JP4811024B2 - Exhaust gas purification filter regeneration start timing control device and regeneration start timing control method - Google Patents

Description

  The present invention relates to an apparatus and method for controlling the start timing of regeneration control of an exhaust gas purification filter that captures particulates contained in exhaust gas discharged from an engine and prevents emission to the atmosphere.

Conventionally, a diesel engine has been fitted with a diesel particulate filter (Diesel Particulate Filter; hereinafter referred to as “DPF”) that captures particulate matter (hereinafter referred to as “PM”) in the exhaust passage as a measure for purifying exhaust gas. Yes. If the DPF continues to capture PM, it will eventually become clogged. Therefore, if PM accumulates to some extent, the exhaust gas temperature is raised and the temperature of the DPF (BED temperature) is increased to forcibly remove the deposited PM to regenerate the DPF (for example, Patent Document 1).
JP 2002-97930 A

  However, it has been found by the inventors' research that the regeneration timing may be too early in the conventional method described above due to the influence of non-combustible components deposited on the DPF. If the number of times of regeneration control of the DPF is large, the fuel efficiency is deteriorated and the engine oil is diluted with fuel. Therefore, it is desirable to reduce the number of regenerations with a control interval as much as possible in the regeneration control of the DPF.

  The present invention has been made paying attention to such a conventional problem, and a regeneration start timing control device and regeneration start timing control of an exhaust gas purification filter capable of preventing deterioration in fuel consumption during regeneration of the exhaust gas purification filter. It aims to provide a method.

The present invention is an exhaust gas purifying filter for preventing the discharge of captures particulates exhausted or engine et al to the atmosphere contained in the exhaust gas of the engine, incombustible components deposited on the exhaust gas purifying filter and incombustible component state detection means to detect the state of deposition, on the basis of the state where the incombustible component is accumulated in the exhaust gas purifying filter, the filter regeneration timing control means to control the regeneration start timing of the exhaust gas purifying filter And the incombustible component state detection means detects the accumulation state of the incombustible component deposited on the exhaust gas purification filter based on a regeneration history of whether the exhaust gas purification filter has been forcibly regenerated or spontaneously regenerated. And

  As the mileage of the vehicle increases, incombustible components accumulate on the exhaust gas purification filter. The inventors have found that the regeneration time of the DPF can be delayed by using this incombustible component. Therefore, in the present invention, the regeneration start timing of the exhaust gas purification filter is controlled based on the state in which the incombustible component is accumulated on the exhaust gas purification filter, so that the regeneration control can be started at an appropriate time, and the fuel efficiency is improved. It can suppress deterioration and dilution of engine oil due to fuel post injection during filter regeneration.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. First, in order to facilitate understanding of the present invention, the inventors' knowledge will be described with reference to FIGS.

  As described above, when PM accumulates in the DPF and the accumulated amount exceeds the reference amount, the exhaust gas temperature is raised to raise the DPF temperature (BED temperature), thereby forcibly removing the accumulated PM. And regenerating the DPF.

  Here, a threshold value (reference amount) for starting DPF regeneration control will be described with reference to FIG. FIG. 1 plots the relationship between the BPF temperature of the DPF and the maximum DPF temperature that can be reached from the BED temperature for each PM deposition amount when the DPF is new (that is, when Ash is not deposited). It is a figure which shows a graph. The maximum DPF temperature that can be reached is determined as follows. That is, when the engine in normal operation is suddenly idled, the amount of exhaust gas flowing through the DPF decreases rapidly, the air cooling effect due to the exhaust gas flow decreases, and the temperature inside the DPF increases rapidly. In this way, the inventors have confirmed that the temperature reached when the engine is suddenly changed from normal operation to idle operation is the highest DPF temperature that can be reached. Therefore, this temperature is set as the maximum DPF temperature that can be reached.

