JP2013119771A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the purification efficiency of exhaust gas by an SCR catalyst by not only a composition of nitrogen oxides included in the exhaust gas but also "the temperature of the SCR catalyst".SOLUTION: This exhaust emission control device includes an exhaust temperature adjusting means arranged in an exhaust passage of an internal combustion engine and adjusting the temperature of the exhaust gas exhausted from a combustion chamber of the internal combustion engine, and the catalyst arranged in a downstream side position rather than the exhaust temperature adjusting means in the exhaust passage and purifying the exhaust gas. The exhaust emission control device is constituted so that at least a part of the exhaust gas passing through the exhaust temperature adjusting means can be introduced into the catalyst as first exhaust gas after passing through at least a part of an intermediate member arranged in a position between the exhaust temperature adjusting means and the catalyst in the exhaust passage, and at least a part of the exhaust gas passing through the exhaust temperature adjusting means can be introduced into the catalyst as second exhaust gas without passing through at least the part of the intermediate member.

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine provided with a catalyst for purifying exhaust gas of the internal combustion engine in an exhaust passage.

  Gas (exhaust gas) discharged from a combustion chamber of an internal combustion engine generally includes various substances such as nitrogen oxide (NOx) and particulate matter (PM). It is desirable to reduce the discharge amount of these substances to the outside of the internal combustion engine as much as possible. Therefore, conventionally, an exhaust emission control device that purifies exhaust gas by removing these substances from the exhaust gas has been proposed.

  For example, conventionally, a catalyst that purifies exhaust gas by selectively reducing specific components contained in exhaust gas (a so-called selective catalytic reduction catalyst; hereinafter also referred to as “SCR catalyst”) is provided in the exhaust passage. Exhaust gas purification devices have been proposed. As this type of exhaust purification device, for example, an SCR catalyst that selectively removes (reduces) nitrogen oxides (NOx) contained in exhaust gas is provided, and a reducing agent (for example, urea) is contained in the exhaust gas introduced into the catalyst. Exhaust gas purification devices that supply water) can be mentioned. In this exhaust purification device, nitrogen oxides contained in the exhaust gas in the SCR catalyst are reacted with a reducing agent (for example, ammonia obtained by hydrolysis of urea in urea water), whereby nitrogen oxides are formed. It is removed from the exhaust (nitrogen oxides are reduced to nitrogen and water).

  One of the conventional exhaust purification devices having the SCR catalyst (hereinafter also referred to as “conventional device”) is used for exhaust introduced into the SCR catalyst in order to remove nitrogen oxide from the exhaust as efficiently as possible. The composition of the nitrogen oxide contained (molar ratio of nitric oxide and nitrogen dioxide) is adjusted.

  Specifically, the conventional apparatus includes an electric heater, an oxidation catalyst that converts nitric oxide into nitrogen dioxide (the conversion rate from nitrogen monoxide to nitrogen dioxide depends on the temperature of the oxidation catalyst), and particulate form. A diesel particulate filter (hereinafter also referred to as “DPF”) for collecting substances, a nozzle for supplying urea water as a reducing agent into the exhaust, and an SCR catalyst are provided in this order on the exhaust passage. . The conventional apparatus adjusts the temperature of the oxidation catalyst by changing the amount of heat generated by the electric heater according to the operating state of the internal combustion engine (that is, by changing the temperature of the exhaust gas introduced into the oxidation catalyst). . As a result, the conventional apparatus adjusts the composition of nitrogen oxides contained in the exhaust gas introduced into the SCR catalyst after passing through the oxidation catalyst to a composition that allows the SCR catalyst to efficiently remove (reducing) nitrogen oxides ( For example, see Patent Document 1.)

JP 2010-265862 A

  As described above, the conventional apparatus adjusts the composition of nitrogen oxides contained in the exhaust gas in consideration of the exhaust gas purification efficiency by the SCR catalyst. On the other hand, as is well known, the purification efficiency of exhaust gas by the SCR catalyst changes not only according to the composition of nitrogen oxides contained in the exhaust gas but also according to “temperature of the SCR catalyst”.

  Regarding the temperature of the SCR catalyst, in the conventional apparatus, the exhaust gas that has passed through the electric heater is introduced into the SCR catalyst after passing through the oxidation catalyst and the DPF. Therefore, even if the heating value of the electric heater is changed to change the temperature of the SCR catalyst, the thermal energy in the exhaust is absorbed by the oxidation catalyst and the DPF before the exhaust reaches the SCR catalyst. For this reason, it is considered that the change in the temperature of the SCR catalyst may not sufficiently follow the change in the heat generation amount of the electric heater. In other words, in the conventional apparatus, although the temperature of the oxidation catalyst or the like provided on the upstream side of the exhaust passage is likely to change, the temperature of the SCR catalyst provided on the downstream side of the exhaust passage is unlikely to change. it is conceivable that.

  As a result, in the conventional apparatus, for example, when the internal combustion engine is cold-started, the oxidation catalyst or the like has an appropriate temperature (hereinafter referred to as “active”) from the viewpoint of sufficiently exerting the function as a catalyst in a relatively short time length. Although it is also referred to as “temperature”), it is believed that the length of time until the temperature of the SCR catalyst reaches the activation temperature may be quite long. On the other hand, if the calorific value of the electric heater is increased so that the temperature of the SCR catalyst reaches the activation temperature in a shorter time length, the temperature of the oxidation catalyst provided upstream of the SCR catalyst becomes excessive. It is considered that there is a possibility that the oxidation catalyst or the like may not be able to fully exhibit their functions (for example, thermally denatured). As can be understood from the above description, the temperature of each of a plurality of members (such as an SCR catalyst and an oxidation catalyst) constituting the conventional apparatus is not limited to the case where the internal combustion engine is cold-started. It may not be properly adjusted.

  However, in order for the exhaust emission control device to efficiently purify the exhaust gas as a whole device, the temperature of each member constituting the device changes as appropriately as possible (for example, changes with good follow-up to an instruction to change the temperature). Or so that it is maintained at the target temperature). Furthermore, as understood from the above description, it is desirable that the temperature of each member constituting the exhaust purification device is appropriately adjusted, not limited to the exhaust purification device having the SCR catalyst.

  In view of the above problems, an object of the present invention is to provide an exhaust gas purification device for an internal combustion engine that can adjust the temperature of each member constituting the exhaust gas purification device as appropriately as possible.

In order to solve the above problems, an exhaust gas purification apparatus for an internal combustion engine according to the present invention comprises:
An exhaust temperature adjusting means that is provided in an exhaust passage of the internal combustion engine and adjusts the temperature of exhaust discharged from the combustion chamber of the internal combustion engine;
A catalyst provided at a position downstream of the exhaust temperature adjusting means in the exhaust passage and purifying the exhaust;
Is provided.

  The “exhaust temperature adjusting means” is not particularly limited as long as it can adjust (change) the exhaust temperature. For example, an electric heater that can give a desired amount of heat energy to the exhaust can be employed as the exhaust temperature adjusting means. It should be noted that “adjusting” the temperature of the exhaust includes increasing the temperature of the exhaust, lowering the temperature of the exhaust, and maintaining the temperature of the exhaust at a specific temperature.

  The “catalyst” is not particularly limited as long as it can purify exhaust gas introduced into the catalyst. Note that “purifying exhaust gas” means removing at least a part of the substances to be purified (for example, nitrogen oxides, unburned substances and particulate substances) contained in the exhaust gas, and is not necessarily purified. It does not mean that all of the target substance is removed from the exhaust.

  With the above configuration, the catalyst is provided at a position “downstream” with respect to the exhaust temperature adjusting means, so that the exhaust gas that has passed through the exhaust temperature adjusting means is introduced into the catalyst. That is, the temperature of the catalyst can be adjusted by adjusting the temperature of the exhaust gas by the exhaust temperature adjusting means.

