JP2002250218A - Continuously regenerating diesel particulate filter and regeneration control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuously regenerating diesel particulate filter and a regeneration control method therefor, in whish clogging of the filter is surely prevented, by controlling an engine exhaust temperature while monitoring a depositing state of PM. SOLUTION: The continuously regenerating diesel particulate filter 1 comprises; a filter 4 with catalyst that filters particulate matters in exhaust gas G of a diesel engine E, and burns and removing the particulate matters by catalysis; and an oxidation catalyst 3 disposed upstream of the filter 4 with catalyst. A regeneration control means 50 is constituted so that fuel injection control of the engine E makes the exhaust gas temperature increase to burn the particulate matters, when regenerating the filter 4 with catalyst under an engine operating state where the exhaust gas temperature of the engine E is lower than a temperature to start burning of the particulate matters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously regenerating type diesel particulate filter device for collecting particulate matter of a diesel engine and purifying exhaust gas, and a regeneration control method therefor.

[0002]

2. Description of the Related Art Regulations on the amount of particulate matter (PM) emitted from a diesel engine have been strengthened year by year along with NOx, CO, HC and the like. Diesel Particulate Filter (DPF)
: A technique called DPF) to reduce the amount of PM discharged to the outside.

[0003] DPFs for trapping PM include a monolith honeycomb type wall flow type filter made of ceramic, a fiber type filter type made of ceramic or metal in a fibrous form, and the like. The gas purifying device is installed in the middle of the exhaust pipe of the engine, like other exhaust gas purifying devices, and purifies and discharges exhaust gas generated by the engine.

[0004] However, the DPF for collecting PM is composed of PM.
Clogging progresses with the collection of PM, and the exhaust gas pressure (discharge pressure) increases in proportion to the amount of collected PM.
There is a need to remove PM from PF, and several methods and devices have been developed.

[0005] One of them is a continuous regeneration type DPF that reduces the combustion start temperature of PM by the action of a catalyst such as γ-alumina, Pt, or zeolite carried on a filter, and incinerates the PM by exhaust gas. Proposed.

In the case of this continuous regeneration type diesel particulate filter (DPF) device, the temperature of the exhaust gas flowing into the DPF may be raised to a temperature for activating the catalyst (for example, about 250 ° C. or higher). Will be.

[0007] The mechanism of purifying PM in the exhaust gas differs depending on the engine operating region (torque and engine speed) (C1) and (C2) as shown in FIG.

First, in the area (C1), (4CeO ₂ + C → 2CeO ₃ + C) due to the catalytic action of the catalyzed filter 4
Carbon (C: PM) is oxidized to carbon dioxide (CO ₂ ) by the reaction of O ₂ , 2CeO ₃ + O ₂ → 4CeO ₂ , and in the region (C ₂ ), carbon (C: PM) is reacted by the reaction of (C + O ₂ → CO ₂ ). : PM) is oxidized to carbon dioxide (CO ₂ ).

Then, as shown in FIG. 11, the operating range of the engine (torque and engine speed) (C1), (C2)
By purifying the PM collected by the catalyzed filter 4, the PM in the exhaust gas G is purified while continuously regenerating the catalyzed filter 4. It should be noted that although the classification of (C1) and (C2) is schematically shown in FIG. 11, there is not always a clear boundary line, and the main reaction gradually changes.

[0010]

However, in this continuous regeneration type DPF device, when the exhaust gas temperature corresponding to the operation region (D) of the engine shown in FIG. Since the activity is reduced, the above reaction does not occur, and PM cannot be oxidized to regenerate the filter. Therefore, there is a problem that the deposition of PM is continued and the filter is clogged.

In particular, during idling operation, low load operation, engine braking operation on downhill, etc., the fuel is hardly burned, and low-temperature exhaust gas flows into the filter with the catalyst. The catalytic activity decreases. Then, there is a problem that PM accumulates on the filter during the operation time when the filter cannot be regenerated, and the exhaust pressure increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. An object of the present invention is to control the exhaust gas temperature of an engine while monitoring the accumulation state of PM in a continuous regeneration type diesel particulate filter device. An object of the present invention is to provide a continuous regeneration type diesel particulate filter device capable of efficiently removing PM while reliably preventing clogging of a filter by controlling the same, and a control method thereof.

[0013]

Means for Solving the Problems [Continuous Regeneration Type DPF Apparatus] The continuous regeneration type particulate filter (DPF) apparatus for achieving the above object is constituted as follows.

1) A continuously regenerating diesel particulate filter device provided with a filter for collecting particulate matter in exhaust gas of a diesel engine and burning the collected particulate matter by a catalytic action. An oxidation catalyst for oxidizing HC and CO in the exhaust gas to raise the temperature of the exhaust gas is provided on the upstream side of the filter.