  According to FIG. 1, for example, when the amount of accumulated PM in the DPF is 2 g, the maximum DPF temperature is too high even if the engine is suddenly idled from the normal operation if the BED temperature of the DPF is low (eg, T1 ° C.). Don't be. However, when the BED temperature of the DPF is high to some extent (eg, T2 ° C.), the maximum temperature of the DPF rises due to PM combustion when the engine is suddenly changed from the normal operation to the idle operation.

  Even if the BED temperature of the DPF is the same (eg, T1 ° C.), the maximum DPF temperature will not be very high if the PM deposition amount is small (the maximum DPF temperature is T 2 g ° C. when the PM deposition amount is 2 g), but the PM deposition amount is large. Then, it can be seen that the PM burns and the maximum DPF temperature becomes high (when the PM deposition amount is 6 g, the maximum DPF temperature is T6 g ° C.).

  If the maximum DPF temperature is high, the DPF may be melted. Therefore, the maximum DPF temperature must be made lower than the DPF melting temperature. When the DPF is regenerated, the fuel is post-injected as described later and unburnt fuel is supplied to the oxidation catalyst to raise the exhaust gas temperature. Therefore, if the regeneration control of the DPF is frequently performed, the fuel efficiency is deteriorated and the engine oil is diluted with the fuel. Therefore, in the regeneration control of the DPF, it is possible to improve the fuel efficiency by reducing the number of regenerations with a control interval as much as possible, and it is possible to prevent the engine oil from being diluted with the fuel. Therefore, it is desirable that the regeneration interval be maintained until the amount of PM deposited is as large as possible so that the DPF does not melt even if the engine operating state changes and the temperature of the DPF rapidly increases. Based on this idea, the reference PM accumulation amount for starting DPF regeneration is set. That is, the upper limit value of the maximum DPF temperature is determined by the specification of the DPF. There is also a range in the DPFBED temperature that can be controlled when performing regeneration control of the DPF. Therefore, the threshold value for starting the DPF regeneration control is determined from the maximum DPF temperature and the DPFBED temperature. For example, in the DPF having the characteristics as shown in FIG. 1, when the PM accumulation amount reaches 6 g, the fuel injection amount and the injection timing are controlled to control the PM. Forced combustion control (DPF regeneration control) is performed.

  However, the present inventors have found that the maximum temperature of the DPF does not reach the DPF melting temperature even if more PM is deposited on the DPF depending on the operating state. The inventors' diligent research has revealed that this is due to impurities caused by additives in engine oil and the influence of Ash (ash), which is an incombustible component such as metal powder resulting from mechanical wear. That is, it has been found that the accumulation of Ash slows down the PM combustion rate in the DPF, and as shown in FIG. 2, the maximum temperature of the DPF at a certain PM accumulation amount decreases. Furthermore, it was found that the PM burning rate also depends on the deposition state of Ash. This point will be described in detail with reference to FIGS. FIG. 3 is a schematic diagram for explaining the action of the DPF in the normal operation of the diesel engine. FIG. 3 (A) shows a state where PM is captured, and FIG. 3 (B) shows Ash after forcibly burning PM. The deposition state of is shown. FIG. 4 is a schematic diagram showing the accumulation state of Ash in the DPF when the diesel engine is traveling at high speed. 3 and 4, PM is indicated by a white circle, and Ash is indicated by a black circle.

  The DPF has a porous honeycomb structure made of ceramic such as cordierite. In the DPF, flow paths are partitioned in a lattice shape by a porous thin wall. As shown in FIG. 3A, the inlets of the respective channels are alternately sealed. In the flow path where the inlet is not sealed, the outlet is sealed.

  As shown by the arrows in the figure, the exhaust gas flowing into the DPF permeates through the porous thin walls that define the flow paths and is discharged downstream. During normal operation, as shown in FIG. 3A, PM contained in the exhaust gas is trapped and deposited on the inner surface of the porous thin wall. Although a part of the trapped PM burns in the DPF, if the DPF temperature (BED temperature) is not high, the combustion amount is small and the deposition amount is larger than the PM combustion amount. If this state continues and the DPF continues to capture PM, it will eventually become clogged. Therefore, when the PM is accumulated to some extent, the exhaust gas temperature is raised and the accumulated PM is forcibly removed by combustion.

