JP4737142B2 - 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 an aroma component in fuel and improves the purification performance of harmful components in exhaust gas discharged from the internal combustion engine.

  In general, exhaust gas of diesel engines contains particulate matter mainly composed of carbon (hereinafter referred to as PM (Particulate Matter)) and is known to cause air pollution. It is necessary to capture and remove particulate matter.

In recent years, exhaust gas control of diesel engines, for example, nitrogen oxide (NO _x ) aftertreatment technology has been studied, and the purification performance of the nitrogen oxide (NO _x ) purification catalyst is remarkably dependent on the properties of light oil added as a reducing agent. Different. The light oil that is the reducing agent contains, for example, a benzene hydrocarbon (hereinafter referred to as “aromatic component”) that is an aromatic compound such as benzene, toluene, and xylene. The aromatic content contained in gas oil is not suitable as a reducing agent for NO _X.

Therefore, an exhaust emission control device for an internal combustion engine that uses a mixed fuel obtained by mixing a plurality of types of conventional fuels has been proposed. As an exhaust purification device for an internal combustion engine using a mixed fuel, there is the following (Patent Document 1).
FIG. 4 is a diagram showing a configuration of a conventional exhaust gas purification apparatus for an internal combustion engine. As shown in FIG. 4, a conventional exhaust purification device 100 for an internal combustion engine includes a nitrogen oxide (NO _x ) purification catalyst 102 interposed in an exhaust pipe 101 of an internal combustion engine that exhausts exhaust gas, and the NO _x use. A reducing agent adding means 104 for adding a reducing agent 103 for reducing nitrogen oxide (NO _x ) and an aroma content removing means 106 for removing the aroma content 105 a contained in the light oil 105 are provided upstream of the purification catalyst 102. Yes. The reducing agent adding means 104 includes a light oil tank 107 that stores light oil 105 and an addition valve 108 that adds the reducing agent 103 into the exhaust pipe 101, and adds the reducing agent 103 into the exhaust pipe 101.

  Further, the aroma content removing means 106 includes a removal solvent tank 111 that stores an aroma content removal solvent 110 (for example, sulfuric acid or a sulfate solution) that is blended in the light oil 105 and separates the aroma content 105 a, and the light oil 105 contains this aroma. The aroma fraction separator 112 that mixes the fraction removal solvent 110 to precipitate the aroma fraction 105a and separates it into the reducing agent 103 and the aroma fraction 105a, and the recovery means that separates and collects the aroma fraction 105a and the aroma fraction removal solvent 110. 113. The recovery means 113 includes a recovery tank 115 that stores a mixed liquid 114 of the aroma content 105a separated by the aroma content separator 112 and the aroma content removal solvent 105, a heater 115a that distills the aroma content 105a from the liquid mixture 114, And a return pump 116 for circulating the aroma content removing solvent 110 after distillation to the removing solvent tank 111.

The removal solvent tank 111 is provided with a pump 111p, and the aroma removal solvent 110 is supplied to the aroma separation separator 112 by a control device (not shown). The light oil tank 107 is provided with a pump 107p, and supplies the light oil 105 to the aroma fraction separator 112 in accordance with an instruction from a control device (not shown). The aroma fraction separator 112 receives the light oil 105 supplied from the light oil tank 107 and the aroma content removal solvent 110 supplied from the removal solvent tank 111, and is sedated for a predetermined time, so that the reducing agent 103, which is the light oil of the supernatant. And a mixed solution 114 containing the aroma portion 105a. The pump 112p in the aroma fraction separator 112 is driven, and the light oil 105 from which the aroma fraction 105a has been removed is added to the upstream side of the nitrogen oxide (NO _x ) purification catalyst 102 as the reducing agent 103. In addition, the mixed liquid 114 containing the aroma portion 105 a opens the electromagnetic valve 120 and is discharged to the recovery tank 115.

  The vaporized aroma portion 105a is sent to a fuel tank 117 for engine combustion, mixed with light oil for combustion, and supplied to the engine 118. In addition, the aroma-removing solvent 110 remaining in the recovery tank 115 is recovered in the removal solvent tank 111 via the removal solvent recovery passage 119 by driving the return pump 116 and reused.

  In this way, in the conventional exhaust purification device 100 for an internal combustion engine, the supernatant light oil from which the aroma content 105 a has been removed by the aroma content removal means 106 is added as the reducing agent 103 to the upstream side of the nitrogen oxide purification catalyst 102. The purification performance of the added nitrogen oxide in the exhaust gas G is improved.

