求項8記載の本発明は、空燃比制御手段は、スロットル弁を定常負荷時は絞った位置に臨ませる制御をすることを特徴とする。請求項8に記載の本発明によれば、定常負荷時にはスロットル弁を絞っておくことによって、負荷上昇時に備えて余力を持たせることができる。 The present invention according to claim 8 is characterized in that the air-fuel ratio control means controls the throttle valve to be in a throttled position during steady load. According to the present invention as set forth in claim 8, by throttling the throttle valve at the time of steady load, it is possible to provide extra capacity at the time of load rise.
請求項9記載の本発明は、過給機のタービンの上流側に可変ノズルを備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて可変ノズルを制御することを特徴とする。請求項9に記載の本発明によれば、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、応答の速い可変ノズルのノズル翼の向きや角度によって排気ガス通路を変化させてガスエンジンから供給される排気ガスの流速を調整して加圧空気の加圧特性を改善し、空気供給量を速く増やすことができ、空燃比を一定に保ち易くなる。 According to a ninth aspect of the present invention, the variable nozzle is provided on the upstream side of the turbine of the supercharger, and the air-fuel ratio control means detects the supercharger rotational speed when the setting of the fuel supply amount of the fuel gas is changed. The variable nozzle is controlled based on the detection result of According to the present invention, for example, when the number of revolutions of the supercharger is lower than the required number of revolutions, that is, when the amount of supplied air is insufficient, the direction or angle of the nozzle blade of the variable nozzle having quick response By changing the exhaust gas passage to adjust the flow velocity of the exhaust gas supplied from the gas engine, the pressurization characteristic of pressurized air can be improved, the amount of supplied air can be increased quickly, and the air-fuel ratio can be easily maintained constant. .
請求項10記載の本発明は、過給機のタービンを迂回するバイパス経路と、バイパス経路を開閉するバイパス制御弁を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいてバイパス制御弁を制御することを特徴とする。請求項10に記載の本発明によれば、過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、予め開けてあるバイパス経路の開度を応答の速いバイパス制御弁で絞り過給機の回転数を増し空気供給量を速く増やすことができる。また、過給機の回転数が必要回転数より大きい場合には、バイパス制御弁を開いてバイパス経路に排気ガスを流してタービンを迂回させることで過給機の回転数を下げて空気供給量を速く減少させることができる。 The present invention according to claim 10 includes a bypass path bypassing a turbine of a turbocharger and a bypass control valve opening and closing the bypass path, and the air-fuel ratio control means changes the setting of the fuel supply amount of fuel gas. In this case, the bypass control valve is controlled based on the detection result of the turbocharger rotational speed detection means. According to the present invention as set forth in claim 10, when the number of revolutions of the turbocharger is lower than the required number of revolutions, that is, when the air supply amount is insufficient, the opening degree of the bypass path opened in advance is bypassed with quick response. The control valve can increase the number of revolutions of the throttling turbocharger to rapidly increase the air supply amount. Also, if the rotational speed of the turbocharger is higher than the required rotational speed, the bypass control valve is opened to flow the exhaust gas in the bypass path to bypass the turbine to reduce the rotational speed of the turbocharger to reduce the air supply amount. Can be reduced quickly.
請求項11記載の本発明は、ガスエンジンにより駆動される可変ピッチプロペラを備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて可変ピッチプロペラを制御することを特徴とする。請求項11に記載の本発明によれば、応答の速い可変ピッチプロペラのピッチを変えてガスエンジンにかかる負荷を増減することで、空燃比を一定に保ち易くできる。 The present invention according to claim 11 includes a variable pitch propeller driven by a gas engine, and the air-fuel ratio control means detects the rotational speed of the turbocharger when the setting of the fuel supply amount of the fuel gas is changed. The variable pitch propeller is controlled based on the result. According to the eleventh aspect of the present invention, the air-fuel ratio can be easily kept constant by changing the pitch of the quick response variable pitch propeller to increase or decrease the load applied to the gas engine.
請求項12記載に対応した空燃比制御装置付きガスエンジンを搭載した船舶においては、請求項1から請求項11のうちの1項に記載のガスエンジンの空燃比制御装置を備えたことを特徴とする。請求項12に記載の本発明によれば、過給機の回転数に基づいて燃料ガスの燃料供給量の時間的変化を燃料供給量制御手段にて遅くする、即ち燃料ガスの燃料供給量が必要量に到達するまでの時間を空気供給量に合わせて遅くすることで、空燃比を制御する機器を多く増やすことなく空燃比を一定にして、ガスエンジンにおける燃焼を安定させることができる空燃比制御装置付きのガスエンジンを搭載した船舶を提供することができる。 A ship equipped with a gas engine equipped with an air-fuel ratio control device according to claim 12 is characterized in that the air-fuel ratio control device for a gas engine according to any one of claims 1 to 11 is provided. Do. According to the present invention as set forth in claim 12, the fuel supply amount control means delays the temporal change of the fuel supply amount of the fuel gas based on the rotational speed of the supercharger, that is, the fuel supply amount of the fuel gas by slower timed to reach the required amount of air bellflower supply amount can be an air-fuel ratio without increasing much the device for controlling the air-fuel ratio constant, to stabilize the combustion in the gas engine It is possible to provide a ship equipped with a gas engine with an air-fuel ratio control device.
