JP2024070601A - Control device for internal combustion engine - Google Patents

Control device for internal combustion engine Download PDF

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JP2024070601A
JP2024070601A JP2022181195A JP2022181195A JP2024070601A JP 2024070601 A JP2024070601 A JP 2024070601A JP 2022181195 A JP2022181195 A JP 2022181195A JP 2022181195 A JP2022181195 A JP 2022181195A JP 2024070601 A JP2024070601 A JP 2024070601A
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air
fuel ratio
internal combustion
combustion engine
cylinders
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匡彦 増渕
俊博 森
大 小林
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Toyota Motor Corp
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Abstract

【課題】排気ガス中の大気汚染物質を低減させる。【解決手段】複数の気筒♯１～♯４と、複数の気筒♯１～♯４から排出された排気ガスを浄化する三元触媒３２と、を備える内燃機関１を制御し、複数の気筒♯１～♯４にそれぞれ異なる空燃比を設定できる内燃機関の制御装置１０であって、複数の気筒♯１～♯４の気筒毎に空燃比を設定して、複数の気筒♯１～♯４が１回ずつ燃焼する１サイクルの中に理論空燃比より空燃比がリッチな気筒と理論空燃比より空燃比がリーンな気筒とを少なくとも１つずつ含むように制御する。【選択図】図２[Problem] To reduce air pollutants in exhaust gas. [Solution] An internal combustion engine control device 10 controls an internal combustion engine 1 equipped with multiple cylinders #1 to #4 and a three-way catalyst 32 that purifies exhaust gas discharged from the multiple cylinders #1 to #4, and can set different air-fuel ratios for each of the multiple cylinders #1 to #4, and controls the air-fuel ratio for each of the multiple cylinders #1 to #4 so that one cycle in which each of the multiple cylinders #1 to #4 combusts once includes at least one cylinder whose air-fuel ratio is richer than the theoretical air-fuel ratio and at least one cylinder whose air-fuel ratio is leaner than the theoretical air-fuel ratio. [Selected Figure] Figure 2

Description

本発明は、複数の気筒から排出された排気ガスを浄化する浄化触媒を備える内燃機関を制御対象とする内燃機関の制御装置に関する。 The present invention relates to a control device for an internal combustion engine that controls an internal combustion engine equipped with a purification catalyst that purifies exhaust gas discharged from multiple cylinders.

特許文献１には、浄化触媒の暖機要求があった際に、４つの気筒のうち１つの気筒を理論空燃比より空燃比がリッチな気筒として、残りの３つの気筒を理論空燃比より空燃比がリーンな気筒とするように燃料噴射弁を操作する制御を行うことによって、浄化触媒を昇温させる内燃機関の制御装置が開示されている。 Patent Document 1 discloses a control device for an internal combustion engine that, when there is a request to warm up the purification catalyst, controls the fuel injection valve so that one of the four cylinders has an air-fuel ratio richer than the theoretical air-fuel ratio, and the remaining three cylinders have an air-fuel ratio leaner than the theoretical air-fuel ratio, thereby raising the temperature of the purification catalyst.

