JP4069043B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust fuel addition control device that controls fuel addition to exhaust gas by an addition valve disposed in an exhaust system.

  2. Description of the Related Art In recent years, exhaust gas purification apparatuses that collect and purify particulate matter (PM) in exhaust gas using a filter provided in an exhaust system have been adopted in internal combustion engines such as in-vehicle diesel engines. In such an exhaust purification device, before the filter is clogged due to the accumulated PM, it is necessary to regenerate the filter by removing the accumulated PM.

  Conventionally, the thing of patent document 1 is known as an exhaust gas purification apparatus which performs PM regeneration of such a filter. In this exhaust purification apparatus, a catalyst for promoting the oxidation of PM is carried on the filter, and an addition valve for adding fuel to the exhaust is provided on the exhaust upstream side of the exhaust system filter. Then, an unburned fuel component such as nitrogen carbide (HC) is supplied to the filter through fuel addition from the addition valve, and an oxidation reaction of the unburned fuel component is generated on the filter. I try to raise the temperature. Thus, the filter is regenerated by promoting the oxidation reaction of PM with the catalyst in a sufficiently active state.

  In addition, in an exhaust gas purification apparatus for an internal combustion engine equipped with such an addition valve, fuel is directly fed to a catalyst carried on a filter or the like through addition of fuel into the exhaust, so that the PM, nitrogen oxide (NOx), etc. In some cases, an unburned fuel component serving as a reducing agent necessary for purification of exhaust components is supplied.

Further, by performing sub-injection, so-called after injection, separately during the compression stroke or exhaust stroke after the main fuel injection for combustion is performed from the fuel injection valve disposed in each cylinder of the internal combustion engine, the catalyst An exhaust gas purification apparatus for an internal combustion engine that supplies unburned fuel components to the fuel is also known.
Japanese Patent Laid-Open No. 5-44434

  By the way, in an exhaust gas purification apparatus for an internal combustion engine that supplies unburned fuel components to the catalyst through addition of fuel to the exhaust by the addition valve and after-injection from the fuel injection valve, supply of such unburned fuel As a result, the unburned fuel component in the exhaust gas may become excessive. As a result, most of the unburned fuel components are not fully oxidized by the catalyst and are discharged in an incomplete combustion state, and a large amount of white smoke may be generated in the exhaust.

  The problem to be solved by the present invention is to provide an exhaust fuel addition control device capable of suitably suppressing the generation of such white smoke.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
(means)
According to the first aspect of the present invention, the supply amount of the unburned fuel component to the catalyst disposed in the exhaust system exceeds the amount discharged to the exhaust system of the internal combustion engine in accordance with the combustion related to the generation of the engine output. In an exhaust gas purification apparatus for an internal combustion engine that implements an increase control that increases the amount of white smoke, the acceleration state of high back pressure, that is, the amount of unburned fuel component in the exhaust, the flow rate and the flow rate of exhaust gas, A determination means for determining whether or not the internal combustion engine is in this acceleration state based on the amount of change in the engine rotational speed with respect to an acceleration state that increases to an extent that causes generation, and the determination means causes the internal combustion engine to enter the acceleration state. when it is certain effect determination, than when it is not, as its gist in that it comprises a reduction unit for performing a process for reducing the amount of increase in the supply amount of the unburned fuel component in the increasing control.

According to the second aspect of the present invention, the supply amount of the unburned fuel component to the catalyst disposed in the exhaust system exceeds the amount discharged to the exhaust system of the internal combustion engine in accordance with the combustion related to the generation of the engine output. In an exhaust gas purification apparatus for an internal combustion engine that implements an increase control that increases the amount of white smoke, the acceleration state of high back pressure, that is, the amount of unburned fuel component in the exhaust, the flow rate and the flow rate of exhaust gas, A determination means for determining whether or not the internal combustion engine is in this acceleration state based on the amount of change in the engine rotational speed with respect to an acceleration state that increases to an extent that causes generation, and the determination means causes the internal combustion engine to enter the acceleration state. when it is certain fact determined, and its gist in that it comprises a stop means for processing for stopping the increase control.