本発明によれば、過給機の回転数に基づいて燃料ガスの燃料供給量の時間的変化を燃料供給量制御手段にて遅くする、即ち燃料ガスの燃料供給量が必要量に到達するまでの時間を空気供給量に合わせて遅くすることで、空燃比を制御する機器を多く増やすことなく空燃比を一定にして、ガスエンジンにおける燃焼を安定させることができる。 According to the present invention, the fuel supply amount control means delays the temporal change of the fuel supply amount of the fuel gas based on the rotational speed of the turbocharger, that is, until the fuel supply amount of the fuel gas reaches the required amount. the time that slow to suit the sky bellflower feed amount, and the air-fuel ratio without increasing much the device for controlling the air-fuel ratio constant, it is possible to stabilize the combustion in a gas engine.
また、燃料供給量制御手段が、デジタル的にオン/オフするソレノイド弁である場合には、燃料供給量制御手段に一般的なオン/オフ型のソレノイド弁を使用することで、燃料供給量制御手段を複雑にすることなく安価に、また信頼性も高く構成することができる。 In addition, when the fuel supply amount control means is a solenoid valve that turns on / off digitally, the fuel supply amount control means is controlled by using a general on / off type solenoid valve as the fuel supply amount control means. It can be configured inexpensively and highly reliably without making the means complicated.
また、空燃比制御手段が、ソレノイド弁のデューティー比を制御する場合には、ソレノイド弁のデューティー比を制御することによって、燃料供給量制御手段による燃料ガスの燃料供給量の制御が自由にでき、時間的変化を遅くすることができる。 Further, the air-fuel ratio control means, when controlling the duty ratio of the solenoid valve, by controlling the duty ratio of the solenoid valve, control of the fuel supply amount of the fuel gas by the fuel supply amount control means can be freely, Temporal change can be delayed.
また、ガスエンジンのエンジン回転数を検出するエンジン回転数検出手段を備え、空燃比制御手段は、エンジン回転数検出手段の検出結果に基づいて制御を行う場合には、エンジンの回転数を考慮してガス流量を算出することができるので、空燃比制御手段は、より正確なガス流量に基づいて燃料ガスの燃料供給量の時間的変化を制御することができる。 In addition, the engine rotational speed detecting means for detecting the engine rotational speed of the gas engine is provided, and the air fuel ratio control means takes into consideration the engine rotational speed when performing control based on the detection result of the engine rotational speed detecting means. Since the gas flow rate can be calculated, the air-fuel ratio control means can control the temporal change of the fuel supply amount of the fuel gas based on the more accurate gas flow rate.
また、過給機を加勢する加勢手段を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて加勢手段を制御する場合には、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、加勢手段により過給機を加勢することで過給機の回転数を上げて必要空気量を速く確保することができる。 The air-fuel ratio control means controls the energizing means based on the detection result of the turbocharger rotational speed detecting means when the setting of the fuel supply amount of the fuel gas is changed. In the case where the number of revolutions of the supercharger is lower than the required number of revolutions, that is, when the air supply amount is insufficient, for example, the number of revolutions of the supercharger is increased by energizing the supercharger by the adder. The required amount of air can be secured quickly.
また、加勢手段は、過給機を駆動するとともに過給機により回転され発電を行う機能を有したモータ/ジェネレータである場合には、過給機の回転数が必要回転数より低い場合つまり空気供給量が不足している場合には、過給機を加勢するモータとして使用して過給機の回転数を上げて必要空気量を確保し、過給機の回転数が必要回転数より高い場合つまり空気供給量が過多の場合には、ジェネレータとして発電することで過給機の回転を抑えて空気供給量を減らすことができる。 Further, in the case where the energizing means is a motor / generator having a function of driving the supercharger and rotating by the supercharger to generate power, the case where the number of revolutions of the supercharger is lower than the required number of revolutions, that is, air When the amount of supply is insufficient, the turbocharger is used as a motor to boost the number of revolutions of the turbocharger to increase the required amount of air, and the number of revolutions of the turbocharger is higher than the number of revolutions required In the case where the air supply amount is excessive, the power generation as a generator can reduce the air supply amount by suppressing the rotation of the turbocharger.
また、過給機のコンプレッサーとガスエンジンの間の経路にスロットル弁を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいてスロットル弁を制御する場合には、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、応答の速いスロットル弁を開けることで空気供給量を速く増やすことができる。 Further, a throttle valve is provided in a path between the compressor of the turbocharger and the gas engine, and the air-fuel ratio control means detects the detection result of the turbocharger rotation speed detection means when the setting of the fuel supply amount of the fuel gas is changed. In the case of controlling the throttle valve on the basis of, for example, when the number of revolutions of the supercharger is lower than the required number of revolutions, that is, when the air supply amount is insufficient, the air supply amount can be It can be increased quickly.
また、空燃比制御手段は、スロットル弁を定常負荷時は絞った位置に臨ませる制御をする場合には、定常負荷時にはスロットル弁を絞っておくことによって、負荷上昇時に備えて余力を持たせることができる。 Further, when the air-fuel ratio control means performs control to make the throttle valve come to the throttled position during steady load, by throttling the throttle valve at steady load, it is possible to have extra power in preparation for load rise. Can.
