JP2012082708A - Exhaust gas control apparatus, and internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately heat or combust fuel added to an exhaust passage regardless of variations in the state of exhaust gas in the exhaust passage.SOLUTION: An exhaust gas control apparatus includes: a fuel adding means 34 that is provided so as to supply fuel to an exhaust passage, which is upstream of exhaust gas purification members 20, 22, 24 provided in the exhaust passage 14; a heating means 36 that is disposed between the fuel adding means 34 and the exhaust gas purification member; and a control means that controls an amount of electric power that is supplied to the heating portion 36, based on an exhaust gas temperature and an exhaust gas flow rate.

Description

  The present invention relates to an exhaust emission control device for purifying exhaust gas and an internal combustion engine including the same.

  Patent Document 1 discloses an example of an exhaust purification device for an internal combustion engine. This exhaust purification device includes a small oxidation catalyst, a fuel supply valve, and a glow plug disposed between them in an exhaust passage upstream of the exhaust purification catalyst. The injection port of the fuel supply valve faces the end face of the small oxidation catalyst, and the glow plug is disposed at a position where the tip of the glow plug comes into contact with the fuel injected from the fuel supply valve. Each operation of the fuel supply valve and the glow plug is controlled and they may have first to third control states. In the first control state, heating by the glow plug is performed while fuel is supplied from the fuel supply valve, and the fuel from the fuel supply valve is ignited. In the second control state, the glow plug is heated while fuel is supplied from the fuel supply valve, but the fuel from the fuel supply valve is not ignited. In the third control state, fuel is supplied from the fuel supply valve, but heating by the glow plug is stopped. The first control state or the third control state can be selected in an operation region where ignition is possible, and the second control state or the third control state can be selected in an operation region where ignition is impossible.

JP 2010-059886 A

  By the way, in the exhaust emission control device described in Patent Document 1, since the glow plug is provided in the exhaust passage, heating by the glow plug can be influenced by the exhaust. For example, the degree of cooling of the glow plug by exhaust varies depending on the exhaust temperature. However, in order to appropriately control the temperature of the exhaust purification catalyst, it is desirable to heat or burn the fuel added to the exhaust passage in the same manner even when the exhaust temperature is different.

  Therefore, the present invention has been devised in view of such a point, and an object thereof is to appropriately heat or burn the fuel added to the exhaust passage even when the exhaust state of the exhaust passage is different. It is in.

  The present invention includes an exhaust purification member provided in an exhaust passage, fuel addition means provided so as to supply fuel to an exhaust passage upstream of the exhaust purification member, the fuel addition means and the exhaust Provided is an exhaust emission control device comprising a heating means disposed between a purification member and a control means for controlling the amount of electric power supplied to the heating means based on an exhaust temperature and an exhaust flow rate.

  The control means may increase the amount of power supplied to the heating means as the exhaust temperature is lower.

  The control means may increase the amount of power supplied to the heating means as the exhaust gas flow rate increases.

  The control means may correct and control the amount of power supplied to the heating means based on the amount of fuel added from the fuel addition means. The control means may correctively control the amount of power supplied to the heating means so that the amount of power supplied to the heating means increases as the amount of fuel added from the fuel addition means increases.

  The present invention also resides in an internal combustion engine provided with the exhaust purification device as described above.

1 is a schematic configuration diagram showing an internal combustion engine to which an exhaust gas purification apparatus according to a first embodiment of the present invention is applied. It is a flowchart for demonstrating the operation control of the fuel addition valve and glow plug in 1st Embodiment. It is a flowchart for demonstrating the operation control of the fuel addition valve and glow plug in 2nd Embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view of an internal combustion engine (hereinafter referred to as an engine) 10 to which an exhaust emission control device 1 according to the first embodiment is applied. The engine 10 is a compression ignition internal combustion engine for automobiles, that is, a diesel engine. In FIG. 1, a part of the exhaust system extending from the engine body 10 ′ is exaggerated (intake system and engine). Internal mechanisms are omitted).