  However, Ash does not burn even if the PM deposited by raising the exhaust gas temperature is burned. As shown in FIG. 3B, this Ash is deposited on the downstream portion (bottom portion) of the DPF.

  On the other hand, during high-speed traveling, the exhaust gas temperature is high, and the DPF temperature (BED temperature) is also high. In this state, when PM contained in the exhaust gas is trapped on the inner surface of the DPF porous thin wall, it spontaneously burns without accumulating. However, Ash does not burn. Therefore, Ash is deposited on the inner surface of the porous thin wall as shown in FIG.

  As described above, the present inventors have different Ash accumulation states between the case where the PM deposited on the DPF is forcibly burned and the case where the PM naturally burns due to the exhaust gas temperature becoming high due to high-speed traveling or the like. Was discovered. Further, the inventors have found that, even if the amount of Ash deposition is the same, if the accumulation state of Ash is different, the PM combustion rate in the DPF is different and the maximum DPF temperature is different. Therefore, in the present invention, the regeneration timing may be early if the PM forced combustion control (DPF regeneration control) is always started with a uniform PM deposition amount even though the accumulation state of Ash is different. They found out.

  As described above, according to the inventors, it has been found that when the amount of deposited Ash increases, the PM combustion rate is slowed even if the amount of deposited PM is constant, and the maximum DPF temperature is lowered. Furthermore, it was found that the PM burning rate in the DPF also depends on the accumulation state of Ash. Therefore, in the present invention, the reference PM accumulation amount for starting the PM forced combustion control (DPF regeneration control) is corrected according to the accumulation amount and accumulation state of Ash so as to optimize the regeneration start timing.

  Hereinafter, a specific configuration will be described. FIG. 5 is an overall system diagram showing an embodiment of an exhaust gas purification filter regeneration start timing control apparatus according to the present invention.

  The exhaust gas purification filter regeneration start timing control device 1 includes a diesel engine 10, an intake passage 21, a throttle valve 22, an exhaust passage 23, and an exhaust gas recirculation (hereinafter referred to as “EGR device”) 30. , A diesel oxidation catalyst (Diesel Oxidation Catalyst; hereinafter referred to as “DOC”) 40, a DPF assembly 50, sensors 61 to 64, and a controller 70.

  The diesel engine 10 is injected with fuel, which has been increased in pressure by the high-pressure pump 14 and once accumulated in the common rail 13, from the injector 12 in accordance with the injection timing.

  Part of the exhaust gas discharged from the diesel engine 10 returns to the intake passage 21 via the EGR device 30. The EGR device 30 includes an EGR cooler 32 and an EGR valve 33 in the EGR passage 31. The EGR cooler 32 cools the exhaust gas recirculated from the exhaust passage 23. The EGR valve 33 is opened and closed to adjust the EGR amount. The EGR valve 33 is duty-controlled by the controller 70.

  The DOC 40 is provided in the exhaust passage 23 of the diesel engine 10 and reduces particulate matter by an oxidizing action by a catalyst such as palladium or platinum. When an unburned component (hydrocarbon HC) flows into the DOC 40, exhaust gas that has become a high temperature due to the catalytic reaction flows out of the DOC 40.

  The DPF assembly 50 is provided further downstream of the DOC 40. The DPF assembly 50 incorporates a DPF 52 in a DPF housing 51. The DPF 52 has a porous honeycomb structure made of ceramic such as cordierite. In the DPF 52, flow paths are partitioned in a lattice shape by porous thin walls. The inlets of the respective channels are alternately sealed. In the flow path where the inlet is not sealed, the outlet is sealed. The exhaust gas that has flowed into the DPF 52 passes through the porous thin wall that partitions each flow path and is discharged downstream. PM contained in the exhaust gas is trapped and deposited on the inner surface of the porous thin wall. Although a part of the trapped PM burns in the DPF, if the DPF temperature (BED temperature) is not high, the combustion amount is small and the deposition amount is larger than the PM combustion amount. If this state continues and the DPF continues to capture PM, it will eventually become clogged. Therefore, when the PM is accumulated to some extent, the exhaust gas temperature is raised and the accumulated PM is forcibly removed by combustion.