また、過給機のタービンの上流側に可変ノズルを備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて可変ノズルを制御する場合には、例えば過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、応答の速い可変ノズルのノズル翼の向きや角度によって排気ガス通路を変化させてガスエンジンから供給される排気ガスの流速を調整して加圧空気の加圧特性を改善し、空気供給量を速く増やすことができ、空燃比を一定に保ち易くなる。 Further, a variable nozzle is provided upstream of the turbine of the turbocharger, and the air-fuel ratio control unit is variable based on the detection result of the turbocharger rotation number detection unit when the setting of the fuel supply amount of the fuel gas is changed. When controlling the nozzles, for example, when the number of revolutions of the turbocharger is lower than the required number of revolutions, that is, when the air supply amount is insufficient, the exhaust gas passage is By changing the flow rate of the exhaust gas supplied from the gas engine by adjusting it, the pressurization characteristic of the pressurized air can be improved, the amount of supplied air can be rapidly increased, and the air-fuel ratio can be easily kept constant.
また、過給機のタービンを迂回するバイパス経路と、バイパス経路を開閉するバイパス制御弁を備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいてバイパス制御弁を制御する場合には、過給機の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、予め開けてあるバイパス経路の開度を応答の速いバイパス制御弁で絞り過給機の回転数を増し空気供給量を速く増やすことができる。また、過給機の回転数が必要回転数より大きい場合には、バイパス制御弁を開いてバイパス経路に排気ガスを流してタービンを迂回させることで過給機の回転数を下げて空気供給量を速く減少させることができる。 In addition, a bypass path bypassing the turbocharger turbine and a bypass control valve opening and closing the bypass path are provided, and the air-fuel ratio control means changes the setting of the fuel supply amount of the fuel gas. When controlling the bypass control valve based on the detection result of the detection means, if the number of revolutions of the supercharger is lower than the required number of revolutions, that is, if the air supply amount is insufficient, the bypass path opened in advance is opened. The quick response bypass control valve can increase the number of revolutions of the squeezer and increase the amount of air supply rapidly. Also, if the rotational speed of the turbocharger is higher than the required rotational speed, the bypass control valve is opened to flow the exhaust gas in the bypass path to bypass the turbine to reduce the rotational speed of the turbocharger to reduce the air supply amount. Can be reduced quickly.
また、ガスエンジンにより駆動される可変ピッチプロペラを備え、空燃比制御手段は、燃料ガスの燃料供給量の設定変更がされた場合に過給機回転数検出手段の検出結果に基づいて可変ピッチプロペラを制御する場合には、応答の速い可変ピッチプロペラのピッチを変えてガスエンジンにかかる負荷を増減することで、空燃比を一定に保ち易くできる。 The air-fuel ratio control means is provided with a variable pitch propeller driven by a gas engine, and the variable pitch propeller is controlled based on the detection result of the turbocharger rotational speed detection means when the setting of the fuel supply amount of the fuel gas is changed. In order to control the air-fuel ratio, it is easy to keep the air-fuel ratio constant by changing the pitch of the variable pitch propeller with quick response to increase or decrease the load applied to the gas engine.
また、請求項1から請求項11のうちの1項に記載のガスエンジンの空燃比制御装置を船舶に備えた場合には、過給機の回転数に基づいて燃料ガスの燃料供給量の時間的変化を燃料供給量制御手段にて遅くする、即ち燃料ガスの燃料供給量が必要量に到達するまでの時間を空気供給量に合わせて遅くすることで、空燃比を制御する機器を多く増やすことなく空燃比を一定にして、ガスエンジンにおける燃焼を安定させることができる空燃比制御装置付きのガスエンジンを搭載した船舶を提供することができる。 Furthermore, when the air-fuel ratio control apparatus for a gas engine according to any one of claims 1 to 11 is provided in a ship, the time of the fuel supply amount of fuel gas based on the number of revolutions of the supercharger changes the slowing in the fuel supply amount control means, i.e. the time until the fuel supply amount of the fuel gas reaches the required amount by slow to suit the sky bellflower supply amount, a device for controlling the air-fuel ratio It is possible to provide a ship equipped with a gas engine equipped with an air-fuel ratio control device capable of stabilizing combustion in the gas engine by making the air-fuel ratio constant without increasing much.
以下に、本発明の実施形態によるガスエンジンの空燃比制御装置、及び空燃比制御装置付きガスエンジンを搭載した船舶について説明する。
図1は本発明の一実施形態による空燃比制御装置付きガスエンジンを搭載した船舶の概略構成図、図2は同ガスエンジンの空燃比制御装置の概略構成図、図3は同空燃比制御装置のエンジン負荷変動に対する空燃比制御を示す図である。
Hereinafter, an air-fuel ratio control device for a gas engine according to an embodiment of the present invention, and a ship equipped with a gas engine with an air-fuel ratio control device will be described.
FIG. 1 is a schematic diagram of a ship equipped with a gas engine with an air-fuel ratio controller according to an embodiment of the present invention, FIG. 2 is a schematic diagram of an air-fuel ratio controller of the gas engine, and FIG. 3 is an air-fuel ratio controller It is a figure which shows the air fuel ratio control with respect to the engine load fluctuation of.