  A first catalytic converter 16 and a second catalytic converter 18 are provided in series in the exhaust passage 14 defined by the exhaust pipe 12 of the engine 10 in order from the upstream side. In the first catalytic converter 16, a first exhaust purification member (hereinafter referred to as a first purification member) 20 and a second exhaust purification member (hereinafter referred to as a second purification member) 22 are accommodated in series. Yes. A second exhaust purification member (hereinafter referred to as a third purification member) 24 is accommodated in the second catalytic converter 18. The first purification member 20, the second purification member 22, and the third purification member 24 are included in the exhaust purification device 1.

  Here, the first purification member 20 includes an oxidation catalyst. The first purification member 20 is formed as a monolith catalyst carrying a noble metal catalyst such as platinum Pt.

  The second purification member 22 is a particulate filter for collecting particulate matter (PM) in the exhaust gas. The particulate filter that is the second purification member 22 does not carry a noble metal catalyst. However, a noble metal catalyst such as platinum Pt can be supported on the particulate filter.

  The third purification member 24 includes a NOx purification catalyst, here, a NOx storage reduction catalyst. In the third purification member 24, a catalyst carrier made of alumina, for example, is supported on the base. A noble metal catalyst such as platinum Pt is dispersed and supported on the surface of the catalyst carrier, and a layer of NOx absorbent is formed on the surface of the catalyst carrier. The NOx absorbent occludes NOx when the air-fuel ratio of the exhaust gas is lean, and performs NOx absorption / release action to release the stored NOx when the oxygen concentration in the exhaust gas decreases. The third purifying member 24 stores NOx when the air-fuel ratio of the exhaust gas is lean, and releases the stored NOx when the oxygen concentration in the exhaust gas decreases, for example, when the air-fuel ratio of the exhaust gas becomes rich. NOx is reduced. The third purification member 24 can include a NOx purification catalyst that promotes a chemical reaction (reduction reaction) between ammonia and NOx. In this case, for example, a urea water addition device may be provided between the first converter 16 and the second converter 18 for supplying ammonia.

  Now, the exhaust emission control device 1 provided in the engine 10 further includes a temperature control device 30. The temperature control device 30 is provided to control the temperature of the exhaust purification members 20, 22, and 24, specifically to heat them. The temperature control device 30 generates a heating gas and supplies it to the first to third purification members 20, 22, 24, particularly the second purification member 22 and the third purification member 24 on the downstream side, and these exhaust purification members. This is for maintaining or promoting the warming-up or heating and its active state.

  In particular, here, the temperature control device 30 heats the third purification member 24 of the three exhaust purification members to a temperature within a predetermined activation temperature range of the third purification member 24, which is within the predetermined activation temperature range. To continue to have a temperature of In addition, the temperature control device 30 operates at a predetermined time for a predetermined time in order to remove the PM collected by the second purification member 22. For example, the temperature control device 30 operates every time the cumulative operation time of the engine 10 exceeds a predetermined time. The temperature control device 30 can also work when the differential pressure before and after the second purification member 22 exceeds a predetermined pressure. In this case, a pressure sensor for detecting the differential pressure before and after the second purification member 22, that is, a differential pressure sensor may be provided.

  The temperature control device 30 includes an oxidation promotion member 32, a fuel addition valve 34, and a glow plug 36 that are provided upstream of the above-described exhaust purification member. The glow plug 36 is positioned downstream of the fuel addition valve 34. The oxidation promotion member 32 and the fuel addition valve 34 are arranged so that fuel can be injected from the fuel addition valve 34 toward the oxidation promotion member 32. Further, the fuel addition valve 34 and the glow plug 36 are arranged so that fuel can be injected from the fuel addition valve 34 toward the tip end portion 36a which is a heating portion of the glow plug 36. That is, the fuel addition valve 34 is provided so as to supply fuel upstream from the glow plug 36.

  The oxidation promoting member 32 includes a catalyst having an oxidation function, specifically, includes an oxidation catalyst, and includes a catalyst member 32a formed as a metal catalyst supporting a noble metal catalyst such as platinum Pt. . Such a catalyst member 32a of the oxidation promoting member 32 is fixedly supported in the exhaust passage 14 by a support member (partially not shown) including a cylindrical member 32b. However, the oxidation promoting member 32 has a size and shape determined so as not to hinder the flow of exhaust gas in the exhaust passage 14. The oxidation promoting member 32, particularly the catalyst member 32a, is smaller than the exhaust purification member such as the first purification member 20, and may be referred to as a small oxidation catalyst.

