JP2018127971A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine that allows further efficient regeneration of a PM filter.SOLUTION: An exhaust emission control device 40 for an internal combustion engine includes: an oxidation catalyst 41 and a particulate filter 42 sequentially arranged toward a downstream side from an upstream side in an exhaust passage 30 of the internal combustion engine; and an exhaust pipe injector 43 for supplying fuel together with compressed air in the exhaust passage 30 closer to an upstream side than the oxidation catalyst 41.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an exhaust gas purification apparatus for an internal combustion engine.

  As an exhaust purification device that is disposed in an exhaust passage of an internal combustion engine and purifies exhaust gas, an exhaust purification device in which an oxidation catalyst and a particulate filter are arranged side by side from the upstream side is known (for example, Patent Document 1). See). In such an exhaust purification device, the oxidation catalyst removes hydrocarbon (HC) and nitrogen monoxide (NCO) contained in the exhaust gas, and a particulate filter (hereinafter also referred to as “PM filter”) is contained in the exhaust gas. The PM (Particulate Matter) contained in is captured.

  In such an exhaust purification device, a process of periodically burning and removing PM accumulated in the PM filter (hereinafter referred to as “regeneration of the PM filter”) is performed. At the time of regeneration of the PM filter, the oxidation catalyst is used to oxidize HC and raise the temperature of the exhaust gas to promote regeneration of the PM filter.

JP 2005-320880 A

  By the way, in consideration of efficient regeneration of the PM filter in a short time, it is desirable to perform regeneration under conditions where the oxygen concentration in the exhaust gas and the temperature of the exhaust gas are as close to optimum as possible.

  An object of the present disclosure is to provide an exhaust purification device for an internal combustion engine that enables regeneration of the PM filter more efficiently.

  The main present disclosure for solving the above-described problems is that an oxidation catalyst and a particulate filter are sequentially disposed in an exhaust passage of an internal combustion engine from an upstream side toward a downstream side, and the exhaust passage upstream of the oxidation catalyst. And an exhaust pipe injector for supplying fuel together with pressurized air.

  According to the exhaust gas purification apparatus for an internal combustion engine according to the present disclosure, the regeneration of the PM filter can be performed more efficiently.

The figure which shows an example of a structure of the vehicle which concerns on embodiment The figure which shows an example of a structure of the exhaust pipe injector which concerns on embodiment The flowchart which shows an example of operation | movement of filter regeneration ECU which concerns on embodiment The figure which shows an example of the relationship between the oxygen concentration in exhaust gas and PM combustion speed The figure which shows an example of the relationship between the temperature of exhaust gas and PM combustion speed

[Configuration of exhaust purification system]
Hereinafter, with reference to FIG. 1, the structure of the exhaust emission control device according to an embodiment will be described.

  In the present embodiment, as an example, a mode in which the exhaust emission control device is applied to a self-ignition internal combustion engine (hereinafter also referred to as “diesel engine”) will be described. However, it is needless to say that the exhaust emission control device according to the present embodiment can be applied not only to a diesel engine but also to a gasoline engine.

  FIG. 1 is a diagram illustrating an example of a configuration of a vehicle A including an exhaust purification device 40 according to the present embodiment.

  The vehicle A according to this embodiment includes an engine body 10, an intake passage 20, an exhaust passage 30, an air cleaner 21, a turbo charger 22, an intake throttle valve 23, an external EGR device 31, an exhaust purification device 40, various sensors 51 to 53, and the like. It is comprised including.

  The engine body 10 includes a combustion chamber and a fuel injection device (not shown). In the combustion chamber, an air intake stroke, an air compression stroke, a combustion gas expansion stroke, and a combustion gas exhaust stroke are performed. By being repeatedly performed, power of the vehicle A is generated. The engine body 10 according to the present embodiment is a four-cylinder engine, and branches from the intake passage 20 to four combustion chambers via intake manifolds, and exhaust manifolds (not shown) are supplied from the four combustion chambers. Via the exhaust passage 30.