図1に示すように、本実施形態の空燃比制御装置付きガスエンジンを搭載した船舶は、船体1の船尾2側に、プロペラ3を駆動する駆動源4を備えている。
駆動源4は、燃料ガスと空気とを混合して燃焼させ動力を得る希薄燃焼式のガスエンジン10と、過給機20を有する。過給機20は、ガスエンジン10から排気された排気ガスにより駆動され、ガスエンジン10に加圧空気を供給する。
なお、ガスエンジン10は希薄燃焼式以外の超希薄燃焼式や負荷変動時に同様な課題を有する他の方式のガスエンジンであってもよい。
As shown in FIG. 1, the ship equipped with the gas engine with air-fuel ratio control device of the present embodiment is provided with a drive source 4 for driving a propeller 3 on the stern 2 side of the hull 1.
The drive source 4 has a lean burn gas engine 10 that mixes and burns fuel gas and air to obtain power, and a turbocharger 20. The supercharger 20 is driven by the exhaust gas exhausted from the gas engine 10 to supply the gas engine 10 with pressurized air.
The gas engine 10 may be a super lean combustion type other than the lean combustion type, or may be a gas engine of another type having the same problem when the load changes.
次に、図2を用いて同ガスエンジンの空燃比制御装置について説明する。
本実施形態のガスエンジンの空燃比制御装置は、ガスエンジン10へ供給する燃料ガスの供給量を制御する燃料供給量制御手段30と、過給機20の回転数を検出する過給機回転数検出手段31と、空気と燃料ガスとの混合比である空燃比を制御する空燃比制御手段32とを備える。
過給機20は、ガスエンジン10の排気経路に設けられ排ガスにより駆動されるタービン21と、このタービン21によって動作し空気を加圧するコンプレッサー22と、タービン21の上流側(排気ガス導入側)に配置される可変ノズル23とを有する。
可変ノズル23は、ノズル翼の向きや角度によって排気ガス通路を変化させてガスエンジン10から供給される排気ガスの流速を調整して加圧空気の加圧特性を改善することができる。
過給機20からガスエンジン10までの間の経路には空気冷却器(図示無し)を有しており、コンプレッサー22で加圧され高温となった空気は、空気冷却器で冷却されてガスエンジン10に導入される。
燃料供給量制御手段30にはデジタル的にオン/オフするソレノイド弁を用いている。一般的なオン/オフ型のソレノイド弁を用いることで、燃料供給量制御手段30を複雑にすることなく安価に、また信頼性も高く構成することができる。
Next, an air-fuel ratio control device of the same gas engine will be described with reference to FIG.
The air-fuel ratio control device for a gas engine according to the present embodiment includes a fuel supply amount control unit 30 that controls the supply amount of fuel gas supplied to the gas engine 10, and a turbocharger rotation speed that detects the rotational speed of the turbocharger 20. A detection means 31 and an air-fuel ratio control means 32 for controlling an air-fuel ratio which is a mixture ratio of air and fuel gas are provided.
The supercharger 20 includes a turbine 21 provided in an exhaust path of the gas engine 10 and driven by the exhaust gas, a compressor 22 operated by the turbine 21 to pressurize air, and an upstream side (exhaust gas introduction side) of the turbine 21 And a variable nozzle 23 disposed.
The variable nozzle 23 can change the exhaust gas passage depending on the direction and angle of the nozzle blade, adjust the flow velocity of the exhaust gas supplied from the gas engine 10, and improve the pressurization characteristic of the pressurized air.
An air cooler (not shown) is provided in the path from the supercharger 20 to the gas engine 10, and the air pressurized and heated by the compressor 22 is cooled by the air cooler and the gas engine is cooled. It will be introduced in ten.
The fuel supply amount control means 30 uses a solenoid valve which is turned on / off digitally. By using a general on / off type solenoid valve, the fuel supply amount control means 30 can be configured inexpensively and with high reliability without complication.
空燃比制御手段32は、ガバナーの指示変更、負荷変動、又は外乱などによって燃料ガスの供給量が変動する場合、つまり燃料ガスの供給量の設定変更がされた場合に、過給機回転数検出手段31の検出結果に基づいてソレノイド弁30のデューティー比を制御することによって、ソレノイド弁30による燃料ガスの供給量の制御が自由にでき、時間的変化を遅くすることができる。
すなわち、ガスエンジン10に係る負荷が増加又は減少した場合には、ガスエンジン10の回転数を維持するために、空気供給量及びガス燃料供給量が増加又は減少するように制御される。その制御において、まず、検出した過給機20の回転数から実際の空気供給量を算出し、必要空気量に到達するまでの空気供給量の増加速度又は減少速度を求める。次に、必要空気量に到達するまでの空気供給量の増加速度又は減少速度と、予め定められた適正空燃比とに基づいて、適正空燃比から外れずに燃料ガスの供給量が必要量に到達するように燃料ガスの供給量の増加速度又は減少速度を設定する。そして、設定した燃料ガスの供給量の増加速度又は減少速度に基づいて、空燃比制御手段32はソレノイド弁30を制御する。
The air-fuel ratio control means 32 detects the number of revolutions of the supercharger when the amount of supplied fuel gas fluctuates due to a change in the instruction of the governor, a load fluctuation, disturbance or the like, that is, when the amount of supplied fuel gas is changed. By controlling the duty ratio of the solenoid valve 30 based on the detection result of the means 31, the control of the amount of fuel gas supplied by the solenoid valve 30 can be freely performed, and the temporal change can be delayed.