  The fuel addition valve 34 is provided as a fuel addition means. The fuel addition valve 34 can be provided so that its injection port is positioned directly in the exhaust passage. Here, the fuel addition valve 34 is provided so as to protrude from the exhaust passage 14 (hereinafter referred to as fuel passage). 37). The fuel passage 37 is a passage for guiding the fuel added from the fuel addition valve 34 to the exhaust passage 14, and particularly the fuel addition valve 34 toward the tip portion 36 a of the glow plug 36 and the catalyst member 32 a of the oxidation promoting member 32. Designed to guide the added fuel from. The fuel addition valve 34 is provided so as to add and supply the fuel pumped by the pump 40 from the fuel tank 38 included in the fuel supply device provided with the fuel injection valve of the engine body 10 ′ to the exhaust passage. Therefore, here, the fuel addition valve 34, the fuel tank 38, and the pump 40 are included in the fuel addition device 42. However, the fuel addition device 42 includes a part of a control device which will be described later and functions as control means for controlling the operation of the fuel addition valve 34 and the pump 40. The fuel injection pressure of the fuel addition valve 34 can be variable, but is constant in this embodiment. The pump 40 operates so that the injection pressure of the fuel addition valve 34 is constant. The fuel addition device 42 includes a mechanism that returns excess fuel to the fuel tank 38. However, the fuel addition valve 34 can also be configured completely independently of the fuel supply device.

  The glow plug 36 is provided as a heating means. When the glow plug 36 is energized, the tip portion 36a, which is the heating portion of the glow plug 36, generates heat and can heat the exhaust gas and the fuel added from the fuel addition valve 34. A glow plug 36 as a heating means is included in the heating device 44. The heating device 44 includes a part of a control device which will be described later and functions as control means for controlling the operation of the glow plug 36, that is, heat generation. The control means included in the heating device 44 controls the operation of the glow plug 36, that is, the energization of the glow plug 36. Specifically, the control means included in the heating device 44 controls the amount of power supplied to the glow plug 36 by controlling a glow plug control unit (hereinafter referred to as GCU) 46, and generates heat at the tip 36a. Control the amount. The GCU 46 is provided to control the duty ratio in the duty control for the glow plug 36. By controlling the GCU 46, the voltage applied to the glow plug 36 is constant, but the duty ratio can be changed, and as a result, the amount of power supplied to the glow plug 36 can be changed. The GCU 46 and the glow plug 36 are connected via a power supply 48. However, in the case of providing a configuration in which the magnitude of the voltage applied to the glow plug 36 is variable, for example, the amount of power supplied to the glow plug 36 may be changed by changing the magnitude of the voltage applied to the glow plug 36. . In place of the glow plug 36, a ceramic heater may be used as a heating means.

  The fuel injected from the fuel addition valve 34 can pass around the tip portion 36a of the glow plug 36 and reach the oxidation promoting member 32 and its surroundings. When the tip portion 36a generates heat by energization of the glow plug 36, the fuel receives heat from the glow plug 36 and burns depending on the case, and reaches the oxidation promoting member 32 and its surroundings. The oxidation promoting member 32 promotes oxidation of the fuel, for example, combustion. In particular, since the oxidation promotion member 32 includes an oxidation catalyst here, the oxidation promotion member 32 promotes the oxidation of fuel more suitably when the temperature of the oxidation promotion member 32 is within the predetermined activation temperature range. Note that the oxidation of the oxidation promoting member 32 itself increases due to the oxidation of the fuel in the oxidation promoting member 32, and thus the oxidation promoting member 32 is heated. Thus, the heating gas is generated and flows to the exhaust purification members 20, 22, 24. Such a heating gas can have a high temperature due to the oxidation of the fuel.