  The “downstream side” represents a direction corresponding to the moving direction of the exhaust when the exhaust moves in the exhaust passage. For example, the “position downstream of the exhaust temperature adjusting means” represents a position farther from the combustion chamber of the internal combustion engine than the position where the exhaust temperature adjusting means is provided. On the other hand, “upstream side”, which will be described later, represents a direction corresponding to a direction opposite to the moving direction of the exhaust when the exhaust moves in the exhaust passage. For example, “a position upstream from the catalyst” represents a position closer to the combustion chamber than a position where the catalyst is provided.

Furthermore, the exhaust emission control device of the present invention includes:
After at least a portion of the exhaust gas that has passed through the exhaust temperature adjusting means "passed through" at least a portion of the intermediate member provided at a position between the exhaust temperature adjusting means and the catalyst in the exhaust passage, Can be introduced into the catalyst as "first exhaust";
At least a part of the exhaust gas that has passed through the exhaust temperature adjusting means can be introduced into the catalyst as “second exhaust gas” without passing through at least a part of the intermediate member.
Configured as follows.

  With the above configuration, the temperature of the catalyst can be adjusted by the second exhaust (and the first exhaust that has passed through the intermediate member). Here, the second exhaust gas can be introduced into the catalyst “without passing through at least a part” of the intermediate member, so that the second exhaust gas is introduced into the catalyst “through all of the intermediate member”. , The temperature of the catalyst can be adjusted more appropriately (eg, to change in a good manner in response to an instruction to change the temperature, and to be maintained at the target temperature). Further, the temperature of the intermediate member can be appropriately adjusted by the first exhaust. Therefore, the exhaust emission control device of the present invention having the above-described configuration can appropriately adjust the temperature of each member (catalyst and intermediate member) constituting the exhaust emission control device.

  By the way, the “intermediate member” is not particularly limited as long as it is a member provided at a position between the exhaust temperature adjusting means and the catalyst. For example, an oxidation catalyst that can oxidize nitrogen oxides contained in the exhaust, a diesel particulate filter that can collect particulate matter contained in the exhaust, and the like can be employed as the intermediate member. Note that the phrase “can oxidize nitrogen oxides” means that at least a part of the nitrogen oxides contained in the exhaust can be oxidized, and does not necessarily mean that all of the nitrogen oxides can be oxidized. Furthermore, the above-mentioned “capable of collecting particulate matter” means that at least a part of the particulate matter contained in the exhaust gas can be collected, and that all of the particulate matter can be collected. I don't mean.

  Further, the “intermediate member” may be a single member or a plurality of members. When the intermediate member includes a plurality of members, each of the plurality of members may be disposed in the exhaust passage in a state of being connected to each other (in other words, an integrated state), and may be independent of each other. It may be arranged in the exhaust passage in a separated state. The plurality of members are arranged in the exhaust passage in a state in which some of them are connected (integrated) with each other, and in a state in which the other parts are separated from each other. It may be arranged in the exhaust passage.

  The above “at least part of the exhaust gas is configured to be introduced into the catalyst as the first exhaust gas” means that a part or all of the exhaust gas is introduced into the catalyst as the first exhaust gas. It can be formed. In other words, this description represents that such a state can be formed as needed (eg, depending on the operating state of the internal combustion engine), and such a state is not always the case. It does not mean that it needs to be formed.

  Similarly, the above-mentioned “configured such that at least a part of the exhaust gas can be introduced into the catalyst as the second exhaust gas” means that a part or all of the exhaust gas is introduced into the catalyst as the second exhaust gas. Represents that a state can be formed. That is, this description indicates that such a state can be formed as needed (eg, depending on the operating state of the internal combustion engine), and such a state need not always be formed. Does not mean there is.

  Therefore, in the exhaust emission control device according to the present invention, depending on the situation (for example, since the temperature of the catalyst has reached the activation temperature after the internal combustion engine is cold started, it is not necessary to heat the catalyst directly by the second exhaust gas). The amount of the second exhaust may be zero. Conversely, in some situations (for example, when the internal combustion engine is cold-started, it is considered that the catalyst needs to be heated particularly quickly), the amount of the second exhaust is the total amount of exhaust. There may be cases.

  Further, as can be understood from the above description, in the exhaust emission control device of the present invention, the exhaust gas other than the first exhaust gas and the second exhaust gas (for example, the catalyst through the path different from the first exhaust gas and the second exhaust gas). There is no denying that there is exhaust to be introduced.

  Next, some aspects (aspects A to J) of the exhaust emission control device of the present invention will be described.

・ Aspect A
As described above, in the exhaust purification apparatus of the present invention, the temperature of the intermediate member can be adjusted by the first exhaust, and the temperature of the catalyst can be adjusted by the second exhaust. Here, it is considered that the “amount” of the second exhaust gas is desirably adjusted in accordance with parameters related to exhaust gas purification in the catalyst.

Therefore, for example, as an example of a specific configuration, the exhaust purification device of the present invention is
The amount of the second exhaust gas may be adjusted based on the temperature of at least one of the catalyst and the intermediate member.

  Thus, the amount of the second exhaust can be adjusted to an amount suitable for the temperature of at least one of the catalyst and the intermediate member.

  The method for obtaining the temperature of at least one of the catalyst and the intermediate member is not particularly limited. These temperatures may be measured by a temperature sensor, for example, or may be estimated based on specific operating parameters of the internal combustion engine.

・ Aspect B
In the exhaust gas purification apparatus of the present invention, at least a part of the exhaust gas that has passed through the exhaust gas temperature adjusting means can be introduced into the catalyst as a first exhaust gas, and at least a part of the exhaust gas can be introduced into the catalyst as a second exhaust gas Such a configuration is not particularly limited.

For example, as an example of a specific configuration, the exhaust purification device of the present invention is
A “bypass passage” through which the second exhaust passes, wherein one end of the bypass passage is “(A) a position where the exhaust temperature adjusting means is provided or a position downstream of the exhaust temperature adjusting means”. And (B) the position upstream of the intermediate member or the position where the intermediate member is provided ”and the other end of the bypass passage is connected to“ (C) the intermediate member ”. Connected to the exhaust passage at a position where a member is provided or a position downstream of the intermediate member and (D) a position upstream of the catalyst or a position where the catalyst is provided The second exhaust gas may be introduced into the catalyst through a bypass passage.

  With the above configuration, one end of the bypass passage is provided at “(A) a position where the exhaust temperature adjusting means is provided or a position downstream of the exhaust temperature adjusting means”. At least a part of the exhaust (second exhaust) ”can flow into the bypass passage.

Further, “(B) a position upstream of the intermediate member or a position where the intermediate member is provided” is provided with one end of the bypass passage, and “(C) a position where the intermediate member is provided. Alternatively, since the other end of the bypass passage is provided at “a position downstream of the intermediate member”, the second exhaust gas can move “without passing through at least a part of the intermediate member”.

  In addition, since the other end of the bypass passage is provided at “(D) a position upstream of the catalyst or a position where the catalyst is provided”, the second exhaust gas can be “introduced into the catalyst”.

  Therefore, with the above-described configurations (A to D), the exhaust emission control device according to the present invention is configured such that “at least a part of the exhaust gas that has passed through the exhaust gas temperature adjusting means passes through at least a part of the intermediate member, It is possible to be introduced to "."

  By the way, the above-mentioned “position where the exhaust temperature adjusting means is provided” means “at least part of the exhaust gas that passes through the position and flows into the bypass passage is provided with the exhaust temperature adjusting means in the exhaust passage. Represents the position where it will flow into the bypass passage without going through any part. The “position at which the intermediate member is provided” means that at least a part of the exhaust gas that passes through the position and flows into the bypass passage or flows out of the bypass passage is provided with the intermediate member in the exhaust passage. The position which flows out from a bypass channel | path, or flows into a bypass channel | path, without passing through the part which is not shown. Similarly, the “position where the catalyst is provided” means that at least a part of the exhaust gas passing through the position and flowing out of the bypass passage does not pass through a portion of the exhaust passage where the catalyst is not provided. It represents the position that will flow out of the bypass passage.

