JP4626439B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust emission control device for an internal combustion engine.

Internal combustion engine to carry out combustion at a lean air-fuel ratio are known, the exhaust passage of such an internal combustion engine, NO _X catalyst device for purifying NO _X is arranged. The NO _x catalyst device can store NO _x well from a lean air-fuel ratio exhaust gas with a high oxygen concentration, but cannot store NO _x without limitation. Thus, before _the NO _X storage amount of the NO _X catalyst device is saturated, to release the occluded NO _X by lowering the oxygen concentration in the exhaust gas, unburned exhaust gas NO _X which were released It is necessary to regenerate the NO _x catalyst device for reducing and purifying with reducing substances such as HC and CO.

  Generally, in order to reduce the oxygen concentration in the exhaust gas and to make unburned HC etc. exist in the exhaust gas, the combustion air-fuel ratio is made rich, or fuel is injected into the cylinder in the expansion stroke or exhaust stroke However, if the air-fuel ratio in the cylinder is made rich in this way, the amount of particulate generation in the cylinder increases.

Thereby, as the amount of particulates does not increase, but to supply the particulate fuel is carried into the engine exhaust system, particulate fuel is not well react with oxygen and NO _X. Thereby be supplied to the particulate fuel simply exhaust passage, it can not be reduced satisfactorily oxygen concentration in the exhaust gas, also satisfactorily reduce and purify the released NO _X from NO _X catalyst device I can't do that either.

Intended to solve this problem, by disposing a HC adsorbing oxidizer between the engine exhaust system fuel supply device and the NO _X catalyst device, the particulate fuel supplied from the fuel supply device HC adsorbing It has been proposed that the gas is adsorbed by an oxidizer and then released as a highly reactive gas by evaporation (see, for example, Patent Document 1). Gaseous fuel that has been thus released, along with lowering the oxygen concentration in the exhaust gas flowing in good react with oxygen in the exhaust gas in the HC adsorbing oxidizer to NO _X catalyst device flows into the NO _X catalyst device and reacted well with released NO _X from NO _X catalyst device is reduced purify NO _X Te.

In this exhaust purification device, unburned HC generated during combustion is adsorbed to the HC adsorption oxidation device, and when this adsorption HC starts combustion using oxygen in the exhaust gas in the HC adsorption oxidation device, Particulate fuel is supplied from the supply device, and the regeneration process of the NO _x catalyst device is performed.

JP2003-97255A JP 2004-68784 A JP 2002-295242 A

Thus, the exhaust gas purifying apparatus described above, even though the NO _X storage amount of the NO _X catalyst device is required regeneration treatment becomes saturated immediately before, the HC that is already adsorbed on the HC adsorbing oxidizer combustion If it does not start, the reproduction process will not be performed. Thereby, when the reproduction process is judged to be necessary in NO _X catalyst device, NO _X in the reproduction processing period corresponding to the NO _X storage amount of the catalyst device, particulate fuel gradually gas adsorbed to the HC adsorbing oxidizer is released as Jo fuel, burned to consume most of the oxygen in the exhaust gas in the HC adsorbing oxidizer, allowed to flow into the exhaust gas slightly richer containing excess gaseous fuel to the NO _X catalyst device the NO _X released by reduction purification Te, thus it is considered to be all reduced and purified NO _X that is occluded in the NO _X catalyst device. For this purpose, when it is determined that the regeneration process is necessary in the NO _x catalyst device, the fuel amount necessary for the regeneration process is supplied to the upstream side of the HC adsorption oxidizer by the fuel supply device.

  The particulate fuel thus supplied to the upstream side of the HC adsorption / oxidation device is adsorbed by the HC adsorption / oxidation device and then evaporated to be released as a gaseous fuel. Although oxygen in the gas is consumed, when the temperature of the HC adsorption oxidizer immediately before the supply of the particulate fuel is relatively low, the temperature of the HC adsorption oxidizer does not become so high even if the evaporated fuel is burned. When the amount of fuel adsorbed by the HC adsorption / oxidation device decreases, the fuel hardly evaporates and some fuel may remain in the HC adsorption / oxidation device.