That is, when the load on the gas engine 10 increases or decreases, the air supply amount and the gas fuel supply amount are controlled to increase or decrease in order to maintain the rotational speed of the gas engine 10. In the control, first, the actual air supply amount is calculated from the detected number of revolutions of the turbocharger 20, and the increase speed or decrease speed of the air supply amount until reaching the required air amount is determined. Next, based on the increase speed or decrease speed of the air supply amount until reaching the required air amount and the predetermined proper air-fuel ratio, the required amount of fuel gas supplied does not deviate from the proper air-fuel ratio The increase rate or decrease rate of the supplied amount of fuel gas is set so as to reach. Then, the air-fuel ratio control means 32 controls the solenoid valve 30 based on the set increase rate or decrease rate of the fuel gas supply amount.
負荷が変動した場合には、過給機20の応答が遅れるが、ソレノイド弁30は過給機20よりも応答が速いので、燃料ガスの供給量の設定が変更された場合は、空気の供給量よりも燃料ガスの供給量のほうが先に必要量に到達するため空燃比が変動して燃焼が不安定になってしまう。そこで、本実施形態のように、過給機20の回転数を検出し、その検出結果に基づいてソレノイド弁30による燃料ガスの供給量の時間的変化を遅くする(燃料ガスの供給量が必要量に到達するまでの増加速度又は減少速度を緩やかにする)ことで、空気の供給量の時間的変化に合わせ、空燃比が変動することを防止して一定にすることができる(図3参照)。したがって、ガスエンジン10における燃焼を安定させることができる。
なお、図3に示すように、ガスエンジン10の負荷が上昇した際に空燃比は一定であるが、ガスエンジン10の回転数は大きく低下している。しかし、負荷が発電機であって回転数低下による停電を防止するために回転数を一定に維持する必要がある場合等とは異なり、本実施形態のように負荷が船舶のプロペラ3である場合には、ガスエンジン10の回転数が低下しても一定の推進力を保つことができるため、回転数を一定に維持するよりも空燃比を一定に維持する制御を優先させることができる。
If the load fluctuates, the response of the supercharger 20 is delayed, but the response of the solenoid valve 30 is faster than the supercharger 20. Therefore, when the setting of the fuel gas supply amount is changed, the air is supplied. Since the amount of fuel gas supplied reaches the necessary amount earlier than the amount, the air-fuel ratio fluctuates and combustion becomes unstable. Therefore, as in the present embodiment, the rotational speed of the turbocharger 20 is detected, and based on the detection result, the temporal change in the amount of fuel gas supplied by the solenoid valve 30 is delayed (the amount of fuel gas supplied is required). By making the increase rate or decrease rate until the amount is reached), the air-fuel ratio can be prevented from fluctuating and made constant according to the temporal change of the air supply amount (see FIG. 3). ). Therefore, the combustion in the gas engine 10 can be stabilized.
As shown in FIG. 3, when the load of the gas engine 10 rises, the air-fuel ratio is constant, but the rotational speed of the gas engine 10 is greatly reduced. However, unlike the case where the load is a generator and it is necessary to keep the rotational speed constant to prevent a power failure due to a reduction in rotational speed, etc., the load is the propeller 3 of the ship as in this embodiment. In addition, since it is possible to maintain a constant propulsive force even if the rotational speed of the gas engine 10 decreases, control to maintain the air-fuel ratio constant can be prioritized over maintaining the rotational speed to be constant.
また、本実施形態のガスエンジンの空燃比制御装置は、ガスエンジン10のエンジン回転数を検出するエンジン回転数検出手段33を備えている。
空燃比制御手段32は、ガスエンジン10の回転数を考慮して実際のガス流量を算出し、そのガス流量を、燃料ガスの供給量が必要量に到達するまでの燃料ガスの供給量の増加速度又は減少速度の算出に用いる。燃料ガスの供給量が必要量に到達するまでの燃料ガスの供給量の増加速度又は減少速度を設定する際のパラメータとして実際のガス流量を用いることで、より正確に燃料ガスの供給量の時間的変化を制御することができる。
さらに、エンジン回転数検出手段33でガスエンジン10の回転数を検出できることを利用し、負荷が上昇したときに空燃比を保とうとしてガスエンジン10の回転数が下限を超える場合(ガスエンジン10が停止してしまうような場合)、又は負荷が減少したときにガスエンジン10の回転数が上限を超えて危険になる場合には、空燃比制御装置による空燃比制御を中止するように制御することができる。
Further, the air-fuel ratio control device for a gas engine of the present embodiment includes an engine rotational speed detection unit 33 that detects the engine rotational speed of the gas engine 10.
The air-fuel ratio control means 32 calculates the actual gas flow rate in consideration of the rotational speed of the gas engine 10, and increases the fuel gas supply amount until the fuel gas supply amount reaches the required amount. Used to calculate speed or decrease speed. By using the actual gas flow rate as a parameter in setting the increase rate or decrease rate of the fuel gas supply rate until the fuel gas supply rate reaches the required amount, the time of the fuel gas supply rate can be more accurately Change can be controlled.