  Such a heating gas may contain reformed fuel. When the temperature of the oxidation promoting member 32 is increased, hydrocarbons having a large number of carbon atoms in the unburned fuel are decomposed by the oxidation promoting member 32 to generate hydrocarbons having a low carbon number and high reactivity. It is reformed to a highly efficient fuel. In other words, the oxidation promoting member 32 constitutes a rapid heat generator that rapidly generates heat on the one hand, and a reformed fuel discharger that discharges the reformed fuel on the other hand. Note that when the fuel is added from the fuel addition valve 34 so as to generate such reformed fuel, the glow plug 36 may not be heated.

  The operation of the fuel addition valve 34 and the glow plug 36 is controlled by a control device 50 having a function as a control means for controlling the operation of the fuel addition valve 34 and the glow plug 36 according to the engine operating state, the temperature of the exhaust purification member, and the like. Is done. These operating states are roughly divided into the following two states. There is a first operating state where fuel is added from the fuel addition valve 34 and heated by the glow plug 36 to promote combustion or reforming of the fuel. In addition, there is a second operating state in which fuel addition is performed from the fuel addition valve 34 but heating by the glow plug 36 is stopped. There is also a state where the fuel addition is not performed (third operation state) until the tip portion 36a of the glow plug 36 generates heat to some extent. However, normally, the fuel addition valve 34 and the glow plug 36 are maintained in an inoperative state.

  The engine 10 having such a configuration includes, in the control device 50, various sensors that electrically output signals for detecting (including estimating) various values. Here, some of them will be specifically described. An engine speed sensor 52 for detecting the engine speed is provided. An engine load sensor 54 for detecting the engine load is also provided. As the engine load sensor 54, a throttle opening sensor, an accelerator opening sensor, an air flow meter, an intake pressure sensor, or the like can be used. Further, a flow rate sensor 56 for detecting the flow rate of exhaust gas, that is, the flow velocity in the exhaust passage 14 is provided. As the flow sensor 56, an air flow meter for detecting the amount of intake air provided in the intake passage can be used. Although not shown, an oxygen concentration sensor for detecting the oxygen concentration in the exhaust, a NOx sensor for detecting the NOx amount in the exhaust, and the like are provided. A first temperature sensor 58 for detecting the temperature of the exhaust gas in the exhaust passage 14 is provided. Furthermore, a second temperature sensor 60 for detecting the temperature of the third purification member 24 is provided.

  The control device 50 includes a microcomputer including a CPU, a storage device (for example, ROM, RAM), an A / D converter, an input interface, an output interface, and the like. The various sensors are electrically connected to the input interface. Based on output signals or detection signals from these various sensors, the control device 50 is electrically operated or driven from the output interface so that the engine 10 can be smoothly operated or operated in accordance with a preset program or the like. Output a signal. Thus, the operation of the fuel injection valve, the operation of the fuel addition valve 34, the operation of the glow plug 36 (energization to the glow plug 36), the operation of the pump 40, and the like are controlled.

  The control device 50 has a control function of the engine 10 in general, and has a function of a control means (control device) in the temperature control device 30. That is, fuel addition control means for controlling the operation of the fuel addition valve 34 as fuel addition means, heat generation control means or heating control means for controlling the operation of the glow plug 36 as heating means, and pump control for controlling the operation of the pump 40. As each of the means, a part of the control device 50 can function. The exhaust state detection device for detecting the exhaust state in the exhaust passage 14, that is, the exhaust state, here is an exhaust temperature detection device including the first temperature sensor 58 as exhaust temperature detection means and a part of the control device 50. And an exhaust flow rate detecting device including the flow rate sensor 56 serving as an exhaust flow rate detecting means and a part of the control device 50.

  In the engine 10, a fuel injection amount (fuel amount), a fuel injection timing, and the like are obtained so as to obtain a desired output based on an intake air amount, an engine rotational speed, etc., that is, an engine operating state represented by an engine load and an engine rotational speed. Is set. Based on the fuel injection amount and the fuel injection timing, fuel is injected from the fuel injection valve.