If fuel remains in the HC adsorption oxidizer in this way, the HC adsorption oxidizer may not be able to adsorb all the particulate fuel supplied as the required amount in the next regeneration process. At this time, the particulate fuel that is not adsorbed Since the reactivity is low, the exhaust emission is deteriorated by simply passing through the NO _x catalyst device.

Accordingly, an object of the present invention, NO _X catalyst device and, NO _X catalyst and HC adsorbing oxidizer disposed in an exhaust upstream side of the device, NO _X catalyst device regeneration process the amount of particulate fuel required to the HC adsorption In an exhaust gas purification apparatus for an internal combustion engine having a fuel supply device for supplying to an oxidizer, it is intended to suppress the deterioration of exhaust emission due to particulate fuel that passes through the NO _x catalyst device without being adsorbed by the HC adsorption oxidizer. .

The exhaust gas purification apparatus for an internal combustion engine according to claim 1 of the present invention occludes NO _x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and occludes when the air-fuel ratio of the exhaust gas is the stoichiometric air-fuel ratio or rich. and NO _X catalyst device that releases the NO _X, and HC adsorption oxidizer having an oxidizing function while adsorbing hydrocarbons of the NO _X catalyst exhaust gas is disposed in the exhaust upstream side of the device, the NO _X catalyst device the amount of particulate fuel necessary for the reproduction processing to reduce and purify by releasing NO _X from, comprising a fuel supply device for supplying to the HC adsorbing oxidizer, comprising a residual fuel estimating means, when the current reproduction process only when the residual fuel has been determined to be present in the HC within --AO device, wherein for the current playback processing from the supply of the particulate fuel by the fuel supply device for the previous regeneration processing In between the charge supply device until the particulate fuel is supplied, which comprises carrying out temperature increase control for raising the temperature of the HC adsorbing oxidizer.

According to a second aspect of the present invention, the exhaust gas purification apparatus for an internal combustion engine stores NO _x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and stores when the air-fuel ratio of the exhaust gas is the stoichiometric air-fuel ratio or rich. and NO _X catalyst device that releases the NO _X, and HC adsorption oxidizer having an oxidizing function while adsorbing hydrocarbons of the NO _X catalyst exhaust gas is disposed in the exhaust upstream side of the device, the NO _X catalyst device from the amount of particulate fuel necessary for the reproduction processing to reduce and purify by releasing NO _X, comprising a fuel supply device for supplying to the HC adsorbing oxidizer, by the fuel supply device for the previous regeneration processing During the period from when the particulate fuel is supplied until the particulate fuel is supplied from the fuel supply device for the current regeneration process, temperature rise control is performed to raise the temperature of the HC adsorption oxidation device, and During the time of this reproduction process from the control is carried out from said fuel supply device until supply particulate fuel, and providing a temperature drop period of the HC adsorbing oxidizer.

An exhaust purification system of an internal combustion engine according to claim 3 of the present invention, in the exhaust purification system of an internal combustion engine according to claim 1, from said fuel supply device when the current reproduction process after the Atsushi Nobori control is performed The temperature reduction period of the HC adsorption oxidizer is provided until the particulate fuel is supplied.

According to the exhaust purification system of the internal combustion engine that by the present invention, the particulate fuel from a fuel supply system for this regeneration process from the supply of the particulate fuel from the fuel supply system for the previous regeneration processing Until it is supplied, temperature increase control is performed to raise the temperature of the HC adsorption oxidizer so that almost no residual fuel exists in the HC adsorption oxidizer. As a result, even if a part of the particulate fuel supplied by the fuel supply device for the previous regeneration process remains in the HC adsorption oxidizer, the residual fuel is forcibly released by the temperature rise control. In the current regeneration process, almost all of the required amount of particulate fuel supplied by the fuel supply device can be adsorbed by the HC adsorption oxidizer, and a part of it can be adsorbed by the residual fuel on the HC adsorption oxidizer. It is possible to prevent the exhaust emission from being deteriorated by passing through the NO _x catalyst device without being able to be performed.

According to the exhaust gas purification apparatus for an internal combustion engine according to claim 1 or 3 of the present invention, the apparatus further comprises a residual fuel estimation means, and when it is determined that residual fuel is present in the HC adsorption oxidizer during the current regeneration process. However, since the temperature increase control is performed, it is possible to prevent the temperature increase control from being performed unnecessarily when there is no residual fuel in the HC adsorption oxidation apparatus.

