JP2022090200A - diesel engine - Google Patents
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- JP2022090200A JP2022090200A JP2020202430A JP2020202430A JP2022090200A JP 2022090200 A JP2022090200 A JP 2022090200A JP 2020202430 A JP2020202430 A JP 2020202430A JP 2020202430 A JP2020202430 A JP 2020202430A JP 2022090200 A JP2022090200 A JP 2022090200A
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- 238000002347 injection Methods 0.000 claims abstract description 181
- 239000007924 injection Substances 0.000 claims abstract description 181
- 239000000446 fuel Substances 0.000 claims abstract description 98
- 230000008929 regeneration Effects 0.000 claims abstract description 53
- 238000011069 regeneration method Methods 0.000 claims abstract description 53
- 238000002485 combustion reaction Methods 0.000 claims abstract description 32
- 230000009467 reduction Effects 0.000 claims abstract description 20
- 239000003054 catalyst Substances 0.000 claims abstract description 9
- 238000011144 upstream manufacturing Methods 0.000 claims description 120
- 230000003197 catalytic effect Effects 0.000 claims description 74
- UCQFCFPECQILOL-UHFFFAOYSA-N diethyl hydrogen phosphate Chemical compound CCOP(O)(=O)OCC UCQFCFPECQILOL-UHFFFAOYSA-N 0.000 claims description 66
- 238000000034 method Methods 0.000 claims description 66
- 230000008569 process Effects 0.000 claims description 63
- 238000011084 recovery Methods 0.000 claims description 52
- 238000009825 accumulation Methods 0.000 claims description 12
- 238000007254 oxidation reaction Methods 0.000 claims description 7
- 238000007084 catalytic combustion reaction Methods 0.000 claims description 6
- 230000010354 integration Effects 0.000 claims description 5
- 230000003647 oxidation Effects 0.000 claims description 5
- 230000001172 regenerating effect Effects 0.000 abstract description 3
- 239000000243 solution Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 28
- 230000007423 decrease Effects 0.000 description 11
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000000779 smoke Substances 0.000 description 6
- 239000003921 oil Substances 0.000 description 5
- 238000010790 dilution Methods 0.000 description 4
- 239000012895 dilution Substances 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000010705 motor oil Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
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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
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
- Exhaust Gas After Treatment (AREA)
- Processes For Solid Components From Exhaust (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
本発明は、ディーゼルエンジンに関し、詳しくは、無負荷及び/又は軽負荷運転時でも、DPFを再生できるディーゼルエンジンに関する。 The present invention relates to a diesel engine, and more particularly to a diesel engine capable of regenerating a DPF even during no-load and / or light-load operation.
従来、ディーゼルエンジンとして、PMの堆積でDPFの再生開始条件が成立した場合には、DOCの活性化後、ポスト噴射制御が開始され、DOCでのポスト噴射燃料の触媒燃焼で、排気がDPF再生温度まで昇温し、DPFに堆積したPMが焼却されるものがある(例えば、特許文献1参照)。 Conventionally, as a diesel engine, when the DPF regeneration start condition is satisfied by the accumulation of PM, the post-injection control is started after the activation of the DOC, and the exhaust gas is regenerated by the catalytic combustion of the post-injection fuel in the DOC. In some cases, the temperature is raised to a temperature and the PM deposited on the DPF is incinerated (see, for example, Patent Document 1).
《問題点》 無負荷及び軽負荷運転時には、DPFを再生できないおそれがある。
上記従来のエンジンでは、DPF再生開始時に、吸気絞り弁の開度を絞るが、これのみでは排気の昇温効率が低く、排気温度が低い無負荷及び軽負荷運転時には、DOCが活性化せず、ポスト噴射を行うことができず、DPFを再生できないおそれがある。
<< Problem >> The DPF may not be regenerated during no-load and light-load operation.
In the above-mentioned conventional engine, the opening of the intake throttle valve is narrowed at the start of DPF regeneration, but the efficiency of raising the exhaust gas is low by this alone, and the DOC is not activated during no-load and light-load operation where the exhaust temperature is low. , Post injection cannot be performed, and there is a possibility that the DPF cannot be regenerated.
本発明の課題は、無負荷及び/又は軽負荷運転時でも、DPFを再生できるディーゼルエンジンを提供することにある。 An object of the present invention is to provide a diesel engine capable of regenerating a DPF even during no-load and / or light-load operation.
本願発明の構成は、次の通りである。
図1に例示するように、燃焼室(1)に燃料(2)を噴射する燃料噴射装置(3)と、燃焼室(1)の排気下流側の排気管(4)内に燃料(2)を噴射する排気管インジェクタ(3a)と、排気管(4)内に配置された排気絞り弁(5)と、その排気下流側に配置された弁下流側DOC(6)と、その排気下流側に配置されたDPF(7)と、排気絞り弁(5)の開度と燃料噴射装置(3)及び排気管インジェクタ(3a)の燃料噴射を制御する電子制御装置(8)を備え、
図2に例示するように、DPF(7)の再生処理がなされるように構成され、
DPF(7)の再生処理では、PMが堆積したDPF(7)の再生処理の開始条件(S1)が成立した後に排気絞り弁(5)の開度減少制御(S2)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後に燃料噴射装置(3)のアフター噴射制御が開始(S5)され、アフター噴射燃料の燃焼で排気(9)が所定の排気管噴射許可温度(TP)以上の温度になった後に排気管噴射制御が開始(S7)され、図1に例示する排気管インジェクタ(3a)から排気管(4)内に噴射された排気管噴射燃料の弁下流側DOC(6)での触媒燃焼で昇温した排気(9)で、DPF(7)に堆積したPMが焼却されるように構成されている。
The configuration of the present invention is as follows.
As illustrated in FIG. 1, the fuel injection device (3) that injects the fuel (2) into the combustion chamber (1) and the fuel (2) in the exhaust pipe (4) on the exhaust downstream side of the combustion chamber (1). The exhaust pipe injector (3a) for injecting fuel, the exhaust throttle valve (5) arranged in the exhaust pipe (4), the valve downstream side DOC (6) arranged on the exhaust downstream side thereof, and the exhaust downstream side thereof. The DPF (7) arranged in the above, the opening degree of the exhaust throttle valve (5), the fuel injection device (3), and the electronic control device (8) for controlling the fuel injection of the exhaust pipe injector (3a) are provided.
As illustrated in FIG. 2, the DPF (7) is configured to be regenerated.
In the regeneration process of the DPF (7), the opening degree reduction control (S2) of the exhaust throttle valve (5) is performed after the start condition (S1) of the regeneration process of the DPF (7) in which PM is deposited is satisfied, and the exhaust gas (9) is exhausted (9). ) Is at a temperature equal to or higher than the predetermined after-injection permitted temperature (TA), the after-injection control of the fuel injection device (3) is started (S5), and the exhaust (9) is exhausted by the combustion of the after-injection fuel. Exhaust pipe injection control is started (S7) after the temperature reaches the injection permitted temperature (TP) or higher, and the exhaust pipe injection fuel injected from the exhaust pipe injector (3a) illustrated in FIG. 1 into the exhaust pipe (4). The PM deposited in the DPF (7) is incinerated by the exhaust gas (9) whose temperature has been raised by the catalytic combustion in the DOC (6) on the downstream side of the valve.
本願発明は、次の効果を奏する。
《効果1》無負荷及び/又は軽負荷運転時でも、DPF(7)を再生できる。
このエンジンでは、図2に例示するように、DPF(7)の再生処理の開始条件(S1)が成立した場合には、排気絞り弁(5)の開度減少による背圧の上昇、及びアフター噴射燃料の燃焼が起こるため、吸気絞りの場合に比べ、排気(9)の昇温効率が高く、排気温度が低い無負荷及び/又は軽負荷運転時でも、図1に例示する弁下流側DOC(6)が活性化され、排気管噴射で、DPF(7)を再生できる。
The invention of the present application has the following effects.
<<
In this engine, as illustrated in FIG. 2, when the start condition (S1) of the regeneration process of the DPF (7) is satisfied, the back pressure increases due to the decrease in the opening degree of the exhaust throttle valve (5), and after-sales. Since the combustion of the injected fuel occurs, the temperature rise efficiency of the exhaust (9) is higher and the exhaust temperature is lower than in the case of the intake throttle, even during no-load and / or light-load operation, the valve downstream side DOC exemplified in FIG. (6) is activated, and the DPF (7) can be regenerated by the exhaust pipe injection.
《効果2》エンジン出力を高くできる。
このエンジンでは、アフター噴射燃料の燃焼で排気(9)が昇温するため、図1に例示する排気絞り弁(5)の開度減少の度合いが小さくて済み、背圧による出力ロスが小さく、エンジン出力を高くできる。
<<
In this engine, since the exhaust (9) rises due to the combustion of the after-injection fuel, the degree of decrease in the opening degree of the exhaust throttle valve (5) illustrated in FIG. 1 is small, and the output loss due to back pressure is small. The engine output can be increased.
《効果3》DPF(7)再生時に弁下流側DOC(6)の低下した触媒機能を回復できる。
このエンジンでは、排気温度が低い無負荷及び/又は軽負荷運転の継続で、弁下流側DOC(6)に未燃焼燃料やPMからなる未燃焼堆積物が堆積し、その触媒機能が低下している場合でも、図2に例示するように、DPF(7)の再生処理の開始条件(S1)が成立した場合には、排気絞り弁(5)の開度減少やアフター噴射で、排気(9)が昇温し、未燃焼堆積物が気化或いは燃焼され、DPF(7)の再生時に図1に例示する弁下流側DOC(6)の低下した触媒機能を回復できる。また、白煙の原因である未燃焼堆積物がないため、白煙発生も抑えられる。
<<
In this engine, unburned deposits consisting of unburned fuel and PM are deposited on the DOC (6) on the downstream side of the valve due to the continuation of no-load and / or light-load operation with a low exhaust temperature, and its catalytic function deteriorates. Even if the exhaust gas is present, as illustrated in FIG. 2, when the start condition (S1) of the regeneration process of the DPF (7) is satisfied, the opening of the exhaust throttle valve (5) is reduced or the after injection is performed to exhaust the exhaust gas (9). ) Raises the temperature, the unburned deposit is vaporized or burned, and the reduced catalytic function of the valve downstream DOC (6) exemplified in FIG. 1 can be restored during the regeneration of the DPF (7). In addition, since there is no unburned deposit that causes white smoke, the generation of white smoke can be suppressed.
《効果4》 排気(9)の昇温効率が高い。
このエンジンと異なる構造、すなわち排気絞り弁(5)がDPF(7)よりも排気下流側に配置されている場合に比べ、このエンジンでは、図1に例示するように、排気絞り弁(5)がDPF(7)よりも排気上流側に配置されているため、排気絞り弁(5)の排気上流側の排気管(4)の容積が小さくなり、排気絞り弁(5)の開度減少で弁上流側排気圧(P0)が速やかに昇圧し、排気(9)の昇温効率が高い。
<< Effect 4 >> The heating efficiency of the exhaust gas (9) is high.
Compared to the case where the structure different from this engine, that is, the exhaust throttle valve (5) is arranged on the exhaust downstream side of the DPF (7), in this engine, as illustrated in FIG. 1, the exhaust throttle valve (5) Is located on the upstream side of the exhaust gas from the DPF (7), so that the volume of the exhaust pipe (4) on the upstream side of the exhaust gas of the exhaust throttle valve (5) becomes small, and the opening degree of the exhaust throttle valve (5) decreases. The exhaust pressure (P0) on the upstream side of the valve is rapidly increased, and the temperature rise efficiency of the exhaust (9) is high.
《効果5》 排気絞り弁(5)の弁鳴り音が排気管(4)外に放出され難い。
このエンジンでは、図1に例示するように、排気絞り弁(5)の排気下流側に弁下流側DOC(6)とDPF(7)が配置されるため、排気絞り弁(5)の弁鳴り音が排気管(4)外に放出され難い。
<< Effect 5 >> It is difficult for the valve noise of the exhaust throttle valve (5) to be emitted to the outside of the exhaust pipe (4).
In this engine, as illustrated in FIG. 1, since the valve downstream side DOC (6) and the DPF (7) are arranged on the exhaust downstream side of the exhaust throttle valve (5), the valve noise of the exhaust throttle valve (5) Sound is hard to be emitted to the outside of the exhaust pipe (4).
《効果6》 オイルダイリューションが抑制される。
燃料をシリンダ内に噴射するポスト噴射では、シリンダに付着した燃料がエンジンオイルに混入してオイルダイリューションが起こるが、このエンジンでは、ポスト噴射に代えて排気管噴射を行うため、オイルダイリューションが抑制される。
<<
In post-injection, which injects fuel into the cylinder, the fuel adhering to the cylinder mixes with the engine oil and oil dilution occurs. The engine is suppressed.
図1~図4は本発明の実施形態に係るディーゼルエンジンを説明する図で、この実施形態ではコモンレール式の立形直列多気筒ディーゼルエンジンについて説明する。 1 to 4 are views for explaining a diesel engine according to an embodiment of the present invention, and in this embodiment, a common rail type vertical in-line multi-cylinder diesel engine will be described.
このエンジンの構成は、次の通りである。
図1に示すように、クランク軸(21)の架設方向を前後方向、フライホイール(22)の配置された側を後側、その反対側を前側、前後方向と直交するエンジン幅方向を横方向とする。
図1に示すように、このエンジンは、シリンダヘッド(23)の横一側に組みつけられた吸気マニホルド(24)と、シリンダヘッド(23)の横他側に組み付けられた排気マニホルド(25)を備えている。
図1に示すように、このエンジンは、電子制御装置(8)を備えている。
電子制御装置(8)は、エンジンECUである。エンジンECUは、電子制御ユニットの略称で、マイコンである。
The configuration of this engine is as follows.