  According to a third aspect of the present invention, in the exhaust gas purification apparatus for an internal combustion engine according to the first or second aspect, the increase control is performed by adding fuel into the exhaust gas by an addition valve disposed in the exhaust system. The gist of this is

  According to a fourth aspect of the present invention, in the exhaust gas purification apparatus for an internal combustion engine according to the first or second aspect, the increase control is provided for the combustion by a fuel injection valve for injecting the fuel for the combustion. The gist of the present invention is that the sub-injection of fuel is performed separately from the fuel injection.

According to a fifth aspect of the present invention, in an exhaust gas purification apparatus for an internal combustion engine that is provided in an exhaust system of the internal combustion engine and includes an addition valve that adds fuel to the exhaust gas, an acceleration state of high back pressure, that is, an increase in back pressure is achieved. With respect to the acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such a level that white smoke is generated, whether the internal combustion engine is in this acceleration state or not is changed. A determination means for determining based on the amount, and a process for reducing the amount of fuel added from the addition valve when the determination means determines that the internal combustion engine is in the acceleration state, as compared to when it is not The gist of the present invention is to include a reducing means for performing the above.

According to a sixth aspect of the present invention, in an exhaust gas purification apparatus for an internal combustion engine that is provided in an exhaust system of the internal combustion engine and includes an addition valve that adds fuel to the exhaust gas, an acceleration state of high back pressure, that is, an increase in back pressure is achieved. With respect to the acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such a level that white smoke is generated, whether the internal combustion engine is in this acceleration state or not is changed. a determination unit based on the amount, when it is determined that the engine is in the accelerating state by the judging means, and its gist in that it comprises a stop means for processing for stopping the implementation of the fuel addition To do.
According to a seventh aspect of the present invention, in the exhaust gas purification apparatus for an internal combustion engine according to the first or fifth aspect, the reduction means is configured to perform exhaust when the determination means determines that the internal combustion engine is in the acceleration state. The gist of the present invention is to always execute the processing for reducing the amount of fuel supplied to the inside.
According to an eighth aspect of the present invention, in the exhaust gas purification apparatus for an internal combustion engine according to the second or sixth aspect, when the stop means determines that the internal combustion engine is in the acceleration state by the determination means, The gist is to always execute the process of stopping the fuel supply to the inside.

(Function and effect)
In an exhaust gas purification apparatus for an internal combustion engine having a catalyst disposed in an exhaust system, the catalyst bed temperature is increased through supply of unburned fuel components to the catalyst, or the unburned fuel components are supplied to the catalyst as a reducing agent. As a result, the purification reaction of exhaust components triggered by the catalyst may be promoted. The supply of the unburned fuel component to such a catalyst is performed by adding fuel into the exhaust by an addition valve arranged in the exhaust system, as described in claim 3 and claims 5 and 6. As described above, the fuel injection valve that injects the fuel to be used for combustion can perform the sub injection of the fuel different from the injection of the fuel to be used for the combustion.

  On the other hand, when the internal combustion engine is in an acceleration state, such as during no-load racing, the amount of fuel used for combustion is increased, and the air-fuel ratio of the mixture of fuel and air is made richer than usual. Unburned fuel components such as hydrocarbons discharged in response to combustion increase more than usual. That is, at the time of rapid acceleration of the internal combustion engine, many unburned fuel components are discharged to the exhaust system due to combustion related to the generation of engine output, and even if fuel addition or sub-injection is not performed in the exhaust, There are many unburned fuel components inside. Further, during such acceleration, the exhaust pressure from the combustion chamber increases and the back pressure increases. Therefore, if unburned fuel components are supplied by the above fuel addition or sub-injection at this time, the unburned fuel components in the exhaust gas will be excessive, and the exhaust gas flow rate / flow velocity will increase due to the increase in back pressure. This causes the unburned fuel component to be discharged without being sufficiently oxidized, which may cause a large amount of white smoke.