According to the exhaust gas purification apparatus for an internal combustion engine according to claim 2 or 3 of the present invention, it is further possible that the particulate fuel is supplied from the fuel supply device during the current regeneration process after the temperature raising control is performed. The temperature reduction period of the HC adsorption oxidizer is provided. As a result, the particulate fuel is supplied from the fuel supply device after the temperature of the HC adsorption oxidizer heated by the temperature rise control is lowered by the temperature drop period. Can be adsorbed to the HC adsorption oxidizer.

FIG. 1 is a schematic view showing an exhaust gas purification apparatus for an internal combustion engine according to the present invention. In the figure, 1 is a turbocharger. The compressor 1a of the turbocharger 1 is arranged in the intake passage 2 leading to the intake manifold IM of the internal combustion engine, while the turbine 1b of the turbocharger 1 is arranged in the exhaust passage 3 leading to the exhaust manifold EM of the internal combustion engine. An internal combustion engine is an internal combustion engine (for example, a diesel engine) that performs lean combustion, and a relatively large amount of NO _x is contained in exhaust gas.

In order to purify this NO _x , a NO _x catalyst device 6 is disposed downstream of the turbine 1b in the exhaust passage 3. The NO _x catalyst device 6 has a monolith support or pellet support on which an NO _x storage catalyst described below and a noble metal catalyst such as platinum Pt are supported using alumina or the like. The NO _x catalyst device 6 also has a NO _x storage catalyst and a noble metal catalyst on the partition wall surface and pores of the particulate filter in which the exhaust gas passes through the partition wall made of a porous material such as cordierite. It may be supported.

The NO _x storage catalyst is selected from, for example, alkali metals such as potassium K, sodium Na, lithium Li and cesium Cs, alkaline earth metals such as barium Ba and calcium Ca, and rare earths such as lanthanum La and yttrium Y. Is at least one. This _the NO _X storage catalyst, when the air-fuel ratio of the exhaust gas is lean, i.e., occludes NO _X when the oxygen concentration is high, the air-fuel ratio becomes the stoichiometric air-fuel ratio or rich, that is, when the oxygen concentration is lowered, storage carry out the absorption and release action of NO _X to release the NO _X. When this NO _x is absorbed and released, active oxygen is released, and this active oxygen can oxidize and remove particulates without generating a luminous flame. Therefore, if the NO _x catalyst device 6 is a particulate filter, The collected particulates are automatically oxidized and removed.

By the way, the NO _X catalyst device 6 cannot store NO _X without limitation, and the exhaust gas is exhausted before the NO _X storage amount of the NO _X catalyst device is saturated by using the NO _X releasing action. It is necessary to perform a regeneration process of the NO _x catalyst device that enriches the fuel ratio and releases the stored NO _x to reduce and purify it.

If the combustion air-fuel ratio is made rich or the fuel is injected into the cylinder in the expansion stroke or exhaust stroke in order to enrich the air-fuel ratio of the exhaust gas, a relatively large amount of particulates is included in the exhaust gas. Become. Thereby, in the present embodiment, in order to regenerate the NO _x catalyst device 6, the fuel supply device 4 is disposed on the upstream side of the turbine 1b in the engine exhaust passage 3, and the particulate fuel enters the exhaust gas. To supply.

However, even if particulate fuel is simply supplied into the exhaust gas, the reactivity of the particulate fuel is low with the exception of vaporized fuel that slightly evaporates, and it burns well using oxygen in the exhaust gas, nO _X catalyst device as 6 nO _X is released, it is not possible or favorably reduces and purifies the nO _X. Thereby, between the fuel supply device 4 and the NO _X catalyst device 6 (in the present embodiment, immediately upstream of the NO _X catalyst device 6 in the same casing), HC adsorbing oxidizer 5 is disposed, the fuel supply The particulate fuel supplied from the apparatus 4 is released as a highly reactive gaseous fuel by evaporation after being adsorbed by the HC adsorption / oxidation apparatus 5.

  The HC adsorption oxidizer 5 has a honeycomb structure formed of a material having a large specific surface area such as zeolite (for example, mordenite, which is a kind of zeolite), and has a plurality of partition walls extending in the axial direction. Has a number of axial spaces subdivided by. A noble metal catalyst such as platinum Pt is supported on both side surfaces of the partition walls and the inner surface of the pores.

