JP2514606Y2 - Soot removal device in exhaust gas - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a soot removing device for exhaust gas that collects soot contained in exhaust gas of a diesel engine or the like with a filter and incinerates it.

[Prior Art] In the exhaust gas of a diesel engine, exhaust particulates (soot) whose main component is carbon produced by combustion
Is contained in high concentration, which causes pollution. Therefore, the exhaust system of a vehicle equipped with a diesel engine is provided with an exhaust gas purification device that collects soot in exhaust gas with a filter.

In recent years, in order to prevent the filter from being clogged, compressed air (backwash air) is applied to the filter in the direction opposite to the flow of exhaust gas to separate and drop soot from the filter and collect it in the soot storage chamber. A technique has been developed in which incineration is performed by an electric heater in a storage room (see, for example, Japanese Patent Laid-Open No. Sho-Kaiyo).
64-77715, "Particle processing device and filter body for diesel engine exhaust gas").

By the way, the soot adhering to the above-mentioned filter is, of course, peeled off and dropped from the filter at the time of backwashing in which the backwash air is applied to the filter. To fall. Therefore, in the conventional soot removing device for exhaust gas,
The electric heater was always in operation in order to burn the soot.

[Problems to be Solved by the Invention] However, this has a problem that the electric power consumption of the electric heater is large and the load of the vehicle battery and the generator is large. In addition, the electric heater, which is frequently used, may be broken, and in that case, it becomes impossible to process the soot in the soot storage chamber.

Therefore, the inventor of the present invention has previously developed a technique for incinerating the soot in the soot storage chamber by utilizing the heat of exhaust gas (Japanese Patent Application No. 2-225435 "Method and apparatus for burning particulates in exhaust gas". )). This technique forms a soot combustion chamber that burns soot by using heat of exhaust gas in an exhaust pipe line, and sends the soot in the soot storage chamber to the soot combustion chamber by compressed air (sus feed air). It is designed to be incinerated with exhaust gas heat. As a result, the frequency of use of the electric heater can be reduced, and even if the electric heater should fail, soot treatment can be performed.

However, in this technique, backwash air for brushing off the soot adhering to the filter to the soot storage chamber, and soot feed air for pumping the soot in the soot storage chamber to the soot combustion chamber are required, There is a problem that the amount of air consumption becomes large. This air is generated by a compressor and is normally used as a working fluid such as a brake and a clutch of a vehicle. Therefore, such large consumption of air for the treatment of soot undesirably increases the amount of wasteful work of the compressor and reduces the reliability of the operation of the brakes and clutches.

The object of the present invention, which was devised in view of the above circumstances, is to collect soot contained in exhaust gas with a filter, and to incinerate the soot contained in the exhaust gas with the heat of the exhaust gas to remove the soot from the exhaust gas. The present invention provides a soot removing device in exhaust gas that can reduce the consumption of compressed air used for operating a clutch and the like.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a filter for collecting soot contained in exhaust gas, and a soot by jetting backwash air to the filter in a direction opposite to the exhaust gas. In the soot removing device in the exhaust gas, which has a backwashing means for brushing off the soot, and a storage chamber for storing the soot washed off by the backwashing means,
A combustion chamber that burns soot by the heat of exhaust gas, a transfer path that connects the combustion chamber and the storage chamber, and a soot transfer means that pressurizes soot in the storage chamber through the transfer path to the combustion chamber by soot sending air. And a control unit for ejecting the soot feed air for a predetermined time only immediately after the ejection of the backwash air.

[Operation] According to the above configuration, the soot in the exhaust gas collected by the filter is blown off by the backwash air of the backwash means and stored in the storage chamber. The soot in the storage chamber is pressure-fed to the combustion chamber through the transfer path by the soot feed air of the soot transfer means, and burned by the heat of the exhaust gas.

At this time, the control unit ejects the soot feeding air for a predetermined time only immediately after the ejection of the backwash air. In other words, the soot feeding by soot feeding air from the storage chamber to the combustion chamber is
In synchronization with the backwashing of the filter, it is performed for a predetermined time only immediately after the backwashing air is jetted. Therefore, the consumption amount of soot feeding air is reduced.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an outline of a soot removing device 1 for removing soot from the exhaust gas of a diesel engine. As shown in the figure, a filter 4 for adhering and collecting soot contained in the exhaust gas G is provided in the exhaust pipe 3 from the engine 2 to the muffler. The filter 4 is made of, for example, a porous ventilation material such as a ceramics porous material, and has a plurality of cylindrical exhaust gas passages formed in the vertical direction.

