JPH05179931A - Particulate trap mechanism - Google Patents

Abstract

PURPOSE:To perform burning up and electric power saving respectively surely so as to improve regenerative efficiency when particulates collected in a filter are burnt up and removed by controlling the length of a preheat time and a heater electrifying time according to the height of heater temperature. CONSTITUTION:Particulate trap devices 10, 20 are respectively interposed in the respective branched passages 3a, 3b of an exhaust gas passage 3 connected to the exhaust pipe 2 of an engine 1. Respective filters 12, 22 to collect particulates and respective heaters to ignite them are internally received in their respective casings 11, 21. When particulates collected in the respective filters 12, 22 are burnt up and removed, a blower 50 to introduce open air is started to operate after starting current supply to the respective heaters 13, 23 by control from a controller 60. In this case, if the temperatures of the respective heaters 13, 23 respectively detected by respective temperature sensors 15, 25 are low, the time up to start of operation of the blower and the electrifying time for the respective heaters are lengthened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particulate trap mechanism for removing particulates in the exhaust gas of an engine, and has an improved trap regeneration rate and power saving.

[0002]

2. Description of the Related Art Exhaust gas from an automobile diesel engine contains a large amount of particulates containing carbon fine particles as a main component. Therefore, for environmental protection, a trap device for collecting the particulates is attached to the exhaust gas passage.

There are various types of particulate trap devices. For example, it is known that a casing is provided in the middle of an exhaust gas passage, and a ceramic filter having a honeycomb structure is fixed and filled in the casing. In this device, particulates in the exhaust gas flowing from the upstream are collected by this filter and deposited on the filter.

If the amount of particulates deposited on the filter becomes too large, the exhaust pressure rises and fuel consumption deteriorates. Therefore, the particulates must be burned and removed at an appropriate time to regenerate the filter. To remove the particulates by burning, an electric heater arranged normally upstream of the filter is operated, and the heat ignites the particulates.
Using it as an ignition source, a method of sequentially burning the particulates accumulated on the filter from the upstream side to the downstream side is used. When burning the particulates in this way, the blower is operated to supply the outside air into the particulate trap device to accelerate the burning.

In this way, the filter from which the particulates are removed and regenerated collects the particulates again.

The energization timing of the electric heater and the operation timing of the blower are as shown in FIG. That is, the preheating period I in which the heater is energized and the blower is not operated, and the period in which the heater is energized and the blower is operated
II and the period for operating the blower without energizing the heater II
I have The reason why the period I is provided for preheating is that the higher the initial temperature when the filter is burned and removed, the higher the regeneration rate of the trap.

[0007]

Conventionally, in the operation shown in FIG. 3, the ON / OFF timing of the heater and the ON / OFF timing of the blower are fixed, and the preheat period I is always a constant time. However, even before combustion removal, the temperature of the filter of the particulate trap device differs depending on the state of exhaust gas and the like. For this reason, since the preheating period is constant, when the filter temperature before combustion removal is low, preheating becomes insufficient and the regeneration rate deteriorates. On the contrary, when the filter temperature before combustion removal is high, preheating becomes excessive and power is wasted.

In view of the above-mentioned prior art, the present invention provides an effective particulate trap mechanism capable of removing particulates without waste.

[0009]

The structure of the present invention for solving the above-mentioned problems is provided in the middle of the exhaust gas passage,
A particulate trap device incorporating a filter for collecting particulates and a heater for igniting the accumulated particulates, a blower means for introducing outside air into the particulate trap device, and a heater temperature detecting means for detecting the temperature of the heater. And a controller for controlling the operation of the blower to be started after the energization of the heater is started when the particulates are burned and removed, and the heater temperature detected by the heater temperature detecting means is input. However, the controller, when the heater temperature immediately before burning and removing the particulates is low, lengthens the time from starting the energization of the heater to starting the operation of the blower and lengthens the energization time to the heater, When the heater temperature is high just before burning off particulates And controlling so as to shorten the energizing time to the heater as well as shorten the time from the start of the energization of the heater to the start of operation of the blower.

[0010]

When the initial temperature of the filter of the particulate device is low, the preheat time and the heater energization time are lengthened to ensure reliable combustion removal, and when the filter initial temperature is high, the preheat time and the heater energization time are shortened to save power. Try to.

[0011]

FIG. 1 shows an embodiment of the present invention. As shown in the figure, an exhaust gas passage 3 is connected to an exhaust pipe 2 of an engine 1, and the exhaust gas passage 3 is connected to the exhaust gas passages 3a, 3a from the middle.
It is bifurcated into b. Particulate trap devices 10 and 20 are provided in the exhaust gas passages 3a and 3b, respectively. Inside the casings 11 and 21 of the particulate trap devices 10 and 20, filters 12 and 22 for collecting particulates in the exhaust gas, heaters 13 and 23 for igniting the particulates, and heat reflection plates 14 and 24 are incorporated. Has been done. Further, the filters 12 and 22 are provided with temperature sensors 15 and 25.

On-off valves 30, 40 are provided upstream of the particulate trap devices 10, 20 in the exhaust gas passages 3a, 3b. The on-off valves 30, 40 are opened and closed by opening and closing the valves 31, 41. Controlled. On the other hand, the blower 50 takes in outside air through the air filter 51,
Outside air is supplied to the particulate trap devices 10 and 20 when the valves 52 and 53 are open.

