JPH0634575Y2 - Particulate trap filter regenerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a particulate trap filter regeneration device.

<Prior Art> In a diesel engine or the like, a trap filter for trapping exhaust particulate matter (hereinafter referred to as “particulate”) contained in exhaust gas is provided in the exhaust passage, but the particulate matter contained in the exhaust gas is When trapped in the trap filter and the amount of collected particulates increases, clogging of the trap filter increases exhaust pressure and reduces engine performance.

For this reason, conventionally, there is a device in which a heating device such as a heater is arranged on the outer peripheral portion of the trap filter to burn and remove the particulates trapped in the trap filter to regenerate the trap filter. (For example,
See Japanese Utility Model Publication No. 63-46652).

By the way, the particulates have a certain temperature (about 500 ℃)
If it is not above, it will not burn and if the temperature rises too much (10
(Over 00 ℃) The trap filter will be melted. Therefore, conventionally, the heating unit of the regenerator is arranged in the center of the trap filter to heat the trap filter, the temperature of the heated trap filter is detected by the temperature detection means, and the temperature controller traps the temperature according to the detected temperature. In addition to controlling the temperature of the filter, by controlling the fan at the air inlet and the passage opening / closing valve at the exhaust passage, the amount of air sent into the trap filter is adjusted during trap filter regeneration to control its temperature. There are some (Shinkaisho 63-132
(See gazette 822).

<Problems to be Solved by the Invention> However, in the configuration in which the heater is heated from the outer peripheral portion of the trap filter as in the former case, the temperature rise in the central portion of the trap filter is not sufficient and the temperature distribution in the trap filter is There is a problem that the particles are not made uniform and the particulates cannot be completely removed by burning.

On the contrary, in the latter case, in which the heater is heated from the central part of the trap filter, the temperature of the outer peripheral part of the trap filter does not rise sufficiently, and there is a problem that the particulates cannot be completely removed by combustion. is there.

The applicant of the present invention collects the particulates generated by the vehicle while the vehicle is traveling, connects the temperature control means to a power source outside the vehicle after the traveling, and operates the trap filter according to the temperature detected by the temperature detecting means. A trap filter regenerator configured to control the heating of an electric heater so that the temperature becomes a constant temperature, and to close a passage opening / closing valve provided in an exhaust passage in order to burn particulates with a limited amount of air. Proposed (see Jpn. Pat. Appln. 1-27247).

By the way, in the case of such a proposal, since gentle particulate combustion is performed as in the electric furnace,
Although it is possible to safely and reliably remove particulates and regenerate it, the temperature rise at the center is slower than the temperature rise at the outer periphery while the temperature of the trap filter is raised to the regeneration temperature after the electric heater is energized. There is a problem that the temperature rise cannot be accelerated so that the trap filter is not cracked due to a large temperature difference between the outer peripheral portion and the outer peripheral portion, so that the regeneration takes time.

The present invention has been made in view of the above situation, and does not cause the particulate trap filter to melt and
In addition, the objective was to completely burn the particulates in the shortest possible time to regenerate the trap filter.

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. 1, a particulate trap / trap filter regenerator having a trap filter interposed in an exhaust passage of an engine to collect particulates. An electric heater for heating the filter is provided on the outer peripheral portion of the trap filter, and an outer peripheral temperature detecting means for detecting the temperature of the outer peripheral portion of the trap filter and a central portion temperature detection for detecting the temperature of the central portion of the trap filter. Means and control means for controlling energization to the electric heater according to the temperature of the outer peripheral portion of the trap filter detected by each of the temperature detecting means, the temperature of the central portion and the detected temperature difference between the outer peripheral portion and the central portion. , Is provided.

<Operation> According to this configuration, the control means causes the trap filter to operate in accordance with the detected temperature of the outer peripheral portion of the trap filter and the temperature of the central portion of the trap filter, and further the detected temperature difference between the outer peripheral portion and the central portion. The electric heater disposed on the outer peripheral portion of the trap filter is energized and controlled so that the temperature difference of 1 is suppressed to a specified value or less and the temperature is raised to the regeneration temperature.