As shown in FIG. 1, the erection direction of the crank shaft (21) is the front-rear direction, the side where the flywheel (22) is arranged is the rear side, the opposite side is the front side, and the engine width direction orthogonal to the front-rear direction is the lateral direction. And.
As shown in FIG. 1, this engine has an intake manifold (24) assembled on one lateral side of the cylinder head (23) and an exhaust manifold (25) assembled on the other lateral side of the cylinder head (23). It is equipped with.
As shown in FIG. 1, this engine includes an electronic control device (8).
The electronic control device (8) is an engine ECU. The engine ECU is an abbreviation for an electronic control unit and is a microcomputer.
図1に示すように、このエンジンは、排気装置を備えている。
排気装置は、排気マニホルド(25)と、排気マニホルド(25)に接続された過給機(26)の排気タービン(26a)と、排気タービン(26a)の排気出口(26b)から導出された排気導出通路(26c)を備えている。
As shown in FIG. 1, this engine is equipped with an exhaust system.
The exhaust device includes an exhaust manifold (25), an exhaust turbine (26a) of a supercharger (26) connected to the exhaust manifold (25), and an exhaust derived from an exhaust outlet (26b) of the exhaust turbine (26a). It is provided with a lead-out passage (26c).
図1に示すように、このエンジンは、吸気装置を備えている。
吸気装置は、過給機(26)のコンプレッサ(26d)と、コンプレッサ(26d)の吸気入口(26e)の吸気上流側に設けられた吸気流量センサ(16)と、コンプレッサ(26d)の過給気出口(26f)と吸気マニホルド(24)の間に配置されたインタークーラ(28)と、インタークーラ(28)と吸気マニホルド(24)の間に配置された吸気絞り弁(11)と、排気マニホルド(25)と吸気マニホルド(24)の間に配置されたEGRクーラ(30)と、EGRクーラ(30)と吸気マニホルド(24)の間に配置されたEGR弁(31)を備えている。EGRは、排気ガス還流の略称である。
吸気絞り弁(11)とEGR弁(31)は、いずれも電動式開閉弁で、これらは電子制御装置(8)を介して電源(29)に電気的に接続されている。吸気流量センサ(16)は吸気温度センサを備え、電子制御装置(8)に電気的に接続されている。電源(29)はバッテリである。
As shown in FIG. 1, this engine is equipped with an intake system.
The intake device includes a compressor (26d) of a supercharger (26), an intake flow sensor (16) provided on the intake upstream side of the intake inlet (26e) of the compressor (26d), and a supercharge of the compressor (26d). An intercooler (28) arranged between the air outlet (26f) and the intake manifold (24), an intake throttle valve (11) arranged between the intercooler (28) and the intake manifold (24), and an exhaust gas recirculation. It comprises an EGR cooler (30) disposed between the manifold (25) and the intake manifold (24) and an EGR valve (31) disposed between the EGR cooler (30) and the intake manifold (24). EGR is an abbreviation for exhaust gas recirculation.
The intake throttle valve (11) and the EGR valve (31) are both electric on-off valves, and these are electrically connected to the power supply (29) via the electronic control device (8). The intake flow rate sensor (16) includes an intake temperature sensor and is electrically connected to the electronic control device (8). The power source (29) is a battery.
図1に示すように、このエンジンは、コモンレール式の燃料噴射装置(3)を備えている。
この燃料噴射装置(3)は、各燃焼室(1)に設けられた燃料噴射弁(34)と、燃料噴射弁(34)から噴射する燃料を蓄圧するコモンレール(35)と、コモンレール(35)に燃料タンク(36)から燃料を圧送する燃料サプライポンプ(37)を備えている。
燃料噴射弁(34)は電磁式開閉弁を備え、燃料サプライポンプ(37)は、電動式調圧弁を備え、これらは電子制御装置(8)を介して電源(29)に電気的に接続されている。
As shown in FIG. 1, this engine is equipped with a common rail type fuel injection device (3).
The fuel injection device (3) includes a fuel injection valve (34) provided in each combustion chamber (1), a common rail (35) for accumulating fuel injected from the fuel injection valve (34), and a common rail (35). Is equipped with a fuel supply pump (37) that pumps fuel from the fuel tank (36).
The fuel injection valve (34) comprises an electromagnetic on-off valve and the fuel supply pump (37) comprises an electric pressure regulating valve, which are electrically connected to a power source (29) via an electronic control device (8). ing.
図1に示すように、このエンジンは、調速装置を備えている。
調速装置は、エンジンの目標回転数を設定するアクセルレバー(38)の設定位置を検出するアクセルセンサ(39)と、エンジンの実回転数を検出する実回転数センサ(40)を備え、これらセンサ(39)(40)は電子制御装置(8)に電気的に接続されている。
As shown in FIG. 1, this engine is equipped with a speed governor.
The speed control device includes an accelerator sensor (39) for detecting the set position of the accelerator lever (38) for setting the target rotation speed of the engine, and an actual rotation speed sensor (40) for detecting the actual rotation speed of the engine. The sensors (39) and (40) are electrically connected to the electronic control device (8).
図1に示すように、このエンジンは、始動装置を備えている。
始動装置は、スタータモータ(41)と、キースイッチ(42)を備え、スタータモータ(41)とキースイッチ(42)は、電子制御装置(8)を介して電源(29)に電気的に接続されている。キースイッチ(42)は、OFF位置と、ON位置と、スタート位置を備えている。
As shown in FIG. 1, this engine is equipped with a starter.
The starting device comprises a starter motor (41) and a key switch (42), and the starter motor (41) and the key switch (42) are electrically connected to a power source (29) via an electronic control device (8). Has been done. The key switch (42) has an OFF position, an ON position, and a start position.
電子制御装置(8)は、次のような運転制御を行うように構成されている。
エンジンの目標回転数と実回転数の回転数偏差を小さくするように、燃料噴射弁(34)からの燃料噴射量や噴射タイミングを設定し、負荷変動によるエンジンの回転数変動を小さくする。
エンジンの回転数と負荷と吸気量と吸気温度に応じ、吸気絞り弁(11)とEGR弁(31)の開度を調節し、吸気量やEGR率を調節する。
キースイッチ(42)がスタート位置に投入されると、スタータモータ(41)を駆動し、エンジンの始動を行う。キースイッチ(42)がON位置に投入されると、電源(29)からエンジン各部への通電により、エンジン運転状態が維持され、キースイッチ(42)がOFF位置に投入されると、燃料噴射弁(34)からの燃料噴射が停止され、エンジンが停止される。
The electronic control device (8) is configured to perform the following operation control.
The fuel injection amount and injection timing from the fuel injection valve (34) are set so as to reduce the rotation speed deviation between the target rotation speed and the actual rotation speed of the engine, and the rotation speed fluctuation of the engine due to the load fluctuation is reduced.
The opening degrees of the intake throttle valve (11) and the EGR valve (31) are adjusted according to the engine rotation speed, the load, the intake amount, and the intake temperature, and the intake amount and the EGR rate are adjusted.
When the key switch (42) is turned on to the start position, the starter motor (41) is driven to start the engine. When the key switch (42) is turned on to the ON position, the engine operating state is maintained by energizing each part of the engine from the power supply (29), and when the key switch (42) is turned on to the OFF position, the fuel injection valve The fuel injection from (34) is stopped and the engine is stopped.
このエンジンは、排気処理装置を備えている。
図1に示すように、排気処理装置は、燃焼室(1)に燃料(2)を噴射する燃料噴射装置(3)と、燃焼室(1)の排気下流側の排気管(4)内に燃料(2)を噴射する排気管インジェクタ(3a)と、排気管(4)内に配置された排気絞り弁(5)と、その排気下流側に配置された弁下流側DOC(6)と、その排気下流側に配置されたDPF(7)と、排気絞り弁(5)の開度と燃料噴射装置(3)及び排気管インジェクタ(3a)の燃料噴射を制御する電子制御装置(8)を備えている。
排気管インジェクタ(3a)は、コモンレール(35)に接続され、電子制御装置(8)で開閉制御される。
排気管インジェクタ(3a)は、コモンレール(35)とは別の燃料噴射機構(例えば燃料噴射ポンプ)に接続されたものであってもよい。燃料噴射弁(34)もコモンレール式でない燃料噴射機構(例えば燃料噴射ポンプ)に接続されたものであってもよい。
This engine is equipped with an exhaust treatment device.
As shown in FIG. 1, the exhaust treatment device is provided in a fuel injection device (3) for injecting fuel (2) into a combustion chamber (1) and in an exhaust pipe (4) on the exhaust downstream side of the combustion chamber (1). An exhaust pipe injector (3a) for injecting fuel (2), an exhaust throttle valve (5) arranged in the exhaust pipe (4), and a valve downstream side DOC (6) arranged on the exhaust downstream side thereof. The DPF (7) arranged on the downstream side of the exhaust, the opening degree of the exhaust throttle valve (5), the fuel injection device (3), and the electronic control device (8) for controlling the fuel injection of the exhaust pipe injector (3a) are provided. I have.
The exhaust pipe injector (3a) is connected to the common rail (35) and is controlled to open and close by the electronic control device (8).
The exhaust pipe injector (3a) may be connected to a fuel injection mechanism (for example, a fuel injection pump) different from the common rail (35). The fuel injection valve (34) may also be connected to a fuel injection mechanism (for example, a fuel injection pump) that is not a common rail type.
このエンジンと異なる構成、すなわち排気絞り弁(5)がDPF(7)よりも排気下流側に配置されている場合に比べ、このエンジンでは、図1に示すように、排気絞り弁(5)がDPF(7)よりも排気上流側に配置されているため、排気絞り弁(5)の排気上流側の排気管(4)の容積が小さくなり、排気絞り弁(5)の開度減少で弁上流側排気圧(P0)が速やかに昇圧し、排気(9)の昇温効率が高い。
また、このエンジンでは、図1に示すように、排気絞り弁(5)の排気下流側に弁下流側DOC(6)とDPF(7)が配置されるため、排気絞り弁(5)の弁鳴り音が排気管(4)外に放出され難い。
また、燃料をシリンダ内に噴射するポスト噴射では、シリンダに付着した燃料がエンジンオイルに混入してオイルダイリューションが起こるが、このエンジンでは、ポスト噴射に代えて排気管噴射を行うため、オイルダイリューションが抑制される。
Compared to the case where the exhaust throttle valve (5) is arranged on the exhaust downstream side of the DPF (7), which is different from this engine, in this engine, the exhaust throttle valve (5) is provided as shown in FIG. Since it is located on the exhaust upstream side of the DPF (7), the volume of the exhaust pipe (4) on the exhaust upstream side of the exhaust throttle valve (5) becomes smaller, and the valve is reduced by reducing the opening degree of the exhaust throttle valve (5). The upstream exhaust pressure (P0) is rapidly increased, and the temperature rise efficiency of the exhaust (9) is high.
Further, in this engine, as shown in FIG. 1, since the valve downstream side DOC (6) and the DPF (7) are arranged on the exhaust downstream side of the exhaust throttle valve (5), the valve of the exhaust throttle valve (5). It is difficult for the noise to be emitted to the outside of the exhaust pipe (4).
Further, in the post injection in which the fuel is injected into the cylinder, the fuel adhering to the cylinder is mixed with the engine oil and oil dilution occurs. However, in this engine, the exhaust pipe injection is performed instead of the post injection, so the oil Dilution is suppressed.
上記各要素について説明する。
図1に示す燃焼室(1)は、シリンダ内に形成されている。燃料(2)は軽油である。排気絞り弁(5)は、電動式開閉弁で、電子制御装置(8)を介して電源(29)に電気的に接続されている。DOCは、ディーゼル酸化触媒の略称で、セラミックハニカム担体に白金やパラジウム等の酸化触媒成分が担持されたスルーフロー型で、排気(9)中のCO(一酸化炭素)及び、NO(一酸化窒素)を酸化する。DPFは、ディーゼル・パティキュレート・フィルタの略称で、セラミックハニカムの隣り合うセルの出入口を交互に塞いだウォールフロー型で、排気(9)中のPMを捕捉する。PMは、粒子状物質の略称である。
弁下流側DOC(6)とDPF(7)は、排気管(4)の途中に配置された排気処理ケース(4a)の排気上流側と下流側にそれぞれ収容されている。
Each of the above elements will be described.
The combustion chamber (1) shown in FIG. 1 is formed in a cylinder. The fuel (2) is light oil. The exhaust throttle valve (5) is an electric on-off valve, which is electrically connected to the power supply (29) via the electronic control device (8). DOC is an abbreviation for diesel oxidation catalyst, which is a through-flow type in which an oxidation catalyst component such as platinum or palladium is supported on a ceramic honeycomb carrier, and CO (carbon monoxide) and NO (nitric oxide) in the exhaust (9). ) Is oxidized. DPF is an abbreviation for diesel particulate filter, which is a wall flow type that alternately blocks the entrance and exit of adjacent cells of ceramic honeycomb, and captures PM in the exhaust gas (9). PM is an abbreviation for particulate matter.
The valve downstream side DOC (6) and DPF (7) are housed in the exhaust upstream side and the exhaust downstream side of the exhaust treatment case (4a) arranged in the middle of the exhaust pipe (4), respectively.
