JP4760770B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine that uses light and heavy fuels separated from the fuel to improve the purification performance of harmful components in exhaust gas discharged from the internal combustion engine.

Nitrogen oxide (NO _x ) contained in the exhaust gas of a diesel engine absorbs NO _x when the ambient atmosphere has a lean air-fuel ratio, and releases NO _x when the atmosphere is a stoichiometric or rich air-fuel ratio ( NO _x ) A catalyst device carrying a purification catalyst is arranged in the engine exhaust system so that NO _x contained in the exhaust gas of the diesel engine is absorbed by the catalyst for NO _x purification of the catalyst device to suppress atmospheric release. I have to. Further, there is a limit to the absorption capacity of the NO _X which is provided to the catalytic converter, prior to NO _X absorbing capacity of the NO _X purification catalyst of the catalytic converter is saturated, the neighborhood atmosphere rich air-absorbed In addition to releasing NO _x , regeneration processing for reducing and purifying NO _x released by the reducing substance when the rich air-fuel ratio is achieved has been performed.

In general, light oil is used as fuel for diesel engines, high-boiling hydrocarbons contained in the gas oil (HC) has a low selectivity for reducing NO _X, occluded in the NO _X purification catalyst When used as a reducing agent for reducing NO _x , an excessive amount of HC is required, resulting in deterioration of fuel consumption.

  In addition, if high-boiling HC is contained in the exhaust gas of a diesel engine, particulate matter containing carbon as a main component (hereinafter referred to as PM (Particulate Matter)) will increase, and such PM will cause air pollution. Therefore, it is necessary to capture and remove PM in the exhaust gas.

Therefore, as an exhaust gas purification apparatus for an internal combustion engine that conventionally separates into a low boiling point HC and a high boiling point HC and uses the low boiling point HC to improve the NO _x purification performance, for example, an internal combustion engine as shown in FIG. Exhaust gas purification devices have been proposed. FIG. 10 is a diagram showing an example of the configuration of a conventional exhaust emission control device for an internal combustion engine. As shown in FIG. 10, the exhaust purification system of a conventional internal combustion engine, NO _X the neighborhood atmosphere absorbs NO _X when the lean air-fuel ratio and releases NO _X when the theoretical air-fuel ratio (stoichiometric) or rich air-fuel ratio Fuel for separating the catalyst device 101 carrying the purification catalyst, the fuel in the fuel tank 102 into a low carbon component fuel 103 having a small number of carbon atoms and a high carbon component fuel 104 mainly composed of a high carbon component having a large number of carbon atoms. And a separation device 105. The low carbon component fuel 103 is separated from the fuel in the fuel tank 102 by the fuel separator 105 and the low carbon component fuel 103 is supplied to the catalyst device 101 via the supply pipe 106, and the NO _x purification catalyst in the catalyst device 101 is supplied. the occluded NO _X is reduced to, and out the regenerating process of the NO _X purification catalyst. Further, the high carbon component fuel 104 is recovered again in the fuel tank 102 (Patent Documents 1 to 3).

As described above, in the exhaust emission control device of the conventional internal combustion engine, the HC contained in the fuel is decomposed by the fuel separation device 105, and the low carbon component fuel 103 is added as the reducing agent to the upstream side of the catalyst device 101, thereby performs reproduction processing of the NO _X purification catalyst in the apparatus 101, has been to improve the purification performance of the NO _X in the exhaust gas.

JP 2006-170186 A JP 2006-291847 A JP 2006-132396 A

However, in a conventional internal combustion engine exhaust gas purification device, the low carbon component fuel 103 is used as a reducing agent, and the high carbon component fuel 104 is supplied to the fuel tank 102 only for the purpose of regenerating the NO _x purification catalyst. However, since it is only circulated and the disposal destination is not sufficiently considered, there is a problem that the high carbon component fuel 104 is accumulated in the fuel tank 102 at a high concentration.

  Further, when the high carbon component fuel 104 is used as a fuel for combustion of an internal combustion engine, for example, the high carbon component fuel 104 is accumulated at a high concentration in the fuel tank 102. There is a problem that the component fuel 104 is always mixed at the same rate into, for example, light oil, which is a combustion fuel, and cannot be supplied to the internal combustion engine.

  Further, since the concentrated high carbon component fuel 104 is supplied for combustion of the internal combustion engine, an appropriate proportion of the high carbon component fuel 104 permitted by the internal combustion engine cannot be supplied to the internal combustion engine. There is a problem that the combustion efficiency and the exhaust gas composition of the exhaust gas deteriorate.

  Further, when the concentrated high carbon component fuel 104 is mixed with light oil and continuously supplied to the internal combustion engine, the high carbon component fuel 104 exceeds the allowable range of the internal combustion engine, and as a result, the increased high carbon content fuel 104 is obtained. There is a problem that the amount of soot generated due to the carbon component fuel 104 increases.

  Further, PM in the exhaust gas is collected by a PM filter or the like, and the collected PM is periodically forcibly oxidized to regenerate the PM collection function (hereinafter referred to as “PM regeneration”). The PM caused by soot generated mainly from the high carbon component fuel 104 is further increased when the high carbon component fuel 104 is increased, and the amount of PM generated due to the increasing high carbon component fuel 104 is further increased. There is a problem that the PM regeneration frequency increases.

  The present invention has been made in view of the above problems, and separates fuel into light fuel and heavy fuel, and adds them from the exhaust addition valve into the exhaust system and the engine cylinder, thereby purifying exhaust gas. An object of the present invention is to provide an exhaust emission control device for an internal combustion engine that improves the engine.

  In order to achieve the above object, an exhaust gas purification apparatus for an internal combustion engine according to the present invention includes a nitrogen oxide purification catalyst that contains a nitrogen oxide purification catalyst that purifies nitrogen oxide in exhaust gas in an exhaust passage. An internal combustion engine having a device and a particulate matter collecting device provided downstream of the nitrogen oxide purification device and having a filter function for collecting particulate matter in the exhaust gas in the exhaust passage An exhaust emission control device, comprising a fuel separation device that separates fuel into light fuel with a lot of light components and heavy fuel with a lot of heavy components, and using the light fuel as a fuel for engine combustion, PM that uses the light fuel during the reduction of nitrogen oxides stored in the catalyst for purifying nitrogen oxides, and regenerates the PM collection function by burning off the PM collected in the particulate matter collection device The heavy fuel separated during regeneration Which comprises using.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, in the fuel separation apparatus, a first exhaust addition valve that supplies the light fuel separated in the fuel separation apparatus to an upstream side of the nitrogen oxide purification apparatus, and And a second exhaust addition valve for supplying the separated heavy fuel between the nitrogen oxide purification device and the particulate matter collection device.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the interval between the nitrogen oxide purification apparatus and the particulate matter collecting apparatus has a predetermined interval at which temperature transmission is unlikely to occur.

