JP2002364342A - Regenerator for diesel particulate filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regenerator for a diesel particulate filter (hereinafter referred to as 'DPF') having a simple structure and capable of judging regeneration start time with high precision. SOLUTION: This regenerator for DPF is provided with a pressure sensor mounted on the downstream end side of an exhaust system of an engine to detect a pressure on the inlet side of DPF, an atmospheric pressure sensor for detecting an atmospheric pressure, a rotary sensor for detecting the number of revolutions of the engine, a filter regenerating means for combusting and removing particulates caught by DPF, and a control means for inputting values detected by each sensor and storing a pressure loss threshold value map set in advance based on the number of revolutions of the engine and filter pressure loss. The control means calculates filter pressure loss based on the values detected by the pressure sensor and the atmospheric pressure sensor and operates the filter regenerating means when the calculated value exceeds a pressure loss threshold value in the pressure loss threshold value map corresponding to the value detected by the rotary sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for regenerating a diesel particulate filter.

[0002]

2. Description of the Related Art Exhaust gas emitted from a diesel engine contains a large amount of particulates (fine particle components such as carbon particles).
In purifying exhaust gas of an "engine", it is essential to remove the particulates.

Accordingly, as disclosed in Japanese Patent Application Laid-Open Nos. 9-13951 and 8-277710,
Recently, a diesel particulate filter (hereinafter referred to as “DPF”) has been installed in an exhaust system of an engine,
PF collects particulates to purify exhaust gas. Also, as the collection of particulates progresses, DP
F is clogged and the flow path resistance increases, so the DPF
DPF is regenerated by burning and removing the particulates collected by the regenerating means such as an electric heater, etc., and in the conventional example disclosed in JP-A-9-13951, the relationship between the exhaust flow rate and the filter pressure loss The start time of DPF regeneration is determined from the relationship between the exhaust pressure at or near the exhaust manifold and the pressure detected at the DPF inlet in the conventional example disclosed in Japanese Patent Application Laid-Open No. 8-277710. The timing has been determined.

[0004]

SUMMARY OF THE INVENTION
A conventional example disclosed in Japanese Patent Application Publication No. -13951 discloses an intake flow rate sensor for detecting an intake air flow rate of an engine, an exhaust temperature sensor for detecting an exhaust temperature, and an exhaust pressure for detecting a pressure loss of two DPFs mounted on an exhaust system. There is a drawback that the apparatus becomes very complicated due to the structure in which the sensors are mounted at predetermined positions and the exhaust flow rate is obtained by the control means from the detected values.

In the conventional example disclosed in Japanese Patent Application Laid-Open No. 8-277710, an exhaust manifold and a DPF are disclosed.
It has been pointed out that the detection is difficult when the distance between them is short and the pressure difference is small, and the accuracy is lowered. The present invention has been devised in view of such circumstances, and an object of the present invention is to provide a DPF reproducing apparatus capable of accurately determining a reproduction start time with a simple structure.

[0006]

According to a first aspect of the present invention, there is provided a DPF regeneration apparatus for detecting a pressure at an inlet of a DPF mounted at a downstream end of an exhaust system of an engine. And an atmospheric pressure sensor for detecting atmospheric pressure;
A rotation sensor for detecting the number of revolutions of the engine, a filter regeneration means for burning and removing the particulate matter trapped in the DPF, a detection value of each of the above sensors, and presetting based on the number of revolutions of the engine and the filter pressure loss Control means storing the detected pressure loss threshold map. The control means calculates a filter pressure loss from the detection values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is a pressure loss corresponding to the detection value of the rotation sensor. When the pressure drop threshold in the threshold map is exceeded,
Activating the filter regeneration means.