このDPFシステムは、DPF(7)で排気(9)中のPMを捕捉し、排気(9)中のNO(一酸化窒素)を弁下流側DOC(6)で酸化して得られるNO2(二酸化窒素)で、DPF(7)に堆積したPMを比較的低温で連続的に酸化燃焼させるとともに、排気管インジェクタ(3a)から噴射された排気管噴射燃料によって排気(9)に供給された未燃燃料を弁下流側DOC(6)で触媒燃焼させ、DPF(7)に堆積したPMを、比較的高温で燃焼させて、DPF(7)を再生する。 This DPF system captures the PM in the exhaust (9) with the DPF (7) and oxidizes NO (nitrogen monoxide) in the exhaust (9) with the DOC (6) on the downstream side of the valve to obtain NO 2 ( The PM deposited on the DPF (7) is continuously oxidatively combusted at a relatively low temperature with nitrogen dioxide), and is not supplied to the exhaust (9) by the exhaust pipe injection fuel injected from the exhaust pipe injector (3a). The fuel fuel is catalytically burned at the DOC (6) on the downstream side of the valve, and the PM deposited on the DPF (7) is burned at a relatively high temperature to regenerate the DPF (7).
この排気処理装置は、DPF(7)の再生処理のため、次の構成を備えている。
図2に示すように、DPF(7)の再生処理では、PMが堆積したDPF(7)の再生処理の開始条件(S1)が成立した後に排気絞り弁(5)の開度減少制御(S2)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後に燃料噴射装置(3)のアフター噴射制御が開始(S5)され、アフター噴射燃料の燃焼で排気(9)が所定の排気管噴射許可温度(TP)以上の温度になった後に排気管噴射制御が開始(S7)され、図1に例示する排気管インジェクタ(3a)から排気管(4)内に噴射された排気管噴射燃料の弁下流側DOC(6)での触媒燃焼で昇温した排気(9)で、DPF(7)に堆積したPMが焼却されるように構成されている。
This exhaust gas treatment device has the following configuration for the regeneration processing of the DPF (7).
As shown in FIG. 2, in the regeneration process of the DPF (7), the opening degree reduction control (S2) of the exhaust throttle valve (5) is performed after the start condition (S1) of the regeneration process of the DPF (7) in which PM is deposited is satisfied. ) Is performed, and after the exhaust (9) reaches a temperature equal to or higher than the predetermined after-injection permitted temperature (TA), the after-injection control of the fuel injection device (3) is started (S5), and the exhaust (S5) is exhausted by the combustion of the after-injection fuel. Exhaust pipe injection control is started (S7) after 9) reaches a temperature equal to or higher than a predetermined exhaust pipe injection permitted temperature (TP), and the exhaust pipe injector (3a) illustrated in FIG. 1 is inserted into the exhaust pipe (4). The PM deposited in the DPF (7) is incinerated by the exhaust gas (9) whose temperature has been raised by the catalytic combustion at the DOC (6) on the downstream side of the valve of the injected exhaust pipe injection fuel.
このエンジンでは、次の利点がある。
図2に示すように、DPF(7)の再生処理の開始条件(S1)が成立後に排気絞り弁(5)の開度減少による背圧の上昇、及びアフター噴射燃料の燃焼が起こるため、吸気絞りの場合に比べ、排気(9)の昇温効率が高く、排気温度が低い無負荷及び/又は軽負荷運転時でも、図1に示す弁下流側DOC(6)が活性化され、排気管噴射で、DPF(7)を再生できる。
This engine has the following advantages:
As shown in FIG. 2, after the start condition (S1) of the regeneration process of the DPF (7) is satisfied, the back pressure increases due to the decrease in the opening degree of the exhaust throttle valve (5) and the after-injection fuel burns. Compared with the case of throttle, the temperature rise efficiency of the exhaust (9) is high, and even during no-load and / or light-load operation where the exhaust temperature is low, the valve downstream side DOC (6) shown in FIG. 1 is activated and the exhaust pipe. DPF (7) can be regenerated by injection.
また、このエンジンでは、アフター噴射燃料の燃焼で排気(9)が昇温するため、図1に示す排気絞り弁(5)の開度減少の度合いが小さくて済み、背圧による出力ロスが小さく、エンジン出力を高くできる。 Further, in this engine, since the exhaust (9) is heated by the combustion of the after-injection fuel, the degree of decrease in the opening degree of the exhaust throttle valve (5) shown in FIG. 1 is small, and the output loss due to the back pressure is small. , The engine output can be increased.
このエンジンでは、排気温度が低い無負荷及び/又は軽負荷運転の継続で、弁下流側DOC(6)に未燃焼燃料やPMからなる未燃焼堆積物が堆積し、その触媒機能が低下している場合でも、図2に示すように、DPF(7)の再生処理の開始条件(S1)が成立した場合には、排気絞り弁(5)の開度減少やアフター噴射で、排気(9)が昇温し、未燃焼堆積物が気化或いは燃焼され、DPF(7)再生時に図1に示す弁下流側DOC(6)の低下した触媒機能を回復できる。 In this engine, unburned deposits consisting of unburned fuel and PM are deposited on the DOC (6) on the downstream side of the valve due to the continuation of no-load and / or light-load operation with a low exhaust temperature, and its catalytic function deteriorates. Even if it is, as shown in FIG. 2, when the start condition (S1) of the regeneration process of the DPF (7) is satisfied, the opening of the exhaust throttle valve (5) is reduced or the after injection is performed to exhaust (9). The temperature rises, the unburned deposits are vaporized or burned, and the reduced catalytic function of the valve downstream DOC (6) shown in FIG. 1 can be restored during DPF (7) regeneration.
DPF(7)の再生の場合の各要素について説明する。
図2に示すように、DPF(7)の再生処理の開始条件(S1)は、DPF(7)に堆積したPM堆積量推定値(APM)がDPF(7)の再生処理の開始判定値(RSJ)以上になった場合に成立する。PM堆積量推定値(APM)としては、例えば、図1に示すDPF(7)の出入口間の差圧(ΔP)に基づいて、PM堆積量推定値演算装置(32)が推定する方法等がある。PM堆積量推定値演算装置(32)は、電子制御装置(8)の演算部で構成されている。
Each element in the case of regeneration of DPF (7) will be described.
As shown in FIG. 2, the start condition (S1) of the regeneration process of the DPF (7) is such that the estimated PM deposition amount (APM) deposited on the DPF (7) is the start determination value (7) of the regeneration process of the DPF (7). RSJ) It is established when it becomes more than. As the PM accumulation amount estimation value (APM), for example, a method of estimation by the PM accumulation amount estimation value calculation device (32) based on the differential pressure (ΔP) between the entrance and exit of the DPF (7) shown in FIG. 1 may be used. be. The PM deposit amount estimation value calculation device (32) is composed of a calculation unit of the electronic control device (8).
燃料噴射装置(3)から一燃焼サイクル中に行われる噴射の種類には、ブレ噴射(パイロット噴射)と、メイン噴射と、アフター噴射がある。
一燃焼サイクルは、4サイクルエンジンでは、吸気行程と圧縮行程と膨張行程と排気行程からなる。
ブレ噴射(パイロット噴射)は、メイン噴射燃料の着火遅れを抑制するための噴射で、吸気行程中または圧縮行程中に開始される。
メイン噴射は、出力を得るための主たる噴射で、圧縮上死点前に開始される。
アフター噴射は、排気(9)を昇温させるための噴射で、メイン噴射の後、膨張行程中に開始される。
排気管噴射は、排気(9)を昇温させるための噴射で、排気管インジェクタ(3a)から噴射される。
The types of injection performed from the fuel injection device (3) during one combustion cycle include blur injection (pilot injection), main injection, and after injection.
In a four-stroke engine, one combustion cycle consists of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.
The blur injection (pilot injection) is an injection for suppressing the ignition delay of the main injection fuel, and is started during the intake stroke or the compression stroke.
The main injection is the main injection for obtaining output and is started before the compression top dead center.
The after injection is an injection for raising the temperature of the exhaust gas (9), and is started during the expansion stroke after the main injection.
The exhaust pipe injection is an injection for raising the temperature of the exhaust (9), and is injected from the exhaust pipe injector (3a).
図2に示すDPF(7)の再生処理の場合、アフター噴射は次のように設定されている。
アフター噴射許可温度(TA)は、150°C以上、700°C以下に設定する。
アフター噴射制御では、図1に示す弁下流側DOC(6)の入口側排気温度(T1)が400°C以上、700°C以下(望ましくは450°以上、500°以下)に維持されるように設定されている。
In the case of the regeneration process of the DPF (7) shown in FIG. 2, the after injection is set as follows.
The after-injection allowable temperature (TA) is set to 150 ° C or higher and 700 ° C or lower.
In the after injection control, the inlet side exhaust temperature (T1) of the valve downstream side DOC (6) shown in FIG. 1 is maintained at 400 ° C or higher and 700 ° C or lower (preferably 450 ° or higher and 500 ° or lower). Is set to.
アフター噴射許可温度(TA)は、弁上流側排気温度センサ(19)で検出される弁上流側排気温度(T0)についての判定温度であり、弁上流側排気温度(T0)は、弁上流側排気温度センサ(19)で検出され、電子制御装置(8)による噴射タイミングや燃料噴射量の調節によって制御される。
弁下流側DOC(6)の入口側排気温度(T1)は、DOC入口側排気温度センサ(43)で検出され、電子制御装置(8)による噴射タイミングや燃料噴射量の調節によって制御される。弁下流側DOC(6)の入口側排気温度(T1)は、弁上流側排気温度センサ(19)で検出される弁上流側排気温度(T0)から推定されるものであってもよい。
The after-injection permit temperature (TA) is a determination temperature for the valve upstream side exhaust temperature (T0) detected by the valve upstream side exhaust temperature sensor (19), and the valve upstream side exhaust temperature (T0) is the valve upstream side exhaust gas temperature (T0). It is detected by the exhaust temperature sensor (19) and controlled by the adjustment of the injection timing and the fuel injection amount by the electronic control device (8).
The inlet side exhaust temperature (T1) of the valve downstream side DOC (6) is detected by the DOC inlet side exhaust temperature sensor (43) and is controlled by adjusting the injection timing and the fuel injection amount by the electronic control device (8). The inlet side exhaust temperature (T1) of the valve downstream side DOC may be estimated from the valve upstream side exhaust temperature (T0) detected by the valve upstream side exhaust temperature sensor (19).
アフター噴射許可温度(TA)は、150°C以上、250°C未満が望ましく、150°C以上、200°C未満がより望ましい。
アフター噴射許可温度(TA)が150°C程度の低い温度でよい理由は、次の通りである。
すなわち、排気絞り弁(5)の排気絞りにより、その上流側の排気圧をゲージ圧で80kPa以上、120kPa以下(絶対圧で181.32kPa以上、221.23kPa以下)に設定すると、その排気圧が大気圧101.32kPaの約2倍となり、150°C程度の低い温度でも弁上流側DOC(17)が活性化し、弁上流側DOC(17)でアフター噴射燃料の酸化反応(触媒燃焼)が起こるためである。
The after-injection allowable temperature (TA) is preferably 150 ° C or higher and lower than 250 ° C, and more preferably 150 ° C or higher and lower than 200 ° C.
The reason why the after-injection allowable temperature (TA) may be as low as about 150 ° C. is as follows.
That is, when the exhaust pressure on the upstream side is set to 80 kPa or more and 120 kPa or less (absolute pressure 181.32 kPa or more and 221.23 kPa or less) by the exhaust throttle of the exhaust throttle valve (5), the exhaust pressure is increased. It becomes about twice the atmospheric pressure 101.32 kPa, the valve upstream side DOC (17) is activated even at a low temperature of about 150 ° C, and the after injection fuel oxidation reaction (catalytic combustion) occurs at the valve upstream side DOC (17). Because.
アフター噴射では、膨張行程で燃焼室(1)内に噴射が開始されたアフター噴射燃料が排気(9)の熱で燃焼し、無負荷及び低負荷運転で排気(9)の温度が低い場合でも、排気(9)が弁下流側DOC(6)に堆積する未燃焼堆積物が気化または焼却される温度まで昇温され、未燃焼堆積物で低下した弁下流側DOC(6)の触媒機能が回復すると共に、弁下流側DOC(6)が活性化される。 In the after-injection, the after-injection fuel whose injection is started in the combustion chamber (1) in the expansion stroke burns with the heat of the exhaust (9), and even when the temperature of the exhaust (9) is low in the no-load and low-load operation. , The exhaust gas (9) is heated to the temperature at which the unburned deposits deposited on the valve downstream DOC (6) are vaporized or incinerated, and the catalytic function of the valve downstream DOC (6) lowered by the unburned deposits As it recovers, the valve downstream DOC (6) is activated.
図2に示すDPF(7)の再生処理の場合、排気管噴射は次のように設定されている。
排気管噴射許可温度(TP)は、200°C以上、700°C以下に設定されている。
排気管噴射許可温度(TP)は、アフター噴射許可温度(TA)よりも高い温度に設定されている。
排気管噴射制御では、弁下流側DOC(6)の入口側排気温度(T1)が400°C以上、700°C以下に維持されると共に、DPF(7)の入口側排気温度(T2)が550°C以上、700°C以下に維持されるように設定されている。特に、DPF(7)の入口側排気温度(T2)は、堆積したPMの異常燃焼を防止するため、700°C以下に設定することが望ましい。
排気管噴射許可温度(TP)は、弁上流側排気温度センサ(19)で検出される弁上流側排気温度(T0)についての判定温度であり、弁上流側排気温度(T0)は、弁上流側排気温度センサ(19)で検出され、電子制御装置(8)で制御される。
弁下流側DOC(6)の入口側排気温度(T1)は、弁上流側排気温度センサ(19)で検出される弁上流側排気温度(T0)により、電子制御装置(8)による噴射タイミングや燃料噴射量の調節によって制御される。
DPF(7)の入口側排気温度(T2)は、DPF入口側排気温度センサ(27)で検出され、電子制御装置(8)による噴射タイミングや燃料噴射量の調節によって制御される。
なお、DPF出口側排気温度センサ(33)で検出されるDPF出口側排気温度(T3)が所定の上限温度以上の温度になった場合には、電子制御装置(8)の制御によりアフター噴射や排気管噴射は緊急停止される。
排気管噴射では、排気管(4)内に噴射が開始された排気管噴射燃料が弁下流側DOC(6)で触媒燃焼し、排気(9)が昇温し、DPF(7)に溜まったPMが焼却除去される。
In the case of the regeneration process of the DPF (7) shown in FIG. 2, the exhaust pipe injection is set as follows.