  The intake passage 20 is a flow path that draws fresh air (air) from the upstream intake port 20 a and supplies the fresh air to the engine body 10. In the intake passage 20, an air cleaner 21, a compressor of a turbocharger 22, and an intake throttle valve 23 are provided in order from the upstream intake port 20 a to the combustion chamber.

  The air cleaner 21 is supplied with air sucked from the air inlet 20a, removes impurities from the air, and sends the air to the turbocharger 22 side.

  The turbocharger 22 rotates the turbine using the pressure of the exhaust gas in the exhaust passage 30, operates the coaxial compressor by the rotational motion of the turbine, compresses the air flowing through the intake passage 20, and Send out to the main body 10 side.

  The intake throttle valve 23 adjusts the amount of air flowing through the intake passage 20.

  The exhaust passage 30 is a flow path for discharging the exhaust gas after combustion discharged from the engine body 10 to the outside of the vehicle A. In the exhaust passage 30, an external EGR device 31, a turbine of the turbocharger 22, and an exhaust purification device 40 are provided in this order from the engine body 10 toward the downstream side.

  The external EGR device 31 circulates part of the exhaust gas flowing through the exhaust passage 30 to the intake passage 20. The external EGR device 31 communicates the exhaust passage 30 and the intake passage 20 and distributes the exhaust gas exhausted from the combustion chamber to the exhaust passage 30 to the intake passage 20 side through the EGR passage 31a and the EGR passage 31a. It includes an EGR cooler 31b that cools the exhaust gas, an EGR valve 31c that adjusts the amount of exhaust gas flowing through the EGR passage 31a, and the like.

  The exhaust purification device 40 includes an oxidation catalyst 41, a PM filter 42, an exhaust pipe injector 43, and a filter regeneration ECU (Electronic Control Unit) 44.

  The oxidation catalyst 41 oxidizes and removes hydrocarbons and nitrogen monoxide of unburned fuel contained in the exhaust gas. The oxidation catalyst 41 may be any known oxidation catalyst. For example, a porous ceramic such as cordierite or silicon carbide is used, and the catalyst component is supported thereon.

  The oxidation catalyst 41 is disposed adjacent to the upstream side of the PM filter 42 in the exhaust passage 30. The oxidation catalyst 41 oxidizes unburned fuel (HC) supplied from the exhaust pipe injector 43 or unburned fuel (HC) supplied from the fuel injection device of the engine body 10 or the like when the PM filter 42 is regenerated. Then, the exhaust gas temperature is raised to a desired level (for example, about 600 degrees) for burning PM.

  The PM filter 42 captures PM contained in the exhaust gas. The PM filter 42 may be any known PM filter. For example, a porous ceramic such as cordierite or silicon carbide is used, and a honeycomb is formed so that exhaust gas passes through partition walls formed of the porous ceramic. A structure is formed.

  The exhaust pipe injector 43 injects unburned fuel (hereinafter abbreviated as “fuel” or “HC”) in the exhaust passage 30 upstream of the oxidation catalyst 41, burns the fuel, and sets the exhaust gas temperature. Raise.

  FIG. 2 is a diagram illustrating an example of the configuration of the exhaust pipe injector 43 according to the present embodiment.

  The exhaust pipe injector 43 according to the present embodiment uses pressurized air as an oxygen source (hereinafter also referred to as “secondary air”) that adjusts the atomization of fuel and the oxygen concentration in the exhaust gas.

  The exhaust pipe injector 43 includes a fuel tank 43a, a pressurized air introducing portion 43b, an injected fuel control valve 43c, a pressurized air control valve 43d, a secondary air control valve 43e, and an injector body 43f (FIG. 2). See).

  The fuel tank 43a stores fuel. The fuel in the fuel tank 43a is held in a pressurized state between the fuel tank 43a and the injected fuel control valve 43c using, for example, a supply pump.

  The pressurized air introduction part 43b introduces pressurized air into the injector body 43f. The pressurized air introduction unit 43b includes, for example, an air tank that stores pressurized air, an air pump that stores the pressurized air in the air tank, and the like.