  The exhaust gas purification apparatus for an internal combustion engine according to the present invention includes a heavy fuel storage tank that stores the heavy fuel separated by the fuel separator.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, when PM regeneration is performed in the particulate matter trapping apparatus, an addition amount for adding the light fuel from the first exhaust addition valve, and the exhaust gas Based on the amount of air, the amount of addition of the heavy fuel is adjusted from the second exhaust addition valve.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the number of times of addition of the heavy fuel is adjusted from the second exhaust addition valve in accordance with the bed temperature in the particulate matter trapping device. And

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, an addition start timing at which the addition of the light fuel is started from the first exhaust addition valve, an addition interval at which the light fuel is added again, and an air amount of the exhaust gas Based on the above, the addition start timing for starting the addition of the heavy fuel from the second exhaust addition valve and the addition interval for adding the heavy fuel again are adjusted.

  According to the present invention, the fuel separation device for separating the fuel into the light fuel having a large amount of light components and the heavy fuel having a large amount of heavy components is provided, and the light fuel can always be used as a fuel for in-cylinder combustion. The light fuel is atomized by in-cylinder combustion and gasification is promoted. As a result, fuel that is atomized like light fuel and has high vaporization characteristics can be supplied into the engine cylinder, thereby suppressing the generation of PM derived from components in the fuel generated by engine cylinder combustion. Can do.

  In addition, by suppressing the PM generation and reducing the amount of PM collected in the particulate matter collection device, the period for performing PM regeneration is not used as a fuel for in-cylinder combustion. It can be made longer than when fuel is used. Therefore, deterioration of fuel consumption can be suppressed by suppressing the amount of PM collected in the particulate matter collection device and lengthening the period of PM regeneration.

In addition, since the first exhaust addition valve for supplying the light fuel to the upstream side of the nitrogen oxide purification device is provided, the exhaust gas temperature is reduced by always injecting the light fuel to the upstream side of the nitrogen oxide purification device. Even if it is low, most of the light fuel can be atomized and vaporized, and the HC component can be efficiently used as a reducing agent in the NO _x reduction reaction. Thus, the reduction reaction of the NO _X conducted efficiently, it is possible to increase the NO _X reduction efficiency. As a result, it is possible to improve the NO _X purification performance of the NO _X purification catalyst.

  In addition, since it includes a second exhaust addition valve that supplies heavy fuel between the nitrogen oxide purification device and the particulate matter collection device, the heavy fuel is supplied upstream of the particulate matter collection device. Since it can always inject, the bed temperature in a particulate matter collection device can be raised.

In addition, by ensuring a predetermined interval between the nitrogen oxide purification device and the particulate matter collection device where temperature transfer is unlikely to occur, the particulate oxide collection device can be used even during PM regeneration of the particulate matter collection device. PM regeneration can be performed in the particulate matter collecting apparatus while preventing thermal degradation of the NO _x purification catalyst.

  Moreover, since it has the heavy fuel storage tank which stores the heavy fuel isolate | separated with the fuel separator, a particulate matter collection apparatus can be supplied only when it is required.

  Also, when performing PM regeneration in the particulate matter collection device, based on the value of the amount of light fuel added by the first exhaust addition valve, the number of additions, the addition interval, the amount of air in the exhaust gas, The amount of heavy fuel added from the second exhaust addition valve, the number of additions, the addition start timing, and the addition interval can be adjusted. For this reason, when performing PM regeneration in the particulate matter collection device, the addition ratio of the heavy fuel supplied to the particulate matter collection device from the second exhaust addition valve can be controlled. It is possible to stably perform the bed temperature at a temperature required for PM regeneration while preventing deterioration of the filter function in the collecting device and preventing deterioration of fuel consumption. In addition, it is possible to prevent the discharge of HC and the like in the exhaust gas by stabilizing the bed temperature while preventing the filter function in the particulate matter collecting apparatus from deteriorating.

Therefore, the light and heavy fuels separated from the fuel can be efficiently and effectively treated to prevent the deterioration of combustion efficiency and exhaust gas composition, and the amount of soot generated due to the heavy fuel can be reduced. In addition, it is possible to improve the reduction efficiency of NO _x stored in the NO _x purification catalyst and the PM regeneration efficiency in the particulate matter collection device.

  Hereinafter, an example in which an exhaust emission control device for an internal combustion engine according to the present invention is applied to a diesel engine system will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

FIG. 1 is a schematic configuration diagram showing a diesel engine system to which an exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram schematically showing the configuration of the engine system shown in FIG.
As shown in FIG. 1, an internal combustion engine (hereinafter referred to as an engine) 11 is an in-line four-cylinder diesel engine having a fuel supply system 12, a combustion chamber 13, an intake system 14, an exhaust system 15 and the like as main parts. System.

  The fuel supply system 12 includes a fuel tank 16, a main fuel passage L1, a fuel separator 17, a light fuel feed passage L2, a fuel pump 18, an engine fuel passage L3, a common rail 19, a fuel injection valve 21, a light fuel addition passage L4, The first exhaust addition valve 22-1, the heavy fuel addition passage L5, and the second exhaust addition valve 22-2 are provided.

  The fuel pumped up from the fuel tank 16 via the main fuel passage L1 is supplied to the fuel separator 17. The fuel separator 17 separates the fuel supplied from the fuel tank 16 into a light fuel 23 having a large amount of light components and a heavy fuel 24 having a large amount of heavy components.

  Here, in the present invention, the light fuel is a light fuel that contains many low-boiling components and easily evaporates, and is a fuel containing many components having a low distillation temperature. A heavy fuel is a heavy fuel that contains a large amount of high-boiling components and is difficult to evaporate, and is a fuel that contains many components having a high distillation temperature.

  In the present embodiment, the fuel separation device 17 may be any system that can selectively separate the fuel into the light fuel 23 and the heavy fuel 24. For example, the heating temperature is controlled to control the light fuel 23 and the heavy fuel 23. Although there is a method of fractionating and removing the quality fuel 24, a method using a separation membrane, etc., it is not particularly limited to these.

  The fuel pump 18 increases the pressure of the light fuel 23 pumped from the fuel separator 17 via the light fuel supply passage L2, and supplies it to the common rail 19 via the engine fuel passage L3. The common rail 19 accumulates the high-pressure light fuel 23 supplied from the fuel pump 18 at a predetermined pressure and distributes it to each fuel injection valve 21. A fuel injection valve 21 that is an electromagnetic valve injects fuel into the combustion chamber 13.

  Thereby, since the light fuel 23 can be injected and supplied into the combustion chamber 13 from each fuel injection valve 21, the light fuel 23 can be always used as a fuel for engine cylinder combustion. The light fuel 23 is atomized by combustion in the engine cylinder, and gasification is promoted. Therefore, since the fuel is atomized like the light fuel 23 and has high vaporization characteristics in the engine cylinder, it is possible to suppress the generation of PM derived from the components in the fuel generated by the engine cylinder combustion. be able to. Further, by suppressing the PM generation and reducing the amount of PM collected in the particulate matter collection device 43, the cycle of performing PM regeneration for forcibly oxidizing PM and regenerating the PM collection function is set to the engine cylinder. It can be made longer than the case of using a normal fuel that does not use the light fuel 23 as the internal combustion fuel.

  Therefore, deterioration of fuel consumption can be suppressed by suppressing the amount of PM collected in the particulate matter collection device 43 and lengthening the period of PM regeneration.

  The intake system 14 forms a passage (intake passage) for intake air supplied into each combustion chamber 13. The exhaust system 15 forms a passage (exhaust passage) for exhaust gas discharged from each combustion chamber 13.