The exhaust pipe injection permitted temperature (TP) is set to 200 ° C. or higher and 700 ° C. or lower.
The exhaust pipe injection permitted temperature (TP) is set to a temperature higher than the after injection permitted temperature (TA).
In the exhaust pipe injection control, the inlet side exhaust temperature (T1) of the valve downstream side DOC (6) is maintained at 400 ° C or higher and 700 ° C or lower, and the inlet side exhaust temperature (T2) of the DPF (7) is maintained. It is set to be maintained at 550 ° C or higher and 700 ° C or lower. In particular, the inlet side exhaust temperature (T2) of the DPF (7) is preferably set to 700 ° C. or lower in order to prevent abnormal combustion of the accumulated PM.
The exhaust pipe injection permitted temperature (TP) is a determination temperature for the valve upstream side exhaust temperature (T0) detected by the valve upstream side exhaust temperature sensor (19), and the valve upstream side exhaust temperature (T0) is the valve upstream side exhaust temperature (T0). It is detected by the side exhaust temperature sensor (19) and controlled by the electronic control device (8).
The inlet side exhaust temperature (T1) of the valve downstream side DOC is determined by the injection timing by the electronic control device (8) according to the valve upstream side exhaust temperature (T0) detected by the valve upstream side exhaust temperature sensor (19). It is controlled by adjusting the fuel injection amount.
The inlet side exhaust temperature (T2) of the DPF (7) is detected by the DPF inlet side exhaust temperature sensor (27) and is controlled by adjusting the injection timing and the fuel injection amount by the electronic control device (8).
When the DPF outlet side exhaust temperature (T3) detected by the DPF outlet side exhaust temperature sensor (33) reaches a temperature equal to or higher than a predetermined upper limit temperature, after injection or after injection is performed under the control of the electronic control device (8). Exhaust pipe injection is stopped urgently.
In the exhaust pipe injection, the exhaust pipe injection fuel that has been started to be injected into the exhaust pipe (4) is catalytically burned at the DOC (6) on the downstream side of the valve, the exhaust (9) is heated, and is accumulated in the DPF (7). PM is incinerated and removed.
このエンジンは、図1に示すように、吸気経路(10)に配置された吸気絞り弁(11)を備え、その開度が電子制御装置(8)で制御されるように構成され、図2に示すDPF(7)の再生処理又は図3に示す弁下流側DOC(6)の触媒機能回復処理では、DPF(7)の再生処理の開始条件(S1)が成立した後、又は弁下流側DOC(6)の触媒機能回復処理の開始条件(13)が成立した後は、排気絞り弁(5)の開度減少制御(S2)(S15)がなされると共に、吸気絞り弁(11)の開度減少制御(S2)(S15)がなされるように構成されている。
このため、このエンジンでは、排気絞りと共に吸気絞りが行われるため、吸気量の減少により排気(9)の昇温効率が高まる。
As shown in FIG. 1, this engine includes an intake throttle valve (11) arranged in an intake path (10), and the opening degree thereof is controlled by an electronic control device (8). FIG. In the regeneration treatment of the DPF (7) shown in FIG. 3 or the catalytic function recovery treatment of the valve downstream side DOC (6) shown in FIG. 3, after the start condition (S1) of the regeneration treatment of the DPF (7) is satisfied, or on the valve downstream side. After the start condition (13) of the catalytic function recovery process of the DOC (6) is satisfied, the opening degree reduction control (S2) (S15) of the exhaust throttle valve (5) is performed, and the intake throttle valve (11) is operated. It is configured so that the opening degree reduction control (S2) (S15) is performed.
Therefore, in this engine, the intake throttle is performed together with the exhaust throttle, so that the efficiency of raising the temperature of the exhaust (9) is increased by reducing the intake amount.
このエンジンでは、図2または図3に示すように、排気絞り弁(5)の開度減少制御(S2)(S15)がなされた後、弁上流側排気圧(P0)が所定の圧力上限値(Pmax)を超えた場合には、その後に排気絞り弁(5)の開度増加制御(S4-2)(S17-2)がなされるように構成されている。
このため、このエンジンでは、弁上流側排気圧(P0)の過剰な昇圧が抑制されるため、その加圧で排気絞り弁(5)やその上流側の部品が故障し難い。
圧力上限値(Pmax)は、図1に示す排気絞り弁(5)、EGR弁(31)、過給機(26)等の仕様又は排気管(4)の配管の気密性などから決められる。
排気絞り弁(5)は、排気管(4)の途中に配置されている。
圧力上限値(Pmax)は、ゲージ圧で80kPa以上、120kPa以下とするのが望ましく、100kPaとするのがより望ましい。
In this engine, as shown in FIG. 2 or 3, after the opening degree reduction control (S2) (S15) of the exhaust throttle valve (5) is performed, the valve upstream side exhaust pressure (P0) becomes a predetermined pressure upper limit value. When (Pmax) is exceeded, the opening degree increase control (S4-2) (S17-2) of the exhaust throttle valve (5) is subsequently performed.
Therefore, in this engine, excessive boosting of the exhaust pressure on the upstream side of the valve (P0) is suppressed, so that the pressurization does not easily cause the exhaust throttle valve (5) and the parts on the upstream side to break down.
The pressure upper limit value (Pmax) is determined from the specifications of the exhaust throttle valve (5), the EGR valve (31), the supercharger (26), etc. shown in FIG. 1, or the airtightness of the exhaust pipe (4).
The exhaust throttle valve (5) is arranged in the middle of the exhaust pipe (4).
The upper limit of the pressure (Pmax) is preferably 80 kPa or more and 120 kPa or less in gauge pressure, and more preferably 100 kPa.
このエンジンでは、図1に示すように、弁上流側排気圧(P0)の演算装置(12)を備え、図4に示すように、弁上流側排気圧(P0)は、排気(9)の質量流量(G)と、弁上流側排気温度(T0)と、弁下流側排気圧(P1)から演算で算出されるように構成されている。弁上流側排気圧(P0)の演算装置(12)は、電子制御装置(8)の演算部で構成されている。 As shown in FIG. 1, this engine includes a calculation device (12) for the valve upstream side exhaust pressure (P0), and as shown in FIG. 4, the valve upstream side exhaust pressure (P0) is the exhaust (9). It is configured to be calculated from the mass flow rate (G), the valve upstream side exhaust temperature (T0), and the valve downstream side exhaust pressure (P1). The arithmetic unit (12) of the valve upstream exhaust pressure (P0) is composed of the arithmetic unit of the electronic control device (8).
このエンジンでは、図4に示すように、排気(9)の質量流量(G)等から演算で弁上流側排気圧(P0)を精度よく算出できるため、図1に示す排気絞り弁(5)の制御精度を高くできる。 In this engine, as shown in FIG. 4, since the exhaust pressure (P0) on the upstream side of the valve can be accurately calculated from the mass flow rate (G) of the exhaust (9) and the like, the exhaust throttle valve (5) shown in FIG. Control accuracy can be increased.
このエンジンでは、弁上流側排気圧(P0)は、排気絞り弁(5)の排気上流側に配置した排気圧センサで検出してもかまわない。この場合、弁上流側排気圧(P0)を迅速に検出できるため、図1に示す排気絞り弁(5)の制御精度を高くできる。 In this engine, the exhaust pressure on the upstream side of the valve (P0) may be detected by an exhaust pressure sensor arranged on the upstream side of the exhaust of the exhaust throttle valve (5). In this case, since the exhaust pressure (P0) on the upstream side of the valve can be quickly detected, the control accuracy of the exhaust throttle valve (5) shown in FIG. 1 can be improved.
弁上流側排気圧(P0)を演算で算出する場合には、次の関係式を用いることができる。
弁上流側排気圧(P0)は、図4の式1により、排気(9)の質量流量(G)と、弁上流側排気温度(T0)と、弁下流側排気圧(P1)から演算で算出することができる。
排気(9)の質量流量(G)は、図4の式2により、排気(9)の密度(ρ0)と排気(9)の体積流量(V)から演算で算出することができる。
排気(9)の体積流量(V)は、図4の式3により、排気(9)の質量流量(G)と燃料噴射量(Q)等から演算で算出することができる。
燃料噴射量(Q)は、1秒当たりのブレ噴射(パイロット噴射)と、メイン噴射と、アフター噴射と、排気管噴射を加算した燃料噴射量である。
When calculating the valve upstream exhaust pressure (P0) by calculation, the following relational expression can be used.
The valve upstream exhaust pressure (P0) is calculated from the mass flow rate (G) of the exhaust (9), the valve upstream exhaust temperature (T0), and the valve downstream exhaust pressure (P1) according to
The mass flow rate (G) of the exhaust gas (9) can be calculated by calculation from the density (ρ0) of the exhaust gas (9) and the volume flow rate (V) of the exhaust gas (9) by the
The volumetric flow rate (V) of the exhaust (9) can be calculated by calculation from the mass flow rate (G) of the exhaust (9), the fuel injection amount (Q), and the like according to the
The fuel injection amount (Q) is the fuel injection amount obtained by adding the blur injection (pilot injection), the main injection, the after injection, and the exhaust pipe injection per second.
なお、排気流量の代用値として吸気流量を用いることができるため、図4の式3の精密な排気(9)の体積流量(V)の演算に代え、吸気流量センサ(16)で計量された吸気流量を排気(9)の体積流量(V)とみなして、式2の演算を行ってもよい。
Since the intake flow rate can be used as a substitute value for the exhaust flow rate, it was measured by the intake flow rate sensor (16) instead of the precise calculation of the volume flow rate (V) of the exhaust (9) in FIG. The calculation of
このエンジンでは、図1に示すように、DPF(7)の出入口間の差圧(ΔP)を検出する差圧センサ(13)と、大気圧(P3)を検出する大気圧センサ(14)を備え、図4の式4に示すように、弁下流側排気圧(P1)は、DPF(7)の出入口間の差圧(ΔP)と大気圧(P3)から演算で算出されるように構成されている。 In this engine, as shown in FIG. 1, a differential pressure sensor (13) for detecting the differential pressure (ΔP) between the entrance and exit of the DPF (7) and an atmospheric pressure sensor (14) for detecting the atmospheric pressure (P3) are used. As shown in Equation 4 of FIG. 4, the valve downstream exhaust pressure (P1) is configured to be calculated from the differential pressure (ΔP) between the inlet and outlet of the DPF (7) and the atmospheric pressure (P3). Has been done.
このエンジンでは、図4に示すように、DPF(7)の出入口間の差圧(ΔP)と大気圧(P3)から演算で弁下流側排気圧(P1)を精度よく算出できるため、図1に示す排気絞り弁(5)の制御精度を高くできる。 In this engine, as shown in FIG. 4, the exhaust pressure on the downstream side of the valve (P1) can be accurately calculated from the differential pressure (ΔP) between the entrance and exit of the DPF (7) and the atmospheric pressure (P3). The control accuracy of the exhaust throttle valve (5) shown in the above can be improved.
このエンジンでは、弁下流側排気圧(P1)を排気絞り弁(5)の排気下流側に配置した排気圧センサで検出してもかまわない。この場合、弁下流側排気圧(P1)を迅速に検出できるため、図1に示す排気絞り弁(5)の制御精度を高くできる。 In this engine, the exhaust pressure on the downstream side of the valve (P1) may be detected by the exhaust pressure sensor arranged on the downstream side of the exhaust of the exhaust throttle valve (5). In this case, since the exhaust pressure (P1) on the downstream side of the valve can be quickly detected, the control accuracy of the exhaust throttle valve (5) shown in FIG. 1 can be improved.
このエンジンでは、図1に示すように、弁上流側排気温度センサ(19)を備え、図4に示すように、これで検出される弁上流側排気温度(T0)が、弁上流側排気圧(P0)の演算に用いられていると共に、図2に示すように、アフター噴射許可温度(TA)及び排気管噴射許可温度(TP)との温度比較判定にも用いられている。 As shown in FIG. 1, this engine is provided with a valve upstream side exhaust temperature sensor (19), and as shown in FIG. 4, the valve upstream side exhaust temperature (T0) detected by the sensor is the valve upstream side exhaust pressure. In addition to being used in the calculation of (P0), as shown in FIG. 2, it is also used in the temperature comparison determination between the after injection permitted temperature (TA) and the exhaust pipe injection permitted temperature (TP).
このエンジンでは、単一の弁上流側排気温度センサ(19)で検出した弁上流側排気温度(T0)を用いて、上記演算と比較判定を行うため、センサの数を少なくできる。 In this engine, the number of sensors can be reduced because the above calculation and the comparison determination are performed using the valve upstream side exhaust temperature (T0) detected by the single valve upstream side exhaust temperature sensor (19).