特開２０２０－０７０７８７号公報JP 2020-070787 A

特許文献１に開示された内燃機関の制御装置では、リッチな空燃比に設定された気筒から排出された余剰燃料が浄化触媒に付着し、リーンな空燃比に設定された気筒から排出された排気ガスによるリーン雰囲気下で燃焼することによって、浄化触媒が昇温し、浄化触媒から被毒物質を離脱させることができる。この昇温処理は、浄化触媒の暖機要求があった際のみ実行され、実行される度に浄化触媒から被毒物質を離脱させて、触媒の浄化性能を回復させることができる。しかし、特許文献１に開示された発明は、昇温処理によって一時的に浄化触媒を昇温させて浄化性能を回復させるものであって、昇温処理を実行していない状態における排気ガス中の大気汚染物質を低減させる点については、更に改善の余地がある。 In the control device for an internal combustion engine disclosed in Patent Document 1, excess fuel discharged from a cylinder set to a rich air-fuel ratio adheres to a purification catalyst, and is burned in a lean atmosphere by exhaust gas discharged from a cylinder set to a lean air-fuel ratio, thereby raising the temperature of the purification catalyst and removing poisonous substances from the purification catalyst. This temperature raising process is executed only when there is a request to warm up the purification catalyst, and each time it is executed, poisonous substances are removed from the purification catalyst and the purification performance of the catalyst can be restored. However, the invention disclosed in Patent Document 1 temporarily raises the temperature of the purification catalyst by the temperature raising process to restore the purification performance, and there is room for further improvement in terms of reducing air pollutants in the exhaust gas when the temperature raising process is not being executed.

そこで、本発明は、排気ガス中の大気汚染物質を低減させることができる内燃機関の制御装置を提供することを目的とする。 The present invention aims to provide a control device for an internal combustion engine that can reduce air pollutants in exhaust gas.

本発明に係る内燃機関の制御装置は、複数の気筒と、前記複数の気筒から排出された排気ガスを浄化する浄化触媒と、を備える内燃機関を制御し、前記複数の気筒にそれぞれ異なる空燃比を設定できる内燃機関の制御装置であって、前記複数の気筒の気筒毎に空燃比を設定して、前記複数の気筒が１回ずつ燃焼する１サイクルの中に理論空燃比より空燃比がリッチな気筒と前記理論空燃比より空燃比がリーンな気筒とを少なくとも１つずつ含むように制御することを特徴とする。 The control device for an internal combustion engine according to the present invention is a control device for an internal combustion engine that controls an internal combustion engine having a plurality of cylinders and a purification catalyst that purifies exhaust gas discharged from the plurality of cylinders, and can set different air-fuel ratios for each of the plurality of cylinders, and is characterized in that the control device sets an air-fuel ratio for each of the plurality of cylinders, and controls the air-fuel ratio so that one cycle in which each of the plurality of cylinders combusts once includes at least one cylinder whose air-fuel ratio is richer than the theoretical air-fuel ratio and at least one cylinder whose air-fuel ratio is leaner than the theoretical air-fuel ratio.

本発明に係る内燃機関の制御装置の一態様において、前記複数の気筒が１回ずつ燃焼する１サイクルの中に、燃焼する順番に気筒毎の空燃比を増減させる周期が１回又は複数回含まれるように制御してもよい。 In one aspect of the control device for an internal combustion engine according to the present invention, one cycle in which each of the multiple cylinders combusts once may include one or more periods in which the air-fuel ratio of each cylinder is increased or decreased in the order in which the cylinders combust.

本発明は、排気ガス中の大気汚染物質を低減させることができる。 The present invention can reduce air pollutants in exhaust gases.

本開示の実施形態の内燃機関の制御装置の制御系統を示す図である。1 is a diagram showing a control system of an internal combustion engine control device according to an embodiment of the present disclosure. 本実施形態の内燃機関の制御装置における各気筒の空燃比の設定値の一例を示す図である。4 is a diagram showing an example of setting values of the air-fuel ratio of each cylinder in the control device for the internal combustion engine of the present embodiment. FIG. 三元触媒における吸蔵酸素量の変化を説明する図である。FIG. 4 is a diagram illustrating a change in the amount of oxygen stored in a three-way catalyst.

