JP2004270574A - Exhaust emission control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend period until next regeneration of an exhaust emission control device main body by suppressing use of the exhaust emission control device main body as much as possible while effectively controlling air pollution in an exhaust emission control device for a vehicle. <P>SOLUTION: A determination means determines if an existing position of the vehicle is inside of an exhaust emission control area or outside of the exhaust emission control area. A control means 20 controls operation of a switch means 4 based on determination information from the determination means. If it is determined that the existing position of the vehicle is inside of the exhaust emission control area, exhaust gas flows through a first passage 1a and is purified by the exhaust emission control device body 2. If it is determined that the existing position of the vehicle is outside of the exhaust emission control area, exhaust gas flows through a second passage 1b and is discharged to open air with bypassing the exhaust emission control device body 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification device for a vehicle, in which exhaust gas from an internal combustion engine is purified by an exhaust gas purification device main body, and in particular, it is preferable to use a particulate filter as the exhaust gas purification device main body.
[0002]
[Prior art]
In recent years, there has been an increasing movement to protect the global environment. In particular, air pollution due to the large consumption of fossil fuels has become a serious problem. This is a very important issue.
In particular, as the economy and society develop, a large number of diesel trucks (trucks equipped with diesel engines), which play a leading role in logistics, will gather in major cities such as central Tokyo, Osaka, and Nagoya, which are the center of logistics. Air pollution has become a serious problem.
[0003]
For this reason, a particulate filter has attracted attention as a technique for removing particulate matter (PM) contained in exhaust gas of a diesel engine.
The particulate filter is installed in the exhaust passage, and the PM is collected by the particulate filter in the process of passing the exhaust gas through the particulate filter, and the collected PM is deposited on the particulate filter. If the PM deposits excessively, the particulate filter becomes clogged. Therefore, it is necessary to remove the deposited PM and regenerate the particulate filter so that the PM can be removed.
[0004]
Exhaust gas purifiers using a particulate filter can be classified into a manual regeneration type and an automatic regeneration type according to the regeneration method of the particulate filter.
In the manual regeneration type, the particulate filter is once removed from the vehicle, and an operator heats the particulate filter to incinerate and remove PM, or removes PM by steam cleaning. For this reason, a facility for performing the work (regeneration processing facility) is required, and the vehicle equipped with the particulate filter must go to such a regeneration processing facility each time the particulate filter is regenerated. In addition, the number of such regeneration processing facilities is small at present, and the area where the facilities are located is limited, so that the running of the vehicle is restricted by the regeneration processing of the particulate filter. Large-sized trucks for long-distance transportation are not suitable for mounting such a manual regeneration type particulate filter.
[0005]
As an automatic regeneration type, for example, there is an automatic regeneration type in which an oxidation catalyst is disposed upstream of a particulate filter in an exhaust passage. By converting NO in exhaust gas to NO ₂ having a high oxidizing function by this oxidation catalyst, PM can be burned by the exhaust gas temperature itself, so that the particulate filter can be regenerated continuously and simultaneously with the recovery of PM. become.
[0006]
However, in this type, PM can be burned as described above if the engine load is high and the exhaust temperature is relatively high, but PM cannot be burned if the engine load is low and the exhaust temperature is relatively low. Therefore, the combustion of PM depends on the operating conditions, and the reliability of the regeneration of the particulate filter is low.
In addition, as an automatic regeneration type, in addition, the PM accumulation amount of the particulate filter is detected, and when it is determined that the regeneration process is necessary based on the detected value, the particulate filter is heated by a heater and automatically. Some play. In this form, two particulate filters are provided in parallel and the inflow of exhaust gas into these particulate filters can be selectively switched, so that one of the particulate filters in use (during the inflow of exhaust gas) If it is determined that the regeneration is necessary, the flow of exhaust gas is switched to the other particulate filter, and then the regeneration of the one particulate filter is performed. Thereafter, such switching is continuously performed ( That is, the particulate filters are used alternately).
[0007]
However, in this type, it is difficult to accurately detect the amount of deposited PM and to adjust heating for the particulate filter regeneration process, and the durability of the particulate filter is not very high. On the other hand, there is a possibility that the particulate filter is excessively heated and the particulate filter is damaged. As described above, the automatic regeneration type is still low in reliability for practical use, and at present, very few have an automatic regeneration type particulate filter.