According to a second aspect of the present invention, there is provided a pressure sensor for detecting a pressure on an inlet side of a DPF mounted on an exhaust system of an engine, an atmospheric pressure sensor for detecting an atmospheric pressure, and a rotational speed of the engine. A rotation sensor, a parameter sensor for detecting a parameter representing an engine load, a filter regeneration means for burning and removing the particulate matter trapped in the DPF, a detection value of each of the above sensors, and an engine speed and a filter. Control means for storing a pressure loss threshold map preset based on the pressure loss and the parameters, the control means calculates a filter pressure loss from detection values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is a parameter When the pressure loss threshold value of the pressure loss threshold map according to the detection values of the sensor and the rotation sensor is exceeded, the filter regeneration unit is activated. And wherein the door.

The invention according to claim 3 is based on claim 2
In the DPF regeneration device described above, the parameter representing the engine load is the engine load itself. According to a fourth aspect of the present invention, in the DPF regeneration device according to the second aspect, the engine load is reduced. 6. The system according to claim 5, wherein the parameter to be represented is an engine boost pressure.
In the DPF regeneration apparatus according to the second aspect, the parameter representing the engine load is an exhaust temperature of the engine.

According to the first aspect of the present invention, the control means calculates the filter pressure loss from the detected values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is a pressure loss corresponding to the detected value of the rotation sensor. When the pressure loss threshold value in the threshold value map is exceeded, the filter regeneration means is operated to regenerate the DPF.

According to the second aspect of the present invention, the control means calculates the filter pressure loss from the detected values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is based on the detected values of the parameter sensor and the rotation sensor. When the pressure loss threshold value in the pressure loss threshold map is exceeded, the filter regeneration means is operated to regenerate the DPF. In the invention according to claim 3, the engine load itself functions as a parameter representing the engine load, and in the invention according to claims 4 and 5, the boost pressure and the exhaust temperature each function as parameters representing the engine load. .

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of a DPF regeneration apparatus according to claim 1, wherein 1 is an exhaust manifold mounted on an engine 3, and 5 is an exhaust pipe connected to the exhaust manifold 1. Downstream exhaust system is 2
The branch pipes 7 and 9 and one bypass pipe 11 are branched, and DPFs 13 and 15 are mounted on the branch pipes 7 and 9, respectively, and the downstream side of the DPFs 13 and 15 is open to the atmosphere.

The branch pipes 7 and 9 have DPFs 13 and
Butterfly valves 17 and 19 are mounted downstream of 15, and a butterfly valve 21 is mounted in the bypass pipe 11, and each of the butterfly valves 17, 19 and 21 is mounted.
Are opened and closed by solenoid valves 25 and 27 which are operated by commands from the control unit 23, respectively.

In the figure, 29 and 31 are DPFs 13 and 1 respectively.
5, an electric heater for regeneration mounted in the casing 33 of the control unit 23, and a heater control unit 23a of the control unit 23.
Are connected to both electric heaters 29 and 3 via a power unit 34.
For example, when the butterfly valves 17 and 21 are closed and the butterfly valve 19 is opened according to a command from the control unit 23, the exhaust gas discharged from the engine 1 flows down the exhaust pipe 5 and the branch pipe 9. When the particulates in the exhaust gas are collected by the DPF 15 and the electric heater 29 operates in this state, the DPF 1
3 are burned and removed to regenerate the DPF 13.

When the amount of trapped particulates by the DPF 15 increases and the filter pressure loss increases, the control unit 23 closes the butterfly valve 19,
By opening the butterfly valve 17 and operating the electric heater 31, the exhaust gas flows down to the branch pipe 7, and while collecting particulates in the exhaust gas with the DPF 13, the DPF 13
Burn and remove the particulates collected in step 15
The regeneration device 35 according to the present embodiment uses the heaters 29 and 31 to reproduce the DPF 1.
When performing the regeneration of 3, 15, the regeneration start timing is determined using a pressure loss threshold map as described below.

