JP2018080705A - 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 capable of reducing deterioration of fuel economy due to clogging preventive injection and improving reliability by suppressing changes over time of addition fuel injection amount.SOLUTION: A device includes: an exhaust emission control unit 44; a regeneration fuel addition valve 61 for the unit; an introduction passage 62a for introducing addition fuel into an exhaust pipe 42; and an ECU 100 for controlling the addition fuel injection amount. The device further includes: a compression mechanism 70 for taking in and compressing air and discharging the compressed air into the introduction passage 62a; and an air amount control unit 75 for adjusting the amount of the air. The unit 75 determines whether a temperature of the introduction passage 62a reaches a predetermined high temperature during regeneration processing of the exhaust emission control unit 44 and whether a regenerable temperature is reached. When the temperature reaches the predetermined high temperature, the compressed air is supplied into the introduction passage 62a. When the predetermined high temperature and the regenerable temperature are reached, the ECU 100 opens the addition valve 61 for a predetermined injection period that is approximately synchronized with and shorter than a supply period of the air.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas purification device for an internal combustion engine, and more particularly to an exhaust gas purification device for an internal combustion engine that injects added fuel into an exhaust pipe for regeneration of an exhaust gas purification unit.

  In an exhaust gas purification apparatus for an internal combustion engine mounted on a vehicle such as an automobile, regeneration of the catalyst for exhaust gas purification is performed by using the addition of fuel to the exhaust gas and the resulting increase in exhaust temperature, or diesel In many cases, regeneration processing of a particulate filter (hereinafter referred to as DPF) is executed.

  In such an exhaust gas purification apparatus for an internal combustion engine, the fuel adheres to an addition valve for adding fuel to the exhaust gas, a high temperature wall surface forming an introduction passage (injection hole) for the added fuel into the exhaust pipe, and the deposit is generated. When deposited, the spray characteristics change over time due to a change in the injection amount of the added fuel.

  Accordingly, in order to suppress such a change with time in the injection amount and spray characteristics of the added fuel, there is a type that performs the clogging prevention addition in which the added fuel is injected at a predetermined time interval to cool the wall of the addition valve and the introduction passage. (For example, refer to Patent Document 1).

JP 2005-106047 A

  However, in the conventional exhaust gas purification apparatus for an internal combustion engine as described above, there is room for improvement in fuel consumption because the fuel consumption is reduced due to the necessity of executing the added fuel injection for preventing clogging.

  Therefore, the present invention provides an exhaust emission control device for an internal combustion engine that can achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of changes over time in the added fuel injection amount and spray characteristics. Objective.

  In order to achieve the above object, an exhaust gas purification apparatus for an internal combustion engine according to the present invention includes an exhaust gas purification unit that is attached to an exhaust pipe of an internal combustion engine and purifies exhaust gas that passes through the exhaust pipe, and a fuel that regenerates the exhaust gas purification unit. An addition valve for injecting and adding to the exhaust gas, an introduction passage forming member for forming an introduction passage for introducing fuel from the addition valve into the exhaust pipe, and the addition valve according to operating conditions of the internal combustion engine An internal combustion engine exhaust purification device comprising an addition control unit for controlling the amount of fuel injected from the compressor, and compressing the air by taking it in from the outside of the exhaust pipe and supplying it into the introduction passage; An air amount control unit that adjusts the amount of air supplied from the compression mechanism into the introduction passage according to operating conditions of the internal combustion engine, and the air amount control unit includes the introduction passage It is determined whether or not a predetermined high temperature has been reached and whether or not the exhaust purification unit has reached a regenerative temperature, and when the predetermined high temperature has been reached, the air pressurized by the compression mechanism is The addition control unit is substantially synchronized with the supply period of the air under the condition of reaching the predetermined high temperature and being at the regenerative temperature, and supplying into the introduction passage which is a communication passage into the exhaust pipe; The fuel is injected into the exhaust gas from the introduction passage by opening the addition valve during a predetermined injection period shorter than the period.