Thus, in the use of the particulate filter, the reproduction process is a bottleneck.
[0008]
In view of this, Patent Document 1 discloses an exhaust gas purifying apparatus capable of minimizing the frequency of a particulate filter regeneration process. In this device, the exhaust pipe is branched into a first conduit in which a particulate filter is installed and a second conduit (bypass passage) for bypassing exhaust gas to the particulate filter. Then, based on the detection information of the engine state detecting means, it is determined whether or not the current operating state is an operating state in which the exhaust contains a large amount of particulate matter (PM). While flowing through the conduit to collect PM by the particulate filter, in an operation state with a small amount of PM, exhaust gas is flowed through the second conduit to bypass the particulate filter.
[0009]
When the PM concentration of the exhaust gas discharged from the engine is low and it is not necessary to remove the PM, the use of the particulate filter is suppressed as much as possible by bypassing the exhaust gas with the particulate filter, and the frequency of the regeneration process is reduced as much as possible. It is possible to control.
[0010]
[Patent Document 1]
JP-A-8-303230
[Problems to be solved by the invention]
However, there is still a strong demand to suppress the use of the particulate filter as much as possible and to suppress the frequency of the regeneration processing as much as possible, and it is conceivable to suppress the use frequency of the particulate filter by focusing on a point different from the PM concentration of the exhaust gas. .
[0012]
For example, in suburban areas where the regulation of air pollution is not so strict (that is, the degree of air pollution is relatively low), exhaust gas is directly discharged to the atmosphere without using a particulate filter, and the regulation of air pollution is strict (ie, In an urban area or the like where the degree of air pollution is relatively high, the exhaust gas may be purified using a particulate filter and then released to the atmosphere.
[0013]
As a result, the frequency of regeneration of the particulate filter can be suppressed while preventing air pollution particularly in an urban area where the situation is serious.
As described above, in order to switch the use of the particulate filter depending on the area, (1) When the driver enters an area where exhaust purification is preferably performed by the particulate filter (exhaust purification area) such as an urban area, the driver voluntarily manually operates. In addition to the above, for example, (2) means for automatically switching the driving mode by determining that the vehicle is in an exhaust gas purification area such as an urban area when the vehicle speed becomes lower than a predetermined value, or (3) Purifying exhaust gas such as a beacon in an urban area A means for transmitting a message indicating that the area is in place may be provided, and upon receiving this signal, means for switching the use of the particulate filter may be considered.
[0014]
However, it is not always reliable to judge whether or not the driver has entered an exhaust purification area such as an urban area. It is not always the case that the use is switched to the filter.
Further, it is not practical to determine an exhaust gas purification area such as an urban area based on the vehicle speed because the determination system is poor.
[0015]
In addition, installing a beacon or the like in an urban area is costly, and only local information near the beacon can be obtained. Therefore, it is necessary to wait for a high density of beacons to be installed in all exhaust purification areas. If this is not the case, this is not possible.
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is possible to suppress the use of an exhaust purification device main body (particulate filter) as much as possible while effectively suppressing air pollution. It is an object of the present invention to provide a vehicle exhaust purification device capable of extending a period until the next regeneration of the vehicle.
[0016]
[Means for Solving the Problems]
Therefore, in the vehicle exhaust emission control device according to the first aspect of the present invention, based on the information from the position measurement unit and the storage unit, the determination unit determines that the current position of the vehicle is within a preset exhaust emission control region. It is determined whether or not there is, and the control means controls the operation of the switching means based on the determination information from the determination means.
[0017]
Accordingly, when it is determined that the current position of the vehicle is within the exhaust purification area, the exhaust gas flows through the first passage and is purified by the exhaust purification device main body, while the current position of the vehicle is outside the exhaust purification area. Is determined, the exhaust gas flows through the second passage and is discharged to the atmosphere bypassing the exhaust gas purification device main body.
[0018]
In the exhaust gas purifying apparatus for a vehicle according to the present invention, the exhaust gas purifying device main body is a particulate filter, and PM is removed from the exhaust gas when passing through the particulate filter.