As in the prior art, the butterfly pipe 21 is opened by an instruction from the control unit 23 in an emergency and the exhaust gas flows down in the bypass pipe 11 as in the prior art. That is, generally, in order to calculate the filter pressure loss of the DPF, the pressure on the inlet side and the outlet side of the DPF is detected by a pressure sensor, and the filter pressure loss is calculated from these detected values. Therefore, the reproducing apparatus 35 according to the present embodiment also includes the branch pipe 7, as shown in FIG.
9 and a pressure sensor 39 on the upstream side of the branch portion 37 of the bypass pipe 11, and the DPF 13, 1
5, the pressure on the inlet side is detected, and the detected value Pf is input to the control unit 23.

On the other hand, as described above, since the downstream side of the DPFs 13 and 15 is open to the atmosphere, the DPFs 13 and 15 are open to the atmosphere.
Is equal to the atmospheric pressure. Therefore, in the present embodiment, the atmospheric pressure is detected by the pressure sensor (atmospheric pressure sensor) 41, and the detected value Pa is input to the control unit 23. Then, the control unit 23 calculates the DP at the time of particulate collection based on the two detection values Pf and Pa.
The filter pressure loss ΔP of F13, F15 is calculated by the following formula: ΔP = Pf−Pa.

Generally, in a naturally aspirated engine, the exhaust gas flow rate is proportional to the engine speed, and the filter pressure loss is proportional to the exhaust gas flow rate. When the amount of trapped particulates in the DPFs 13 and 15 increases, the filter pressure loss increases.
An increase in the amount collected by the PF can be detected. As described above, in the conventional example of Japanese Patent Application Laid-Open No. 9-13951, the exhaust gas flow rate is obtained from the detection values of many sensors to determine the DPF regeneration start timing. Instead of the flow rate, a pressure loss threshold map based on the engine speed and the filter pressure loss is set in advance as shown in FIG. 2 or FIG.

2 and 3 are pressure drop threshold maps in which the horizontal axis represents the engine speed N and the vertical axis represents the filter pressure drop ΔP, and FIG. 3 sets the pressure drop threshold in a stepwise manner. FIG.
Is a line graph taking the middle of the pressure loss threshold value of FIG. 3 set in a stepwise manner. Also, as shown in FIG. 1, the engine speed detected by the rotation sensor 43 is usually input to the engine ECU 45, and the engine ECU 45 detects the detected value of the rotation sensor 43 and the load sensor (not shown). The fuel injection pump 47 is controlled based on the detected value. Therefore, in the present embodiment, the engine speed is input from the engine ECU 45 to the control unit 23.

Then, for example, the butterfly valves 19 and 2
1 is closed, the butterfly valve 17 is opened, the exhaust gas flows down the branch pipe 7, and when particulates are collected by the DPF 13, the control unit 23 calculates the engine speed N input from the engine ECU 45 and By comparing the calculated filter pressure loss ΔP, the DPF
When it is determined that the filter pressure loss ΔP of FIG. 13 exceeds the pressure loss threshold value P of the pressure loss threshold map of FIG. 2 or FIG. 3, that is, the calculated filter pressure loss ΔP is in the region A of FIG. 2 or FIG. When the determination is made, the butterfly valve 17 is closed and the heater 29 is operated, and at the same time, the butterfly valve 19 is opened to allow the exhaust gas to flow down to the branch pipe 9 side.

Therefore, the particulate in the exhaust gas is D
The particulate matter in the DPF 13 is collected by the PF 15, and at this time, the particulate matter in the DPF 13 is burned and removed by the heater 29, so that the DPF 13 is regenerated. In addition, each heater 29, 31
Are equipped with temperature sensors 49 and 51, respectively.
These detected values are input to the temperature detecting section 23b of the control unit 23.

When the temperature of the heaters 29, 31 reaches a predetermined value, the control unit 23
The power supply to the heaters 9 and 31 is stopped, and the temperature of the heaters 29 and 31 is controlled.