  In this regard, in the configuration according to claim 1, when the internal combustion engine is in an acceleration state, the increase amount of the supply amount of the unburned fuel component in the increase control performed to increase the supply amount of the unburned fuel component to the catalyst. Is reduced more than usual. According to the fifth aspect of the present invention, during the rapid acceleration of the internal combustion engine, the amount of fuel added to the exhaust by the addition valve is reduced more than usual. Therefore, according to these configurations, it is possible to suppress an excessive amount of unburned fuel components in the exhaust during sudden acceleration of the internal combustion engine, and it is possible to suitably suppress the generation of white smoke.

  Further, in the configuration of the second aspect, when the internal combustion engine is in an acceleration state during the execution of the increase control, the execution of the increase control is stopped. According to the sixth aspect of the present invention, when the internal combustion engine is accelerated while fuel is being added to the exhaust gas by the addition valve, the fuel addition is stopped. Therefore, according to these structures, generation | occurrence | production of white smoke can be suppressed further reliably.

Hereinafter, an embodiment of an exhaust fuel addition control device according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a configuration of an internal combustion engine 10 to which the present embodiment is applied. The internal combustion engine 10 is a diesel engine including a common rail fuel injection device and a turbocharger 11, and mainly includes an intake passage 12, a combustion chamber 13, and an exhaust passage 14.

  In an intake passage 12 constituting the intake system of the internal combustion engine 10, an air flow meter 16, a compressor 17 of the turbocharger 11, an intercooler 18, And an intake throttle valve 19 is provided. The intake passage 12 is branched at an intake manifold 20 provided on the downstream side of the intake throttle valve 19 and connected to the combustion chamber 13 of each cylinder of the internal combustion engine 10 via an intake port 21.

  On the other hand, in the exhaust passage 14 constituting the exhaust system of the internal combustion engine 10, the exhaust port 22 connected to the combustion chamber 13 of each cylinder is connected to the exhaust turbine 24 of the turbocharger 11 via the exhaust manifold 23. Yes. In addition, a NOx catalytic converter 25, a PM filter 26, and an oxidation catalytic converter 27 are disposed downstream from the exhaust turbine 24 in the exhaust passage 14 in order from the upstream side.

  The NOx catalytic converter 25 carries an NOx storage reduction catalyst. The NOx catalyst stores NOx in the exhaust when the oxygen concentration of the exhaust is high, and releases the stored NOx when the oxygen concentration of the exhaust is low. Further, the NOx catalyst reduces and purifies the released NOx if there is sufficient unburned fuel component as a reducing agent at the time of releasing the NOx.

  The PM filter 26 is formed of a porous material, and PM in exhaust gas is collected. Similarly to the NOx catalytic converter 25, the PM filter 26 also supports an NOx storage reduction catalyst, which purifies NOx in the exhaust gas. Further, the trapped PM is oxidized and removed by a reaction triggered by the NOx catalyst.

The oxidation catalyst converter 27 carries an oxidation catalyst, and HC and CO in the exhaust are oxidized and purified.
In addition, on the upstream side and the downstream side of the PM filter 26 in the exhaust passage 14, an inlet gas temperature sensor 28 that detects the inlet gas temperature that is the temperature of the exhaust gas flowing into the PM filter 26, and the exhaust gas after passing through the PM filter 26. An outgas temperature sensor 29 for detecting an outgas temperature, which is a temperature, is provided. The exhaust passage 14 is provided with a differential pressure sensor 30 for detecting a differential pressure between the exhaust upstream side of the PM filter 26 and the exhaust downstream side thereof. Further, two oxygen sensors 31 and 32 for detecting the oxygen concentration in the exhaust gas are arranged on the exhaust gas upstream side of the NOx catalytic converter 25 in the exhaust passage 14 and between the PM filter 26 and the oxidation catalytic converter 27, respectively. It is installed.