  The injector main body 43f is an injection unit having a fuel injection passage 43fa and a secondary air passage 43fb therein. The fuel injection passage 43fa is a fuel flow path (arrow B in FIG. 2) having one end communicating with the fuel tank 43a and the other end communicating with the exhaust passage 30. Further, the fuel injection passage 43fa branches in the middle so as to communicate with the pressurized air introduction portion 43b. The injector main body 43f mixes the fuel introduced from the fuel tank 43a and the pressurized air introduced from the pressurized air introducing portion 43b in the fuel injection passage 43fa. In other words, the fuel introduced from the fuel tank 43a is mixed with the pressurized air and injected into the exhaust passage 30 while passing through the fuel injection passage 43fa in the injector body 43f.

  Further, the secondary air passage 43fb is a passage of pressurized air (an arrow C in FIG. 2) in which one end communicates with the pressurized air introduction portion 43b and the other end communicates with the exhaust passage 30. The injector body 43f supplies the secondary air introduced from the pressurized air introduction portion 43b to the exhaust passage 30 through the secondary air passage 43fb without being mixed with fuel. The injection port of the secondary air passage 43fb is formed to surround the injection port of the fuel injection passage 43fa.

  The fuel introduced into the fuel injection passage 43fa of the injector main body 43f is controlled by the injected fuel control valve 43c. The pressurized air introduced into the fuel injection passage 43fa of the injector main body 43f is controlled by the pressurized air control valve 43d. The pressurized air introduced into the secondary air passage 43fb of the injector body 43f is controlled by the secondary air control valve 43e.

  The opening degrees of the injected fuel control valve 43c, the pressurized air control valve 43d, and the secondary air control valve 43e are individually controlled by a control signal (indicated by a dotted arrow in FIG. 2) from the filter regeneration ECU 44. The injected fuel control valve 43c, for example, intermittently opens and closes the valve to intermittently introduce fuel into the fuel injection passage 43fa. Further, the pressurized air control valve 43d opens the valve at the timing when the injected fuel control valve 43c opens the valve, for example, and introduces pressurized air into the fuel injection passage 43fa. The secondary air control valve 43e adjusts the opening of the valve so that a predetermined supply amount is obtained, for example, and supplies a predetermined amount of pressurized air from the injector body 43f (secondary air passage 43fb) to the exhaust passage 30. To supply.

  The exhaust pipe injector 43 according to the present embodiment atomizes the fuel by using the shearing force of the pressurized air by injecting the fuel together with the pressurized air as described above. The exhaust pipe injector 43 reduces the particle size of the fuel, thereby improving the contact between the oxidation catalyst 41 and the fuel and promoting the oxidation reaction of the fuel. As a result, the fuel injected by the exhaust pipe injector 43 is converted into heat without slipping from the oxidation catalyst 41. In other words, the amount of heat generated by the fuel in the oxidation catalyst 41 can be controlled with high accuracy. Note that the secondary air supplied from the pressurized air introduction portion 43 b further diffuses the fuel injected from the fuel injection passage 43 fa in the exhaust passage 30.

  Further, the exhaust pipe injector 43 according to the present embodiment can control the oxygen amount in the exhaust gas with high accuracy by the supply amount of the secondary air supplied from the pressurized air introducing portion 43b.

  As described above, the exhaust pipe injector 43 according to the present embodiment can realize fine adjustment of the temperature and oxygen concentration of the exhaust gas reaching the PM filter 42.

  The filter regeneration ECU 44 (corresponding to the “control device” of the present invention) is an electronic control unit that performs regeneration control of the PM filter 42, and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), an input port, an output port, and the like. Then, the filter regeneration ECU 44 communicates with each part of the vehicle A such as a vehicle ECU (not shown), the exhaust pipe injector 43, and various sensors 51 to 53, and controls these, or data (detection signal) therefrom. Is received (dotted line in FIG. 1).