  Further, the engine 11 includes a turbocharger 32 that supercharges the intake air 31 by the exhaust gas. The intercooler 33 provided in the turbocharger 32 forcibly cools the intake air whose temperature has been increased by supercharging. The throttle valve 34 provided downstream of the intercooler 33 is a so-called electronic throttle, and adjusts the supply amount of intake air.

  Further, the engine 11 is provided with an EGR passage 35 that bypasses the intake system 14 and the exhaust system 15 and returns a part of the exhaust to the intake system 14. The EGR passage 35 is provided with an EGR valve 36 for adjusting the exhaust gas flow rate and an EGR cooler 37 for cooling the exhaust gas.

The exhaust system 15 includes a nitrogen oxides (NO _X) nitrogen oxides for purifying (NO _X) nitrogen oxide purification catalyst is contained purifier 42 in the exhaust gas on the main exhaust passage 41, A particulate matter collecting device 43 provided with a PM filter for collecting particulate matter (PM) in the exhaust gas is disposed on the downstream side.

NO _X purifying catalyst contained in the nitrogen oxide purification device 42, exhaust gas air-fuel ratio occludes NO _X in the exhaust gas when the lean exhaust air-fuel ratio in the exhaust gas is added at the time of the rich that HC, is to reducing and releasing occluded NO _X by CO or the like.

As NO _X purification catalyst, _{specifically,} NSR (NO X Storage Reduction) and _{DPNR (Diesel Particulate-NO X Reduction} System) is known. NSR is a NO _X storage reduction catalyst that stores NO _X in the form of nitrate in the catalyst during operation in the lean operation mode and reduces the nitrate to N ₂ in a reducing atmosphere with a reduced oxygen concentration. is there. Further, the DPNR, is that of a system capable to purify continuously particulate matter (PM) and NO _X at the same time, for example, NO _X occluded in the DPF is PM trapping device (Diesel Particulate Filter) A reduction catalyst is supported. In this embodiment, a NO _x storage reduction catalyst (NSR) is applied as the NO _x purification catalyst.

  Moreover, the particulate matter collection device 43 includes a PM filter that collects PM in the exhaust gas. As the particulate matter collection device 43, for example, there is a DPF (Diesel Particulate Filter).

Here, the particulate matter collection device 43 is disposed downstream of the nitrogen oxide purification device 42 in the exhaust gas flow direction, and NO _X is occluded in the NO _x purification catalyst in the nitrogen oxide purification device 42. The PM in the exhaust gas is collected by the PM filter in the particulate matter collecting device 43 and exhausted.

As for whether the PM filter nitrogen oxide purifier NO _X purification catalyst and the particulate matter trapping device 43 in 42 is active, the respective catalyst bed temperature, detects the filter bed temperature You may judge by doing.

  In addition, a first exhaust addition valve 22-1 for supplying the light fuel 23 to the upstream side of the nitrogen oxide purification device 42 is provided. The fuel separator 17 supplies a part of the light fuel 23 to the first exhaust addition valve 22-1 via the light fuel addition passage L4. During this supply, the first exhaust addition valve 22-1 is opened and the light fuel 23 is injected. In addition, it is closed when not necessary, and the supply of the light fuel 23 is stopped.

By always injecting the light fuel 23 from the first exhaust addition valve 22-1 to the upstream side of the nitrogen oxide purifying device 42, even when the exhaust gas temperature is low, most of the light fuel 23 is atomized and vaporized. _The HC component can be efficiently used as a reducing agent in the reduction reaction of _X. As a result, the reduction reaction of NO _x stored in the NO _x purification catalyst in the nitrogen oxide purification device 42 can be performed efficiently, and the reduction efficiency of NO _x can be increased. As a result, it is possible to improve the NO _X purification performance of the NO _X purification catalyst.

Further, the light fuel 23 from the first exhaust addition valve 22-1 is supplied to the nitrogen oxide purification device 42, the temperature at which thermal degradation of the NO _X catalyst for purifying nitrogen oxide purification device 42 does not occur (for example 400 ° C. ) by heating to a degree, while suppressing the thermal deterioration of the NO _X purification catalyst, it is possible to increase the filter bed temperature of the PM filter of the particulate matter trapping device 43.

  Moreover, it has the 2nd exhaust gas addition valve 22-2 which supplies the heavy fuel 24 between the nitrogen oxide purification apparatus 42 and the particulate matter collection apparatus 43. FIG. The fuel separator 17 supplies the heavy fuel 24 to the second exhaust addition valve 22-2 via the heavy fuel addition passage L5, and supplies the heavy fuel 24 to the particulate matter collection device 43.

  As a result, since the heavy fuel 24 can be constantly injected between the nitrogen oxide purification device 42 and the particulate matter collection device 43 from the second exhaust addition valve 22-2, the particulate matter collection device. The filter bed temperature of the PM filter in 43 can be raised.

  Further, by supplying the heavy fuel 24 to the particulate matter collecting device 43 in which the light fuel 23 is supplied and the filter bed temperature is raised, the filter bed temperature in the particulate matter collecting device 43 is further raised. be able to.

  Therefore, the PM filter in the particulate matter collection device 43 is efficiently raised to the filter bed temperature (for example, 550 ° C.) necessary for PM regeneration, and the PM in the particulate matter collection device 43 is forcibly oxidized to PM. Playback can be performed.

Further, the particulate matter capturing apparatus 43 for the high temperature, heat is transferred in the NO _X catalyst for purifying nitrogen oxide purification device 42, there is a risk of thermal degradation. For this reason, the space | interval of the nitrogen oxide purification apparatus 42 and the particulate matter collection device 43 ensures the predetermined space | interval with which the nitrogen oxide purification device 42 and the particulate matter collection device 43 hardly transmit temperature.

As a result, by ensuring a gap, even when the PM regeneration of the particulate matter trapping device 43, while preventing the thermal deterioration of the NO _X catalyst for purifying nitrogen oxide purification device 42, particulate matter The PM regeneration efficiency of the PM filter of the collection device 43 can be increased.

  A metering valve (not shown) is also provided in the light fuel addition passage L4 and the heavy fuel addition passage L5. This metering valve controls the pressure (fuel pressure) of the fuel supplied to the first exhaust addition valve 22-1 and the second exhaust addition valve 22-2. The first exhaust addition valve 22-1 and the second exhaust addition valve 22-2, which are solenoid valves, are a nitrogen oxide purifying device for the exhaust system 15 with appropriate amounts and timing of light fuel 23 and heavy fuel 24. 42 is added to the upstream side of 42 and the upstream side of the particulate matter collecting device 43.

Each part of the engine 11 is provided with an air flow meter 44 that detects the intake air amount and a temperature sensor 45 that detects the filter bed temperature of the PM filter in the particulate matter collection device 43. Further, on the downstream side of the nitrogen oxide purifying device 42 and the downstream side of the particulate matter collecting device 43, air-fuel ratio sensors 46-1 and 46-2 for detecting the oxygen concentration in the exhaust gas, and particulate matter trapping. A NO _x sensor 47 for detecting the nitrogen concentration downstream of the collecting device 43 is provided. Further, exhaust temperature sensors 48-1 and 48-2 for measuring the gas temperature of the exhaust gas are provided on the downstream side of the nitrogen oxide purification device 42 and the downstream side of the particulate matter collection device 43.