In the exhaust gas purifying apparatus for a vehicle according to the third aspect of the present invention, the regeneration process is performed after the particulate filter is removed from the first passage.
According to a fourth aspect of the present invention, the particulate filter is regenerated in a state where the particulate filter is mounted on the vehicle.
As a particulate filter that performs regeneration while mounted on a vehicle, a heater that operates using an external power supply is provided facing the particulate filter. By operating this heater using an external power supply while the vehicle is stopped, the deposited PM can be heated and removed with the particulate filter mounted on the vehicle.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 are views showing a vehicle exhaust purification device as an embodiment of the present invention.
As shown in FIG. 1, in the present exhaust gas purification device, an exhaust passage 1 for guiding exhaust gas from a diesel engine (internal combustion engine) not shown is provided with a first passage 1 a in which a particulate filter (exhaust gas purification device main body) 2 is installed. , And a second passage 1b in which the muffler 3 is installed.
[0020]
The particulate filter 2 is a ceramic honeycomb filter having relatively fine eyes, and is configured to capture PM in the exhaust gas passing therethrough. Further, here, the particulate filter 2 is configured to be removable from the exhaust passage, and the regeneration process is performed by a manual operation of an operator after being removed from the vehicle body. Further, the reproduction processing may be automatically performed using a reproduction processing device.
[0021]
Switching valves 4a and 4b are provided upstream of the particulate filter 2 in the first passage 1a and upstream of the muffler 3 in the second passage 1b, respectively. An air cylinder 4c is connected to each of these switching valves 4a and 4b, and by controlling the operation of the solenoid valve 4d, the air supply from the air tank 4e is switched to either the switching valve 4a side or the switching valve 4b side. One of the switching valves 4a and 4b is selectively switched over.
[0022]
When the switching valve 4a is opened and the switching valve 4b is closed, the exhaust gas from the exhaust passage 1 flows into the first passage 1a, and the particulate filter 2 removes the PM in the exhaust gas. It is configured to be collected (hereinafter, this operation mode is referred to as PM collection mode). In this case, the exhaust noise is suppressed by the particulate filter 2 instead of the muffler 3.
[0023]
Conversely, when the switching valve 4a is closed and the switching valve 4b is opened, the exhaust gas flows through the second passage 1b and is discharged to the atmosphere while the exhaust noise is suppressed by the muffler. The air is discharged to the atmosphere by bypassing the curable filter 2 (hereinafter, this operation mode is referred to as a filter bypass mode).
Thus, the switching means 4 of the present invention is constituted by the switching valves 4a, 4b, the air cylinders 4c, 4c, the solenoid valve 4d, and the air tank 4e.
[0024]
The exhaust emission control device includes a control unit (ECU) 20 and a navigation system 11. The selection between the PM collection mode and the filter bypass mode is performed based on information from the navigation system 11. The ECU 20 controls the operation of the switching valves 4a and 4b (more specifically, the operation of the solenoid valve 4d).
[0025]
Hereinafter, this control will be described in detail. The navigation system 11 includes an information processing portion (not shown) for measuring the position (current position) of the vehicle, and a map (not shown) displaying the map of the travel area of the vehicle and the position of the own vehicle on the map. ing.
In the information processing part, in addition to the function as the position measuring means, a judgment is made based on the information from the position measuring means and the information on the exhaust purification area to determine whether or not the current vehicle position is in the exhaust purification area. A function as a means is added. Examples of the exhaust gas purification area include an urban area of a large city where air pollution is extremely severe, and an area such as a hospital or a school or the like where environmental protection is particularly required.
[0026]
In the navigation system 11, the position of the vehicle is measured by combining the radio navigation and the map matching method.
Here, as the radio navigation, a GPS (Global Positioning System) 12 is used. The GPS 12 includes a plurality of satellites (Nabster satellites) 12A and a terrestrial system (not shown) that sends necessary signals to the satellites 12A and manages the signals, and the like. The signals are caught and input to the navigation system 11 via an amplifier and a receiver 14 (not shown).
[0027]
The navigation system 11 can detect the position of the vehicle, that is, the longitude and the latitude, based on the radio wave from the satellite 12A input as described above.