In this embodiment, the control unit 23 closes, for example, the butterfly valves 19 and 21 and opens the butterfly valve 17 during running of the vehicle, so that the exhaust gas flows down the exhaust pipe 5 and the branch pipe 7 when the vehicle is running. Let
The particulates in the exhaust gas are collected by the DPF 13. Thus, with the collection of particulates, DPF1
Although the filter pressure loss of No. 3 rises, as shown in step S1 of FIG. 4, the control unit 23 takes in the engine speed N during traveling from the engine ECU 45 and at the same time takes in data from each of the pressure sensors 39 and 41.

Then, in step S2, the control unit 23 calculates the filter pressure loss ΔP from the calculation formula, and the filter pressure loss ΔP of the DPF 13 corresponding to the engine speed N is determined by the pressure loss threshold of FIG. 2 or FIG. It is determined whether or not the pressure loss threshold value P of the value map is exceeded. Then, in step S2, when it is determined that the calculated filter pressure loss ΔP is in the region A of FIG. 2 or FIG. 3, the control unit 23 proceeds to step S3 to close the butterfly valve 17 to activate the heater 29, and At the same time, the butterfly valve 19 is opened to allow the exhaust gas to flow down to the branch pipe 9 side.

Therefore, the particulate in the exhaust gas is D
The particulate matter in the DPF 13 is collected by the PF 15, and at this time, the particulate matter in the DPF 13 is burned and removed by the heater 29, so that the DPF 13 is regenerated. As described above, the temperature sensors 49 and 51 are mounted on the heaters 29 and 31, respectively, and the control unit 23
When the temperature of the heater 9 reaches a predetermined value, the power supply to the heater 29 is stopped, and the temperature of the heater 29 is controlled.

Hereinafter, the control unit 23 calculates the filter pressure loss ΔP from the calculation formula, and the filter pressure loss ΔP of the DPF 15 according to the engine speed N is determined by the pressure loss threshold in the pressure loss threshold map of FIG. 2 or FIG. While determining whether or not the value exceeds the value P, the DPF 1
5 and the DPF 13 are sequentially performed.

As described above, this embodiment corresponds to FIG. 2 or FIG.
DPF13, using a simple two-dimensional pressure loss threshold map based on the engine speed N and the filter pressure loss ΔP
Since the playback start time is determined in step 15,
Compared to the conventional example of Japanese Patent Application Laid-Open No. Hei 9-13951, the exhaust flow rate is obtained from the detected values of the intake air flow rate sensor, the exhaust temperature sensor, and the exhaust pressure sensor to determine the regeneration start time, while simplifying the configuration of the entire apparatus. It is possible to determine the reproduction start timing with high accuracy, and there is an advantage that the reproduction start time can be determined with high accuracy without the risk of the disadvantages of the conventional example of JP-A-8-277710. .

FIG. 5 shows an engine 3-1 equipped with a turbocharger 53 equipped with a turbocharger.
This embodiment will be described below with reference to the drawings. However, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In the engine 3-1 with a turbo, as compared with the naturally aspirated engine 3 in FIG. 1, since the exhaust gas flow rate generally changes depending on the engine load, only the engine speed N and the filter pressure loss .DELTA. In the two-dimensional pressure drop threshold map of
The reproduction start time of F cannot be accurately determined.

The parameters representing the engine load include not only the engine load itself but also the boost pressure and the exhaust temperature. That is, when a load is applied to the engine,
The fuel injection amount of the engine increases, the exhaust gas flow rate increases,
Turbocharger turbines rotate, boost pressure rises, and exhaust temperature rises.

For this reason, the detection of the boost pressure and the exhaust temperature as well as the direct detection of the engine load leads to the detection of a change in the engine load, and these function as parameters representing the engine load. Therefore, in the embodiment shown in FIG. 5, a pressure sensor 57 for detecting the boost pressure of the engine 3-1 is attached to the upstream exhaust pipe 61 of the intake manifold 59 in addition to the configuration of FIG. The detection value of the sensor 57 is stored in the control unit 23.
-1 is input.

