JP2015200199A - Internal combustion engine exhaust emission control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine exhaust emission control system capable of efficiently executing a regeneration control over a filter collecting particulate materials in exhaust gas and a control to remove NOx/SOx from a catalyst, and ensuring satisfactory fuel economy.SOLUTION: An exhaust emission control system 1 comprises an ECU 2. The ECU 2 ends a filter regeneration control at mSot<m3 and temporarily halts the filter regenerative control at mSot≥m3 if total generation time of a state of degrading regeneration efficiency of a filter 7 is equal to or longer than ΔT Cref during execution of the filter regeneration control. The ECU 2 restarts the filter regeneration control at a filter temperature Tf equal to or higher than a predetermined temperature Tf1 if the regeneration control is temporarily halted.

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine that purifies particulate matter, NOx, or SOx in the exhaust gas of the internal combustion engine.

  Conventionally, what was described in patent document 1 is known as an exhaust gas purification apparatus of an internal combustion engine. This exhaust gas purification device purifies exhaust gas in a diesel engine type internal combustion engine, and includes a DPF and a NOx purification catalyst. In the case of this exhaust gas purification device, particulate matter in the exhaust gas is collected by the DPF, and NOx in the exhaust gas is captured by the NOx purification catalyst.

  In this exhaust gas purification apparatus, when the amount of particulate matter accumulated in the DPF reaches a predetermined value, the regeneration control of the DPF is executed for a predetermined time when the operating range of the internal combustion engine is not in the DPF regeneration difficult region. The In this regeneration control, post-injection is executed in order to burn particulate matter deposited on the DPF. On the other hand, when the operating region of the internal combustion engine is in the region where the DPF regeneration is difficult, the regeneration control of the DPF is stopped and the NOx reduction control is executed for a predetermined time in order to reduce the NOx trapped by the NOx purification catalyst. .

Japanese Patent No. 4597876

  According to the exhaust gas purification apparatus for an internal combustion engine disclosed in Patent Document 1, execution / stop of DPF regeneration control is determined according to the operation region of the internal combustion engine, and the combustion state of particulate matter in the DPF is taken into consideration. For this reason, there is a risk that the amount of post-injected fuel for regenerating the DPF becomes excessive, or conversely, it becomes excessive. In that case, when the amount of post-injected fuel is excessive, fuel consumption is deteriorated or oil dilution occurs.

  In addition, since the regeneration control is continued until a predetermined time has elapsed without considering the combustion state of the particulate matter in the DPF after the start of the regeneration control of the DPF, there is a possibility that the regeneration efficiency of the DPF may decrease. There is a risk that the degree of deterioration of fuel consumption and the degree of occurrence of oil dilution will increase.

  Further, even in the NOx reduction control, since the NOx removal state in the NOx purification catalyst is not taken into consideration, when the amount of fuel for controlling the exhaust gas to the reducing atmosphere is excessive, the fuel consumption is deteriorated. In addition, since NOx reduction control is continued until a predetermined time has elapsed without considering the NOx removal state in the NOx purification catalyst after the start of NOx reduction control, the NOx removal efficiency may decrease. At the same time, there is a risk that the degree of deterioration in fuel consumption will increase.

  The present invention has been made to solve the above problems, and can efficiently perform regeneration control of a filter that collects particulate matter in exhaust gas and control of removing NOx / SOx from a catalyst, An object of the present invention is to provide an exhaust gas purification apparatus for an internal combustion engine that can ensure good fuel efficiency.

  In order to achieve the above object, the invention according to claim 1 regenerates the filter 7 by collecting the particulate matter in the exhaust gas of the internal combustion engine 3 by the filter 7 and burning the collected particulate matter. The exhaust gas purifying apparatus 1 of the internal combustion engine 3 includes a soot accumulation amount acquisition means (ECU 2, steps 3, 20, 32) for acquiring a soot accumulation amount mSot that is an accumulation amount of particulate matter in the filter 7, and a filter 7. Regeneration control execution means (ECU2, step 43) for executing regeneration control for regeneration, and regeneration interruption for determining whether or not the state of the filter 7 is in a state where the regeneration control should be interrupted during execution of the regeneration control When the state of the filter 7 is in a state where the regeneration control should be interrupted based on the determination means (ECU 2, steps 13, 20 to 28) and the determination result of the regeneration interruption determination means. When the soot accumulation amount mSot is less than the predetermined value m3, the regeneration end means (ECU2, steps 41 and 44) for ending the regeneration control and the filter 7 are in a state where the regeneration control should be interrupted. When the accumulation amount mSot is equal to or greater than the predetermined value m3, the regeneration interruption means (ECU 2, steps 42 and 44) for temporarily interrupting regeneration control, and the state of the filter 7 when regeneration control is temporarily interrupted Based on the determination result of the regeneration restart determining means (ECU2, steps 12, 14, 30, 31) and the regeneration restart determining means for determining whether or not the regeneration control should be resumed, the state of the filter 7 is regenerated. Regeneration restarting means (ECU2, steps 42 and 43) for restarting the regeneration control when the control is in a state to be resumed is provided.

  According to this exhaust gas purification apparatus for an internal combustion engine, the particulate matter in the exhaust gas from the internal combustion engine is collected by the filter, and the collected particulate matter is burned to regenerate the filter. Further, during the execution of the regeneration control for regenerating the filter, it is determined whether or not the state of the filter is in a state where the regeneration control should be interrupted, and when the state of the filter is in a state where the regeneration control should be interrupted When the soot accumulation amount is less than the predetermined value, the regeneration control is terminated. Accordingly, when the filter is in a state where its regeneration efficiency is lowered, the regeneration control is terminated when the soot accumulation amount is relatively small.

  On the other hand, when the state of the filter is in a state where the regeneration control should be interrupted, when the soot accumulation amount is equal to or greater than a predetermined value, the regeneration control is temporarily interrupted, and thus the regeneration control is temporarily interrupted. If the filter state is in a state where the regeneration control should be resumed, the regeneration control is resumed when the filter state is in a state where the regeneration control should be resumed. As a result, when the soot accumulation amount is relatively large when the filter is in a state where its regeneration efficiency decreases, the regeneration control of the filter is temporarily interrupted, and the filter state is the regeneration efficiency. The playback control is resumed when becomes a good state. As described above, good fuel efficiency can be ensured by executing the filter regeneration control only under the condition of good regeneration efficiency. In addition to this, when post-injection is executed in regeneration control, it is possible to suppress the occurrence of oil dilution (in this specification, “obtain soot deposition amount” and “oxide capture amount”). “Acquisition” in “acquisition” is not limited to directly detecting these values by a sensor or the like, but includes calculating / estimating these values according to other parameters).

  According to a second aspect of the present invention, in the exhaust gas purifying apparatus for the internal combustion engine 3 according to the first aspect, a combustion speed estimating means (ECU2) for estimating a combustion speed of the particulate matter (soot combustion speed BR) during the execution of the regeneration control. Step 22), and the regeneration interruption determination means determines whether or not the state of the filter 7 is in a state where the regeneration control should be interrupted, according to the estimated combustion speed.