  With this configuration, the air taken in from the outside is discharged into the introduction passage, the introduction passage formation member and the addition valve are cooled, the adhering fuel is eliminated, and further, deposited as a deposit on the opening side of the introduction passage into the exhaust pipe. This makes it possible to blow off deposits that are easily generated into the exhaust pipe. In addition, the amount of air supplied from the compression mechanism into the introduction passage is adjusted according to the operating conditions of the internal combustion engine, so that the adhering fuel that easily deposits deposits is effectively eliminated, and into the exhaust pipe of the introduction passage. The deposit accumulation in the opening portion or the like is effectively suppressed. As a result, it is possible to sufficiently suppress or eliminate the frequency of added fuel injection to prevent clogging while effectively suppressing the change in the added fuel injection amount over time and improving the reliability of the exhaust emission control device. Can be improved.

  In the exhaust gas purification apparatus for an internal combustion engine of the present invention, in addition to cooling the addition valve and the introduction passage by discharging the air taken from outside into the introduction passage, the addition valve and the introduction passage are made of engine cooling water. You may make it cool. Also, the timing of discharging and supplying compressed air from the compression mechanism into the introduction passage may be synchronized with the timing of fuel injection by the addition valve. By doing so, the fuel adhering in the introduction passage can be effectively blown off by the compressed air before gumming or depositing.

  In the exhaust gas purification apparatus for an internal combustion engine of the present invention, the internal combustion engine further compresses the intake air of the internal combustion engine using exhaust energy and supercharges the air to the internal combustion engine, and An intake pressure sensor for detecting the pressure of air in the intake pipe of the internal combustion engine, and the air amount control unit is supplied from the compression mechanism into the introduction passage using a detection value of the intake pressure sensor. The air pressure may be controlled.

  According to the present invention, it is possible to provide an exhaust emission control device for an internal combustion engine that can achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of temporal change in added fuel injection amount and spray characteristics. it can.

1 is a schematic configuration diagram of an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention. FIG. 3 is a partially enlarged view of an addition valve and an introduction passage in the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention. It is a flowchart which shows the process sequence of the air supply routine to the introduction channel | path in the exhaust gas purification apparatus of the internal combustion engine which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of the exhaust gas purification device of the internal combustion engine which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the exhaust gas purification device of the internal combustion engine which concerns on the 3rd Embodiment of this invention. It is a timing chart which shows the relationship between the addition fuel injection timing in the exhaust gas purification apparatus of the internal combustion engine which concerns on the 3rd Embodiment of this invention, and the opening timing of an air supply solenoid valve.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention.

  First, the configuration will be described.

  FIG. 1 to FIG. 3 show a first embodiment of an exhaust gas purification apparatus for an internal combustion engine according to the present invention, which is an in-line four-cylinder diesel engine that is a multi-cylinder internal combustion engine. 10 (hereinafter simply referred to as the engine 10).

  As shown in FIG. 1, the engine 10 has a plurality of cylinders 11 (only one is shown in FIG. 1). A piston 12 is housed in each cylinder 11 and a combustion chamber 13 is formed. ing. The piston 12 is connected to a crankshaft 15 via a connecting rod 14, and each combustion chamber 13 is provided with an intake valve 16 and an exhaust valve 17. Further, the engine 10 includes a common rail fuel injection device 20 that injects fuel into the combustion chamber 13, an intake device 30 that sucks air into the combustion chamber, and an exhaust device 40 that exhausts exhaust gas from the combustion chamber 13. And are equipped.

  Further, the engine 10 includes a turbocharger 50 that compresses intake air in the intake device 30 by using exhaust energy in the exhaust device 40 and supercharges air into the combustion chamber, and intakes a part of the exhaust gas. It is equipped with an EGR device (not shown) that recirculates to the side and recirculates.

  The fuel injection device 20 includes a supply pump 21 (not shown) that pressurizes and supplies fuel, a common rail 22 that introduces and accumulates fuel from the supply pump 21, and a corresponding cylinder 11 that supplies fuel supplied through the common rail 22. And a plurality of fuel injection valves 23 for injecting fuel.