  Further, in the present embodiment, the first exhaust addition valve 22-1 and the second exhaust addition valve 22-2 are particularly capable of pulverizing and ejecting the light fuel 23 or the heavy fuel 24, respectively. It is not limited to this.

  Although not shown, each part of the engine 11 includes an air flow meter 44 that detects the intake air amount, a temperature sensor and a pressure sensor that detect the temperature and pressure of the fuel in the common rail 19, and a crankshaft rotation of the engine 11. Crank position sensor to detect, intake air temperature sensor to detect intake air temperature, intake air pressure sensor to detect intake air pressure, accelerator opening sensor to detect accelerator pedal depression amount (accelerator opening), and opening of throttle valve 34 A throttle position sensor for detecting the coolant temperature of the engine 11 and a water temperature sensor for detecting the coolant temperature of the engine 11 are provided.

  An electronic control unit (ECU) (not shown) inputs detection signals from the various sensors such as the air-fuel ratio sensors 46-1, 46-2 and the exhaust temperature sensors 48-1, 48-2 via an external input circuit. On the basis of this signal, the opening / closing control of the fuel injection valve 21, the first exhaust addition valve 22-1 and the second exhaust addition valve 22-2 is performed, and the light fuel 23 ejected from the first exhaust addition valve 22-1 is controlled. Various controls relating to the operating state of the engine 11 such as adjustment of the addition amount and the addition amount of the heavy fuel 24 ejected from the second exhaust addition valve 22-2 are performed.

  Thus, according to the diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to this embodiment is applied, the fuel separation device 17 that separates the fuel into the light fuel 23 and the heavy fuel 24 is provided, and the light fuel 23 Can be injected into the combustion chamber 13 so that the light fuel 23 can always be used as a fuel for in-cylinder combustion. The light fuel 23 is atomized by in-cylinder combustion and gasification is promoted. The Therefore, since the fuel is atomized like the light fuel 23 and has high vaporization characteristics in the engine cylinder, it is possible to suppress the generation of PM derived from the components in the fuel generated by the engine cylinder combustion. be able to. Further, by suppressing the PM generation and reducing the amount of PM collected in the particulate matter collection device 43, the light regeneration cycle is not used as the fuel for in-cylinder combustion in the PM regeneration period. It can be made longer than the case of using normal fuel. Therefore, deterioration of fuel consumption can be suppressed by suppressing the amount of PM collected in the particulate matter collection device 43 and lengthening the period of PM regeneration.

Further, since the first exhaust addition valve 22-1 for supplying the light fuel 23 to the upstream side of the nitrogen oxide purification device 42 is provided, the light fuel 23 is supplied from the first exhaust addition valve 22-1 to the nitrogen oxide. It can always be supplied to the purifier 42. For this reason, even when the exhaust gas temperature is low, most of the light fuel 23 is atomized and vaporized, and the HC component can be efficiently used as a reducing agent in the NO _x reduction reaction. As a result, the reduction reaction of NO _x stored in the NO _x purification catalyst in the nitrogen oxide purification device 42 can be performed efficiently, and the reduction efficiency of NO _x can be increased. As a result, it is possible to improve the NO _X purification performance of the NO _X purification catalyst.

Further, the nitrogen oxide purification device 42 a light fuel 23 from the first exhaust addition valve 22-1, temperature (e.g., 400 ° C.) thermal degradation of the NO _X catalyst for purifying nitrogen oxide purification device 42 does not occur much By heating up to this point, the filter bed temperature of the PM filter in the particulate matter collecting device 43 can be increased while suppressing thermal degradation of the NO _x purification catalyst.

  Further, since the second exhaust addition valve 22-2 for supplying the heavy fuel 24 between the nitrogen oxide purification device 42 and the particulate matter collection device 43 is provided, the second exhaust addition valve 22- 2, the heavy fuel 24 can be constantly injected between the nitrogen oxide purification device 42 and the particulate matter collection device 43, and the filter bed temperature of the PM filter in the particulate matter collection device 43 is increased. be able to. Therefore, the PM filter in the particulate matter collection device 43 is efficiently raised to the filter bed temperature (for example, 550 ° C.) necessary for PM regeneration, and the PM in the particulate matter collection device 43 is forcibly oxidized to PM. Playback can be performed.

Further, by ensuring a predetermined interval between the nitrogen oxide purification device 42 and the particulate matter collecting device 43 where temperature transfer is unlikely to occur, the nitrogen oxide purification device 42 can also purify the nitrogen oxide during PM regeneration of the particulate matter collection device 43. The PM regeneration of the PM filter of the particulate matter collecting device 43 can be performed while preventing thermal deterioration of the NO _x purification catalyst in the device 42.

Therefore, according to the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment, the light fuel 23 and the heavy fuel 24 separated from the fuel are efficiently and effectively processed to prevent the deterioration of the combustion efficiency and the exhaust gas composition. it is possible to reduce the generation amount of soot generated due to fuel-24, NO _X occluded in purifying catalyst was NO _X of reduction efficiency, the improvement of the PM regeneration efficiency in the particulate matter trapping device 43 Can be planned.

An example in which the exhaust gas purification apparatus for an internal combustion engine according to the second embodiment of the present invention is applied to a diesel engine system will be described with reference to FIG.
FIG. 3 is a schematic diagram schematically showing the configuration of a diesel engine system of an exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention.
The exhaust gas purification apparatus for an internal combustion engine according to the present embodiment has the same configuration as that of a diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment is applied. Therefore, the exhaust gas from the internal combustion engine according to the first embodiment shown in FIG. The figure which shows the structure of the diesel engine system which applied the purification apparatus is abbreviate | omitted, and demonstrates using the schematic which shows the structure of a diesel engine system simply. Moreover, about the structure which is common in Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.
As shown in FIG. 3, the diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the embodiment of the present invention is applied has a heavy fuel 24 stored in a heavy fuel addition passage L5 shown in FIGS. A quality fuel storage tank 51 is provided.

  The heavy fuel 24 supplied from the fuel separator 17 to the heavy fuel storage tank 51 via the heavy fuel addition passage L5-1 is stored. The stored heavy fuel 24 is supplied to the particulate matter collecting device 43 only when necessary from the second exhaust addition valve 22-2 via the heavy fuel addition passage L5-2. Can do.

  For this reason, the PM filter in the particulate matter collection device 43 is supplied by supplying the heavy fuel 24 to the particulate matter collection device 43 in accordance with the filter bed temperature of the PM filter in the particulate matter collection device 43. The temperature can be increased to a temperature required for PM regeneration (for example, 550 ° C.).

As described above, according to the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment, the light fuel 23 and the heavy fuel 24 separated from the fuel are efficiently and effectively processed to prevent deterioration in combustion efficiency and exhaust gas composition. In addition, the amount of soot generated due to the heavy fuel 24 can be reduced, the reduction efficiency of NO _x stored in the NO _x purification catalyst can be improved, and the particulate matter trapping device 43 can be improved. Depending on the filter bed temperature of the PM filter, the heavy fuel 24 can be used for timely PM regeneration, and the particulate regeneration device 43 can improve the PM regeneration efficiency.