  Detection signals from various sensors 51 to 53 for detecting the state of the PM filter 42 and the state of the exhaust gas are input to the filter regeneration ECU 44. In the present embodiment, a temperature sensor 51 that detects the temperature of the exhaust gas, a flow sensor 52 that detects the flow rate of the exhaust gas, a PM sensor 53 that detects the PM accumulation amount of the PM filter 42, and the like are provided as various sensors. .

  The filter regeneration ECU 44 includes a filter regeneration time determination unit 44a and an exhaust pipe injector control unit 44b.

  The filter regeneration time determination unit 44a monitors the PM accumulation amount captured by the PM filter 42, and determines the regeneration time based on this. Note that the filter regeneration timing determination unit 44a determines the PM based on, for example, the detection signal of the PM sensor 53 disposed on the upstream side of the PM filter 42, the travel distance since the previous regeneration of the PM filter 42, and the like. The regeneration time of the filter 42 is determined.

  The exhaust pipe injector control unit 44b outputs control signals to the exhaust pipe injector 43 (injected fuel control valve 43c, pressurized air control valve 43d, and secondary air control valve 43e), and pressurizes from the exhaust pipe injector 43. Inject air and fuel. More specifically, the exhaust pipe injector control unit 44b allows the temperature of the PM filter 42 and the oxygen concentration in the exhaust gas reaching the PM filter 42 to be in a condition with good PM combustion efficiency when the PM filter 42 is regenerated. The amount of secondary air supplied from the exhaust pipe injector 43 is controlled.

  The filter regeneration timing determination unit 44a and the exhaust pipe injector control unit 44b are realized by the CPU referring to a control program and various data stored in the ROM, RAM, and the like, for example. However, the function is not limited to processing by software, and can of course be realized by a dedicated hardware circuit.

  In a recent internal combustion engine, a large amount of exhaust gas recirculation (EGR) may cause the oxygen concentration in the exhaust gas to decrease, and PM is efficiently burned when the PM filter 42 is regenerated. The problem of not doing has arisen. In particular, in the exhaust purification device 40 described above, since oxygen is used in the oxidation catalyst 41 disposed upstream of the PM filter 42, there is a problem that the oxygen concentration in the exhaust gas tends to be further lowered at the PM filter inlet. is there.

  Patent Document 1 described above is provided with a secondary air supply device for supplying secondary air upstream of the PM filter and the oxidation catalyst, and the secondary air is supplied from the secondary air supply device during regeneration of the PM filter. It also describes what to do. However, in the prior art of Patent Document 1, it is difficult to effectively increase the exhaust gas temperature or adjust the exhaust gas temperature and the oxygen amount in the PM filter. As a result, under restricted conditions such as a large amount of EGR, secondary air is excessively supplied, and the temperature of the exhaust gas may be significantly reduced.

  In this regard, according to the exhaust pipe injector 43 according to the present embodiment, such a problem can be solved and the regeneration of the PM filter 42 can be executed efficiently in a short time.

[Operation flow of exhaust pipe injector]
Next, the operation when the filter regeneration ECU 44 controls the exhaust pipe injector 43 will be described with reference to FIGS.

  FIG. 3 is a flowchart showing an example of the operation of the filter regeneration ECU 44. The flowchart shown in FIG. 3 is executed, for example, by the filter regeneration ECU 44 at a predetermined interval (for example, every second) according to a computer program.

  The filter regeneration ECU 44 (filter regeneration time determination unit 44a) first determines whether it is the regeneration time of the PM filter 42 based on the PM accumulation amount of the PM filter 42 (step S1). When the filter regeneration ECU 44 determines that it is not the regeneration time of the PM filter 42 (step S1: NO), the series of flow ends.

  On the other hand, if the filter regeneration ECU 44 (exhaust pipe injector control unit 44b) determines that it is time to regenerate the PM filter 42 (step S1: YES), the injection fuel control valve 43c and the pressurized air control valve of the exhaust pipe injector 43 are used. A control signal is output to 43d, and fuel and pressurized air are mixed and injected from the injector body 43f into the exhaust passage 30 (step S2).