  The supply pump 21 is driven using, for example, the rotational power of the engine 10, and the common rail 22 distributes and supplies the high-pressure fuel supplied from the supply pump 21 to the plurality of fuel injection valves 23 while accumulating and storing the high-pressure fuel. It has become. Each fuel injection valve 23 is composed of a known electromagnetically driven needle valve, and is driven to open by an injection command signal from an electronic control unit 100 (control device; hereinafter referred to as ECU 100) described later. .

  The intake device 30 includes an intake pipe 32 having a surge tank 31 and an intake manifold (not shown) on the downstream side, a throttle valve 33 for adjusting the intake amount into the engine 10 in the vicinity of the upstream end of the surge tank 31, An air cleaner 34 that cleans the intake air with a filter upstream of the pipe 32 and an intake pressure sensor 35 that detects the pressure of the air in the intake pipe 32 are mounted. The intake device 30 is further provided with an intercooler (not shown) that cools the air heated while being supercharged by the turbocharger 50 on the upstream side of the intake pressure sensor 35.

  The exhaust device 40 has an exhaust pipe 42 having an exhaust manifold (not shown) on the upstream side, a known exhaust purification unit 44 attached to the exhaust pipe 42 on the downstream side of the turbocharger 50, and the temperature of the exhaust purification unit 44. And a catalyst temperature sensor 46 to be detected.

  The exhaust purification unit 44 is a known unit that performs exhaust purification on nitrogen oxides (NOx) and fine particles (particulates) in the exhaust gas discharged from the combustion chamber 13 and passing through the exhaust pipe 42.

  The exhaust purification unit 44 supports a NOx occlusion / reduction type catalyst including a noble metal catalyst and a NOx occlusion material on a porous ceramic substrate of DPF, for example, so that the air-fuel ratio of the exhaust gas introduced into the interior is lean (oxidation). NOx (NO2 or NO) is occluded during normal operation in an atmosphere), while the NOx occlusion material occludes when the air-fuel ratio of the exhaust gas introduced inside becomes the stoichiometric air-fuel ratio or more rich (reducing atmosphere). NOx that has been reduced is reduced to N2, CO2 and H2O by HC and CO in the exhaust gas. In this case, PM can be continuously oxidized by active oxygen in the atmosphere and oxygen in the gas phase. It goes without saying that the exhaust purification system of the exhaust purification unit 44 is not limited to the system exemplified here.

  The turbocharger 50 includes a compressor wheel 51 and an exhaust turbine 52 that are integrally connected to each other in the rotational direction. The exhaust turbine 52 is rotated by the exhaust energy of the engine 10 to rotate the compressor wheel 51, and the intake air Is compressed so that positive pressure air can be supercharged into the engine 10.

  The exhaust device 40 is provided with an addition valve 61 for adding and supplying fuel to the exhaust gas downstream from the turbocharger 50 and upstream from the exhaust purification unit 44, and fuel from the addition valve 61. A tubular introduction passage forming member 62 that forms an introduction passage 62a for introducing the gas into the exhaust pipe 42 is mounted.

  The addition valve 61 performs the regeneration process of the catalyst in the exhaust purification unit 44, for example, the above-described NOx occlusion / reduction type catalyst reduction process, by using the fuel addition to the exhaust gas and the exhaust gas temperature rise caused thereby. A DPF regeneration process is executed.

  As shown in FIG. 2, the introduction passage 62 a for introducing added fuel formed by the introduction passage forming member 62 is located downstream of the turbocharger 50 and upstream of the exhaust purification unit 44. It opens on the inner wall surface 42 b and communicates with the exhaust passage 42 a in the exhaust pipe 42.

  The addition valve 61 is fastened and supported by the introduction passage forming member 62 so that the nozzle portion 61b on the tip side having the injection hole 61a is exposed in the introduction passage 62a.

  The addition valve 61 operates the electromagnetic actuator 61t on the rear end side in accordance with a fuel addition command signal from the ECU 100, and opens the valve body 61v at a timing and opening degree (duty ratio) according to the fuel addition command signal. By driving the valve, the valve seat 61s is displaced in the axial direction.

  The ECU 100 functions as an addition control unit that controls the amount of fuel injected from the addition valve 61 in accordance with the operating conditions of the engine 10.

