JP2003254044A - Regeneration control device for particulate filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regeneration control device for a particulate filter having a fail/safe function at a low cost which prevents a failure of a fuel consumption and can cope with a specific operation condition and an abnormality of various kinds of detection means. <P>SOLUTION: The regeneration control device for the particulate filter has a branched part (5) provided on a midway of an exhaust system (4); a plurality of branched pipes (6, 7) disposed in parallel at a downstream of the branched part (5); and a plurality of particulate filter (F1, F2) interposed on a plurality of branched pipes (6, 7). In the particulate filters (F1, F2), electric heaters (Fh1, Fh2) are provided at an upstream side and filter bodies (Ff1, Ff2) are provided at a downstream side. Directional control valves (V1, V2) are interposed at an area between the branched part (5) of a plurality of branched pipes (6, 7) and a plurality of particulate filters (F1, F2). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regeneration control device for an alternating regeneration type particulate filter using an electric heater of an internal combustion engine.

[0002]

2. Description of the Related Art So-called "particulate matter (P) contained in exhaust gas emitted from a diesel engine
M) ”for removing diesel particulate filter (DPF) (hereinafter, diesel particulate filter is abbreviated as DPF) is a catalyst system that removes PM trapped by the filter by the oxidizing action of the catalyst. Burner burns the soot collected by the burner (regenerates the filter) to remove PM contained in the soot, and burns the soot collected by the filter with an electric heater ( It is roughly classified into an electric heater system in which PM contained in soot is removed by regenerating a filter).

In the catalyst system, the filter body, which is a catalyst, is expensive, and the exhaust temperature of the catalyst is high (200 to 300 ° C.).
Otherwise, the function as a catalyst will not work. Therefore, when the engine is operated for a long time at a low speed and a low load, the soot is excessively accumulated and the filter is likely to be clogged, and the housing may be damaged.

The burner system has a burner with an amount of heat of about 100 to 200 kW and an auxiliary combustion pump, which makes the system complicated and expensive.

The electric heater system has no problem with the above-mentioned catalyst system and burner system, but since the capacity of the generator (generator) mounted on the vehicle is at most 2-3 kW,
The capacity of the electric heater is limited. However, the temperature of 600 ° C. or higher is required for burning the soot collected in the filter, and it is 2 when heating the exhaust gas through one filter while heating.
About 00 kW is required.

Therefore, a method has been proposed in which a plurality of DPFs are provided in parallel in the exhaust system, and when soot is accumulated, the soots are switched in order and regenerated by an electric heater.

If such filter regeneration (incineration of collected soot) by a plurality of electric heater type DPFs is performed when the soot is excessively collected, the filter temperature becomes too high,
This may cause cracking or melting of the filter.

On the other hand, if the soot is regenerated in a small amount, reproduction becomes defective. In addition, the frequency of energization increases and power consumption increases. Therefore, it is important to detect an accurate collection amount (soot clogging condition) while the engine is operating.

As an index showing the collected amount, a method of calculating the pressure loss coefficient every moment from the filter pressure loss, the engine rotation, the intake pressure and the like is effective.

However, in the case of idling for a long time or low speed operation, on the contrary, continuous high speed operation, or due to signal anomalies of various sensors, the filter before the estimated calculation value (pressure loss coefficient) of the trapped amount reaches the set value. If the previous pressure becomes abnormally high, the back pressure of the engine will become too high, fuel consumption will deteriorate, and the DPF casing and the exhaust pipe may be damaged.

Further, there is a problem that fail-safe is not established when the clogging cannot be detected normally due to a malfunction of the pressure detecting means itself.

[0012]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, is inexpensive, can prevent deterioration of fuel consumption, can cope with special driving conditions, and can be used as various detecting means. An object of the present invention is to provide a particulate filter regeneration control device having a fail-safe function capable of coping with the above abnormality.

[0013]

A particulate filter regeneration control device according to the present invention is arranged in parallel with a branch portion (5) provided in the middle of an exhaust system (4) and downstream of the branch portion (5). Control of a particulate filter having a plurality of branched pipes (6, 7) and a plurality of particulate filters (F1, F2) interposed in each of the plurality of branched pipes (6, 7) In the apparatus, the particulate filter (F1, F2) is provided with an electric heater (Fh) on the upstream side.
1, Fh2) to the downstream side of the filter body (Ff1, Ff
2) is installed, and a switching valve (V1, V2) is interposed in a region between the branch portion (5) of each of the plurality of branch pipes (6, 7) and the plurality of particulate filters (F1, F2). It is characterized by wearing.