  Further, the internal combustion engine 10 is provided with an exhaust gas recirculation (hereinafter referred to as EGR) device that recirculates a part of the exhaust gas to the air in the intake passage 12. The EGR device includes an EGR passage 33 that allows the exhaust passage 14 and the intake passage 12 to communicate with each other. The most upstream portion of the EGR passage 33 is connected to the exhaust upstream side of the exhaust turbine 24 in the exhaust passage 14. The EGR passage 33 is provided with an EGR catalyst 34 for reforming the recirculated exhaust, an EGR cooler 35 for cooling the exhaust, and an EGR valve 36 for adjusting the flow rate of the exhaust from the upstream side. The most downstream portion of the EGR passage 33 is connected to the downstream side of the intake throttle valve 19 in the intake passage 12.

  On the other hand, a fuel injection valve 40 that injects fuel to be used for combustion in the combustion chamber 13 is disposed in the combustion chamber 13 of each cylinder of the internal combustion engine 10. The fuel injection valve 40 of each cylinder is connected to a common rail 42 via a high pressure fuel supply pipe 41. High pressure fuel is supplied to the common rail 42 through a fuel pump 43. The pressure of the high-pressure fuel in the common rail 42 is detected by a rail pressure sensor 44 attached to the common rail 42.

  Further, low pressure fuel is supplied from the fuel pump 43 to the addition valve 46 through the low pressure fuel supply pipe 45. The addition valve 46 is disposed in the exhaust port 22 of a specific cylinder, injects fuel toward the exhaust turbine 24 side, and adds the fuel into the exhaust.

  The electronic control unit 50 that controls various controls of the internal combustion engine 10 includes a CPU that executes various calculation processes related to the control of the internal combustion engine 10, a ROM that stores programs and data necessary for the control, a calculation result of the CPU, and the like. A RAM that is temporarily stored, an input / output port for inputting / outputting signals to / from the outside, and the like are provided. In addition to the sensors described above, the input port of the electronic control unit 50 includes an NE sensor 51 that detects the engine speed, an accelerator sensor 52 that detects the accelerator operation amount, and a throttle valve sensor that detects the opening of the intake throttle valve 19. 53 etc. are connected. The output port of the electronic control unit 50 is connected to drive circuits such as the intake throttle valve 19, the fuel injection valve 40, the fuel pump 43, the addition valve 46, and the EGR valve 36.

  The electronic control unit 50 outputs a command signal to the drive circuit of each device connected to the output port according to the engine operating state grasped from the detection signal input from each sensor. Thus, the electronic control unit 50 performs various controls such as control of the fuel injection timing and fuel injection amount by the fuel injection valve 40, opening control of the intake throttle valve 19, and EGR control based on the opening control of the EGR valve 36. Has been.

  Further, the electronic control unit 50 performs fuel addition to the exhaust gas by the addition valve 46 as part of such control. The addition of fuel to the exhaust gas by the addition valve 46 is performed in the following controls, that is, PM regeneration control, NOx reduction control, and S poisoning recovery control.

In the PM regeneration control, the PM collected by the PM filter 26 is burned and discharged as carbon dioxide (CO ₂ ) and water (H ₂ O) to eliminate clogging of the PM filter 26. Done. During PM regeneration control, the fuel added to the exhaust from the addition valve 46 is continuously repeated to oxidize the fuel added in the exhaust or on the catalyst, and the catalyst bed temperature is raised by the heat generated by the oxidation reaction. (For example, 600-700 degreeC) WHEREIN: Combustion of the said PM is aimed at.

In the NOx reduction control, NOx occluded in the NOx catalyst of the NOx catalytic converter 25 and the PM filter 26 is reduced to nitrogen (N ₂ ), carbon dioxide (CO ₂ ), and water (H ₂ O) and released. To be done. During NOx reduction control, by intermittently adding fuel from the addition valve 46 to the exhaust after a certain period of time, the exhaust around the NOx catalyst has a temporarily low oxygen concentration and a large amount of unburned fuel components. The so-called rich spike is intermittently performed. As a result, the release and reduction of NOx from the NOx catalyst are promoted to reduce and purify the NOx.