このエンジンでは、弁上流側排気圧(P0)を排気絞り弁(5)の排気上流側に排気した排気圧センサで検出し、アフター噴射許可温度(TA)の比較判定に弁上流側排気温度センサ(19)の検出温度を用い、排気管噴射許可温度(TP)の比較判定に弁下流側排気温度センサの検出温度を用いてもかまわない。この場合、弁上流側排気圧(P0)の検出、アフター噴射許可温度(TA)の比較判定、排気管噴射許可温度(TP)の比較判定を迅速に行うことができる。 In this engine, the exhaust pressure on the upstream side of the valve (P0) is detected by the exhaust pressure sensor exhausted to the upstream side of the exhaust of the exhaust throttle valve (5), and the exhaust temperature sensor on the upstream side of the valve is used for comparison determination of the after-injection allowable temperature (TA). The detected temperature of (19) may be used, and the detected temperature of the exhaust gas temperature sensor on the downstream side of the valve may be used for the comparison determination of the exhaust pipe injection permitted temperature (TP). In this case, the detection of the valve upstream exhaust pressure (P0), the comparison determination of the after injection allowable temperature (TA), and the comparison determination of the exhaust pipe injection allowable temperature (TP) can be performed quickly.
このエンジンでは、図1に示すように、排気絞り弁(5)の排気上流側に配置される弁上流側DOC(17)を備えている。
このエンジンでは、無負荷及び/又は運転の継続で、弁下流側DOC(6)に未燃焼燃料やPMからなる未燃焼堆積物が堆積し、弁下流側DOC(6)の触媒機能が低下している場合でも、図2に示すように、DPF(7)の再生処理の開始条件(S1)が成立した場合には、その後のアフター噴射により、アフター噴射燃料が弁上流側DOC(17)で触媒燃焼され、排気(9)が大幅に昇温するため、未燃焼堆積物が速やかに気化或いは燃焼し、DPF(7)再生時に図1に示す弁下流側DOC(6)の低下した触媒機能を回復できる。
弁上流側DOC(17)は、排気管(4)の途中に配置された弁上流側DOCケース(4b)内に収容されている。弁上流側排気温度センサ(19)は、弁上流側DOC(17)と排気絞り弁(5)の間に配置されている。
As shown in FIG. 1, this engine includes a valve upstream side DOC (17) arranged on the exhaust upstream side of the exhaust throttle valve (5).
In this engine, with no load and / or continued operation, unburned deposits consisting of unburned fuel and PM are deposited on the valve downstream side DOC (6), and the catalytic function of the valve downstream side DOC (6) deteriorates. Even if this is the case, as shown in FIG. 2, if the start condition (S1) for the regeneration process of the DPF (7) is satisfied, the after-injection fuel is DOC (17) on the upstream side of the valve due to the subsequent after-injection. Since the exhaust (9) is significantly heated by the catalyst combustion, the unburned deposits are rapidly vaporized or burned, and the reduced catalytic function of the valve downstream DOC (6) shown in FIG. 1 during DPF (7) regeneration. Can be recovered.
The valve upstream side DOC (17) is housed in a valve upstream side DOC case (4b) arranged in the middle of the exhaust pipe (4). The valve upstream side exhaust temperature sensor (19) is arranged between the valve upstream side DOC (17) and the exhaust throttle valve (5).
このエンジンでは、図1に示すように、弁上流側DOC(17)と弁下流側DOC(6)には、セル内を排気(9)が通過するハニカム担体に触媒成分を担持させたフロースルー型の酸化触媒が用いられている。
このため、このエンジンでは、図1に示すように、弁上流側DOC(17)と弁下流側DOC(6)にフロースルー型の酸化触媒が用いられているため、背圧による出力ロスが小さく、エンジン出力を高くできる。
In this engine, as shown in FIG. 1, a flow-through in which a catalyst component is supported on a honeycomb carrier through which the exhaust gas (9) passes through the cell in the valve upstream side DOC (17) and the valve downstream side DOC (6). A type of oxidation catalyst is used.
Therefore, in this engine, as shown in FIG. 1, a flow-through type oxidation catalyst is used for the valve upstream side DOC (17) and the valve downstream side DOC (6), so that the output loss due to back pressure is small. , The engine output can be increased.
このエンジンでは、図1に示すように、弁上流側DOC(17)の径は、弁下流側DOC(6)の径よりも小さく形成されている。
このため、エンジンでは、弁上流側DOC(17)のセルを通過する排気(9)の通過速度は、弁下流側DOC(6)のセルを通過する排気(9)の通過速度よりも速くなるため、弁上流側DOC(17)には未燃焼燃料やPMからなる未燃焼堆積物が堆積し難い。
In this engine, as shown in FIG. 1, the diameter of the valve upstream side DOC (17) is formed to be smaller than the diameter of the valve downstream side DOC (6).
Therefore, in the engine, the passing speed of the exhaust gas (9) passing through the cell of the valve upstream DOC (17) is faster than the passing speed of the exhaust gas (9) passing through the cell of the valve downstream DOC (6). Therefore, it is difficult for unburned deposits composed of unburned fuel and PM to accumulate on the DOC (17) on the upstream side of the valve.
このエンジンでは、図1に示すように、弁上流側DOC(17)の(全域の)セル密度は、弁下流側DOC(6)のセル密度よりも大きく形成されている。
このため、このエンジンでは、図1に示すように、弁上流側DOC(17)のセルを通過する排気(9)の通過速度は、弁下流側DOC(6)のセルを通過する排気(9)の通過速度よりも速くなるため、弁上流側DOC(17)には未燃焼燃料やPMからなる未燃焼堆積物が堆積し難い。
In this engine, as shown in FIG. 1, the (overall) cell density of the valve upstream DOC (17) is formed higher than the cell density of the valve downstream DOC (6).
Therefore, in this engine, as shown in FIG. 1, the passing speed of the exhaust gas (9) passing through the cell of the valve upstream side DOC (17) is the exhaust gas (9) passing through the valve downstream side DOC (6) cell. ) Is faster than the passing speed, so that unburned deposits consisting of unburned fuel and PM are unlikely to deposit on the DOC (17) on the upstream side of the valve.
この排気処理装置は、図3に示すように、弁下流側DOC(6)の触媒機能回復処理がなされるように構成され、弁下流側DOC(6)の触媒機能回復処理では、未燃燃料やPMからなる未燃焼堆積物の堆積に基づいて機能低下した弁下流側DOC(6)の触媒機能回復処理の開始条件(S13)が成立した後に排気絞り弁(5)の開度減少制御(S15)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後にアフター噴射制御が開始(S18)され、アフター噴射燃料の燃焼で昇温した排気(9)で、弁下流側DOC(6)に堆積した未燃焼堆積物が気化または焼却されるように構成されている。 As shown in FIG. 3, this exhaust gas treatment device is configured so that the catalytic function recovery treatment of the valve downstream side DOC (6) is performed, and in the catalytic function recovery treatment of the valve downstream side DOC (6), the unburned fuel is used. Control to reduce the opening of the exhaust throttle valve (5) after the conditions (S13) for starting the catalytic function recovery process of the valve downstream DOC (6) whose function has deteriorated due to the accumulation of unburned deposits consisting of fuel and PM are satisfied. After S15) is performed and the exhaust (9) reaches a temperature equal to or higher than the predetermined after-injection permitted temperature (TA), the after-injection control is started (S18), and the exhaust (9) is heated by the combustion of the after-injection fuel. , The unburned deposits deposited on the valve downstream DOC (6) are configured to be vaporized or incinerated.
このエンジンでは、DPF(7)再生時でなくても、図3に示すように、弁下流側DOC(6)の触媒機能回復の開始条件(S13)が成立した後に排気絞り弁(5)の開度減少やアフター噴射で、排気(9)が昇温し、未燃焼堆積物が気化或いは燃焼され、DPF(7)再生前に図1に示す弁下流側DOC(6)の低下した触媒機能が回復され、触媒機能の低下が進行し難い。また、白煙の原因である未燃焼堆積物がないため、白煙の発生も抑えられる。 In this engine, as shown in FIG. 3, after the start condition (S13) for recovering the catalytic function of the valve downstream side DOC (6) is satisfied, the exhaust throttle valve (5) is used even when the DPF (7) is not regenerated. Due to the decrease in opening and after injection, the temperature of the exhaust (9) rises, the unburned deposit is vaporized or burned, and the catalytic function of the valve downstream side DOC (6) shown in FIG. 1 is reduced before the regeneration of the DPF (7). Is recovered, and it is difficult for the catalytic function to decline. In addition, since there is no unburned deposit that causes white smoke, the generation of white smoke is suppressed.
図3に示すように、弁下流側DOC(6)の触媒機能回復処理の開始条件(S13)は、無負荷及び軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)以上になった場合に成立する。無負荷及び軽負荷の運転時間の積算値(tL)は、弁上流側排気温度(T0)が無負荷及び軽負荷運転の判定温度(LJ)以下であることに基づいて、図1に示す運転時間積算装置(18)が算出する。運転時間積算装置(18)は、電子制御装置(8)の演算部で構成されている。 As shown in FIG. 3, the start condition (S13) of the catalytic function recovery process of the valve downstream side DOC (6) is the start of the catalytic function recovery process in which the integrated value (tL) of the operation time of no load and light load is predetermined. It is established when the judgment value (ISJ) or more is reached. The integrated value (tL) of the operation time of no load and light load is the operation shown in FIG. 1 based on the fact that the exhaust gas temperature (T0) on the upstream side of the valve is equal to or less than the determination temperature (LJ) of no load and light load operation. Calculated by the time integration device (18). The operation time integrating device (18) is composed of a calculation unit of the electronic control device (8).
図3に示す弁下流側DOC(6)の触媒機能回復処理の場合、アフター噴射は次のように設定されている。
アフター噴射許可温度(TA)は、150°C以上、700°C以下に設定されている。
アフター噴射制御では、図1に示す弁下流側DOC(6)の入口側排気温度(T1)が180°C以上、700°C以下(望ましくは250°C以上、300°C以下)に維持されるように設定されている。
アフター噴射では、膨張行程で燃焼室内に噴射されたアフター噴射燃料が排気(9)の熱で燃焼し、無負荷及び低負荷運転で排気(9)の温度が低い場合でも、排気(9)が弁下流側DOC(6)に堆積する未燃焼堆積物が気化または焼却される温度まで昇温され、未燃焼堆積物で低下した弁下流側DOC(6)の触媒機能が回復され、触媒機能の低下が進行し難い。
In the case of the catalytic function recovery treatment of the valve downstream side DOC (6) shown in FIG. 3, the after injection is set as follows.
The after-injection allowable temperature (TA) is set to 150 ° C. or higher and 700 ° C. or lower.
In the after injection control, the inlet side exhaust temperature (T1) of the valve downstream side DOC (6) shown in FIG. 1 is maintained at 180 ° C or higher and 700 ° C or lower (preferably 250 ° C or higher and 300 ° C or lower). Is set to.
In the after-injection, the after-injection fuel injected into the combustion chamber in the expansion stroke is burned by the heat of the exhaust (9), and the exhaust (9) is exhausted (9) even when the temperature of the exhaust (9) is low in the no-load and low-load operation. The temperature of the unburned deposits deposited on the downstream side DOC (6) of the valve is raised to the temperature at which it is vaporized or incinerated, and the catalytic function of the downstream side DOC (6) of the valve, which has decreased due to the unburned deposits, is restored and the catalytic function is increased. It is difficult for the decline to progress.
アフター噴射許可温度(TA)は、150°C以上、250°C未満が望ましく、150°C以上、200°C未満がより望ましい。
アフター噴射許可温度(TA)が150°C程度の低い温度でよい理由は、次の通りである。
すなわち、排気絞り弁(5)の排気絞りにより、その上流側の排気圧をゲージ圧で80kPa以上、120kPa以下(絶対圧で181.32kPa以上、221.23kPa以下)に設定すると、その排気圧が大気圧101.32kPaの約2倍となり、150°C程度の低い温度でも弁上流側DOC(17)が活性化し、弁上流側DOC(17)でアフター噴射燃料の酸化反応(触媒燃焼)が起こるためである。
The after-injection allowable temperature (TA) is preferably 150 ° C or higher and lower than 250 ° C, and more preferably 150 ° C or higher and lower than 200 ° C.
The reason why the after-injection allowable temperature (TA) may be as low as about 150 ° C. is as follows.
That is, when the exhaust pressure on the upstream side is set to 80 kPa or more and 120 kPa or less (absolute pressure 181.32 kPa or more and 221.23 kPa or less) by the exhaust throttle of the exhaust throttle valve (5), the exhaust pressure is increased. It becomes about twice the atmospheric pressure 101.32 kPa, the valve upstream side DOC (17) is activated even at a low temperature of about 150 ° C, and the after injection fuel oxidation reaction (catalytic combustion) occurs at the valve upstream side DOC (17). Because.
このエンジンでは、図1に示すように、無負荷及び/又は軽負荷運転の運転時間を積算する運転時間積算装置(18)を備え、図3に示すように、無負荷及び/又は軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合には、弁下流側DOC(6)の触媒機能回復処理の開始条件(S13)が成立するように構成されている。
このため、このエンジンでは、弁下流側DOC(6)の触媒機能の低下の確度が高い時期に、触媒機能の改善を開始できるため、無駄な排気絞りや暖気噴射を無くすことができる。
As shown in FIG. 1, this engine is provided with an operation time integrating device (18) for integrating the operating time of no-load and / or light-load operation, and as shown in FIG. 3, no-load and / or light-load. When the integrated value (tL) of the operation time reaches a predetermined start determination value (ISJ) of the catalytic function recovery process, the start condition (S13) of the catalytic function recovery process of the valve downstream side DOC (6) is satisfied. It is configured as follows.
Therefore, in this engine, improvement of the catalytic function can be started at a time when the probability of deterioration of the catalytic function of the DOC (6) on the downstream side of the valve is high, so that unnecessary exhaust throttle and warm air injection can be eliminated.