The example which applied the exhaust-gas purification apparatus of the internal combustion engine which concerns on Example 3 by this invention to the diesel engine system is demonstrated with reference to drawings.
The diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment is applied is the same as the configuration of the diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the first and second embodiments is applied. The addition control of the exhaust addition valve is performed. Accordingly, the illustration of the configuration of the diesel engine system to which the exhaust gas purification device for the internal combustion engine of the first embodiment as shown in FIGS. 1 and 2 is applied is omitted, and the engine to which the exhaust gas purification device for the internal combustion engine of the present embodiment is applied. The operation control method when performing PM regeneration in the particulate matter collecting apparatus in the system will be specifically described based on the flowchart of FIG.

[First PM regeneration control]
FIG. 4 is a flowchart showing the first PM regeneration control when PM regeneration is performed in the particulate matter collection device in the engine system to which the exhaust gas purification apparatus for an internal combustion engine according to this embodiment is applied.
As shown in FIG. 4, in the engine system to which the exhaust gas purification apparatus for the internal combustion engine according to the present embodiment is applied, the first PM regeneration control performs PM regeneration in the particulate matter collection device 43, so PM regeneration permission a step of performing control (step S11), and whether the PM elimination control is performed with determining whether ON (step S12), the the NO _X reduction of the NO _X catalyst for purifying nitrogen oxide purification device 42 jetted step of determining whether (step S13), and the first exhaust addition valve 22-1 (nitrogen oxide purification device 42 light fuel 23 on the upstream side shown in FIG. 1 for ejecting a light fuel 23 during NO _X reduction Is added to the second exhaust addition valve 22-2 (the particulate matter collecting device 43 shown in FIG. 1 upstream of the second exhaust addition valve 22-2) that ejects the heavy fuel 24 during PM regeneration. Addition control of the ejecting valve) Consisting the second PM step of performing a reproduction control for calculating a second PM regeneration control is calculated (step S14).
The specific process of the PM regeneration permission control in step S11 is performed based on the flowchart of FIG. The specific process of the second PM regeneration control in step S14 is performed based on the flowchart of FIG.

  First, in FIG. 4, in step S <b> 11, PM regeneration permission control is performed in order to perform PM regeneration in the particulate matter collection device 43. A specific process of the PM regeneration permission control in step S11 is shown in FIG.

[PM regeneration permission control]
FIG. 5 is a flowchart specifically showing PM regeneration permission control.
As shown in FIG. 5, the PM regeneration permission control includes a step of turning off PM regeneration control of the PM filter in the particulate matter collection device 43 (step S21), and a PM filter in the particulate matter collection device 43. A step of determining whether or not the PM volume amount of the battery is greater than or equal to a reference value (step S22), a step of determining whether or not a predetermined condition for permitting PM regeneration is satisfied (step S23), and turning on PM regeneration control (Step S24).

  First, in FIG. 5, in step S <b> 21, PM regeneration control of the PM filter in the particulate matter collection device 43 is turned off. Specifically, the second exhaust addition valve 22-2 is closed, and the heavy fuel 24 is ejected from the second exhaust addition valve 22-2 into the exhaust main passage 41 and supplied to the particulate matter collecting device 43. Stop doing. Then, after the PM regeneration control is turned off, the process proceeds to step S22.

  In step S22, it is determined whether the PM volume of the PM filter in the particulate matter collection device 43 is equal to or greater than a reference value. Since the PM filter has a limit in the amount of PM that can be adsorbed, PM regeneration is performed when the PM volume exceeds a reference value before the PM filter cannot adsorb PM. As a result of the determination in step S22, when it is determined that the PM volume of the PM filter is equal to or greater than the reference value (Yes in step S22), the process proceeds to step S23.

<PM regeneration permission conditions>
In step S23, it is determined whether or not a predetermined condition for permitting PM regeneration is satisfied. Specifically, the predetermined conditions for permitting PM regeneration include (a) whether the exhaust temperature is equal to or higher than a certain value, (b) whether the filter bed temperature of the PM filter is lower than a reference value, or (c) the exhaust temperature. Whether the exhaust gas temperature of the exhaust gas detected by the sensor 48-2 is less than a predetermined value, (d) whether the exhaust gas temperature of the exhaust gas detected by the exhaust temperature sensor 48-1 is less than a predetermined value, e) It is determined whether or not the water temperature is above a certain level, and (f) whether or not the air-fuel ratio (A / F) is in operation.

  Here, whether or not the exhaust temperature in step S23 is equal to or higher than a certain value (a) is obtained from the gas temperature of the exhaust gas discharged from the engine 11. Whether or not the filter bed temperature of the PM filter in step S23 is lower than the reference value (b) detects the filter bed temperature of the PM filter by the temperature sensor 45 provided in the particulate matter collection device 43, Determine if the filter bed temperature is below the reference value.

  Whether or not the exhaust gas temperature of the exhaust gas detected by the exhaust temperature sensor 48-2 in step S23 is less than a predetermined value (c) determines the exhaust gas temperature of the exhaust gas measured by the exhaust temperature sensor 48-2. Detection is performed to determine whether the exhaust gas temperature of the exhaust gas downstream of the particulate matter collection device 43 is lower than a predetermined value.

  Whether or not the exhaust gas temperature of the exhaust gas detected by the exhaust temperature sensor 48-1 in step S23 is less than a predetermined value (d) is determined by determining the exhaust gas temperature of the exhaust gas measured by the exhaust temperature sensor 48-1. And detecting whether the exhaust gas temperature of the exhaust gas downstream of the nitrogen oxide purification device 42 is less than a predetermined value.

  Whether the water temperature in step S23 is equal to or higher than a certain level (e) is determined by checking whether the water temperature is equal to or higher than a certain level by looking at the warm air of the catalyst. Whether or not the air-fuel ratio (A / F) in step S23 is operating (f) confirms whether or not the air-fuel ratio sensor is operating.

  If it is determined in step S23 that all predetermined conditions permitting PM regeneration are satisfied (all in step S23 is affirmative), the process proceeds to step S24.

  In step S24, PM regeneration control is turned on. Specifically, the second exhaust addition valve 22-2 is opened, and the heavy fuel 24 is ejected from the second exhaust addition valve 22-2 into the exhaust main passage 41 and supplied to the particulate matter collecting device 43. To do. Then, the filter bed temperature of the PM filter in the particulate matter collecting device 43 can be raised by the heavy fuel 24, and PM regeneration can be performed.

  And it transfers to step S12 shown in FIG. 4, and determines whether PM reproduction | regeneration control is ON. Since PM regeneration control is turned on in step S24 shown in FIG. 5, it is determined that PM regeneration control is turned on in step S12 shown in FIG. 4 (Yes in step S12), and the process proceeds to step S13.

Further, it is determined in step S13, whether implemented NO _X reduction of the NO _X catalyst for purifying nitrogen oxide purification device 42. As a result of the determination in step S13, when it is determined that NO _X reduction of the NO _X purification catalyst is being performed (Yes in step S13), the process proceeds to step S14.

In step S14, the addition control value of the first exhaust addition valve 22-1 that ejects the light fuel 23 during NO _X reduction is acquired, and the second exhaust addition valve 22-2 that ejects the heavy fuel 24 during PM regeneration. The second PM regeneration control for calculating the addition control value is performed. A specific process of the second PM regeneration control in step S14 is shown in FIG.