Further, the particulate filter (DPF) regeneration control device of the present invention comprises a control means (9) and a pressure detection means (Sa) for detecting the pressure upstream of the particulate filters (F1, F2) and the atmospheric pressure. , Sp), engine speed detection means (Sn) and engine intake pressure sensor (Sb), and the control means (9) outputs the output signal of the pressure detection means (Sp) and the engine speed. The soot collection amount is estimated by the detection signal of the detection means (Sn), and the switching valve (V1 or V2) on the filter (Ff1 or Ff2) side where the estimated collection amount exceeds a predetermined value is closed and the same side is closed. Electricity to the electric heater (Fh1 or Fh2) is regenerated (regeneration of the filter) for a predetermined time, and a switching valve (V2 or V1) on another filter (Ff2 or Ff1) side
It is characterized by controlling to open. Further, according to the present invention, the filter pressure loss is calculated from a plurality of pressure detecting means, and when it exceeds a predetermined value, the filter pressure loss is regenerated. And according to the present invention, when the collection time exceeds a predetermined value, it is regenerated.

In the control method of the regeneration control device for the particulate filter "PF" having the above-mentioned structure, the control means (9) determines whether or not the various sensors (Sp, Sn, Sa, Sb) are abnormal. The abnormality generation determination step (S3) for determining whether or not any of the various sensors (Sp, Sn, Sa, Sb) is abnormal, and the electric heater (F
It is desirable to include an energization interruption step (S4) of deenergizing h1 and Fh2) (FIG. 2).

Further, in the control method of the regeneration control device for the particulate filter "PF" having the above-mentioned structure, the control means (9) has the pressure detection means (Sp, Sa, Sb).
And the soot clogging amount of the filters (Ff1, Ff2) is estimated and calculated based on the output signal from the engine speed detecting means (Sn), and it is determined whether or not the soot clogging amount is equal to or greater than a predetermined value. Soot clogging amount determination process (S11, S12, S1
3) and a switching valve switching step (S14) of switching the switching valve (V1, V2) when the soot clogging amount is equal to or larger than a predetermined value.
It is desirable to include an energization interruption step (S16) of de-energizing the electric heaters (Fh1, Fh2) when the clogging amount of soot is not more than a predetermined value (FIG. 3).

Here, when the filter soot clogging amount is estimated and calculated, it can be calculated by the engine speed and intake pressure at every moment and the pressure loss (pressure difference before and after the filter) at "PF" at that time. .

Further, in the control method of the regeneration control device for the particulate filter "PF" having the above-mentioned structure, the control means (9) has the particulate filters (F1, F).
2) Duty control step (S2) in which the current of the heaters (Fh1, Fh2) is duty controlled according to the upstream temperature.
2), an elapsed time determination step (S24) for determining whether or not the regeneration time has become a predetermined value or more, and the heaters (Fh1, Fh2) are de-energized when the regeneration time has become a predetermined value or more. It is desirable to include the energization interruption step (S25) (FIG. 4).

According to the regeneration control device for a diesel particulate filter of the present invention having the above-described structure, the diesel particulate filter regeneration control device is provided with a plurality of particulate filters (F1, F2) in which electric heaters (Fh1, Fh2) are installed. Since they are alternately collected and regenerated, the individual particulate filters can be downsized and can be easily mounted on the vehicle.

When reproducing the filters (Ff1, Ff2), a plurality of particulate filters (F1, F2) are used.
It is sufficient to sequentially close and regenerate one of the above, and therefore the power required for regeneration can be greatly suppressed and the existing generator can be used.