図1に示すように、排気絞り弁(5)の排気上流側に配置された弁上流側DOC(17)を備え、図3に示すように、弁下流側DOC(6)の触媒機能回復処理と同様の手順で、弁上流側DOC(17)の触媒機能回復処理がなされるように構成され、弁上流側DOC(17)の触媒機能回復処理では、未燃燃料やPMからなる未燃焼堆積物の堆積に基づいて機能低下した弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立した後に排気絞り弁(5)の開度減少制御(S15)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後にアフター噴射制御が開始(S18)され、アフター噴射燃料の燃焼で昇温した排気(9)の熱で、弁上流側DOC(17)に堆積した未燃焼堆積物が気化または焼却されるように構成されている。 As shown in FIG. 1, a valve upstream side DOC (17) arranged on the exhaust upstream side of the exhaust throttle valve (5) is provided, and as shown in FIG. 3, a catalytic function recovery process of the valve downstream side DOC (6) is provided. In the same procedure as above, the catalytic function recovery treatment of the valve upstream side DOC (17) is configured to be performed, and in the catalytic function recovery treatment of the valve upstream side DOC (17), unburned deposition consisting of unburned fuel and PM is performed. After the start condition (S13) of the catalytic function recovery process of the valve upstream side DOC (17) whose function has deteriorated due to the accumulation of an object is satisfied, the opening degree reduction control (S15) of the exhaust throttle valve (5) is performed and the exhaust (S15) is performed. After injection control is started (S18) after 9) reaches a temperature equal to or higher than the predetermined after-injection permitted temperature (TA), and the heat of the exhaust (9) raised by the combustion of the after-injection fuel causes the valve upstream side DOC. The unburned deposits deposited in (17) are configured to be vaporized or incinerated.
このエンジンでは、排気温度が低い無負荷及び/又は軽負荷運転の継続で、図1に示す弁上流側DOC(17)に未燃焼燃料やPMからなる未燃焼堆積物が堆積し、その触媒機能が低下している場合でも、図3に示すように、弁上流側DOC(17)の触媒機能回復の開始条件(S13)が成立した場合には、図1に示す排気絞り弁(5)の開度減少やアフター噴射の燃焼で、排気(9)が昇温し、この排気(9)の熱で未燃焼堆積物が気化或いは燃焼され、DPF(7)再生前に弁上流側DOC(17)の低下した触媒機能が回復され、触媒機能の低下が進行し難い。このため、無負荷及び/又は軽負荷運転継続時でも、DPF(7)を再生できる。また、白煙の原因である未燃焼堆積物がないため、白煙発生も抑えられる。 In this engine, unburned deposits consisting of unburned fuel and PM are deposited on the DOC (17) on the upstream side of the valve shown in FIG. 1 by continuing no-load and / or light-load operation with a low exhaust temperature, and its catalytic function. As shown in FIG. 3, when the start condition (S13) for recovering the catalytic function of the valve upstream side DOC (17) is satisfied, the exhaust throttle valve (5) shown in FIG. The temperature of the exhaust (9) rises due to the decrease in opening and the combustion of the after-injection, and the heat of the exhaust (9) vaporizes or burns the unburned deposits. ) Decreased catalytic function is restored, and it is difficult for the catalytic function to decline. Therefore, the DPF (7) can be regenerated even when no load and / or light load operation is continued. In addition, since there is no unburned deposit that causes white smoke, the generation of white smoke can be suppressed.
このエンジンでは、アフター噴射燃料の燃焼で図1に示す排気(9)が昇温するため、排気絞り弁(5)の開度減少の度合いが小さくて済み、背圧による出力ロスが小さく、エンジン出力を高くできる。 In this engine, since the exhaust (9) shown in FIG. 1 rises due to the combustion of the after-injection fuel, the degree of decrease in the opening degree of the exhaust throttle valve (5) is small, the output loss due to back pressure is small, and the engine The output can be increased.
このエンジンは、図1に示すように、無負荷及び/又は軽負荷運転の運転時間を積算する運転時間積算装置(18)を備え、図3に示すように、無負荷及び/又は軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合には、弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立するように構成されている。
このため、このエンジンでは、図1に示す弁上流側DOC(17)の触媒機能の低下の確度が高い状況下で触媒機能回復処理を開始できるため、無駄な排気絞りやアフター噴射やポスト噴射を無くすことができる。
As shown in FIG. 1, this engine is provided with an operation time integrating device (18) that integrates the operating time of no-load and / or light-load operation, and as shown in FIG. 3, the no-load and / or light-load operation. When the integrated value (tL) of the operation time reaches a predetermined start determination value (ISJ) of the catalytic function recovery process, the start condition (S13) of the catalytic function recovery process of the valve upstream DOC (17) is satisfied. It is configured as follows.
Therefore, in this engine, the catalytic function recovery process can be started under the condition that the catalytic function of the valve upstream DOC (17) is highly likely to deteriorate as shown in FIG. It can be eliminated.
図3に示す弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)は、無負荷及び/又は軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合に限らず、図1に示す弁上流側排気圧(P0)や、図1に示すDPF(7)の再生処理回数が、所定の触媒機能回復処理の開始判定値に至った場合に成立するようにしてもよい。
このエンジンでは、いずれの場合でも、未燃焼堆積物による弁上流側DOC(17)の触媒機能の低下の確度が高い状況下で、触媒機能回復処理を開始できるため、無駄な排気絞りやアフター噴射やポスト噴射を無くすことができる。
DPF(7)の再生処理を開始条件(S13)とする場合には、電子制御装置(8)で再生処理回数をカウントし、再生処理のカウント数が所定の値(例えば5回)に至った場合には、開始条件(S13)が成立するようにし、触媒機能回復処理か終了すると、再生処理のカウント数を0にリセットする。
As for the start condition (S13) of the catalytic function recovery process of the valve upstream side DOC (17) shown in FIG. 3, the integrated value (tL) of the operation time of no load and / or light load is a predetermined start determination of the catalytic function recovery process. Not only when the value (ISJ) is reached, the valve upstream exhaust pressure (P0) shown in FIG. 1 and the number of regeneration processes of the DPF (7) shown in FIG. 1 are the start determination values of the predetermined catalytic function recovery process. It may be established when it reaches.
In this engine, in any case, the catalytic function recovery process can be started under the condition that the catalytic function of the valve upstream DOC (17) is highly likely to deteriorate due to unburned deposits, so that wasteful exhaust throttle and after-injection can be started. And post injection can be eliminated.
When the regeneration process of the DPF (7) is set as the start condition (S13), the number of regeneration processes is counted by the electronic control device (8), and the count number of the regeneration processes reaches a predetermined value (for example, 5 times). In that case, the start condition (S13) is satisfied, and when the catalytic function recovery process or the end is completed, the count number of the regeneration process is reset to 0.
DPF(7)の再生と触媒機能回復の相違点
図2に示すDPF(7)の再生処理の場合には、図3に示す弁上流側DOC(17)の触媒機能回復処理の場合よりも、DPF(7)の入口側排気温度(T2)が高くなるように設定されている。
このエンジンでは、DPF(7)の再生処理の場合には、DPF(7)の入口側排気温度(T2)が高くなるため、DPF(7)の再生を確実に行うことができる。
Differences between DPF (7) regeneration and catalytic function recovery In the case of the DPF (7) regeneration treatment shown in FIG. 2, the catalytic function recovery treatment of the valve upstream DOC (17) shown in FIG. 3 is higher than in the case of the catalytic function recovery treatment. The inlet side exhaust temperature (T2) of the DPF (7) is set to be high.
In this engine, in the case of the regeneration process of the DPF (7), the exhaust temperature (T2) on the inlet side of the DPF (7) becomes high, so that the regeneration of the DPF (7) can be reliably performed.
図2に示すDPF(7)の再生処理の場合には、図3に示す弁上流側DOC(17)の触媒機能回復処理の場合よりも、アフター噴射燃料の噴射量が少なくなるように設定されている。
このエンジンでは、DPF(7)再生処理の場合には、アフター噴射燃料の噴射量が少ないため、その燃焼熱や、その燃焼熱で燃焼される排気管噴射燃料も少なく、多くの排気管噴射燃料が弁下流側DOC(6)をすり抜けて、DPF(7)で燃焼する。このため、DPF(7)の再生を確実に行うことができる。
また、弁上流側DOC(17)の触媒機能回復処理の場合には、アフター噴射燃料が多いため、その燃焼熱で弁上流側DOC(17)に堆積した未燃焼堆積物が気化または焼却される。このため、弁上流側DOC(17)の触媒機能回復を確実に行うことができる。
In the case of the regeneration process of the DPF (7) shown in FIG. 2, the injection amount of the after-injection fuel is set to be smaller than in the case of the catalytic function recovery process of the valve upstream DOC (17) shown in FIG. ing.
In this engine, in the case of DPF (7) regeneration processing, since the injection amount of the after-injection fuel is small, the combustion heat and the exhaust pipe injection fuel burned by the combustion heat are also small, and many exhaust pipe injection fuels. Passes through the valve downstream DOC (6) and burns at the DPF (7). Therefore, the DPF (7) can be reliably regenerated.
Further, in the case of the catalytic function recovery treatment of the valve upstream side DOC (17), since there is a large amount of after-injection fuel, the unburned deposits deposited on the valve upstream side DOC (17) are vaporized or incinerated by the combustion heat. .. Therefore, the catalytic function of the DOC (17) on the upstream side of the valve can be reliably restored.
このエンジンでは、図1に示す電子制御装置(8)によるDPF(7)の再生処理の流れは次の通りである。
図2に示すように、ステップ(S1)では、DPF(7)の再生処理の開始条件が満たされたか否かが判定される。具体的には、DPF(7)のPM堆積量推定値(APM)がDPF(7)の再生処理の開始判定値(RSJ)以上の値になったか否かが判別される。DPF(7)のPM堆積量推定値(APM)は、図1に示すDPF(7)の出入口間の差圧(ΔP)に基づいてPM堆積量推定値演算装置(32)で算出される。PM堆積量推定値演算装置(32)は、電子制御装置(8)の演算部で構成されている。DPF(7)のPM堆積量推定値(APM)は、差圧(ΔP)による算出以外の方法で算出してもよい。
図2に示すように、ステップ(S1)の判定は、肯定されるまで繰り返され、判定が肯定された場合には、ステップ(S2)に進む。
In this engine, the flow of the regeneration process of the DPF (7) by the electronic control device (8) shown in FIG. 1 is as follows.
As shown in FIG. 2, in step (S1), it is determined whether or not the start condition of the regeneration process of the DPF (7) is satisfied. Specifically, it is determined whether or not the estimated PM accumulation amount (APM) of the DPF (7) becomes a value equal to or higher than the start determination value (RSJ) of the regeneration process of the DPF (7). The PM accumulation amount estimation value (APM) of the DPF (7) is calculated by the PM accumulation amount estimation value calculation device (32) based on the differential pressure (ΔP) between the entrance and exit of the DPF (7) shown in FIG. The PM deposit amount estimation value calculation device (32) is composed of a calculation unit of the electronic control device (8). The PM accumulation amount estimated value (APM) of the DPF (7) may be calculated by a method other than the calculation by the differential pressure (ΔP).
As shown in FIG. 2, the determination in step (S1) is repeated until the determination is affirmed, and if the determination is affirmed, the process proceeds to step (S2).
図2に示すように、ステップ(S2)では、吸気絞り弁(11)の開度減少制御と、排気絞り弁(5)の開度減少制御が行われ、ステップ(S3)に進む。
ステップ(S2)の吸気絞り弁(11)や排気絞り弁(5)の開度減少制御は、吸気絞り弁(11)を駆動するアクチュエータ(11a)と、排気絞り弁(5)を駆動するアクチュエータ(5a)を電子制御装置(8)が制御することにより行われる。
As shown in FIG. 2, in step (S2), the opening degree reduction control of the intake throttle valve (11) and the opening degree reduction control of the exhaust throttle valve (5) are performed, and the process proceeds to step (S3).
The opening reduction control of the intake throttle valve (11) and the exhaust throttle valve (5) in the step (S2) is performed by the actuator (11a) for driving the intake throttle valve (11) and the actuator for driving the exhaust throttle valve (5). (5a) is controlled by the electronic control device (8).
図2に示すように、ステップ(S3)では、弁上流側排気圧(P0)が圧力上限値(Pmax)以下か否かが判定され、判定が肯定された場合には、ステップ(S4-1)に進む。
ステップ(S4-1)では、弁上流側排気温度(T0)がアフター噴射許可温度(TA)以上か否かが判定され、判定が肯定された場合には、ステップ(S5)に進む。
ステップ(S5)では、アフター噴射制御が開始され、ステップ(S6)に進む。
尚、ステップ(S3)での判定が否定された場合には、ステップ(S4-2)に進み、排気絞り弁(5)の開度増加制御がなされ、ステップ(S4-1)に進む。
ステップ(S4-2)の排気絞り弁(5)の開度増加制御は、排気絞り弁(5)を駆動するアクチュエータ(5a)を電子制御装置(8)が制御することにより行われる。
ステップ(S4-1)での判定が否定された場合にはステップ(S3)に戻る。
As shown in FIG. 2, in step (S3), it is determined whether or not the valve upstream exhaust pressure (P0) is equal to or less than the pressure upper limit value (Pmax), and if the determination is affirmative, step (S4-1). ).
In step (S4-1), it is determined whether or not the valve upstream side exhaust temperature (T0) is equal to or higher than the after-injection permitted temperature (TA), and if the determination is affirmed, the process proceeds to step (S5).
In step (S5), after injection control is started, and the process proceeds to step (S6).
If the determination in step (S3) is denied, the process proceeds to step (S4-2), the opening degree increase control of the exhaust throttle valve (5) is performed, and the process proceeds to step (S4-1).
