JP2008031854A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine capable of regenerating a filter at an appropriate timing. <P>SOLUTION: The device is equipped with a diesel particulate filter 23 for collecting particulates in exhaust, a temperature sensor 26 for detecting temperature of the filter 23 at regeneration, and an ECU 31 including a correction means for correcting a determination value for determining subsequent timings for regenerating the diesel particulate filter 23 based upon a prescribed parameter value on the basis of the highest temperature of the diesel particulate 23 detected by the temperature sensor 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification device for an internal combustion engine, and more particularly to an exhaust gas purification device for an internal combustion engine that accurately regenerates a diesel particulate filter that collects particulates contained in exhaust gas from the internal combustion engine.

  In addition to HC (hydrocarbon), CO (carbon monoxide), and NOx (nitrogen oxide), exhaust gas exhausted from diesel engines and the like includes particulate matter (PM) such as soot that is fine particles. Yes. Therefore, the exhaust system of an internal combustion engine such as an automobile has a built-in filter for collecting particulate matter, and an exhaust gas purification device for the internal combustion engine is provided as a device for burning and removing soot in the collected particulate matter. It has been.

  In the above-described exhaust gas purification apparatus for an internal combustion engine, when the accumulation of soot collected by the filter reaches a predetermined amount, the regeneration process of the filter is forcibly performed. Here, when the filter regeneration process is performed, the amount of soot accumulation cannot be measured. Therefore, it is estimated by various methods, and the filter regeneration process is performed based on the estimated soot accumulation amount. (Spacing) is adjusted. As the estimation method of the amount of soot accumulation described above, there are currently a method of estimating from the travel distance based on the vehicle speed, a method of estimating from the differential pressure before and after the filter, and a method of estimating from the rotational speed and load of the internal combustion engine. .

  Further, as the exhaust gas purification device for the internal combustion engine described above, the pressure upstream of the filter that collects exhaust particles contained in the exhaust gas is detected, and when this pressure exceeds a predetermined value, it is determined that it is the regeneration time, The engine is designed to heat up the filter and perform regeneration, and correct the exhaust pressure to be increased as the maximum temperature of the filter at the time of regeneration is lower or the time to reach the maximum temperature is shorter. An exhaust particulate processing apparatus is known (see, for example, Patent Document 1). That is, in this apparatus, the amount of accumulated ash accumulated (collected) in the filter is estimated from the maximum temperature during the filter regeneration process and the time to reach this temperature, and the exhaust pressure during the next filter regeneration process is estimated. The ash is forcibly discharged to keep the collecting power of the exhaust particulates of the filter constant.

Japanese Patent No. 3663729

However, each of the accumulation amount estimation methods described above has the following problems, for example.
In the estimation method based on the travel distance, the amount of soot discharged may be different even when the travel distance is the same due to an operation with a large acceleration / deceleration difference or due to individual differences of the internal combustion engine. Therefore, the amount of soot collected by the filter cannot be accurately estimated, and there is a possibility that the filter regeneration process cannot be performed accurately.

  In the estimation method based on the differential pressure before and after the filter, uneven accumulation with different accumulation amounts of soot occurs in the front-rear direction of the filter, the accumulation amount of soot collected due to individual differences in the filter, or the ash content contained in the exhaust gas When the amount of soot differs depending on the exhaust gas discharge timing, the soot accumulation estimated by the differential pressure may not be close to the soot accumulation actually collected by the filter. As a result, there is a possibility that the filter regeneration process cannot be performed accurately.

  In the estimation method based on the number of revolutions and load of the internal combustion engine, excessive exhaust of exhaust gas due to sudden start or deceleration, temperature rise of exhaust gas at that time, individual differences of internal combustion engines, etc. Therefore, there is a possibility that the accumulation amount of the filter cannot be accurately estimated and the filter regeneration process cannot be performed accurately.