以下、図１～３を参照しながら、本実施形態の内燃機関の制御装置１０について説明する。図１は、内燃機関の制御装置１０の制御系統を示す図である。内燃機関の制御装置１０は、図１に示す内燃機関１を制御する。内燃機関１は、４つの気筒♯１～♯４が一方向に並べられた直列４気筒型の内燃機関として構成されている。内燃機関１では、気筒♯１、気筒♯３、気筒♯４、気筒♯２の順番に燃焼が行われる。内燃機関１は、この順番に４つの気筒♯１～♯４が１回ずつ燃焼する度にクランクシャフトが２回転する。内燃機関１は、４つの気筒♯１～♯４へそれぞれ燃料を供給する４つのインジェクタ１１を備える。 The internal combustion engine control device 10 of this embodiment will be described below with reference to Figures 1 to 3. Figure 1 is a diagram showing a control system of the internal combustion engine control device 10. The internal combustion engine control device 10 controls the internal combustion engine 1 shown in Figure 1. The internal combustion engine 1 is configured as an in-line four-cylinder internal combustion engine in which four cylinders #1 to #4 are arranged in one direction. In the internal combustion engine 1, combustion occurs in the order of cylinder #1, cylinder #3, cylinder #4, and cylinder #2. In the internal combustion engine 1, the crankshaft rotates two times each time the four cylinders #1 to #4 combust once in this order. The internal combustion engine 1 has four injectors 11 that supply fuel to each of the four cylinders #1 to #4.

４つの気筒♯１～♯４は、吸気マニホールド２１を介して吸気通路２に接続し、排気マニホールド３１を介して排気通路３に接続している。そのため、吸気通路２を流れる吸入空気は吸気マニホールド２１で４つの気筒♯１～♯４へ分流され、４つの気筒♯１～４から排出される排気ガスは、排気マニホールド３１で合流されて排気通路３へ流入し、後述する三元触媒３２で浄化されてから大気へ放出される。 The four cylinders #1 to #4 are connected to the intake passage 2 via the intake manifold 21, and to the exhaust passage 3 via the exhaust manifold 31. Therefore, the intake air flowing through the intake passage 2 is divided into the four cylinders #1 to #4 by the intake manifold 21, and the exhaust gas discharged from the four cylinders #1 to #4 is merged in the exhaust manifold 31 and flows into the exhaust passage 3, where it is purified by the three-way catalyst 32 described below before being released into the atmosphere.

吸気通路２には、吸気通路２を流れる吸入空気の流量を検出するエアフローメータ２２と、吸入空気の流量を調整するスロットル弁２３と、スロットル弁２３の開度を検出するスロットル弁開度センサ２４が設けられている。 The intake passage 2 is provided with an air flow meter 22 that detects the flow rate of intake air flowing through the intake passage 2, a throttle valve 23 that adjusts the flow rate of intake air, and a throttle valve opening sensor 24 that detects the opening degree of the throttle valve 23.

内燃機関１は、排気通路３に設けられた三元触媒３２を備える。三元触媒３２は、４つの気筒♯１～♯４から排出された排気ガスを浄化する浄化触媒である。三元触媒３２は、酸素吸蔵能力を有し、排気ガス中の炭化水素を水と二酸化炭素に酸化し、一酸化炭素を二酸化炭素に酸化し、窒素酸化物を窒素に還元する。そのため、三元触媒３２は排気ガス中の炭化水素、一酸化炭素及び窒素酸化物等の大気汚染物質を無害な物質に化学変化させることによって、排気ガスを浄化することができる。 The internal combustion engine 1 is equipped with a three-way catalyst 32 provided in the exhaust passage 3. The three-way catalyst 32 is a purification catalyst that purifies the exhaust gas discharged from the four cylinders #1 to #4. The three-way catalyst 32 has oxygen storage capacity, and oxidizes the hydrocarbons in the exhaust gas to water and carbon dioxide, oxidizes the carbon monoxide to carbon dioxide, and reduces the nitrogen oxides to nitrogen. Therefore, the three-way catalyst 32 can purify the exhaust gas by chemically changing air pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides in the exhaust gas into harmless substances.