  The S poison recovery control is performed in order to recover the NOx occlusion ability reduced by the sulfur oxide (SOx) occluded together with NOx in the NOx catalyst. When the S poison recovery control is started, first, similarly to the PM regeneration control, the catalyst bed temperature is raised (for example, 600 to 700 ° C.) by continuously adding fuel from the addition valve 46 to the exhaust. The temperature rise control is performed. Thereafter, as in NOx reduction control, intermittent fuel addition from the addition valve 46 is performed, and intermittent rich spikes are performed to promote the release and reduction of SOx from the NOx catalyst, and The NOx occlusion capacity is restored. In this embodiment, the temperature rise control is continued until the PM collected by the PM filter 26 is almost completely purified, so that the catalyst bed temperature is reduced by the combustion of PM simultaneously with the reduction of SOx. The occurrence of excessive temperature rise is prevented.

  Incidentally, in the internal combustion engine 10, the temperature increase multi-injection by the fuel injection valve 40 is performed during the PM regeneration control or during the temperature increase of the catalyst bed temperature in the S poison recovery control. In this temperature rising multi-injection, further fuel injection, that is, after-injection is performed during the compression stroke and exhaust stroke after the pilot injection and the main injection are performed. This after-injection is a sub-injection of fuel different from the injection of fuel used for combustion in the combustion chamber 13 such as pilot injection or main injection. Most of the fuel injected in such after-injection is discharged into the exhaust system without being burned in the combustion chamber 13. For this reason, even when such temperature-increasing multi-injection is performed, the amount of unburned fuel components in the exhaust gas is increased, and the temperature of the catalyst bed is increased.

  As described above, in the present embodiment, the amount of unburned fuel component supplied to the exhaust system catalyst through the addition of fuel to the exhaust gas from the addition valve 46 provided in the exhaust system and the after injection from the fuel injection valve 40 is as follows. Increasing control is performed to increase the amount that is discharged to the exhaust system in association with combustion related to the generation of engine output. Through such increase control, the exhaust gas purification performance of the internal combustion engine 10 is maintained.

However, when such increase control is performed during sudden acceleration of the internal combustion engine 10 such as during no-load racing, a large amount of white smoke may be generated in the exhaust. The reason will be described below.
That is, at the time of rapid acceleration of the internal combustion engine 10, the amount of fuel injected from the fuel injection valve 40 is increased so as to be shared with the combustion in the combustion chamber 13, and the air-fuel ratio of the air-fuel mixture combusted in the combustion chamber 13 Becomes richer than usual. Therefore, at the time of rapid engine acceleration, the amount of unburned components in the exhaust gas is larger than usual without adding fuel from the addition valve 46 to the exhaust gas or performing after injection from the fuel injection valve 40. At this time, if additional unburned fuel components are supplied to the exhaust gas by adding fuel from the addition valve 46 or after-injection, the amount of unburned fuel components in the exhaust gas will be excessive, exceeding the processing capacity of the catalyst. End up. Further, during such rapid acceleration, the amount of exhaust discharged from the combustion chamber 13 is increased, and the flow rate and flow velocity of the exhaust are increased. This tendency is further promoted. For this reason, a large amount of unburned fuel components are discharged without being sufficiently oxidized, and a large amount of white smoke is generated.

  Therefore, in the present embodiment, such generation of white smoke is suppressed by performing the following addition stop control. Specifically, the transition of the engine rotational speed NE is monitored during the fuel addition to the exhaust gas by the addition valve 46. As a result, when it is confirmed that the internal combustion engine 10 is in the accelerated state, The fuel addition is temporarily stopped.