Therefore, heating is performed to regenerate the trap filter as quickly and effectively as possible, and it is possible to prevent partial melting loss of the trap filter and crack generation of the trap filter, and to uniformly regenerate the entire trap filter. You can do it.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, an electric heater 3 (hereinafter, simply referred to as a heater 3) is provided on the outer periphery of a trap filter (hereinafter, simply referred to as a filter) 1 via a cushion material 2 so as to be wound around the outer periphery thereof. The heater 3 is fixed by a heater fixing heat insulating material 4. Further, the particulate trap filter 7 is configured by providing the heat insulating material 5 also serving as a cushioning material around the heat insulating material 4 and holding it by the filter case 6. In the particulate trap filter 7, a thermocouple 8a for detecting the temperature Th of the heater 3 wound around the outer periphery of the filter 1 is inserted into the heater fixing heat insulating material 4 from the side, and the central portion of the filter 1 is also inserted. A thermocouple 8c as a central temperature detecting means for detecting the temperature Tc of the filter 1 is inserted into the inside of the filter 1 from the downstream end face of the filter 1. Since the filter 1 is held by the filter case 6 via the heat insulating materials 4 and 5, the temperature Th of the heater 3 detected by the thermocouple 8a is substantially equal to the temperature Ta of the outer peripheral portion of the filter 1, and thus the thermoelectric temperature is equal. The pair 8a serves as an outer peripheral temperature detecting means for detecting the temperature Ta of the outer peripheral portion of the filter 1.

The particulate trap filter 7 is fixed to the exhaust passage 10 by fastening both ends of the filter case 6 with bolts 9.

Solenoid valves 11a and 11 are provided on the upstream and downstream sides of the exhaust passage 10, respectively.
Passage on-off valves 13a, 13b that are opened and closed by air cylinders 12a, 12b driven by b are provided. Also, the exhaust passage 1
A heat insulating material 14 is attached to the inner surfaces of the passage opening / closing valves 13a and 13b so as to keep the temperature of the filter 1.

The detection signals from the thermocouples 8a and 8c are input to the temperature control unit 15 as a control means for controlling the energization of the heater 3, while the control signals are output to the solenoid valves 11a and 11b and the heater 3. In addition, 16 is an external power supply connection outlet.

Next, the operation will be described.

Filter the generated particulates while the vehicle is running 1
To collect. Then, for example, when one day's traveling is completed and the vehicle is put in a garage or the like, the external power source connection outlet 16 is connected to an external power source such as a commercial power source and the temperature control unit 15 energizes the solenoid valves 11a, 11b on the upstream and downstream sides. Air cylinder 1
The passage opening / closing valves 13a, 13b are closed via 2 to restrict the inflow of air into the filter 1, and the temperature control unit 15 controls the operation of the heater 3 and its stop based on the flowchart shown in FIG. , Filter 1 is regenerated.

The operation of the temperature control unit 15 will be described below with reference to the flowchart of FIG.

In step (denoted as S in the figure. The same applies to the following) 1, the thermocouple 8a
And 8c, the temperature Th of the heater 3 and the temperature Tc of the central portion of the filter 1 are detected. As mentioned above, the temperature Th is approximately the temperature.
Since it is equal to Ta, the temperature Th is the temperature Ta of the outer peripheral portion of the filter 1.
Read as

In step 2, it is judged whether or not the temperature Ta is lower than _a preset allowable maximum temperature T _{a max of the} filter outer peripheral portion, and if the temperature Ta is lower than the allowable maximum temperature T _{a max} , the outer peripheral portion of the filter 1 is not yet heated. However, assuming that there is no fear of melting damage, proceed to step 3.

In step 3, it is judged whether the maximum allowable temperature Tc _{max of the} filter central part, which is set in advance, has not been proposed, and if it is less than the maximum allowable temperature _{Tc max} , the central part of the filter 1 is still heated. However, if there is no fear of melting, proceed to step 4. Note that T _{c max} and T _{a max} are T _{c max} <T _{a max.
It} may be _{c max} = T _{a max} .

In step 4, a temperature difference ΔT (= Ta−Tc) between the temperature Ta of the outer peripheral portion of the filter 1 and the temperature Tc of the central portion is calculated.