排気通路３の三元触媒３２より上流側には、Ａ／Ｆセンサ３３が設けられており、三元触媒３２より上流側の排気の酸素濃度を検出することができる。Ａ／Ｆセンサ３３で検出する酸素濃度は内燃機関１の空燃比に対応するため、Ａ／Ｆセンサ３３は内燃機関１の空燃比のモニターの用途に用いることができる。 An A/F sensor 33 is provided upstream of the three-way catalyst 32 in the exhaust passage 3, and is capable of detecting the oxygen concentration in the exhaust upstream of the three-way catalyst 32. Since the oxygen concentration detected by the A/F sensor 33 corresponds to the air-fuel ratio of the internal combustion engine 1, the A/F sensor 33 can be used to monitor the air-fuel ratio of the internal combustion engine 1.

内燃機関の制御装置１０は、ＥＣＵ（Ｅｌｅｃｔｒｏｎｉｃ Ｃｏｎｔｒｏｌ Ｕｎｉｔ）４を備える。ＥＣＵ４には、内燃機関１のクランク角センサ１２、アクセル開度センサ５、エアフローメータ２２、スロットル弁開度センサ２４及びＡ／Ｆセンサ３３から出力信号が入力される。そして、スロットル弁２３及びインジェクタ１１はＥＣＵ４によって制御される。ＥＣＵ４は、４つのインジェクタ１１にそれぞれ異なる燃料噴射量を設定できる。そのため、ＥＣＵ４は、４つの気筒♯１～♯４にそれぞれ設けられた不図示の吸気バルブのリフト量が全て同一であっても、４つのインジェクタ１１にそれぞれ異なる燃料噴射量を設定することによって、４つの気筒♯１～♯４にそれぞれ異なる空燃比を設定することができる。 The control device 10 of the internal combustion engine includes an ECU (Electronic Control Unit) 4. The ECU 4 receives output signals from the crank angle sensor 12, the accelerator opening sensor 5, the air flow meter 22, the throttle valve opening sensor 24, and the A/F sensor 33 of the internal combustion engine 1. The throttle valve 23 and the injector 11 are controlled by the ECU 4. The ECU 4 can set different fuel injection amounts for each of the four injectors 11. Therefore, even if the lift amounts of the intake valves (not shown) provided in each of the four cylinders #1 to #4 are all the same, the ECU 4 can set different air-fuel ratios for each of the four cylinders #1 to #4 by setting different fuel injection amounts for each of the four injectors 11.

ＥＣＵ４は、アクセル開度センサ５により検出されたアクセル開度に基づいてスロットル弁２３の開度を制御する。そして、ＥＣＵ４は、Ａ／Ｆセンサ３３の検出値から内燃機関１の空燃比を算出して、４つの気筒♯１～♯４の空燃比の平均値が理論空燃比へ近づくようにインジェクタ１１の燃料噴射量を調整するフィードバック制御を行う。このフィードバック制御では、ＥＣＵ４は、４つの気筒♯１～♯４のうち一部の気筒が理論空燃比よりリッチな空燃比となって、その他の気筒が理論空燃比よりリーンな空燃比となるように４つのインジェクタ１１の燃料噴射量を制御する。図２は、４つの気筒♯１～♯４の空燃比の設定値の一例を示す図である。図２に示す実施例では、ＥＣＵ４は、気筒♯１及び気筒♯２の空燃比が理論空燃比よりリーンとなって、気筒♯３及び気筒♯４の空燃比が理論空燃比よりリッチとなるように４つのインジェクタ１１の燃料噴射量を制御している。なお、吸気マニホールド２１の形状などの影響により、４つのインジェクタ１１の燃料噴射量を同一の値に設定した場合でも、４つの気筒♯１～♯４の空燃比にばらつきが生じることもあり得る。内燃機関の制御装置１０では、４つの気筒♯１～♯４の空燃比のばらつきの範囲が、４つのインジェクタ１１の燃料噴射量を同一の値に設定した場合に生じる気筒間の空燃比のばらつきの範囲よりも大きくなるように、ＥＣＵ４が４つのインジェクタ１１の燃料噴射量を制御する。 The ECU 4 controls the opening of the throttle valve 23 based on the accelerator opening detected by the accelerator opening sensor 5. The ECU 4 then calculates the air-fuel ratio of the internal combustion engine 1 from the detection value of the A/F sensor 33, and performs feedback control to adjust the fuel injection amount of the injector 11 so that the average value of the air-fuel ratio of the four cylinders #1 to #4 approaches the theoretical air-fuel ratio. In this feedback control, the ECU 4 controls the fuel injection amount of the four injectors 11 so that some of the four cylinders #1 to #4 have an air-fuel ratio richer than the theoretical air-fuel ratio, and the other cylinders have an air-fuel ratio leaner than the theoretical air-fuel ratio. Figure 2 is a diagram showing an example of the set values of the air-fuel ratios of the four cylinders #1 to #4. In the embodiment shown in FIG. 2, the ECU 4 controls the fuel injection amount of the four injectors 11 so that the air-fuel ratio of cylinders #1 and #2 is leaner than the theoretical air-fuel ratio, and the air-fuel ratio of cylinders #3 and #4 is richer than the theoretical air-fuel ratio. Note that even if the fuel injection amount of the four injectors 11 is set to the same value, the air-fuel ratio of the four cylinders #1 to #4 may vary due to the influence of the shape of the intake manifold 21, etc. In the control device 10 of the internal combustion engine, the ECU 4 controls the fuel injection amount of the four injectors 11 so that the range of variation in the air-fuel ratio of the four cylinders #1 to #4 is larger than the range of variation in the air-fuel ratio between the cylinders that occurs when the fuel injection amount of the four injectors 11 is set to the same value.