Furthermore, by utilizing the fact that the engine speed detecting means 33 can detect the speed of the gas engine 10, and maintaining the air-fuel ratio when the load rises, the case where the speed of the gas engine 10 exceeds the lower limit (the gas engine 10 In the case where the engine is stopped) or when the rotational speed of the gas engine 10 becomes dangerous beyond the upper limit when the load decreases, the air-fuel ratio control by the air-fuel ratio control device is controlled to be discontinued. Can.
また、過給機20のコンプレッサー22とガスエンジン10の間の経路にはスロットル弁26を備えている。
スロットル弁26は、空燃比制御手段32の制御によって定常負荷時は絞った位置に臨ませている。そして、燃料ガスの供給量の設定が変更された場合は、空燃比制御手段32は、過給機回転数検出手段31による過給機20の回転数の検出結果が必要回転数より小さいつまり空気供給量が不足すると判断すると、スロットル弁26を開放して空気供給量を増加させる。定常負荷時にはスロットル弁26を絞って余力を持たせておき、負荷が上昇した際は応答の速いスロットル弁26を開放して空気供給量を速く増加させることで必要空気量に到達するまでの時間を短縮することができ、空燃比を一定に保ち易くなる。
In addition, a throttle valve 26 is provided in a path between the compressor 22 of the turbocharger 20 and the gas engine 10.
The throttle valve 26 is controlled by the air-fuel ratio control means 32 to reach a throttled position during steady load. When the setting of the supply amount of the fuel gas is changed, the air-fuel ratio control means 32 detects that the rotational speed of the supercharger 20 is detected by the supercharger rotational speed detection means 31 is smaller than the required rotational speed, that is, air. If it is determined that the supply amount is insufficient, the throttle valve 26 is opened to increase the air supply amount. At steady load, throttle valve 26 is squeezed to give remaining capacity, and when load increases, time to reach required air amount by opening fast response throttle valve 26 and rapidly increasing air supply amount Can be shortened, and the air-fuel ratio can be easily kept constant.
また、空燃比制御手段32は、燃料ガスの供給量の設定が変更された場合は、過給機回転数検出手段31による過給機20の回転数の検出結果に基づいて可変ノズル23を制御する。例えば過給機20の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、応答の速い可変ノズル23のノズル翼の向きや角度によって排気ガス通路を変化させてガスエンジン10から供給される排気ガスの流速を調整して加圧空気の加圧特性を改善し、空気供給量を速く増やすことができ、空燃比を一定に保ち易くなる。 Further, when the setting of the supply amount of the fuel gas is changed, the air-fuel ratio control means 32 controls the variable nozzle 23 based on the detection result of the rotational speed of the supercharger 20 by the supercharger rotational speed detection means 31. Do. For example, when the rotation speed of the supercharger 20 is lower than the required rotation speed, that is, when the air supply amount is insufficient, the exhaust gas passage is changed according to the direction and the angle of the nozzle blade of the variable nozzle 23 having quick response. Thus, it is possible to improve the pressurization characteristic of the pressurized air by adjusting the flow velocity of the exhaust gas supplied from the above, to rapidly increase the air supply amount, and to easily keep the air-fuel ratio constant.
また、ガスエンジン10とタービン21との間の排気ガス通路から分岐し、過給機20のタービン21を迂回してタービン21の下流側の排気ガス通路に合流するバイパス経路24と、バイパス経路24に設けられてバイパス経路24を開閉するバイパス制御弁25を備える。
空燃比制御手段32は、燃料ガスの供給量の設定が変更された場合は、過給機回転数検出手段31による過給機20の回転数の検出結果に基づいて、バイパス制御弁25の開閉制御を行う。すなわち、過給機20の回転数が必要回転数より低い場合つまり空気供給量が不足する場合には、予め開けてあるバイパス経路24の開度を応答の速いバイパス制御弁25で絞り、過給機20の回転数を増し空気供給量を速く増やすことができる。また、過給機20の回転数が必要回転数より大きい場合にはバイパス制御弁25を開いてバイパス経路24に排気ガスを流し、タービン21を迂回させることで過給機20の回転数を下げて空気供給量を速く減少させることができる。
このように、排気ガスは過給機20の回転数に応じてタービン21を迂回させることで、過給機20の回転数を調整することができ、空燃比を一定に保ち易くなる。
Further, a bypass passage 24 branched from the exhaust gas passage between the gas engine 10 and the turbine 21 and bypassing the turbine 21 of the turbocharger 20 and joining the exhaust gas passage on the downstream side of the turbine 21; And a bypass control valve 25 that opens and closes the bypass path 24.
When the setting of the supply amount of the fuel gas is changed, the air-fuel ratio control means 32 opens and closes the bypass control valve 25 based on the detection result of the rotational speed of the supercharger 20 by the supercharger rotational speed detection means 31. Take control. That is, when the number of revolutions of the supercharger 20 is lower than the necessary number of revolutions, that is, when the air supply amount is insufficient, the opening degree of the bypass path 24 opened in advance is throttled by the bypass control valve 25 having quick response. The number of rotations of the machine 20 can be increased to rapidly increase the air supply amount. Further, when the rotation speed of the turbocharger 20 is higher than the necessary rotation speed, the bypass control valve 25 is opened to flow the exhaust gas to the bypass path 24 to bypass the turbine 21 to reduce the rotation speed of the turbocharger 20 Thus, the air supply can be reduced rapidly.