  FIG. 2 shows a routine for a stop determination process for determining whether or not to stop such fuel addition temporarily. The processing of this routine is periodically executed by the electronic control unit 50 as a scheduled interruption process every predetermined time (for example, 65 milliseconds) during the execution of the PM regeneration control, NOx reduction control, and S poison recovery control. Is done.

  When the processing of this routine is started, the electronic control unit 50 first calculates an increase rate ΔNE of the engine speed in step S100. Here, the increase rate ΔNE is obtained from the difference between the engine speed NEOL when the process of the previous routine was executed and the current engine speed NE (ΔNE ← NE−NEOL).

  Next, in step S110, the electronic control unit 50 determines whether or not the internal combustion engine 10 is in an acceleration state based on the calculated engine rotation speed increase rate ΔNE. Specifically, at this time, the electronic control unit 50 determines that the internal combustion engine 10 is in an acceleration state if the increase rate ΔNE is equal to or greater than a predetermined determination value α (for example, 50 rpm), and otherwise, the acceleration state. It is determined that there is not. If the increase rate ΔNE is equal to or greater than the determination value α and the internal combustion engine 10 is in an accelerated state (YES), the electronic control unit 50 advances the process to step S120, turns on the addition stop flag, and performs the process of this routine. Is temporarily terminated. If the increase rate ΔNE is less than the determination value α and the internal combustion engine 10 is not in the acceleration state (S110: NO), the electronic control unit 50 proceeds to step S130 to turn off the addition stop flag and The process is temporarily terminated.

  Thereafter, the electronic control unit 50 sends a fuel addition command signal to the addition valve 46 on condition that the addition stop flag is turned off in the control related to the fuel addition from the addition valve 46. Output. That is, while the addition stop flag is on, fuel addition is not performed even if fuel addition to the exhaust by the addition valve 46 is requested.

  FIG. 3 shows one mode of the addition stop control during PM regeneration control. Normally, during PM regeneration control, fuel addition to the exhaust by the addition valve 46 is periodically performed at every predetermined crank angle β.

  Prior to time t1 in the figure, the internal combustion engine 10 is not in an accelerated state, and the increase rate ΔNE of the engine rotational speed does not exceed the determination value α, so the addition stop flag is turned off. Therefore, the electronic control unit 50 outputs a fuel addition command signal to the addition valve 46 at each crank angle β, and periodically adds fuel from the addition valve 46.

  On the other hand, when the increase rate ΔNE of the engine rotation speed becomes equal to or higher than the determination value α at time t1 in the figure, the addition stop flag is turned on. That is, the internal combustion engine 10 is rapidly accelerated from this time t1, and as described above, white smoke is likely to be generated with the addition of fuel from the addition valve 46.

  At the subsequent time t2, the crank angle β elapses from the previous fuel addition, and it is the timing at which fuel addition should be performed. However, in the example shown in the figure, even at this time t2, the state in which the increase rate ΔNE of the engine speed is equal to or higher than the determination value α is continued, and the addition stop flag remains on. Therefore, at this time t2, the command signal for performing fuel addition is not output, and the fuel addition from the addition valve 46 at this time is stopped. Therefore, the generation of white smoke due to the addition of fuel to the exhaust during the rapid acceleration as described above is avoided.

  Thereafter, when the acceleration of the internal combustion engine 10 ends at time t3 and the increase rate ΔNE of the engine speed falls below the determination value α, the addition stop flag is turned off, and thereafter the periodic fuel addition is performed. Is resumed.

  Incidentally, in the present embodiment, the electronic control unit 50 that performs the control related to the temporary stop of the fuel addition during the rapid acceleration as described above performs the process corresponding to the stop unit. Note that such stopping of fuel addition is synonymous with reducing the amount of fuel added to exhaust to “0”. Therefore, in the present embodiment, the electronic control device 50 also performs a process corresponding to the reduction means.