[Second PM regeneration control]
FIG. 6 is a flowchart specifically showing the second PM regeneration control.
As shown in FIG. 6, in the second PM regeneration control, a step of obtaining the addition control value of the first exhaust addition valve 22-1 (step S31) and a step of obtaining the current engine operating state (step S32). ), A step of calculating the addition control value of the second exhaust addition valve 22-2 (step S33), and a step of adding the heavy fuel 24 to the exhaust main passage 41 from the second exhaust addition valve 22-2 ( and step S34), and step of determining whether doing the NO _X reduction control of the NO _X catalyst for purifying nitrogen oxide purification device 42 (step S35), PM filter in the particulate matter trapping device 43 And determining whether or not the PM volume is less than or equal to a reference value (step S36).

<Acquisition control value of first exhaust addition valve>
In FIG. 6, first, in step S31, the addition control value of the first exhaust addition valve 22-1 is acquired. Specifically, (I) an addition amount to which light fuel 23 is ejected and added by the first exhaust addition valve 22-1 and (II) an addition to eject light fuel 23 by the first exhaust addition valve 22-1 (III) An addition interval until the light fuel 23 is next ejected from the first exhaust addition valve 22-1 by an ECU (not shown) is obtained. In step S31, the addition control value of the first exhaust addition valve 22-1 is acquired, and after the ECU instruction value is acquired, the process proceeds to step 32.

  In step S32, the current engine operating status is acquired. Specifically, the air amount (flow velocity) of the exhaust gas is obtained by an air flow meter that detects an exhaust amount (not shown). This is because when the exhaust gas flow rate is high, the amount of PM adsorbed increases, so that PM regeneration control is performed in consideration of the air amount (flow rate) of the exhaust gas. And in step S32, after calculating | requiring the air quantity (flow velocity) of exhaust gas, it transfers to step 33. FIG.

<Calculation of addition control value of second exhaust addition valve>
In step S33, the addition control value of the second exhaust addition valve 22-2 is calculated. Specifically, as the addition control value, (i) a heavy fuel 24 is injected by the second exhaust addition valve 22-2 and added, (ii) by the second exhaust addition valve 22-2. The number of additions for ejecting the heavy fuel 24, (iii) the addition interval until the heavy fuel 24 is next ejected from the second exhaust addition valve 22-2, and (iv) the second exhaust addition valve 22-2. The addition start time for starting the ejection of the heavy fuel 24 is obtained.

  Here, the heavy fuel 24 is ejected by the second exhaust addition valve 22-2 in step S33, and the addition amount (i) to be added ejects the light fuel 23 by the first exhaust addition valve 22-1. It is determined based on the addition amount to be added and the air amount (flow velocity) of the exhaust gas detected by an air flow meter that detects the exhaust amount (not shown). Thereby, the heavy fuel 24 can be added to the particulate matter collection device 43 in an appropriate amount from the second exhaust addition valve 22-2.

  Further, the number of times (ii) of adding the heavy fuel 24 by the second exhaust addition valve 22-2 in step S33 is obtained according to the filter bed temperature of the PM filter of the particulate matter collection device 43. Thereby, the addition frequency | count which adds the heavy fuel 24 from the 2nd exhaust gas addition valve 22-2 can be adjusted.

  Further, the addition interval (iii) of the heavy fuel 24 by the second exhaust addition valve 22-2 in step S33 is obtained by comparison with the addition interval of the light fuel 23 by the first exhaust addition valve 22-1. This is because the ejection timing of the heavy fuel 24 and the ejection timing of the light fuel 23 overlap, and the supply timing becomes the same period, so that the rich atmosphere of the exhaust gas supplied with the light fuel 23 and the supply of the heavy fuel 24 are achieved. This is because the rich atmosphere of the exhaust gas overlapped and becomes larger on the rich side.

  Therefore, for example, as shown in FIG. 7, the addition interval of the heavy fuel 24 by the second exhaust addition valve 22-2 is compared with the addition interval of the light fuel 23 by the first exhaust addition valve 22-1. The injection timing of the heavy fuel 24 by the second exhaust addition valve 22-2 is adjusted so that the injection timing of the light fuel 23 by the first exhaust addition valve 22-1 does not overlap. At this time, the addition interval of the heavy fuel 24 by the second exhaust addition valve 22-2 is the next heavy fuel 24 from the time when the heavy fuel 24 is first added by the second exhaust addition valve 22-2. 24 is a period until the start of addition for the first time. In addition, the addition interval of the heavy fuel 24 by the second exhaust addition valve 22-2 is set such that the light fuel 23 is first added by the first exhaust addition valve 22-1, and then the light fuel 23 is first added. This is the period until the start of addition.

  Here, for example, as shown in FIG. 8, the value of the air-fuel ratio (A / F) detected by the air-fuel ratio sensor 46-1 after the light fuel 23 is ejected from the first exhaust addition valve 22-1 is stoichiometric. (Thin line in the figure), the heavy fuel 24 is ejected from the second exhaust addition valve 22-2, and the value of the air-fuel ratio (A / F) detected by the air-fuel ratio sensor 46-2 is stoichiometric. It is assumed that it becomes lower (thick line in the figure). At this time, the heavy fuel 24 is ejected from the second exhaust addition valve 22-2 without considering the light fuel 23 ejected from the first exhaust addition valve 22-1 and detected by the air-fuel ratio sensor 46-2. The value of the air-fuel ratio (A / F) to be performed tends to be higher on the rich side than the value of the air-fuel ratio (A / F) detected by the air-fuel ratio sensor 46-1 (broken line in the figure).

  As a result, if the heavy fuel 24 is ejected from the second exhaust addition valve 22-2 without considering the light fuel 23 ejected from the first exhaust addition valve 22-1, the amount of fuel in the exhaust gas increases. When the filter is clogged with, for example, soot, the filter bed temperature of the PM filter of the particulate matter collecting device 43 is rapidly increased, and the filter may be damaged. Moreover, even if an oxidation catalyst is provided on the downstream side of the particulate matter collection device 43 to purify the exhaust gas, the oxidation catalyst cannot sufficiently purify the exhaust gas.

  On the other hand, as described above, the addition interval of the heavy fuel 24 by the second exhaust addition valve 22-2 is compared with the addition interval of the light fuel 23 by the first exhaust addition valve 22-1. By adjusting so that the injection timing of the heavy fuel 24 by the second exhaust addition valve 22-2 and the injection timing of the light fuel 23 by the first exhaust addition valve 22-1 do not overlap, the fuel in the exhaust gas is reduced. You can avoid becoming too many.

  In addition, the addition start timing (iv) at which the ejection of the heavy fuel 24 is started by the second exhaust addition valve 22-2 in step S33 starts the addition of the light fuel 23 from the first exhaust addition valve 22-1. It calculates | requires based on the addition start time, the addition space | interval which adds the light fuel 23 again by the 1st exhaust addition valve 22-1, and the air quantity of exhaust gas.