In the memory of the control unit 23-1, a three-dimensional pressure loss threshold map based on the engine speed N, the filter pressure loss ΔP and the boost pressure is preset and stored as shown in FIG. For example, when the butterfly valves 19 and 21 are closed and the butterfly valve 17 is opened and the exhaust gas flows down the branch pipe 7 and particulates are collected by the DPF 13, the control unit 23-1 operates at the engine speed N. And the filter pressure loss ΔP calculated by the formula and the boost pressure detected by the pressure sensor 57, and the filter pressure loss ΔP of the DPF 13 is calculated.
If it is determined that P has exceeded the pressure loss threshold value P-1 in the pressure loss threshold map shown in FIG. 6, the butterfly valve 17 is closed and the heater 29 is operated, and at the same time, the butterfly valve 19 is operated.
And the exhaust gas is caused to flow down to the branch pipe 9 side.

Therefore, similarly to the regenerating device 35 shown in FIG. 1, the particulates in the exhaust gas are collected by the DPF 15, and at this time, the particulates of the DPF 13 are burned and removed by the heater 29 to regenerate the DPF 13. Become. In this embodiment, the control unit 23-1 closes the butterfly valves 19 and 21 and opens the butterfly valve 17 to allow the exhaust gas to flow down the exhaust pipe 5 and the branch pipe 7 when the vehicle is running. Then, the particulates in the exhaust gas are collected by the DPF 13.

With the collection of particulates,
Although the filter pressure loss of the DPF 13 rises, the control unit 23-1 captures the engine speed N during traveling and simultaneously captures data from each of the pressure sensors 39, 41, and 57.

Incidentally, the pressure sensor 41 may be omitted. In this case, the pressure loss Pa is calculated using a value Pa stored in advance in the calculation formula. Then, the control unit 23-1 calculates the filter pressure loss ΔP from the calculation formula, and obtains the DPF corresponding to the engine speed N and the boost pressure.
It is determined whether or not the filter pressure loss ΔP of No. 13 exceeds the pressure loss threshold value of the pressure loss threshold value map of FIG. 6, and when the calculated filter pressure loss ΔP exceeds the pressure loss threshold value,
Closing the butterfly valve 17 and activating the heater 29,
At the same time, the butterfly valve 19 is opened to allow the exhaust gas to flow down to the branch pipe 9 side.

Therefore, the particulate in the exhaust gas is D
The particulate matter in the DPF 13 is collected by the PF 15, and at this time, the particulate matter in the DPF 13 is burned and removed by the heater 29, so that the DPF 13 is regenerated. Further, as described above, the temperature sensors 49 and 51 are mounted on the heaters 29 and 31, respectively, and the control unit 23-1 sends the temperature sensors 49 and 51 to the heater 29 when the temperature of the heater 29 reaches a predetermined value. Is stopped, and the temperature of the heater 29 is controlled.

Hereinafter, the control unit 23-1 calculates the filter pressure loss ΔP from the calculation formula, and calculates the filter pressure loss ΔP of the DPF 15 according to the engine speed N and the boost pressure.
While determining whether P exceeds the pressure loss threshold value in the pressure loss threshold map of FIG.
15 and the DPF 13 are sequentially performed.

As described above, according to the present embodiment, the boost pressure as an engine load parameter is added to the engine speed N and the filter pressure loss ΔP as shown in FIG. By setting the pressure drop threshold map, the regeneration start timing of the DPFs 13 and 15 is configured to be determined.
DPF13 in the exhaust system of the engine 3-1 with turbo,
Thus, the determination of the reproduction start time can be easily and accurately performed.

As described above, in addition to the above-described boost pressure, the engine load itself may be used as the engine load parameter, or the exhaust temperature may be used as the parameter of the engine load. Therefore, instead of the pressure loss threshold map of FIG. 6, as one embodiment of the third embodiment, a pressure loss threshold map is set based on the engine speed N, the filter pressure loss ΔP and the engine load as shown in FIG. May be stored in the control unit 23-1, and FIG.
As described above, a pressure loss threshold map may be set based on the engine speed N, the filter pressure loss ΔP, and the exhaust gas temperature, and may be stored in the control unit 23-1.