The control means (9) is, for example, a pressure detecting means (Sp, Sa, Sb) and an engine speed detecting means (S).
n), the amount of soot clogging of the filter is estimated and calculated, and when the amount of soot clogging is equal to or greater than a predetermined value, the switching valve (V1, V2) is switched so that the amount of soot clogging becomes a predetermined value. Otherwise, the electric heater (Fh1, Fh2)
Is controlled so that it is not energized, so that damage to the filters (F1, F2) due to excessive trapping of soot can be prevented. Also, the filter pressure loss is calculated from a plurality of pressure detecting means, and if it exceeds a predetermined value, it is regenerated, or if the collection time exceeds a predetermined value, it is regenerated. In the case of low speed operation or, conversely, continuous high speed operation,
Alternatively, if the pressure before the filter becomes abnormally high before the estimated calculation value (pressure loss coefficient) of the collected amount reaches the set value due to the signal abnormality of various sensors, the back pressure of the engine becomes too high or the fuel consumption is reduced. Does not become worse or the DPF casing or the exhaust pipe is not damaged.

The regeneration control method of the particulate filter (F1, F2) of the control means (9) is based on the electric heater when various detection means (sensors Sp, Sn, Sa, Sb) become abnormal. Since it has a fail-safe function of de-energizing (Fh1, Fh2), even if an abnormality occurs, the heater or the like is not damaged.

The control means (9) controls the heater (Fh) according to the temperature upstream of the particulate filters (F1, F2).
Since the current of (1) and (Fh2) is duty controlled, it is possible to minimize power consumption and prevent burnout of the heater and melting damage of the filter body due to overheating.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the first embodiment will be described with reference to FIGS. An exhaust pipe 4 is connected to an exhaust manifold 2 of the engine 1 via a turbocharger 3. A branch portion 5 is connected to the exhaust pipe 4, and a first branch pipe 6 and a second branch pipe 7 are connected to the branch portion 5. Then, the rear end 6a of the first branch pipe 6 and the rear end 7a of the second branch pipe 7 are connected so as to merge into one tail pipe 8.

The first branch pipe 6 is provided with a first switching valve V1 on the upstream side and a first diesel particulate filter "DPF" on the downstream side (in claims 1 and 2, the particulate filter: hereinafter, The diesel particulate filter is abbreviated as "DPF") F1. The second branch pipe 7 is provided with a second switching valve V2 on the upstream side and a second "DPF" F2 on the downstream side.

The first "DPF" F1 contains "DP
The first casing Fa1 constituting the F ”is provided on the upstream side of the first casing Fa1.
The electric heater Fh1 of the first filter main body F on the downstream side.
It is equipped with f1. In the second "DPF" F2, a second electric heater Fh2 is installed on the upstream side of the second casing Fa2 forming the "DPF" and a second filter body Ff2 is installed on the downstream side. .

A pressure sensor Sp, which is a detecting means for detecting the filter upstream pressure, is attached to the branch portion 5.
Further, the engine 1 is provided with an engine rotation sensor Sn for detecting the engine speed. The pressure sensor Sp and the engine rotation sensor Sn are both connected to the controller 9 as a control means by an input signal line Li.

A first solenoid valve (for actuation of the solenoid valve) is provided with a first solenoid valve SV1 on the first switching valve V1.
The air supply line La1 communicates. Further, a second (for operating the solenoid valve) air supply line La2 having a second solenoid valve SV2 interposed therein communicates with the second switching valve V2.

The first solenoid valve SV1 and the second solenoid valve SV2 are connected to the controller 9 by an output signal line Lo.

The first electric heater Fh1 and the second electric heater Fh2 supply the electric power of the battery 30 or the electric power generated by the generator 20 driven by the engine 1 through the controller 9. It is supplied by lines Le, Ld. In the figure, F is a fuse.

Immediately before the first filter body Ff1 and immediately before the second filter body Ff2, a first temperature sensor T1 for detecting the temperature of the filter and a second temperature sensor T1 for detecting the temperature of the filter, respectively.
Temperature sensor T2 is installed, and both are connected to the controller 9 by a signal line Lt.

The main control (control including the fail safe function) routine will be described with reference to FIG. In the following, a case where the first “DPF” F1 is trapped and concentrated will be described as an example.

In step S1, the controller 9 reads the parameters, which are the data from the detection means Sp and Sn, and proceeds to step S2.

In step S2, the controller 9 determines whether or not an error or abnormality has occurred, and if it has occurred (YES in step S2), the process proceeds to step S3, and if it has not occurred (NO). ), And proceeds to step S5.