The HC adsorption / oxidation apparatus 5 configured as described above adsorbs fine liquid fuel finely on the surface of each partition wall and in the pores, and gradually releases it as a gaseous fuel by evaporation. Although the gaseous fuel has a large number of carbon during evaporation, it is cracked by a noble metal catalyst and reformed to HC having a small number of carbon. The reformed gaseous HC is immediately oxidized by the noble metal catalyst by reacting with oxygen in the exhaust gas. The particulate fuel adsorbed by the HC adsorption / oxidation device in this way evaporates and reacts well with most of the oxygen in the exhaust gas to reduce the oxygen concentration in the exhaust gas and to reduce the gaseous concentration in the exhaust gas. It remains as HC. Thus, the exhaust gas oxygen concentration is lowered (e.g., 14.0 degree of the exhaust gas of a rich air-fuel ratio) when flows into NO _X catalyst device 6, NO _X is released from the NO _X catalyst device 6, it was released NO _x can be reduced and purified well by the gaseous HC remaining in the exhaust gas.

By the way, the amount of particulate fuel that can be adsorbed to the HC adsorption oxidizer 5 decreases as the temperature of the HC adsorption oxidizer 5 increases as shown in FIG. 2, and the HC adsorption oxidizer as shown in FIG. As the space velocity of the exhaust gas in 5, that is, the flow rate of the exhaust gas is faster, it becomes smaller. Even if supplied fuel exceeds the particulate fuel amount which can be adsorbed to the HC adsorbing oxidizer 5 by the fuel supply device 4, the fuel of this excess is, NO _X catalyst as less reactive particulate fuel It simply passes through the device 6 and worsens exhaust emissions.

  Thus, as shown in FIG. 4, the amount of fuel supplied from the fuel supply device 4 is set so as to substantially match the maximum adsorbable amount in the HC adsorption / oxidation device 5 for each engine operating state determined by the rotational speed and load. That is, at the time of low rotation and low load, since the exhaust gas temperature is low, the temperature of the HC adsorption oxidizer 5 becomes low, and the flow rate of the exhaust gas also becomes slow. On the other hand, when the engine speed is high and the load is high, the temperature of the HC adsorption oxidizer 5 is increased because the exhaust gas temperature is high, and the flow rate of the exhaust gas is also increased. If the supplied fuel amount set in this way is supplied into the exhaust gas in a very short time, the concentration of the particulate fuel in the exhaust gas flowing into the HC adsorption oxidizer 5 becomes very high, and the HC adsorption oxidation. In order to make it difficult to be adsorbed by the device 5, it is preferable to set the supply time of the supplied fuel amount so that the air-fuel ratio of the exhaust gas flowing into the HC adsorption / oxidation device 5 is in the range of approximately 1 to approximately 7.

Thus, during the regeneration process of the NO _x catalyst device 6, the amount of fuel supplied from the fuel supply device 4 is set for each engine operating state, so oxygen in the exhaust gas at the set supply fuel amount. It is possible to reduce and purify only the NO _x amount corresponding to the gaseous HC amount (HC amount remaining in the exhaust gas) other than that used for consumption. Namely, NO _X amount which can be reduced and purified by release from NO _X catalyst device 6 for each engine operating state becomes the same trend as the supply amount of fuel shown in FIG. 4, i.e., at low speed and low load, a relatively large amount of the nO _X to be able to be reduced and purified, whereas, at the time of high rotation and high load, a relatively small amount of the nO _X can only be reduced and purified. Thus, the amount of NO _{x that} can be reduced and purified in the regeneration process is set for each engine operating state, and the amount of fuel supplied for each engine operating state becomes the amount of fuel necessary for the regeneration process for each engine operating state.

FIG. 5 is a flowchart for carrying out the regeneration process of the NO _x catalyst device 6 in the exhaust purification device of the present embodiment. First, in step 101, emissions NOXA of the NO _X per unit in the current engine operating state time is calculated. The emission amount NOXA can be mapped in advance for each engine operating state, for example. Next, at step 102, the NO _X emission amount NOXA per unit time is integrated as the NO _X storage amount ΣNOX of the NO _X catalyst device 6.

Next, at step 103, the NO _X amount NX that can be reduced and purified in the current engine operating state is calculated. The NO _x amount NX is set as described above, and can be mapped in advance for each engine operating state, for example. In step 104, it is determined whether or not the NO _X storage amount ΣNOX has reached the NO _X amount NX that can be reduced and purified. If this determination is negative, the process ends. If YES, the NO _X catalyst device 6 is determined. Is the reproduction time, and the process proceeds to step 105.

In step 105, the accumulated time T during which the temperature of the HC adsorption oxidizer 5 is equal to or higher than the set temperature since the fuel supply device 4 supplied the fuel in the previous regeneration process is equal to or greater than the set accumulated time T1. It is determined whether or not. The temperature of the HC adsorbing oxidizer 5, may be monitored directly by placing the temperature sensor in the HC adsorbing oxidizer 5. Further, the temperature of the HC adsorbing oxidizer 5, may be estimated to based on the exhaust gas temperature flowing into the HC adsorbing oxidation device 5 is measured or estimated for each engine operating state, but in this case, playback processing When the fuel adsorbed in is evaporated and released, the HC adsorption oxidizer 5 burns using oxygen in the exhaust gas, so it is necessary to consider the temperature rise due to this combustion heat. When the determination in step 105 is affirmative, the temperature of the HC adsorption oxidizer 5 has been equal to or higher than the set temperature for at least the set integration time since the fuel supply device 4 supplied the fuel in the previous regeneration process. Therefore, it can be estimated that almost all of the fuel adsorbed in the previous regeneration process has been released, and the routine proceeds to step 108, where the supplied fuel amount set for the current engine operating state is determined as the current regeneration process. The fuel is supplied to the exhaust gas by the fuel supply device 4 as a necessary fuel amount.

Particulate fuel supplied in this way in order to be adsorbed to almost any HC adsorbing oxidizer 5, such that there is little to pass through the NO _X catalyst device 6 exist fuel that can not be adsorbed. However, when the determination in step 105 is negative, the temperature of the HC adsorption oxidizer 5 has not increased so much since the fuel supply device 4 supplied the fuel in the previous regeneration process, or the set temperature. Even if it increases above, it is a short time, and it is estimated that a part of the fuel adsorbed in the previous regeneration process remains. In this case, if the fuel supply device 4 supplies a fuel supply amount set so as to substantially match the maximum adsorbable amount of the HC adsorption oxidizer 5 in the current engine operating state, the HC adsorption oxidizer 5 remains. The fuel component to be absorbed cannot be adsorbed and passes through the NO _x catalyst device 6 as particulate fuel, thereby deteriorating the exhaust emission.

Thus, when the determination in step 105 is negative, in step 106, temperature increase control for increasing the temperature of the HC adsorption oxidizer 5 is performed, and the residual fuel in the HC adsorption oxidizer 5 is forcibly released. Fuel thus released is gaseous, burned using oxygen in the exhaust gas in the HC adsorbing oxidizer 5, it does not deteriorate the exhaust emission and passes through the NO _X catalyst device 6. As this temperature increase control, an electric heater 7 may be disposed in the HC adsorption oxidation apparatus 5 and the electric heater 7 may be operated. Further, an exhaust throttle valve is provided on the downstream side of the HC adsorption oxidizer 5, and the exhaust throttle valve is closed so that the heat of the exhaust gas is effectively used for raising the temperature of the HC adsorption oxidizer 5. Alternatively, post fuel injection may be performed by the fuel injection valve of the internal combustion engine to increase the temperature of exhaust gas discharged from the internal combustion engine. Such temperature rise control, by giving the same energy and to a higher set temperature in at least set integration time the temperature of the HC adsorbing oxidizer 5 to HC adsorbing oxidizer 5, the residual fuel in the HC adsorbing oxidizer 5 To release almost completely.

Next, at step 107, it is determined whether or not a set time has elapsed since the completion of the temperature raising control. After this determination is affirmed, fuel is supplied from the fuel supply device 4 in step 108. This set time is a temperature decrease period until the temperature of the HC adsorption oxidizer 5 heated by the temperature increase control decreases to a temperature corresponding to the current engine operating state before the temperature increase control. If the determination in step 107 is omitted and fuel is supplied by the fuel supply device 4 immediately after the temperature increase control is completed, the amount of fuel supplied by the fuel supply device 4 is increased by the HC adsorption / oxidation device 5 increased by the temperature increase control. must be reduced to an amount suitable temperature and, correspondingly, it must be reduced as well reduced can purify amount of nO _X NX that the threshold of the determination in step 104.

In step 105 of this flowchart, whether or not the temperature of the HC adsorption oxidizer 5 has been equal to or higher than the set temperature for at least the set integration time since the fuel supply device 4 supplied fuel in the previous regeneration process. However, the set integration time may be shortened as the temperature of the HC adsorption oxidizer 5 becomes higher than the set temperature.

Further, in this flowchart, the temperature increase control is performed only when the determination of step 105 is denied, but the determination of step 105 is omitted without measuring and estimating the temperature of the HC adsorption oxidizer, Temperature rise control is always performed during the period from when the particulate fuel is supplied by the fuel supply device 4 for the previous regeneration process to when the particulate fuel is supplied from the fuel supply device 4 for the current regeneration process. You may make it do. In the present embodiment, during the regeneration process of the NO _x catalyst device 6, the temperature rise control is performed and a subsequent temperature decrease period is provided, so that NO _x is further occluded in the NO _x catalyst device 6 during these periods. In view of this, the determination threshold value in step 104 may be decreased by a set amount from the NO _x amount NX that can be reduced and purified.

1 is a schematic view showing an exhaust gas purification apparatus for an internal combustion engine according to the present invention. It is a graph which shows the relationship between the temperature of HC adsorption oxidation apparatus, and the amount of particulate fuel which can be made to adsorb | suck to HC adsorption oxidation apparatus. It is a graph which shows the relationship between the space velocity in HC adsorption oxidation apparatus, and the amount of particulate fuel which can be made to adsorb | suck to HC adsorption oxidation apparatus. It is a map which shows the fuel supply amount set for every engine operation state. 3 is a flowchart for performing a regeneration process of a NO _x catalyst device.

Explanation of symbols

3 Exhaust passage 5 HC adsorption oxidation device 6 NO _X catalyst device 7 Electric heater

Claims (3)

NO _x catalyst device that occludes NO _x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and releases the occluded NO _x when the air-fuel ratio of the exhaust gas is the stoichiometric air-fuel ratio or rich, and the NO _x catalyst device of being placed in the exhaust upstream side of the exhaust gas and HC adsorption oxidizer having an oxidizing function while adsorbing hydrocarbons in an amount necessary for the reproducing process of reduction and purification by releasing NO _X from the NO _X catalyst device A fuel supply device for supplying particulate fuel to the HC adsorption oxidizer, and provided with residual fuel estimation means, and when it is determined that the residual fuel is present in the HC adsorption oxidizer during the current regeneration process only, it smells between the said fuel supply system for this regeneration process from the supply of the particulate fuel by the fuel supply device for the previous regeneration processing until the particulate fuel is supplied An exhaust purification device of an internal combustion engine which comprises carrying out temperature increase control for raising the temperature of the HC adsorbing oxidizer. NO _x catalyst device that occludes NO _x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and releases the occluded NO _x when the air-fuel ratio of the exhaust gas is the stoichiometric air-fuel ratio or rich, and the NO _x catalyst device of being placed in the exhaust upstream side of the exhaust gas and HC adsorption oxidizer having an oxidizing function while adsorbing hydrocarbons in an amount necessary for the reproducing process of reduction and purification by releasing NO _X from the NO _X catalyst device A fuel supply device for supplying particulate fuel to the HC adsorption / oxidation device, and the fuel for the current regeneration process after the particulate fuel is supplied by the fuel supply device for the previous regeneration process. Until the particulate fuel is supplied from the supply device, temperature increase control for increasing the temperature of the HC adsorption oxidation device is performed, and after the temperature increase control is performed, the fuel supply is performed in the current regeneration process. Between the device until the supply particulate fuel, exhaust gas purification apparatus for an internal combustion engine and providing a temperature drop period of the HC adsorbing oxidizer. During the period from the fuel supply device when the current reproduction process after the Atsushi Nobori control is carried out to supply a particulate fuel, in claim 1, characterized by providing a temperature drop period of the HC adsorbing oxidizer An exhaust gas purification apparatus for an internal combustion engine as described.

Images