  In the engine exhaust particle processing apparatus described in Patent Document 1, the ash accumulated in the filter is forcibly discharged to suppress a decrease in the collection power of the exhaust particle of the filter due to the ash collected in the filter. Although it is possible to accurately correct the error in the regeneration timing of the filter, the accumulation amount of exhaust particulates differs in the front-rear direction of the filter, and the accumulation amount of trapped soot varies depending on individual differences in the filter. In such a case, the accumulated amount of exhaust particulates estimated by the differential pressure may not be close to the accumulated amount of exhaust particulates actually collected by the filter. As a result, there is a possibility that the filter regeneration process cannot be performed accurately.

  The present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide an exhaust gas purification apparatus for an internal combustion engine that can accurately determine the regeneration processing timing of the filter.

  An exhaust gas purification apparatus for an internal combustion engine according to a first aspect of the present invention that solves the above-described problem includes a filter that collects particulates in exhaust gas, and a timing for regenerating the filter based on a predetermined parameter value. Filter regeneration means for regenerating the filter, filter temperature detection means for detecting the temperature of the filter during the regeneration process by the filter regeneration means, and the next and subsequent regeneration processes based on the maximum temperature of the filter detected by the filter temperature detection means Correction means for correcting the determination value of the time determination.

  An exhaust gas purification apparatus for an internal combustion engine according to a second invention that solves the above-described problems is the exhaust gas purification apparatus for an internal combustion engine described in the first invention, wherein the correction means is predetermined as the maximum temperature. The correction amount of the determination value is determined according to the difference from the reference maximum temperature.

  An exhaust gas purification apparatus for an internal combustion engine according to a third invention for solving the above-described problem is the exhaust gas purification apparatus for an internal combustion engine described in the second invention, wherein the correction means has the maximum temperature as the reference maximum. When the temperature is higher than the temperature, the determination value is corrected so that the regeneration processing interval of the filter is shortened. When the maximum temperature is lower than the reference maximum temperature, the regeneration processing interval is lengthened. The determination value is corrected.

  An exhaust gas purifying apparatus for an internal combustion engine according to a fourth invention for solving the above-described problem is the exhaust gas purifying apparatus for an internal combustion engine described in any one of the first to third inventions, wherein the filter regeneration means includes: The determination value is set with the predetermined parameter value as at least one of a travel distance of a vehicle on which the internal combustion engine is mounted, a differential pressure before and after the filter, and a rotation speed and a load of the internal combustion engine. To do.

  According to the exhaust gas purification apparatus for an internal combustion engine according to the first aspect of the present invention, by correcting the determination value for determining the next filter regeneration process time based on the maximum filter temperature during the filter regeneration process, The filter can be regenerated at an appropriate time by reducing the influence of the estimation error of the accumulation amount due to the difference, the deviation of the fine particles accumulated on the filter (uneven accumulation), the variation in the amount of fine particles in the exhaust gas, and the like.

  According to the exhaust gas purification apparatus for an internal combustion engine according to the second aspect of the invention, the time for regenerating the filter is determined according to the difference between the maximum temperature of the filter when the filter is regenerated and a predetermined reference maximum temperature. By determining the correction amount of the determination value to be performed, the filter can be regenerated at a more appropriate time.

  According to the exhaust gas purification apparatus for an internal combustion engine according to the third aspect, when the maximum temperature is higher than the reference maximum temperature, the next regeneration is performed by correcting the determination value so that the regeneration processing interval of the filter is shortened. The possibility of causing excessive temperature rise of the filter during processing can be reduced. Furthermore, when the maximum temperature is lower than the reference maximum temperature, the possibility that the next regeneration processing time is advanced and fuel consumption deteriorates can be reduced by correcting the determination value so that the regeneration processing interval becomes longer. .

  According to the exhaust gas purification apparatus for an internal combustion engine according to the fourth aspect of the present invention, the determination value is set with the travel distance as a predetermined parameter value, so that the next time even when the soot discharge amount is different at the same travel distance, etc. The subsequent reproduction processing time can be accurately determined. In addition, by setting a judgment value using the differential pressure as a predetermined parameter, the next and subsequent regeneration processing timings can be accurately determined even when uneven deposition occurs in the filter or when there is a difference in collection power due to individual differences in the filter. Can be determined. Furthermore, even if there is a difference in exhaust gas emissions or temperature rise due to sudden start or sudden deceleration, individual differences among internal combustion engines, etc., by setting a judgment value with the rotation speed and load as predetermined parameter values Thus, it is possible to accurately determine the playback processing time after the next time.