  As described above, in the exhaust fuel addition control device of the present embodiment, since the fuel addition to the exhaust is stopped during the engine rapid acceleration, the excessive increase of the unburned fuel component in the exhaust is avoided, and the white smoke Generation | occurrence | production can be suppressed suitably. It should be noted that such temporary suspension of fuel addition during engine rapid acceleration is not limited to fuel addition during PM regeneration control as described above, but is similarly performed in fuel addition during NOx reduction control and S poison recovery control. .

The embodiment described above can be implemented with the following modifications.
In the addition stop determination process, it is determined that the internal combustion engine 10 is in an accelerated state based on the transition of the detected value of the engine rotational speed NE. A similar determination may be made based on other control parameters such as the accelerator operation amount and the fuel injection amount. For example, even if it is determined that the internal combustion engine 10 is in an accelerated state when the accelerator operation amount or the fuel injection amount is suddenly increased and fuel addition from the addition valve 46 is stopped, the white state is the same as in the above embodiment. Smoke generation can be suppressed.

  -When the internal combustion engine 10 is in an acceleration state, the generation of white smoke can also be suppressed by reducing the amount of fuel added from the addition valve 46 to the exhaust. That is, even if the fuel addition to the exhaust gas is not reduced to “0”, the fuel addition amount from the addition valve 46 is reduced until the amount of unburned fuel component in the exhaust during engine acceleration becomes equal to or less than the white smoke generation limit. If so, it is possible to avoid the generation of white smoke.

  Instead of stopping and reducing the fuel addition from the addition valve 46, after injection in the temperature rising multi-injection may be stopped, or the fuel injection amount of the after injection may be reduced. Even in such a case, it is possible to suppress an excessive increase of the unburned fuel component in the exhaust accompanying the acceleration of the engine, and the generation of white smoke can be similarly suppressed.

  It is also possible to stop both the fuel addition from the addition valve 46 to the exhaust and the after-injection in the above-mentioned temperature rising multi-injection, or to reduce both the fuel addition amount and the after-injection amount in them. Smoke generation can be suppressed. In short, the supply of unburned fuel components to the catalyst exceeds the amount discharged to the exhaust system of the internal combustion engine 10 in accordance with the combustion related to the generation of engine output through the addition of fuel from the addition valve 46 or the after-injection. The present invention can be applied to any exhaust gas purification apparatus for an internal combustion engine that performs control to increase the amount. And when the internal combustion engine 10 is in an accelerated state during the execution of such control, if the increase in the supply amount due to them is reduced or the increase in the supply amount is stopped, the generation of white smoke is suppressed. Can do.

1 is a schematic diagram showing a configuration of an internal combustion engine to which an embodiment of the present invention is applied and an exhaust purification device thereof. The flowchart of the cancellation determination process applied to the embodiment. The time chart which shows an example of the control which concerns on the fuel addition to exhaust_gas | exhaustion in PM regeneration control in the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Turbocharger, 12 ... Intake passage, 13 ... Combustion chamber, 14 ... Exhaust passage, 15 ... Air cleaner, 16 ... Air flow meter, 17 ... Compressor, 18 ... Intercooler, 19 ... Intake throttle valve, 20 DESCRIPTION OF SYMBOLS ... Intake manifold, 21 ... Intake port, 22 ... Exhaust port, 23 ... Exhaust manifold, 24 ... Exhaust turbine, 25 ... NOx catalytic converter, 26 ... PM filter, 27 ... Oxidation catalytic converter, 28 ... Incoming gas temperature sensor, 29 ... Outgas temperature sensor, 30 ... Differential pressure sensor, 31, 32 ... Oxygen sensor, 33 ... EGR passage, 34 ... EGR catalyst, 35 ... EGR cooler, 36 ... EGR valve, 40 ... Fuel injection valve, 41 ... High pressure fuel supply pipe 42 ... Common rail, 43 ... Fuel pump, 44 ... Rail pressure sensor, 45 ... Low pressure fuel supply pipe, 46 ... Addition valve, 0 ... electronic control unit, 51 ... NE sensor 52: accelerator sensor, 53 ... throttle valve sensor.