According to this configuration, carbon monoxide (CO) and unburned fuel (HC) in the exhaust gas are oxidized by the oxidation catalyst provided on the upstream side of the continuous regeneration type catalyst-equipped filter.
Since the temperature of the exhaust gas flowing into the catalyzed filter can be increased, the temperature of the catalyzed filter can be increased even in an engine operating state where the exhaust gas temperature is relatively low, and the particulate matter trapped can be increased. (PM) can be removed by burning.

In a low torque, low rotational speed engine operating state (A) in which the trapped particulate matter is not burned and removed in normal operation, when the filter with the catalyst is clogged, By performing a fuel injection control such as a delay operation (retard) of a main injection timing and a post-injection (post-injection), the temperature of the exhaust gas is raised to burn off PM.

2) The continuous regenerating type diesel particulate filter device described above, further comprising a regenerating control unit for performing a regenerating process for clogging of the filter with a catalyst, wherein the regenerating control unit is configured to control the exhaust gas temperature of the engine to the oxidization level. During regeneration of the catalyzed filter under engine operating conditions lower than the activation temperature of the catalyst, the exhaust gas temperature is increased by fuel injection control of the engine to activate the oxidation catalyst, and the particles collected by the catalyzed filter It is configured to burn off particulate matter.

According to this configuration, in the continuous regeneration type diesel particulate filter device in the prior art,
Even in low-torque, low-rotational-speed engine operating conditions where the exhaust gas temperature is low and the trapped particulate matter is not burned off, the main injection timing delay (retard) operation and post-injection (post-injection) By performing the fuel injection control, the temperature of the exhaust gas is increased, the oxidation catalyst is activated, and the temperature of the exhaust gas passing through the oxidation catalyst can be further increased.

As a result, the temperature of the filter with the catalyst rises, and the particulate matter trapped in the filter with the catalyst is burned and removed by the catalytic action of the filter with the catalyst. Even during a downhill traveling operation in which the engine brake is operated, the filter with the catalyst is not clogged and the particulate matter in the exhaust gas is continuously collected.

In addition, since the heating of the particulate matter is controlled by controlling the exhaust gas temperature in the delay operation of the main injection timing of the fuel injection or in the post-injection without using the heater. This fuel injection can be performed by the existing fuel injection control device, so that it is not necessary to add new equipment such as a heater for heating or a power supply or a new control device, and the entire device can be made compact. Therefore, the device can be easily attached to the vehicle.

3) In the continuous regeneration type diesel particulate filter device described above, the exhaust gas temperature is increased in two or more stages by the fuel injection control.

According to this configuration, the exhaust gas temperature is raised in two or more stages in multiple stages, so that the PM deposited on the catalyzed filter rapidly burns in a chain reaction to cause runaway combustion. Can be prevented from occurring, and it is possible to prevent the temperature of the filter with a catalyst from being higher than the melting temperature and being damaged.

4) In the continuous regenerative diesel particulate filter device described above, the fuel injection control is configured to include at least one of a main injection delay operation and a post-injection operation.

According to this configuration, as the fuel injection control,
Since the main injection delay operation and post-injection operation are adopted,
This can be dealt with only by changing the program of the existing fuel injection control device, and the filter regeneration can be performed relatively easily even in the low torque and low speed region of the engine.

[Regeneration Control Method] The regeneration control method of the continuous regeneration type diesel particulate filter device is configured as follows.

1) A filter with a catalyst for collecting particulate matter in the exhaust gas of a diesel engine and burning the collected particulate matter by a catalytic action, and an HC in the exhaust gas is provided upstream of the filter with the catalyst. And a continuous regeneration type diesel particulate filter device formed having an oxidation catalyst that oxidizes CO and raises the exhaust gas temperature.
During regeneration of the catalyzed filter under engine operating conditions in which the exhaust gas temperature of the engine is lower than the activation temperature of the oxidation catalyst, the fuel injection of the engine is performed in order to burn and remove the particulate matter collected by the catalyzed filter. It is configured as a method of raising the exhaust gas temperature by control.

According to the above-mentioned method, in the conventional regeneration control method of the continuous regeneration type diesel particulate filter device, the exhaust gas temperature is low, the activity of the oxidation catalyst is low, and the collected particulate matter is burned. In an operating state of an engine with a low torque and a low rotational speed that cannot be removed, the exhaust gas temperature rises by performing a fuel injection control such as a delay (retard) operation of the main injection timing and a post-injection (post-injection). Since the oxidation catalyst is activated and the trapped particulate matter is burned and removed by the catalytic action of the catalyzed filter, the engine can be operated during idling, at low speeds, or during downhill running such as when operating an engine brake. In this case, the catalyst-equipped filter continuously collects particulate matter in the exhaust gas without clogging. So as to.

2) In the regeneration control method for the continuous regeneration type diesel particulate filter device, the exhaust gas temperature is increased by the fuel injection control in two or more stages.

According to this method, the temperature of the exhaust gas is raised in two or more stages, so that the PM deposited on the catalyst-equipped filter burns rapidly in a chain reaction.
It is possible to avoid that the temperature of the filter with the catalyst becomes higher than the melting temperature and is damaged.

3) In the regeneration control method for the continuous regeneration type diesel particulate filter device described above, the fuel injection control is configured to include at least one of a main injection delay operation and a post-injection operation.

According to this method, since the delay operation of the timing of the main injection and the post-injection are employed as the fuel injection, it is possible to cope only by changing the program of the existing fuel injection control device. It is possible to easily regenerate the filter with the catalyst even in the low torque and low speed range of the engine.

4) In the regeneration control method for the continuous regeneration type diesel particulate filter device described above, at the time of the regeneration, the main injection of the fuel is first delayed to operate.
After the temperature of the exhaust gas is raised, and after the temperature of the exhaust gas flowing into the catalyst-equipped filter reaches a predetermined first target temperature value, a post-injection operation of fuel is performed to further raise the temperature of the exhaust gas. It is composed of

According to this method, at the start of the regeneration mode operation, the temperature of the exhaust gas is increased by delaying the timing of the main injection to preheat the oxidation catalyst, activate the oxidation catalyst, and then perform the post-injection. Since it is performed, it is possible to prevent the generation of white smoke which tends to occur at the start of the reproduction.

5) In the regeneration control method of the continuous regeneration type diesel particulate filter device described above, in the post-injection operation of the fuel, a post-injection of a specified amount of fuel is performed, and the temperature of the exhaust gas flowing into the filter with a catalyst is increased. After reaching a predetermined second target temperature value, the amount of post-injection of fuel is increased to further increase the exhaust gas temperature.

According to this method, the temperature of the exhaust gas entering the filter with the catalyst is increased in two or more stages, so that a sudden increase in the temperature due to chain rapid combustion of the deposited PM can be prevented. Thus, erosion of the catalyzed filter is avoided.

6) In the regeneration control method for the continuous regeneration type diesel particulate filter device, the amount of particulate matter accumulated in the filter with a catalyst and the amount of particulate matter burned and removed during operation of the engine are determined by the engine. Estimated from the operating state of the above, cumulative calculation is performed to calculate the accumulated amount of the particulate matter, and whether or not the estimated accumulated amount of the particulate matter exceeds a predetermined accumulated amount is used to determine the start of regeneration. It is configured as follows.

According to this method, while the accumulated state of the particulate matter is estimated and calculated, the regeneration mode is operated when the accumulated estimated value of the particulate matter exceeds a predetermined accumulation amount. Reproduction can be performed at an optimal timing.

Therefore, it is possible to efficiently collect, burn and remove particulate matter while preventing deterioration of fuel efficiency.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A continuous regeneration type diesel particulate filter device (hereinafter referred to as a continuous regeneration type DPF device) according to an embodiment of the present invention will be described below with reference to the drawings.

[Structure of Apparatus] FIG. 1 shows the structure of a continuous regeneration type DPF apparatus of this embodiment. This continuous reproduction type D
The PF device 1 is provided in the exhaust passage 2 of the engine E, and is provided with an oxidation catalyst 3 and a filter 4 with a catalyst from the upstream side.

A first exhaust pressure sensor 51 is provided on the exhaust inlet side of the oxidation catalyst 3 for controlling regeneration of the filter with catalyst 4.
A first temperature sensor 53 is provided between the oxidation catalyst 3 and the catalyzed filter 4, and a second temperature sensor 53 is provided on the exhaust outlet side of the catalyzed filter 4.
An exhaust pressure sensor 52 and a second temperature sensor 54 are provided.

The output values of these sensors are input to an engine control unit (ECU: engine control unit) 50 which controls the overall operation of the engine and also controls the regeneration of the filter 4 with a catalyst. 50
The fuel injection device 5 of the engine is controlled by the control signal output from the ECU.

The oxidation catalyst 3 is formed by supporting an oxidation catalyst such as platinum (Pt), γ-alumina, or zeolite on a support such as a porous ceramic honeycomb structure. Monolith honeycomb type wall flow type filter in which the inlet and outlet of the high quality ceramic honeycomb channel are alternately plugged, and a felt-like filter in which inorganic fibers such as alumina are randomly laminated are formed. Is formed by supporting a catalyst such as Pt, γ-alumina and zeolite.

Then, the filter of the filter with catalyst 4 is
When a monolith honeycomb type wall flow type filter is employed, the particulate matter in the exhaust gas G (hereinafter referred to as P
M) is collected by a porous ceramic wall (trap), and when a fiber type filter type is adopted,
The PM is collected by the inorganic fibers of the filter.

[Regeneration Control Method] Next, a regeneration control method in the continuous regeneration type DPF device 1 having the above configuration will be described.

This reproduction control method is performed according to the flow illustrated in FIGS.

For ease of explanation, these exemplified flows are shown as regeneration control flows which are repeatedly called and executed in parallel with the control flow of the engine E. In other words, during the operation control of the engine E, this flow is repeatedly called and executed at regular time intervals, and when the control of the engine E is completed, this flow is not called, and the regeneration control of the filter 4 with catalyst is substantially performed. It is configured to end.

[Outline of Regeneration Control Method] In the regeneration control flow of the present invention, the exhaust pressure Pe detected by the first exhaust pressure sensor 51 at the start of the regeneration mode operation is equal to a predetermined first exhaust pressure determination value Pe.
Not only when it exceeds the maximum, but also when the accumulated amount of PM in the catalyzed filter 4, that is, the PM accumulated estimated value PMs becomes a predetermined P
It is configured so that the determination is performed also when the value becomes equal to or more than the M determination value PMmax.

In the regeneration control flow illustrated in FIG. 2, first, in step S21, the PM accumulated estimated value PMs is equal to or larger than a predetermined PM determination value PMmax, or the exhaust pressure Pe is determined.
Is greater than or equal to a predetermined first exhaust pressure determination value Pemax, and if any, the process shifts to the regeneration mode operation of step S30, and if not, returns.

The flow of the regeneration mode operation in step S30 includes the steps of cutting EGR (exhaust gas recirculation) in step S31.
The first stage of temperature rise for preheating by delaying (retarding) the timing of the main injection (main) of the fuel injection in step S32, post-injection (post-injection) in step S33, injecting a specified amount of fuel, and burning PM. The second stage of the temperature rise to be started, the third stage of the temperature rise in which the PM injection is performed by increasing the injection amount of the post-injection in step S34, and the PM is cleaned by further increasing the injection amount of the post-injection in step S35. It is composed of a series of operations of the fourth stage of temperature rise and the end of the regeneration mode operation in step S36.

Hereinafter, each step will be described in detail.

[Estimation of Cumulative Value of PM] Step S in FIG.
21 used to determine the transition to the regeneration mode operation of PM 21
The calculation of the accumulated estimated value PMs will be described in detail. This PM accumulated estimation value PMs is performed according to a PM accumulated estimation flow as illustrated in FIG.

In the flow of estimating PM accumulation in FIG. 3, when this flow starts, first, in step S11,
The torque Q indicating the operating state of the engine E, the engine speed Ne, and the DPF inlet temperature T1 measured by the first temperature sensor 53 are input.

In the next step S12, the DPF inlet temperature Tb at the balance point (BP) is calculated from the previously input map data Mtb (Q, Ne) based on the torque Q and the engine speed Ne.

The balance point is defined as an area in which the exhaust gas temperature is low and the catalytic activity is low during a normal operation in which the filter regeneration operation or the like is not performed. In the area where the exhaust gas temperature is high and the trapped PM is burned by the catalytic action and the accumulated PM decreases (part B in FIG. 9), the catalyst (A part in FIG. 9) It means a portion (on the C line in FIG. 9) in a balanced state where neither PM accumulation nor reduction in the attached filter 4 occurs.

In step S13, it is determined whether or not the measured DPF inlet temperature Te is equal to or lower than the DPF inlet temperature Tb at the balance point. It is determined whether or not it is within the region (part A in FIG. 9).

In the determination in step S13, the measured DPF inlet temperature Te becomes the DPF at the balance point.
If the temperature is equal to or lower than the inlet temperature Tb, that is, if the temperature is within the PM accumulation region (A), the torque Q and the engine speed Ne are determined in step S14 from the PMa (Q, Ne) map of FIG. Its hourly deposited PM on the corresponding filter
The amount is calculated, added to the accumulated PM estimated value PMs and accumulated, and the process returns.

Further, in the determination in step S13, the measured DPF inlet temperature Te becomes the DPF at the balance point.
The temperature is higher than the inlet temperature Tb, that is, the PM reduction region (B in FIG. 9)
If it is within (part), the amount of PM to be removed corresponding to the torque Q and the engine speed Ne is calculated from the PMb (Q, Ne) map of FIG. Step S is performed by subtracting and accumulating the accumulated estimated value PMs.
Go to 16.

In this step S16, it is determined whether or not the PM accumulated estimated value PMs is larger than zero, that is, whether or not PM is in a state where PM is accumulated. Is smaller than zero, the process returns in step S17 with the accumulated PM value PMs set to zero, and if larger than zero, the process returns.

[Judgment of Start of Regeneration Mode Operation] In step S21 of FIG. 2, the PM accumulated estimated value PMs is equal to or larger than a predetermined PM judgment value PMmax, or the exhaust pressure Pe is set to a predetermined first exhaust pressure judgment value. It is determined whether it is more than Pemax.
More specifically, in the determination of the PM accumulated estimated value PMs, as shown in FIG. 10A, the PM accumulated estimated value PMs is between PM1 and PM2 and the operating state of the engine (torque Q, The engine speed Ne) is as shown in FIG.
10A, the PM cumulative estimation value PMs is in the shaded area (A) below the balance point of the PM2 and the PM2 in FIG.
When it is between M3 (in this case, the operating state of the engine (torque Q, engine speed Ne) is the hatched portion (A + B) in FIG. 10C, that is, in the full operating state), the regeneration mode It is controlled to enter operation.

[First Stage of Heating: Preheating] Then, FIG.
In step S32, the timing of the main injection (main) of the fuel injection is delayed (retarded) to increase the exhaust gas temperature by this delay operation. In step S32, as shown in the detailed flow of FIG. , Step S32
In a, the main injection is delayed, and the exhaust temperature is increased by the delay operation. In the next step S32b, the DPF inlet temperature (exhaust temperature) Te measured by the first temperature sensor 53 is set.
Is a predetermined first target temperature Te1 (for example, 200 to 250
Degrees Celsius), and if not,
In step S32c, the delay amount of the main injection of the fuel injection is increased, and the DPF inlet temperature Te is raised to the first target temperature Te1 or more by this delay operation.

When the DPF inlet temperature Te exceeds the predetermined first target temperature Te1 and exceeds a predetermined first time value t1 in step S32b, the process proceeds to step S33.

By increasing the temperature of the exhaust gas, preheating is performed to heat the oxidation catalyst 3 and the temperature of the catalyst is increased to activate the oxidation catalyst 3, thereby avoiding generation of white smoke due to the post-injection.

The main injection delay operation is continued until the end of the regeneration mode operation.

[Second Stage of Temperature Rise: Start of PM Combustion] In step S33 of FIG. 2, a post-injection (post-injection) is performed, and a specified amount of fuel is post-injected.
The exhaust gas temperature is increased until the F inlet temperature Te reaches the second target temperature Te2. The second target temperature Te2 is a temperature at which PM can be burned as shown in FIG. 9 and is a predetermined temperature (for example, 5 ° C) higher than the DPF inlet temperature Tb at the balance point.
0 ° C.) At a high temperature, about 250 ° C. to 350 ° C.

In this step S33, as shown in the detailed flow chart of FIG. 5, a post-injection of a specified amount is performed in step S33a, and the DPF inlet temperature Te is set to the second target temperature T
e2, and in the next step S33b, the exhaust pressure Pe
(Or differential pressure ΔPe) is equal to a predetermined second exhaust pressure value Pe2b.
The second target temperature Te2 is maintained by controlling the post-injection timing (injection timing) until the pressure becomes equal to or less than the second differential pressure value ΔPe2. Further, the injection amount may be controlled and maintained.

The exhaust pressure Pe is an exhaust pressure value measured by the first exhaust pressure sensor 51 on the exhaust inlet side of the oxidation catalyst 3, and the differential pressure ΔPe is the exhaust pressure P measured by the first exhaust pressure sensor 51.
e from the exhaust pressure Peb measured by the second exhaust pressure sensor 52 on the exhaust outlet side of the catalyst-equipped filter 4 ΔPe = Pe−Pe
b.

Then, in step S33c, the exhaust pressure Pe
(Or the differential pressure ΔPe) has become equal to or less than a predetermined second exhaust pressure value Pe2 (or the second differential pressure value ΔPe2), or the target temperature Te2 is reduced to a predetermined second time value t2 (for example, 3
00s), it is determined whether or not it is maintained. If it is either, the process proceeds to step S34. If it is not, the process returns to step S33b.

By the post-injection, the temperature of the filter with catalyst 4 is raised to start the combustion of PM.

Then, the fact that the combustion of PM is started,
The exhaust pressure Pe (or the differential pressure ΔPe) is equal to a predetermined second exhaust pressure value P.
It is confirmed that it is equal to or less than e2 (or the second differential pressure value ΔPe2).

[Third Stage of Temperature Rise: PM Combustion] In the next step S34 of FIG. 2, the post-injection injection amount is increased to raise the exhaust gas temperature so that the temperature becomes suitable for PM combustion.
That is, control is performed so that the DPF inlet temperature Te becomes the third target temperature Te3 higher than the second target temperature Te2. The third target temperature Te3 is a predetermined temperature (for example, 150 ° C.) higher than the DPF inlet temperature Tb at the balance point and is about 350 ° C. to 500 ° C.

In this step S34, as shown in the detailed flow of FIG. 6, the amount of post-injection injection is increased in step S34a, and in the next step S34b, the exhaust pressure Pe is increased.
The injection amount of the post-injection is controlled and the third target temperature Te3 is maintained until (or the differential pressure ΔPe) becomes equal to or less than the predetermined third exhaust pressure value Pe3 (or the third differential pressure value ΔPe3).

Then, in step S34c, the exhaust pressure Pe
(Or the differential pressure ΔPe) has become equal to or less than a predetermined third exhaust pressure value Pe3 (or a third differential pressure value ΔPe3), or the target temperature Te3 is reduced to a predetermined third time value t3 (for example, 6
It is determined whether the current state is maintained during the period of 00s). If any of the states is maintained, the process proceeds to step S35. Otherwise, the process returns to step S34b.

In step S34, PM combustion is performed at an optimum temperature by controlling the injection amount of the post-injection.

[Fourth Temperature Erasure: PM Elimination] In step S35 of FIG. 2, the injection amount of the post-injection is further increased.
When the PF inlet temperature Te becomes the fourth target temperature Te4 (for example, 600
℃).

In this step S35, as shown in the detailed flow of FIG. 7, the amount of post-injection injection is increased in step S35a, and in the next step S35b, the exhaust pressure Pe is increased.
Until the (or differential pressure ΔPe) becomes equal to or less than the predetermined fourth exhaust pressure value Pe4 (or the fourth differential pressure value ΔPe4), the injection amount of the post-injection is controlled to maintain the fourth target temperature Te4.

Then, in step S35c, the exhaust pressure Pe
(Or the differential pressure ΔPe) has become equal to or less than a predetermined fourth exhaust pressure value Pe4 (or the fourth differential pressure value ΔPe4), or the fourth target temperature Te4 is maintained for a predetermined fourth time value t4 (for example, 300 s). It is determined whether or not it has been maintained, and if so, the process proceeds to step S36,
If not, the process returns to step S35b.

By this temperature raising operation, the PM trapped in the filter is eliminated.

[End of Regeneration Mode Operation] Then, in step S36 shown in FIG. 2, the regeneration mode operation is ended, fuel injection is returned to normal, and the PM calculation accumulated value PMs is reset to zero.

At the end of the regeneration, the exhaust pressure Pe is checked and stored. When the exhaust pressure Pe exceeds a predetermined exhaust pressure value Pemax, a warning lamp is turned on to notify the driver that the filter life has expired.

[Others] At each stage of the above flow, the DPF inlet temperature Te is monitored and the limit temperature (Te
max: 700 ° C.) or more, the post-injection is stopped, the delay operation of the main injection is canceled, and the regeneration mode operation is interrupted. Avoid filter erosion.

At the same time, when the temperature Teb measured by the second temperature sensor 54 provided on the exhaust outlet side of the catalyst-equipped filter 4 becomes higher than a predetermined temperature, the torque is automatically reduced or the like. An engine operation operation for preventing the filter 4 from being damaged is performed.

When the regeneration process is interrupted, the PM is calculated from the exhaust pressure Pe 'at the end of the previous regeneration, the exhaust pressure Pe "at the start of the current regeneration, and the exhaust pressure Pe at the time of the interruption of the regeneration. The remaining amount PMs 'is estimated, and the remaining amount PMs'
It is adopted as the value at the start of the integration of the M accumulated estimated value PMs.

Further, the first exhaust pressure value Pemax, the second exhaust pressure value Pe2 (or the second differential pressure value ΔPe2), the third exhaust pressure value Pe3 (or the third differential pressure value ΔPe3), and the fourth exhaust pressure value Pemax. The relationship of the pressure value Pe4 (or the fourth differential pressure value ΔPe4) sequentially decreases in this order. That is, Pemax>Pe2> Pe
3> Pe4 (or ΔPe2>ΔPe3> ΔPe4)
In a relationship.

[Time Series of Regeneration] According to the regeneration control method of the continuous regeneration type DPF device 1 as described above, the filter with the catalyst in the time series of the DPF inlet temperature Te as shown in FIG. 4 is performed.

[0086] PM is accumulated during an engine operation such as a normal running state or an idling operation state, and a PM accumulated estimated value PM is accumulated.
s is greater than a predetermined determination value PMmax or the exhaust pressure Pe
Is larger than the predetermined first exhaust pressure value Pemax, the process shifts to the regeneration mode of step S30 according to the determination in step S21 of FIG.

At the start time ts of the regeneration mode, EGR (exhaust gas recirculation) is cut off in step S31, and the timing of the main injection (main) of fuel injection is delayed (retarded) in step S32. Raises the exhaust temperature.

Then, the DPF inlet temperature Te is set to the predetermined first
If the temperature exceeds the target temperature Te1 (about 200 to 250 ° C.), in step S33, post-injection (post-injection) is performed, a specified amount of post-injection is performed, and the DPF inlet temperature T
e to the second target temperature Te2 (about 350 ° C.),
Start burning PM.

Then, the fact that the combustion of PM has started is
The exhaust pressure Pe (or the differential pressure ΔPe) is equal to a predetermined second exhaust pressure value P.
When it is confirmed that the pressure becomes equal to or less than e2 (or the second differential pressure value ΔPe2), in step S34, the injection amount of the post-injection is increased, and the exhaust gas temperature becomes a temperature suitable for PM combustion.
The PF inlet temperature Te is the third target temperature Te3 (about 500 ° C.)
At the optimum temperature for PM combustion.
Combustion.

Then, it is confirmed that most of the accumulated PM has burned when the exhaust pressure Pe (or the differential pressure ΔPe) has become equal to or less than the predetermined third exhaust pressure value Pe3 (or the third differential pressure value ΔPe3). In step S35, the post-injection injection amount is further increased, and the PM trapped in the filter is cleaned.

Then, the exhaust pressure Pe (or the differential pressure ΔPe)
Is the predetermined fourth exhaust pressure value Pe4 (or the fourth differential pressure value ΔPe
4) It is confirmed that the combustion of PM has ended by the following conditions. In step S36, the regeneration mode operation is ended, the fuel injection is returned to normal, and the PM calculation accumulated value PMs is reset to zero.

By this series of regeneration control, regeneration of the filter with catalyst 4 is performed.

[0093]

As described above, according to the continuous regeneration type diesel particulate filter (DPF) apparatus and the regeneration control method of the present invention, the following effects can be obtained.

An oxidation catalyst provided on the upstream side of the catalyst-equipped filter of the continuous regeneration system allows carbon monoxide (C
O) and unburned fuel (HC) can be oxidized to raise the temperature of the exhaust gas flowing into the catalyst-equipped filter. The temperature of the filter can be raised, and the trapped particulate matter (PM) can be burned and removed.

In an engine operating state such as a low torque and a low rotational speed where the trapped particulate matter is not burned and removed in the normal operation, the exhaust operation is performed by the delay operation of the main injection timing of the fuel injection or the post-injection. By raising the gas temperature, PM can be burned and removed.

Therefore, the exhaust gas temperature is low, such as during a long idling operation, a low speed operation, or a downhill driving operation in which the engine brake is operated, and the trapped PM is not burned and removed. Even in an engine operating state such as a low torque and a low rotation speed, the P in the exhaust gas is continuously maintained without clogging the filter with the catalyst.
M collection can be performed.

Further, without using a heater, the combustion of PM is controlled by controlling the exhaust gas temperature by delaying the main injection of the fuel injection or by the post-injection. Since it can be performed by the device, new devices such as a heater and a power supply for heating and a control device for the device can be dispensed with, so that the device can be made compact.

Since the temperature of the exhaust gas entering the filter with a catalyst is increased in two or more stages, it is possible to prevent a sudden increase in the temperature due to chain rapid combustion of the deposited PM. Filter erosion can be avoided.

In addition, since the regeneration mode operation is started based on the calculated estimated value of PM, the regeneration process of the filter with the catalyst can be performed at an optimum timing. Therefore, it is possible to continuously and efficiently collect and burn the PM while preventing the fuel efficiency from deteriorating.

Further, at the start of the regeneration mode operation, the exhaust gas temperature is increased by delaying the timing of the main injection, the oxidation catalyst is preheated to activate this catalyst, and then the post-injection is performed. The generation of white smoke that tends to occur can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a continuous regeneration type particulate filter device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a regeneration control method of the continuous regeneration type particulate filter device according to the embodiment of the present invention.

FIG. 3 is a flowchart for estimating and calculating a PM accumulated estimated value.

FIG. 4 is a flowchart of a first stage of temperature rise of preheating due to delay of main injection of fuel injection.

FIG. 5 is a flowchart of a second stage of temperature rise at the start of PM combustion by a post-injection of a specified amount of fuel injection.

FIG. 6 is a flowchart of a third stage of temperature rise of PM combustion by increasing the amount of post-injection of fuel injection.

FIG. 7 is a flow chart of a fourth stage of the temperature rise of PM cleaning by further increasing the post-injection of fuel injection.

FIG. 8 is a time-series diagram showing a lapse of time of a DPF inlet temperature in the regeneration mode operation.

FIGS. 9A and 9B are diagrams showing map data of the PM amount used for calculating the PM accumulated estimated value, wherein FIG. 9A is a diagram showing a balance point, and FIG. (C) is a diagram showing a portion of the PM removal area (B) where map data exists.

10A and 10B are diagrams for determining a PM accumulated estimated value at the start of the regeneration mode operation. FIG. 10A is a diagram illustrating a relationship between a numerical value used for the determination and a regeneration interval, and FIG. 10B is a diagram illustrating PM1 ≦ PMs.
FIG. 9 is a diagram showing an engine operation area (B) at the time of <PM2;
(C) is a diagram showing an engine operating region (A + B) when PM2 ≦ PMs <PM3.