  Hereinafter, the best mode for carrying out an exhaust gas purification apparatus for an internal combustion engine according to the present invention will be specifically described based on examples.

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 is a schematic configuration diagram of an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a flowchart showing filter regeneration control executed in the exhaust gas purification apparatus. FIG. 3 is a graph showing the regeneration processing interval of the filter included in the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention, where the horizontal axis indicates time and the vertical axis indicates the filter temperature. FIG. 4 is a graph showing the relationship between the maximum temperature during regeneration control and the amount of soot accumulation in the filter of the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention.

  In this embodiment, as shown in FIG. 1, a diesel engine 1 is employed as an internal combustion engine main body, in which fuel such as light oil is directly injected into air that has been heated to a high temperature by high compression, and is spontaneously ignited for combustion.

  The cylinder head 2 of the diesel engine 1 is provided with an electromagnetic fuel injection nozzle 3 facing the combustion chamber 4 for each cylinder, and the fuel injection nozzle 3 is connected to a common rail 6 by a high-pressure pipe 5. The common rail 6 is connected to a fuel tank 8 by a high-pressure pipe 7, and a high-pressure pump 9 is disposed in the middle of the high-pressure pipe 7.

  An intake port 10 and an exhaust port 12 are formed in the cylinder head 2 for each cylinder. An intake pipe (intake passage) 11 is connected via an intake manifold (not shown) so as to communicate with each intake port 10. Further, an exhaust pipe (exhaust passage) 13 is connected to each exhaust port 12 through an exhaust manifold (not shown). The front ends of the intake valve 14 and the exhaust valve 15 respectively face the intake ports 10 and the exhaust ports 12, and the combustion chamber 4 and the ports 10 and 12 are opened and closed.

  The intake pipe 11 is provided with an electromagnetic intake throttle valve 16 that adjusts the intake air amount. Further, an air flow sensor 17 for measuring the intake air amount Qa is attached.

  An EGR pipe 18 is connected to the exhaust pipe 13, and a terminal end of the EGR pipe 18 is connected to the intake pipe 11. An electromagnetic EGR valve 19 is disposed in the middle of the EGR pipe 18.

An exhaust gas purification device main body 20 is interposed in the exhaust pipe 13. The exhaust gas purification device main body 20 includes first and second oxidation catalysts 21 and 22 arranged in series, and a diesel particulate filter (DPF) 23 arranged on the downstream side of the second oxidation catalyst 22. Have. In the exhaust gas purifying apparatus main body 20, oxidant (NO ₂ ) is generated in the first and second oxidation catalysts 21, 22, and soot accumulated on the downstream diesel particulate filter 23 by the generated oxidant is continuously continuous. It is configured to oxidize and remove.

  First, second, and third temperature sensors (temperature measurement) are provided upstream of the first oxidation catalyst 21, between the first oxidation catalyst 21 and the second oxidation catalyst 22, and downstream of the diesel particulate filter 23. Means) 24, 25 and 26 are provided. In each sensor 24, 25, 26, the temperature of the exhaust gas introduced into the first oxidation catalyst 21, the temperature of the exhaust gas introduced into the second oxidation catalyst 22, and the exhaust gas exhausted from the diesel particulate filter 23 The temperature (the temperature of the diesel particulate filter 23) is detected. Further, in the exhaust pipe 13, the pressure of exhaust gas upstream of the diesel particulate filter 23 (exhaust gas introduced into the diesel particulate filter 23) and exhaust gas downstream of the diesel particulate filter 23 (diesel particulate filter 23). A DPF differential pressure sensor (differential pressure measuring means) 27 for detecting a differential pressure with respect to the pressure of the exhaust gas exhausted from the exhaust gas is provided.