In the exhaust pipe line 5 on the downstream side of the filter 4, there is provided a backwash means 7 for ejecting the backwash air 6 to the filter 4 in the direction opposite to the exhaust gas G to remove the soot adhering to the filter 4. . The backwashing means 7 includes an air nozzle 8 provided toward the side portion of the filter 4 and the air nozzle 8
An air tank (not shown) for supplying backwash air to the tank, an opening / closing valve 9 interposed between this tank and the nozzle 8, and an opening / closing valve 10 for closing the exhaust pipe line on the downstream side of the filter during backwashing. ing. These on-off valves 9 and 10 are connected to the CPU 11, and are set at predetermined time intervals (5 in this embodiment).
The backwash operation is performed every (minute interval).

In order to store the soot removed from the filter 4 by the backwash means 7, a soot storage chamber is provided below the filter 4.
Twelve are provided. An electric heater 13 for incinerating soot is provided in the soot storage chamber 12. The electric heater 13 detects the soot level sensor 14 provided under the filter 4 only when the soot level sensor 14 detects that the level of the soot discharged from the filter 4 is equal to or higher than a predetermined level.
It is turned on by 1.

A soot combustion chamber 16 for combusting soot by the heat of the exhaust gas G is provided near the collecting portion 15 of the exhaust manifold on the upstream side of the exhaust pipe line 3. This soot combustion chamber
As shown in FIG. 2, 16 is formed by branching a part of the exhaust pipe line 3, and has an inlet side 16a wide and an outlet side 16b narrow. As a result, a sufficient amount of exhaust gas introduced into the soot combustion chamber 16 can be secured, and the exhaust gas flow in the soot combustion chamber 16 is delayed to achieve sufficient heat input.

As shown in FIG. 1, the soot combustion chamber 16 and the soot storage chamber 12 are communicated with each other by a soot transfer passage 17, through which the soot in the soot storage chamber 12 is compressed (soot feed air). 18) to transfer to the soot combustion chamber 16. The soot transfer means 19 for ejecting the soot feed air 18 is composed of a compressed air supply pipe connected to the soot storage chamber 12 and 20, and an opening / closing valve 21 for opening and closing the supply pipe line 20. The open / close valve 21 is connected to the CPU 11. The CPU 11 is connected to the engine speed sensor 22 and the engine load sensor 23, and estimates and calculates the exhaust gas temperature in the soot combustion chamber 16 based on the information from these sensors 22 and 23, and the temperature is combustion of soot. The above-mentioned on-off valve 21 only when the available temperature is reached
Is designed to open.

Further, as shown in FIG. 3, the soot storage chamber 12 has
A reed valve 24 is provided so as to be separated from the upper filter 4 side. The reed valve 24 is closed by the pressure of the soot feed air 18 so that the soot C in the soot storage chamber 12 does not flow back to the filter 4 side. On the other hand, soot combustion chamber
As shown in FIG. 2, the reed valve 26 is provided in the connection hole 25 between the soot combustion chamber 16 and the soot transfer passage 17 in the valve 16. The reed valve 26 is opened by the soot feed air 18 to prevent the backflow of the soot C in the soot combustion chamber 16.

An on-off valve 9 for controlling the backwash air 6 and soot feed air
The on-off valve 21 for controlling 18 is connected to a control unit 27 provided in the CPU 11, and by this control unit 27, the soot feed air 18 is supplied for a predetermined time (immediately after the backwash air 6 is jetted). It is designed to eject only for 5 seconds. That is,
The control unit 27 controls the opening / closing valve 9 so as to open / close the backwashing air 6 from the air nozzle 8 in a pulsed manner, and then opens / closes the opening / closing valve 21.
Has a function of opening the valve for 5 seconds.

The operation of this embodiment having the above configuration will be described with reference to the flow charts shown in FIGS. 4 and 5.

When the driver starts the start key, the backwash control is performed according to the flowchart shown in FIG. As shown in the figure, the CPU 11 resets the built-in timer to set the initial value of the time to 0 (step 1 in FIG. 5), and also sets the engine speed Ne and the engine load L to the respective sensors 22,
Read from 3 (step 2). Then, it is checked whether or not a predetermined time (5 minutes) has elapsed from the reset time (step 3). The soot C in the exhaust gas is continuously collected by the filter 4 shown in FIG. 1 for these 5 minutes. After 5 minutes, CPU11, Ne <1000rpm, L
Check <1/2 (step 4). At this time, Ne
If L and L do not satisfy the above condition, the check is continued until the condition is satisfied. When the above conditions are satisfied, the CPU 11 causes the open / close valve 9 of the backwash means 7 shown in FIG.
Is opened and the filter 4 is backwashed.

