JPH0949419A - Particulate disposal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the exhaust gas temperature by mixing high pressure air or the like as cooling gas into high temperature exhaust gas in the case of a vehicle being stopped during the regeneration of a trap filter. SOLUTION: An air lead-in passage 4 for leading in air, pressurized by an air compressor 7, through an air reservoir tank 3 is opened to an exhaust passage 1b downstream of a particulate disposal device 2. A throttle valve 5 for regulating the lead-in flow quantity of the compressed air is disposed at the air lead-in passage 4. During the regeneration of a trap filter, a control unit 6 judges whether or not a vehicle is stopped on the basis of the detection signals of a vehicle speed sensor 9 and a rotating speed sensor 10, and when the vehicle is stopped, the opening/closing of the throttle valve 5 and its opening degree are controlled while performing feedback control for maintaining the exhaust gas temperature to the allowable value or less on the basis of the detection signal of an exhaust gas temperature sensor 13, thus lowering the exhaust gas temperature efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particulate treatment device for treating particulates discharged from a diesel engine or the like, and more particularly to a technique for reducing the temperature of exhaust gas discharged during trap filter regeneration processing.

[0002]

2. Description of the Related Art Conventionally, as an exhaust gas purifying apparatus for a diesel engine or the like, in order to reduce particulates (exhaust particulates) in exhaust gas, a particulate processing apparatus having a trap filter for trapping particulates in an exhaust passage. There is something that has been inserted. In such a particulate treatment device, when the collected particulates increase, the exhaust pressure rises due to the clogging of the trap filter and the engine performance deteriorates.Therefore, heating of a burner or the like in the exhaust passage on the upstream side of the trap filter occurs. The trap filter is regenerated by arranging a means for burning and removing the collected particulates (Japanese Utility Model Laid-Open No. 1-75703, Japanese Utility Model Laid-Open No. 3-87911 and Japanese Utility Model Laid-Open No. 7-8520). (See gazette, etc.).

[0003]

However, when the trap filter is regenerated, in the regeneration system in which the trapped particulates are burned and removed by a burner or the like, the exhaust gas temperature becomes relatively high, and therefore the trap is trapped. During the filter regeneration process, if the vehicle is stopped due to, for example, a signal waiting or a traffic jam, high-temperature exhaust gas is discharged from the tail pipe, and a pedestrian or the like passing by the tail pipe may feel uncomfortable.

In view of the conventional problems as described above, the present invention mixes high-temperature exhaust gas with high-pressure air as cooling gas when the vehicle stops during the regeneration process of the trap filter. The purpose is to lower the exhaust gas temperature.

[0005]

Therefore, according to the first aspect of the present invention, a trap filter for trapping particulates is provided in the exhaust passage of the internal combustion engine, and the trapped particulates are burned and removed. In the particulate treatment device having the regeneration means for regenerating the trap filter, the vehicle stop detection means for detecting the vehicle stop, the temperature detection means for detecting the exhaust gas temperature discharged from the vehicle, and the downstream of the trap filter. Cooling gas introduction means for introducing cooling gas into the exhaust passage on the side, and when the vehicle stop is detected by the vehicle stop detection means during operation of the regeneration means, based on the exhaust gas temperature detected by the temperature detection means, And a control means for controlling the cooling gas introduction means.

According to a second aspect of the present invention, the cooling gas introducing means is an air pressurizing means for supplying high pressure air as a cooling gas, an air storing means for storing the high pressure air, and the stored high pressure air is exhausted. The air introduction passage introduced into the passage and the throttle valve for changing the flow passage cross-sectional area of the air introduction passage are included. According to a third aspect of the present invention, the cooling gas introducing means includes an outside air intake means for taking in outside air as the cooling gas, and an outside air introducing passage for introducing the introduced outside air into the exhaust passage.