The opening degree increase control of the exhaust throttle valve (5) in the step (S4-2) is performed by controlling the actuator (5a) for driving the exhaust throttle valve (5) by the electronic control device (8).
If the determination in step (S4-1) is denied, the process returns to step (S3).
ステップ(S6)では、弁上流側排気温度(T0)が排気管噴射許可温度(TP)以上か否かが判定される。ステップ(S6)の判定は肯定されるまで繰り返され、判定が肯定されるとステップ(S7)に進む。
ステップ(S7)では、排気管噴射制御が開始され、ステップ(S8)に進む。
In step (S6), it is determined whether or not the valve upstream side exhaust temperature (T0) is equal to or higher than the exhaust pipe injection permitted temperature (TP). The determination in step (S6) is repeated until the determination is affirmed, and when the determination is affirmed, the process proceeds to step (S7).
In step (S7), exhaust pipe injection control is started, and the process proceeds to step (S8).
ステップ(S8)では、DPF(7)の再生処理の終了条件が満たされたか否かが判定される。具体的には、DPF(7)のPM堆積量推定値(APM)がDPF(7)の再生処理の終了判定値(REJ)以下の値になることが終了条件とされ、ステップ(S8)では、この終了条件が肯定されたか否かが判定される。
ステップ(S8)の判定は、肯定されるまで繰り返され、判定が肯定された場合には、ステップ(S9)に進む。
ステップ(S9)では、排気管噴射制御が終了されると共に、暖気管噴射制御も終了され、ステップ(S10)に進む。
ステップ(S10)では、吸気絞り弁(11)が全開にリセットされると共に、排気絞り弁(5)も全開にリセットされ、ステップ(S1)に戻る。
In step (S8), it is determined whether or not the end condition of the regeneration process of the DPF (7) is satisfied. Specifically, the end condition is that the estimated PM accumulation amount (APM) of the DPF (7) is equal to or less than the end determination value (REJ) of the regeneration process of the DPF (7), and in step (S8). , It is determined whether or not this termination condition is affirmed.
The determination in step (S8) is repeated until the determination is affirmed, and if the determination is affirmed, the process proceeds to step (S9).
In step (S9), the exhaust pipe injection control is terminated, the warm air pipe injection control is also terminated, and the process proceeds to step (S10).
In step (S10), the intake throttle valve (11) is reset to fully open, and the exhaust throttle valve (5) is also reset to fully open, returning to step (S1).
尚、ステップ(S8)のDPF(7)のPM堆積量推定値(APM)は、DPF(7)の出入口間の差圧(ΔP)に基づいてPM堆積量推定値演算装置(32)で算出される。
ステップ(S8)のDPF(7)の再生処理の終了条件は、図1に示すDPF(7)の入口側排気温度(T2)が所定のDPF(7)再生処理温度以上の値を所定時間維持したこととしてもよい。
The PM accumulated amount estimated value (APM) of the DPF (7) in step (S8) is calculated by the PM accumulated amount estimated value calculation device (32) based on the differential pressure (ΔP) between the entrance and exit of the DPF (7). Will be done.
The end condition of the regeneration process of the DPF (7) in the step (S8) is that the inlet side exhaust temperature (T2) of the DPF (7) shown in FIG. 1 maintains a value equal to or higher than the predetermined DPF (7) regeneration process temperature for a predetermined time. It may be done.
このエンジンでは、図1に示す電子制御装置(8)による弁下流側DOC(6)または弁上流側DOC(17)の触媒機能回復処理の流れは次の通りである。
図3に示すように、ステップ(S11)では、弁上流側排気温度(T0)が無負荷及び軽負荷運転の判定温度(LJ)以下の値になったか否かが判定される。ステップ(S11)の判定は、肯定されるまで繰り返され、判定が肯定されるとステップ(S12)に進む。
ステップ(S11)では、弁下流側DOC(6)の入口側排気温度(T1)が無負荷又は軽負荷運転の判定温度(LJ)以下の値になったか否かを判定するようにしてもよい。
ステップ(S12)では、無負荷及び軽負荷運転時間を積算し、ステップ(S13)に進む。
ステップ(S13)では触媒機能回復処理の開始条件が満たされたか否かが判定される。具体的には、無負荷及び軽負荷の運転時間の積算値(tL)が触媒機能回復処理の開始判定値(ISJ)以上の値になったか否かが判定され、判定が肯定された場合にはステップ(S14)に進む。ステップ(S13)で判定が否定された場合には、ステップ(S11)に戻る。
In this engine, the flow of the catalytic function recovery processing of the valve downstream side DOC (6) or the valve upstream side DOC (17) by the electronic control device (8) shown in FIG. 1 is as follows.
As shown in FIG. 3, in step (S11), it is determined whether or not the valve upstream side exhaust temperature (T0) has become a value equal to or lower than the determination temperature (LJ) for no-load and light-load operation. The determination in step (S11) is repeated until the determination is affirmed, and when the determination is affirmed, the process proceeds to step (S12).
In step (S11), it may be determined whether or not the inlet side exhaust temperature (T1) of the valve downstream side DOC (6) becomes a value equal to or lower than the determination temperature (LJ) for no-load or light-load operation. ..
In step (S12), the no-load and light-load operation times are integrated, and the process proceeds to step (S13).
In step (S13), it is determined whether or not the start condition of the catalytic function recovery process is satisfied. Specifically, when it is determined whether or not the integrated value (tL) of the operation time of no load and light load is equal to or higher than the start determination value (ISJ) of the catalytic function recovery process, and the determination is affirmed. Proceeds to step (S14). If the determination is denied in step (S13), the process returns to step (S11).
ステップ(S14)では、ステップ(S12)で積算した無負荷及び軽負荷の運転時間の積算値(tL)を0にリセットし、事後に行われる触媒機能回復処理時間の積算を開始し、ステップ(S15)に進む。
ステップ(S15)では、吸気絞り弁(11)の開度減少制御と、排気絞り弁(5)の開度減少制御が行われ、ステップ(S16)に進む。
ステップ(S15)の吸気絞り弁(11)や排気絞り弁(5)の開度減少制御は、前記ステップ(S2)の場合と同様にして行われる。
In step (S14), the integrated value (tL) of the operation time of no load and light load integrated in step (S12) is reset to 0, the integration of the catalytic function recovery processing time performed after the fact is started, and the integration of the catalytic function recovery processing time performed after the fact is started. Proceed to S15).
In step (S15), the opening degree reduction control of the intake throttle valve (11) and the opening degree reduction control of the exhaust throttle valve (5) are performed, and the process proceeds to step (S16).
The opening degree reduction control of the intake throttle valve (11) and the exhaust throttle valve (5) in the step (S15) is performed in the same manner as in the case of the step (S2).
ステップ(S16)では、弁上流側排気圧(P0)が圧力上限値(Pmax)以下か否かが判定され、判定が肯定された場合には、ステップ(S17-1)に進む。
ステップ(S17-1)では、弁上流側排気温度(T0)がアフター噴射許可温度(TA)以上か否かが判定され、判定が肯定された場合には、ステップ(S18)に進む。
ステップ(S18)では、アフター噴射制御が開始され、ステップ(S19)に進む。
ステップ(S16)での判定が否定された場合には、ステップ(S17-2)に進み、排気絞り弁(5)の開度増加制御がなされ、ステップ(S17-1)に進む。
ステップ(S17-1)での排気絞り弁(5)の開度減少制御は、前記ステップ(S4-2)の場合と同様にして行われる。
ステップ(S17-1)での判定が否定された場合にはステップ(S16)に戻る。
In step (S16), it is determined whether or not the valve upstream exhaust pressure (P0) is equal to or less than the pressure upper limit value (Pmax), and if the determination is affirmative, the process proceeds to step (S17-1).
In step (S17-1), it is determined whether or not the valve upstream side exhaust temperature (T0) is equal to or higher than the after injection permitted temperature (TA), and if the determination is affirmed, the process proceeds to step (S18).
In step (S18), after injection control is started, and the process proceeds to step (S19).
If the determination in step (S16) is denied, the process proceeds to step (S17-2), the opening degree increase control of the exhaust throttle valve (5) is performed, and the process proceeds to step (S17-1).
The opening degree reduction control of the exhaust throttle valve (5) in the step (S17-1) is performed in the same manner as in the case of the step (S4-2).
If the determination in step (S17-1) is denied, the process returns to step (S16).
ステップ(S19)では、触媒機能回復処理の終了条件が満たされたか否かが判定される。具体的には、触媒機能回復処理時間の積算値(tI)が触媒機能回復処理の終了判定値(IEJ)以上の値になることが終了条件とされ、ステップ(S19)では、この終了条件が満たされたか否かが判定される。
ステップ(S19)の判定は、肯定されるまで繰り返され、判定が肯定された場合には、ステップ(S20)に進む。
ステップ(S20)では、アフター噴射制御が終了され、ステップ(S21)に進む。
ステップ(S21)では、吸気絞り弁(11)が全開にリセットされると共に、排気絞り弁(5)も全開にリセットされ、ステップ(S14)下段の触媒機能回復処理時間の積算の積算値(tI)を0にリセットし、ステップ(S11)に戻る。なお、ステップ(S14)上段の無負荷及び軽負荷の運転時間の積算値(tL)の0へのリセットも、ステップ(S14)ではなく、ステップ(S21)で行ってもよい。
In step (S19), it is determined whether or not the termination condition of the catalytic function recovery process is satisfied. Specifically, it is a termination condition that the integrated value (tI) of the catalytic function recovery processing time becomes a value equal to or higher than the end determination value (IEJ) of the catalytic function recovery processing, and in step (S19), this termination condition is set. Whether or not it is satisfied is determined.
The determination in step (S19) is repeated until the determination is affirmed, and if the determination is affirmed, the process proceeds to step (S20).
In step (S20), after injection control is terminated, and the process proceeds to step (S21).
In the step (S21), the intake throttle valve (11) is reset to the fully open position, and the exhaust throttle valve (5) is also reset to the fully open position. ) Is reset to 0, and the process returns to step (S11). It should be noted that the integrated value (tL) of the operation time of no load and light load in the upper stage of step (S14) may be reset to 0 in step (S21) instead of step (S14).
図2,3に示す各処理は、それぞれ単独に実行され、それどれ同時に実行されない。いずれかの処理が開始された場合、その処理が終了するまでは、それ以外の処理は開始されない。また、図3の弁下流側DOC(6)の触媒機能回復処理と、弁上流側DOC(17)の触媒機能回復処理は、1回ずつ交互に行ってもよいし、前者1回と後者複数回(例えば、2回または3回)を交互に行ってもよいし、前者複数回(例えば、2回または3回)と後者1回を交互に行ってもよい。 Each of the processes shown in FIGS. 2 and 3 is executed independently, and none of them are executed at the same time. If any of the processes is started, the other processes are not started until the process is completed. Further, the catalytic function recovery treatment of the valve downstream side DOC (6) and the catalytic function recovery treatment of the valve upstream side DOC (17) in FIG. 3 may be alternately performed once, once, and a plurality of the latter. The times (for example, 2 times or 3 times) may be alternately performed, or the former multiple times (for example, 2 times or 3 times) and the latter 1 time may be alternately performed.
なお、上記実施形態の排気絞り弁(5)の上流側排気圧を排気圧センサで実測すると共に、演算でも算出し、その差異に基づいて、排気絞り弁(5)の故障、排気経路(4)からのガス漏れ等の故障診断を行い、或いは、排気絞り弁(5)をDPF(7)の排気下流側に配置し、或いは、弁下流側DOC(6)を省略し、噴射管インジェクタはDOC機能付きのDPF(7)の排気入口側に配置するといった、実施形態の変形を行うこともできる。弁下流側DOC(6)を省略する場合には、弁下流側DOC(6)の入口側排気温度(T1)に代えてDOC機能付きのDPF(7)の入口側排気温度(T2)を用いる。 The upstream exhaust pressure of the exhaust throttle valve (5) of the above embodiment is actually measured by the exhaust pressure sensor and calculated by calculation, and based on the difference, the exhaust throttle valve (5) fails and the exhaust path (4). ), Or the exhaust throttle valve (5) is placed on the exhaust downstream side of the DPF (7), or the valve downstream side DOC (6) is omitted, and the injection pipe injector is It is also possible to modify the embodiment, such as arranging it on the exhaust inlet side of the DPF (7) having a DOC function. When the valve downstream side DOC (6) is omitted, the inlet side exhaust temperature (T2) of the DPF (7) with the DOC function is used instead of the inlet side exhaust temperature (T1) of the valve downstream side DOC (6). ..