  According to the exhaust gas purification apparatus for an internal combustion engine, the combustion speed of the particulate matter during the execution of the regeneration control is estimated, and according to the estimated combustion speed, the state of the filter is in a state where the regeneration control should be interrupted. It is determined whether or not. In this case, the combustion speed of the particulate matter during the execution of the regeneration control appropriately represents the level of the regeneration efficiency of the filter. Therefore, the state of the filter interrupts the regeneration control according to such a combustion speed. By determining whether or not the power is in a high state, high determination accuracy can be ensured, and regeneration efficiency in filter regeneration control can be improved. As a result, even better fuel efficiency can be ensured, and the occurrence of oil dilution can be further suppressed when post injection is performed in regeneration control.

  According to the third aspect of the present invention, the predetermined oxide which is one of NOx and SOx in the exhaust gas of the internal combustion engine 3 is captured by the exhaust gas purification catalyst 6 and removed from the exhaust gas purification catalyst 6 by reducing the captured predetermined oxide. An exhaust gas purification device for an internal combustion engine 3 that performs an oxide trapping amount acquisition means (ECU2, step 51, step 51) for acquiring an oxide trapping amount (NOx trapping amount sNOx) that is a trapping amount of a predetermined oxide in the exhaust gas purification catalyst 6. 70, 82), removal control execution means (ECU2, step 92) for executing removal control for removing the predetermined oxide from the exhaust gas purification catalyst 6, and the state of the exhaust gas purification catalyst 6 during execution of the removal control. The removal interruption determination means (ECU 2, steps 50, 58, 70 to 78) for determining whether or not the removal control should be interrupted, and the determination result of the removal interruption determination means Based on this, when the state of the exhaust gas purification catalyst 6 is in a state where the removal control should be interrupted, the removal ending means for ending the removal control (ECU2, steps 90, 93) when the oxide trapping amount is less than the predetermined value s3. When the exhaust gas purification catalyst 6 is in a state where the removal control should be interrupted, the removal interrupting means (ECU 2, step 91) temporarily interrupts the removal control when the oxide trapping amount is equal to or greater than the predetermined value s3. , 93) and the removal resumption determining means (ECU2, step 57, step 57) for determining whether or not the state of the exhaust gas purification catalyst 6 is in a state where the removal control should be resumed when the removal control is temporarily interrupted. 59, 80, 81) and the resumption of resumption of removal control when the state of the exhaust gas purification catalyst 6 is in a state where resumption control should be resumed based on the determination result of the removal resumption determining means. Stage (ECU 2, step 91, 92), characterized in that it comprises a.

  According to the exhaust gas purification apparatus for an internal combustion engine, the predetermined oxide, which is one of NOx and SOx in the exhaust gas of the internal combustion engine, is captured by the exhaust gas purification catalyst, and the captured predetermined oxide is reduced, thereby reducing the exhaust gas purification catalyst. Removed. Further, during the execution of the removal control for removing the predetermined oxide from the exhaust gas purification catalyst, it is determined whether or not the state of the exhaust gas purification catalyst should be interrupted, and the state of the exhaust gas purification catalyst is removed. When the control is to be interrupted, the removal control is terminated when the oxide trapping amount is less than the predetermined value. Thereby, when the exhaust gas purification catalyst is in a state where the removal efficiency of the predetermined oxide is lowered, the removal control is terminated when the amount of captured oxide is relatively small.

  On the other hand, when the state of the exhaust gas purification catalyst is in a state where the removal control should be interrupted, the removal control is temporarily interrupted when the oxide trapping amount is a predetermined value or more, and the removal control is temporarily When the state of the exhaust gas purification catalyst is interrupted, it is determined whether or not the state of the exhaust gas purification catalyst is to resume the removal control. Resumed. As a result, when the state of the exhaust gas purification catalyst is such that the removal efficiency of the predetermined oxide is reduced, when the oxide trapping amount is relatively large, the removal control of the exhaust gas purification catalyst is temporarily interrupted. When the state of the exhaust gas purification catalyst becomes a state in which the removal efficiency of the oxide trapping amount is good, the removal control is resumed. As described above, good fuel efficiency can be ensured by executing the removal control of the exhaust gas purifying catalyst only under conditions where the removal efficiency of the predetermined oxide is good. In addition, when post injection is performed to remove SOx as the predetermined oxide, the occurrence of oil dilution can be suppressed.

  According to a fourth aspect of the present invention, in the exhaust gas purification apparatus for the internal combustion engine 3 according to the third aspect, a removal rate estimating means (ECU2) for estimating a removal rate (NOx removal rate RS) of a predetermined oxide during execution of the removal control. , Step 72), and the removal interruption determination means determines whether or not the state of the exhaust gas purification catalyst 6 is in a state where the removal control should be interrupted, according to the estimated removal speed. .

  According to the exhaust gas purification apparatus for an internal combustion engine, the removal rate of the predetermined oxide during the execution of the removal control is estimated, and the state of the exhaust gas purification catalyst becomes a state in which the removal control should be interrupted according to the estimated removal rate. It is determined whether or not there is. In this case, the removal rate of the predetermined oxide during the execution of the removal control appropriately represents the level of the removal efficiency of the predetermined oxide in the exhaust gas purification catalyst. Therefore, according to such removal rate, the exhaust gas purification catalyst By determining whether or not this state is a state in which the removal control should be interrupted, high determination accuracy can be ensured, and the removal efficiency in the removal control of the exhaust gas purification catalyst can be improved. As a result, even better fuel efficiency can be ensured, and the occurrence of oil dilution can be further suppressed when post injection is performed to remove SOx as the predetermined oxide.

It is a figure showing typically composition of an exhaust gas purification device concerning a 1st embodiment of the present invention, and an internal-combustion engine to which this is applied. It is a flowchart which shows a filter reproduction | regeneration determination process. It is a flowchart which shows the interruption end determination process. It is a flowchart which shows a restart determination process. It is a flowchart which shows a fuel-injection control process. It is a timing chart which shows an example of the control result by the exhaust gas purification apparatus of 1st Embodiment. It is a timing chart which shows an example of the control result in case the driving load by the exhaust gas purification apparatus of 1st Embodiment differs. It is a flowchart which shows the NOx reduction | decrease determination process by the exhaust gas purification apparatus of 2nd Embodiment. It is a flowchart which shows the interruption end determination process. It is a flowchart which shows a restart determination process. It is a flowchart which shows a fuel-injection control process.

  Hereinafter, an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an exhaust gas purification apparatus 1 of the present embodiment and an internal combustion engine (hereinafter referred to as “engine”) 3 to which the exhaust gas purification apparatus 1 is applied.

  The engine 3 is of a diesel engine type mounted as a power source on a vehicle (not shown), and includes a plurality of cylinders 3a and pistons 3b (only one set is shown). A fuel injection valve 4 is attached to the cylinder head 3c of the engine 3 so as to face the combustion chamber for each cylinder 3a (only one is shown). These fuel injection valves 4 are connected to a high-pressure pump and a fuel tank (both not shown) via a common rail. The fuel boosted by the high-pressure pump is supplied to the fuel injection valve 4 through the common rail, and is injected from the fuel injection valve 4 into the combustion chamber in the cylinder 3a.