  Next, the filter regeneration ECU 44 (exhaust pipe injector control unit 44b) determines whether or not to supply the secondary air based on the detection signals from the various sensors 51 to 53 (step S3). For example, the filter regeneration ECU 44 determines whether or not to supply the secondary air depending on whether or not the oxygen concentration in the exhaust gas is equal to or higher than a threshold (for example, 8% or higher) (step S3). When the filter regeneration ECU 44 (exhaust pipe injector control unit 44b) determines that the secondary air supply needs to be executed (step S3: YES), the filter regeneration ECU 44 (exhaust pipe injector control unit 44b) calculates the secondary air supply amount (step S4). The opening degree of the secondary air control valve 43e of the exhaust pipe injector 43 is controlled so as to be the supply amount (step S5).

  The filter regeneration ECU 44 proceeds to the subsequent determination process of step S6 after step S5 and when it is determined in step S3 that the secondary air supply need not be executed (step S3: NO).

  The filter regeneration ECU 44 determines whether or not the regeneration process of the PM filter 42 is completed based on the detection signal or the like of the PM sensor 53 (step S6), and steps S3 to S5 until the regeneration process of the PM filter 42 is completed. The process is repeatedly executed (step S6: NO). Then, when the regeneration process of the PM filter 42 is completed (step S6: YES), the filter regeneration ECU 44 outputs a control signal to the exhaust pipe injector 43 to inject fuel from the exhaust pipe injector 43, and the like. Is terminated (step S7), and a series of flows is terminated.

  Here, with reference to FIG. 4 and FIG. 5, an example of a calculation process when the filter regeneration ECU 44 determines the supply amount of secondary air in step S4 will be described.

  FIG. 4 is a diagram illustrating an example of the relationship between the oxygen concentration [%] in the exhaust gas in the PM filter 42 and the PM combustion rate (oxygen concentration characteristic of the PM combustion rate). FIG. 5 is a diagram showing an example of the relationship between the temperature [° C.] of the PM filter 42 and the PM combustion rate in the PM filter 42 (temperature characteristics of the PM combustion rate).

  4 and 5, the vertical axis indicates the PM combustion amount per unit time, and the horizontal axis indicates time. FIG. 4 shows experimentally obtained temporal changes in the PM combustion amount per unit time when the oxygen concentration [%] in the exhaust gas is changed under the condition where the temperature [° C.] of the exhaust gas is constant. Is. FIG. 5 shows an experiment of the temporal change of the PM combustion amount per unit time when the temperature [° C.] of the PM filter 42 is changed under the condition that the oxygen concentration [%] in the exhaust gas is constant. Is obtained by

  As apparent from FIG. 5, the temperature characteristic of the PM combustion rate includes a threshold temperature b1 (for example, 500 degrees to 600 degrees) at which the PM combustion speed rapidly decreases. On the other hand, as is apparent from FIG. 4, in the oxygen concentration characteristic of the PM combustion rate, the PM combustion rate that deteriorates as the oxygen concentration in the exhaust gas decreases is relatively slow compared to FIG. It is.

  Therefore, when supplying secondary air, it is desirable to prevent the temperature of the PM filter 42 from dropping below the threshold temperature b1. In the present embodiment, from the viewpoint, when supplying the secondary air, the supply amount of the secondary air is determined so that the exhaust gas reaching the oxidation catalyst 41 has a predetermined temperature or higher. Thereby, it is possible to reliably prevent the PM combustion rate from decreasing in the PM filter 42.

  Here, the temperature of the exhaust gas that reaches the PM filter 42 can be estimated from, for example, the temperature of the exhaust gas that reaches the oxidation catalyst 41 and the amount of heat generated by the fuel in the oxidation catalyst 41 or the like. And the calorific value which a fuel generate | occur | produces in the oxidation catalyst 41 grade | etc., Can be estimated or adjusted with the exhaust pipe injector 43 which concerns on this embodiment. In other words, the filter regeneration ECU 44 controls the temperature of the exhaust gas reaching the PM filter 42 with high accuracy by determining the supply amount of the secondary air so as to adjust the temperature of the exhaust gas reaching the oxidation catalyst 41. Is possible.