  In the temperature control device 30, for example, when the engine is started, the temperature of the third purification member 24 is set to a predetermined activity of the third purification member 24 so that the temperature of the exhaust purification member rises earlier than a predetermined temperature. The fuel addition valve 34 and the glow plug 36 are operated so as to reach the temperature range early. That is, the glow plug 36 is energized, and fuel is injected from the fuel addition valve 34 toward the tip portion 36a. The gas containing or generated due to this fuel passes through the oxidation promoting member 32 and its surroundings and reaches the exhaust purification member. The gas supply to the exhaust purification member at the time of starting the engine is performed from the start of the engine start until the temperature of the third purification member 24 becomes equal to or higher than a predetermined temperature within the predetermined active temperature range. Here, the predetermined temperature within the predetermined activation temperature range of the third purification member is the lower limit temperature of the predetermined activation temperature range, and is set to 200 ° C., for example. However, the supply of the heating gas to the exhaust gas purification member at the time of starting the engine may be continued until the engine warm-up is completed even if the temperature of the exhaust gas purification member is raised early. In this case, completion of engine warm-up is determined based on the coolant temperature of the engine 10. For example, when the temperature of the exhaust purification member rises early and then the cooling water temperature of the engine 10 becomes equal to or higher than a predetermined temperature (for example, 70 ° C.), the control device 50 determines that the engine warm-up is complete. Both the operation of the fuel addition valve 34 and the operation of the glow plug 36 are stopped.

  Furthermore, after the temperature of the third purification member 24 reaches the above-described predetermined activation temperature range, the temperature control device 30 functions to keep the temperature of the third purification member 24 within the predetermined activation temperature range. Specifically, when the temperature of the third purification member 24 is within a lower limit temperature range (for example, a temperature range of 200 ° C. or more and 250 ° C. or less) within the predetermined activation temperature range, fuel is added from the fuel addition valve 34 and glow The plug 36 is energized (the glow plug is activated).

  When it is necessary to supply the heating gas in this way, the fuel addition valve 34 and the glow plug 36 are operated. Here, in order to heat the fuel added from the fuel addition valve 34 more appropriately, the glow addition valve 34 and the glow plug 36 are used here. The exhaust state, that is, the exhaust state is considered in the operation control of the plug 36. Depending on the exhaust state in the exhaust passage 14, the cooling method of the glow plug 36 may change. This means that the heat generation or heating action of the glow plug 36 changes depending on the exhaust state. For example, the lower the exhaust temperature, the easier the glow plug 36 is cooled by the exhaust. Further, the larger the amount of intake air, that is, the larger the exhaust flow rate, the faster the exhaust flow velocity around the glow plug 36, and the glow plug 36 is easily cooled by the exhaust. Therefore, as described below, the amount of power supplied to the glow plug 36 is controlled in accordance with the exhaust state.

  The fuel addition control from the fuel addition valve 34 and the heating control by the glow plug 36 will be described with reference to the flowchart of FIG. However, the flowchart of FIG. 2 is repeated every predetermined time.

  The control device 50 determines whether or not the exhaust purification member needs to be heated (step S201). When the exhaust purification member needs to be heated, here, as described above, when the engine is started, when the temperature of the exhaust purification member is low or likely to be low as described above, and the second purification member 22 is used. It includes the time to remove the PM collected in the. In such a case, it is determined that the exhaust purification member needs to be heated (positive determination in step S201).

  When the exhaust purification member needs to be heated (Yes in step S201), the output of the first temperature sensor 58 and the output of the flow sensor 56 are acquired (step S203). This means that the exhaust temperature and the exhaust flow rate are detected.

  Based on the acquired output, the amount of power supplied to the glow plug 36 is calculated (step S205). This means obtaining the amount of power supplied to the glow plug 36 based on the exhaust temperature and the exhaust flow rate. Here, the calculation of the power supply amount is performed based on mapped data that is obtained and set in advance by experiments or the like. However, the calculation of the power supply amount may be performed based on an arithmetic expression obtained and set in advance by experiments or the like, or may be performed based on both such data and the arithmetic expression. Such data and arithmetic expressions follow a first relationship in which the amount of power supplied to the glow plug 36 is increased as the exhaust temperature is lower and a second relationship in which the amount of power supplied to the glow plug 36 is increased as the exhaust flow rate is increased. As described above, the calculation of the amount of power supplied to the glow plug 36 is based on the engine state, the temperature of the exhaust purification member, and the like.