  On the other hand, air is taken in from the outside of the exhaust pipe 42 between the intake pipe 32 upstream of the compressor wheel 51 of the turbocharger 50 and the exhaust pipe 42 downstream of the exhaust turbine 52 of the turbocharger 50. And a compression mechanism 70 for discharging the compressed air as compressed air into the introduction passage 62a.

  The compression mechanism 70 includes an air introduction pipe 71, an air compression pump 72, a flow rate adjustment valve 73, and an introduction passage temperature sensor 74, and the air introduction pipe 71 is upstream of the compressor wheel 51. And the introduction passage forming member 62 so that air can be supplied from the intake passage 32a of the intake pipe 32 to the introduction passage 62a.

  The air compression pump 72 is an electric or mechanical pump mounted in the middle of the air introduction pipe 71. The air compression pump 72 takes in the air in the intake passage 32a, compresses it, and discharges it as compressed air into the introduction passage 62a. It can be done.

  The flow rate adjustment valve 73 is controlled in opening by the ECU 100, and together with the ECU 100, air that adjusts the amount of air supplied from the compression mechanism 70 into the introduction passage 62 a according to at least the operating conditions of the engine 10. A quantity control unit 75 is configured.

  The introduction passage temperature sensor 74 detects the temperature of the introduction passage 62a of the added fuel from the addition valve 61 into the exhaust pipe 42, particularly the temperature near the wall surface in the vicinity of the opening on the inner wall surface 42b. The detected temperature of the introduction passage temperature sensor 74 is taken into the ECU 100.

  The ECU 100 as the air amount control unit 75 further selects one of the temperature of the exhaust purification unit 44, the intake air amount of the engine 10, the cooling water temperature, the fuel injection amount, and other operating conditions according to the temperature detected by the introduction passage temperature sensor 74. Accordingly, the opening degree of the flow rate adjustment valve 73 is variably controlled.

  Specifically, the ECU 100 detects a temperature at which the temperature of the introduction passage 62a detected by the introduction passage temperature sensor 74 facilitates gumming due to oxidation of the attached fuel and other deposits Fs and deposits easily, for example, 160 degrees Celsius. It is determined whether or not the degree is reached. If the result of the determination is affirmative that it is 160 degrees Celsius or more, the flow rate adjusting valve 73 is opened, and the fuel adhering to the introduction passage 62a is compressed before being gummed or deposited. The air is blown into the exhaust pipe 42 by air. Here, the amount of air supplied from the compression mechanism 70 into the introduction passage 62a of the added fuel is increased as the temperature of the introduction passage 62a is higher.

  Further, the ECU 100 substantially synchronizes the discharge / supply timing of the compressed air from the compression mechanism 70 into the introduction passage 62a of the added fuel with the timing at which fuel is injected into the exhaust pipe 42 from the addition valve 61 through the introduction passage 62a. By doing so, the fuel adhering in the introduction passage 62a is blown off quickly and effectively.

Although the specific hardware configuration of the ECU 100 is not shown, the ECU 100 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a backup memory, and further includes an A / D converter. And an input interface circuit including a buffer and an output interface circuit including a drive circuit for actuators.

  The input interface circuit of the ECU 100 is connected to the intake pressure sensor 35, the catalyst temperature sensor 46, and the introduction passage temperature sensor 74 described above, and is connected to a known engine speed sensor 81 and a water temperature sensor 83, and is not shown. An accelerator opening sensor, an air flow meter, an exhaust air-fuel ratio sensor, a fuel pressure sensor, and the like are connected.

  The output interface circuit of the ECU 100 is connected to actuators such as a fuel injection valve 23, a throttle motor 33a that operates the throttle valve 33, an addition valve 61, an air compression pump 72, a flow rate adjustment valve 73, and an EGR valve.

  Further, in the ROM and backup memory of the ECU 100, fuel injection control for controlling fuel injection by the fuel injection valve 23 and the addition valve 61, regeneration control for the exhaust purification unit 44, introduction of the addition valve 61 and added fuel by the compression mechanism 70, and the like. Various control programs for executing cooling control and the like of the passage 62a are stored, and setting values and determination conditions necessary for the control are stored.