  The fuel injection valve 4 is electrically connected to the ECU 2, and the ECU 2 executes fuel injection control processing by controlling the opening / closing timing of the fuel injection valve 4. This fuel injection control process controls the amount and timing of fuel injection by the fuel injection valve 4, and a specific control method will be described later.

  The engine 3 is provided with a crank angle sensor 20. The crank angle sensor 20 includes a magnet rotor and an MRE pickup, and outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3d rotates.

  The CRK signal is output at one pulse every predetermined crank angle (for example, 1 °), and the ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston 3b of each cylinder 3a is at a predetermined crank angle position slightly ahead of the TDC position of the intake stroke, and one pulse is output for each predetermined crank angle.

  On the other hand, the exhaust gas purification device 1 includes an ECU 2, an exhaust gas purification catalyst 6, a filter 7, and the like that are sequentially provided in the exhaust passage 5 of the engine 3 from the upstream side. The exhaust gas purification catalyst 6 is of a type that captures NOx in exhaust gas under an oxidizing atmosphere and reduces the captured NOx under a reducing atmosphere.

  The filter 7 is a CSF (Catalyzed Soot Filter) type, that is, a filter function for collecting particulate matter by adding an oxidation catalyst component to a diesel particulate filter (DPF), and an oxidation function. It is a type that has both.

  Further, a differential pressure sensor 21, a LAF sensor 22, and an exhaust temperature sensor 23 are provided in the exhaust passage 5. The differential pressure sensor 21 is for detecting a differential pressure DPex between the upstream side and the downstream side of the filter 7 in the exhaust passage 5, and includes two detection elements 21a and 21b. The upstream detection element 21 a is provided at a site between the exhaust gas purification catalyst 6 and the filter 7, and the downstream detection element 21 b is provided at a site downstream of the filter 7. The ECU 2 calculates the differential pressure DPex based on the detection signal of the differential pressure sensor 21.

  The LAF sensor 22 is disposed upstream of the exhaust gas purification catalyst 6 and is composed of zirconia, a platinum electrode, and the like, and has a wide range of air-fuel ratio from a rich region richer than the stoichiometric air-fuel ratio to an extremely lean region. In this region, the oxygen amount O2mass and the oxygen concentration O2cn in the exhaust gas flowing in the exhaust passage 5 are detected linearly, and a detection signal representing them is output to the ECU 2. The ECU 2 calculates the oxygen amount O2 mass and the oxygen concentration O2cn based on the detection signal of the LAF sensor 22.

  Further, the exhaust temperature sensor 23 is also disposed between the exhaust gas purification catalyst 6 and the filter 7, detects the temperature of the exhaust gas flowing through the exhaust passage 5, and outputs a detection signal representing it to the ECU 2. The ECU 2 calculates a filter temperature Tf that is the temperature of the filter 7 based on the detection signal of the exhaust temperature sensor 23.

  On the other hand, an accelerator opening sensor 24 and a warning lamp 9 are electrically connected to the ECU 2. The accelerator opening sensor 24 detects a depression amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) of the vehicle, and outputs a detection signal indicating it to the ECU 2.

  Further, the warning lamp 9 is provided in the instrument panel of the vehicle, and when it is determined in the filter regeneration determination process that a large amount of particulate matter is accumulated on the filter 7 as described later, In order to notify the driver of this, the ECU 2 lights up.

  On the other hand, the ECU 2 is composed of a microcomputer including a CPU, RAM, ROM, an I / O interface (all not shown), and the engine 2 according to the detection signals of the various sensors 20 to 24 described above. 3 is determined, and various control processes are executed. Specifically, filter regeneration determination processing, fuel injection control processing, and the like are executed as described below.

  In this embodiment, the ECU 2 corresponds to soot accumulation amount acquisition means, regeneration control execution means, regeneration interruption determination means, regeneration end means, regeneration interruption means, regeneration restart determination means, regeneration restart means, and combustion speed estimation means. To do.

  Next, the filter regeneration determination process will be described with reference to FIG. This filter regeneration determination process determines whether or not the regeneration control process for the filter 7 should be executed, and is executed by the ECU 2 at a predetermined control cycle ΔT (for example, 10 msec). Note that various values calculated or set in the following description are stored in the RAM of the ECU 2.

  As shown in the figure, first, in step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), it is determined whether or not the soot flag F_Sot_NG is “1”. This soot flag F_Sot_NG indicates whether or not a large amount of particulate matter is deposited on the filter 7, and its value is set as described later.

  When the determination result of step 1 is NO, that is, when a large amount of particulate matter has not accumulated on the filter 7 at the previous control timing, the process proceeds to step 2 to check whether the regeneration execution condition flag F_RGN_ON is “1”. Determine whether or not. This regeneration execution condition flag F_RGN_ON indicates whether or not the regeneration control execution condition of the filter 7 is satisfied, and the value thereof is set as described below.

  When the determination result of step 2 is NO, that is, when the execution condition of the regeneration control of the filter 7 is not satisfied at the previous control timing, the process proceeds to step 3 to calculate the soot accumulation amount mSot. The soot accumulation amount mSot is the accumulation amount of the particulate matter in the filter 7, and specifically, is calculated by searching a map (not shown) according to the differential pressure DPex.

  Next, the routine proceeds to step 4 where it is determined whether m2 <mSot <m4 is satisfied. In this case, the values m1 to m5 described in the following description including the two values m2 and m4 are predetermined values of the soot deposition amount mSot set so that m1 <m2 <m3 <m4 <m5 holds. .

  When the determination result in step 4 is YES, the process proceeds to step 5 to determine whether or not the filter temperature Tf is equal to or higher than a predetermined temperature Tf2. The predetermined temperature Tf2 is set to a temperature at which particulate matter deposited on the filter 7 can be burned quickly and efficiently when regeneration control of the filter 7 is executed.

  When the determination result in step 5 is YES, it is determined that the execution condition for the regeneration control of the filter 7 is satisfied, and in order to represent it, the process proceeds to step 6 and the regeneration execution condition flag F_RGN_ON is set to “1”. Then, this process is terminated.

  On the other hand, when the determination result of step 4 or 5 is NO, the process proceeds to step 7, and it is determined whether or not the soot accumulation amount mSot is equal to or larger than a predetermined value m4. When the determination result is NO and mSot <m4 is satisfied, it is determined that the regeneration control execution condition of the filter 7 is not satisfied, and in order to represent it, the process proceeds to Step 8 to indicate the regeneration execution condition flag. After F_RGN_ON is set to “0”, this process ends.

  On the other hand, when the determination result of step 7 is YES, the process proceeds to step 9 to determine whether or not the soot accumulation amount mSot is equal to or greater than a predetermined value m5. When the determination result is NO and m4 ≦ mSot <m5 is satisfied, it is determined that the execution condition for the regeneration control of the filter 7 is satisfied, and after executing step 6 as described above, The process ends.