According to a fourth aspect of the present invention, the cooling gas introducing means connects the exhaust passages on the upstream side and the downstream side of the particulate processing apparatus to each other so that the exhaust gas on the upstream side as the cooling gas is placed on the downstream side. A bypass passage introduced into the exhaust passage and a throttle valve for changing the flow passage cross-sectional area of the bypass passage are included.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a particulate processing apparatus according to the present invention. First,
The configuration of a basic particulate processing device will be described.
In the exhaust passages 1a and 1b for guiding the exhaust gas from the engine (not shown) to the tail pipe, a particulate treatment device 2 for collecting particulates in the exhaust gas is interposed in the middle thereof. The particulate treatment device 2 has a trap filter (not shown) made of ceramic or the like housed therein, and the trap filter collects the particulates and reduces the particulates of the exhaust gas discharged outside the vehicle. Has been realized.
A burner or the like (not shown) for burning and removing particulates is provided in the exhaust passage 1a on the upstream side of the trap filter for the purpose of removing the particulates accumulated on the trap filter, that is, for the regeneration processing of the trap filter. There is.

Further, as a peculiar structure according to the invention described in claim 2, by discharging the compressed air into the exhaust passage 1b on the downstream side of the particulate processing apparatus 2, the high temperature discharged during the regeneration processing of the trap filter. In order to reduce the temperature of the exhaust gas, the air introduction passage 4 for introducing the compressed air stored in the air reservoir tank 3 (air storage means) into the exhaust passage 1b is opened. A throttle valve 5 for adjusting the flow rate of the compressed air introduced is disposed in the middle of the air introduction passage 4, and its opening / closing and opening degree control are performed by a drive signal of a control unit 6 described later. In addition, compressed air pressurized by an air compressor 7 (air pressurizing means) is supplied to the air reservoir tank 3 via a check valve 8. The air compressor 7, the air reservoir tank 3, the air introducing passage 4, and the throttle valve 5 constitute the cooling gas introducing means.

The sensors used to control the particulate processing apparatus include a vehicle speed sensor 9 (vehicle stop detecting means) for detecting the vehicle speed, a rotation speed sensor 10 (vehicle stop detecting means) for detecting the engine speed, and a particulate processing apparatus. 2, an exhaust pressure sensor 11 for detecting the exhaust gas pressure on the upstream side of a trap filter (not shown), and an air pressure sensor 12 for detecting the air pressure of the air reservoir tank 3.
Further, an exhaust temperature sensor 13 (temperature detecting means) for detecting the exhaust temperature on the downstream side of the air introduction passage 4 opened to the exhaust passage 1b is provided.

The signals of the vehicle speed sensor 9, the rotation speed sensor 10, the exhaust pressure sensor 11, the air pressure sensor 12 and the exhaust temperature sensor 13 are input to the control unit 6 which is a microcomputer. The control unit 6 determines the control contents of the air compressor 7 and the throttle valve 5 based on the input signal, and outputs the drive signals to the air compressor 7 and the throttle valve 5, respectively. In addition,
The control unit 6 has a function as control means of the present invention.

Next, the control contents of the particulate processing apparatus described above will be described in detail with reference to the flowchart of FIG. In step 1 (abbreviated as S1 in the figure. The same applies hereinafter), the air pressure p detected by the air pressure sensor 12 is a predetermined pressure p1 (for example, 50 kPa).
It is determined whether or not the following. Then, if p ≦ p1, the process proceeds to step 2, and if p> p1, the process proceeds to step 3.

In step 2, since it is determined that the air pressure of the compressed air stored in the air reservoir tank 3 has fallen below the lower limit of the specified value, the air compressor 7 is operated. In step 3, it is determined whether the air pressure p is equal to or higher than a predetermined pressure p2 (for example, 90 kPa). Then, if p ≧ p2, the process proceeds to step 4, and if p <p2, the process proceeds to step 5.

In step 4, since it is judged that the air pressure of the compressed air stored in the air reservoir tank 3 has reached the upper limit of the specified value, the air compressor 7 is stopped. That is, in the processing of steps 1 to 4 described above,
The compressed air in the air reservoir tank 3 is within the specified range p1 ≦ p <
p2 (for example, 50 kPa to 90 kPa).

At step 5, it is judged whether or not a trap filter regeneration processing request is issued (regeneration processing is being performed). In principle, the regeneration process is performed every predetermined time (for example, every two hours), but when it can be determined that the pressure loss is occurring based on the exhaust pressure detected by the exhaust pressure sensor 11, The reproduction process is performed even before the elapse of a predetermined time. Then, if the reproduction processing request is not generated, the process returns to step 1, and if the reproduction processing request is generated, the process proceeds to step 6.