Then, the microcomputer 23-1 is configured to determine the regeneration start timing based on the detection values from the load sensor and the temperature sensor attached to the exhaust system. Similarly, it is possible to achieve the intended purpose.

[0039]

As described above, the regenerating apparatus according to each of the claims makes it possible to determine the DPF regeneration start timing using a simple pressure loss threshold map without obtaining the exhaust gas flow rate with a complicated configuration. Therefore, there is an advantage that the DPF regeneration start timing can be accurately determined while simplifying the configuration of the entire apparatus as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a DPF regeneration device according to an embodiment of the present invention.

FIG. 2 is an embodiment of a pressure loss threshold map.

FIG. 3 is an embodiment of a pressure loss threshold map.

FIG. 4 is a flowchart of a DPF regeneration start determination.

FIG. 5 shows a DP according to an embodiment of claims 2 and 4.
It is a schematic diagram of the reproducing apparatus of F.

FIG. 6 is an embodiment of a pressure loss threshold map.

FIG. 7 is an embodiment of a pressure loss threshold map.

FIG. 8 is an embodiment of a pressure loss threshold map.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust manifold 3,3-1 Engine 5 Exhaust pipe 7,9 Branch pipe 13,15 DPF 17,19,21 Butterfly valve 23,23-1 Control unit 29,31 Heater 35,55 Regeneration device 39,41,57 Pressure Sensor 43 Rotation sensor 45 Engine ECU 49, 51 Temperature sensor 53 Turbocharger 59 Intake manifold

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G084 AA01 BA24 DA04 DA27 EA11 EB08 EB12 FA00 FA01 FA12 FA18 FA23 FA27 3G090 AA04 BA04 CA01 CB22 CB25 DA01 DA03 DA06 DA11 DA12 DA18 DA20 EA05

Claims (5)

[Claims] 1. A pressure sensor for detecting a pressure on an inlet side of a diesel particulate filter mounted on a downstream end side of an exhaust system of a diesel engine, an atmospheric pressure sensor for detecting an atmospheric pressure, and a rotational speed of the diesel engine. A rotation sensor, a filter regeneration unit that burns and removes the particulate matter collected by the diesel particulate filter, and a pressure loss preset based on the engine speed and the filter pressure loss, inputting the detection values of the sensors. Control means for storing a threshold value map, wherein the control means calculates a filter pressure loss from detection values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is a pressure loss threshold value corresponding to the detection value of the rotation sensor. A diesel regeneration unit that activates the filter regeneration means when the pressure loss threshold value of the map is exceeded. Interview filter of the playback device. 2. A pressure sensor for detecting a pressure on an inlet side of a diesel particulate filter mounted on an exhaust system of a diesel engine, an atmospheric pressure sensor for detecting an atmospheric pressure, and a rotation sensor for detecting a rotation speed of the diesel engine. A parameter sensor for detecting a parameter representing an engine load; a filter regeneration means for burning and removing particulates collected by the diesel particulate filter; and a detection value of each of the above sensors, and an engine speed and a filter. Control means for storing a pressure loss threshold map preset based on the pressure loss and the parameters, wherein the control means calculates a filter pressure loss from detection values of the pressure sensor and the atmospheric pressure sensor, and the calculated value is a parameter Pressure loss of pressure loss threshold map according to sensor and rotation sensor detection values When it exceeds had values, diesel particulate filter regeneration and wherein the actuating said filter regeneration means. 3. The regeneration device for a diesel particulate filter according to claim 2, wherein the parameter representing the engine load is the engine load itself. 4. The regeneration device for a diesel particulate filter according to claim 2, wherein the parameter is a boost pressure of the diesel engine. 5. The regeneration device for a diesel particulate filter according to claim 2, wherein the parameter is an exhaust gas temperature of the diesel engine.