Here, if the temperature difference ΔT is large, cracks may occur in the filter 1 due to the temperature gradient, but the maximum allowable temperature difference that does not cause cracks is T1. Then, in step 5, it is judged whether or not the temperature difference ΔT is larger than the maximum allowable temperature difference T1 at which a crack does not occur. When the temperature difference ΔT is large, the filter 1
Since there is a risk of cracks occurring in the filter, regardless of the temperature Ta of the outer peripheral portion of the filter and the temperature Tc of the central portion of the filter, the process proceeds to step 6, the heater 3 is turned off and the initial routine is returned to.

Even if NO is determined in step 2 or step 3, the process proceeds to step 6.

On the other hand, if the temperature difference ΔT is not larger than the maximum allowable temperature difference T1 in step 5, the heater 3 may be turned on.
The other judgment is made to determine whether to turn on the heater 3. That is, in this embodiment, the maximum allowable temperature difference T1 is set as large as possible in order to regenerate the filter 1 as quickly as possible. Therefore, at this T1, heater 3
If the ON point is determined, ΔT becomes large due to a rapid increase in the temperature Ta of the outer peripheral portion of the filter 1 after the heater 3 is turned ON, and the allowable maximum temperature difference T1 is greatly exceeded, and the heater 3 OFF control is not in time and cracks occur. There is a fear that it will occur.

Therefore, a hysteresis is provided between the OFF point and the ON point of the heater 3 so that the temperature of the ON point of the heater 3 is lower than that of the OFF point of the heater 3.

That is, the heater energization temperature difference T2 (= T1) which is smaller than the allowable maximum temperature difference T1 by the temperature α corresponding to the hysteresis.
-Α) is set, and in step 7, it is determined whether the temperature difference ΔT is less than the heater energization temperature difference T2 described above. If ΔT is less than T2, the process proceeds to step 8 to turn on the heater 3 to regenerate the filter 1.

On the other hand, if ΔT is not less than T2 in step 7, the process jumps to step 1 and the above-mentioned determination is executed again.

In this way, the temperature Tc of the central portion of the filter 1, the temperature Ta of the outer peripheral portion, and the temperature difference ΔT between the outer peripheral portion and the central portion are obtained and the heating of the heater 3 of the filter 1 is controlled. The heater 3 can be energized according to the amount of the collected curate, and the heating for regenerating the filter 1 can be effectively performed. Moreover, since the hysteresis is provided between the OFF point and the ON point of the heater 3 to control the energization of the heater 3, even if the allowable maximum temperature difference T1 is set to be large, the filter 1 may be cracked. Instead, as shown in FIG. 4, the temperature of the filter 1 rises and the regeneration can be performed as quickly as possible.

Further, when the regeneration of the filter 1 is completed, the power supply to the heater 3 is turned off, so that wasteful power consumption can be prevented.

<Effect of Device> As described above, the particulate trap / filter regenerating device of the present invention controls energization to the heater according to the temperature of the outer peripheral portion and the temperature of the central portion of the trap filter. While preventing partial melting and damage of the trap filter and cracking of the trap filter,
It becomes possible to regenerate the entire trap filter effectively and quickly in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a particulate trap filter regeneration device according to the present invention, FIG. 2 is a system configuration diagram showing an embodiment according to the present invention, and FIG. 3 is a control content of the same embodiment. FIG. 4 is a time chart showing the temperature rise of the filter for explaining the operation of the above embodiment. 1 ... Trap filter, 3 ... Heater, 8a, 8c ... Thermocouple, 15 ... Temperature control unit

Claims (1)

[Scope of utility model registration request] 1. A particulate trap / trap filter regenerator having a trap filter for trapping particulate matter, which is interposed in an exhaust passage of an engine, wherein an electric heater for heating the filter is arranged on an outer peripheral portion of the trap filter. An outer peripheral temperature detecting means for detecting the temperature of the outer peripheral portion of the trap filter, a central portion temperature detecting means for detecting the temperature of the central portion of the trap filter, and an outer peripheral portion of the trap filter detected by the temperature detecting means. Temperature, the temperature of the central portion, and a control means for controlling energization to the electric heater according to the detected temperature difference between the outer peripheral portion and the central portion,
A particulate trap filter regenerator characterized by comprising: