JP2016094894A - Exhaust emission control system of internal combustion engine and exhaust emission control method of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control system and method of an internal combustion engine capable of preventing dischargement of a purification object component to atmosphere while corresponding to various situations.SOLUTION: An exhaust emission control system of an internal combustion engine includes: an exhaust flow passage 30 that is switched to a normal adsorption flow passage 31, a large amount adsorption flow passage 32, a desorption adsorption flow passage 33 and a vertical flow adsorption flow passage 34 in which combination and arrangement order of some of an exhaust emission control device 12, a first adsorption device 21 and a second adsorption device 22 are different; and a flow passage variable mechanism 40 that switches the exhaust flow passage 30 switched to the plurality of flow passages to a flow passage based on any of a purification situation of the exhaust emission control device 12, a reproduction situation and respective saturation situations of the first adsorption device 21 and second adsorption device 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas purification system for an internal combustion engine and an exhaust gas purification method for an internal combustion engine. More specifically, the present invention relates to an exhaust gas for an internal combustion engine that can prevent emission of components to be purified into the atmosphere while responding to various situations. The present invention relates to a purification system and an exhaust gas purification method for an internal combustion engine.

  In vehicles such as trucks equipped with diesel engines, exhaust gas purification devices that combine an oxidation catalyst (DOC), a collector (DPD), a urea-based selective reduction catalyst (SCR), an ammonia slip catalyst (ASC), etc. Purifying components to be purified such as nitrogen oxide (NOx), hydrocarbon (HC), carbon monoxide (CO), and ammonia as a reducing agent, contained in exhaust gas discharged from the engine.

  Furthermore, in addition to the exhaust gas purification device described above, an exhaust gas purification system has been proposed in which a device that adsorbs a purification target component is added (see, for example, Patent Document 1).

  In this exhaust gas purification system, an adsorbent that adsorbs hydrocarbons is arranged upstream of the oxidation catalyst, and until the oxidation catalyst is activated, the adsorbent adsorbs hydrocarbons in the exhaust gas, When activated, the hydrocarbon adsorbed on the adsorbent is desorbed and oxidized by the oxidation catalyst.

  However, in the exhaust gas purification system described above, only hydrocarbons among the purification target components that pass through the exhaust gas purification device at low temperatures are targeted, and other purification target components may be released to the atmosphere. The exhaust gas purification performance is insufficient.

  On the other hand, even if the adsorbent of the exhaust gas purification system described above is configured to adsorb other components to be purified, simply placing the adsorbent upstream of the oxidation catalyst will vary depending on the operating conditions of the engine and vehicle. It is not possible to cope with all of the purification status of the component to be purified in the changing exhaust gas purification device and the regeneration status of the exhaust gas purification device.

  For example, if the vehicle runs for a long time at a low load and the catalyst such as the oxidation catalyst or the selective catalytic reduction catalyst of the exhaust gas purification device is not sufficiently activated for a long time, the upstream of the exhaust gas purification device The amount of adsorption that can be adsorbed by the adsorbent disposed on the side exceeds the amount, and the purification target component may pass through the exhaust gas purification device.

  In addition, when hydrocarbons or carbon monoxide generated by soot combustion at the time of regeneration of the collection device of the exhaust gas purification device flows into the exhaust gas, the purification target component may be discharged as it is. .

In addition, while ammonia (NH ₃ ) serving as a reducing agent is supplied to purify nitrogen oxides with a selective reduction catalyst, ammonia as one of the components to be purified passes through the exhaust gas purification device. There is also a fear.

JP 2000-320324 A

  The present invention has been made in view of the above problems, and the problem is that an exhaust gas purification system for an internal combustion engine and an internal combustion engine that can prevent the release of components to be purified into the atmosphere while responding to various situations. An exhaust gas purification method is provided.

  An exhaust gas purification system for an internal combustion engine according to the present invention for solving the above-described problems is an exhaust gas for an internal combustion engine provided with an exhaust gas purification device for purifying a component to be purified contained in the exhaust gas discharged from the internal combustion engine. In the purification system, a plurality of adsorption devices having an adsorbent that adsorbs the purification target component at a low temperature and desorbs the adsorbed purification target component at a high temperature, and at least one of the adsorption downstream of the exhaust gas purification device A flow path in which an apparatus is disposed, an exhaust flow path that switches to a flow path in which at least one adsorption device is disposed upstream and downstream of the exhaust gas purification device, and the exhaust flow that switches to a plurality of flow paths A flow path for switching a path to a flow path based on any one of a purification status of the exhaust gas purification device, a regeneration status of the exhaust gas purification device, and a saturation status of the plurality of adsorption devices It is characterized in that it comprises a variable mechanism.

  Further, an exhaust gas purification method for an internal combustion engine according to the present invention for solving the above-described problem is an exhaust gas purification device disposed in an exhaust flow path, and a component to be purified contained in exhaust gas discharged from the internal combustion engine. An internal combustion system that purifies and further purifies with a plurality of adsorbent devices that are disposed in the exhaust flow path and have an adsorbent that adsorbs the purification target component at a low temperature and desorbs the adsorbed purification target component at a high temperature. An exhaust gas purification method for an engine, which is based on any one of a purification status of the exhaust gas purification device, a regeneration status of the exhaust gas purification device, and a saturation status of a plurality of the adsorption devices, Switch to a flow path in which at least one adsorption device is arranged downstream of the exhaust gas purification device, or to a flow channel in which at least one adsorption device is arranged upstream and downstream of the exhaust gas purification device. Thus, the purification target component that has passed through the exhaust gas purification device is adsorbed by at least one adsorption device, and the purification target component that has been desorbed from the adsorption device is purified by the exhaust gas purification device. And a method of purifying exhaust gas by combining at least one of the adsorption devices with the component to be purified before passing through the exhaust gas purification device or some combination thereof. It is.

  Here, the purification target component includes the hydrocarbons, carbon oxides, and nitrogen oxides contained in the exhaust gas and the reducing agent used in the exhaust gas purification device. Examples of the reducing agent include ammonia and hydrocarbons.

  According to the exhaust gas purification system for an internal combustion engine and the exhaust gas purification method for an internal combustion engine of the present invention, some combinations of the exhaust gas purification device and the plurality of adsorption devices, and the exhaust flow path that switches to a flow path having a different arrangement order Is switched to a flow path based on one of the purification status of the exhaust gas purification device, the regeneration status of the exhaust gas purification device, and the saturation status of the plurality of adsorption devices, so that it can be purified in accordance with each of various situations. The release of components into the atmosphere can be prevented.

  For example, when the oxidation catalyst or the selective reduction catalyst is not activated, the adsorption target component passing through the exhaust gas purification device is adsorbed by the adsorption device arranged downstream of the exhaust gas purification device, and the exhaust gas purification device Since the purification target component before passing through the exhaust gas purification device can be adsorbed by the adsorption device arranged upstream, it is possible to prevent the exhaust gas purification device from being poisoned by the purification target component.