At step 6, it is judged whether or not the trap filter regeneration processing is completed. That is, since the reproduction process is continuously performed for a predetermined time (for example, 10 minutes) after the start, it is determined whether the predetermined time has elapsed from the start of the reproduction process. If the predetermined time has elapsed (reproduction processing end), the process proceeds to step 7. If the predetermined time has not elapsed (reproduction process continues), the process proceeds to step 8.

In step 7, since the regeneration process is completed, the throttle valve 5 is fully closed as an end process, and the process returns to step 1. In step 8, it is determined whether or not the vehicle is stopped based on the vehicle speed V and the rotation speed N detected by the vehicle speed sensor 9 and the rotation speed sensor 10. That is, if the vehicle speed V = 0 and the rotation speed N ≠ 0, it can be determined that the vehicle is stopped (for example, waiting for a signal) while the engine is operating. If the vehicle is stopped, the process proceeds to step 9, and if the vehicle is not stopped, the process proceeds to step 7. Here, when it is determined that the vehicle is not stopped, it is not necessary to reduce the exhaust gas temperature, which is the object of the present invention (while running, pedestrians cannot pass near the tail pipe of the vehicle. Therefore, in step 7, the throttle valve 5 is fully closed and the process returns to step 1.

In step 9, it is judged whether or not the exhaust temperature t detected by the exhaust temperature sensor 13 is equal to or higher than a predetermined allowable temperature t1 (for example, 150 ° C.). And t
If ≧ t1, the process proceeds to step 10, and if t <t1, the process proceeds to step 11. In step 10, since the temperature t of the exhaust gas is equal to or higher than the allowable temperature t1, the opening degree of the throttle valve 5 is increased so that the temperature of the exhaust gas is lowered. Then, the process returns to step 1.

In step 11, since the temperature t of the exhaust gas is lower than the allowable temperature t1, the opening degree of the throttle valve 5 is reduced to prevent wasteful consumption of compressed air, and the process returns to step 1. That is, in the processing of steps 9 to 11, optimal feedback control is performed to make the temperature of exhaust gas discharged from the vehicle equal to or lower than the predetermined temperature t1.

According to the first embodiment described above, when the vehicle is stopped during the trap filter regeneration process,
The temperature of the exhaust gas discharged from the tail pipe of the vehicle is reduced because the compressed air stored in the air reservoir tank is efficiently introduced (mixed) into the hot exhaust gas by detecting the stoppage of the vehicle by feedback control. You can Moreover, since the compressed air from the air compressor is not directly introduced but is introduced through the air reservoir tank, there is a margin in the air capacity, and the response of the introduction of the compressed air can be improved.

FIG. 3 shows a second embodiment of the particulate processing apparatus according to the present invention. In the second embodiment, the basic structure of the particulate processing apparatus is the same as that of the first embodiment described above, and therefore, the same reference numerals are given and the description thereof is omitted here, and only different structures will be described. To do. As a peculiar structure of the third aspect of the invention, an outside air introduction passage 15 for taking in outside air by a blower 14 (outside air intake means) is opened in the exhaust passage 1b on the downstream side of the particulate treatment device 2. This outside air introduction passage 15
A check valve 16 is interposed in the exhaust passage 1b so that the exhaust gas does not flow backward. The blower 14 and the outside air intake passage 15 constitute the cooling gas introducing means according to the first aspect.

The sensors used to control the particulate processing apparatus are a vehicle speed sensor 9 and a rotation speed sensor 1.
0, an exhaust pressure sensor 11, and an exhaust temperature sensor 13 are provided, and these respective signals are input to the control unit 6, respectively. The control unit 6 determines the control content of the blower 14 based on the input signal,
The drive signal is output to the blower 14.

Next, the control contents of the particulate processing apparatus described above will be described in detail with reference to the flowchart of FIG. This routine is called when a trap filter regeneration processing request is issued. Since this regeneration processing request is the same as step 5 in FIG. 1, its explanation is omitted here. Further, the same processing as that in FIG. 2 will be briefly described here.

In step 20, it is judged whether or not the trap filter regeneration process is completed. If the regeneration process is completed, the process proceeds to step 21. If the regeneration process is not completed, the process proceeds to step 22. In step 21, since the trap filter regeneration processing is completed, the blower 14 is stopped and this routine is completed.