Immediately after such backwashing of the filter 4, the soot combustion control shown in FIG. 4 starts. That is, CPU11
The control unit 27 in the table checks whether or not the backwashing of the filter 4 has been performed, and immediately after the backwashing, the flow proceeds to the following flow. (FIG. 4, step 1). Then, the engine speed Ne, the engine load L and the soot collection amount M are read from the respective sensors 22, 23, 14 (step 2).
Then, it is checked whether the amount M of collected soot exceeds a predetermined amount (step 3). When M exceeds the predetermined amount, the electric heater 13 is turned on to incinerate the soot C in the soot storage chamber 12 (step 4). When M is equal to or less than the predetermined amount, the electric heater 13 is turned off (step 5).

Next, the CPU 11 checks Ne> 1000 rpm and L> 3/4 (step 6). The conditions of Ne and L are conditions for determining whether the exhaust gas temperature in the soot combustion chamber 16 has reached the combustible temperature of the soot C. If Ne and L do not satisfy the above conditions, it is determined that the exhaust gas temperature in the soot combustion chamber 16 is lower than the combustible temperature of the soot C, and the process returns to step 2. When Ne and L satisfy the above conditions, the timer of the on-off valve 21 of the soot transfer means 19 is reset to set the initial value of the time to 0 (step 7), and then the on-off valve 21 is opened (the same step). 8).

Then, the soot C in the soot storage chamber 12 is pressure-fed to the soot combustion chamber 16 by the soot feed air 18. The opening and closing of the on-off valve 21 is continued until a predetermined time (5 seconds) has elapsed from the reset time (step 9). After 5 seconds, the on-off valve 21 is closed and the process returns to step 1.

In this way, the control unit 27 in the CPU 11 controls the backwash air 6
The soot feed air 18 is jetted for a predetermined time (5 seconds) only immediately after the jetting. That is, the pressure feed of the soot C from the soot storage chamber 12 to the soot combustion chamber 16 by the soot feed air 18 is performed for 5 seconds only immediately after the backwash air is jetted, in synchronization with the backwash of the filter 4.

Therefore, the consumption of the soot feed air 18 is reduced. As a result, the amount of wasted work of the compressor that generates the soot feed air 18 can be reduced. Furthermore, since this air is normally used to operate the brakes and clutches, soot C
Reducing the amount of air used for combustion of these will improve the reliability of their operation.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects can be exhibited.

(1) It is possible to reduce the consumption of soot feed air for pressure-feeding the soot in the storage chamber to the combustion chamber.

(2) Therefore, the consumption of compressed air used for the operation of the brake, the clutch, etc. is reduced, and the reliability of those operations is improved.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a soot removing device for exhaust gas showing one embodiment of the present invention, FIG. 2 is a side sectional view showing a combustion chamber in FIG. 1, and FIG. 3 is in FIG. Side sectional view showing the storage chamber of
FIG. 4 is a flowchart of soot combustion control, and FIG. 5 is a flowchart of backwash control. In the figure, 1 is a soot removing device, 4 is a filter, 6 is backwash air, 7 is backwash means, 12 is a storage chamber, 15 is a combustion chamber, 17 is a transfer path, 18 is soot feed air, and 19 is soot transfer. Means, 27 is a control unit, G is exhaust gas, and C is soot.

Claims (1)

(57) [Scope of utility model registration request] 1. A filter for collecting soot contained in exhaust gas, a backwash means for jetting backwash air to the filter in a direction opposite to that of exhaust gas to remove soot, and a backwash means for washing the soot. In a soot removing device for exhaust gas having a storage chamber for storing the dropped soot, a combustion chamber for burning the soot by the heat of the exhaust gas, a transfer path for connecting the combustion chamber and the storage chamber, A soot transfer means for pressurizing the soot in the storage chamber to the combustion chamber by soot feed air through the transfer path, and a controller for ejecting the soot feed air for a predetermined time only immediately after the backwash air ejection are provided. A characteristic soot removal device for exhaust gas.