  The vehicle is provided with an ECU 31 that is an electronic control unit of the engine. In the ECU 31, on the input side, an air flow sensor 17, first, second and third temperature sensors 24, 25 and 26, a DPF differential pressure sensor 27, a crank angle sensor 28 for detecting a crank angle, and an accelerator position sensor 29 are provided. A vehicle speed sensor 30 which is a vehicle speed measuring means for measuring the speed of the vehicle is connected, and detection information from these sensors is input. A crank angle sensor (rotational speed measuring means) 28 can detect the rotational speed of the internal combustion engine. On the other hand, the fuel injection nozzle 3, the intake throttle valve 16, and the like are connected to the output side of the ECU 31, and the fuel injection nozzle 3, the intake throttle valve 16, and the like are based on detection information from various sensors. Optimum values such as the calculated fuel injection amount and throttle opening th are output. Thereby, an appropriate amount of fuel is injected from the fuel injection nozzle 3 at an appropriate timing.

  The ECU 31 includes an input / output device, a storage device (ROM, RAM, BURRAM, etc.) for storing a control program and a control map, a central processing unit (CPU), a timer and counters. Overall control of the engine 1 is performed.

  Thereby, various devices are controlled based on various input information, and the engine 1 is appropriately controlled. Further, the ECU 31 performs the main injection for the main combustion by the fuel injection nozzle 3 and then performs the additional supply of fuel, that is, the post injection by the fuel injection nozzle 3 in the expansion stroke or the exhaust stroke, so that the diesel particulate filter The diesel particulate filter 23 can be regenerated by forcibly burning and removing the soot collected in the cylinder 23.

  Therefore, when the diesel particulate filter 23 cannot perform the continuous regeneration function under normal operating conditions, the oxidation reaction between unburned fuel (HC, CO, etc.) by post injection and oxygen in the exhaust is oxidized. The oxidation catalysts 21 and 22 are activated by being promoted on the catalysts 21 and 22. Then, it is possible to forcibly burn and remove the soot accumulated on the diesel particulate filter 23 by raising the temperature of the diesel particulate filter 23 by the heat of the oxidation reaction generated at this time.

  In the present embodiment, the ECU 31 determines the timing for regenerating the filter 23 based on a predetermined parameter value, here, the travel distance of the vehicle on which the diesel engine 1 is mounted, and regenerates the diesel particulate filter 23. And a determination value for determining the regeneration processing time of the diesel particulate filter 23 based on the maximum temperature of the filter 23 measured by the third temperature sensor 26 (determination value for determining the timing for regeneration processing of the diesel particulate filter 23). Correction means for correcting. Specifically, the ECU 31 performs forced regeneration control of the diesel particulate filter 23 based on the flowchart shown in FIG.

  First, in step S11, it is determined whether the travel distance calculated from the vehicle speed detected by the vehicle speed sensor 30 is greater than the regeneration start distance (determination value). That is, the amount of soot collected by the diesel particulate filter 23 is calculated from the travel distance and estimated. If the travel distance is greater than the regeneration start distance, the process proceeds to step S12, and if the travel distance is equal to or smaller than the regeneration start distance, the process ends.

  In step S12, regeneration control of the diesel particulate filter 23 is performed. That is, in order to forcibly regenerate the diesel particulate filter 23, the soot collected by the diesel particulate filter 23 by the post injection described above is burned and removed.

  Then, it progresses to step S13. In this step, the maximum temperature during the regeneration process of the diesel particulate filter 23 is measured by the third temperature sensor 26.

  Then, it progresses to step S14. In this step, the end of the regeneration control of the diesel particulate filter 23 is determined. That is, before a predetermined time has elapsed since the start of regeneration control of the diesel particulate filter 23, the process returns to step S12, and after the predetermined time has elapsed since the start of regeneration control of the diesel particulate filter 23, the diesel particulate filter The regeneration control (post injection) of the filter 23 is finished, and the process proceeds to Step S15.

  In step S15, the next reproduction start distance is calculated, and the process ends. That is, the next diesel particulates calculated from the difference between the maximum temperature during the regeneration process of the diesel particulate filter this time and the reference maximum temperature (predetermined reference maximum temperature) Tf when a predetermined amount of soot burns. The correction amount of the regeneration start distance of the curate filter 23 (the correction amount of the determination value determined according to the difference between the maximum temperature and the reference maximum temperature Tf), the regeneration start distance of the previous diesel particulate filter 23, and From this, the regeneration start distance of the next diesel particulate filter 23 is calculated, and the process ends.