  When the intermediate member is configured by a plurality of members, the “position where the intermediate member is provided” represents a position where at least one of the plurality of members is provided. In this case, the “position downstream of the intermediate member” represents a position downstream of at least one of the plurality of members. Therefore, when a plurality of members are arranged in the exhaust passage in a state of being separated from each other, the “position downstream of the intermediate member” is a position between one member and another member. possible.

・ Aspect C
In the exhaust purification apparatus of the present invention, the specific configuration for adjusting the amount of the second exhaust is not particularly limited.

For example, as an example of a specific configuration, an exhaust purification device having the bypass passage is
A control valve that is a “control valve” for adjusting the amount of the second exhaust that passes through the bypass passage, and in which the amount of the second exhaust changes according to the opening of the control valve, is provided in the bypass passage. Provided,
The opening degree of the control valve may be changed based on the temperature of at least one of the catalyst and the intermediate member.

  The “control valve” is not particularly limited as long as it is a valve that changes the amount of the second exhaust gas according to the opening. As the control valve, for example, a valve (for example, a swing arm type valve and a butterfly valve) having a plate-like member that can rotate around a specific axis may be employed.

・ Mode D
As described above, in the exhaust gas purification apparatus of the present invention, the catalyst for purifying the exhaust gas is not particularly limited.

For example, as an example of a specific catalyst,
A catalyst that purifies the exhaust gas by reducing nitrogen oxides contained in the exhaust gas may be employed.

  The specific configuration of the catalyst is not particularly limited. For example, as the catalyst, an SCR catalyst having a configuration in which a catalyst component (zeolite-based catalyst, vanadium-based catalyst, etc.) is supported on a carrier (ceramics, etc.), a catalyst component (noble metal, etc.), an oxygen storage material, and a NOx storage material. A NOx occlusion reduction catalyst supported on a carrier and a DPNR (Diesel Particulate-NOx Reduction) catalyst capable of removing both nitrogen oxides and particulate matter from the exhaust gas can be employed.

・ Mode E
Furthermore, the exhaust gas purification apparatus having the above catalyst is an example of a specific configuration.
It may be configured to include a reducing agent supply means for supplying a reducing agent into the exhaust gas introduced into the catalyst.

  The “reducing agent supply means” is not particularly limited as long as it is a means capable of supplying the reducing agent into the exhaust gas until the exhaust gas discharged from the combustion chamber is introduced into the catalyst. For example, an injector that injects the reducing agent into the exhaust can be employed as the reducing agent supply means. The position where the reducing agent supply means is provided is not particularly limited as long as it can supply the reducing agent to the exhaust gas introduced into the catalyst. For example, the reducing agent supply means can be provided at a position upstream of the catalyst in the exhaust passage.

  The “reducing agent” is not particularly limited as long as it contains a substance capable of reducing nitrogen oxides contained in exhaust gas (or a substance capable of reducing nitrogen oxides can be generated from the reducing agent). As the reducing agent, for example, an aqueous urea solution and ammonia can be employed.

・ Aspect F
In the exhaust emission control device having the reducing agent supply means, the exhaust gas is purified by the reaction of the reducing agent supplied into the exhaust gas from the reducing agent supply means and the nitrogen oxide in the exhaust gas in the catalyst. become. Therefore, in order to efficiently purify the exhaust gas, the reducing agent is appropriately supplied into the exhaust gas from the reducing agent supply means (for example, the amount of the supplied reducing agent and the dispersion of the supplied reducing agent into the exhaust gas). It is considered preferable to be supplied (in terms of degree, etc.). On the other hand, for example, the flow of the reducing agent is significantly reduced (for example, the reducing agent is frozen or a specific component is deposited in the reducing agent). It is not desirable that the reducing agent is not properly supplied into the exhaust from the means.

Therefore, as an example of a specific configuration, the exhaust purification device of the present invention is
Before the second exhaust gas is introduced into the catalyst, the second exhaust gas may pass through a position where the reducing agent supply means is provided.

  As a result, not only the temperature of the catalyst but also the temperature of the reducing agent supply means can be changed by the second exhaust. Therefore, for the same reason as the adjustment of the catalyst temperature, the temperature of the reducing agent supplying means can be adjusted appropriately.

  Therefore, for example, even when the flowability of the reducing agent is significantly reduced when the internal combustion engine is cold started, the reducing agent fluidity is heated by the first exhaust gas. It can be raised earlier than in the case. As a result, even in this case, the reducing agent can be appropriately supplied earlier into the exhaust gas.

・ Mode G
Further, in the exhaust emission control device having the reducing agent supply means, it is considered desirable to adjust the amount of the second exhaust gas according to the parameters related to the exhaust gas purification in the catalyst, as described above.

Therefore, as an example of a specific configuration, an exhaust purification device having the above reducing agent supply means,
The second exhaust amount may be adjusted based on the temperature of at least one of the catalyst, the intermediate member, and the reducing agent supply means.

・ Mode H
Incidentally, as described above, the exhaust gas from the internal combustion engine generally contains not only nitrogen oxides but also particulate matter (PM). Here, it is considered desirable that the amount of particulate matter (PM) contained in the exhaust gas introduced into the catalyst is as small as possible.

Therefore, as an example of a specific configuration, the exhaust purification device of the present invention is
Before the second exhaust is introduced into the catalyst, the second exhaust may pass through a filter for removing particulate matter contained in the exhaust.

  With the above configuration, the amount of particulate matter contained in the exhaust gas introduced into the catalyst is reduced by the filter. Therefore, it is possible to prevent the performance of the catalyst from being deteriorated by the particulate matter and that the particulate matter passes through the catalyst and is released to the outside of the internal combustion engine.

  By the way, the above “removing the particulate matter” means removing (for example, collecting) at least a part of the particulate matter contained in the exhaust gas from the exhaust gas. Does not mean to be removed from the exhaust.

  As can be understood from the above description, when a catalyst (for example, the DPNR) having a property of removing particulate matter by itself is applied to the exhaust purification device, the exhaust purification device does not necessarily have the second exhaust. It may not be configured to pass through the filter prior to being introduced into the catalyst.

・ Mode I
In the exhaust gas purification apparatus having the filter, the specific configuration in which the second exhaust gas passes through the filter is not particularly limited.

For example, as an example of a specific configuration, the exhaust purification device of the present invention is
The intermediate member includes a filter for removing particulate matter contained in the exhaust;
The second exhaust may be configured to pass through at least a portion of the filter.

  More specifically, for example, when the exhaust purification device of the present invention has the bypass passage, the exhaust purification device of the present aspect includes the filter in which the “previous” exhaust gas flowing into the bypass passage is included in the intermediate member. It may be configured to pass (for example, such that the one end of the bypass passage is provided at “position (B) where the intermediate member is provided)”, and the “rear” exhaust gas flowing out of the bypass passage is It may be configured so as to pass through the filter (for example, so that the other end of the bypass passage is provided at the “position (C) where the intermediate member is provided)”.

・ Aspect J
On the other hand, as another example of a specific configuration in which the second exhaust gas passes through the filter, the exhaust gas purification apparatus of the present invention includes:
A filter for removing particulate matter contained in the exhaust gas may be provided in the bypass passage, and the second exhaust gas may be introduced into the catalyst through the bypass passage.

  The filter provided in the bypass passage may be the same filter as the filter included in the intermediate member described above or a different filter in terms of exhaust purification performance and the like. For example, the ability of the filter provided in the bypass passage to remove particulate matter in the exhaust may be lower than the ability of the filter included in the above-described intermediate member to remove particulate matter in the exhaust (so-called low It may be a capacity filter.)

  As described above, the present invention has an effect that the temperature of each member (for example, a catalyst, an intermediate member, and a reducing agent supply means) constituting the exhaust gas purification apparatus can be adjusted appropriately as much as possible.