(1)…燃焼室、(2)…燃料、(3)…燃料噴射装置、(3a)…排気管インジェクタ、(4)…排気管、(5)…排気絞り弁、(6)…弁下流側DOC、(7)…DPF、(8)…電子制御装置、(9)…排気、(10)…吸気経路、(11)…吸気絞り弁、(12)…弁上流側排気圧の演算装置、(13)…差圧センサ、(14)…大気圧センサ、(15)…排気流量の演算装置、(16)…吸気流量センサ、(17)…弁上流側DOC、(18)…運転時間積算装置、(19)…弁上流側排気温度センサ、(20)…吸気、(S1)…DPFの再生処理の開始条件、(S2)…排気絞り弁の開度減少制御、(S4-2)…排気絞り弁の開度増加制御、(S5)…アフター噴射制御が開始、(S7)…排気噴射制御が開始、(S20)…排気管噴射制御が開始、(T0)…弁上流側排気温度、(TA)…アフター噴射許可温度、(TP)…排気管噴射許可温度、(P0)…弁上流側排気圧、(Pmax)…圧力上限値、(G)…排気の質量流量、(P1)…弁下流側排気圧、(ΔP)…差圧、(P3)…大気圧。 (1) ... Combustion chamber, (2) ... Fuel, (3) ... Fuel injection device, (3a) ... Exhaust pipe injector, (4) ... Exhaust pipe, (5) ... Exhaust throttle valve, (6) ... Valve downstream Side DOC, (7) ... DPF, (8) ... Electronic control device, (9) ... Exhaust, (10) ... Intake path, (11) ... Intake throttle valve, (12) ... Valve upstream side exhaust pressure calculation device , (13) ... differential pressure sensor, (14) ... atmospheric pressure sensor, (15) ... exhaust flow rate calculator, (16) ... intake flow rate sensor, (17) ... valve upstream side DOC, (18) ... operation time Integrator, (19) ... Valve upstream exhaust temperature sensor, (20) ... Intake, (S1) ... DPF regeneration processing start condition, (S2) ... Exhaust throttle valve opening reduction control, (S4-2) ... Exhaust throttle valve opening increase control, (S5) ... After injection control started, (S7) ... Exhaust injection control started, (S20) ... Exhaust pipe injection control started, (T0) ... Valve upstream side exhaust temperature , (TA) ... After injection permitted temperature, (TP) ... Exhaust pipe injection permitted temperature, (P0) ... Valve upstream side exhaust pressure, (Pmax) ... Pressure upper limit value, (G) ... Exhaust mass flow rate, (P1) ... Exhaust pressure on the downstream side of the valve, (ΔP) ... Differential pressure, (P3) ... Atmospheric pressure.
Claims (14)
DPF(7)の再生処理がなされるように構成され、
DPF(7)の再生処理では、PMが堆積したDPF(7)の再生処理の開始条件(S1)が成立した後に排気絞り弁(5)の開度減少制御(S2)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後に燃料噴射装置(3)のアフター噴射制御が開始(S5)され、アフター噴射燃料の燃焼で排気(9)が所定の排気管噴射許可温度(TP)以上の温度になった後に排気管噴射制御が開始(S7)され排気管インジェクタ(3a)から排気管(4)内に噴射された排気管噴射燃料の弁下流側DOC(6)での触媒燃焼で昇温した排気(9)で、DPF(7)に堆積したPMが焼却されるように構成されている、ことを特徴とするディーゼルエンジン。 A fuel injection device (3) that injects fuel (2) into the combustion chamber (1) and an exhaust pipe injector (3a) that injects fuel (2) into the exhaust pipe (4) on the exhaust downstream side of the combustion chamber (1). ), The exhaust throttle valve (5) arranged in the exhaust pipe (4), the valve downstream side DOC (6) arranged on the exhaust downstream side thereof, and the DPF (7) arranged on the exhaust downstream side thereof. And an electronic control device (8) that controls the opening degree of the exhaust throttle valve (5) and the fuel injection of the fuel injection device (3) and the exhaust pipe injector (3a).
It is configured so that the DPF (7) regeneration process is performed.
In the regeneration process of the DPF (7), the opening degree reduction control (S2) of the exhaust throttle valve (5) is performed after the start condition (S1) of the regeneration process of the DPF (7) in which PM is deposited is satisfied, and the exhaust gas (9) is exhausted (9). ) Is at a temperature equal to or higher than the predetermined after-injection permitted temperature (TA), the after-injection control of the fuel injection device (3) is started (S5), and the exhaust (9) is exhausted by the combustion of the after-injection fuel. Exhaust pipe injection control is started (S7) after the temperature reaches the injection permitted temperature (TP) or higher, and the DOC (DOC) on the downstream side of the valve of the exhaust pipe injection fuel injected from the exhaust pipe injector (3a) into the exhaust pipe (4). A diesel engine characterized in that the PM deposited in the DPF (7) is incinerated by the exhaust gas (9) whose temperature has been raised by the catalytic combustion in 6).
吸気経路(10)に配置された吸気絞り弁(11)を備え、その開度が電子制御装置(8)で制御されるように構成され、
DPF(7)の再生処理では、DPF(7)の再生処理の開始条件(S1)が成立した後に排気絞り弁(5)の開度減少制御(S2)がなされると共に、吸気絞り弁(11)の開度減少制御(S2)がなされるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 1,
The intake throttle valve (11) arranged in the intake path (10) is provided, and the opening degree thereof is configured to be controlled by the electronic control device (8).
In the regeneration process of the DPF (7), after the start condition (S1) of the regeneration process of the DPF (7) is satisfied, the opening reduction control (S2) of the exhaust throttle valve (5) is performed, and the intake throttle valve (11) is performed. ) Is configured to be controlled to reduce the opening degree (S2).
DPF(7)の再生処理では、排気絞り弁(5)の開度減少制御(S2)がなされ、弁上流側排気圧(P0)が所定の圧力上限値(Pmax)を超えた場合には、その後に排気絞り弁(5)の開度増加制御(S4-2)がなされるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 1 or 2.
In the regeneration process of the DPF (7), the opening degree reduction control (S2) of the exhaust throttle valve (5) is performed, and when the valve upstream exhaust pressure (P0) exceeds a predetermined pressure upper limit value (Pmax), A diesel engine characterized in that the opening degree increase control (S4-2) of the exhaust throttle valve (5) is subsequently performed.
弁上流側排気圧(P0)の演算装置(12)を備え、弁上流側排気圧(P0)は、排気(9)の質量流量(G)と、弁上流側排気温度(T0)と、弁下流側排気圧(P1)から演算で算出されるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 3,
A calculation device (12) for the valve upstream side exhaust pressure (P0) is provided, and the valve upstream side exhaust pressure (P0) includes the mass flow rate (G) of the exhaust (9), the valve upstream side exhaust temperature (T0), and the valve. A diesel engine characterized in that it is configured to be calculated from the downstream exhaust pressure (P1).
DPF(7)の出入口間の差圧(ΔP)を検出する差圧センサ(13)と、大気圧(P3)を検出する大気圧センサ(14)を備え、
弁下流側排気圧(P1)は、DPF(7)の出入口間の差圧(ΔP)と大気圧(P3)から演算で算出されるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 4,
A differential pressure sensor (13) for detecting the differential pressure (ΔP) between the entrance and exit of the DPF (7) and an atmospheric pressure sensor (14) for detecting the atmospheric pressure (P3) are provided.
A diesel engine characterized in that the valve downstream exhaust pressure (P1) is configured to be calculated from the differential pressure (ΔP) between the entrance and exit of the DPF (7) and the atmospheric pressure (P3).
弁上流側排気温度センサ(19)を備え、これで検出される弁上流側排気温度(T0)が、弁上流側排気圧(P0)の演算に用いられていると共に、アフター噴射許可温度(TA)及び排気管噴射許可温度(TP)との温度比較判定に用いられている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 4 or 5.
A valve upstream side exhaust temperature sensor (19) is provided, and the valve upstream side exhaust temperature (T0) detected by the valve upstream side exhaust temperature sensor (19) is used in the calculation of the valve upstream side exhaust pressure (P0), and the after injection allowable temperature (TA) is used. ) And the diesel engine used for the temperature comparison determination with the exhaust pipe injection permitted temperature (TP).
排気絞り弁(5)の排気上流側に配置される弁上流側DOC(17)を備えている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to any one of claims 1 to 6.
A diesel engine characterized by having a valve upstream side DOC (17) arranged on the exhaust upstream side of the exhaust throttle valve (5).
弁上流側DOC(17)と弁下流側DOC(6)には、セル内を排気(9)が通過するハニカム担体に触媒成分を担持させたフロースルー型の酸化触媒が用いられている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 7.
A flow-through type oxidation catalyst in which a catalyst component is supported on a honeycomb carrier through which the exhaust (9) passes through the cell is used for the valve upstream side DOC (17) and the valve downstream side DOC (6). Diesel engine featuring.
弁下流側DOC(6)の触媒機能回復処理がなされるように構成され、
弁下流側DOC(6)の触媒機能回復処理では、未燃燃料やPMからなる未燃焼堆積物の堆積に基づいて機能低下した弁下流側DOC(6)の触媒機能回復処理の開始条件(S13)が成立した後に排気絞り弁(5)の開度減少制御(S15)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後にアフター噴射制御が開始(S18)され、アフター噴射燃料の燃焼で昇温した排気(9)で、弁下流側DOC(6)に堆積した未燃焼堆積物が気化または焼却されるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to any one of claims 1 to 8.
It is configured so that the catalytic function recovery treatment of the valve downstream DOC (6) is performed.
In the catalytic function recovery treatment of the valve downstream side DOC (6), the start condition (S13) of the catalytic function recovery treatment of the valve downstream side DOC (6) whose function has deteriorated due to the accumulation of unburned deposits consisting of unburned fuel and PM. ) Is satisfied, the opening reduction control (S15) of the exhaust throttle valve (5) is performed, and the after injection control is started after the exhaust (9) reaches a temperature equal to or higher than the predetermined after injection permitted temperature (TA) (S18). ), And the exhaust gas (9) heated by the combustion of the after-injection fuel is configured to vaporize or incinerate the unburned deposits deposited on the DOC (6) on the downstream side of the valve. diesel engine.
無負荷及び/又は軽負荷運転の運転時間を積算する運転時間積算装置(18)を備え、
無負荷及び/又は軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合には、弁下流側DOC(6)の触媒機能回復処理の開始条件(S13)が成立するように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 9,
Equipped with an operation time integration device (18) that integrates the operation time of no-load and / or light-load operation.
When the integrated value (tL) of the operation time of no load and / or light load reaches the predetermined start determination value (ISJ) of the catalytic function recovery process, the catalytic function recovery process of the valve downstream side DOC (6) is performed. A diesel engine characterized in that it is configured so that the start condition (S13) is satisfied.
排気絞り弁(5)の排気上流側に配置された弁上流側DOC(17)を備え、
弁上流側DOC(17)の触媒機能能回復処理がなされるように構成され、
弁上流側DOC(17)の触媒機能回復処理では、未燃燃料やPMからなる未燃焼堆積物の堆積に基づいて機能低下した弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立した後に排気絞り弁(5)の開度減少制御(S15)がなされ、排気(9)が所定のアフター噴射許可温度(TA)以上の温度になった後にアフター噴射制御が開始(S18)され、アフター噴射燃料の燃焼で昇温した排気(9)の熱で、弁上流側DOC(17)に堆積した未燃焼堆積物が気化または焼却されるように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to any one of claims 1 to 8.
It is equipped with a valve upstream side DOC (17) arranged on the exhaust upstream side of the exhaust throttle valve (5).
It is configured so that the catalytic function recovery treatment of the valve upstream DOC (17) is performed.
In the catalytic function recovery treatment of the valve upstream side DOC (17), the start condition (S13) of the catalytic function recovery treatment of the valve upstream side DOC (17) whose function has deteriorated due to the accumulation of unburned deposits consisting of unburned fuel and PM. ) Is satisfied, the opening reduction control (S15) of the exhaust throttle valve (5) is performed, and the after injection control is started after the exhaust (9) reaches a temperature equal to or higher than the predetermined after injection permitted temperature (TA) (S18). ), And the heat of the exhaust (9) raised by the combustion of the after-injection fuel is configured to vaporize or incinerate the unburned deposits deposited on the DOC (17) on the upstream side of the valve. Diesel engine.
無負荷及び/又は軽負荷運転の運転時間を積算する運転時間積算装置(18)を備え、
無負荷及び/又は軽負荷の運転時間の積算値(tL)が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合には、弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立するように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 11,
Equipped with an operation time integration device (18) that integrates the operation time of no-load and / or light-load operation.
When the integrated value (tL) of the operation time of no load and / or light load reaches the predetermined start determination value (ISJ) of the catalytic function recovery process, the catalytic function recovery process of the valve upstream DOC (17) is performed. A diesel engine characterized in that it is configured so that the start condition (S13) is satisfied.
弁上流側排気圧(P0)が所定の触媒機能回復処理の開始判定値に至った場合には、弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立するように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to claim 11 or 12.
When the valve upstream side exhaust pressure (P0) reaches a predetermined catalytic function recovery processing start determination value, the valve upstream side DOC (17) is configured to satisfy the catalytic function recovery processing start condition (S13). A diesel engine that is characterized by being.
DPF(6)の再生処理回数が所定の触媒機能回復処理の開始判定値(ISJ)に至った場合には、弁上流側DOC(17)の触媒機能回復処理の開始条件(S13)が成立するように構成されている、ことを特徴とするディーゼルエンジン。 In the diesel engine according to any one of claims 11 to 13.
When the number of regeneration processes of the DPF (6) reaches a predetermined start determination value (ISJ) of the catalytic function recovery process, the start condition (S13) of the catalytic function recovery process of the valve upstream DOC (17) is satisfied. A diesel engine characterized by being configured in such a way.
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JP2005315189A (en) * | 2004-04-30 | 2005-11-10 | Isuzu Motors Ltd | Exhaust gas aftertreatment device for diesel engine |
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JP2017227182A (en) * | 2016-06-23 | 2017-12-28 | 株式会社クボタ | diesel engine |
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JP2005315189A (en) * | 2004-04-30 | 2005-11-10 | Isuzu Motors Ltd | Exhaust gas aftertreatment device for diesel engine |
JP2006283748A (en) * | 2005-03-07 | 2006-10-19 | Honda Motor Co Ltd | Exhaust emission control device for internal combustion engine |
JP2006316720A (en) * | 2005-05-13 | 2006-11-24 | Toyota Motor Corp | Exhaust emission control system for internal combustion engine |
JP2011256848A (en) * | 2010-06-11 | 2011-12-22 | Isuzu Motors Ltd | Exhaust emission control system |
JP2017227182A (en) * | 2016-06-23 | 2017-12-28 | 株式会社クボタ | diesel engine |
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