  In addition, when the purification target component temporarily increases depending on the operating condition of the engine, a large amount of the purification target component that cannot be adsorbed by one adsorption device can be adsorbed by a plurality of adsorption devices.

  Also, when desorbing the component to be purified adsorbed from the adsorption device that is likely to saturate, the remaining adsorption device is exhausted even if the desorbing adsorption device is arranged upstream of the exhaust gas purification device. By disposing downstream of the gas purification device, the purification target component that has passed through the exhaust gas purification device can be adsorbed by the remaining adsorption device even while the purification target component is desorbed from the adsorption device.

1 is a schematic view illustrating an embodiment of an exhaust gas purification system for an internal combustion engine of the present invention, and illustrates a normal adsorption flow path. 1 is a schematic view illustrating an embodiment of an exhaust gas purification system for an internal combustion engine of the present invention, illustrating a large adsorption flow path. 1 is a schematic view illustrating an embodiment of an exhaust gas purification system for an internal combustion engine of the present invention, illustrating a desorption / adsorption channel. FIG. 1 is a schematic view illustrating an embodiment of an exhaust gas purification system for an internal combustion engine of the present invention, illustrating an upstream / downstream adsorption flow path. FIG. It is explanatory drawing which illustrates operation | movement of each flow-path switching valve at the time of switching each flow path shown in FIGS. 3 is a flowchart illustrating an embodiment of an exhaust gas purification method for an internal combustion engine of the present invention. It is a flowchart which illustrates the detail of step S30 of FIG.

  Hereinafter, embodiments of an exhaust gas purification system for an internal combustion engine and an exhaust gas purification method for an internal combustion engine according to the present invention will be described. In the following description, hydrocarbons, carbon oxides, nitrogen oxides, and ammonia will be described as components to be purified.

  1 to 4 show the configuration of an exhaust gas purification system 11 for an internal combustion engine according to an embodiment of the present invention. The exhaust gas purification system 11 is mounted on a diesel engine (hereinafter, engine) 10.

  The exhaust gas purification system 11 includes an exhaust gas purification device 12, and the exhaust gas purification device 12 includes an oxidation catalyst 13, a collection device 14, a urea water injection valve 15, an SCR catalyst 16, and ammonia in order from the upstream. A slip catalyst 17 is arranged.

  When the exhaust gas G exhausted from the engine 10 passes through the exhaust gas purification device 12 in a state where each catalyst is activated, in the oxidation catalyst 13, unburned hydrocarbons, carbon oxides contained in the exhaust gas, And nitrogen oxides are oxidized. Next, in the collection device 14, the nitrogen oxide is oxidized by the supported catalyst, and particulate matter contained in the exhaust gas is collected. Moreover, in this collection apparatus 14, a particulate matter is oxidized and removed by making the collected particulate matter and nitrogen dioxide react (henceforth passive regeneration). Next, in the SCR catalyst 16, nitrogen oxides are reduced by each SCR reaction using ammonia generated by hydrolysis of urea water injected from the urea water injection valve 15 as a reducing agent. Next, the ammonia that has passed through the SCR catalyst 16 is oxidized and removed by the ammonia slip catalyst 17.

  As described above, the exhaust gas purification device 12 oxidizes and reduces hydrocarbons, carbon oxides, nitrogen oxides, and ammonia as a reducing agent contained in the exhaust gas.

  Further, the exhaust gas purification device 12 needs to perform regeneration control periodically or when a large amount of particulate matter accumulates in the collection device 14 as the exhaust gas is purified. In the regeneration control of the exhaust gas purification device 12, post injection is performed by fuel injection control in the cylinder, or fuel is supplied to the exhaust gas, and the fuel is oxidized by the oxidation catalyst 13 temporarily. The exhaust gas temperature is increased. The high-temperature exhaust gas burns and removes the particulate matter deposited on the collection device 14 or burns and removes the white component of urea water deposited on the SCR catalyst 16.

  However, depending on the operating condition of the engine 10 and the running condition of the vehicle, the components to be purified pass through the exhaust gas purifying apparatus 12 without activating each catalyst of the exhaust gas purifying apparatus 12, or the exhaust gas purifying apparatus described above. During the regeneration control of 12, the purification target component that passes through the exhaust gas purification device 12 may temporarily increase.

  Therefore, in the exhaust gas purification system 11 of the present invention, the first adsorption device 21 and the second adsorption device 22, the exhaust passage 30 that switches to a plurality of passages, and the exhaust passage that switches to the plurality of passages. 30 is a flow path variable mechanism 40 that switches the flow path to a flow path based on one of the purification status and regeneration status of the exhaust gas purification device 12 and the saturation status of each of the first adsorption device 21 and the second adsorption device 22. It is prepared for.

  The material of the adsorbent 20 provided in the first adsorption device 21 and the second adsorption device 22 is a material that has a large surface area such as zeolite, clay mineral, porous silica, activated carbon, alumina, titania, zirconia, and is stable at high temperatures. A material carrying a component that increases the amount of adsorption of a component to be purified such as an alkali metal or alkaline earth metal oxide as a support, a zeolite ion-exchanged with a transition metal such as iron (Fe) or copper (Cu), and These mixtures and multilayers can be used.

  The first adsorbing device 21 and the second adsorbing device 22 are configured by coating the adsorbent 20 on a cordierite or silicon carbide (SiC) -based monolith or kneading into a carrier. When the temperature of the exhaust gas G passing through each of the first adsorbing device 21 and the second adsorbing device 22 is low, the adsorbent 20 adsorbs the purification target component and the purification target component including ammonia, When the temperature of the exhaust gas G is high, the purification target component adsorbed by the adsorbent 20 is desorbed. The temperature of the exhaust gas G at which the first adsorption device 21 and the second adsorption device 22 can adsorb the purification target component is, for example, 150 degrees or less, and the temperature of the exhaust gas G from which the adsorbed purification target component is desorbed. Is, for example, 250 degrees or more.

  The exhaust flow path 30 is provided in the flow path in which at least one of the first adsorption device 21 and the second adsorption device 22 is disposed downstream of the exhaust gas purification device 12 and upstream and downstream of the exhaust gas purification device 12, respectively. The flow is switched to the flow path in which each of the first adsorption device 21 and the second adsorption device 22 is arranged.

  1 to 4 show each of the flow paths in which the exhaust flow path 30 is switched. In FIG. 1, the first adsorption device 21 may be arranged instead of the second adsorption device 22, and the first adsorption device 21 is arranged upstream of the exhaust gas purification device 12 in the arrangement order of FIGS. 3 and 4. The second adsorption device 22 may be disposed downstream of the exhaust gas purification device 12.

  As shown in FIG. 1, the exhaust passage 30 is cut into a normal adsorption passage 31 in which a second adsorption device 22 that adsorbs a purification target component that has passed through the exhaust gas purification device 12 is disposed downstream of the exhaust gas purification device 12. Change.

  In addition, as shown in FIG. 2, the exhaust passage 30 includes a first adsorption device 21 and a second adsorption device 22 that adsorb the purification target component that has passed through the exhaust gas purification device 12 downstream of the exhaust gas purification device 12. It switches to the great adsorption flow path 32 arrange | positioned.

In addition, as shown in FIG. 3, the exhaust flow path 30 is provided with an adsorption device 22 from which the component to be purified adsorbed is desorbed upstream of the exhaust gas purification device 12 and exhaust gas downstream of the exhaust gas purification device 12. It switches to the desorption adsorption flow path 33 in which the first adsorption device 21 that adsorbs the component to be purified that has passed through the purification device 12 is arranged.

  In addition, as shown in FIG. 4, the exhaust flow path 30 includes an adsorption device 22 that adsorbs the purification target component before passing through the exhaust gas purification device 12 upstream of the exhaust gas purification device 12, and exhaust gas purification. The upstream / downstream adsorption flow path 34 in which the first adsorption device 21 that adsorbs the purification target component that has passed through the exhaust gas purification device 12 is disposed downstream of the device 12 is switched.

  The operation of the exhaust gas purification system 11 will be described. The exhaust gas purification method of the present invention by operating the exhaust gas purification system 11 is a flow in which several combinations of the exhaust gas purification device 12, the first adsorption device 21, and the second adsorption device 22 and their arrangement order are different. The exhaust flow path 30 that switches to the path is changed to those conditions based on the purification status and regeneration status of the exhaust gas purification device 12 and the saturation status of each of the first adsorption device 21 and the second adsorption device 22. This is a method of purifying the exhaust gas G by switching at appropriate times.

  Specifically, in the first situation where each catalyst such as the oxidation catalyst 13 and the SCR catalyst 16 is not activated, as shown in FIG. Switch to 34.

  By this upstream / downstream adsorption flow path 34, the low-temperature exhaust gas G is passed through the second adsorption device 22 and the exhaust gas purification device 12 in this order, and the purification target before passing through the exhaust gas purification device 12 by the second adsorption device 22 Adsorb components.

  Thereby, it is possible to prevent the exhaust gas purification device 12 from being poisoned by the component to be purified. Furthermore, in this upstream / downstream adsorption flow path 34, the remaining first adsorption device 21 is disposed downstream of the exhaust gas purification device 12, whereby the purification target component passing through the exhaust gas purification device 12 can be adsorbed. That is, in this first situation, the purification target components can be purified even in a situation where the adsorption devices are arranged both upstream and downstream of the exhaust gas purification device 12 and each catalyst is not activated.

  Further, although each catalyst of the exhaust gas purification device 12 has been activated to some extent, the exhaust gas is temporarily exhausted due to the second situation where the components to be purified cannot be sufficiently purified, the operating status of the engine 10 or the regeneration of the exhaust gas purification device 12. In the fourth situation where the purification target component passing through the purification device 12 increases, the flow path variable mechanism 40 switches the exhaust flow path 30 to the large adsorption flow path 32 as shown in FIG.

  By this great adsorption flow path 32, the exhaust gas G is passed in the order of the first adsorption device 21 and the second adsorption device 22 arranged in parallel with the exhaust gas purification device 12, and the plurality of first adsorption devices 21 and The second adsorption device 22 adsorbs more of the purification target component that has passed through the exhaust gas purification device 12 than the normal adsorption flow path 31. Thereby, the component to be purified that has passed through the exhaust gas purification device 12 and cannot be adsorbed by one adsorption device can be adsorbed by the plurality of adsorption devices of the first adsorption device 21 and the second adsorption device 22.

  In the case of the second situation and the fourth situation, the flow rate of the exhaust gas G that has passed through the exhaust gas purification device 12 may become large. However, by using the large adsorption flow path 32, the capacity capable of adsorbing the adsorbent 20 by the first adsorbing device 21 and the adsorbing device 22 arranged in parallel is doubled. Therefore, even if the flow rate of the exhaust gas G that has passed through the exhaust gas purification device 12 increases, the components to be purified can be adsorbed by both the first adsorption device 21 and the second adsorption device 22 in parallel and the pressure loss can be suppressed. .

Further, in the third situation in which the component to be purified adsorbed from the adsorption device 22 in which the adsorption amount may be saturated is desorbed, as shown in FIG. Switch to adsorption channel 33.

  The desorption / adsorption passage 33 allows the high-temperature exhaust gas G to pass through the second adsorption device 22 and the exhaust gas purification device 12 in this order, and the component to be purified desorbed from the second adsorption device 22 is exhausted. Purify with.

  Further, since the remaining first adsorption device 21 is disposed downstream of the exhaust gas purification device 12, the remaining first adsorption device 21 performs exhaust gas purification even while the component to be purified is desorbed from the second adsorption device 22. The component to be purified that has passed through the device 12 can be adsorbed.

  In other cases, the variable flow mechanism 40 switches the exhaust flow path 30 to the normal adsorption flow path 31 as shown in FIG. The normal adsorption flow path 31 allows the exhaust gas G to pass through the exhaust gas purification device 12 and the second adsorption device 22 in this order, and the second adsorption device 22 adsorbs the purification target component that has passed through the exhaust gas purification device 12.

  Thus, according to the exhaust gas purification system 11 and the exhaust gas purification method described above, some combinations of the exhaust gas purification device 12 and the first adsorption device 21 and the second adsorption device 22 as a plurality of adsorption devices. In addition, it is possible to prevent the purification target component from being released into the atmosphere by switching the exhaust flow path 30 that switches to a plurality of flow paths having different arrangement orders to a flow path according to various situations, and to purify the purification target component. It is possible to avoid the deterioration of the purification rate of the exhaust gas purification device 12 due to the above and the state where the first adsorption device 21 and the second adsorption device 22 are saturated and the component to be purified cannot be adsorbed.

  Further, by providing the first adsorption device 21 and the second adsorption device 22, the purification ability of the oxidation catalyst 13, the SCR catalyst 16, and the ammonia slip catalyst 17 of the exhaust gas purification device 12 is designed to be lower than that of the conventional catalyst. Therefore, the capacity of the oxidation catalyst 13, the SCR catalyst 16, and the ammonia slip catalyst 17 can be reduced and the amount of noble metal can be reduced, and the cost can be reduced.

  Next, details of the exhaust flow path 30 and the flow path variable mechanism 40 in the exhaust gas purification system 11 of the embodiment will be described.

  As shown in FIGS. 1 to 4, the exhaust passage 30 includes an upstream passage 35, a parallel passage 36, an introduction trident passage 37, and a lead-out trident passage 38.

  The upstream passage 35 is disposed upstream of the exhaust gas purification device 12.

  The parallel passage 36 is disposed downstream of the exhaust gas purification device 12, and includes an introduction passage 36a, a first passage 36b, a second passage 36c, and a lead-out passage 36d.

  The upstream end of the introduction passage 36 a is connected to the outlet of the exhaust gas purification device 12. The introduction passage 36a is preferably configured as a passage through which the exhaust gas G is sufficiently cooled while the exhaust gas G is passing therethrough. The temperature of the exhaust gas G after passing through the introduction passage 36a is preferably 150 ° C. or less.

  As a configuration for cooling the exhaust gas G passing through the introduction passage 36a, for example, the length of the pipe is sufficiently long, the surface is provided with an uneven shape, the surface area is increased, the layout is arranged so that the traveling wind is well applied, and the interior passes. For example, a heat exchanger for exchanging heat with the exhaust gas G to be cooled and a cooling device such as a cooling fan can be provided.

  In this way, by configuring the introduction passage 36a with a passage in which the exhaust gas G is sufficiently cooled while the exhaust gas G is passing, the first adsorption device 21 and the second adsorption device 22 are introduced from the introduction passage 36a. Since the temperature of the exhaust gas G flowing into the gas can be lowered, more components to be purified can be adsorbed to the first adsorption device 21 and the second adsorption device 22.

  In addition, the temperature of the exhaust gas G flowing into the exhaust gas G is low except when the purification target component adsorbed from the first adsorption device 21 and the second adsorption device 22 is desorbed, so that it is exposed to a relatively low temperature environment. In many cases, the first adsorbing device 21 and the second adsorbing device 22 are hardly deteriorated, which is advantageous for improving the durability.

  In the first passage 36b and the second passage 36c, the upstream end of the introduction passage 36a and the upstream end of the second passage 36c are respectively connected to the downstream end of the introduction passage 36a, and the downstream end of the introduction passage 36a and the second passage 36c. Are connected in parallel to each other by being connected to the upstream end of the lead-out passage 36d.

  The introduction trifurcation passage 37 has an upstream end connected to the first connection passage 37 a connected to the upstream passage 35, an upstream end connected to the downstream end of the first connection passage 37 a, and a downstream end downstream of the first adsorption device 21. A second connection passage 37b connected to the one passage 36b, and a third connection having an upstream end connected to the downstream end of the first connection passage 37a and a downstream end connected to the second passage 36c downstream of the second adsorption device 22. It is comprised by the connection channel | path 37c.

  The outlet trident passage 38 has an upstream end connected to the fourth connection passage 38 a connected to the upstream passage 35, an upstream end connected to the downstream end of the fourth connection passage 38 a, and a downstream end connected to the upstream of the first adsorption device 21. A fifth connection passage 38b connected to the one passage 36b, and a sixth connection passage whose upstream end is connected to the downstream end of the fourth connection passage 38a and whose downstream end is connected to the second passage 36c upstream of the second adsorption device 22. The connecting passage 38c is used. The fourth connection passage 38a is connected to the upstream passage 35 downstream of the first connection passage 37a.

  Each of the introduction trident passage 37 and the extraction trident passage 38 is preferably constituted by a passage in which the temperature of the exhaust gas G does not change while the exhaust gas G is passing, as compared with the introduction passage 36a. For example, the length of the pipe can be shortened sufficiently, the pipe can be made into a double pipe structure, or the layout can be prevented from being hit by the running wind.

  In this way, each of the introduction trident passage 37 and the extraction trident passage 38 is constituted by a passage in which the temperature of the exhaust gas G does not change while the exhaust gas G is passing, thereby allowing the high temperature exhaust gas G to pass therethrough. Then, when introduced into the first adsorption device 21 or the second adsorption device 22, the purification target component adsorbed by the first adsorption device 21 or the second adsorption device 22 can be efficiently desorbed and the high temperature thereof The exhaust gas G can be introduced into the exhaust gas purification device 12. On the other hand, when the low-temperature exhaust gas G is passed through and introduced into the first adsorption device 21 or the second adsorption device 22, more can be adsorbed.

  When the purification target component is desorbed from the first adsorption device 21 and the second adsorption device 22, the temperature of the exhaust gas G after passing through the introduction trident passage 37 is preferably 250 ° C. or more. When the component to be purified is adsorbed by the 21 and the second adsorption device 22, the temperature of the exhaust gas G after passing through the introduction trident passage 37 is preferably 150 degrees or less.

  Further, the second connection passage 37b and the third connection passage 37c are preferably diagonally-spiping pipes that are separated from the first passage 36b and the second passage 36c toward the downstream side, and the fifth connection passage 38b and the sixth connection passage. 38c is preferably a slanting pipe that is spaced upstream from the first passage 36b and the second passage 36c. With this configuration, when the exhaust gas G is introduced into the first passage 36b and the second passage 36c by the introduction trident passage 37, and when the exhaust gas G is introduced to the first passage 36b and the second passage 36c, the first passage 36b and the second passage 36b. When led out from the passage 36c, it can flow smoothly.

  The channel variable mechanism 40 includes a first channel switching valve 41, a second channel switching valve 42, a third channel switching valve 43, a fourth channel switching valve 44, a fifth channel switching valve 45, and their flow. It is comprised by the control apparatus 46 which controls a path switching valve.

  The first flow path switching valve 41 is formed by an on-off valve and is disposed between the branch point of the upstream passage 35 to the introduction trident passage 37 and the branch point from the lead-out trident passage 38. The first flow path switching valve 41 is opened when the normal adsorption flow path 31 and the large adsorption flow path 32 are selected, and opens the upstream passage 35. On the other hand, when the desorption adsorption channel 33 and the upstream / downstream adsorption channel 34 are selected, they are closed to block the upstream passage 35.

  The first flow path switching valve 41 flows into the first adsorption device 21 or the second adsorption device 22 by gradually closing from the opening direction to the closing direction when selecting the desorption adsorption flow channel 33. It is desirable to gradually warm the adsorbent 20 by gradually increasing the flow rate of the exhaust gas G. Thereby, when the flow of the exhaust gas G is suddenly switched, it is possible to prevent the high-concentration purification target component from being temporarily released due to the rapid heating of the adsorbent 20.

  The second flow path switching valve 42 is formed by a three-way valve, and is disposed at a branch point from the introduction path 36a of the parallel path 36 to the first path 36b and the second path 36c. The third flow path switching valve 43 is formed by a three-way valve and is disposed at a branch point from the first passage 36b and the second passage 36c to the outlet passage 36d. The second flow path switching valve 42 and the third flow path switching valve 43 are used when the normal adsorption flow path 31, the desorption adsorption flow path 33, and the upstream / downstream adsorption flow path 34 are selected. One of the two passages 36c is opened and the other is shut off. On the other hand, when selecting the large adsorption flow path 32, both the first passage 36b and the second passage 36c are opened.

  The fourth flow path switching valve 44 is formed by a three-way valve and is disposed at the branch point of the introduction trident passage 37. The fifth flow path switching valve 45 is formed by a three-way valve and is disposed at a branch point of the lead-out trident passage 38. The fourth flow path switching valve 44 and the fifth flow path switching valve 45 are closed when the normal adsorption flow path 31 and the large adsorption flow path 32 are selected, and the introduction trident passage 37 and the discharge trident passage 38 are blocked. On the other hand, it opens when selecting the desorption adsorption channel 33 and the upstream / downstream adsorption channel 34, opens one of the second connection passage 37b and the third connection passage 37c and shuts off the other. One of the connection passage 38b and the sixth connection passage 38c is opened and the other is shut off.

  FIG. 5 shows the operation of each flow path switching valve when the normal adsorption flow path 31, the large adsorption flow path 32, the desorption adsorption flow path 33, and the upstream / downstream adsorption flow path 34 are selected.

  The control device 46 controls each of the above-described flow path switching valves based on one of the purification status and the regeneration status of the exhaust gas purification device 12 and the saturation status of the first adsorption device 21 and the second adsorption device 22. It is a microcontroller. The control device 46 may be incorporated in an overall system control device that performs overall control of the engine 10 based on information from various sensors such as an accelerator opening sensor (not shown), or may be provided independently. The control device 46 also performs the control of the urea water injection valve 15 and the regeneration control of the exhaust gas purification device 12 described above.

Further, the control device 46 has means for estimating the temperature T1 of the exhaust gas passing through the upstream passage 35 as device inlet temperature acquisition means. This temperature T1 is the operating state of the engine 10,
That is, the temperature is estimated based on the fuel injection amount and the intake air amount injected into the cylinder of the engine 10, and a temperature estimation map created in advance by experiments and tests in the control device 46 is used for the estimation. The temperature T1 may be acquired by a temperature sensor disposed at any location in the upstream passage 35, preferably upstream of the first flow path switching valve 41.

  In addition, the control device 46 is disposed downstream of the collection device 14 of the exhaust gas purification device 12 and upstream of the SCR catalyst 16 as catalyst inlet temperature acquisition means, and the temperature of the exhaust gas passing through the disposed portion. It is connected to a temperature sensor 47 that acquires T2.

Furthermore, the control device 46, as the passing amount obtaining means, disposed in the introduction passage 36a of the parallel passage 36, the nitrogen oxides to obtain the NOx concentration [rho _NOx contained in the exhaust gas passing through the deployed position The concentration sensor 48 is connected to each of an ammonia concentration sensor 49 that acquires the ammonia concentration _ρNH3 . The detected values of the nitrogen oxide concentration sensor 48 and the ammonia concentration sensor 49 are used for determination of the urea water injection amount injected from the urea water injection valve 15 in the exhaust gas purification device 12, and the first adsorption. The accumulation state of the component to be purified in the adsorbent 20 of the apparatus 21 and the second adsorption apparatus 22 is also estimated. These concentration sensors are preferably arranged in the introduction passage 36a, but may be arranged in the lead-out passage 36d.

  Next, details of the exhaust gas purification method of the engine 10 of the embodiment will be described with reference to the flowchart shown in FIG.

  Further, in this exhaust gas purification method, each determination in step S10 to step S40 is performed to determine the purification status and regeneration status of the exhaust gas purification device 12, and the saturation status of the first adsorption device 21 and the second adsorption device 22. Thus, the optimum flow path is selected from the exhaust flow paths 30 that can be switched to a large number of flow paths based on each situation.

  When starting, in Step S10, it is determined whether or not the temperature T1 estimated by the control device 46 is equal to or higher than a predetermined first threshold Ta. The first threshold Ta is set to a value that can determine whether or not each catalyst of the exhaust gas purification device 12 is activated, and is preferably set to a value of 100 degrees or more and 250 degrees or less, more preferably 200 degrees. The

  If the temperature T1 is lower than the first threshold value Ta in step S10, the control device 46 determines that the exhaust gas purification device 12 has not been activated in accordance with the situation where each catalyst of the exhaust gas purification device 12 is not activated, that is, the component to be purified. It is determined that the first situation in which there is a risk of poisoning and the purification target component passing through the exhaust gas purification device 12 increases, and the process proceeds to step 50.

  Next, in step S50, the control device 46 selects the upstream / downstream adsorption flow path 34. When the upstream / downstream adsorption flow path 34 is selected in step S50, the control device 46 controls each flow path switching valve to switch the exhaust flow path 30 to the upstream / downstream adsorption flow path 34.

  The upstream / downstream adsorption flow path 34 adsorbs the purification target component contained in the low-temperature exhaust gas G before passing through the exhaust gas purification device 12 by the second adsorption device 22, and the first adsorption device 21 exhausts the exhaust gas. The component to be purified after passing through the purification device 12 is adsorbed. In other words, the purification target component is prevented from being released into the atmosphere during low temperature startup of the engine 10 or during long-term low load operation, and the exhaust gas purification device 12 is prevented from being poisoned by the purification target component.

If the temperature T1 is equal to or higher than the first threshold Ta in step S10, the process proceeds to step S20. Next, in step S20, it is determined whether or not the temperature T2 acquired by the control device 46 from the temperature sensor 47 is equal to or higher than a predetermined second threshold value Tb. The second threshold value Tb is set to a value that can determine whether or not the urea water is sufficiently hydrolyzed when the urea water is injected from the urea water injection valve 15, and is preferably 170 degrees or more and 250 degrees. The following value is set, more preferably 200 degrees.

  In this step S20, when the temperature T2 is lower than the second threshold value Tb, the control device 46 has activated the oxidation catalyst 13 on the upstream side of the exhaust gas purification device 12, but even if the urea water is injected. Then, it is determined that the urea water is not sufficiently activated, that is, the second situation in which the exhaust gas purification device 12 cannot sufficiently purify the purification target component, and the process proceeds to step 60.

  Next, in step S <b> 60, the control device 46 selects the large adsorption flow path 32. When the large adsorption flow path 32 is selected in step S60, the control device 46 controls each flow path switching valve to switch the exhaust flow path 30 to the large adsorption flow path 32.

  By this great adsorption flow path 32, the purification target components contained in the high-temperature exhaust gas G that has passed through the exhaust gas purification device 12 by the plurality of first adsorption devices 21 and the second adsorption devices 22 are reliably adsorbed. That is, the release of the purification target component to the atmosphere when the engine 10 suddenly becomes a transient state is prevented.

  If the temperature T2 is equal to or higher than the second threshold value Tb in step S20, the process proceeds to step S30. Next, in step S30, the control device 46 determines whether or not the condition A is satisfied. A condition for satisfying this condition A is that one of the first adsorption device 21 and the second adsorption device 22 is desorbed.

  In step S30, if the condition A is satisfied, that is, if either the first adsorption device 21 or the second adsorption device 22 is desorbed, the control device 46 performs the first adsorption device 21 or the second adsorption. It is determined that one of the devices 22 may be saturated, that is, the third situation, and the process proceeds to step 70.

  Next, in step S <b> 70, the control device 46 selects the desorption / adsorption channel 33. When the desorption / adsorption channel 33 is selected in step S <b> 70, the control device 46 controls each channel switching valve to switch the exhaust channel 30 to the desorption / adsorption channel 33.

  The desorption / adsorption channel 33 desorbs the purification target component adsorbed when the high-temperature exhaust gas G passes through the second adsorption device 22 disposed upstream of the exhaust gas purification device 12. Then, the desorbed purification target component can be purified by the exhaust gas purification device 12. Furthermore, the purification target component that has passed through the exhaust gas purification device 12 can be adsorbed by the remaining first adsorption device 21 even while the purification target component is desorbed from the second adsorption device 22.

If the condition A is not satisfied in step S30, the process proceeds to step S40. Next, in step S40, the control device 46 determines whether or not the condition B is satisfied. This condition B is met when the exhaust gas purifying device 12 is regenerating, or when the nitrogen oxide concentration ρ _NOx detected by the nitrogen oxide concentration sensor 48 is equal to or higher than a predetermined third threshold ρa, or ammonia is the fourth threshold value ρb than the ammonia concentration [rho _NH3 is detected values of the density sensor 49 is predetermined.

  The third threshold ρa is set to a value that can determine that the amount of nitrogen oxide passing through the exhaust gas purification device 12 is large. The fourth threshold ρb is set to a value that can determine that the amount of ammonia passing through the exhaust gas purification device 12 is large.

When the condition B is satisfied in step S50, the control device 46 may temporarily increase the purification target component with the regeneration of the exhaust gas purification device 12, or the exhaust gas purification device 12 It determines with the 4th condition where the purification | cleaning condition in is worsening, and progresses to step 60. FIG.

  When the condition B is established in step S40, when the exhaust gas purification device 12 is regenerated, carbon monoxide and exhaust gas generated by carbonization and soot combustion supplied to the exhaust gas by post injection or the like. As the temperature rises, ammonia desorbed from the SCR catalyst 16 may pass through the exhaust gas purification device 12. Moreover, there is a possibility that the purification target component that has passed through the exhaust gas purification device 12 is released to the atmosphere. However, in such a case, in step S60, the control device 46 controls each flow rate switching valve to switch the exhaust passage 30 to the large adsorption passage 32, and a plurality of downstream portions of the exhaust gas purification device 12 are placed. By arranging the first adsorption device 21 and the second adsorption device 22, even if the flow rate of the exhaust gas that has passed through the exhaust gas purification device 12 increases, the components to be purified can be purified by both the adsorption device 21 and the adsorption device 22. Can be adsorbed.

  On the other hand, if the condition B is not satisfied in step S40, the process proceeds to step S80. Next, in step S80, the control device 46 selects the normal adsorption channel 31. When the normal adsorption channel 31 is selected in step S80, the control device 46 controls each channel switching valve to switch the exhaust channel 30 to the normal adsorption channel 31.

  By means of this normal adsorption flow path 31, most of the purification target component is purified by the exhaust gas purification device 12, and the purification target component that cannot be completely purified or desorbed is adsorbed by the second adsorption device 22.

  When Step S50 to Step S80 are performed and an optimum flow path is selected from the exhaust flow path 30, the process returns to the start, and the determinations of Step S10 to Step S40 are sequentially started again.

  According to the exhaust gas purification method described above, the purification status and regeneration status of the purification target component of the exhaust gas purification device 12 and the adsorption of the first adsorption device 21 and the second adsorption device 22 based on the determinations in steps S10 to S40. By determining the situation and selecting the optimum flow path according to the situation from the exhaust flow path 30, it is possible to prevent the component to be purified from being released into the atmosphere and to poison the exhaust gas purification device 12. In addition, saturation of the first adsorption device 21 and the second adsorption device 22 can also be prevented. Thereby, purification of the purification target component contained in the exhaust gas in the exhaust gas purification system 11 can be improved.

  Details of the conditions for establishing condition A in step S30 are shown in the flowchart of FIG. In addition, although the determination of the 2nd adsorption | suction apparatus 22 is illustrated here, it determines similarly about the 1st adsorption | suction apparatus 21. FIG.

  This determination method performs each determination of step S100 and step S110, discriminates the adsorption state of the second adsorption device 22, and desorbs the purification target component adsorbed from the second adsorption device 22 based on the situation. This is a method for determining whether or not.

  First, in step S100, it is determined whether or not the operation time Δt1 after the control device 46 desorbs the purification target component adsorbed from the second adsorption device 22 is equal to or greater than the fifth threshold value Δta. The fifth threshold value Δta is set to a time during which it is necessary to desorb the purification target component adsorbed from the second adsorption device 22 measured in advance by experiments and tests. In step S100, it may be determined whether the travel distance is equal to or greater than a predetermined threshold by using the travel distance after desorption instead of the operation time Δt1.

If the operation time Δt1 is greater than or equal to the fifth threshold value Δta in step S100, the process proceeds to step S110. Next, in step S <b> 110, the control device 46 determines that the purification target component is desorbed from the second adsorption device 22.

On the other hand, if the operation time Δt1 is less than the fifth threshold value Δta in step S100, the process proceeds to step S110. Next, in step S110, the control device 46 determines whether or not the condition C is satisfied. The conditions for satisfying this condition C are that the hydrocarbon adsorption amount A _HC , the carbon monoxide adsorption amount A _CO , the nitrogen oxide adsorption amount A _NOx , and the ammonia adsorption amount A _NH3 are predetermined threshold values. Or the total adsorption amount A _{total of the} hydrocarbon adsorption amount A _HC , carbon monoxide adsorption amount A _CO , nitrogen oxide adsorption amount A _NOx , and ammonia adsorption amount A _NH3. Is greater than or equal to a threshold value. Here, each threshold value is set to a value smaller than the upper limit value of the adsorption amount that can be adsorbed by the second adsorption device 22 measured in advance by experiments or tests. Thus, setting each threshold value to a value smaller than the upper limit value is advantageous in avoiding saturation.