It is the schematic which shows the concept of the exhaust gas purification apparatus which concerns on 1st Embodiment of this invention. It is the schematic of the internal combustion engine to which the exhaust gas purification apparatus which concerns on 2nd Embodiment of this invention is applied. FIG. 3 is a schematic view showing another aspect of the internal combustion engine shown in FIG. 2. FIG. 3 is a schematic view showing another aspect of the internal combustion engine shown in FIG. 2. FIG. 3 is a schematic view showing another aspect of the internal combustion engine shown in FIG. 2. It is the schematic which shows the concept of the exhaust gas purification apparatus which concerns on 3rd Embodiment of this invention. It is a schematic diagram of a part of an internal combustion engine to which an exhaust emission control device according to a fourth embodiment of the present invention is applied. It is the schematic which shows the concept of the exhaust gas purification apparatus which concerns on 5th Embodiment of this invention. It is a schematic diagram of a part of an internal combustion engine to which an exhaust gas purification apparatus according to a sixth embodiment of the present invention is applied. FIG. 10 is a schematic view showing another aspect of the internal combustion engine shown in FIG. 9. It is the schematic which shows the concept of the exhaust gas purification apparatus which concerns on 7th Embodiment of this invention. It is a schematic diagram of a part of an internal combustion engine to which an exhaust gas purification apparatus according to an eighth embodiment of the present invention is applied. It is the schematic which shows the concept of the exhaust gas purification apparatus which concerns on 9th Embodiment of this invention. It is a schematic diagram of a part of an internal combustion engine to which an exhaust gas purification apparatus according to a tenth embodiment of the present invention is applied. It is a schematic diagram of a part of an internal combustion engine to which an exhaust emission control system according to an eleventh embodiment of the present invention is applied.

  Hereinafter, each embodiment (1st Embodiment-11th Embodiment) of the exhaust gas purification device by this invention is described, referring drawings.

(First embodiment)
Hereinafter, an exhaust emission control device (hereinafter also referred to as “first device”) according to a first embodiment of the present invention will be described with reference to FIGS. 1 (a) and 1 (b). Fig.1 (a) and FIG.1 (b) are schematic which shows the concept of a 1st apparatus.

  As shown in FIGS. 1A and 1B, the exhaust discharged from the combustion chamber of the internal combustion engine to the exhaust passage (not shown) is supplied to the exhaust temperature adjusting means before being introduced into the catalyst. (Specific examples of the catalyst and the exhaust gas temperature adjusting means will be described later). That is, the catalyst is provided at a position downstream of the exhaust temperature adjusting means in the exhaust passage. The temperature of the exhaust is adjusted by the exhaust temperature adjusting means.

  Part of the exhaust gas that has passed through the exhaust gas temperature adjusting means is introduced into the intermediate member before being introduced into the catalyst (a specific example of the intermediate member will be described later). In other words, in the first device, the intermediate member is provided at a position between the exhaust temperature adjusting means and the catalyst. The exhaust gas that has passed through the intermediate member is introduced into the catalyst as first exhaust gas.

  In FIG. 1A, the first exhaust is displayed so as to be introduced into the catalyst after passing through the entire intermediate member. However, the first exhaust gas may be introduced into the catalyst after passing through a part of the intermediate member. The first device can include both of these aspects. That is, the first device is configured to be introduced into the catalyst after a part of the exhaust gas passes through at least a part of the intermediate member.

  On the other hand, the other part of the exhaust gas that has passed through the exhaust temperature adjusting means does not pass through the entire intermediate member as shown in FIG. 1 (a), or is intermediate as shown in FIG. 1 (b). After passing through a part of the member, it is introduced into the catalyst as the second exhaust. The first device can include both of these aspects. That is, the first device is configured such that the other part of the exhaust gas is introduced into the catalyst without passing through at least a part of the intermediate member.

  By the way, in FIGS. 1A and 1B, the exhaust gas that has passed through the exhaust gas temperature adjusting means is displayed to belong to either the first exhaust gas or the second exhaust gas. However, this display is merely a convenience for easy understanding. That is, the first device may be configured such that another exhaust gas different from the first exhaust gas and the second exhaust gas (for example, exhaust gas passing through another member different from the intermediate member) is introduced into the catalyst. .

Further, as described above, the first device need not be configured such that both the first exhaust and the second exhaust always exist. That is, the first device has a state in which at least a part of the exhaust gas is introduced into the catalyst as the first exhaust gas and at least a part of the exhaust gas is introduced into the catalyst as the second exhaust gas (for example, according to the operating state of the internal combustion engine It is configured to be formed.
The above is the description of the first device.

(Second Embodiment)
Next, as an example in which the concept shown in the first device is actually applied to an internal combustion engine, an embodiment in which “a bypass passage through which the second exhaust gas can pass is provided in the exhaust passage” will be described. Hereinafter, the exhaust emission control device in this embodiment is also referred to as a “second device”.

<Outline of device>
FIG. 2 shows a schematic configuration of a system in which the second device is applied to the internal combustion engine 10. The internal combustion engine 10 is a four-cylinder diesel engine having four cylinders, a first cylinder to a fourth cylinder. Hereinafter, for convenience, the “internal combustion engine 10” is also simply referred to as “engine 10”.

  As shown in FIG. 2, the engine 10 includes an engine body 20 including a fuel injection system, an intake system 30 for introducing air into the engine body 20, and gas discharged from the engine body 20 to the outside of the engine 10. An exhaust system 40 for discharging, a supercharger 50 for compressing air that is driven by the energy of the exhaust and introduced into the engine body 20, and an EGR device 60 for recirculating the exhaust gas from the exhaust system 40 to the intake system 30 Various sensors 71 to 76 and an electronic control unit 80 are provided.

  The engine body 20 includes a cylinder head 21 to which an intake system 30 and an exhaust system 40 are connected, and a plurality of fuel injection devices 22 provided on the cylinder head 21. The fuel injection device 22 is configured to inject fuel into the combustion chamber in response to an instruction signal from the electronic control device 80.

  The intake system 30 includes an intake port (not shown) formed in the cylinder head 21, an intake manifold 31 communicated with each cylinder via the intake port, and an intake pipe connected to a collective portion on the upstream side of the intake manifold 31. 32, a throttle valve (intake throttle valve) 33 that can change the opening area (opening cross-sectional area) in the intake pipe 32, a throttle valve actuator 33 a that rotationally drives the throttle valve 33, and an intake pipe upstream of the throttle valve 33 And an air cleaner 35 provided at the end of the intake pipe 32 upstream of the supercharger 50 provided upstream of the intercooler 34. The intake manifold 31 and the intake pipe 32 constitute an intake passage.

  The exhaust system 40 includes an exhaust port (not shown) formed in the cylinder head 21, an exhaust manifold 41 communicated with each cylinder via the exhaust port, and an exhaust pipe connected to a downstream gathering portion of the exhaust manifold 41. 42, an electric heater 43 provided downstream of the supercharger 50 provided in the exhaust pipe 42, a diesel particulate filter (DPF) 44 provided downstream of the electric heater 43, and an exhaust purification catalyst (For example, NOx occlusion reduction catalyst. Hereinafter, simply referred to as “catalyst”) 45. The exhaust manifold 41 and the exhaust pipe 42 constitute an exhaust passage.

  The electric heater 43 changes the heat generation amount (in other words, the temperature of the exhaust gas passing through the electric heater 43) in accordance with an instruction signal from the electronic control device 80. Furthermore, a bypass passage 46 is provided in the exhaust system 40. One end of the bypass passage 46 is located downstream of the electric heater 43 and connected to the exhaust pipe 42 at a position upstream of the DPF 44, and the other end is located downstream of the DPF 44. In addition, the exhaust pipe 42 is connected at a position upstream of the catalyst 45.

  The supercharger 50 includes a compressor 51 provided in the intake passage (intake pipe 32) and a turbine 52 provided in the exhaust passage (exhaust pipe 42). The supercharger 50 is configured to compress the air introduced into the compressor 51 (that is, the air introduced into the combustion chamber) using the energy of the exhaust gas introduced into the turbine 52.