The map matching method focuses on the fact that a vehicle travels on a normal road in principle, and can correct a measurement error of the position of the vehicle by matching a traveling locus of the vehicle with a road shape. Here, the vehicle's travel locus is obtained by following the position of the vehicle obtained with the information from the satellite 12A with the passage of time, and the travel locus is matched with the road shape to obtain the vehicle position obtained by radio navigation. Correct the error of.
[0028]
The navigation system 11 is connected to a storage means (for example, a CD-ROM or a DVD-ROM) 15 for storing a map of a desired area for displaying a map on the display, and this is used for map matching. It is also used for
The storage means 15 also stores, in addition to the map information, information relating to the exhaust gas purification areas (zero emission zones and areas with severe air pollution) in the map. It is determined whether or not the current position of the vehicle obtained and obtained by the map matching corresponds to the exhaust purification area given from the storage means 15. The ECU 20 outputs a signal for causing the ECU 20 to operate in the filter bypass mode when the signal does not correspond to the exhaust gas purification area.
[0029]
The exhaust gas purification apparatus as one embodiment of the present invention is configured as described above, and the control is performed as shown in the flowchart of FIG.
That is, after the current position of the vehicle is detected in step A10, it is determined in step A20 whether the current position corresponds to an exhaust gas purification area. If it is determined that the current position corresponds to the exhaust purification area, the process proceeds to step A30, and the operation in the PM collection mode is performed. If it is determined that the current position does not correspond to the exhaust purification area, Then, the process proceeds to Step A40, and the operation in the filter bypass mode is performed.
[0030]
Then, after the operation mode is selected as described above, the process returns to step A10, and such control is repeated.
In this way, the present exhaust gas purifying apparatus performs traveling in the PM collection mode in an exhaust gas purification area where air pollution is severe or in an exhaust gas purification area where environmental protection is required, while receiving information from the GSP 12. Thus, air pollution is prevented, and in other areas (general areas), use of the particulate filter is avoided by traveling in the filter bypass mode.
[0031]
This makes it possible to extend the period until the particulate filter 2 is regenerated while effectively preventing air pollution. Since the particulate filter 2 of the present embodiment is of a manual regeneration type, it is necessary to go to a predetermined facility in order to regenerate (or replace) the particulate filter 2, and the vehicle equipped with the particulate filter travels during this regeneration operation. However, in the present exhaust emission control device, the period until the particulate filter 2 is replaced can be extended as described above, so that such a constraint can be greatly suppressed and long-distance transportation can be performed. It can also be used for large trucks.
[0032]
If the regeneration of the particulate filter is insufficient, PM will be excessively deposited on the particulate filter in the subsequent operation. There is a possibility that the particulate filter may be ignited by being exposed to the high-temperature exhaust gas and may be melted. On the other hand, in the present exhaust gas purification apparatus, since the regeneration of the particulate filter 2 is performed manually by an operator while monitoring the state of the particulate filter 2, PM can be removed more reliably than in the automatic regeneration type. (The reliability of the process is high), and it is possible to prevent the particulate filter from being melted during such operation.
[0033]
As a method of automatically regenerating the particulate filter, there is a method in which a heater is provided in an exhaust passage and the particulate filter is heated and regenerated by the heater. However, the amount of heating of the particulate filter is determined by the PM of the particulate filter. Unless it is adjusted accurately according to the amount of deposition, the particulate filter may be eroded. On the other hand, in the manual regeneration type, the particulate filter can be regenerated by removing the PM by steam cleaning, and thus the melting loss associated with such regeneration can be prevented.
[0034]
Further, in the exhaust gas purifying apparatus of the manual regeneration type, components for performing the regeneration treatment (for example, a heater and an oxidation catalyst) become unnecessary, so that the production cost can be reduced as compared with the automatic regeneration type.
[0035]
The vehicle exhaust purification device of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
For example, after returning the vehicle to a garage or the like, a regeneration process can be performed by operating a heater using an external power supply of 200 V while the particulate filter is attached to the vehicle (that is, while the vehicle is at a standstill, the external filter may be activated) (A format in which the reproduction process can be performed using a power supply).