  On the other hand, when the determination result in step 9 is YES, in order to determine that a large amount of particulate matter has accumulated on the filter 7 so that the regeneration control of the filter 7 cannot be performed, and to inform the driver of this, Proceeding to step 10, the warning lamp 9 is turned on.

  Next, in order to indicate that a large amount of particulate matter has accumulated on the filter 7, in step 11, the soot-rich flag F_Sot_NG is set to “1”, and then this process is terminated. As described above, when the soot flag F_Sot_NG is set to “1” in step 11, the determination result of step 1 described above becomes YES at the next and subsequent control timings, and in this case, the present process is ended as it is. .

  On the other hand, when the determination result of step 2 described above is YES, that is, when the execution condition of the regeneration control of the filter 7 is satisfied at the previous control timing, the process proceeds to step 12 and the regeneration interruption flag F_PAUSE is “1”. It is determined whether or not. This regeneration interruption flag F_PAUSE indicates whether or not the regeneration control of the filter 7 is being suspended, and its value is set as described later.

  When the determination result of step 12 is NO and the regeneration control of the filter 7 is not interrupted, the process proceeds to step 13 to execute the interruption end determination process. This interruption end determination process determines interruption and end of the regeneration control of the filter 7, and is specifically executed as shown in FIG.

  As shown in the figure, first, at step 20, a soot deposition amount mSot is calculated. In this step 20, according to the operating state of the engine 3 (engine speed NE, accelerator pedal opening AP, etc.) and the previous value of the soot accumulation amount mSot stored in the RAM (value calculated at the previous control timing). Then, by calculating the amount of particulate matter estimated to have burned between the previous control timing and the current control timing by a predetermined calculation method, and subtracting this from the previous value of the soot deposition amount mSot, A soot accumulation amount mSot is calculated.

  Next, the routine proceeds to step 21, where it is determined whether or not the soot deposition amount mSot is smaller than a predetermined value m1. When the determination result is YES, it is determined that the regeneration control of the filter 7 should be terminated, and in order to represent this, the process proceeds to step 28, and the regeneration execution condition flag F_RGN_ON is set to “0” and at the same time the regeneration is performed. After the interruption flag F_PAUSE and the count value CT of the reproduction efficiency deterioration counter are also set to “0”, this process ends.

  On the other hand, when the determination result of step 21 is NO and mSot ≧ m1 is established, the routine proceeds to step 22 where the soot combustion speed BR is calculated. This soot combustion speed BR is a speed at which the particulate matter deposited on the filter 7 burns during execution of the regeneration control of the filter 7, and specifically depends on the oxygen amount O2 mass, the filter temperature Tf, and the soot deposition amount mSot. , Calculated by a predetermined calculation method.

  Next, the routine proceeds to step 23, where it is determined whether or not the soot combustion speed BR is equal to or lower than a predetermined speed Bref. The predetermined speed Bref is set to a value indicating that the regeneration efficiency of the filter 7 is deteriorated. When the determination result is NO, the process proceeds to Step 25 described later.

  On the other hand, when the determination result of step 23 is YES, it is determined that the regeneration efficiency of the filter 7 is in a deteriorated state, and the process proceeds to step 24 where the count value CT of the regeneration efficiency deterioration counter is set to the previous value CTz and the value 1 Is set to CTz + 1. That is, the count value CT of the reproduction efficiency deterioration counter is incremented by 1.

  In step 25 following step 23 or 24 described above, it is determined whether or not the count value CT of the reproduction efficiency deterioration counter is smaller than a predetermined value Cref. When the determination result is YES, it is determined that the regeneration control of the filter 7 should be continued, and this processing is ended as it is.

  On the other hand, when the determination result in step 25 is NO, that is, when CT ≧ Cref is satisfied and the total occurrence time in a state where the regeneration efficiency of the filter 7 is deteriorated becomes equal to or larger than the value ΔT · Cref, the process proceeds to step 26. It is determined whether or not the soot accumulation amount mSot is smaller than a predetermined value m3. If the determination result is YES, it is determined that the regeneration control of the filter 7 should be terminated, and as described above, after executing step 28, the present process is terminated.

  On the other hand, when the determination result in step 26 is NO and mSot ≧ m3 is established, the interruption condition for the regeneration control of the filter 7 is established, and the regeneration control of the filter 7 should be temporarily interrupted. In order to determine and represent this, the process proceeds to step 27 where the reproduction interruption flag F_PAUSE is set to “1”, and at the same time, the count value CT of the reproduction efficiency deterioration counter is set to “0”, and then this process is terminated. .

  Returning to FIG. 2, after the interruption end determination process is executed in step 13 as described above, the filter regeneration determination process in FIG.

  On the other hand, when the determination result of step 12 is YES and the regeneration control of the filter 7 is being interrupted, the process proceeds to step 14 to execute the restart determination process. This restart determination process determines whether or not the regeneration control of the suspended filter 7 should be restarted, and is specifically executed as shown in FIG.

  As shown in the figure, first, at step 30, it is determined whether or not the filter temperature Tf is equal to or higher than a predetermined temperature Tf1. The predetermined temperature Tf1 is a temperature at which particulate matter deposited on the filter 7 can be burned quickly and efficiently when the regeneration control of the filter 7 is resumed, and is lower than the predetermined temperature Tf2. Is set.

  When the determination result in step 30 is YES, it is determined that the regeneration control of the filter 7 should be resumed, and in order to represent this, the process proceeds to step 31 and the regeneration interruption flag F_PAUSE is set to “0”. This process is terminated.

  On the other hand, if the determination result in step 30 is NO and Tf <Tf1 is established, the process proceeds to step 32, and the soot deposition amount mSot is calculated by the same method as in step 3 described above.

  Next, the routine proceeds to step 33, where it is determined whether or not the soot deposition amount mSot is equal to or greater than the predetermined value m5 described above. When the determination result is NO and mSot <m5 is established, it is determined that the interruption state of the regeneration control of the filter 7 should be maintained, and this process is terminated as it is.

  On the other hand, when the determination result in step 33 is YES, in order to determine that a large amount of particulate matter has accumulated on the filter 7 so that the regeneration control of the filter 7 cannot be executed, and to inform the driver of this, Proceeding to step 34, the warning lamp 9 is turned on as in step 10 described above.

  Next, in order to indicate that a large amount of particulate matter is accumulated on the filter 7, in step 35, the soot-abundant flag F_Sot_NG is set to “1” in the same manner as in step 11 described above, and then the present process ends. To do.

  Returning to FIG. 2, after the restart determination process is executed as described above in step 14, the filter regeneration determination process in FIG. In addition, you may comprise so that the above restart determination processing may be performed when predetermined time passes from the timing which the reproduction | regeneration control of the filter 7 was interrupted, or when it drive | worked for the predetermined distance.

  Next, the fuel injection control process will be described with reference to FIG. This fuel injection control process controls the amount and timing of fuel injection by the fuel injection valve 4, and is executed by the ECU 2 in synchronism with the generation timing of the TDC signal.

  As shown in the figure, first, in step 40, it is determined whether or not the soot-amount flag F_Sot_NG described above is “0”. If the determination result is YES and a large amount of particulate matter is not deposited on the filter 7, the process proceeds to step 41 to determine whether or not the regeneration execution condition flag F_RGN_ON described above is “1”.

  If the determination result is YES and the execution condition of the regeneration control of the filter 7 is satisfied, the process proceeds to step 42 to determine whether or not the regeneration interruption flag F_PAUSE described above is “0”. If the determination result is YES and the condition for interrupting the regeneration control of the filter 7 is not satisfied, it is determined that the regeneration control of the filter 7 should be executed, and the process proceeds to step 43 to execute the filter regeneration control process.

  In the filter regeneration control process, in addition to the main injection, post injection is executed in order to burn the particulate matter deposited on the filter 7. At that time, the post injection amount and its injection timing are set so that the particulate matter deposited on the filter 7 can be burned quickly and efficiently based on the operating state of the engine 3, the filter temperature Tf, the soot accumulation amount mSot, and the like. It is determined. In step 43, after executing the filter regeneration control process as described above, the present process is terminated.

  On the other hand, when the determination result of any of the steps 40 to 42 described above is NO, that is, when a large amount of particulate matter is accumulated on the filter 7, the execution condition of the regeneration control of the filter 7 is not satisfied, or When the condition for interrupting the regeneration control of the filter 7 is established, the routine proceeds to step 44 where normal control processing is executed. In this normal control process, the fuel injection amount and the injection timing by the fuel injection valve 4 are determined in accordance with the engine speed NE and the accelerator pedal opening AP. In step 44, after executing the normal control process as described above, the present process is terminated.

  Next, an example of a control result (hereinafter referred to as “this control result example”) when various control processes of the present embodiment described above are executed will be described with reference to FIG. In the same figure, the data indicated by the solid line indicates an example of the present control result, and the data indicated by the broken line is an example of the control result when the filter regeneration control is executed by the same technique as that of Patent Document 1 (hereinafter referred to as the following) This is referred to as “comparison control result example”. In the figure, VP represents the vehicle speed, and OD represents the amount of fuel mixed in the engine oil.

  In the example shown in the figure, the various control processes described above are started at time t0. In this case, at time t0, the soot accumulation amount mSot is in the range of m4 ≦ mSot <m5, and the determination result of step 9 described above becomes NO, so that the regeneration execution condition flag F_RGN_ON = 1. At that timing, since the regeneration interruption flag F_PAUSE = 0 and the soot flag F_Sot_NG = 0, the filter regeneration control process in step 43 in FIG. 5 is started.

  Thereafter, the soot accumulation amount mSot decreases with the passage of time, but during the time t0 to t1, the vehicle speed VP is small, and the engine 3 is in a low load operation state, so that the soot combustion speed BR is predetermined. A state where the speed falls below the speed Bref occurs frequently, and accordingly, the count value CT of the reproduction efficiency deterioration counter increases. Then, at the timing when CT ≧ Cref is established (time t1), the soot accumulation amount mSot> m3 is established, and the determination result of step 26 described above becomes NO, so that the regeneration interruption flag F_PAUSE is “1” in step 27. "Is set. As a result, when the determination result of step 42 is NO, the filter regeneration control process is interrupted and the normal control process is executed.

  When the normal control process is executed as described above, the soot accumulation amount mSot increases as the operation time of the engine 3 becomes longer thereafter. Then, at the timing (time t3) when the engine 3 shifts to the high load operation state and the filter temperature Tf ≧ Tf1 is satisfied (time t3), the determination result of step 30 described above becomes YES, so that the regeneration interruption flag F_PAUSE is determined in step 31. Is set to “0”. As a result, when the filter regeneration control process is resumed, the soot accumulation amount mSot starts to decrease, and when the engine 3 is in the high load operation state, the soot combustion speed BR> Bref is established, and the regeneration efficiency deterioration counter is established. The count value CT does not increase.

  Then, as mSot <m1 is established at time t4 as the control proceeds, the determination result in step 21 described above becomes YES, and in step 28, the two flags F_RGN_ON and F_PAUSE are both set to “0”. Is set. Thereby, in the fuel injection control process, the filter regeneration control process ends, and the normal control process is executed.

  On the other hand, in the case of the comparative control result example, the filter regeneration control process is continuously executed after time t0, so that the soot accumulation amount mSot <m1 is established at time t2, and the filter regeneration control process is ended. Therefore, it can be seen that the time required for the filter regeneration control process is shorter than that in the present control result example. However, in the case of the comparative control result example, the post injection amount is increased in order to increase the soot combustion speed BR because the filter regeneration control process is executed even though the engine 3 is in the low load operation state. It can be seen that, due to this, the fuel amount OD mixed in the engine oil is considerably increased as compared with the present control result example. That is, the control result example can execute the filter regeneration control process more efficiently than the comparative control result example, and can secure good fuel consumption and suppress the occurrence of oil dilution. I know that.

  Next, with reference to FIG. 7, a description will be given of control results when various control processes of the present embodiment are executed under conditions where the operation load of the engine 3 is different. In the figure, the data shown by a solid line is an example of a control result at low load operation (hereinafter referred to as “low load example”), and the data shown by a one-dot chain line is an example of a control result at medium load operation (hereinafter referred to as “medium load”). The data indicated by a broken line indicates an example of a control result during high load operation (hereinafter referred to as “high load example”).

  As shown in the figure, in the case of the low load example, the filter regeneration control process is executed after time t10, and CT ≧ Cref & mSot> m3 is established at time t11, as in the case of the present control result example of FIG. As a result, the filter regeneration control process is interrupted. At time t15, when the filter temperature Tf> Tf1 is satisfied, the filter regeneration control process is restarted, and the soot accumulation amount mSot starts to decrease. Then, as mSot <m1 is established at time t16 as the control proceeds, the filter regeneration control process ends.

  In the case of the medium load example, the filter regeneration control process is executed after time t10, and the soot accumulation amount mSot decreases. Then, since the state of BR <Bref continues after time t12, the count value CT of the reproduction efficiency deterioration counter increases, and CT ≧ Cref is satisfied at time t14. At that timing, since the soot accumulation amount mSot <m3 is established, the filter regeneration control process ends in the fuel injection control process, and the normal control process is executed.

  Further, in the case of a high load example, the filter regeneration control process is executed after time t10, and the soot accumulation amount mSot decreases. Then, when the soot accumulation amount mSot <m1 is established at time t13, the filter regeneration control process ends in the fuel injection control process, and the normal control process is executed. As described above, when the engine 3 is in a high load operation or a medium load operation, the soot combustion speed BR is increased as compared with that during the low load operation, so that the filter regeneration control process is continued without being interrupted. It can be seen that it is executed.