内燃機関１では、気筒♯１、気筒♯３、気筒♯４、気筒♯２の順番に燃焼が行われるため、図２に示すように空燃比を設定すると、気筒♯３及び気筒♯４から酸素濃度が低い排気ガスが排出された後に気筒♯２及び気筒♯１から酸素濃度が高い排気ガスが排出される現象が繰り返される。つまり、内燃機関１から排出される排気ガスの酸素濃度は、４つの気筒♯１～♯４が１回ずつ燃焼する１サイクル毎に増減することになる。そして、ＥＣＵ４は、少なくとも２サイクル以上、４つの気筒♯１～♯４の空燃比の設定値を維持する。 In the internal combustion engine 1, combustion takes place in the order of cylinder #1, cylinder #3, cylinder #4, and cylinder #2. Therefore, when the air-fuel ratio is set as shown in FIG. 2, the phenomenon in which exhaust gas with a low oxygen concentration is discharged from cylinder #3 and cylinder #4, and then exhaust gas with a high oxygen concentration is discharged from cylinder #2 and cylinder #1 is repeated. In other words, the oxygen concentration of the exhaust gas discharged from the internal combustion engine 1 increases or decreases with each cycle in which each of the four cylinders #1 to #4 burns once. The ECU 4 then maintains the set values of the air-fuel ratios of the four cylinders #1 to #4 for at least two cycles.