JP 2006-132435 A

However, in the exhaust purification system of a conventional internal combustion engine, for the purpose only possible to playback of the NO _X purification catalyst 102, the separated aromatic content 105a process is not sufficiently taken into account, there is a problem in that.

  That is, in the conventional exhaust gas purification apparatus 100 for an internal combustion engine, the vaporized high-concentration aroma component 105a is supplied to the fuel tank 117 for engine combustion, mixed with, for example, light oil for combustion, and supplied to the engine 118. However, if the high-concentration aroma portion 105a is continuously supplied, the aroma portion 105a exceeds the allowable range of the engine 118, and as a result, the amount of soot generated due to the increased aroma portion 105a further increases. There is.

  Normally, a high concentration aroma portion 105a of about 20%, for example, is sent to the engine 118, but the high concentration aroma portion 105a is gradually concentrated in the recovery tank 115 along with a long-time operation. There is a problem that the combustion efficiency of the engine 118 is deteriorated by supplying the concentrated and vaporized aroma portion 105a for combustion of the engine.

  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”). When the aroma content 105a increases, the amount of PM generated due to the aroma content 105a further increases and the PM regeneration frequency increases. There is a problem.

Moreover, by burning aromatic content 105a, since the NO _X purification catalyst 102 is poisoned, the reproduction frequency of the NO _X purification catalyst 102 is also increased, the catalyst efficiency is lowered, there is a problem that.

Furthermore, in order to maintain the catalytic activity of the NO _x purification catalyst 102, the catalyst bed temperature is low, for example, about 200 to 400 ° C., whereas in order to oxidatively decompose the aroma content 105a, further, Since high temperature is required, there is a problem that the oxidative decomposition of the aroma portion 105a does not proceed.

  As a result, if the oxidative decomposition of the aroma portion 105a is not sufficiently performed, there is a problem that exhaust gas containing the aroma portion 105a is released into the atmosphere and causes environmental pollution.

  The present invention has been made in view of the above problems, and can separate aroma components in the exhaust gas and add them from the addition valve into the exhaust system and into the engine cylinder, thereby improving the purification performance of the aroma components. An object of the present invention is to provide an exhaust purification device for an internal combustion 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 purification device, comprising: a fuel separation device that separates an aroma content in fuel and separates the aroma-free fuel not containing the aroma content into an aroma-containing fuel containing the aroma content, Used as fuel for engine combustion, uses the aroma-free fuel during the reduction of nitrogen oxides stored in the catalyst for purifying nitrogen oxides, and burns down PM collected in the particulate matter collection device Characterized by using the aroma-containing fuel and the separation when the PM regeneration for reproducing PM trapping function Te.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, a first exhaust addition valve that supplies the aroma-free fuel separated in the fuel separation apparatus to the upstream side of the nitrogen oxide purification apparatus, and the fuel separation apparatus And a second exhaust addition valve for supplying the aroma-containing fuel separated in step 1 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 an aroma-containing fuel tank that stores the aroma-containing fuel separated by the fuel separator.

  According to the present invention, the fuel separation device for separating the aroma content in the fuel into the aroma-free fuel and the aroma-containing fuel is provided, and the aroma-free fuel can be used as a fuel for combustion in the engine cylinder at all times. For this reason, while being able to suppress PM production | generation generate | occur | produced by engine combustion, PM regeneration frequency of a particulate matter collection apparatus can be reduced.

  In addition, since the first exhaust addition valve for supplying the aroma-free fuel to the upstream side of the nitrogen oxide purification device is provided, the aroma-free fuel can be constantly supplied into the nitrogen oxide purification device. By supplying a highly reactive reducing agent to the purification catalyst, the reduction efficiency of nitrogen oxides stored in the nitrogen oxide purification catalyst can be increased.

  Also, by adding the aroma-free fuel to the nitrogen oxide purification device to such an extent that the nitrogen oxide purification catalyst does not thermally degrade, the particulate matter collecting device while suppressing the thermal degradation of the nitrogen oxide purification catalyst The filter bed temperature inside can be raised.

  In addition, since the second exhaust addition valve that supplies the aroma-containing fuel between the nitrogen oxide purification device and the particulate matter collection device is provided, the aroma-containing fuel is always supplied to the particulate matter collection device. By doing so, the filter bed temperature in a particulate matter collection device can be raised.