  As described above, according to the exhaust gas purification apparatus 1 of the first embodiment, when the determination result of step 5 is YES or the determination result of step 9 is NO, the regeneration execution condition flag F_RGN_ON is set to “1”. As a result, the filter regeneration control process is executed. During the execution of the filter regeneration control process, if the determination result in step 25 is NO, that is, the sum of the occurrence times when the soot combustion speed BR is equal to or lower than the predetermined speed Bref is equal to or greater than the value ΔT · Cref, 7, it is determined that the filter regeneration control process should be interrupted. When the filter regeneration control process is to be interrupted in this way, the filter regeneration control process is terminated when the soot accumulation amount mSot is less than the predetermined value m3. Thereby, when the regeneration efficiency of the filter 7 is deteriorated, the regeneration control is terminated when the soot accumulation amount is relatively small.

  Further, when the filter regeneration control process should be interrupted, the filter regeneration control process is temporarily interrupted when the soot accumulation amount mSot is equal to or greater than the predetermined value m3. When the filter regeneration control process is temporarily interrupted as described above, the filter regeneration control is performed when the filter temperature Tf is equal to or higher than the predetermined temperature Tf1, that is, when the filter 7 can be efficiently regenerated. Processing resumes. Accordingly, when the regeneration efficiency of the filter 7 is deteriorated, when the soot accumulation amount is relatively large, the filter regeneration control process is temporarily interrupted, and the filter 7 is turned off during the suspension of the filter regeneration control process. The filter regeneration control process is resumed when it becomes possible to reproduce efficiently. As described above, the filter regeneration control process is executed only under conditions with good regeneration efficiency, so that good fuel consumption can be ensured and the occurrence of oil dilution can be suppressed.

  Further, during the execution of the filter regeneration control process, the soot combustion speed BR appropriately represents the level of the regeneration efficiency of the filter 7, and the suspension of the filter regeneration control process is determined using such a soot combustion speed BR. Thus, high determination accuracy can be ensured, and the regeneration efficiency of the filter 7 can be improved. As a result, even better fuel efficiency can be ensured, and the occurrence of oil dilution can be further suppressed.

  In addition, although 1st Embodiment is an example using the CSF type filter 7 as a filter, the filter of this invention is not restricted to this, The particulate matter which collected the particulate matter in exhaust gas, and was collected is collected. What is necessary is just to be regenerated by burning a substance. For example, a DPF may be used as a filter.

  The first embodiment is an example in which the predetermined values m1 to m5 of the soot deposition amount mSot are set so that m1 <m2 <m3 <m4 <m5 is satisfied, but the predetermined values m1 to m5 are set to m1 <m2. You may set so that m3 <m2 <m4 <m5 may be materialized.

  Next, an exhaust gas purification apparatus according to the second embodiment will be described. This exhaust gas purifying apparatus captures NOx in the exhaust gas by the exhaust gas purifying catalyst 6, and executes NOx reduction control processing for reducing and removing NOx captured by the exhaust gas purifying catalyst 6.

  In the case of this exhaust gas purifying apparatus, the mechanical configuration and the electrical configuration are the same as those of the exhaust gas purifying apparatus 1 of the first embodiment, and hence the same components are denoted by the same reference numerals and the description thereof is omitted. To do.

  In this embodiment, the ECU 2 serves as an oxide trapping amount acquisition means, a removal control execution means, a removal interruption determination means, a removal end means, a removal interruption means, a removal resumption determination means, a removal resumption means, and a removal speed estimation means. Equivalent to.

  Hereinafter, the NOx reduction determination process will be described with reference to FIG. This NOx reduction determination process determines whether or not the NOx reduction control process should be executed, and is executed by the ECU 2 in the control cycle ΔT described above.

  As shown in the figure, first, at step 50, it is determined whether or not a reduction execution condition flag F_REDUCT is “1”. This reduction execution condition flag F_REDUCT represents whether or not the execution condition for NOx reduction control is satisfied, and its value is set as described below.

  When the determination result of step 50 is NO, that is, when the execution condition of the NOx reduction control is not satisfied at the previous control timing, the process proceeds to step 51 to calculate the NOx trapping amount sNOx. The NOx trapping amount sNOx is the total amount of NOx trapped by the exhaust gas purification catalyst 6, and the NOx trapped between the previous control timing and the current control timing according to the engine speed NE and the accelerator pedal opening AP. It is calculated by calculating the amount and adding it to the previous value of NOx total amount (value calculated at the previous control timing).

  Next, the routine proceeds to step 52, where it is determined whether or not s2 <sNOx <s4 is established. In this case, the values s1 to s4 described in the following description including the two values s2 and s4 are predetermined values of the NOx trapping amount sNOx set so that s1 <s2 <s3 <s4.

  When the determination result of step 52 is YES, the process proceeds to step 53, where it is determined whether or not the catalyst temperature Tc is equal to or higher than a predetermined temperature Tc2. The predetermined temperature Tc2 is set to a temperature at which NOx can be quickly and efficiently removed from the exhaust gas purification catalyst 6 when NOx reduction control is executed.

  When the determination result in step 53 is YES, it is determined that the execution condition of the NOx reduction control is satisfied, and in order to represent it, the process proceeds to step 54 and after the reduction execution condition flag F_REDUCT is set to “1” This process is terminated.

  On the other hand, when the determination result of step 52 or 53 is NO, the process proceeds to step 55, where it is determined whether or not the NOx trapping amount sNOx is equal to or greater than the predetermined value s4. When the determination result is NO and sNOx <s4 is satisfied, it is determined that the execution condition of the NOx reduction control is not satisfied, and in order to represent it, the process proceeds to step 56 and the reduction execution condition flag F_REDUCT is set. After setting to “0”, this process is terminated.

  On the other hand, when the determination result of step 55 is YES, it is determined that the execution condition of the NOx reduction control is satisfied, and after executing step 54 as described above, the present process is terminated.

  On the other hand, when the determination result of step 50 described above is YES, that is, when the execution condition of the NOx reduction control is satisfied at the previous control timing, the process proceeds to step 57, and whether or not the reduction interruption flag F_PAUSE2 is “1”. Is determined. This reduction interruption flag F_PAUSE2 indicates whether or not the NOx reduction control is being interrupted, and its value is set as described later.

  When the determination result of step 57 is NO and the NOx reduction control is not interrupted, the process proceeds to step 58 to execute the interruption end determination process. This interruption end determination process is for determining interruption and end of the NOx reduction control, and is specifically executed as shown in FIG.

  As shown in the figure, first, at step 70, the NOx trapping amount sNOx is calculated. In this step 70, it is estimated that the exhaust gas is removed from the exhaust gas purification catalyst 6 between the previous control timing and the current control timing according to the operating state of the engine 3 (engine speed NE, accelerator pedal opening AP, etc.). The NOx trap amount sNOx is calculated by calculating the NOx amount by a predetermined calculation method and subtracting this from the previous value of the NOx trap amount sNOx.