三元触媒３２では、空燃比がリーンの条件では酸化セリウムや貴金属に酸素が吸蔵され、空燃比がリッチな条件では酸化セリウムや貴金属から酸素が放出される。そのため、三元触媒３２は、図３に示すように、内燃機関１の空燃比がリーンな状態では吸蔵酸素量を増加させ、内燃機関１の空燃比がリッチな状態では吸蔵酸素量を減少させる。そして、空燃比をリッチな状態からリーンな状態に切り換えた直後は三元触媒３２の吸蔵酸素量が急上昇するものの、更にリーンな状態を継続すると吸蔵酸素量の上限に近づいて上昇速度が低下する。このような三元触媒３２の吸蔵酸素量の上限付近では、排気ガス中の窒素酸化物を還元させる能力が低下する。また、空燃比をリーンな状態からリッチな状態に切り換えた直後は三元触媒３２の吸蔵酸素量が急下降するものの、更にリッチな状態を継続すると吸蔵酸素量の下限に近づいて下降速度が低下する。このような三元触媒３２の吸蔵酸素量の下限付近では、排気ガス中の炭化水素と一酸化炭素を酸化させる能力が低下する。そのため、排気ガス中の大気汚染物質を低減させる効果が得られるメカニズムの１つとして、内燃機関１の空燃比を短い周期で理論空燃比よりリーンな状態とリッチな状態とを交互に繰り返すように切り替えることにより、三元触媒３２の吸蔵酸素量が上限付近又は下限付近に留まっている期間が短くなり、図３に破線で囲む吸放出速度が速い部分を頻繁に用いることが可能となり、排気ガス中の窒素酸化物を還元する能力が低下する期間や炭化水素及び一酸化炭素を酸化する能力が低下する期間を短くすることができる。 In the three-way catalyst 32, oxygen is stored in cerium oxide or precious metals when the air-fuel ratio is lean, and oxygen is released from cerium oxide or precious metals when the air-fuel ratio is rich. Therefore, as shown in FIG. 3, the three-way catalyst 32 increases the amount of stored oxygen when the air-fuel ratio of the internal combustion engine 1 is lean, and decreases the amount of stored oxygen when the air-fuel ratio of the internal combustion engine 1 is rich. Then, immediately after switching the air-fuel ratio from a rich state to a lean state, the amount of stored oxygen in the three-way catalyst 32 rises sharply, but if the lean state is continued, the amount of stored oxygen approaches the upper limit and the rate of increase decreases. Near the upper limit of the amount of stored oxygen in such a three-way catalyst 32, the ability to reduce nitrogen oxides in the exhaust gas decreases. Also, immediately after switching the air-fuel ratio from a lean state to a rich state, the amount of stored oxygen in the three-way catalyst 32 falls sharply, but if the rich state is continued, the rate of decrease decreases as the amount of stored oxygen approaches the lower limit. When the amount of oxygen stored in the three-way catalyst 32 is near the lower limit, the ability to oxidize the hydrocarbons and carbon monoxide in the exhaust gas decreases. Therefore, one mechanism for reducing the air pollutants in the exhaust gas is to alternate between a leaner and richer state than the theoretical air-fuel ratio in a short period of time. This shortens the period during which the amount of oxygen stored in the three-way catalyst 32 remains near the upper or lower limit, and the area with a high absorption and release speed, surrounded by the dashed line in Figure 3, can be used frequently, shortening the period during which the ability to reduce nitrogen oxides in the exhaust gas decreases and the ability to oxidize hydrocarbons and carbon monoxide decreases.

本実施形態の内燃機関の制御装置１０では、４つの気筒♯１～♯４が１回ずつ燃焼する１サイクル毎の短い周期で空燃比を理論空燃比よりリーンな状態とリッチな状態とを交互に繰り返すように増減させるため、上記のメカニズムにより、排気ガス中の窒素酸化物を還元する能力が低下する期間や炭化水素及び一酸化炭素を酸化する能力が低下する期間を短くすることができる。そのため、内燃機関の制御装置１０は、排気ガス中の窒素酸化物、炭化水素及び一酸化炭素等の大気汚染物質が低減させた状態で内燃機関１の使用を継続することができる。 In the internal combustion engine control device 10 of this embodiment, the air-fuel ratio is increased and decreased alternately between leaner and richer than the theoretical air-fuel ratio in a short period of one cycle in which each of the four cylinders #1 to #4 burns once, so that the above mechanism can shorten the period during which the ability to reduce nitrogen oxides in the exhaust gas decreases and the ability to oxidize hydrocarbons and carbon monoxide decreases. Therefore, the internal combustion engine control device 10 can continue to use the internal combustion engine 1 in a state in which air pollutants such as nitrogen oxides, hydrocarbons, and carbon monoxide in the exhaust gas are reduced.