  Specifically, the next regeneration processing interval (regeneration start distance) DIST2 of the diesel particulate filter 23 is the previous regeneration processing interval (regeneration processing distance) DIST1 of the diesel particulate filter 23, and the current diesel particulate filter 23. The following equation (1) is derived from the difference ΔTEMP between the maximum temperature during the regeneration process and the reference maximum temperature Tf. In other words, the fact that the maximum temperature during the regeneration process is higher than the reference maximum temperature means that a larger amount of soot has burned than the reference, and from this, the diesel particulate filter 23 has a larger amount of soot than the reference. It can be estimated that it was deposited. On the contrary, the fact that the maximum temperature during the regeneration process is lower than the reference maximum temperature means that a smaller amount of soot has burned than the reference, and thus the diesel particulate filter 23 has a smaller amount of soot than the reference. Can be estimated.

  DIST2 = DIST1 + f (ΔTEMP) (1)

  However, when the maximum temperature during the regeneration process of the diesel particulate filter 23 is higher than the reference maximum temperature Tf, f (ΔTEMP) is a negative value, and is calculated from the estimated accumulation amount of soot based on the travel distance. From the previous filter regeneration process interval DIST1 from the previous regeneration process of the diesel particulate filter 23 to the regeneration process of the current diesel particulate filter 23, from the regeneration process of the current diesel particulate filter 23 to the next diesel particulate filter The next filter regeneration processing interval DIST2 up to 23 regeneration processing is calculated to be short. On the other hand, when the maximum temperature during the regeneration process of the diesel particulate filter 23 is lower than the reference maximum temperature Tf, f (ΔTEMP) becomes a positive value, and the next filter regeneration is performed from the previous filter regeneration processing interval DIST1. Calculation is performed so that the processing interval DIST2 becomes longer. Further, when the maximum temperature during the regeneration process of the diesel particulate filter 23 is the same as the reference maximum temperature Tf, f (ΔTEMP) becomes zero, and the previous time calculated from the estimated accumulation amount of soot based on the travel distance The filter regeneration processing interval DIST1 and the next filter regeneration processing interval DIST2 are calculated to have the same value.

  For example, in the time chart as shown in FIG. 3, the maximum temperature is higher than the reference maximum temperature Tf, and it can be determined that the actual amount of accumulated soot is larger than the reference predetermined amount (see FIG. 4 described later). Therefore, correction is performed with a value f (ΔTEMP) (in this case, a negative value) corresponding to the difference ΔTEMP between the maximum temperature and the reference maximum temperature Tf. As a result, in the case of FIG. 3, DIST2 is shorter than DIST1.

  The maximum temperature during the regeneration process of the diesel particulate filter 23 and the amount of soot collected by the diesel particulate filter 23 can be expressed by a linear curve, for example, as shown in FIG. There is a relationship that the higher the temperature, the greater the amount of soot accumulated.

  Therefore, according to the exhaust gas purification apparatus 50 for an internal combustion engine according to the first embodiment of the present invention, the difference ΔTEMP between the maximum temperature during the regeneration processing of the diesel particulate filter 23 and the reference maximum temperature Tf is used, and the above-described equation From (1), the next filter regeneration processing interval DIST2 can be accurately determined. As a result, when the amount of soot accumulation is estimated to be less than the actual amount, the possibility that the diesel particulate filter 23 may be damaged due to excessive increase in the processing temperature due to excessive increase in the processing temperature can be reduced. Further, when the amount of soot accumulated is estimated to be larger than the actual amount, the regeneration process is executed even if the regeneration process is not actually required, and the fuel consumption is deteriorated. The possibility of the oil falling to the point where the oil is diluted and the oil is diluted.