  In addition, since the aroma content in the fuel is oxidized during PM regeneration, the aroma content can be processed efficiently, and discharge of the aroma content can be suppressed. Thereby, the generation amount of soot generated due to the aroma can be suppressed.

  Further, since the aroma-containing fuel tank for storing the aroma-containing fuel separated by the fuel separator is provided, the particulate matter collecting device can be supplied only when necessary.

  Therefore, by efficiently and effectively treating the aroma content in the fuel, it is possible to suppress the discharge of the aroma content, reduce the amount of soot generated due to the aroma content, and to purify nitrogen oxides The reduction efficiency of nitrogen oxides occluded in the catalyst and the PM regeneration efficiency of the particulate matter collection device can be improved.

  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 fuel separator 17, a main fuel passage L1, a fuel pump 18, a common rail 19, a fuel injection valve 21, cutoff valves V1 to V3, a first exhaust addition valve 22-1 and a second. The exhaust addition valve 22-2, the aroma-free fuel supply passage L2, the engine fuel passage L3, the aroma-free fuel addition passage L4, and the aroma-containing fuel addition passage L5 are configured. The fuel tank 16 is provided with a fuel oxygen concentration sensor (fuel oxygen concentration detecting means) 22 for detecting the oxygen concentration of the fuel.

  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 aroma in the fuel supplied from the fuel tank 16 and separates it into an aroma-free fuel 23 that does not contain the aroma and an aroma-containing fuel 24 that contains the aroma.

  In this embodiment, the fuel separation device 17 may be any system that can selectively separate the aroma content in the fuel. For example, a method for extracting and separating the aroma content, a method using a separation membrane, and the like. However, it is not limited to these.

  The fuel pump 18 increases the pressure of the aroma-free fuel 23 pumped up from the fuel separator 17 via the aroma-free 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 aroma-free fuel 23 supplied from the fuel pump 18 at a predetermined pressure and distributes it to the fuel injection valves 21. A fuel injection valve 21 that is an electromagnetic valve injects fuel into the combustion chamber 13.

  Thereby, since the aroma-free fuel 23 can be injected and supplied into the combustion chamber 13 from each fuel injection valve 21, the aroma-free fuel 23 can always be used as a fuel for in-cylinder combustion. As a result, it is possible to suppress the PM generation derived from the aroma generated by the in-cylinder combustion, and the generation of particulate matter (PM) collected in the particulate matter collection device 43 is reduced. The PM regeneration frequency for forcibly oxidizing PM and regenerating the PM trapping function can be reduced.

  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 oxide purification device 42 in which a nitrogen oxide (NO _x ) purification catalyst for purifying nitrogen oxide in the exhaust gas is accommodated on the exhaust main passage 41, and a downstream side thereof. A particulate matter collecting device 43 having a PM filter for collecting the particulate matter in the exhaust gas is provided.

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.

  The particulate matter collection device 43 includes a PM filter that collects particulate matter (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.

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

Since the aroma-free fuel 23 from the first exhaust addition valve 22-1 can be always supplied to the upstream side of the nitrogen oxide purification device 42, a nitrogen oxide purification device 42 NO _X purification catalyst in the reactive High reducing agent can be supplied. As a result, the reduction efficiency of NO _x stored in the NO _x purification catalyst in the nitrogen oxide purification device 42 can be increased.

Also, the aroma-free fuel 23 from the first exhaust addition valve 22-1 is supplied to the nitrogen oxide purification device 42, a temperature (e.g., 400 thermal degradation of the NO _X catalyst for purifying nitrogen oxide purification device 42 does not occur The filter bed temperature of the PM filter in the particulate matter trapping device 43 can be increased while suppressing the thermal deterioration of the NO _x purification catalyst.

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

  Since the aroma-containing fuel 24 can be always supplied from the second exhaust addition valve 22-2 between the nitrogen oxide purification device 42 and the particulate matter collecting device 43, the inside of the particulate matter collecting device 43 The filter bed temperature of the PM filter can be raised.

  Further, by supplying the aroma-containing fuel 24 to the particulate matter collecting device 43 in which the aroma-free 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, it is possible to efficiently increase the filter bed temperature (for example, 550 ° C.) required for the PM regeneration of the PM filter in the particulate matter collection device 43 to perform the PM regeneration of the particulate matter collection device 43.