As described above, by causing the exhaust gas to bypass the turbine 21 according to the rotational speed of the turbocharger 20, the rotational speed of the turbocharger 20 can be adjusted, and the air-fuel ratio can be easily maintained constant.
また、本実施形態において、プロペラ3は可変ピッチプロペラとしている。可変ピッチプロペラ3は、ガスエンジン10により駆動され、油圧やモータ等によりピッチが変更される。
空燃比制御手段32は、燃料ガスの供給量の設定が変更された場合は、過給機回転数検出手段31による過給機20の回転数の検出結果に基づいて、可変ピッチプロペラ3のピッチ制御を行う。すなわち、過給機20の回転数が必要回転数より小さい場合又は大きい場合には応答の速い可変ピッチプロペラ3のピッチを変えてガスエンジン10にかかる負荷を増減することで、空燃比を一定に保ち易くなる。
Further, in the present embodiment, the propeller 3 is a variable pitch propeller. The variable pitch propeller 3 is driven by the gas engine 10, and its pitch is changed by oil pressure, a motor or the like.
When the setting of the supply amount of the fuel gas is changed, the air-fuel ratio control means 32 determines the pitch of the variable pitch propeller 3 based on the detection result of the rotational speed of the supercharger 20 by the supercharger rotational speed detection means 31. Take control. That is, when the rotation speed of the supercharger 20 is smaller or larger than the necessary rotation speed, the air-fuel ratio is made constant by changing the pitch of the quick response variable pitch propeller 3 to increase or decrease the load applied to the gas engine 10 It becomes easy to keep.
なお、本実施形態において燃料供給量制御手段(ソレノイド弁)30は、燃料ガスの供給量を制御するものとして説明したが、予め燃料ガスと空気とを混合し、この空気を混合した燃料ガスの供給量を制御するものであってもよく、例えば予混合リーンバーン燃焼方式ガスエンジンにも適用することができる。また、燃料供給量制御手段30には、パイロット燃料を供給する型式のパイロット燃料弁や、追加燃料の供給を行う型式の複数の燃料供給弁等、およそ燃料供給に係わる手段は全て含むものとする。また、過給機回転数検出手段31の検出結果は、負荷変動時の制御以外にも、定常運転時の運転の監視や過給機20の管理に役立てることができる。また、過給機回転数は、過給機特性と加圧圧力等を用いて間接的に検出してもよい。 In the present embodiment, the fuel supply amount control means (solenoid valve) 30 has been described as controlling the supply amount of the fuel gas, but the fuel gas and air are mixed in advance, and the air is mixed. The supply amount may be controlled, and may be applied to, for example, a premixed lean-burn combustion gas engine. Further, the fuel supply amount control means 30 includes all means related to fuel supply such as a pilot fuel valve of a type for supplying a pilot fuel, and a plurality of fuel supply valves of a type for supplying an additional fuel. Further, the detection result of the supercharger rotational speed detection means 31 can be used for monitoring of operation during steady operation and management of the supercharger 20, in addition to control during load fluctuation. Further, the turbocharger rotational speed may be detected indirectly by using the turbocharger characteristic, the pressurizing pressure and the like.
図4及び図5を用いて、本発明の他の実施形態によるガスエンジンの空燃比制御装置について説明する。図4は本発明の他の実施形態によるガスエンジンの空燃比制御装置の概略構成図、図5は同空燃比制御装置のエンジン負荷変動に対する空燃比制御を示す図である。なお、上記した実施形態と同一機能部材には同一符号を付して説明を省略する。
本実施形態によるガスエンジンの空燃比制御装置は、可変ノズル23、バイパス経路24、バイパス制御弁25、スロットル弁26、及びエンジン回転数検出手段33を備えず、加勢手段であるモータ/ジェネレータ40を備える点において上記した実施形態と異なる。
An air-fuel ratio control apparatus for a gas engine according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic block diagram of an air-fuel ratio control system for a gas engine according to another embodiment of the present invention, and FIG. 5 is a view showing air-fuel ratio control for engine load fluctuation of the air-fuel ratio control system. The same functional members as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
The air-fuel ratio control apparatus for a gas engine according to the present embodiment does not include the variable nozzle 23, the bypass path 24, the bypass control valve 25, the throttle valve 26, and the engine speed detection means 33, and The present embodiment is different from the above-described embodiment in the provision point.