  The EGR device 60 includes an exhaust gas recirculation pipe 61 that constitutes a passage (EGR passage) that recirculates exhaust gas from the exhaust manifold 41 to the intake manifold 31, an EGR gas cooling device (EGR cooler) 62 provided in the exhaust gas recirculation pipe 61, and And an EGR control valve 63 provided in the exhaust gas recirculation pipe 61. The EGR control valve 63 changes the amount of exhaust gas recirculated in accordance with an instruction signal from the electronic control device 80.

  As various sensors 71 to 76, an air introduction amount sensor 71, an intake air temperature sensor 72, a supercharging pressure sensor 73, a crank position sensor 74, an exhaust gas temperature sensor 75, and an accelerator opening sensor 76 are provided.

  The air introduction amount sensor 71 is provided in the intake passage (intake pipe 32). The air introduction amount sensor 71 outputs a signal corresponding to the mass flow rate of air flowing through the intake pipe 32 (that is, the mass of air sucked into the engine 10).

  The intake air temperature sensor 72 is provided in the intake passage (intake pipe 32). The intake air temperature sensor 72 outputs a signal corresponding to the intake air temperature, which is the temperature of the air flowing through the intake pipe 32.

  The supercharging pressure sensor 73 is provided in the intake pipe 32 on the downstream side of the throttle valve 33. The supercharging pressure sensor 73 outputs a signal representing the pressure of air in the intake pipe 32 (that is, the supercharging pressure provided by the supercharger 50).

  The crank position sensor 74 is provided in the vicinity of a crankshaft (not shown). The crank position sensor 74 outputs a signal corresponding to the rotation of the crankshaft (that is, a signal corresponding to the engine rotation speed).

  The exhaust temperature sensor 75 is provided at a position downstream of the electric heater 43 and in the vicinity of a position where one end of the bypass passage 46 is connected to the exhaust pipe 42. The exhaust temperature sensor 75 outputs a signal corresponding to the temperature of the exhaust flowing through the exhaust pipe 42.

  The accelerator opening sensor 76 is provided on an accelerator pedal AP that is operated by an operator of the engine 10. The accelerator opening sensor 76 outputs a signal corresponding to the opening of the accelerator pedal AP.

  The electronic control unit 80 includes a CPU 81, a ROM 82 in which programs executed by the CPU 81, tables (maps), constants, and the like are stored in advance, a RAM 83 in which the CPU 81 temporarily stores data as necessary, and data in a state where power is turned on. And a backup RAM 84 that holds the stored data while the power is shut off, and an interface 85 including an AD converter. The CPU 81, ROM 82, RAM 83, RAM 84, and interface 85 are connected to each other via a bus.

  The interface 85 is connected to the various sensors described above, and transmits a signal output from them to the CPU 81. Further, the interface 85 is connected to the fuel injection device 22, the actuator 33a, the electric heater 43, the EGR control valve 63, and the like, and sends an instruction signal to them in response to an instruction from the CPU 81.

<Outline of device operation>
Hereinafter, an outline of the operation of the second device applied to the engine 10 will be described.
Air taken into the intake passage from the outside of the engine 10 is introduced into each combustion chamber (cylinder) via the air cleaner 35, the compressor 51, the intercooler 34, the throttle valve 33, and the intake manifold 31 in this order. The At this time, the amount of air introduced into the combustion chamber is adjusted by the throttle valve 33, and the pressure of the air is changed by the compressor 51. At this time, the air introduction amount sensor 71, the intake air temperature sensor 72, and the supercharging pressure sensor 73 confirm the amount, temperature, and pressure of air introduced into the combustion chamber.

  When air introduced into the combustion chamber is compressed by a piston (not shown), fuel is injected from the injector 22 into the compressed air at a predetermined timing. As a result, the fuel self-ignites and burns. When the engine 10 is operating due to the combustion of fuel, the engine rotational speed is confirmed by the crank position sensor 74.

  Then, the burned gas (exhaust gas) is discharged from the combustion chamber to the exhaust passage. Exhaust gas is introduced into the electric heater 43 through the exhaust manifold 41 and the turbine 52 in this order. The amount of heat generated by the electric heater 43 is adjusted based on an instruction signal from the electronic control unit 80 determined based on the operating state of the engine 10 and the temperature of the exhaust gas confirmed by the exhaust temperature sensor 75. Thereby, the temperature of the exhaust gas passing through the electric heater 43 is adjusted.

  Part of the exhaust gas that has passed through the electric heater 43 passes through the bypass passage 46 (without passing through the DPF 44) and is introduced into the catalyst 45. On the other hand, the other part of the exhaust gas that has passed through the electric heater 43 is introduced into the DPF 44 without flowing into the bypass passage 46. The exhaust gas that has passed through the DPF 44 is introduced into the catalyst 45. Then, the exhaust gas that has passed through the catalyst 45 is released to the outside of the engine 10.

  A part of the exhaust discharged from the combustion chamber flows into the exhaust gas recirculation pipe 61 from the exhaust manifold 41, passes through the EGR cooler 62 and the EGR control valve 63, and then recirculates to the intake manifold 31. The amount of exhaust gas (EGR gas) to be recirculated is adjusted by the EGR control valve 63.

  With the above configuration, for example, when the engine 10 is cold-started, a part of the exhaust gas that has passed through the electric heater 43 is introduced into the catalyst 45 without passing through the DPF 44. As a result, the temperature of the catalyst 45 can be raised (that is, warmed up) to its activation temperature more quickly.

  By the way, in the configuration of the second device shown in FIG. 2, one end of the bypass passage 46 is connected to the exhaust passage at a position downstream of the electric heater 43 and upstream of the DPF 44. The other end is connected to the exhaust passage at a position downstream of the DPF 44 and upstream of the catalyst 45. However, the position where one end and the other end of the bypass passage 46 are connected is not limited to the position shown in FIG.

  Hereinafter, another aspect of the engine 10 shown in FIG. 2 will be described with reference to FIGS. 3 to 5 are schematic views of part of the exhaust passage (from the turbine 52 to the catalyst 45) in FIG.

  For example, in the second device, as shown in FIG. 3A, one end of the bypass passage 46 is connected to the exhaust passage at a position downstream of the electric heater 43 and upstream of the DPF 44. In addition, the other end may be configured to be connected to the exhaust passage at a position where the DPF 44 is provided. In the second device, as shown in FIG. 3B, one end of the bypass passage 46 is connected to the exhaust passage at a position downstream of the electric heater 43 and upstream of the DPF 44. In addition, the other end may be configured to be connected to the exhaust passage at a position where the DPF 44 is provided.

  Further, as shown in FIG. 4C, the second device has one end of the bypass passage 46 connected to the exhaust passage at a position where the electric heater 43 is provided, and the other end downstream of the DPF 44. It may be configured to be connected to the exhaust passage at a position on the side and upstream of the catalyst 45. Further, as shown in FIG. 4D, the second device has one end of the bypass passage 46 connected to the exhaust passage at the position where the electric heater 43 is provided, and the other end provided with the DPF 44. It may be configured such that it is connected to the exhaust passage at a position. Further, as shown in FIG. 4 (e), the second device has one end of the bypass passage 46 connected to the exhaust passage at a position where the electric heater 43 is provided, and the other end provided with the catalyst 45. It may be configured such that it is connected to the exhaust passage at the position where it is located.

In addition, as shown in FIG. 5 (f), the second device has one end of the bypass passage 46 connected to the exhaust passage at a position where the DPF 44 is provided, and the other end downstream of the DPF 44. And may be configured to be connected to the exhaust passage at a position upstream of the catalyst 45. In the second device, as shown in FIG. 5G, one end of the bypass passage 46 is connected to the exhaust passage at a position where the DPF 44 is provided, and the other end is provided with the DPF 44. It may be configured to be connected to a position. Further, as shown in FIG. 5 (h), the second device is connected to the exhaust passage at one end of the bypass passage 46 at the position where the DPF 44 is provided, and at the position where the catalyst 45 is provided. It may be configured to be connected to the exhaust passage.
The above is the description of the second device.