  The differential pressure sensor 61 detects the differential pressure in the upstream chamber 51 a (inlet of the DPF 52) and the downstream chamber 51 b (exit of the DPF 52) of the DPF housing 51, and outputs a differential pressure signal to the controller 70.

  The DPF inlet temperature sensor 62 detects the inlet temperature Tin of the DPF 52 and outputs an inlet temperature signal to the controller 70.

  The DPF outlet temperature sensor 63 detects the outlet temperature Tout of the DPF 52 and outputs an outlet temperature signal to the controller 70.

  The crank angle sensor 64 detects the rotational speed of the crankshaft 11 of the diesel engine 10.

  The controller 70 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).

  The controller 70 detects the PM discharge amount PMout based on the PM discharge amount map for each engine operating state (for example, the rotation speed and the fuel injection amount). Based on this PM discharge amount PMout, the PM deposition amount PMa is estimated. Details of this estimation method will be described later. Then, the controller 70 determines the DPF regeneration timing based on this PM accumulation amount PMa. The controller 70 also receives a differential pressure signal from the differential pressure sensor 61. The controller 70 inputs the inlet temperature signal of the DPF inlet temperature sensor 62 and the outlet temperature signal of the DPF outlet temperature sensor 63, and calculates the BED temperature of the DPF 52 based on these. The controller 70 determines the optimum gear position (gear ratio) from the operating state of the engine, and calculates the travel distance together with the signal of the crank angle sensor 64.

  The controller 70 controls the injector 12 and the high-pressure pump 14 based on the input signal to adjust the fuel injection amount and the injection timing. The controller 70 adjusts the opening degree of the throttle valve 22 based on the input signal. The controller 70 performs duty control on the EGR valve 33. The controller 70 controls these to adjust the excess air ratio (air-fuel ratio) (λ control) to adjust the unburned components (hydrocarbon HC) contained in the exhaust gas, and increase the exhaust gas temperature flowing out from the DOC 40 The DPF is regenerated by increasing the BED temperature of the DPF.

  Next, a specific operation of the exhaust gas purification filter regeneration start timing control apparatus according to the present invention will be described focusing on the operation of the controller 70. FIG. 6 is a main flowchart for explaining the operation of the regeneration start timing control device for the exhaust gas purification filter. The controller 70 repeatedly executes this process every minute time (for example, 10 milliseconds).

  In step S1, the controller 70 estimates the PM accumulation amount PMa. A specific estimation method will be described later.

  In step S2, the controller 70 calculates a reference PM deposition amount correction value PMHOS. A specific calculation method will be described later.

  In step S3, the controller 70 calculates the corrected reference PM deposition amount PM1 by adding the reference PM deposition amount correction value PMHOS to the reference PM deposition amount basic value PM0. The reference PM accumulation amount basic value PM0 is a threshold value for starting DPF regeneration control in order to make the maximum DPF temperature below the DPF melting temperature when the DPF is new (that is, when Ash is not accumulated). For example, if the DPF has the characteristics shown in FIG.

  In step S4, the controller 70 determines whether or not the corrected reference PM deposition amount PM1 exceeds the PM deposition amount limit value PMlimit. If not, the process proceeds to step S5. Otherwise, the process proceeds to step S6. The PM accumulation amount limit value PMlimit is the maximum PM amount that can be captured by the DPF 52, and is set in advance. This PM deposition amount limit value PMlimit corresponds to the “realizable threshold” in the claims.

  In step S5, the controller 70 sets the corrected reference PM deposition amount PM1 as the PM deposition amount threshold PMc which is a threshold for starting the DPF regeneration control.