Thus, in step S4, the filter regeneration ECU 44 controls the temperature of the exhaust gas reaching the oxidation catalyst 41, for example, the exhaust gas flowing through the exhaust passage 30 and the heat equation (1 ) To determine the supply amount of secondary air. Expression (2) is obtained by converting Expression (1).
m1 × T1 × c + L × Ta × c = (m1 + L) × Tc × c (1)
⇒ L = m1 (T1-Tc) / (Tc-Ta) (2)
(However, m1: exhaust gas flow rate [g / s], T1: exhaust gas temperature [° C], c: specific heat [J / g · ° C], Ta: temperature of secondary air [° C], L: supply of secondary air Amount [g / s], Tc: target temperature of exhaust gas reaching the oxidation catalyst 41 [° C.])

  In the above formula (1), the target temperature Tc (for example, about 250 ° C.) of the exhaust gas reaching the oxidation catalyst 41 is, for example, the target temperature of the PM filter 42 determined from the temperature characteristics of the PM combustion rate, etc. And the amount of heat generated by the fuel. Further, the exhaust gas flow rate m1 and the exhaust gas temperature T1 are obtained based on detection signals of the temperature sensor 51 and the flow sensor 52. However, these data may be detection values that are directly detected using a sensor, or may be detection values that are indirectly estimated by a calculation process.

  In the above formula (1), the supply amount L of the secondary air is the sum of the pressurized air supplied from the fuel injection passage 43fa of the exhaust pipe injector 43 and the pressurized air supplied from the secondary air passage 43fb. It becomes. Accordingly, it is desirable that the filter regeneration ECU 44 controls the opening degree of the secondary air control valve 43e in consideration of the supply amount of the pressurized air supplied from the fuel injection passage 43fa.

  In the above formula (1), the target temperature Tc of the exhaust gas reaching the oxidation catalyst 41 is more preferably changed according to the amount of hydrocarbons injected from the exhaust pipe injector 43. In this case, of course, the amount of hydrocarbons injected from the exhaust pipe injector 43 may be adjusted as appropriate.

  As described above, according to the exhaust emission control device 40 according to the present embodiment, when the PM filter 42 is regenerated, the exhaust air injector 43 is used to pressurize the compressed air against the oxidation catalyst 42 disposed upstream of the PM filter 41. To supply fuel in a state of being atomized and diffused. Therefore, the exhaust purification device 40 according to the present embodiment promotes a rise in the temperature of the exhaust gas that reaches the PM filter 42 and can also finely adjust the temperature.

  Further, the exhaust purification device 40 according to the present embodiment has a configuration in which pressurized air is supplied as secondary air to the exhaust passage 30 using the exhaust pipe injector 43 when the PM filter 42 is regenerated. Therefore, the exhaust emission control device 40 according to the present embodiment can increase the oxygen concentration of the exhaust gas reaching the PM filter 42 and finely adjust the oxygen concentration.

  Further, when supplying the secondary air using the exhaust pipe injector 43, the exhaust purification device 40 according to the present embodiment is adapted to the temperature of the exhaust gas flowing through the exhaust passage 30 and the hydrocarbons injected from the exhaust pipe injector 43. Based on the amount, the supply amount is controlled so that the temperature of the exhaust gas reaching the oxidation catalyst 41 is equal to or higher than a predetermined temperature (for example, 250 ° C.). Therefore, it is possible to reliably prevent the secondary air from lowering the temperature of the PM filter 42 and reducing the PM combustion rate.

  Thus, the exhaust emission control device 40 according to the present embodiment is such that the PM combustion efficiency becomes as good as possible even under conditions where the oxygen concentration in the exhaust gas is reduced due to the large amount of EGR. In addition, the temperature and oxygen concentration of the exhaust gas can be controlled. As a result, the regeneration of the PM filter 42 can be executed efficiently in a short time.

(Other embodiments)
The present invention is not limited to the above embodiment, and various modifications can be considered.