  Then, the ECU 100 executes the control program stored in advance in the ROM, so that the next processing related to the regeneration processing of the exhaust purification unit 44 is performed based on various sensor information and setting information stored in the backup memory. It is designed to demonstrate multiple functions.

  That is, the ECU 100 calculates, for example, a function for determining whether or not the required timing for the regeneration process is reached every predetermined time, or calculates the fuel addition execution timing and the injection amount by the addition valve 61 when the regeneration process is required, A function of outputting a fuel addition command signal corresponding to the calculation result to the addition valve 61 and executing a regeneration process is exhibited.

  In this embodiment, in addition to cooling the wall surface of the addition valve 61 and the introduction passage 62a by discharging the air taken from the outside of the exhaust pipe 42 into the introduction passage 62a of the addition fuel, the addition valve 61 and The wall surface of the introduction passage 62a may be cooled by engine cooling water. That is, a cooling water passage and piping for cooling the wall surfaces of the addition valve 61 and the introduction passage 62a may be provided. The temperature of the introduction passage 62a is not limited to the value detected by the introduction passage temperature sensor 74. The engine speed detected by the engine speed sensor 81, the fuel injection amount calculated by the ECU 100, the water temperature You may estimate and calculate based on the cooling water temperature etc. which were detected by the sensor 83. FIG.

  Next, a control program related to the regeneration process executed by the ECU 100 will be described.

  FIG. 3 shows a flow of an air supply routine that is executed every predetermined time during the operation after the warm-up of the engine 10 is completed.

  As shown in FIG. 3, when this air supply routine is started, first, the temperature of the introduction passage 62a detected by the introduction passage temperature sensor 74 is taken in (step 301).

  Next, it is determined whether or not the temperature of the introduction passage 62a detected by the introduction passage temperature sensor 74 is 160 degrees Celsius (predetermined high temperature) or more (step 302).

  At this time, if the temperature of the introduction passage 62a is less than 160 degrees Celsius (NO in step 302), the process returns to step 301 and the temperature of the introduction passage 62a is taken in again.

  On the other hand, if the temperature of the introduction passage 62a is 160 degrees Celsius or higher (YES in Step 302), it is then determined whether or not the added fuel is being injected for regeneration of the exhaust purification unit 44 (Step 303). .

  At this time, if the added fuel injection for regeneration of the exhaust purification unit 44 is being performed (YES in step 303), it is then determined whether or not the exhaust purification unit 44 is at or above the renewable temperature (step 304). If the exhaust purification unit 44 is equal to or higher than the reproducible temperature (YES in step 304), the flow rate adjustment valve 73 of the compression mechanism 70 is controlled to the valve opening side, and compressed air is supplied into the added fuel introduction passage 62a ( Step 305).

  On the other hand, when the added fuel injection for regeneration of the exhaust purification unit 44 is not being performed (NO in step 303), the flow rate adjustment of the compression mechanism 70 is performed without determining whether or not the exhaust purification unit 44 is at or above the renewable temperature. The valve 73 is controlled to the valve opening side, and compressed air is supplied into the added fuel introduction passage 62a (step 305).

  Next, the operation will be described.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment configured as described above, an additional fuel introduction passage into the exhaust passage 42a in a state in which fresh air taken from the outside of the exhaust passage 42a is compressed. The introduction passage forming member 62 and the addition valve 61 are cooled and discharged to the inside of 62a, and the fuel adhering to the inner wall surface of the addition valve 61 and the introduction passage 62a is removed to the exhaust passage 42a side.

  In particular, the deposit Fs such as deposited fuel that easily deposits as a deposit on the opening side of the introduction passage 62a into the exhaust pipe 42 can be blown into the exhaust pipe 42.

  As a result, it is possible to improve the reliability of the exhaust emission control device by effectively suppressing the time-dependent changes in the added fuel injection amount and the spray characteristics from the addition valve 61 into the exhaust pipe 42, and the addition valve 61 is clogged. Since the frequency of the added fuel injection for prevention can be sufficiently suppressed or eliminated, the fuel consumption of the engine 10 can be improved.