  Next, the routine proceeds to step 71, where it is determined whether or not the NOx trapping amount sNOx is smaller than a predetermined value s1. When the determination result is YES, it is determined that the NOx reduction control should be terminated, and in order to represent it, the process proceeds to step 78, and at the same time the reduction execution condition flag F_REDUCT is set to “0”, the reduction interruption flag After setting the count value CT2 of F_PAUSE2 and the removal efficiency deterioration counter to “0”, the present process is terminated.

  On the other hand, when the determination result of step 71 is NO and sNOx ≧ s1 is established, the routine proceeds to step 72, where the NOx removal rate RS is calculated. The NOx removal rate RS is a rate at which NOx is removed from the exhaust gas purification catalyst 6 during the execution of the NOx reduction control. Specifically, the NOx removal rate RS is determined according to the oxygen concentration O2cn, the catalyst temperature Tc, and the NOx trapping amount sNOx. It is calculated by a calculation method.

  Next, the routine proceeds to step 73, where it is determined whether or not the NOx removal speed RS is equal to or lower than a predetermined speed Rref. The predetermined speed Rref is set to a value indicating that the NOx removal efficiency is deteriorated. When the determination result is NO, the process proceeds to Step 75 described later.

  On the other hand, when the determination result in step 73 is YES, it is determined that the NOx removal efficiency is in a deteriorated state, the process proceeds to step 74, and the count value CT2 of the removal efficiency deterioration counter is set to the previous value CT2z and the value 1. Set to the sum CT2z + 1. That is, the count value CT2 of the removal efficiency deterioration counter is incremented by 1.

  In step 75 following step 73 or 74 described above, it is determined whether or not the count value CT2 of the removal efficiency deterioration counter is smaller than a predetermined value Cref2. When the determination result is YES, it is determined that the NOx reduction control should be continued, and this process is terminated as it is.

  On the other hand, when the determination result in step 75 is NO, that is, when CT2 ≧ Cref2 is satisfied and the total generation time in the state in which the NOx removal efficiency is deteriorated becomes equal to or larger than the value ΔT · Cref2, the process proceeds to step 76 to capture NOx. It is determined whether or not the amount sNOx is smaller than a predetermined value s3. When the determination result is YES, it is determined that the NOx reduction control should be terminated, and as described above, after executing step 78, the present process is terminated.

  On the other hand, when the determination result of step 76 is NO and sNOx ≧ s3 is satisfied, it is determined that the interruption condition of the NOx reduction control is established, and the NOx reduction control should be temporarily interrupted, In order to represent this, the process proceeds to step 77, where the reduction interruption flag F_PAUSE2 is set to “1” and at the same time the count value CT2 of the removal efficiency deterioration counter is set to “0”, and then this process is terminated.

  Returning to FIG. 8, in step 58, the interruption end determination process is executed as described above, and then the NOx reduction determination process of FIG.

  On the other hand, if the determination result in step 57 is YES and the NOx reduction control is being interrupted, the routine proceeds to step 59, where the restart determination process is executed. This restart determination process determines whether or not the interrupted NOx reduction control should be restarted, and is specifically executed as shown in FIG.

  As shown in the figure, first, at step 80, it is determined whether or not the catalyst temperature Tc is equal to or higher than a predetermined temperature Tc1. The predetermined temperature Tc1 is a temperature at which NOx can be quickly and efficiently removed from the exhaust gas purification catalyst 6 when NOx reduction control is executed, and is set to a temperature lower than the predetermined temperature Tc2. .

  When the determination result in step 80 is YES, it is determined that the NOx reduction control should be resumed, and in order to express this, the process proceeds to step 81, and after setting the reduction interruption flag F_PAUSE2 to “0”, End the process.

  On the other hand, when the determination result of step 80 is NO and Tc <Tc1 is established, the process proceeds to step 82, and the NOx trapping amount sNOx is calculated by the same method as step 51 described above.

  Next, the routine proceeds to step 83, where it is determined whether or not the NOx trapping amount sNOx is greater than or equal to the predetermined value s4 described above. If this determination result is NO and sNOx <s4 is established, this processing is ended as it is.

  On the other hand, when the determination result in step 83 is YES, it is determined that the NOx reduction control should be resumed, and as described above, after executing step 81, the present process is terminated.

  Returning to FIG. 8, in step 59, the restart determination process is executed as described above, and then the NOx reduction determination process of FIG.

  Next, the fuel injection control process will be described with reference to FIG. This fuel injection control process controls the amount and timing of fuel injection by the fuel injection valve 4, and is executed by the ECU 2 in synchronism with the generation timing of the TDC signal.

  As shown in the figure, first, at step 90, it is determined whether or not the above-described reduction execution condition flag F_REDUCT is “1”.

  When the determination result is YES and the execution condition of the NOx reduction control is satisfied, the process proceeds to step 91, and it is determined whether or not the above-described reduction interruption flag F_PAUSE2 is “0”. If the determination result is YES and the interruption condition of the NOx reduction control is not established, it is determined that the NOx reduction control should be executed, the process proceeds to step 92, and the NOx reduction control process is executed.

  In this NOx reduction control process, the fuel injection amount and the injection timing of the fuel injection valve 4 are controlled so that the exhaust gas becomes a reducing atmosphere. At that time, based on the operating state of the engine 3, the catalyst temperature Tc, the NOx trapping amount sNOx, and the like, the fuel injection amount and the injection timing are determined so that NOx can be quickly and efficiently removed from the exhaust gas purification catalyst 6. The In step 92, after executing the NOx reduction control process as described above, the present process is terminated.

  On the other hand, when the determination result of any one of steps 90 and 91 is NO, that is, when the execution condition for NOx reduction control is not satisfied, or when the interruption condition for NOx reduction control is satisfied, the process proceeds to step 93. The normal control process is executed. In this normal control process, the fuel injection amount and the injection timing by the fuel injection valve 4 are determined in accordance with the engine speed NE and the accelerator pedal opening AP. In step 93, after executing the normal control process as described above, the present process is terminated.

  As described above, according to the exhaust gas purifying apparatus of the second embodiment, when the determination result of step 53 or step 55 is YES, the reduction execution condition flag F_REDUCT is set to “1”, so that the NOx reduction control process is performed. Is executed. During the execution of this NOx reduction control process, if the determination result in step 75 is NO, that is, the total sum of occurrence times when the NOx removal speed RS is equal to or lower than the predetermined speed Rref becomes equal to or greater than the value ΔT · Cref2, When the state where the reduction efficiency deteriorates frequently, it is determined that the NOx reduction control process should be interrupted. When the NOx reduction control process is to be interrupted in this way, the NOx reduction control process is ended when the NOx trapping amount sNOx is less than the predetermined value s3. Thereby, when the NOx reduction efficiency is in a deteriorated state, the regeneration control is terminated when the NOx trapping amount sNOx is relatively small.