  Furthermore, in step S33, there is no information on the adjustment of the opening degree of the second exhaust addition valve 22-2, or a predetermined time or more has passed since the acquisition of the information on the adjustment of the opening degree of the second exhaust addition valve 22-2. If there is, information on opening degree adjustment of the second exhaust addition valve 22-2 is acquired. FIG. 9 shows a specific process for obtaining information on the degree of opening adjustment of the second exhaust addition valve 22-2 in step S33.

[Acquisition of opening adjustment information of second exhaust addition valve]
FIG. 9 is a flowchart specifically showing the acquisition of the opening adjustment information of the second exhaust addition valve 22-2.
As shown in FIG. 9, the information on the opening adjustment of the second exhaust addition valve 22-2 is acquired by the information on the opening adjustment of the second exhaust addition valve 22-2 for adding the heavy fuel 24. A step (step S41) of determining whether or not there is a predetermined time or more from the acquisition of information on the opening adjustment of the second exhaust addition valve 22-2 for adding the heavy fuel 24 last time; A step of stopping the addition of the light fuel 23 from the first exhaust addition valve 22-1 (step S42), and a step of starting obtaining information on the opening degree adjustment of the second exhaust addition valve 22-2 (step S43). And the step of determining whether or not the acquisition of the opening degree adjustment information of the second exhaust addition valve 22-2 is completed (step S44), and the stop of the addition of the first exhaust addition valve 22-1 is released. Step (step S45).

  In FIG. 9, first, in step S41, there is no information on opening degree adjustment of the second exhaust addition valve 22-2 for adding the heavy fuel 24, or for adding the previous heavy fuel 24. It is determined whether or not a certain period of time has elapsed since the acquisition of the opening adjustment information of the second exhaust addition valve 22-2. As a result of the determination in step S41, there is no information on the opening adjustment of the second exhaust addition valve 22-2 for adding the heavy fuel 24, or the second for adding the previous heavy fuel 24. When it is determined that a predetermined time or more has elapsed since the acquisition of the information on the opening degree adjustment of the exhaust addition valve 22-2 (Yes in Step S41), the process proceeds to Step S42.

  In step S42, the addition of the light fuel 23 from the first exhaust addition valve 22-1 is stopped, and the process proceeds to step S43.

  And in step S43, acquisition of the information of the opening degree adjustment of the 2nd exhaust addition valve 22-2 is started. Specifically, the heavy fuel 24 is appropriately jetted from the second exhaust addition valve 22-2 to the exhaust main passage 41 by an ECU (not shown), and it is confirmed whether a predetermined air-fuel ratio (A / F) is obtained.

  When the air-fuel ratio (A / F) is stoichiometric, the amount of heavy fuel 24 added is controlled to adjust the air-fuel ratio (A / F), but the second exhaust addition valve 22-2 is, for example, soot If the heavy fuel 24 is added from the second exhaust addition valve 22-2 and controlled based on the acquired information, the predetermined air-fuel ratio (A / F) is not achieved. For this reason, it is necessary to confirm the air-fuel ratio (A / F) and increase the amount of heavy fuel 24 added from the second exhaust addition valve 22-2 to a predetermined air-fuel ratio (A / F). . Thus, in order to perform proper PM regeneration, the air-fuel ratio (A / F) is confirmed by the air-fuel ratio sensor 46-2, and the addition amount of the heavy fuel 24 from the second exhaust addition valve 22-2 is controlled. To do.

  For example, when the air-fuel ratio (A / F) is to be adjusted to about 14.0, for example, the second exhaust addition valve is based on the previously acquired information on the opening degree adjustment of the second exhaust addition valve 22-2. When the value of the air-fuel ratio (A / F) detected by ejecting the heavy fuel 24 from 22-2 is, for example, about 15.0 or about 16.0, the second exhaust addition valve 22-2 The degree of opening is adjusted, and information on the degree of opening adjustment of the second exhaust addition valve 22-2 is acquired so that the air-fuel ratio (A / F) is about 14.0, for example. As a result, the opening degree of the second exhaust addition valve 22-2 can be adjusted and the air-fuel ratio (A / F) can be adjusted to about 14.0, for example.

  In step S44, it is determined whether or not acquisition of information on the opening degree adjustment of the second exhaust addition valve 22-2 has been completed. As a result of the determination in step S44, when it is determined that acquisition of information on the opening degree adjustment of the second exhaust addition valve 22-2 is completed (Yes in step S44), the process proceeds to step S45.

  In step S45, the stop of the addition of the first exhaust addition valve 22-1 is released, and the light fuel 23 is ejected from the first exhaust addition valve 22-1.

  When the calculation of the addition control value of the second exhaust addition valve 22-2 is completed in step S33 shown in FIG. 6, the process proceeds to step S34.

  In step S34, the heavy fuel 24 is added to the exhaust main passage 41 from the second exhaust addition valve 22-2. Specifically, the opening degree of the second exhaust addition valve 22-2 is adjusted, the heavy fuel 24 is jetted into the exhaust main passage 41 and supplied to the particulate matter collecting device 43, and the process proceeds to step S35.

In step S35, it is determined whether or not NO _X reduction control of the NO _X purification catalyst in the nitrogen oxide purification device 42 is being performed. As a result of the determination in step S35, when it is determined that the NO _x reduction control of the NO _x purification catalyst in the nitrogen oxide purification device 42 is being performed (Yes in step S35), the process proceeds to step S36.

  In step S36, it is determined whether the PM volume of the PM filter in the particulate matter collection device 43 is equal to or less than a reference value. As a result of the determination in step S36, when it is determined that the PM volume of the PM filter is equal to or less than the reference value (Yes in step S36), the PM regeneration control is terminated.

  On the other hand, as a result of the determination in step S12 shown in FIG. 4, when the PM regeneration control is determined to be OFF (No in step S12), the PM regeneration control is terminated.

If it is determined in step S13 that NO _X reduction of the NO _X purification catalyst has not been performed (NO in step S13), the process proceeds to step S15.

  In step S15, PM regeneration control is performed. Specifically, the second exhaust addition valve 22-2 is opened, and the heavy fuel 24 is ejected from the second exhaust addition valve 22-2 into the exhaust main passage 41 and supplied to the particulate matter collecting device 43. To do. Then, the filter bed temperature of the PM filter in the particulate matter collection device 43 is increased, and the PM collected by the PM filter is forcibly oxidized to regenerate PM.

  Then, after performing PM regeneration in step S15, PM regeneration control is terminated.

  Moreover, in step S22 shown in FIG. 5, as a result of determining whether or not the PM volume of the PM filter in the particulate matter collection device 43 is equal to or greater than a reference value, it is determined that the PM volume is not equal to or greater than the reference value. In the case of (No at Step S22), the PM regeneration control is terminated.

  As a result of the determination in step S23, if it is determined in step S23 that the predetermined condition is not satisfied for permitting PM regeneration (No in step S23), PM regeneration control is terminated.

Further, in step S35 shown in FIG. 6, it is determined whether or not the NO _x reduction catalyst of the NO _x purification catalyst in the nitrogen oxide purification device 42 is being controlled. As a result, the NO _x in the nitrogen oxide purification device 42 is determined. If it is determined that the NO _x reduction control of the purification catalyst is not being performed (No at step S35), the process proceeds to step S37.