  In step S7, the controller 70 sets the PM accumulation amount limit value PMlimit as the PM accumulation amount threshold value PMc that is a threshold value for starting the DPF regeneration control.

  FIG. 7 is a flowchart of a subroutine showing the PM accumulation amount estimation process.

  In step S11, the controller 70 detects the PM emission amount PMout based on the PM emission amount map for each engine operating state (for example, the rotation speed and the fuel injection amount). This map is set in advance through experiments.

  In step S12, the controller 70 obtains the PM combustion amount PMburn by applying the BED temperature of the DPF and the PM deposition amount PMa (previous) detected last time to the characteristic map shown in FIG. This map is set in advance through experiments.

  In step S13, the controller 70 calculates the PM accumulation amount PMa by the following equation.

  FIG. 8 is a flowchart of a subroutine showing a process for obtaining the reference PM accumulation amount correction value PMHOS.

  In step S21, the controller 70 determines whether or not the inlet temperature Tin of the DPF 52 exceeds the reference temperature. The higher the inlet temperature of the DPF 52 (that is, the exhaust gas temperature flowing into the DPF), the easier it is for the PM to spontaneously burn within the DPF 52. The reference inlet temperature determines this. The reference inlet temperature is set in advance through experiments and is, for example, 450 ° C. If the inlet temperature Tin of the DPF 52 exceeds the reference temperature, the process proceeds to step S22, and if not, the process proceeds to step S24.

  In step S22, the controller 70 determines whether or not the BED temperature Tbed of the DPF 52 exceeds the reference BED temperature. The higher the BED temperature of the DPF 52 (that is, the internal temperature of the DPF), the easier it is for the PM to spontaneously combust within the DPF 52. The reference BED temperature determines this. The reference BED temperature is set in advance through experiments, and is, for example, 600 ° C. If the BED temperature Tbed of the DPF 52 exceeds the reference temperature, the process proceeds to step S23, and if not, the process proceeds to step S24.

  In step S23, the controller 70 determines whether or not the PM accumulation amount PMa of the DPF 52 exceeds the reference accumulation amount. The more PM is deposited in the DPF 52, the more difficult it is for the PM to spontaneously burn in the DPF 52. The reference deposition amount determines this. The reference accumulation amount is set through experiments in advance, and is 0 gram, for example. If the PM deposition amount PMa of the DPF 52 exceeds the reference deposition amount, the process proceeds to step S24, and if not, the process proceeds to step S25.

  In step S24, the controller 70 executes a bottom deposition process. Details will be described later.

  In step S25, the controller 70 executes wall surface deposition processing. Details will be described later.

  In step S26, the controller 70 obtains the reference PM accumulation amount correction value PMHOS by the following equation.

  FIG. 9 is a flowchart of a subroutine showing the bottom accumulation process.

  In step S241, the controller 70 calculates a travel distance based on the engine rotation speed signal and the gear position signal.

  In step S242, the controller 70 determines whether or not the previous time was the wall surface deposition mode. If the previous time was the wall surface accumulation mode, the process proceeds to step S243, and if not the wall surface accumulation mode, the process is temporarily exited.

  In step S243, the controller 70 obtains the amount of Ash (Ash0) flowing into the DPF 52 by applying the travel distance to the characteristic map shown in FIG. This map is set in advance through experiments.

  In step S244, the controller 70 obtains the bottom accumulated Ash amount Ash1 by the following equation. The bottom accumulated Ash amount Ash1 corresponds to the “first integrated value” in the claims.

  In Step S245, the controller 70 obtains the bottom Ash influence correction value HOS1 by applying the bottom accumulation Ash amount Ash1 to the characteristic map shown in FIG. 13A stored in advance in the ROM. This bottom Ash influence correction value HOS1 corresponds to the “first correction value” in the claims.

  In step S246, the controller 70 resets the travel distance, and in step S247, changes the previous mode MODEz to 1.

  FIG. 10 is a flowchart of a subroutine showing the wall surface deposition process.