In step 22, it is judged whether or not the vehicle is stopped (V = 0 and N ≠ 0) based on the vehicle speed V and the rotation speed N detected by the vehicle speed sensor 9 and the rotation speed sensor 10, and if it is stopped. Proceed to step 23, and if not stopped, proceed to step 26. In step 23, it is judged whether the exhaust temperature t detected by the exhaust temperature sensor 13 is equal to or higher than a predetermined allowable temperature t1 (for example, 150 ° C.), and t ≧
If t1, the process proceeds to step 24, and if t <t1, the process proceeds to step 25.

In step 24, since the temperature t of the exhaust gas is equal to or higher than the allowable temperature t1, the discharge amount of the blower 14 is increased so that the temperature of the exhaust gas is lowered.
Return to. In step 25, the temperature t of the exhaust gas is lower than the allowable temperature t1, so the discharge amount of the blower 14 is reduced, and the process returns to step 20.

Since it is determined in step 26 that the vehicle is not stopped, it is not necessary to lower the exhaust gas temperature which is the object of the present invention. Therefore, the blower 14 is stopped, and step 20
Return to. According to the second embodiment described above, when the vehicle stops during the regeneration process of the trap filter, the stop is detected, and the outside air introduced by the blower into the hot exhaust gas is efficiently introduced by the feedback control ( Therefore, the temperature of the exhaust gas discharged from the tail pipe of the vehicle can be lowered with a simpler structure than the first embodiment described above.

FIG. 5 shows a third embodiment of the particulate processing apparatus according to the present invention. In the third embodiment, the basic structure of the particulate processing apparatus is the same as that of the first embodiment described above, and therefore, the same reference numerals are given and the description thereof is omitted here, and only different structures will be described. To do. As a peculiar structure of the invention according to claim 4, the upstream side exhaust passage 1a and the downstream side exhaust passage 1b of the particulate processing apparatus 2 are communicated with each other, and the upstream side exhaust gas is brought into communication with the downstream side exhaust passage 1b. A bypass passage 17 for introducing the bypass passage 17 is provided, and an inlet of the bypass passage 17 (exhaust passage 1
A throttle valve 18 for changing the flow passage cross-sectional area is arranged in the vicinity of a and a branch portion of the bypass passage 17. The bypass passage 17 and the throttle valve 18 constitute the cooling gas introducing means according to the first aspect.

The sensors used to control the particulate processing apparatus are a vehicle speed sensor 9 and a rotation speed sensor 1.
0, an exhaust pressure sensor 11, and an exhaust temperature sensor 13 are provided, and these respective signals are input to the control unit 6, respectively. The control unit 6 determines the control content of the throttle valve 18 based on the input signal,
The drive signal is output to the throttle valve 18.

Next, the control contents of the particulate processing apparatus described above will be described in detail with reference to the flowchart of FIG. This routine is called when a trap filter regeneration processing request is issued. Since this regeneration processing request is the same as step 5 in FIG. 1, its explanation is omitted here. Further, the same processing as that in FIG. 2 will be briefly described here.

In step 30, it is judged whether or not the trap filter regeneration process is completed. If the regeneration process is completed, the process proceeds to step 31. If the regeneration process is not completed, the process proceeds to step 32. In step 31, since the trap filter regeneration processing is completed, the throttle valve 18 is fully closed and the present routine is completed.

In step 32, it is judged whether the vehicle is stopped (V = 0 and N ≠ 0) based on the vehicle speed V and the rotation speed N detected by the vehicle speed sensor 9 and the rotation speed sensor 10, and if it is stopped. Proceed to step 33, and if not stopped, proceed to step 36. In step 33, it is judged whether the exhaust gas temperature t detected by the exhaust gas temperature sensor 13 is equal to or higher than a predetermined allowable temperature t1 (for example, 150 ° C.), and t ≧
If t1, the process proceeds to step 34, and if t <t1, the process proceeds to step 35.

In step 34, since the temperature t of the exhaust gas is the allowable temperature t1 or higher, the opening degree of the throttle valve 18 is increased,
The temperature of the exhaust gas is lowered, and the process returns to step 30. In step 35, since the temperature t of the exhaust gas is lower than the allowable temperature t1, the opening degree of the throttle valve 18 is reduced and the process returns to step 30.