  As for the treatment of aroma, in the conventional exhaust gas purification apparatus for an internal combustion engine as shown in FIG. 4, the concentrated aroma is used for engine combustion, and the amount of soot generated due to the aroma is increased. Therefore, the combustion efficiency of the engine is deteriorated, and the treatment for the aroma is not sufficiently considered.

On the other hand, in the present invention, as described above, the aroma-free fuel 23 is always used as a combustion fuel, so that no soot is generated in the exhaust gas and the PM regeneration frequency can be reduced. Further, upon reduction of the nitrogen oxide purification device of nitrogen oxides occluded in the NO _X purifying catalyst 42, by using the aroma-free fuel 23 as the reducing agent, it is possible to increase the NO _X reduction efficiency. Further, by supplying the aroma-containing fuel 24 to the particulate matter collecting device 43 during PM regeneration, it is used to increase the filter bed temperature and increase the PM regeneration efficiency, and to burn and consume the aroma, resulting in a high concentration The amount of soot generated due to the aroma content can be greatly reduced, and the aroma content can be processed efficiently and effectively.

Therefore, the aroma content in the fuel can be efficiently and effectively processed, the discharge of the aroma content can be suppressed, and the amount of soot generated due to the high concentration aroma content can be greatly reduced. Further, it is possible to improve the reduction efficiency of nitrogen oxides occluded in the NO _x purification catalyst and the PM regeneration efficiency of the particulate matter collection device.

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 interval between the nitrogen oxide purification device 42 and the particulate matter collection device 43 is secured at a predetermined interval so that the temperature transmission between the nitrogen oxide purification device 42 and the particulate matter collection device 43 hardly occurs. To do.

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 collection device 43 can be increased.

  A metering valve (not shown) is also provided in the aroma-free fuel addition passage L4 and the aroma-containing 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, purify the nitrogen oxides of the exhaust system 15 at an appropriate amount and at an appropriate timing of the aroma-free fuel 23 and the aroma-containing fuel 24. It is added and supplied to the device 42 and 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. Also, air-fuel ratio sensors 46-1 and 46-2 for detecting the oxygen concentration in the exhaust gas between the upstream side of the nitrogen oxide purification device 42 and between the nitrogen oxide purification device 42 and the particulate matter collection device 43, A NO _x sensor 47 for detecting the nitrogen concentration downstream of the particulate matter collection device 43 is provided.

  Further, in the present embodiment, the first exhaust addition valve 22-1 and the second exhaust addition valve 22-2 are capable of pulverizing and ejecting the aroma-free fuel 23 or the aroma-containing fuel 24. The invention is not particularly 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 via an external input circuit, and based on these signals, the fuel injection valve 21, the first exhaust addition valve 22-1, and the second exhaust. Various controls relating to the operating state of the engine 11 such as opening / closing control of the addition valve 22-2 are performed. Aroma The ECU is for jetting the amount of aroma-free fuel 23 jetted from the first exhaust addition valve 22-1 based the NO _X emissions of the NO _X sensor 47, the second exhaust addition valve 22-2 The addition amount of the contained fuel 24 is adjusted.

  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 that separates the aroma content in the fuel and separates it into the aroma-free fuel 23 and the aroma-containing fuel 24. 17, the aroma-free fuel 23 can always be used as a fuel for in-cylinder combustion. As a result, PM generation generated by engine in-cylinder combustion can be suppressed, and the PM regeneration frequency can be reduced.

Further, since the first exhaust addition valve 22-1 for supplying the aroma-free fuel 23 to the upstream side of the nitrogen oxide purification device 42 is provided, the aroma-free fuel 23 is nitrogenated from the first exhaust addition valve 22-1. can be always supplied to the oxide purifier 42, it is possible to provide a highly reactive reducing agent to the NO _X purification catalyst, nitrogen oxide purifier nitrogen oxide occluded in the NO _X purification catalyst in 42 The reduction efficiency of can be increased.

Further, by adding the aroma-free fuel 23 to a temperature at which the NO _x purification catalyst in the nitrogen oxide purification device 42 is not thermally degraded (for example, 400 ° C.), the thermal degradation of the NO _x purification catalyst is suppressed. The filter bed temperature of the PM filter in the particulate matter collection device 43 can be increased.