Claims (8)

An internal combustion engine that performs an increase control that increases the amount of unburned fuel component supplied to the catalyst disposed in the exhaust system in excess of the amount discharged to the exhaust system of the internal combustion engine in response to combustion related to the generation of engine output In an engine exhaust gas purification device,
The internal combustion engine is in a high back pressure acceleration state, that is, an acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such an extent that white smoke is generated as the back pressure increases. Determination means for determining whether or not the engine is in an acceleration state based on the amount of change in the engine rotational speed;
When it is determined that the engine is in the accelerating state by the judging means, compared and otherwise, reducing means for performing a process for reducing the amount of increase in supply amount of the unburned fuel component in the increase control exhaust purification system of an internal combustion engine, characterized in that it comprises and. An internal combustion engine that performs an increase control that increases the supply amount of the unburned fuel component to the catalyst disposed in the exhaust system in excess of the amount discharged to the exhaust system of the internal combustion engine in accordance with the combustion related to the generation of the engine output In an engine exhaust gas purification device,
The internal combustion engine is in a high back pressure acceleration state, that is, an acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such an extent that white smoke is generated as the back pressure increases. Determination means for determining whether or not the engine is in an acceleration state based on the amount of change in the engine rotational speed;
When it is determined that the engine is in the accelerating state by the judging means, the exhaust gas purifying apparatus for an internal combustion engine, characterized in that it comprises a stop means for processing for stopping the increase control. The exhaust gas purification apparatus for an internal combustion engine according to claim 1 or 2,
The increase control is performed by adding fuel into the exhaust by an addition valve disposed in the exhaust system.
An exhaust emission control device for an internal combustion engine. The exhaust gas purification apparatus for an internal combustion engine according to claim 1 or 2,
The increase control is performed by performing a sub-injection of fuel different from the injection of the fuel provided for the combustion by the fuel injection valve for injecting the fuel provided for the combustion.
An exhaust emission control device for an internal combustion engine. In an exhaust gas purification apparatus for an internal combustion engine, which is provided in an exhaust system of the internal combustion engine and includes an addition valve for adding fuel to the exhaust gas,
The internal combustion engine is in a high back pressure acceleration state, that is, an acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such an extent that white smoke is generated as the back pressure increases. Determination means for determining whether or not the engine is in an acceleration state based on the amount of change in the engine rotational speed;
When it is determined that the engine is in the accelerating state by the judging means, characterized in that it comprises in comparison with otherwise, and reduction means for performing processing to reduce the amount of fuel from the addition valve An exhaust purification device for an internal combustion engine. In an exhaust gas purification apparatus for an internal combustion engine, which is provided in an exhaust system of the internal combustion engine and includes an addition valve for adding fuel to the exhaust gas,
The internal combustion engine is in a high back pressure acceleration state, that is, an acceleration state in which the amount of unburned fuel component in the exhaust gas and the flow rate and flow rate of the exhaust gas increase to such an extent that white smoke is generated as the back pressure increases. Determination means for determining whether or not the engine is in an acceleration state based on the amount of change in the engine rotational speed;
When it is determined that the engine is in the accelerating state by the judging means, the exhaust gas purifying apparatus for an internal combustion engine, characterized in that it comprises a stop means for processing for stopping the implementation of the fuel additive.   The exhaust emission control device for an internal combustion engine according to claim 1 or 5,
  The reduction means always executes the process for reducing the amount of fuel supplied into the exhaust when the determination means determines that the internal combustion engine is in the acceleration state.
  An exhaust emission control device for an internal combustion engine.   The exhaust gas purification apparatus for an internal combustion engine according to claim 2 or 6,
  The stop means always executes the process for stopping the fuel supply into the exhaust when the determination means determines that the internal combustion engine is in the acceleration state.
  An exhaust emission control device for an internal combustion engine.

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