排気ガス中の大気汚染物質の低減効果を検証するため、内燃機関１の回転速度と単位時間当たりの吸入空気量を同一の条件として、４つの気筒♯１～♯４のインジェクタ１１の燃料噴射量を同一の値に設定した場合と、４つの気筒♯１～♯４を図２に示す空燃比に設定されるようにインジェクタ１１の燃料噴射量を制御した場合について、排気ガス中の窒素酸化物と炭化水素の質量の合計値を実測した。その結果、４つの気筒♯１～♯４を図２に示す空燃比に設定されるようにインジェクタ１１の燃料噴射量を制御した場合は、４つの気筒♯１～♯４のインジェクタ１１の燃料噴射量を同一の値に設定した場合と比較して、排気ガス中の窒素酸化物と炭化水素の質量の合計値を基礎評価において最大で４０パーセント以上低減できることが判明した。 To verify the effect of reducing air pollutants in exhaust gas, the total mass of nitrogen oxides and hydrocarbons in exhaust gas was measured in the case where the fuel injection amount of the injectors 11 for the four cylinders #1 to #4 was set to the same value under the same conditions of the rotation speed of the internal combustion engine 1 and the intake air amount per unit time, and in the case where the fuel injection amount of the injectors 11 was controlled so that the air-fuel ratio of the four cylinders #1 to #4 was set as shown in Figure 2. As a result, it was found that the total mass of nitrogen oxides and hydrocarbons in exhaust gas can be reduced by up to 40% or more in the basic evaluation when the fuel injection amount of the injectors 11 for the four cylinders #1 to #4 was controlled so that the air-fuel ratio of the four cylinders #1 to #4 was set as shown in Figure 2, compared to the case where the fuel injection amount of the injectors 11 for the four cylinders #1 to #4 was set to the same value.

なお、図２に示す４つの気筒♯１～♯４の空燃比は設定値の一例であって、図２に示す設定値とは異なる空燃比となるように４つのインジェクタ１１の燃料噴射量を制御してもよい。例えば、気筒♯１及び気筒♯３の空燃比が理論空燃比よりリッチとなって、気筒♯４及び気筒♯２の空燃比が理論空燃比よりリーンとなるように４つのインジェクタ１１の燃料噴射量を制御してもよい。このような条件で内燃機関１を使用した場合でも、４つの気筒♯１～♯４のインジェクタ１１の燃料噴射量を同一の値に設定した場合と比較して、排気ガス中の窒素酸化物と炭化水素の質量の合計値を基礎評価において最大で４０パーセント低減できることが判明している。また、内燃機関１の回転速度が遅い条件では、例えば、気筒♯１及び気筒♯４の空燃比が理論空燃比よりリーンとなって、気筒♯３及び気筒♯２の空燃比が理論空燃比よりリッチとなるように４つのインジェクタ１１の燃料噴射量を制御してもよい。この場合、４つの気筒♯１～♯４が１回ずつ燃焼する１サイクル毎に空燃比を２回増減させることになる。 Note that the air-fuel ratios of the four cylinders #1 to #4 shown in FIG. 2 are examples of set values, and the fuel injection amounts of the four injectors 11 may be controlled to achieve air-fuel ratios different from the set values shown in FIG. 2. For example, the fuel injection amounts of the four injectors 11 may be controlled so that the air-fuel ratios of the cylinders #1 and #3 are richer than the theoretical air-fuel ratio, and the air-fuel ratios of the cylinders #4 and #2 are leaner than the theoretical air-fuel ratio. Even when the internal combustion engine 1 is used under such conditions, it has been found that the total mass of nitrogen oxides and hydrocarbons in the exhaust gas can be reduced by up to 40% in a basic evaluation, compared to when the fuel injection amounts of the injectors 11 of the four cylinders #1 to #4 are set to the same value. In addition, under conditions where the rotation speed of the internal combustion engine 1 is slow, for example, the fuel injection amounts of the four injectors 11 may be controlled so that the air-fuel ratios of the cylinders #1 and #4 are leaner than the theoretical air-fuel ratio, and the air-fuel ratios of the cylinders #3 and #2 are richer than the theoretical air-fuel ratio. In this case, the air-fuel ratio will be increased or decreased twice for each cycle in which each of the four cylinders #1 to #4 burns once.