(Third embodiment)
Next, an embodiment in which the amount of the second exhaust gas is adjusted in addition to the concept shown in the first device will be described with reference to FIG. FIG. 6 is a schematic view showing the concept of an exhaust emission control device (hereinafter also referred to as “third device”) according to this embodiment.

  As shown in FIG. 6, the third device differs from the first device only in that the amount of the second exhaust is adjusted based on the temperature of at least one of the catalyst and the intermediate member.

As in FIGS. 1A and 1B referred to in the first device, in FIG. 6, the exhaust gas that has passed through the exhaust temperature adjusting means belongs to either the first exhaust gas or the second exhaust gas. Is displayed. However, as with the first device, this display is merely a convenience for ease of understanding. Further, like the first device, the third device need not be configured such that both the first exhaust and the second exhaust always exist.
The above is the description of the third device.

(Fourth embodiment)
Next, an embodiment in which “a control valve is provided in the bypass passage” will be described as an example in which the concept shown in the third device is actually applied to the internal combustion engine. Hereinafter, the exhaust emission control device in this embodiment is also referred to as a “fourth device”.

  The internal combustion engine to which the fourth device is applied has the same configuration as the engine 10 shown in the second device, except that a control valve is provided in the bypass passage 46 in FIG. Therefore, a specific description of each member constituting the internal combustion engine to which the fourth device is applied (hereinafter also referred to as “engine 10” for convenience) is omitted as necessary.

  FIG. 7 is a schematic view of a part of the exhaust passage (from the turbine 52 to the catalyst 45) in the fourth device. As shown in FIG. 7, a bypass passage 46 similar to the second device is provided in the exhaust system of the engine 10. However, a control valve 47 is provided in the bypass passage 46. The control valve 47 is a control valve for adjusting the amount of the second exhaust that passes through the bypass passage 46, and the amount of the second exhaust changes according to the opening of the control valve 47. is there. The control valve 47 is electrically connected to the electronic control device 80, and the opening degree of the control valve 47 is an instruction from the electronic control device 80 determined based on the temperature of at least one of the intermediate member 44 and the catalyst 45. It is adjusted based on the signal. As a result, the amount of exhaust (second exhaust) passing through the bypass passage 46 is adjusted.

  For example, the opening degree of the control valve 47 is fully opened when the temperature of the catalyst 45 is lower than a predetermined threshold temperature, and fully closed when the temperature of the catalyst 45 is equal to or higher than the threshold temperature. Can be adjusted as follows. Further, for example, the opening degree of the control valve 47 can be adjusted such that the opening degree is larger as the temperature of the catalyst 45 is lower.

  The temperatures of the intermediate member 44 and the catalyst 45 may be, for example, measured values measured by a temperature sensor provided on them, and are estimated values estimated from the exhaust gas temperature acquired by the exhaust gas temperature sensor 75 or the like. There may be.

  With the above configuration, an amount of the second exhaust corresponding to the temperature of the catalyst 45 and the intermediate member 44 is introduced into the catalyst 45. As a result, the temperatures of the catalyst 45 and the intermediate member 44 can be adjusted in a short time by an appropriate temperature in terms of exhibiting the functions of these members.

In addition, the position where the one end and the other end of the bypass passage 46 are connected in the fourth device is not limited to the position shown in FIG. 7 as in the second device (see, for example, FIGS. 3 to 5).
The above is the description of the fourth device.

(Fifth embodiment)
Next, in addition to the concept shown in the first apparatus, an embodiment in which “reducing agent is supplied into the exhaust gas introduced into the catalyst” will be described with reference to FIG. FIG. 8 is a schematic view showing the concept of an exhaust emission control device (hereinafter also referred to as “fifth device”) according to this embodiment.

  As shown in FIG. 8A and FIG. 8B, the fifth device has a reducing agent supplied from the reducing agent supply means to the exhaust gas (one or both of the first exhaust gas and the second exhaust gas) introduced into the catalyst. It differs from the first device only in that it is supplied.

  With the above configuration, when an SCR catalyst or the like that selectively removes (reduces) nitrogen oxides contained in the exhaust gas is used as the catalyst, the exhaust gas can be appropriately purified.

8A and 8B, the exhaust gas that has passed through the exhaust gas temperature adjusting means is displayed so as to belong to either the first exhaust gas or the second exhaust gas. However, as with the first device, this display is merely a convenience for ease of understanding. Further, like the first device, the fifth device does not have to be configured such that both the first exhaust and the second exhaust always exist.
The above is the description of the fifth device.

(Sixth embodiment)
Next, as an example in which the concept shown in the fifth device is actually applied to an internal combustion engine, an embodiment in which “reducing agent supply means is provided at a position upstream of the catalyst” will be described. Hereinafter, the exhaust emission control device in this embodiment is also referred to as “sixth device”.

  The internal combustion engine to which the sixth device is applied is that the catalyst 45 in FIG. 2 is an SCR catalyst that removes nitrogen oxides in the exhaust gas using a reducing agent, and is reduced upstream of the catalyst 45 in FIG. Except for the point provided with the agent supply means (reference numeral 48 described later), it has the same configuration as the engine 10 shown in the second device. Therefore, a specific description of each member constituting the internal combustion engine to which the sixth device is applied (hereinafter also referred to as “engine 10” for convenience) is omitted as necessary.

  FIG. 9 is a schematic diagram illustrating a part of the exhaust passage (from the turbine 52 to the catalyst 45) in the sixth device. As shown in FIG. 9, in the exhaust system of the engine 10, the reducing agent supply means 48 (for example, reducing agent is injected) between the position where the other end of the bypass passage 46 is connected to the exhaust passage and the catalyst 45. Injector). The reducing agent supply means 48 supplies a reducing agent (for example, urea water) into the exhaust gas introduced into the catalyst 45 based on an instruction signal from the electronic control unit 80.

  The catalyst 45 is an SCR catalyst having a configuration in which catalyst components (zeolite-based catalyst, vanadium-based catalyst, etc.) are supported on a carrier (ceramics, etc.). The catalyst 45 purifies the exhaust gas by reducing the nitrogen oxides into water and carbon dioxide by reacting the nitrogen oxides in the exhaust gas with the reducing agent supplied from the reducing agent supply means 48.

  As shown in FIG. 9, in the sixth device, the second exhaust passes through the position where the reducing agent supply means 48 is provided before the second exhaust is introduced into the catalyst 45. . Thereby, for example, when the engine 10 is cold-started, not only the catalyst 45 but also the reducing agent supply means 48 is heated by a part of the exhaust gas (second exhaust gas) that has passed through the electric heater 43. As a result, the reducing agent and the reducing agent supply means 48 are rapidly heated even when the flowability of the reducing agent is reduced due to the reason that the reducing agent is frozen at the cold start. The reducing agent can be appropriately supplied earlier.

  By the way, in the configuration of the sixth device shown in FIG. 9, the reducing agent supply means 48 is provided at a position downstream of the other end of the bypass passage 46 and upstream of the catalyst 45. . However, the position where the reducing agent supply means 48 is provided is not limited to the position shown in FIG.

For example, the sixth device may be configured such that the reducing agent supply means 48 is provided in the bypass passage 46 as shown in FIG. Further, for example, when the reducing agent supply means 48 does not need to be made so quickly, the sixth device is configured such that the reducing agent supply means 48 is located downstream of the intermediate member 44 as shown in FIG. And the other end of the bypass passage 46 may be provided at a position upstream of the position connected to the exhaust passage.
The above is the description of the sixth device.

(Seventh embodiment)
Next, in addition to the concept shown in the fifth device, an embodiment in which the amount of second exhaust gas is adjusted will be described with reference to FIG. FIG. 11 is a schematic view showing the concept of an exhaust emission control device (hereinafter also referred to as “seventh device”) according to this embodiment.

  As shown in FIG. 11, the seventh device differs from the fifth device only in that the amount of the second exhaust is adjusted based on the temperature of at least one of the catalyst, the intermediate member, and the reducing agent supply means. To do.