  In step S251, the controller 70 calculates a travel distance based on the engine rotation speed signal and the gear position signal.

  In step S252, the controller 70 determines whether or not the previous time was the bottom deposition mode. If the previous time was the bottom accumulation mode, the process proceeds to step S253, and if not the bottom accumulation mode, the process is temporarily exited.

  In step S253, the controller 70 obtains the Ash amount (Ash0) flowing into the DPF 52 by applying the travel distance to the characteristic map shown in FIG. This map is set in advance through experiments.

  In step S254, the controller 70 obtains the wall surface deposition Ash amount Ash2 by the following equation. The wall surface deposition Ash amount Ash2 corresponds to the “second integrated value” in the claims.

  In Step S255, the controller 70 obtains the wall surface Ash influence correction value HOS2 by applying the wall surface deposition Ash amount Ash2 to the characteristic map shown in FIG. The wall surface Ash influence correction value HOS2 corresponds to a “second correction value” in the claims.

  In step S256, the controller 70 resets the travel distance, and in step S257, changes the previous mode MODEz to 2.

  As described above in detail, according to the inventors, it has been found that when the deposit amount of Ash increases, the PM combustion rate becomes slow and the maximum DPF temperature decreases even if the PM deposit amount is constant. Furthermore, it was found that the PM burning rate in the DPF also depends on the accumulation state of Ash. Therefore, in the present invention, by correcting the reference PM accumulation amount for starting PM forced combustion control (DPF regeneration control) according to the accumulation amount and accumulation state of Ash, the regeneration interval is extended as Ash accumulates, It was designed to optimize the regeneration time. For this reason, deterioration of fuel consumption and dilution of engine oil due to fuel post injection during DPF regeneration can be suppressed.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

  For example, the BED temperature of the DPF may be detected by attaching a sensor to the DPF. Each map is only an example, and may be appropriately selected by experiment.

  Moreover, in the said embodiment, although the diesel engine was mentioned as an example and demonstrated as an engine, a gasoline engine may be sufficient.

The figure which shows the graph which plotted the relationship between the BED temperature of DPF and the highest DPF temperature which can be reached | attained from the BED temperature for every PM deposition amount when DPF is a new article (namely, when Ash is not deposited). It is. It is a figure which shows a mode that PM combustion speed in DPF becomes slow by accumulation of Ash. It is a schematic diagram explaining the effect | action of DPF in the normal driving | operation of a diesel engine. It is a schematic diagram which shows the accumulation state of Ash of DPF in the high-speed driving | running | working of a diesel engine. 1 is an overall system diagram showing an embodiment of a regeneration start timing control device for an exhaust gas purification filter according to the present invention. It is a main flowchart explaining operation | movement of the regeneration start time control apparatus of an exhaust gas purification filter. It is a flowchart which shows the subroutine of PM accumulation amount estimation processing. It is a flowchart which shows the subroutine of the process which calculates | requires reference | standard PM deposition amount correction value PMHOS. It is a flowchart which shows the subroutine of a bottom part deposition process. It is a flowchart which shows the subroutine of a wall surface deposition process. It is a characteristic map of PM combustion amount. It is a characteristic map of the amount of Ash flowing into DPF. It is a characteristic map of Ash influence correction value.

Explanation of symbols

1 Exhaust gas purification filter regeneration start timing control device 10 Diesel engine 50 DPF assembly 52 DPF (diesel particulate filter; exhaust gas purification filter)
61 Differential Pressure Sensor 62 DPF Inlet Temperature Sensor 63 DPF Outlet Temperature Sensor 70 Controller Steps S7 to S8 Filter regeneration timing control means / filter regeneration timing control step Steps S24 and S25 Nonflammable component state detection means / Nonflammable component state detection step

Claims (10)