  Further, in the present embodiment, during the regeneration process of the exhaust purification unit 44, the timing of discharge / supply of compressed air from the compression mechanism 70 into the introduction passage 62a is the injection of the added fuel into the introduction passage 62a by the addition valve 61. Since it is substantially synchronized with the timing, the fuel adhering in the introduction passage 62a can be effectively blown off by the compressed air before being gummed or deposited.

  As a result, even if the additive fuel injection for preventing clogging is not executed, the time-dependent changes in the additive fuel injection amount and the spray characteristics due to deposit accumulation are effectively suppressed, and the fuel consumption and reliability of the engine 10 can be improved. it can.

  As described above, according to the exhaust gas purification apparatus for an internal combustion engine of the present embodiment, it is possible to achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of changes over time in the added fuel injection amount and spray characteristics. An exhaust gas purification device for an internal combustion engine that can be provided can be provided.

(Second Embodiment)
FIG. 4 shows a schematic configuration of an exhaust emission control device for an internal combustion engine according to the second embodiment of the present invention. Each embodiment described below has a configuration similar to that of the above-described first embodiment. Therefore, the same or similar components as those of the first embodiment are illustrated in FIG. The same reference numerals as those of the corresponding components in FIG. 3 are used, and differences from the first embodiment will be described below.

  In the present embodiment, the conditions for a large amount of fuel supply, that is, the conditions for the high temperature of the introduction passage 62a coincide with many engine operating areas in the turbocharging area of the turbocharger 50. By introducing the pressurized air downstream of the compressor wheel 51 into the introduction passage 62a through the communication pipe 76, the air compression pump 72 provided in the first embodiment is omitted in the compression mechanism 70. It is a thing.

  In this case, since the air pressure downstream of the compressor wheel 51 of the turbocharger 50 varies depending on the operating region of the engine 10, the ECU 100 uses the detected value of the intake pressure sensor 35 to set the opening of the flow rate adjustment valve 73. Calculate and control.

  Also in this embodiment, in the state where the fresh air taken in from the outside of the exhaust passage 42a is compressed by the compressor wheel 51 of the turbocharger 50, the inside of the introduction passage 62a of the added fuel into the exhaust passage 42a. As in the first embodiment, the internal combustion engine can achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of changes over time in the added fuel injection amount and spray characteristics. An exhaust emission control device for an engine can be provided.

  In addition, in the present embodiment, the dedicated air supply pump 72 for supplying air in the first embodiment can be omitted, and cost reduction and further reduction in fuel consumption can be achieved.

(Third embodiment)
5 and 6 show a schematic configuration of an exhaust emission control device for an internal combustion engine according to a third embodiment of the present invention.

  In the present embodiment, as shown in FIG. 5, by replacing the flow rate adjustment valve 73 of the compression mechanism 70 in the first embodiment with a highly responsive electromagnetic valve 77, as shown in FIG. (The center of the air supply period Tb in the figure) is synchronized with the injection timing of the added fuel from the addition valve 61 (the center of the added fuel injection period Ta in the figure) with high accuracy. Further, the air supply period Tb by the compression mechanism 70 is longer than the added fuel injection period Ta by the addition valve 61.

  In this case, the supply timing and supply period Tb of the external air into the introduction passage 62a are calculated by the ECU 100 based on the detection signal of the crank angle sensor 85.

  Also in the present embodiment, the fresh air taken from the outside of the exhaust passage 42a is compressed by the compressor wheel 51 of the turbocharger 50, and then the inside of the introduction passage 62a for the added fuel into the exhaust passage 42a. As in the first embodiment, the internal combustion engine can achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of changes over time in the added fuel injection amount and spray characteristics. An exhaust emission control device for an engine can be provided.

  Moreover, in the present embodiment, the supply amount of external air into the introduction passage 62a can be minimized.

  In each of the embodiments described above, the compression mechanism 70 is configured to cool the addition valve 61 and the introduction passage forming member 62 by discharging the air taken in from the intake passage 32a into the introduction passage 62a. The addition valve 61 and the wall surface part of the introduction passage 62a may have a water jacket as a cooling part that can be cooled by engine cooling water.