The adsorption amount A _HC is estimated from the following formula (1) based on the accumulated adsorption time in which the purification target component is adsorbed in each flow channel after the adsorption target component adsorbed last time is desorbed. Here, the accumulated adsorption time for adsorbing the purification target component downstream of the exhaust gas purification device 12 in the normal adsorption channel 31, the desorption adsorption channel 33, and the upstream / downstream adsorption channel 34 is Δt 2, and the large adsorption channel 32. Is the integrated use time at Δt3, the integrated adsorption time at which the purification target component is adsorbed upstream of the exhaust gas purification device 12 in the upstream / downstream adsorption flow path 34 is Δt4, and x, y, and z are coefficients. The coefficients x, y, and z are coefficients based on the combustion state of the fuel in the engine 10 and the purification status of the exhaust gas purification device 12. x may be a constant of a typical adsorption amount per unit time downstream of the exhaust gas purification device 12 in the normal adsorption channel 31, desorption adsorption channel 33, and upstream / downstream adsorption channel 34, or engine operation. It may be handled as a numerical value related to the situation or the purification status of the exhaust gas purification device 12. y may be a constant of a typical adsorption amount per unit time in the large adsorption flow path 32, or may be handled as a numerical value related to the operation state of the engine or the purification state of the exhaust gas purification device 12. z may be a constant of a typical adsorption amount per unit time upstream of the exhaust gas purification device 12 in the upstream / downstream adsorption flow path 34, and is related to the engine operating status and the purification status of the exhaust gas purification device 12. It may be handled as a numerical value.

The adsorption amount _ACO is estimated from the following formula (2) based on the integrated adsorption time in which the purification target component is adsorbed in each flow channel after the adsorption target component adsorbed last time is desorbed.

The adsorption amount A _NOx is estimated from the following formula (3) based on the accumulated adsorption time in which the purification target component is adsorbed in each flow channel after the adsorption target component adsorbed last time is desorbed. Here, the total time of the time Δt2 and the time Δt3 is Δt, the detected value of the nitrogen oxide concentration sensor 48 is w, the flow rate of the exhaust gas is Q, and the coefficient is α. The coefficient α represents the adsorption rate of the nitrogen oxides in the exhaust gas with respect to the first adsorption device 21 and the second adsorption device 22. The adsorption rate can be expressed as a constant or as a function of the temperature of the first adsorption device 21 and the second adsorption device 22. The exhaust gas flow rate Q is calculated based on, for example, the fuel injection amount and the intake air amount in the engine 10.

The adsorption amount A _NH3 is estimated from the following formula (4) based on the integrated adsorption time in which the purification target component is adsorbed in each flow channel after the adsorption target component adsorbed last time is desorbed. Here, the detection value of the ammonia concentration sensor 49 is v, and the coefficient is β. The coefficient β represents the adsorption rate of ammonia in the exhaust gas with respect to the first adsorption device 21 and the second adsorption device 22.

  If the condition C is satisfied in step S110, the process proceeds to step S120. On the other hand, if the condition D is not satisfied in step S110, the process proceeds to step S130. Next, in step S130, the control device 46 determines not to desorb the purification target component from the second adsorption device 22.

  In this way, the purification target component adsorbed from the second adsorption device 22 based on the operation time Δt1 from the previous desorption of the purification target component and the adsorption amount of the purification target component adsorbed on the second adsorption device 22. By determining whether or not to desorb the component, it is possible to avoid a state in which the second adsorption device 22 reaches a saturation amount and cannot adsorb the purification target component. The same applies to the first adsorption device 21.

  In the exhaust gas purification system 11 described above, the flow path variable mechanism 40 includes the adsorption amount A1 of the purification target component adsorbed by the first adsorption device 21 and the second adsorption device 22 from the plurality of exhaust flow paths 30. A configuration is preferable in which the flow path is selected so that the adsorption amount A2 of the adsorbed purification target component is different. In this embodiment, the case where the amount of adsorption A2 is larger than the amount of adsorption A1 is described as an example. In the normal adsorption channel 31, the second adsorption device 22 is arranged downstream of the exhaust gas purification device 12. In the upstream / downstream adsorption flow path 34, the second adsorption device 22 is arranged upstream of the exhaust gas purification device 12.

  Specifically, in the flowchart shown in FIG. 6, when step S10 is not established, a step of determining whether or not the adsorption amount A1 is less than the adsorption amount A2 is performed. Similarly, when step S60 is not established, a step of determining whether or not the adsorption amount A1 is less than the adsorption amount A2 is performed. In these steps, when the adsorption amount A1 is less than the adsorption amount A2, the second adsorption device 22 is selected as the adsorption device arranged upstream of the exhaust gas purification device 12, while the adsorption amount A1 is When the adsorption amount is A2 or more, the first adsorption device 21 is selected as the adsorption device arranged upstream of the exhaust gas purification device 12.

  Thus, the flow path is selected so that the adsorption amount A1 and the adsorption amount A2 are always different, that is, the flow path is selected so that one of the adsorption amount A1 and the adsorption amount A2 is always larger than the other. Thereby, it can avoid that both the 1st adsorption | suction apparatus 21 and the 2nd adsorption | suction apparatus 22 are saturated simultaneously. This avoids a state in which neither the first adsorption device 21 nor the second adsorption device 22 can adsorb the purification target component, which is advantageous for improving the purification rate in the exhaust gas purification system 11.

In addition, although said engine 10 demonstrated the diesel engine to the example, this invention is not limited to this, For example, it can apply also to a gasoline engine.

  Further, the configuration of the exhaust gas purification device 12 is not limited to the above-described configuration, but a lean NOx reduction catalyst (LNT) such as a NOx storage reduction catalyst (NSR), an oxidation catalyst 13, a collection device 14, a urea system SCR catalyst 16, an SCR catalyst device using HC as a reducing agent (HC-SCR), an ammonia slip catalyst 17, and a catalyst device having a combined function (for example, a combined device of a particulate collection device and a selective reduction catalyst device) Or a combination of any of the selective catalyzed combustion filters (SCRFs).

  Moreover, although said 1st adsorption apparatus 21 and said 2nd adsorption apparatus 22 were demonstrated as a structure which adsorb | sucks hydrocarbon, carbon oxide, nitrogen oxide, and ammonia, it is not limited to this, Exhaust gas purification | cleaning The components that can be adsorbed can be changed by the configuration of the device 12 and the change in the components contained in the exhaust gas discharged from the engine 10.

  Further, the number of adsorption devices is not limited to two, and two or more adsorption devices may be provided. In that case, the number of passages constituting the exhaust flow path 30 may be increased according to the number of adsorption devices.