Further, in the above embodiment, the exhaust purification device is of a manual regeneration type, but may be of an automatic regeneration type in which an oxidation catalyst is arranged on the upstream side of a particulate filter as described in the related art, for example. It is. Even in this case, since the particulate filter can be used efficiently, the life of the particulate filter can be extended.
[0036]
Further, in the above embodiment, when the vehicle is in the exhaust purification area, the traveling mode is set to the PM collection mode while the vehicle is in the exhaust purification area. The driving mode may be the filter bypass mode even in the area. Whether or not the operating state is such that the PM concentration of the exhaust gas is relatively low can be determined based on, for example, the lubricating oil temperature and the engine speed.
[0037]
Further, the means for measuring the current position of the vehicle may be ITS (Intelligent Transport System).
Furthermore, in the above-described embodiment, an example was described in which a particulate filter was used as the exhaust gas purification device main body. However, the exhaust gas purification device main body may be any device that purifies the passing exhaust gas, such as a NOx catalyst.
[0038]
【The invention's effect】
As described in detail above, according to the vehicle exhaust purification device of the first aspect, storage means for storing information on the exhaust purification area, position measurement means for measuring the current position of the vehicle, position measurement means and storage Determining means for determining whether or not the current position of the vehicle is within the exhaust purification area, based on information from the means; and When the determination information is received, the operation of the switching means is controlled so that exhaust gas flows through the first passage provided with the exhaust gas purification device main body, while the current position of the vehicle is outside the exhaust purification area from the determination means. When the determination information is received, the operation of the switching means is controlled such that the exhaust gas bypasses the exhaust gas purification device main body and flows through the second passage. Use of the body Suppressing force can expand the period until the reproduction of the next exhaust gas purifier body.
[0039]
The exhaust gas purification device main body is, for example, a particulate filter.
When the particulate filter is configured to be detachable from the first passage, and the particulate filter is regenerated after the removal, the period until the next regenerating process can be extended as compared with the related art. Therefore, the restriction on the traveling distance associated with the filter can be reduced, and the particulate filter can be reproduced with high reliability.
[0040]
On the other hand, if the particulate filter is of a type in which regeneration processing is performed in a state of being mounted on the vehicle, removal of the particulate filter from the vehicle is not required, and work related to the regeneration processing can be simplified.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a vehicle exhaust purification device as one embodiment of the present invention.
FIG. 2 is a schematic flow chart for explaining control contents of a vehicle exhaust purification device as one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exhaust passage 1a First passage 1b Second passage 2 Particulate filter (exhaust gas purifier main body)
3 Muffler 4 Switching means 11 Navigation system (position measurement means, judgment means)
15 storage means 20 ECU (control means)

Claims (4)

An exhaust passage, which is mounted on the vehicle and guides exhaust gas from the internal combustion engine, is branched into a first passage having an exhaust gas purification device main body and a second passage for bypassing the exhaust gas purification device main body, and the exhaust gas is circulated through the second passage. A vehicle exhaust purification device comprising: switching means for switching to one of the first passage and the second passage; and control means for controlling operation of the switching means.
Storage means for storing information of an exhaust gas purification area for purifying the exhaust gas by the exhaust gas purification device main body;
Position measuring means for measuring the current position of the vehicle,
Determining means for determining whether or not the current position of the vehicle is within the exhaust gas purification area based on the information from the position measuring means and the storage means;
The control means includes:
When receiving the determination information that the current position of the vehicle is within the exhaust gas purification area from the determination means, the controller controls the operation of the switching means so that the exhaust gas flows through the first passage.
When receiving the determination information that the current position of the vehicle is outside the exhaust gas purification area from the determination means, the operation of the switching means is controlled so that the exhaust gas flows through the second passage. , Vehicle exhaust purification system. The exhaust gas purifying apparatus for a vehicle according to claim 1, wherein the exhaust gas purifying apparatus main body is a particulate filter. 3. The exhaust gas purifying apparatus for a vehicle according to claim 2, wherein the particulate filter is configured to be detachable from the first passage, and is configured to perform a regeneration process after the removal. 3. The exhaust gas purifying apparatus for a vehicle according to claim 2, wherein the particulate filter is of a type that is subjected to a regeneration process when the particulate filter is mounted on the vehicle.

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