  In the above embodiment, as an example of the exhaust pipe injector 43, the aspect having the fuel injection passage 43fa and the secondary air passage 43fb is shown. However, the configuration of the injector body 43f can be variously modified. For example, the secondary air passage 43fb is not provided, and the amount of pressurized air introduced into the fuel injection passage 43fa may be controlled.

  Moreover, although the aspect which has the external EGR apparatus 31 was shown as an example of the vehicle A in the said embodiment, of course, it can apply also to the vehicle which does not have the external EGR apparatus 31.

  Moreover, in the said embodiment, the aspect which calculates supply_amount | feed_rate of secondary air using Formula (1) was shown as an example of the exhaust pipe injector control part 44b of filter regeneration ECU44. However, the calculation process is not limited to the above, and can be variously modified. For example, the supply amount of secondary air may be calculated using the target temperature of the PM filter 42 instead of the target temperature of the exhaust gas reaching the oxidation catalyst 41.

  In the above embodiment, as an example of the configuration of the filter regeneration ECU 44, the functions of the filter regeneration time determination unit 44a and the exhaust pipe injector control unit 44b are described as being realized by a single computer. Of course, it may be done. For example, the function of the exhaust pipe injector control unit 44b may be realized by a plurality of computers. On the other hand, it is needless to say that the functions of the filter regeneration ECU 44 and the vehicle ECU may be realized by one ECU.

  In the above embodiment, as an example of the configuration of the filter regeneration ECU 44, the processes of the filter regeneration time determination unit 44a and the exhaust pipe injector control unit 44b are shown as being executed in a series of flows. May be executed in parallel.

  Moreover, in the said embodiment, the temperature sensor 51, the flow sensor 52, and PM sensor 53 were shown as an example of various sensors 51-53. However, it goes without saying that a temperature sensor or the like for detecting the exhaust gas temperature at the inlet of the PM filter 42 may be provided in addition to the above. On the other hand, the detection value of the detection target of the above sensor may be obtained indirectly by arithmetic processing using the detection value of another sensor, and in that case, a part of the above sensor may be omitted.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The present disclosure can be suitably used as an exhaust emission control device for an internal combustion engine that enables regeneration of the PM filter more efficiently.

DESCRIPTION OF SYMBOLS 10 Engine main body 20 Intake passage 21 Air cleaner 22 Turbocharger 23 Intake throttle valve 30 Exhaust passage 31 External EGR device 40 Exhaust purification device 41 Oxidation catalyst 42 PM filter 43 Exhaust pipe injector 44 Filter regeneration ECU
51 Temperature sensor 52 Flow rate sensor 53 PM sensor

Claims (5)

An oxidation catalyst and a particulate filter disposed in order from the upstream side to the downstream side in the exhaust passage of the internal combustion engine;
An exhaust pipe injector for supplying fuel together with pressurized air in the exhaust passage upstream of the oxidation catalyst;
An exhaust purification device for an internal combustion engine. A control device for controlling a supply amount of the pressurized air supplied from the exhaust pipe injector to the exhaust passage;
The exhaust emission control device for an internal combustion engine according to claim 1. The exhaust pipe injector includes a fuel injection passage that mixes the fuel with the pressurized air and supplies the fuel to the exhaust passage, and a secondary air passage that supplies the pressurized air to the exhaust passage without mixing with the fuel. And having
The control device controls a supply amount of the pressurized air supplied to the exhaust passage by adjusting an introduction amount of the pressurized air introduced into the secondary air passage;
The exhaust emission control device for an internal combustion engine according to claim 2. The control device, when regenerating the particulate filter,
Determining the supply amount of the pressurized air based on the temperature of the exhaust gas flowing through the exhaust passage so that the temperature of the exhaust gas reaching the oxidation catalyst is equal to or higher than a predetermined temperature;
The exhaust emission control device for an internal combustion engine according to claim 2 or 3. The control device, when regenerating the particulate filter,
When determining the supply amount of the pressurized air, further refer to the amount of hydrocarbons injected from the exhaust pipe injector,
The exhaust emission control device for an internal combustion engine according to claim 4.