  Further, since the second exhaust addition valve 22-2 for supplying the aroma-containing 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 aroma-containing fuel 24 can be constantly supplied between the nitrogen oxide purification device 42 and the particulate matter collecting device 43, and the filter bed temperature of the PM filter in the particulate matter collecting device 43 is increased. be able to. For this reason, it can raise efficiently to the filter bed temperature (for example, 550 degreeC) required for PM reproduction | regeneration of PM filter in the particulate matter collector 43. FIG.

Further, in the conventional exhaust purification device for an internal combustion engine as shown in FIG. 4, the concentrated aroma is used for engine combustion, the amount of soot generated due to the aroma 105a is increased, and the combustion efficiency of the engine is deteriorated. I am letting. On the other hand, in the present invention, since the aroma-free fuel 23 is always used as a combustion fuel, soot is not generated in the exhaust gas, and the PM regeneration frequency can be reduced. Further, upon reduction of the nitrogen oxide purification device of nitrogen oxides occluded in the NO _X purifying catalyst 42, by using the aroma-free fuel 23 as the reducing agent, it is possible to increase the NO _X reduction efficiency. Furthermore, by supplying the aroma-containing fuel 24 to the particulate matter collection device 43 during PM regeneration, the filter bed temperature can be raised, PM regeneration efficiency can be increased, and the aroma is combusted and consumed, resulting in a high concentration. The amount of soot generated due to the aroma can be greatly reduced, and the aroma can be efficiently and effectively processed.

  Thus, by efficiently and effectively treating the aroma content in the fuel, discharge of the aroma content can be suppressed, generation of soot generated due to the aroma content can be greatly suppressed, and nitrogen oxidation The reduction efficiency of nitrogen oxides occluded in the product purification catalyst and the PM regeneration efficiency of the particulate matter collection device can be improved.

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 an aroma that stores an aroma-containing fuel 24 in an aroma-containing fuel addition passage L5 shown in FIGS. A contained fuel tank 51 is provided.

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

  For this reason, by supplying the aroma-containing fuel 24 to the particulate matter collecting device 43 in accordance with the filter bed temperature of the PM filter in the particulate matter collecting device 43, the PM filter in the particulate matter collecting device 43 is provided. 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 aroma content in the fuel is efficiently and effectively processed, and the discharge of the aroma content is suppressed, while the particulate matter collection device 43 has the inside. Depending on the filter bed temperature of the PM filter, the aroma-containing fuel 24 can be used for timely PM regeneration.

As described above, the exhaust gas purification apparatus for an internal combustion engine according to the present invention separates the aroma content in the fuel, separates it into the aroma-free fuel and the aroma-containing fuel, and uses the aroma-free fuel as a fuel for in-cylinder combustion. Used to supply the aroma-free fuel to the nitrogen oxide purification device and supply the aroma-containing fuel to the particulate matter collection device, so that the aroma content in the fuel can be processed efficiently and effectively, and NO _x release, PM Useful for regeneration, reducing the amount of soot generated due to aroma, and improving the reduction efficiency of NO _x stored in the NO _x purification catalyst and the PM regeneration efficiency of the particulate matter collection device Suitable for internal combustion engines capable of

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 figure which shows the structure of the conventional exhaust gas purification apparatus of an 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 Aroma-free fuel 24 Aroma-containing 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 and 46-2 fuel ratio sensor 47 NO _X sensor 51 aromacontaining fuel tank L1 main fuel passage L2 aroma-free fuel delivery passage L3 engine fuel path L4 aroma-free fuel addition passage L5, L5-1, L5-2 aroma Contained fuel addition passage

Claims (4)

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 aroma in the fuel and separates it into an aroma-free fuel that does not contain the aroma and an aroma-containing fuel that contains the aroma;
While using the aroma-free fuel as a fuel for engine combustion, using the aroma-free fuel during the reduction of nitrogen oxides stored in the nitrogen oxide purification catalyst,
An exhaust gas purification apparatus for an internal combustion engine, wherein the separated aroma-containing fuel is used at the time of PM regeneration in which PM collected by the particulate matter collection device is burned away to regenerate the PM collection function. In claim 1,
A first exhaust addition valve for supplying the aroma-free fuel separated in the fuel separation device to the upstream side of the nitrogen oxide purification device;
An internal combustion engine comprising: a second exhaust addition valve that supplies the aroma-containing 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 gas purification apparatus for an internal combustion engine, comprising: an aroma-containing fuel tank that stores the aroma-containing fuel separated by the fuel separator.

Images