Since it is determined in step 36 that the vehicle is not stopped, it is not necessary to lower the exhaust gas temperature, which is the object of the present invention, so the throttle valve 18 is fully closed and step 3
Return to 0. According to the third embodiment described above, when the vehicle is stopped during the regeneration process of the trap filter,
The stopped vehicle is detected and the hot exhaust gas is stopped. The exhaust gas that is stopped (the exhaust gas that is stopped does not need to pass through the trap filter because the amount of particulates is very small, and
The temperature is about 90 ° C. ) Is efficiently introduced (mixed) by feedback control, the temperature of the exhaust gas discharged from the tail pipe of the vehicle can be lowered with a simpler configuration than the first and second embodiments described above. it can.

[0035]

As described above, according to the first aspect of the present invention, when the vehicle stops during the regeneration process of the trap filter, the stop is detected and the feedback control of the cooling gas to the hot exhaust gas is performed. The temperature of the exhaust gas discharged from the tail pipe of the vehicle is lowered, so that, for example, a pedestrian passing near the tail pipe of the vehicle does not feel uncomfortable.

According to the second aspect of the present invention, since the high pressure air stored in the air storing means is used as the cooling gas, the high pressure exhaust gas can be efficiently mixed with the high pressure air.
It is possible to reduce the temperature of the exhaust gas discharged from the tail pipe of the vehicle. Further, since the high pressure air as the cooling gas is not directly introduced from the air pressurizing means but is introduced via the air storing means, the capacity of the high pressure air can be increased and the response of the high pressure air introduction can be improved. Can be planned.

According to the third aspect of the present invention, since the outside air taken in by the outside air intake means is used as the cooling gas, the temperature of the exhaust gas at a high temperature can be kept higher than that of the invention according to the second aspect. Can be lowered. Claim 4
According to the invention described in the above, since the exhaust gas in a stopped state is used as the cooling gas, the temperature of the exhaust gas at a high temperature can be lowered with a simpler configuration as compared with the invention according to claim 2 or 3. Cost increase can be suppressed as much as possible.

[Brief description of drawings]

FIG. 1 is a system diagram showing a first embodiment of a particulate processing apparatus according to the present invention.

FIG. 2 is a flowchart showing the control contents of the above.

FIG. 3 is a system diagram showing a second embodiment of the particulate processing apparatus according to the present invention.

FIG. 4 is a flowchart showing the control contents of the above.

FIG. 5 is a system diagram showing a third embodiment of the particulate processing apparatus according to the present invention.

FIG. 6 is a flowchart showing the control contents of the above.

[Explanation of symbols]

 1a, 1b Exhaust passage 2 Particulate processor 3 Air reservoir tank 4 Air introduction passage 5 Throttle valve 6 Control unit 7 Air compressor 9 Vehicle speed sensor 10 Rotation speed sensor 13 Exhaust temperature sensor 14 Blower 15 Outside air introduction passage 17 Bypass passage 18 Throttle valve

Claims (4)

[Claims] 1. A particulate treatment having a trap filter for trapping particulates in an exhaust passage of an internal combustion engine, and a regeneration means for regenerating the trap filter by burning and removing the trapped particulates. In the device, vehicle stop detection means for detecting vehicle stop, temperature detection means for detecting exhaust gas temperature discharged from the vehicle, and cooling gas introduction means for introducing cooling gas into the exhaust passage on the downstream side of the trap filter. A control means for controlling the cooling gas introducing means based on the exhaust gas temperature detected by the temperature detecting means when the stop detecting means detects a stop during the operation of the regeneration means. A particulate treatment device characterized by being processed. 2. The cooling gas introducing means is an air pressurizing means for supplying high pressure air as a cooling gas, an air storing means for storing the high pressure air, and an air introducing means for introducing the stored high pressure air into an exhaust passage. The particulate treatment device according to claim 1, comprising a passage and a throttle valve that changes a flow passage cross-sectional area of the air introduction passage. 3. The cooling gas introducing means includes an outside air intake means for taking in outside air as a cooling gas, and an outside air introducing passage for introducing the introduced outside air into an exhaust passage. The particulate processing apparatus according to claim 1. 4. The bypass for introducing the cooling gas introducing means into the exhaust passages on the upstream side and the downstream side of the particulate processing apparatus, and introducing the exhaust gas on the upstream side as a cooling gas into the exhaust passage on the downstream side. The particulate treatment device according to claim 1, comprising a passage and a throttle valve that changes a flow passage cross-sectional area of the bypass passage.