  In addition, the present invention uses the addition of fuel to the exhaust gas and the resulting increase in the exhaust temperature to perform regeneration processing of the exhaust purification catalyst and DPF, or sulfur regeneration recovery processing and other regeneration processing. Needless to say, the internal combustion engine may be an internal combustion engine using another fuel instead of a diesel engine.

  As described above, the present invention provides an exhaust emission control device for an internal combustion engine that can achieve both a reduction in fuel consumption deterioration due to clogging prevention injection and an improvement in reliability due to suppression of temporal change in added fuel injection amount and spray characteristics. It can be provided. The present invention is useful for an exhaust gas purification apparatus for an internal combustion engine, particularly an exhaust gas purification apparatus for an internal combustion engine that injects added fuel into an exhaust pipe for regeneration of an exhaust gas purification unit.

DESCRIPTION OF SYMBOLS 10 ... Engine (multi-cylinder internal combustion engine), 11 ... Cylinder, 12 ... Piston, 13 ... Combustion chamber, 15 ... Crankshaft, 16 ... Intake valve, 17 ... Exhaust valve, 20 ... Fuel injection device, 21 ... Supply pump, 22 DESCRIPTION OF SYMBOLS ... Common rail, 23 ... Fuel injection valve, 30 ... Intake device, 32 ... Intake pipe, 32a ... Intake passage, 35 ... Intake pressure sensor, 40 ... Exhaust device, 42 ... Exhaust pipe, 42a ... Exhaust passage, 42b ... Inner wall surface, 44 ... exhaust purification unit, 46 ... catalyst temperature sensor, 50 ... turbocharger, 51 ... compressor wheel, 52 ... exhaust turbine, 61 ... addition valve, 61a ... injection hole, 61b ... nozzle part, 62 ... introduction passage forming member , 62a ... introduction passage, 70 ... compression mechanism, 71 ... air introduction pipe, 72 ... air compression pump, 73 ... flow rate adjusting valve, 74 ... introduction passage temperature sensor, 75 ... air amount control unit, 7 ... Communication pipe, 77 ... Solenoid valve, 81 ... Engine speed sensor, 83 ... Water temperature sensor, 85 ... Crank angle sensor, 100 ... ECU (electronic control unit, air amount control unit, addition control unit), Ta ... Addition fuel injection Period (predetermined injection period), Tb ... Air supply period

Claims (2)

An exhaust purification unit mounted on an exhaust pipe of an internal combustion engine and purifying exhaust gas passing through the exhaust pipe;
An addition valve for injecting fuel to regenerate the exhaust purification unit and adding it to the exhaust gas;
An introduction passage forming member for forming an introduction passage for introducing fuel from the addition valve into the exhaust pipe;
An exhaust gas purification apparatus for an internal combustion engine, comprising: an addition control unit that controls an injection amount of fuel from the addition valve in accordance with operating conditions of the internal combustion engine,
A compression mechanism that takes in air from the outside of the exhaust pipe, compresses the air, and supplies the compressed air into the introduction passage;
An air amount control unit that adjusts the amount of air supplied from the compression mechanism into the introduction passage according to operating conditions of the internal combustion engine;
Is provided,
The air amount control unit determines whether or not the introduction passage has reached a predetermined high temperature and whether or not the exhaust purification unit has reached a regenerative temperature. Supplying air pressurized by the compression mechanism into the introduction passage which is a communication passage into the exhaust pipe;
The addition control unit opens the addition valve during a predetermined injection period that is substantially synchronized with and shorter than the air supply period under the condition where the predetermined high temperature is reached and the regeneration temperature is reached. An exhaust gas purification apparatus for an internal combustion engine, characterized in that fuel is injected into the exhaust gas from the introduction passage by being valved. A turbocharger in which the internal combustion engine compresses intake air of the internal combustion engine by using exhaust energy and supercharges the air to the internal combustion engine; and an intake pressure to detect the pressure of air in the intake pipe of the internal combustion engine A sensor,
2. The exhaust of the internal combustion engine according to claim 1, wherein the air amount control unit controls a pressure of air supplied from the compression mechanism into the introduction passage using a detection value of the intake pressure sensor. Purification equipment.

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