As in the drawing referred to in the fifth device (FIG. 8), in FIG. 11, the exhaust gas that has passed through the exhaust gas temperature adjusting means is displayed as belonging to either the first exhaust gas or the second exhaust gas. . However, like the fifth device, this display is merely a convenience for ease of understanding. Further, like the fifth device, the seventh device does not have to be configured such that both the first exhaust and the second exhaust always exist.
The above is the description of the seventh device.

(Eighth embodiment)
Next, as an example in which the concept shown in the seventh apparatus is actually applied to an internal combustion engine, an embodiment “a control valve is provided in a bypass passage” will be described. Hereinafter, the exhaust emission control device in this embodiment is also referred to as “eighth device”.

  The internal combustion engine to which the eighth device is applied has the same configuration as the engine 10 shown in the sixth device, except that a control valve is provided in the bypass passage 46 in FIG. Therefore, a specific description of each member constituting the internal combustion engine to which the eighth device is applied (hereinafter also referred to as “engine 10” for convenience) is omitted as necessary.

  FIG. 12 is a schematic diagram illustrating a part of the exhaust passage (from the turbine 52 to the catalyst 45) in the sixth device. As shown in FIG. 12, a control valve 47 is provided in the bypass passage 46. The control valve 47 is electrically connected to the electronic control unit 80, and the opening degree of the control valve 47 is adjusted based on the temperature of at least one of the intermediate member 44, the catalyst 45, and the reducing agent supply unit 48. . As a result, the amount of exhaust (second exhaust) passing through the bypass passage 46 is adjusted.

  Similar to the fourth device, the temperatures of the intermediate member 44, the catalyst 45, and the reducing agent supply means 48 may be measured values measured by a temperature sensor provided in them, and are acquired by the exhaust temperature sensor 75, for example. It may be an estimated value estimated from the temperature of exhaust gas.

  With the above configuration, the second exhaust gas in an amount corresponding to the temperatures of the catalyst 45, the intermediate member 44, and the reducing agent supply means 48 is introduced into the catalyst 45. As a result, the temperatures of the catalyst 45, the intermediate member 44, and the reducing agent supply means 48 can be adjusted in a short time by an appropriate temperature in terms of exhibiting the functions of these members.

In addition, the position where one end and the other end of the bypass passage 46 are connected in the eighth device and the position where the reducing agent supply means 48 is provided are not limited to the positions shown in FIG. 12 (for example, FIG. 3 to FIG. 3). 5, see FIG.
The above is the description of the eighth device.

(Ninth embodiment)
Next, in addition to the concept shown in the fifth device, an embodiment in which “the second exhaust passes through a filter for removing particulate matter contained in the exhaust” will be described with reference to FIG. FIG. 13 is a schematic view showing the concept of an exhaust emission control device (hereinafter also referred to as “ninth device”) according to this embodiment.

  As shown in FIG. 13, the ninth device is such that the second exhaust passes through a filter for removing particulate matter contained in the exhaust before the second exhaust is introduced into the catalyst. Only the seventh device is different.

As in the drawing referred to in the fifth device (FIG. 8), in FIG. 13, the exhaust gas that has passed through the exhaust gas temperature adjusting means is displayed as belonging to either the first exhaust gas or the second exhaust gas. . However, like the fifth device, this display is merely a convenience for ease of understanding. Further, like the fifth device, the ninth device does not have to be configured such that both the first exhaust and the second exhaust always exist.
The above is the description of the ninth device.

(10th Embodiment)
Next, as an example in which the concept shown in the ninth device is actually applied to an internal combustion engine, an embodiment in which “the second exhaust passes through a part of the DPF as an intermediate member” will be described. Hereinafter, the exhaust emission control device in this embodiment is also referred to as “tenth device”.

  The internal combustion engine to which the tenth device is applied is shown in the second device except that the other end of the bypass passage 46 in FIG. 2 is connected to the exhaust passage at a position where the intermediate member (DPF) is provided. The engine 10 has the same configuration as that of the engine 10. Therefore, a specific description of each member constituting the internal combustion engine to which the tenth device is applied (hereinafter also referred to as “engine 10” for convenience) is omitted as necessary.

  FIG. 14 is a schematic diagram illustrating a part of the exhaust passage (from the turbine 52 to the catalyst 45) in the tenth device. As shown in FIG. 14, the other end of the bypass passage 46 is connected to the exhaust passage at a position where the DPF 44 is provided.

  Specifically, the other end of the bypass passage 46 is connected to the exhaust passage so that the second exhaust flows into the DPF 44 in the vicinity of the downstream end of the DPF 44. Thereby, the second exhaust gas is introduced into the catalyst 45 after passing through a part of the DPF 44.

  With the above configuration, the amount of particulate matter contained in the exhaust gas introduced into the catalyst 45 is reduced. As a result, it is possible to prevent the performance of the catalyst 45 from being deteriorated by the particulate matter and that the particulate matter passes through the catalyst 45 and is released to the outside of the engine 10.

As shown in each of the embodiments described above, a control valve 47 may be provided in the bypass passage 46 of the tenth device. Further, when the catalyst 45 of the tenth device is an SCR catalyst, the reducing agent supply means 48 may be provided upstream of the catalyst 45.
The above is the description of the tenth device.

(Eleventh embodiment)
Next, an embodiment in which “the second exhaust passes through the DPF provided in the bypass passage” will be described as another example in which the concept shown in the ninth device is actually applied to the internal combustion engine. Hereinafter, the exhaust emission control device in this embodiment is also referred to as “eleventh device”.

  The internal combustion engine to which the eleventh device is applied has the same configuration as the engine 10 shown in the second device, except that a DPF is provided in the bypass passage 46 in FIG. Therefore, a specific description of each member constituting the internal combustion engine to which the eleventh device is applied (hereinafter also referred to as “engine 10” for convenience) is omitted as necessary.

  FIG. 15 is a schematic diagram illustrating a part of the exhaust passage (from the turbine 52 to the catalyst 45) in the eleventh device. As shown in FIG. 15, a DPF 49 different from the DPF 44 as an intermediate member is provided in the bypass passage 46.

  Note that the ability of the DPF 49 provided in the bypass passage 46 to remove particulate matter in the exhaust may be lower than the ability of the DPF 44 as an intermediate member to remove particulate matter in the exhaust (so-called low capacity). It may be a filter.)

  With the above configuration, the performance of the catalyst 45 is reduced by the particulate matter, and the particulate matter passes through the catalyst 45 and is released to the outside of the engine 10 as in the tenth device described above. It can be prevented.

As shown in each of the embodiments described above, a control valve 47 may be provided in the bypass passage 46 of the eleventh device. Further, when the catalyst 45 of the eleventh device is an SCR catalyst, the reducing agent supply means 48 may be provided upstream of the catalyst 45.
The above is the description of the eleventh device.

<Summary of Embodiment>
As described with reference to FIGS. 1 to 15, the exhaust purification device (first device to eleventh device) according to the embodiment of the present invention is provided in the exhaust passage (exhaust pipe 42 and others) of the internal combustion engine 10. And an exhaust temperature adjusting means (electric heater) 43 for adjusting the temperature of the exhaust gas discharged from the combustion chamber of the engine 10 and the exhaust passage provided at a position downstream of the exhaust temperature adjusting means 43 in the exhaust passage. And a catalyst 45 for purifying gas.

This exhaust purification device
After at least a part of the exhaust gas that has passed through the exhaust temperature adjusting means 43 passes through at least a part of the intermediate member 44 provided at a position between the exhaust temperature adjusting means 43 and the catalyst 45 in the exhaust passage, Can be introduced into the catalyst 45 as a first exhaust;
At least a part of the exhaust gas that has passed through the exhaust gas temperature adjusting means 43 can be introduced into the catalyst 45 as a second exhaust gas without passing through at least a part of the intermediate member 44.
(See FIGS. 1 to 5).

Furthermore, an exhaust emission control device (for example, a third device) according to one or more embodiments of the present invention includes:
The second exhaust amount is adjusted based on the temperature of at least one of the catalyst 45 and the intermediate member 44 (see FIG. 6).