The battery B is the power source of this embodiment, and when the relays R1 and R2 are turned on, the heaters 13 and 23 are turned on.
Is energized to generate heat, and when the relay R3 is turned on, the blower 50 operates. The controller 60 is powered by the battery B. This controller 60 is a relay R
1, R2 ON / OFF (that is, energization / de-energization of the heaters 13 and 23) and relay R3 ON / OFF (blower 50)
Operation, non-operation) and opening / closing of valves 31 and 41 (open / close valve 3
0/40) and valves 52, 53 (open air introduction) are controlled. The temperatures of the filters 12 and 22 detected by the temperature sensors 15 and 25 are sent to the controller 60.

When burning and removing the particulates accumulated on the filter 12 of the particulate trap device 10, the heater 13 is energized, the opening / closing valve 30 is closed, and the valve 52 is opened to open the outside air from the blower 50 to the filter 12 side. Introduce. At this time, the opening / closing valve 40 is left open, and all the exhaust gas is allowed to flow into the particulate trap device 20. The valve 53 is closed. On the contrary, in order to burn and remove the particulates accumulated on the filter 22 of the particulate trap device 20, the heater 23 is energized, the opening / closing valve 40 is closed, and the valve 53 is opened to open the blower 5
Outside air is introduced from 0 to the filter 22 side. At this time, the opening / closing valve 30 is left open, and all the exhaust gas is allowed to flow into the particulate trap device 10. The valve 52 is closed.

Next, a procedure by the controller 60 for burning and removing particulates will be described. Since the operation procedure of the particulate trap device 10 and the particulate trap device 20 is the same, the device 10 side will be described as a representative.

When the particulates are deposited on the filter 12 of the particulate trap device 10 to a certain extent or more, the controller 60 outputs a signal to the relay R1 to turn on the relay R1 to cause the heater 13 to be energized. Preheating is performed by this energization. This operation corresponds to time I in FIG. After preheating for a certain period of time, the controller 60 sends a signal to the valve 31 to close the opening / closing valve 30. At the same time, the valve 52 is opened and the blower 50 is operated with the valve 53 kept closed. Thus, heating by the heater 14 and introduction of outside air by the blower 50 are performed. This operation corresponds to the period II in FIG. After that, when a certain amount of time has passed, the heater 13 is de-energized and only the outside air is introduced. This operation corresponds to the period III in FIG. Then, the blower 50 is stopped.

In the present embodiment, the operation start timing of the blower 50 and the energization time to the heater 14 during the above operation are changed according to the temperature of the filter 12 immediately before combustion removal. This will be described with reference to FIG.

As shown in FIG. 2A, when the temperature of the filter 12 is 0 to 200 ° C. immediately before the start of combustion removal, the preheat time from the start of energization of the heater 13 to the start of operation of the blower 50. T _{P is set} to 9 [minutes], and the preheating time is lengthened. Also are the energization time T _H of the heater 14 as long as 15 [min]. Thus, since the initial temperature of the heater 13 is sufficiently high, the particulates can be effectively removed.

As shown in FIG. 2B, when the temperature of the filter 12 immediately before the start of combustion removal is 200 to 400 ° C., the preheat time T _{P is set} to 6 [minutes] and the heater 14 is used.
The energization time T _{H is set} to 12 minutes. Since the initial filter temperature is high to some extent, the preheat period is somewhat shortened.

As shown in FIG. 2 (c), when the temperature of the filter 12 is 400 ° C. or more immediately before the start of combustion removal, the preheat time T _{P is set} to 3 [minutes] and the heater 14 energization time T _{H is set} to 9 minutes. I have a minute. Thus, when the initial filter temperature is extremely high, the preheat time and the heater energization time are shortened to save power. Even in this case, since the initial temperature of the filter 14 is high,
The particulates can be reliably removed.

[0021]

As described above, according to the present invention, the preheat time and the heater energization time are lengthened when the temperature of the filter is low immediately before the start of combustion removal,
It is possible to reliably remove the particulates. Further, when the temperature of the filter is high immediately before the start of combustion removal, the preheat time and the heater energization time can be shortened to save power. Thus, the trap regeneration rate is improved and power saving is achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a time chart showing the operation status of the embodiment.

FIG. 3 is a time chart showing operating states of a heater and a blower.

[Explanation of symbols]

 1 engine 2 exhaust pipe 3,3a, 3b exhaust gas passage 10,20 particulate trap device 11,21 casing 12,22 filter 13,23 heater 14,24 heat reflecting plate 15,25 temperature sensor 30,40 on-off valve 31,41 Valve 50 Blower 51 Air filter 52,53 Valve 60 Controller R1, R2, R3 Relay B Battery

Claims (1)

[Claims] 1. A particulate trap device, which is provided in the middle of an exhaust gas passage and has a filter for collecting particulates and a heater for igniting accumulated particulates, and external air introduced into the particulate trap device. And a heater temperature detecting means for detecting the temperature of the heater, and a control for starting the operation of the blower after the energization of the heater is started when the particulates are burned and removed. A controller to which the heater temperature detected by the temperature detecting means is input, wherein the controller starts energizing the heater and then starts the operation of the blower when the heater temperature immediately before burning and removing particulates is low. Until the heater is energized and the heater When the heater temperature is high immediately before burning and removing the curate, the time from the start of energizing the heater to the start of the blower operation is shortened and the energizing time to the heater is shortened. Particulate trap mechanism.