An exhaust gas purification filter that captures particulates discharged from the engine and prevents emission to the atmosphere;
Incombustible component state detection means for detecting the accumulation state of the incombustible component contained in the exhaust gas of the engine and deposited on the exhaust gas purification filter;
Filter regeneration timing control means for controlling the regeneration start timing of the exhaust gas purification filter based on the state where the incombustible component is deposited on the exhaust gas purification filter;
With
The incombustible component state detection means detects the accumulation state of the incombustible component deposited on the exhaust gas purification filter based on the regeneration history of whether the exhaust gas purification filter has been forcibly regenerated or naturally regenerated.
An apparatus for controlling the start of regeneration of an exhaust gas purification filter. The incombustible component is Ash discharged from the engine.
The regeneration start timing control device for an exhaust gas purification filter according to claim 1. The filter regeneration timing control means delays the regeneration start timing of the exhaust gas purification filter as the incombustible component increases.
The regeneration start timing control device for an exhaust gas purification filter according to claim 1 or 2. The filter regeneration timing control means sets a filter regeneration start threshold based on the state of incombustible components accumulated on the exhaust gas purification filter, and exhaust gas purification is performed when the particulate amount captured by the exhaust gas purification filter exceeds the filter regeneration start threshold. Start filter regeneration control,
The regeneration start timing control device for an exhaust gas purification filter according to any one of claims 1 to 3, characterized in that: An exhaust gas purification filter that captures particulates discharged from the engine and prevents emission to the atmosphere;
Incombustible component state detection means for detecting the accumulation state of the incombustible component contained in the exhaust gas of the engine and deposited on the exhaust gas purification filter;
Filter regeneration timing control means for controlling the regeneration start timing of the exhaust gas purification filter based on the state where the incombustible component is deposited on the exhaust gas purification filter;
With
The incombustible component state detection means detects the accumulation of the incombustible component on the bottom of the exhaust gas purification filter during forced regeneration of the exhaust gas purification filter, and the exhaust gas purification of the incombustible component during natural regeneration of the exhaust gas purification filter. Detects filter accumulation on the wall,
The filter regeneration timing control means sets a filter regeneration start threshold based on the incombustible component accumulation amount deposited on the bottom of the exhaust gas purification filter and the incombustible component accumulation amount accumulated on the wall surface of the exhaust gas purification filter, and the exhaust gas purification filter Starts the regeneration control of the exhaust gas purification filter when the amount of particulates captured by the filter exceeds the filter regeneration start threshold.
Regeneration start timing control device of the exhaust gas purifying filter you wherein a. Before SL filter regeneration timing control means, based on the second correction value calculated in the first correction value calculated from the incombustible component bottom deposition amount of the exhaust gas purifying filter, the incombustible component wall deposit quantity of the exhaust gas purifying filter, the filter Set playback start threshold,
The regeneration start timing control device for an exhaust gas purification filter according to claim 5. The first correction value is larger as the non-combustible component bottom accumulation amount of the exhaust gas purification filter is larger.
The regeneration start timing control device for an exhaust gas purification filter according to claim 6. The second correction value is larger as the amount of non-combustible component wall surface accumulation of the exhaust gas purification filter is larger.
The regeneration start timing control device for an exhaust gas purification filter according to claim 6 . When the filter regeneration start threshold set based on the first correction value and the second correction value exceeds a feasible threshold, the filter regeneration timing control means sets the feasible threshold as the filter regeneration start threshold. Set to
The exhaust gas purification filter regeneration start timing control device according to any one of claims 6 to 8, wherein A non-combustible component state detection step for detecting the accumulation state of the exhaust gas incombustible component deposited on the exhaust gas purification filter that captures particulates discharged from the engine and prevents emission to the atmosphere;
A filter regeneration timing control step for controlling the regeneration start timing of the exhaust gas purification filter based on the state where the incombustible component is deposited on the exhaust gas purification filter;
With
The incombustible component state detection step detects the accumulation state of the incombustible component deposited on the exhaust gas purification filter based on the regeneration history of whether the exhaust gas purification filter has been forcibly regenerated or naturally regenerated.
Reproduction start timing control method for an exhaust gas purifying filter you wherein a.

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