  In the exhaust gas purifying apparatus 50 for an internal combustion engine according to the first embodiment of the present invention described above, the regeneration processing interval of the diesel particulate filter 23 is calculated based on the travel distance, but the filter regeneration processing interval (predetermined parameter value) is calculated. ), Instead of the travel distance, it may be calculated from a differential pressure before and after the diesel particulate filter, or a deposition amount based on the rotational speed of the internal combustion engine. Even such an exhaust gas purifying apparatus for an internal combustion engine has the same effects as the exhaust gas purifying apparatus 50 for an internal combustion engine according to the first embodiment of the present invention described above.

  In the above control, the diesel particulate filter 23 is heated by post-injection, and the exhaust gas purification device 50 of the internal combustion engine that performs forced regeneration to burn and remove soot has been described. However, a heater is added to the diesel particulate filter. It is good also as an exhaust-gas purification apparatus of the internal combustion engine which forcibly regenerates a diesel particulate filter by heating a heater. Even such an exhaust gas purifying apparatus for an internal combustion engine has the same effects as the exhaust gas purifying apparatus 50 for an internal combustion engine according to the first embodiment of the present invention described above.

Hereinafter, an exhaust gas purification apparatus for an internal combustion engine according to a second embodiment of the present invention will be described with reference to the drawings. The exhaust gas purification apparatus for an internal combustion engine according to the present embodiment is a modification of only the post injection timing control in the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention described above, and relates to the apparatus configuration. Description is omitted.
FIG. 5 is a flowchart showing filter regeneration control executed by the exhaust gas purification apparatus for an internal combustion engine according to the second embodiment of the present invention.

  In the exhaust gas purification apparatus for an internal combustion engine according to the second embodiment of the present invention, the ECU 31 performs forced regeneration control of the diesel particulate filter 23 based on the flowchart shown in FIG. First, in step S21, it is determined whether the travel distance calculated from the vehicle speed detected by the vehicle speed sensor 30 is greater than the regeneration start distance (first determination value). That is, the amount of soot collected by the diesel particulate filter 23 is calculated from the travel distance and estimated. If the travel distance is equal to or smaller than the regeneration start distance, the process proceeds to step S22, and if the travel distance is greater than the regeneration start distance, the process proceeds to step S23.

  In step S22, it is determined whether the soot accumulation amount is larger than the regeneration start accumulation amount (second determination value). That is, the amount of soot collected by the diesel particulate filter 23 is calculated from the differential pressure before and after the filter 23 detected by the DPF differential pressure sensor 27 or the rotational speed of the internal combustion engine detected by the crank angle sensor 28. Has been estimated. If the soot accumulation amount is larger than the regeneration start accumulation amount in step S22, the process proceeds to step S23, while if the soot accumulation amount is the same as or smaller than the regeneration start accumulation amount, the process is terminated. Become.

  Subsequently, regeneration control of the diesel particulate filter 23 is performed in step S23. That is, in order to forcibly regenerate the diesel particulate filter 23, the soot collected by the diesel particulate filter 23 by the post injection is burned and removed.

  Then, it progresses to step S24. In this step, the maximum temperature during the filter regeneration process is measured by the third temperature sensor 26.

  Then, it progresses to step S25. In this step, the end of regeneration control of the diesel particulate filter 23 is determined. That is, before the predetermined time has elapsed since the start of the regeneration control of the diesel particulate filter 23, the process returns to step S23, and after the predetermined time has elapsed since the start of the regeneration control of the diesel particulate filter 23, the regeneration process is performed. Assuming the completion, the regeneration control (post injection) of the diesel particulate filter 23 is terminated, and the process proceeds to step S26.

  In step S26, a start condition for regeneration control of the diesel particulate filter 23 is determined. That is, if the regeneration control start condition is the travel distance, the process proceeds to step S27. If the regeneration start condition is the soot accumulation amount, the process proceeds to step S28.