  Further, when the NOx reduction control process should be interrupted, the NOx reduction control process is temporarily interrupted when the NOx trapping amount sNOx is equal to or greater than the predetermined value s3. When the NOx reduction control process is temporarily interrupted as described above, the NOx reduction control process is performed when the catalyst temperature Tc is equal to or higher than the predetermined temperature Tc1, that is, when the NOx can be efficiently reduced. Is resumed. As a result, when the NOx reduction efficiency is deteriorated and the NOx trapping amount sNOx is relatively large, the NOx reduction control process is temporarily interrupted, and NOx is efficiently removed during the interruption of the NOx reduction control process. When the fuel can be reduced, the NOx reduction control process is resumed. As described above, good fuel efficiency can be ensured by executing the NOx reduction control process only under conditions with good NOx reduction efficiency.

  Further, during the execution of the NOx reduction control process, the NOx removal rate RS appropriately represents the level of the NOx reduction efficiency, and by using such a NOx removal rate RS, it is determined that the NOx reduction control process is interrupted. High determination accuracy can be ensured, and NOx reduction efficiency can be improved. As a result, even better fuel efficiency can be ensured.

  Note that the second embodiment is an example in which NOx as a predetermined oxide captured by the exhaust gas purification catalyst 6 is reduced and controlled. In order to remove from the purification catalyst 6, SOx reduction control may be executed. In that case, the SOx reduction determination process and the fuel injection control process may be executed by a method similar to the control process of FIGS.

  When SOx reduction control is executed in this way, in the fuel injection control process, air-fuel ratio enrichment control and post-injection control for controlling the exhaust gas to the reducing atmosphere are alternately performed. Therefore, like the NOx reduction control described above, the SOx reduction control is executed only under conditions with good SOx reduction efficiency, so that good fuel consumption can be ensured and the occurrence of oil dilution is suppressed. be able to. In addition to this, by using the SOx removal speed to determine the interruption of the SOx reduction control process, high determination accuracy can be ensured and SOx reduction efficiency can be improved. As a result, even better fuel efficiency can be ensured, and the occurrence of oil dilution can be further suppressed.

  The second embodiment is an example in which the exhaust gas is controlled to a reducing atmosphere by increasing the fuel injection amount as the NOx reduction control processing, but instead, by increasing the EGR amount by the EGR device. The exhaust gas may be controlled to a reducing atmosphere.

  Furthermore, although 2nd Embodiment is an example which used the exhaust gas purification catalyst 6 as a catalyst, the catalyst of this invention is not restricted to this, By capturing NOx / SOx and reducing the captured NOx / SOx, What is necessary is just to remove. For example, a diesel oxidation catalyst or a three-way catalyst may be used as the catalyst.

  On the other hand, the first and second embodiments are examples in which a diesel engine type is used as the internal combustion engine, but the internal combustion engine of the present invention is not limited to this, and may be an internal combustion engine such as a gasoline engine or a natural gas engine. That's fine.

  Moreover, although 1st and 2nd embodiment is an example which applied the exhaust gas purification apparatus to the internal combustion engine for vehicles, the exhaust gas purification apparatus of this invention is not restricted to this, The internal combustion engine for ships, and other industries The present invention is also applicable to an internal combustion engine for equipment.

DESCRIPTION OF SYMBOLS 1 Exhaust gas purification apparatus 2 ECU (Soot accumulation amount acquisition means, regeneration control execution means, regeneration interruption determination means, regeneration termination means, regeneration interruption means, regeneration restart determination means, regeneration restart means, combustion speed estimation means, oxide trapping amount Acquisition means, removal control execution means, removal interruption determination means, removal end means, removal interruption means, removal resumption determination means, removal resumption means, removal speed estimation means)
3 Internal combustion engine 6 Exhaust gas purification catalyst 7 Filter mSot Soot accumulation m3 Predetermined value BR Soot burning rate (burning rate of particulate matter)
sNOx NOx trapping amount (oxide trapping amount)
s3 Predetermined value RS NOx removal rate (predetermined oxide removal rate)

Claims (4)

An exhaust gas purification apparatus for an internal combustion engine that collects particulate matter in exhaust gas of an internal combustion engine with a filter and regenerates the filter by burning the collected particulate matter,
Soot accumulation amount acquisition means for acquiring a soot accumulation amount which is an accumulation amount of the particulate matter in the filter;
Regeneration control executing means for executing regeneration control for reproducing the filter;
During execution of the regeneration control, regeneration interruption determination means for determining whether or not the state of the filter is in a state where the regeneration control should be interrupted;
Based on the determination result of the regeneration interruption determining means, the regeneration ending means for ending the regeneration control when the soot accumulation amount is less than a predetermined value when the state of the filter is in a state where the regeneration control should be interrupted. When,
When the state of the filter is in a state where the regeneration control should be interrupted, regeneration interruption means for temporarily interrupting the regeneration control when the soot accumulation amount is equal to or greater than the predetermined value;
When the regeneration control is temporarily interrupted, regeneration restart determining means for determining whether the state of the filter is in a state where the regeneration control should be restarted;
An exhaust gas for an internal combustion engine, comprising: a regeneration restarting unit that restarts the regeneration control when the state of the filter is in a state where the regeneration control should be restarted based on a determination result of the regeneration restart determining unit Purification equipment. Further comprising a combustion rate estimating means for estimating a combustion rate of the particulate matter during execution of the regeneration control,
2. The internal combustion engine according to claim 1, wherein the regeneration interruption determination unit determines whether or not the state of the filter is in a state in which the regeneration control should be interrupted according to the estimated combustion speed. Engine exhaust gas purification equipment. An exhaust gas purification apparatus for an internal combustion engine that captures a predetermined oxide, which is one of NOx and SOx, in an exhaust gas of an internal combustion engine by an exhaust gas purification catalyst and removes the captured predetermined oxide from the exhaust gas purification catalyst. And
An oxide trapping amount acquisition means for acquiring an oxide trapping amount that is the trapping amount of the predetermined oxide in the exhaust gas purification catalyst;
Removal control execution means for executing removal control for removing the predetermined oxide from the exhaust gas purification catalyst;
A removal interruption determination means for determining whether or not the state of the exhaust gas purification catalyst is in a state where the removal control should be interrupted during execution of the removal control;
Based on the determination result of the removal interruption determination means, when the state of the exhaust gas purification catalyst is in a state where the removal control should be interrupted, the removal control is ended when the oxide trapping amount is less than a predetermined value. Removal termination means;
In the case where the state of the exhaust gas purification catalyst is in a state where the removal control should be interrupted, a removal interrupting means for temporarily interrupting the removal control when the oxide trapping amount is a predetermined value or more,
In the case where the removal control is temporarily interrupted, a removal restart determination means for determining whether or not the state of the exhaust gas purification catalyst is in a state where the removal control should be restarted;
An internal combustion engine comprising: a removal resuming unit that resumes the removal control when the state of the exhaust gas purification catalyst is in a state where the removal control should be resumed based on a determination result of the removal resumption determination unit. Exhaust gas purification equipment. A removal rate estimating means for estimating a removal rate of the predetermined oxide during execution of the removal control;
The said removal interruption determination means determines whether or not the state of the exhaust gas purification catalyst is in a state where the removal control should be interrupted, according to the estimated removal speed. Exhaust gas purification device for internal combustion engine.

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