モータ/ジェネレータ40は、過給機20に接続されている。
空燃比制御手段32は、燃料ガスの供給量の設定が変更された場合は、過給機回転数検出手段31による過給機20の回転数の検出結果に基づいて、モータ/ジェネレータ40の制御を行う。すなわち、過給機20の回転数が必要回転数より小さい場合つまり空気供給量が不足する場合には、過給機20を加勢するモータとして使用して過給機20の回転数を上げて必要空気量を速く確保し、過給機20の回転数が必要回転数より大きい場合つまり空気供給量が過多の場合には、ジェネレータとして発電することで過給機20の回転を抑えて空気供給量を減らす。モータとしての加勢又はジェネレータとしての発電は電気的なものであるため、その動作は瞬時に行われる。したがって、過給機20の回転数の検出結果に基づいて、モータ/ジェネレータ40の制御を行った場合には、図5(a)に示すように、空燃比の変動を一定以下に抑え易くなると共に、エンジン回転数の落ち込みも比較的短時間に留めることができる。
さらに、本実施形態において空燃比制御手段32は、過給機回転数検出手段31の検出結果に基づいて、モータ/ジェネレータ40の制御に加えて、ソレノイド弁30による燃料ガスの供給量の時間的変化を遅くする制御を併せて行うため、図5(b)に示すように、空燃比を一定にすることができる。
なお、加勢手段40は、ジェネレータ機能を有さないモータであってもよく、また、空気圧縮機など空気圧や油圧を利用して過給機20を加勢するものであってもよい。
The motor / generator 40 is connected to the turbocharger 20.
When the setting of the supply amount of the fuel gas is changed, the air-fuel ratio control means 32 controls the motor / generator 40 based on the detection result of the rotational speed of the supercharger 20 by the supercharger rotational speed detection means 31. I do. That is, when the number of revolutions of the turbocharger 20 is smaller than the necessary number of revolutions, that is, when the air supply amount is insufficient, the number of revolutions of the turbocharger 20 needs to be increased by using the turbocharger 20 as a motor. If the amount of air is secured quickly and the number of revolutions of the turbocharger 20 is greater than the required number of revolutions, that is, if the amount of air supply is excessive, the rotation of the turbocharger 20 is suppressed by generating electricity as a generator to reduce the amount of air supplied. Reduce Since the motor activation or generator generation is electrical, its operation is instantaneous. Therefore, when control of the motor / generator 40 is performed based on the detection result of the rotational speed of the turbocharger 20, as shown in FIG. At the same time, the drop in engine speed can be kept relatively short.
Further, in the present embodiment, the air-fuel ratio control means 32 temporally supplies the amount of fuel gas supplied by the solenoid valve 30 in addition to the control of the motor / generator 40 based on the detection result of the supercharger rotational speed detection means 31. Since the control for delaying the change is also performed, as shown in FIG. 5B, the air-fuel ratio can be made constant.
The biasing means 40 may be a motor not having a generator function, or may be a compressor such as an air compressor which boosts the turbocharger 20 using air pressure or oil pressure.
以上、各実施形態で説明したように、本発明のガスエンジンの空燃比制御装置は、過給機20の回転数を検出し、その検出結果に基づいて燃料供給量制御手段30による燃料ガスの供給量の時間的変化を遅くすることで空気の供給量の時間的変化に合わせ、空燃比を一定にすることができる。したがって、ガスエンジン10における燃焼を安定させることができる。
また、その空燃比制御装置付きガスエンジン10を搭載した船舶を提供することができる。
As described above in each embodiment, the air-fuel ratio control device of the gas engine according to the present invention detects the number of revolutions of the turbocharger 20, and based on the detection result, the fuel gas control unit 30 By delaying the temporal change of the supply amount, it is possible to make the air-fuel ratio constant according to the temporal change of the air supply amount. Therefore, the combustion in the gas engine 10 can be stabilized.
Further, it is possible to provide a ship equipped with the gas engine 10 with the air-fuel ratio control device.
本発明のガスエンジンの空燃比制御装置は、過給機の回転数に基づいて燃料供給量制御手段による燃料ガスの供給量の時間的変化を遅くすることで、空燃比を一定に保つことができるため、船舶をはじめとした陸舶産業用の各種のガスエンジンに適用することができる。 The air-fuel ratio control device for a gas engine according to the present invention can keep the air-fuel ratio constant by delaying temporal change in the amount of supplied fuel gas by the fuel supply amount control means based on the number of revolutions of the turbocharger. As it can, it can be applied to various gas engines for land and marine industries including ships.
10 ガスエンジン
20 過給機
21 タービン
22 コンプレッサー
23 可変ノズル
24 バイパス経路
25 バイパス制御弁
26 スロットル弁
30 燃料供給量制御手段(ソレノイド弁)
31 過給機回転数検出手段
32 空燃比制御手段
33 エンジン回転数検出手段
40 加勢手段(モータ/ジェネレータ)
Reference Signs List 10 gas engine 20 supercharger 21 turbine 22 compressor 23 variable nozzle 24 bypass path 25 bypass control valve 26 throttle valve 30 fuel supply amount control means (solenoid valve)
31. Turbocharger rotational speed detection means 32. Air fuel ratio control means 33. Engine rotational speed detection means 40. Actuating means (motor / generator).
Claims (12)
前記空燃比制御手段は、前記燃料ガスの前記燃料供給量の設定変更がされた場合に前記過給機回転数検出手段の前記検出結果に基づいて前記スロットル弁を制御することを特徴とする請求項1から請求項4のうちの1項に記載のガスエンジンの空燃比制御装置。 A throttle valve is provided in a path between the compressor and the gas engine of the turbocharger.
The air-fuel ratio control means controls the throttle valve based on the detection result of the supercharger rotational speed detection means when the setting of the fuel supply amount of the fuel gas is changed. An air-fuel ratio control device for a gas engine according to any one of claims 1 to 4.
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