  In step S27, the regeneration start distance of the next diesel particulate filter 23 is calculated, and the process ends. That is, the next diesel particulate calculated from the difference between the maximum temperature during the diesel particulate filter regeneration process this time and the reference maximum temperature (predetermined reference maximum temperature) Tf when a predetermined amount of soot burns. The next regeneration start distance of the diesel particulate filter 23 is calculated from the correction amount of the regeneration start distance of the filter 23 and the previous regeneration start distance of the diesel particulate filter 23, and the process ends. The specific calculation formula is the same as the calculation formula (1) used in the exhaust gas purification apparatus 50 for an internal combustion engine according to the first embodiment of the present invention described above.

  In step S28, the next regeneration start accumulation amount of the diesel particulate filter 23 is calculated, and the process ends. That is, the correction amount of the next regeneration start accumulation amount of the diesel particulate filter 23 calculated from the difference between the maximum temperature at the time of regeneration processing of the diesel particulate filter 23 and the reference maximum temperature Tf described above, The regeneration start accumulation amount of the next diesel particulate filter 23 is calculated from the regeneration start accumulation amount of the diesel particulate filter 23, and the process ends. The specific calculation formula is the same as the calculation formula (1) used in the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention described above.

  Therefore, in the exhaust gas purification apparatus for an internal combustion engine that operates in such a flow, the regeneration processing interval of the diesel particulate filter 23 is corrected by the travel distance or the amount of soot accumulated.

  Therefore, according to the exhaust gas purification apparatus for an internal combustion engine according to the second embodiment of the present invention, the same effect as the exhaust gas purification apparatus for an internal combustion engine according to the first embodiment of the present invention described above can be obtained. The regeneration processing interval of the particulate filter 23 can be corrected by the travel distance or the amount of soot accumulation, and the regeneration processing interval of the diesel particulate filter 23 can be adjusted more accurately.

1 is a schematic configuration diagram of an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention. It is a flowchart which shows the regeneration control of the filter performed with the exhaust gas purification apparatus of the internal combustion engine which concerns on 1st Example of this invention. It is a graph which shows the regeneration process space | interval of the filter which the exhaust gas purification apparatus of the internal combustion engine which concerns on 1st Example of this invention has. It is a graph which shows the relationship between the highest temperature at the time of regeneration control in the filter which the exhaust gas purification apparatus of the internal combustion engine which concerns on 1st Example of this invention has, and the accumulation amount of soot. It is a flowchart which shows the regeneration control of the filter performed with the exhaust gas purification apparatus of the internal combustion engine which concerns on 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 3 Fuel injection nozzle 4 Combustion chamber 6 Common rail 10 Intake port 12 Exhaust port 13 Exhaust pipe 14 Intake valve 15 Exhaust valve 20 Exhaust gas purification apparatus main body 21 1st oxidation catalyst 22 2nd oxidation catalyst 23 Diesel particulate Filter 24 First temperature sensor 25 Second temperature sensor 26 Third temperature sensor 27 DPF differential pressure sensor 28 Crank angle sensor 29 Accelerator position sensor 30 Vehicle speed sensor 31 Electronic control unit (ECU)
50 Exhaust gas purification device for internal combustion engine

Claims (4)

A filter that collects particulates in the exhaust gas;
Filter regeneration means for regenerating the filter by determining when to regenerate the filter based on a predetermined parameter value;
Filter temperature detection means for detecting the temperature of the filter during regeneration processing by the filter regeneration means;
Correction means for correcting the determination value for the next regeneration processing time determination based on the maximum temperature of the filter detected by the filter temperature detection means;
An exhaust gas purifying apparatus for an internal combustion engine, comprising:   2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein the correction unit determines a correction amount of the determination value according to a difference between the maximum temperature and a predetermined reference maximum temperature.   When the maximum temperature is higher than the reference maximum temperature, the correction unit corrects the determination value so that the regeneration processing interval of the filter is shortened, and the maximum temperature is lower than the reference maximum temperature. 3. The exhaust gas purifying apparatus for an internal combustion engine according to claim 2, wherein the determination value is corrected so that the regeneration processing interval becomes longer.   The filter regeneration means uses the determination value with the predetermined parameter value as at least one of a travel distance of a vehicle on which the internal combustion engine is mounted, a differential pressure before and after the filter, and a rotational speed and a load of the internal combustion engine. The exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 3, wherein the exhaust gas purification device is set.

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