In step S3, the controller 9 displays an error and gives a warning by, for example, activating an alarm (not shown), and proceeds to the next step S4. In step S4, the heater (first electric heater) Fh1 on the "DPF" F1 side is de-energized to end the control.

In step S5, the controller 9 determines whether or not the engine is rotating based on the information from the engine rotation sensor Sn. If the motor is rotating (YES in step S5), the process proceeds to step S6. If the motor is not rotating (NO in step S5), the above-described step S4 is performed.
The following control is performed.

In step S6, the controller 9 determines whether or not the filter body Ff1 in the first "DPF" F1 is being regenerated. If regeneration is in progress (YES in step S6), the filter regeneration operation is set and the control ends. When not playing (NO in step S6)
Sets the collection operation and ends the control.

According to the diesel particulate filter regeneration control apparatus of the first embodiment having such a configuration and control method, a plurality of "DPFs" F1 and F2 in which electric heaters Fh1 and Fh2 are installed are provided alternately. Since the "DPF" is collected and regenerated, each "DPF" can be miniaturized and easily mounted on the vehicle.

When the filters Ff1 and Ff2 are regenerated, one of the plurality of "DPFs" F1 and F2 may be regenerated in order, so that the electric power required for the regeneration can be greatly suppressed and the existing generator can be used. Can be used.

Further, various sensors Sp, Sn, Sa,
When Sb becomes abnormal, the electric heaters Fh1, Fh
Since it has a fail-safe function for de-energizing 2, it is possible to prevent damage to the "DPF" F1 and F2 even when an abnormality occurs.

Next, the collection operation routine will be described with reference to FIG. 3 and also with reference to FIG. Incidentally, FIG. 3 is similar to FIG.
The case where the “DPF” F1 of 1 is a trap concentration will be described as an example.

In step S11, the controller 9
Determines whether the soot clogging amount exceeds a predetermined value. If it exceeds the predetermined value (YE in step S11)
S), the process proceeds to step S14, and if not exceeded (NO in step S11), the process proceeds to step S12.

In step S12, the controller 9
Determines based on the information from the pressure sensor Sp whether or not the pressure loss of the first filter body Ff1 exceeds a predetermined value. If it exceeds (YES in step S12),
Proceed to step S14, and if not exceeded (step S14
No. 12), the process proceeds to step S13.

Here, the pressure loss of the filter body means the pressure loss at the front and rear ends of the filter, that is, the engine intake pressure sensor S.
It is the pressure difference between b and the filter downstream pressure sensor Sa. However, the pressure sensor Sa can be replaced by atmospheric pressure.

In step S13, the controller 9 determines whether or not the collection operation duration time exceeds a predetermined value. If it exceeds (YES in step S13), the process proceeds to step S14. If not (NO in step S13), the process proceeds to step S16.

In step S14, the controller 9
Sends a control signal to open and close the switching valves V1 and V2 (reverse at the start of reproduction of F2). Then, the process proceeds to step S15, and the "DPF" F1 is set for regeneration operation.

In step S16, the controller 9 cuts off the power supply to the first electric heater Fh1 and ends the control.

According to the regeneration control device for the diesel particulate filter which performs such control, the filter soot is clogged based on the output signals of the pressure detecting means Sp, Sa, Sb and the engine speed detecting means Sn. The estimated amount is calculated, and when the soot clogging amount is a predetermined value or more, the switching valve V1 or V2 is closed and the electric heater Fh1 or Fh2 is closed.
The electric heater Fh1 or Fh2 is controlled so as not to be energized when the soot clogging amount is not larger than a predetermined value.
1, the damage of F2 can be prevented.

Next, the control of the filter regeneration operation will be described with reference to FIG. 4 and also with reference to FIG. It should be noted that FIG. 4 will be described as an example when the first “DPF” F1 is reproduced, as in FIG.

In step S21, the temperature of the front end portion of the first filter body Ff1 is detected by the first temperature sensor, and in the next step S22, the controller 9 determines the first electric heater Fh1 according to the detected temperature. Duty control the current value of.

In the next step S23, the controller 9 outputs a signal of "reproducing" and the next step S24.
Proceed to.

In step S24, the controller 9 determines whether or not the elapsed playback time has exceeded a predetermined value. If it exceeds the predetermined value (YES in step S24), the process proceeds to step S25, the power supply to the first electric heater Fh1 is cut off, and the control ends. If it does not exceed the predetermined value (NO in step S24), the process returns to step S22.

[D] of the third embodiment for performing such control
According to the reproduction control device of "PF", "DPF" F1, F2
Since the current of the heater is duty-controlled according to the upstream temperature, power consumption can be minimized and melting damage of the filter body due to overheating can be prevented.

The illustrated embodiment is merely an example,
It is additionally noted that the description is not intended to limit the technical scope of the present invention. For example, although the particulate filter is used in the diesel engine in the embodiment, the particulate filter may be applied to other internal combustion engines.

[0056]

The effects of the present invention will be described below. (A) Since a plurality of particulate filters equipped with an electric heater are provided to alternately collect and regenerate, the individual particulate filters can be downsized and can be easily mounted on a vehicle. (B) When the filter is regenerated, one of the plurality of particulate filters may be regenerated in order, so that the electric power required for regeneration can be significantly suppressed and the existing generator can be used. (C) The soot clogging amount of the filter is estimated and calculated based on the output signals of the pressure detecting means and the engine speed detecting means, and when the soot clogging amount is not equal to or more than a predetermined value, the electric heater is de-energized. Therefore, it is possible to prevent the filter from being damaged due to excessive collection of soot. (D) Since it has a fail-safe function of de-energizing the electric heater when various detecting means become abnormal, damage to the filter can be prevented even if an abnormality occurs. (E) Since the current of the heater is duty controlled according to the temperature upstream of the particulate filter, power consumption can be minimized and melting damage of the filter body due to overheating can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of first to third embodiments of the present invention.

FIG. 2 is a control flowchart showing a main control routine of the present invention.

FIG. 3 is a control flowchart showing a collection operation routine of the present invention.

FIG. 4 is a control flowchart showing a filter regeneration operation routine of the present invention.

[Explanation of symbols]

1 ... engine 2 ... Exhaust manifold 4 ... Exhaust pipe 5 ... Branch 6 ... First branch pipe 7 ... Second branch pipe 9 ... Controller F1, F2 ... First and second DPF Ff1, Ff2 ... First and second filter bodies Ff1, Ff2 ... First and second electric heaters V1, V2 ... First and second switching valves Sa ... Filter downstream sensor Sb: Engine intake pressure sensor Sn ... Engine rotation sensor Sp ... Pressure sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takamichi Koike             1-chome Ichichome, Ageo City, Saitama NISSAN DI             Within Hazel Industry Co., Ltd. (72) Inventor Hisashi Akakawa             1-chome Ichichome, Ageo City, Saitama NISSAN DI             Within Hazel Industry Co., Ltd. F term (reference) 3G090 AA02 AA04 BA04 CA01 CB12                       CB18 CB23 DA03 DA13 DA18                       DA20

Claims (4)

[Claims] 1. A branch part provided in the middle of an exhaust system, a plurality of branch pipes arranged in parallel downstream of the branch part, and a plurality of particulate filters interposed in each of the plurality of branch pipes. In the particulate filter regeneration controller, the particulate filter includes an electric heater on the upstream side and a filter main body on the downstream side, and the branch portion of each of the plurality of branch pipes and the plurality of particulates. A regeneration control device for a particulate filter, characterized in that a switching valve is provided in a region between the filters. 2. A control means, a plurality of pressure detection means for detecting a pressure upstream of the particulate filter and an engine intake pressure, and an engine speed detection means,
The control means estimates the particulate collection amount by the output signal of the pressure detection means and the detection signal of the engine speed detection means, and a switching valve on the filter side where the estimated collection amount exceeds a predetermined value. 2. The regeneration control device for a particulate filter according to claim 1, wherein the regeneration control device for the particulate filter is closed and energized to the electric heater on the same side for a predetermined time to open the switching valve on the other filter side. 3. The regeneration control device for a particulate filter according to claim 2, wherein the filter pressure loss is calculated from a plurality of pressure detecting means, and when the filter pressure loss exceeds a predetermined value, the filter pressure loss is regenerated. 4. The particulate filter regeneration control device according to claim 2, wherein regeneration is performed when the collection time exceeds a predetermined value.