＜実施形態の補足＞
本開示の内燃機関の制御装置は、上述した形態に限定されず、本開示の要旨の範囲内において種々の形態にて実施できる。例えば、制御の対象となる内燃機関は、直列３気筒エンジンやＶ型６気筒エンジンやＶ型８気筒エンジンなど、直列４気筒型以外の内燃機関であってもよい。 <Supplementary description of embodiment>
The internal combustion engine control device of the present disclosure is not limited to the above-described embodiment, and may be embodied in various forms within the scope of the gist of the present disclosure. For example, the internal combustion engine to be controlled may be an internal combustion engine other than an inline 4-cylinder engine, such as an inline 3-cylinder engine, a V6 engine, or a V8 engine.

１ 内燃機関、２ 吸気通路、３ 排気通路、４ ＥＣＵ、５ アクセル開度センサ、１０ 内燃機関の制御装置、１１ インジェクタ、１２ クランク角センサ、２１ 吸気マニホールド、２２ エアフローメータ、２３ スロットル弁、２４ スロットル弁開度センサ、３１ 排気マニホールド、３２ 三元触媒、３３ Ａ／Ｆセンサ、♯１，♯２，♯３，♯４ 気筒。 1 internal combustion engine, 2 intake passage, 3 exhaust passage, 4 ECU, 5 accelerator opening sensor, 10 internal combustion engine control device, 11 injector, 12 crank angle sensor, 21 intake manifold, 22 air flow meter, 23 throttle valve, 24 throttle valve opening sensor, 31 exhaust manifold, 32 three-way catalyst, 33 A/F sensor, #1, #2, #3, #4 cylinders.

Claims (2)

複数の気筒と、前記複数の気筒から排出された排気ガスを浄化する浄化触媒と、を備える内燃機関を制御し、前記複数の気筒にそれぞれ異なる空燃比を設定できる内燃機関の制御装置であって、
前記複数の気筒の気筒毎に空燃比を設定して、前記複数の気筒が１回ずつ燃焼する１サイクルの中に理論空燃比より空燃比がリッチな気筒と前記理論空燃比より空燃比がリーンな気筒とを少なくとも１つずつ含むように制御することを特徴とする内燃機関の制御装置。 A control device for an internal combustion engine that controls an internal combustion engine having a plurality of cylinders and a purification catalyst that purifies exhaust gas discharged from the plurality of cylinders, and that can set different air-fuel ratios for the plurality of cylinders,
a control device for an internal combustion engine, the control device setting an air-fuel ratio for each of the plurality of cylinders, and controlling the air-fuel ratio so that one cycle in which each of the plurality of cylinders combusts once includes at least one cylinder whose air-fuel ratio is richer than the stoichiometric air-fuel ratio and at least one cylinder whose air-fuel ratio is leaner than the stoichiometric air-fuel ratio. 請求項１に記載の内燃機関の制御装置であって、
前記複数の気筒が１回ずつ燃焼する１サイクルの中に、燃焼する順番に気筒毎の空燃比を増減させる周期が１回又は複数回含まれるように制御することを特徴とする内燃機関の制御装置。 The control device for an internal combustion engine according to claim 1,
A control device for an internal combustion engine, characterized in that one cycle in which each of the plurality of cylinders combusts once includes one or more periods in which the air-fuel ratio of each cylinder is increased or decreased in accordance with the order of combustion.
JP2022181195A 2022-11-11 2022-11-11 Control device for internal combustion engine Pending JP2024070601A (en)

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