  The operation of the glow plug 36 is controlled based on the obtained power supply amount (step S207). At this time, the fuel addition valve 34 is also operated (step S207). However, the amount of fuel added from the fuel addition valve 34 may be variable, but is constant here. For example, the amount of fuel added from the fuel addition valve 34 can be changed based on the temperature of the exhaust purification member. In addition, by the operation control of the fuel addition valve 34 and the glow plug 36 in step S207, they can be brought into the first operation state or the second operation state.

  On the other hand, when heating of the exhaust purification member is not necessary (No in Step S201), the operations of both the fuel addition valve 34 and the glow plug 36 are stopped (Step S209). That is, they are deactivated.

  As described above, when fuel is added from the fuel addition valve 34, the amount of power supplied to the glow plug 36 is variably controlled based on the exhaust state, particularly the exhaust temperature and the exhaust flow rate. Therefore, it becomes possible to appropriately heat or burn the added fuel regardless of the exhaust state. Further, since the amount of power supplied to the glow plug 36 is controlled in this way, the total amount of power supplied to the glow plug 36 can be suppressed. Therefore, fuel consumption can be improved by reducing power consumption.

  Next, a second embodiment of the present invention will be described. The exhaust purification device 101 according to the second embodiment is applied to an engine in the same manner as the exhaust purification device 1 according to the first embodiment described above. However, the exhaust purification device 101 according to the second embodiment is different from the exhaust purification device 1 according to the first embodiment in terms of operation control of the fuel addition valve 34 and the glow plug 36. Therefore, the difference will be mainly described below. However, since the configuration of the exhaust gas purification apparatus 101 according to the second embodiment is substantially the same as the configuration of the exhaust gas purification apparatus 1 according to the first embodiment, the components corresponding to those already described are already described. The same reference numerals as those of the above-described components are attached, and the duplicate description is omitted.

  Although the control in the second embodiment will be described below, the amount of power supplied to the glow plug 36 is controlled based on the exhaust state and the amount of fuel added. This is because the glow plug 36 can be cooled by the fuel added from the fuel addition valve 34, and the heat generation or heating action can change depending on the amount of fuel added.

  The control device 50 first determines whether or not the exhaust purification member needs to be heated as in step S201 (step S301). When the exhaust purification member needs to be heated (Yes in step S301), the output of the first temperature sensor 58 and the output of the flow rate sensor 56 are acquired in the same manner as in step S203 (step S303). Based on this output, the reference power amount applied to the glow plug 36 is calculated (step S305). The calculation of the reference power amount corresponds to the calculation of the supplied power amount in step S205.

  Further, the control device 50 calculates the amount of fuel added from the fuel addition valve 34 (step S307). This is executed based on the result of the heating determination in step S301 and based on data or the like obtained and set in advance through experiments or the like. Specifically, when the temperature of the third purification member 24 is to be increased to the predetermined temperature, the fuel addition amount is calculated, and when the PM removal of the second purification member 22 is intended, the fuel addition amount is calculated. . Note that the calculation of the fuel addition amount in step S307 can be performed more precisely based on the engine operating state, the temperature of the exhaust purification member and / or the exhaust state, and the like.

  And the part which functions as the correction coefficient calculation means of the control apparatus 50 calculates a correction coefficient (step S309). This correction coefficient is calculated based on the output of the first temperature sensor 58 acquired in step S303 and the fuel addition amount calculated in step S307. This means that the correction coefficient is obtained based on the exhaust temperature and the fuel addition amount. Here, the calculation of the correction coefficient is performed based on mapped data obtained and set in advance by experiments or the like. However, the calculation of the correction coefficient may be performed based on an arithmetic expression obtained and set in advance by experiments or the like, or may be performed based on both such data and the arithmetic expression. Such data and arithmetic expressions follow a third relationship in which the amount of power supplied to the glow plug 36 is increased as the exhaust temperature is lower, and a fourth relationship in which the amount of power supplied to the glow plug 36 is increased as the amount of fuel added is increased. . The correction coefficient can be calculated based only on the fuel addition amount calculated in step S307.

  Based on the reference power amount obtained in step S305 and the correction coefficient obtained in step S309, the power supply amount to the glow plug 36 is calculated (step S311). Here, the amount of power supplied to the glow plug 36 is calculated from the product of the reference power amount and the correction coefficient.

  As a result, the operation of the fuel addition valve 34 and the glow plug 36 is controlled based on the fuel addition amount obtained in step S307 and the supplied power amount obtained in step S311 (step S313). In addition, by the operation control of the fuel addition valve 34 and the glow plug 36 in step S313, they can be brought into the first operation state or the second operation state.

  On the other hand, when heating of the exhaust purification member is not necessary (No in Step S301), the operation of both the fuel addition valve 34 and the glow plug 36 is stopped (Step S315).

  As mentioned above, although this invention was demonstrated based on two embodiment, this invention is not limited to them, Other embodiment is accept | permitted. For example, in the above embodiment, the sensor is used for detecting the exhaust temperature and the exhaust flow rate. However, the detection, that is, the estimation may be performed based on the engine operating state or the like. Further, the temperature of the exhaust purification member may also be detected, that is, estimated based on the engine operating state or the like.

  In the above embodiment, the fuel addition valve is used as the fuel addition means, and the same fuel as the fuel of the internal combustion engine is added from the fuel addition valve. However, other fuels can be used, for example, alcohols such as ethanol and methanol can be used as additives.

  Further, the number, type, configuration, and arrangement order of the exhaust purification members provided in the exhaust passage are not limited to the above embodiment. The number of exhaust purification members may be one, two, or four or more. For example, an exhaust purification member including an oxidation catalyst may be further provided downstream of the third purification member. Various catalysts, filters, and the like can be used as the exhaust purification member. Moreover, the oxidation promoting member may not include the oxidation catalyst having the above-described configuration, and may include a catalyst having another oxidation function. Note that the oxidation promoting member may not be provided.

  In the above embodiment, the present invention is applied to a diesel engine. However, the present invention is not limited to this, and the present invention can be applied to various engines such as a port injection type gasoline engine and a cylinder injection type gasoline engine. It is. The fuel used is not limited to light oil or gasoline, but may be alcohol fuel, LPG (liquefied natural gas), or the like. Further, the number of cylinders and the cylinder arrangement format of the engine to which the present invention is applied may be any.

  Moreover, the exhaust emission control device according to the present invention is applicable to technologies other than the engine. For example, the present invention can be used for plant equipment.

  It should be understood that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as set forth in the claims. That is, the present invention includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims.

DESCRIPTION OF SYMBOLS 1 Exhaust purification device 10 Internal combustion engine 14 Exhaust passage 20 First exhaust purification member (first purification member)
22 Second exhaust purification member (second purification member)
24 Third exhaust purification member (third purification member)
30 Temperature control device 32 Oxidation promoting member 34 Fuel addition valve 36 Glow plug 42 Fuel addition device 44 Heating device

Claims (6)

An exhaust purification member provided in the exhaust passage;
Fuel addition means provided to supply fuel to the exhaust passage upstream of the exhaust purification member;
Heating means disposed between the fuel addition means and the exhaust purification member;
An exhaust emission control device comprising: control means for controlling an amount of electric power supplied to the heating means based on an exhaust gas temperature and an exhaust gas flow rate.   The exhaust emission control device according to claim 1, wherein the control means increases the amount of electric power supplied to the heating means as the exhaust gas temperature is lower.   3. The exhaust emission control device according to claim 1, wherein the control unit increases the amount of electric power supplied to the heating unit as the exhaust gas flow rate increases.   The exhaust emission control device according to any one of claims 1 to 3, wherein the control means corrects and controls the amount of electric power supplied to the heating means based on the amount of fuel added from the fuel addition means.   The control means corrects and controls the amount of power supplied to the heating means so that the amount of power supplied to the heating means increases as the amount of fuel added from the fuel addition means increases. 4. An exhaust emission control device according to 4.   An internal combustion engine comprising the exhaust emission control device according to any one of claims 1 to 5.

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