DESCRIPTION OF SYMBOLS 10 Engine 11 Exhaust-gas purification system 12 Exhaust-gas purification apparatus 20 Adsorbents 21 and 22 First adsorption apparatus, 2nd adsorption apparatus 30 Exhaust flow path 31 Normal adsorption apparatus 32 Large adsorption flow path 33 Desorption adsorption flow path 34 Upstream / downstream adsorption Channel 40 Channel variable mechanism

Claims (8)

In an exhaust gas purification system for an internal combustion engine provided with an exhaust gas purification device for purifying a purification target component contained in exhaust gas discharged from the internal combustion engine,
A plurality of adsorption devices having an adsorbent that adsorbs the purification target component at a low temperature and desorbs the adsorbed purification target component at a high temperature;
Exhaust flow switching to a flow path in which at least one adsorbing device is disposed downstream of the exhaust gas purifying device, and a flow path in which at least one adsorbing device is disposed upstream and downstream of the exhaust gas purifying device. Road,
The exhaust flow path that switches to a plurality of flow paths is switched to a flow path based on any one of the purification status of the exhaust gas purification device, the regeneration status of the exhaust gas purification device, and the saturation status of the plurality of adsorption devices. An exhaust gas purification system for an internal combustion engine, comprising: a flow path variable mechanism. The flow path variable mechanism, the exhaust flow path,
A normal adsorption flow path in which at least one adsorption device that adsorbs the purification target component that has passed through the exhaust gas purification device is disposed downstream of the exhaust gas purification device;
A large adsorption flow path in which a larger number of the adsorption devices than the normal adsorption flow channel that adsorbs the purification target component that has passed through the exhaust gas purification device are disposed downstream of the exhaust gas purification device,
The at least one adsorption device that desorbs the adsorbed component to be purified is disposed upstream of the exhaust gas purification device, and the purification target component that has passed through the exhaust gas purification device downstream of the exhaust gas purification device A desorption adsorption channel in which at least one adsorption device for adsorbing is arranged,
And at least one adsorbing device that adsorbs the component to be purified before passing through the exhaust gas purifying device is disposed upstream of the exhaust gas purifying device, and the exhaust gas is disposed downstream of the exhaust gas purifying device. The exhaust gas purification system for an internal combustion engine according to claim 1, wherein the exhaust gas purification system is configured to be switched to one of upstream and downstream adsorption flow paths in which at least one adsorption device that adsorbs the purification target component that has passed through the purification device is disposed. The flow path variable mechanism is
In the case of the first situation where the exhaust gas inlet temperature of the exhaust gas passing through the exhaust gas purifier inlet is less than a predetermined first threshold, the exhaust flow path is switched to the upstream / downstream adsorption flow path,
In the case of a second situation other than the first situation where the catalyst inlet temperature of the exhaust gas passing through the catalyst inlet of the exhaust gas purification device is less than a predetermined second threshold, the exhaust flow path is Switch to the great adsorption flow path,
In the third situation where the condition for desorbing the purification target component from at least one of the adsorption devices is established except for the first situation and the second situation, the exhaust flow path is removed from the desorption passage. Switch to adsorption flow path,
In the case of the fourth situation in which the condition for increasing the purification target component passing through the exhaust gas purification device other than the first situation, the second situation, and the third situation is satisfied, Switch the exhaust passage to the large adsorption passage,
3. An exhaust gas purification system for an internal combustion engine according to claim 2, wherein the exhaust passage is switched to the normal adsorption passage in cases other than the above. Two of the first adsorption device and the second adsorption device as the plurality of adsorption devices,
The exhaust passage includes an upstream passage disposed upstream of the exhaust gas purification device, a parallel passage disposed downstream of the exhaust gas purification device, and an introduction trifurcation connecting the upstream passage and the parallel passage. It consists of a passage and a lead-out trident passage,
An introduction passage having an upstream end connected to an outlet of the exhaust gas purification device; a first passage having an upstream end connected to the downstream end of the introduction passage and the first adsorption device disposed; ,
The upstream end is connected to the downstream end of the introduction passage, the upstream end is connected to the downstream end of the first passage and the downstream end of the second passage. The outlet passage and the first passage and the second passage are arranged in parallel,
The introduction trifurcated passage, the first connection passage whose upstream end is connected to the upstream passage, the second connection passage and the third connection passage whose upstream end is connected to the downstream end of the first connection passage, The downstream end of the second connection passage is connected to the first passage downstream of the first adsorption device, and the downstream end of the third connection passage is connected to the second passage downstream of the second adsorption device. Configure
The derivation three-way passage, a fourth connection passage whose upstream end is connected to the upstream passage downstream of the first connection passage, and a fifth connection whose upstream end is connected to the downstream end of the fourth connection passage The downstream end of the fifth connection passage is connected to the first passage upstream of the first adsorption device by the passage and the sixth connection passage, and the downstream end of the sixth connection passage is connected upstream of the second adsorption device. Connected to the second passage of
The flow path variable mechanism includes a first flow path switching valve disposed in the upstream passage between the introduction trident passage and the extraction trident passage, four of the parallel passage, the introduction trident passage, and the extraction trident passage. A second flow path switching valve, a third flow path switching valve, a fourth flow path switching valve, and a fifth flow path switching valve respectively disposed at one branch point, and a control device that controls the respective flow path switching valves; The exhaust gas purification system for an internal combustion engine according to any one of claims 1 to 3, comprising:   The exhaust gas purification system for an internal combustion engine according to claim 4, wherein the introduction passage of the parallel passage is configured by a passage for cooling the exhaust gas passing through the introduction passage.   At least one adsorbing device for desorbing the adsorbed component to be purified is disposed in the exhaust passage upstream of the exhaust gas purifying device, and the exhaust gas purifying device is disposed downstream of the exhaust gas purifying device. When switching to the desorption adsorption flow path in which at least one adsorption device for adsorbing the component to be purified that has passed is disposed, the first flow path switching valve is configured to be gradually closed from the opening direction to the closing direction. Item 6. An exhaust gas purification system for an internal combustion engine according to Item 4 or 5.   The flow path variable mechanism is configured to switch the exhaust flow path that switches to a plurality of flow paths to a flow path that makes the amount of adsorption of the purification target component of each of the plurality of adsorption devices different. The exhaust gas purification system for an internal combustion engine according to any one of -6. The exhaust gas purification device disposed in the exhaust flow path purifies the purification target component contained in the exhaust gas discharged from the internal combustion engine, and is disposed in the exhaust flow path to adsorb the purification target component at a low temperature. An exhaust gas purification method for an internal combustion engine that further purifies with a plurality of adsorption devices having an adsorbent that desorbs the adsorbed component to be purified at a high temperature,
Based on the purification status of the exhaust gas purification device, the regeneration status of the exhaust gas purification device, and the saturation status of the plurality of adsorption devices, at least one of the exhaust flow paths is provided downstream of the exhaust gas purification device. By switching to a flow path in which one of the adsorption devices is disposed, or a flow path in which at least one of the adsorption devices is disposed upstream and downstream of the exhaust gas purification device,
Adsorbing the purification target component that has passed through the exhaust gas purification device with at least one adsorption device; and purifying the purification target component desorbed from the adsorption device with the exhaust gas purification device; and An exhaust gas for an internal combustion engine, wherein exhaust gas is purified by any one or a combination of adsorbing the purification target component before passing through the exhaust gas purification device by at least one of the adsorption devices Purification method.

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