FIG. 11 is a diagram showing a relationship between an engine operating region (torque and engine speed) and a mechanism for purifying PM in exhaust gas in a conventional continuous regeneration type particulate filter device.

[Explanation of symbols]

 E engine 1 continuous regeneration type particulate filter device 2 exhaust passage 3 oxidation catalyst 4 filter with catalyst 5 fuel injection device 50 control device (ECU) 51 first exhaust pressure sensor 52 second exhaust pressure sensor 53 first temperature sensor 54 second Temperature sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneo Suzuki Eighth Tsurana, Fujisawa-shi, Kanagawa Prefecture Isuzu Motors Fujisawa Plant Co., Ltd. (72) Inventor Naofumi Ochi 8-Tsuchinashi, Fujisawa-shi, Kanagawa Isuzu Motors Fujisawa Plant, Inc. (72) Inventor Masashi Gabe 8 Tsurana, Fujisawa-shi, Kanagawa Prefecture Isuzu Motors Fujisawa Plant F-term (reference) 3G090 AA03 BA02 CA01 CB02 DA09 DA12 DB03 DB07 EA02 3G301 HA02 JA24 KA07 KA16 LB11 LC01 MA11 MA26 ND01 NE01 PA01Z PD12Z PD14Z PE01Z

Claims (10)

[Claims] 1. A continuously regenerating diesel particulate filter device comprising a filter with a catalyst for collecting particulate matter in exhaust gas of a diesel engine and burning the collected particulate matter by a catalytic action. A continuously regenerating diesel particulate filter device, comprising an oxidation catalyst for oxidizing HC and CO in exhaust gas to raise the temperature of the exhaust gas, on the upstream side of the filter. 2. A regeneration control means for performing a regeneration process for clogging of the catalyzed filter, wherein the regeneration control means operates under engine operating conditions in which an exhaust gas temperature of an engine is lower than an activation temperature of the oxidation catalyst. During regeneration of the catalyzed filter, the exhaust gas temperature is raised by fuel injection control of the engine to activate the oxidation catalyst, and the particulate matter trapped by the catalyzed filter is burned and removed. The continuous regeneration type diesel particulate filter device according to claim 1, wherein: 3. The continuous regenerative diesel particulate filter device according to claim 2, wherein the temperature of the exhaust gas is increased in two or more stages by the fuel injection control. 4. The continuous regenerative diesel particulate filter device according to claim 2, wherein the fuel injection control includes at least one of a main injection delay operation and a post-injection operation. 5. A filter with a catalyst that collects particulate matter in exhaust gas of a diesel engine and burns the collected particulate matter by a catalytic action, and an HC in the exhaust gas is provided upstream of the filter with the catalyst. And a continuous regenerative diesel particulate filter device having an oxidation catalyst for oxidizing CO and raising the temperature of the exhaust gas, wherein the engine operating conditions are such that the exhaust gas temperature of the engine is lower than the activation temperature of the oxidation catalyst. Wherein the exhaust gas temperature is increased by fuel injection control of an engine in order to burn and remove particulate matter trapped in the filter with a catalyst during regeneration of the filter with a catalyst. A regeneration control method for a particulate filter device. 6. The regeneration control method for a continuous regeneration type diesel particulate filter device according to claim 5, wherein the temperature rise of the exhaust gas by the fuel injection control is performed in two or more stages. 7. The continuous regeneration type diesel particulate filter device according to claim 5, wherein the fuel injection control includes at least one of a main injection delay operation and a post-injection operation. Playback control method. 8. At the time of the regeneration, the temperature of the exhaust gas is increased by first delaying the main injection of the fuel so that the temperature of the exhaust gas flowing into the catalyst-equipped filter becomes a predetermined first target temperature value. 8. The method according to claim 7, wherein the exhaust gas temperature is further increased by performing a post-injection operation of the fuel after the fuel gas reaches the temperature. 9. In the fuel post-injection operation, after the specified amount of fuel is post-injected and the temperature of the exhaust gas flowing into the catalyzed filter reaches a second predetermined target temperature value, the fuel is injected after the fuel. 9. The regeneration control method for a continuous regeneration type diesel particulate filter device according to claim 8, wherein the exhaust gas temperature is further increased by increasing the injection amount of the injection. 10. The amount of particulate matter accumulated in the catalyzed filter and the amount of particulate matter burned and removed during operation of the engine are estimated from the operating state of the engine, and are cumulatively calculated and calculated. The method according to any one of claims 5 to 9, wherein an estimated storage amount is calculated, and whether or not the estimated storage amount of the particulate matter exceeds a predetermined storage amount is used to determine the start of reproduction. A regeneration control method for the continuous regeneration type particulate filter device described in the above.