Furthermore, an exhaust emission control device (for example, the second device) according to one or more embodiments of the present invention includes:
A bypass passage 46 through which the second exhaust gas passes, wherein one end of the bypass passage 46 is a position where the exhaust temperature adjusting means 43 is provided or a position downstream of the exhaust temperature adjusting means 43; A position upstream of the intermediate member 44 or a position where the intermediate member 44 is provided is connected to the exhaust passage, and the other end of the bypass passage 46 is a position where the intermediate member 44 is provided or The second exhaust gas passes through a bypass passage 46 connected to the exhaust passage at a position downstream of the intermediate member 44 and upstream of the catalyst 45 or at a position where the catalyst 45 is provided. Is introduced into the catalyst 45 (see FIGS. 2 to 5).

In addition, an exhaust emission control device (for example, a fourth device) according to one or more embodiments of the present invention includes:
A control valve 47 for adjusting the amount of the second exhaust passing through the bypass passage 46, the control valve 47 changing the amount of the second exhaust according to the opening degree of the control valve 47, Provided in the passage 46,
The opening degree of the control valve 47 is changed based on the temperature of at least one of the catalyst 45 and the intermediate member 44 (see FIG. 7).

An exhaust emission control device (for example, a first device to a fifth device) according to one or more embodiments of the present invention includes:
The catalyst 45 is configured to be a catalyst (for example, NOx occlusion reduction catalyst, SCR catalyst) 45 that purifies the exhaust gas by reducing nitrogen oxides contained in the exhaust gas.

An exhaust emission control device (for example, the fifth device and the sixth device) according to one or more embodiments of the present invention includes:
A reducing agent supply means 48 is provided to supply a reducing agent into the exhaust gas introduced into the catalyst 45 (see FIGS. 8 to 10).

An exhaust emission control device (for example, a sixth device) according to one or more embodiments of the present invention includes:
Before the second exhaust is introduced into the catalyst 45, the second exhaust passes through a position where the reducing agent supply means 48 is provided (FIGS. 9 and 9). 10).

An exhaust emission control device (for example, the seventh device and the eighth layer) according to one or more embodiments of the present invention includes:
The amount of the second exhaust is adjusted based on the temperature of at least one of the catalyst 45, the intermediate member 44, and the reducing agent supply means 48 (see FIGS. 11 and 12). .)

An exhaust emission control device (for example, a ninth device) according to one or more embodiments of the present invention includes:
Before the second exhaust is introduced into the catalyst 45, the second exhaust passes through a filter 44 for removing particulate matter contained in the exhaust (FIG. 13). See).

Specifically, an exhaust emission control device (for example, a tenth device) according to one embodiment
The intermediate member 44 includes a filter 44 for removing particulate matter contained in the exhaust, and the second exhaust passes through at least a part of the filter 44 (see FIG. 14). .)

Furthermore, the exhaust emission control device (for example, the eleventh device) according to one embodiment includes:
The bypass passage 46 is provided with a filter 44 for removing particulate matter contained in the exhaust, and the second exhaust is introduced into the catalyst 45 through the bypass passage 46 (FIG. 15).

  The present invention is not limited to the above embodiments, and various modifications can be adopted within the scope of the present invention.

  For example, the concept of the exhaust gas purification device applied to “one embodiment” of the plurality of embodiments (first embodiment to eleventh embodiment) is changed to “others” of the plurality of embodiments. The concept of the exhaust purification device in “one or more of the embodiments” may be applied. In other words, one embodiment of the plurality of embodiments may be combined with one or more other embodiments.

  Further, in the above embodiments, the members (for example, the electric heater 43 and the DPF 44) constituting the exhaust purification device are disposed in the exhaust passage in a state of being separated from each other independently (for example, FIG. 2). reference.). However, these members do not necessarily have to be arranged as such, and may be arranged in the exhaust passage in a state of being connected to each other (integrated state).

  In addition, in the above embodiments, only the DPF 44 is employed as the intermediate member. However, the intermediate member is not necessarily limited to the DPF 44, and may be configured to include other members different from the DPF. For example, an oxidation catalyst that can oxidize nitrogen oxides contained in the exhaust can be employed as the intermediate member. When a plurality of members are employed as the intermediate member, the plurality of members may be arranged in a state of being separated from each other or may be arranged in an integrated state.

  As described above, the present invention can be used as an exhaust purification device applied to an internal combustion engine having a catalyst for purifying exhaust gas in an exhaust passage.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 43 ... Electric heater, 44 ... Diesel particulate filter, 45 ... Catalyst, 80 ... Electronic control unit

Claims (11)

An exhaust temperature adjusting means that is provided in an exhaust passage of the internal combustion engine and adjusts the temperature of exhaust discharged from the combustion chamber of the internal combustion engine;
A catalyst provided at a position downstream of the exhaust temperature adjusting means in the exhaust passage and purifying the exhaust;
With
After at least a part of the exhaust gas that has passed through the exhaust temperature adjusting means passes through at least a part of an intermediate member provided at a position between the exhaust temperature adjusting means and the catalyst in the exhaust passage, Can be introduced into the catalyst;
At least a part of the exhaust gas that has passed through the exhaust gas temperature adjusting means can be introduced into the catalyst as a second exhaust gas without passing through at least a part of the intermediate member.
An exhaust emission control device for an internal combustion engine configured as described above. The exhaust emission control device according to claim 1,
An exhaust emission control device in which the amount of the second exhaust gas is adjusted based on the temperature of at least one of the catalyst and the intermediate member. The exhaust emission control device according to any one of claims 1 and 2,
A bypass passage through which the second exhaust gas passes, wherein one end of the bypass passage is a position where the exhaust temperature adjusting means is provided or a position downstream of the exhaust temperature adjusting means and more than the intermediate member The bypass passage is connected to the exhaust passage at an upstream position or a position where the intermediate member is provided, and the other end of the bypass passage is located downstream of the intermediate member or the position where the intermediate member is provided. An exhaust emission control device, wherein the second exhaust gas is introduced into the catalyst through a bypass passage connected to the exhaust passage at a position that is upstream of the catalyst or at a position where the catalyst is provided. The exhaust emission control device according to claim 3,
A control valve for adjusting the amount of the second exhaust that passes through the bypass passage, the control valve changing the amount of the second exhaust according to the opening of the control valve, is provided in the bypass passage. ,
An exhaust emission control device in which an opening degree of the control valve is changed based on a temperature of at least one of the catalyst and the intermediate member. The exhaust emission control device according to any one of claims 1 to 4,
An exhaust emission control device, wherein the catalyst is a catalyst that purifies the exhaust gas by reducing nitrogen oxides contained in the exhaust gas. An exhaust emission control device according to claim 5,
An exhaust emission control device comprising a reducing agent supply means for supplying a reducing agent into the exhaust gas introduced into the catalyst. The exhaust emission control device according to claim 6,
The exhaust gas purification apparatus, wherein the second exhaust gas passes through a position where the reducing agent supply means is provided before the second exhaust gas is introduced into the catalyst. The exhaust emission control device according to claim 6 or 7,
An exhaust emission control device in which the amount of the second exhaust gas is adjusted based on the temperature of at least one of the catalyst, the intermediate member, and the reducing agent supply means. The exhaust emission control device according to any one of claims 1 to 8,
The exhaust emission control device, wherein the second exhaust gas passes through a filter for removing particulate matter contained in the exhaust gas before the second exhaust gas is introduced into the catalyst. The exhaust emission control device according to any one of claims 1 to 9,
The intermediate member includes a filter for removing particulate matter contained in the exhaust;
The exhaust emission control device, wherein the second exhaust gas passes through at least a part of the filter. The exhaust emission control device according to any one of claims 3 to 10,
A filter for removing particulate matter contained in the exhaust is provided in the bypass passage,
The exhaust emission control device, wherein the second exhaust gas is introduced into the catalyst through the bypass passage.

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