  In step S37, PM regeneration control is performed in the same manner as the PM regeneration control in step 15 shown in FIG. Specifically, the heavy fuel 24 is supplied to the particulate matter collecting device 43 from the second exhaust addition valve 22-2, as described in Step 15 shown in FIG. The filter bed temperature of the inner PM filter is raised to perform PM regeneration. Then, after performing PM regeneration in step S37, PM regeneration control is terminated.

  Therefore, according to the engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the embodiment of the present invention is applied, when the PM regeneration is performed by the particulate matter collection device 43, the first exhaust addition valve 22-1. Based on the amount of light fuel 23 to be supplied, the number of additions, the addition interval, and the amount of air in the exhaust gas, the amount of addition of the heavy fuel 24 ejected from the second exhaust addition valve 22-2, the number of additions, The addition start time and the addition interval can be adjusted.

  For this reason, at the time of PM regeneration of the PM filter in the particulate matter collection device 43, the addition ratio of the heavy fuel 24 supplied to the particulate matter collection device 43 from the second exhaust addition valve 22-2 is controlled. Therefore, the PM filter in the particulate matter collection device 43 can be prevented from deteriorating and the fuel efficiency can be prevented from deteriorating, and the PM filter filter bed temperature can be stably set to a temperature required for PM regeneration. In addition, it is possible to prevent hydrocarbons and the like in the exhaust gas from being discharged by stabilizing the bed temperature while preventing the PM filter in the particulate matter collecting device 43 from deteriorating.

  In the present embodiment, the case where the present invention is applied to a diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine of the first embodiment as shown in FIGS. 1 and 2 is applied has been described. However, the present invention is not limited to this. Instead, the present invention may be applied to a diesel engine system to which the exhaust gas purification apparatus for an internal combustion engine according to the second embodiment as shown in FIG. 3 is applied.

  Thus, according to the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment, the addition amount, the number of additions, the addition start timing, and the addition interval of the heavy fuel 24 ejected from the second exhaust addition valve 22-2 are adjusted. By doing so, the light fuel 23 and the heavy fuel 24 separated from the fuel can be efficiently and effectively processed, and deterioration of combustion efficiency and exhaust gas composition can be prevented, and PM regeneration of the particulate matter collecting device 43 can be prevented. Efficiency can be improved.

As described above, the exhaust emission control device for an internal combustion engine according to the present invention uses light fuel as fuel for in-cylinder combustion, supplies light fuel to the nitrogen oxide purification device, and provides a particulate matter collecting device. By supplying heavy fuel, it is useful for efficiently and effectively treating light fuel and heavy fuel in the fuel to release NO _x and regenerate PM. while reducing the amount of generated reduction efficiency of the NO _X occluded in the NO _X purification catalyst, it is suitable for an internal combustion engine capable of improving the PM regeneration efficiency of the particulate matter trapping device.

1 is a schematic configuration diagram illustrating a diesel engine system to which an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention is applied. It is the schematic which shows the structure of the engine system shown in FIG. 1 simply. It is the schematic which shows the structure of a diesel engine system simply about the exhaust gas purification apparatus of the internal combustion engine which concerns on Example 2 of this invention. It is a flowchart showing the 1st PM regeneration control at the time of performing PM regeneration in a particulate matter collection device in an engine system to which an exhaust-air purification device of an internal-combustion engine concerning Example 3 of the present invention is applied. 5 is a flowchart specifically showing PM regeneration permission control. 6 is a flowchart specifically showing second PM regeneration control. It is explanatory drawing which shows simply the addition space | interval of light fuel and heavy fuel. It is explanatory drawing showing the air fuel ratio detected with an air fuel ratio sensor. It is a flowchart concretely showing acquisition of information on opening degree adjustment of the 2nd exhaust addition valve. It is a figure which shows an example of a structure of the exhaust gas purification apparatus of the conventional internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Engine 12 Fuel supply system 13 Combustion chamber 14 Intake system 15 Exhaust system 16 Fuel tank 17 Fuel separator 18 Fuel pump 19 Common rail 21 Fuel injection valve 22-1 First exhaust addition valve 22-2 Second exhaust addition valve 23 Light fuel 24 Heavy fuel 31 Intake 32 Turbocharger 33 Intercooler 34 Throttle valve 35 EGR passage 36 EGR valve 37 EGR cooler 41 Exhaust main passage 42 Nitrogen oxide purification device 43 Particulate matter collector 44 Air flow meter 45 Temperature sensor 46 −1, 46-2 Air-fuel ratio sensor 47 NO _X sensor 48-1, 48-2 Exhaust temperature sensor 51 Heavy fuel storage tank L1 Main fuel passage L2 Light fuel feed passage L3 Engine fuel passage L4 Light fuel addition passage L5, L5-1, L5-2 Heavy fuel addition passage

Claims (7)

A nitrogen oxide purification device in which a nitrogen oxide purification catalyst for purifying nitrogen oxide in exhaust gas in the exhaust passage is housed; and
An exhaust gas purification apparatus for an internal combustion engine having a particulate matter collecting device provided on the downstream side of the nitrogen oxide purification device and having a filter function for collecting particulate matter in the exhaust gas in the exhaust passage Because
A fuel separation device that separates fuel into light fuel with a lot of light components and heavy fuel with a lot of heavy components;
While using the light fuel as a fuel for engine combustion, using the light fuel at the time of reduction of nitrogen oxides stored in the nitrogen oxide purification catalyst,
An exhaust gas purification apparatus for an internal combustion engine, wherein the heavy fuel separated during PM regeneration for regenerating the PM trapping function by burning off the PM trapped by the particulate matter trapping apparatus is used. In claim 1,
A first exhaust addition valve that supplies the light fuel separated in the fuel separator to the upstream side of the nitrogen oxide purification device;
An internal combustion engine comprising: a second exhaust addition valve that supplies the heavy fuel separated in the fuel separation device between the nitrogen oxide purification device and the particulate matter collection device. Exhaust purification device. In claim 1 or 2,
An exhaust gas purification apparatus for an internal combustion engine, characterized in that an interval between the nitrogen oxide purification device and the particulate matter collecting device is a predetermined interval at which temperature transmission is unlikely to occur. In any one of Claims 1 thru | or 3,
An exhaust emission control device for an internal combustion engine, comprising a heavy fuel storage tank for storing the heavy fuel separated by the fuel separation device. In any one of Claims 2 thru | or 4,
When performing PM regeneration in the particulate matter collection device,
Based on the amount of addition of the light fuel from the first exhaust addition valve and the amount of air of the exhaust gas,
An exhaust gas purification apparatus for an internal combustion engine, wherein an addition amount for adding the heavy fuel is adjusted from the second exhaust addition valve. In claim 5,
An exhaust gas purification apparatus for an internal combustion engine, wherein the number of times of adding the heavy fuel is adjusted from the second exhaust gas addition valve in accordance with a bed temperature in the particulate matter trapping device. In claim 5 or 6,
Based on the addition start timing for starting the addition of the light fuel from the first exhaust addition valve, the addition interval for adding the light fuel again, and the amount of air in the exhaust gas,
An exhaust gas purification apparatus for an internal combustion engine, characterized by adjusting an addition start timing at which the addition of the heavy fuel is started from the second exhaust addition valve and an addition interval at which the heavy fuel is added again.

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