JPH05179932A - 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 a heater by controlling the length of a preheat time according to the height of battery voltage against heaters. 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. l In this case, if the voltage value of a battery B is low, the time from the beginning of electrifying the heaters up to start of operation of the blower is lengthened by means of a controller 60.

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 is designed to improve the trap regeneration rate.

[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. 4, the heater ON / OFF timing and the blower ON / OFF timing are fixed, and the preheat period I is always a constant time. However, since the voltage value of the battery fluctuates, even if the preheating time is constant, the temperature rise characteristics of the filter may be different, and the trap regeneration rate may vary. Even before combustion removal, the temperature of the filter of the particulate trap device differs depending on the state of exhaust gas. Therefore, even if 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, the preheat becomes excessive.

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 having a filter for collecting the particulates and a heater for igniting the accumulated particulates, a blower means for introducing outside air into the particulate trap device, and a voltage detecting means for detecting the temperature of the battery. 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 battery voltage value detected by the voltage detection means is input. When the battery voltage value immediately before burning and removing particulates is low, the controller lengthens the time from the start of energizing the heater to the start of operation of the blower, and the battery immediately before burning and removing particulates is removed. When the voltage value is high, start the energization of the heater and then start the blower. And controlling so as to shorten the time until the start of operation.

[0010]

The preheat time is lengthened when the initial temperature of the filter of the particulate device is low or the battery voltage is low, and the preheat time is shortened when the initial temperature of the filter is high or the battery voltage is high.

[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. Further, the voltage of the battery B can be detected through the lines L1 and L2 and the relays R1 and R2 that are turned on.

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 during the above operation is changed according to the voltage of the battery B immediately before combustion removal. This will be described with reference to FIG.

As shown in FIG. 2 (a), when the voltage of the battery B is less than 11.6V 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. Since the preheating time is lengthened when the voltage is low as described above, the temperature of the filter 12 after preheating has an appropriate value, and particulates can be effectively removed.

As shown in FIG. 2 (b), when the voltage of the battery B immediately before the start of combustion removal is within the reference range of 11.6V or more and less than 12.2V, the preheat time T _P is 6 [minutes] according to the reference. I am trying. Therefore, the temperature of the filter 12 after preheating becomes an appropriate value, and the particulates can be effectively removed.

As shown in FIG. 2 (c), when the voltage of the battery B is 12.2 V or more immediately before the start of combustion removal, the preheat time T _P is shortened to 3 minutes. Thus, when the voltage of the battery B is high, even if the preheating time is shortened, the temperature of the filter 12 after preheating becomes an appropriate value, and the particulates can be effectively removed.

As described above, in the present invention, the preheating time is controlled according to the voltage fluctuation of the battery B, and the filter temperature after preheating is set to an appropriate value. Therefore, even if the battery voltage fluctuates, optimum particulates can always be removed.

As shown in FIG. 1, two particulate trap devices 10 and 20 are provided, and when the trap regeneration of one device 10 is followed by the trap regeneration of the other device 20, the battery B is used. Power is consumed and its voltage changes. Therefore, in the mechanism shown in FIG. 1, the utility value of the present invention is particularly high.

FIG. 3 shows the control operation of the second embodiment. In the second embodiment, the preheat time is determined by considering not only the battery voltage but also the filter temperature. That is, the higher the battery voltage and the higher the filter temperature, the shorter the preheat time, and the lower the battery voltage and the lower the filter temperature, the longer the preheat time. When the filter temperature is high, the filter temperature after preheating is appropriate even if the preheating time is short. Therefore, such nine combination modes 1-1 to 3-3
It was set.

[0024]

As described above, according to the present invention, the preheat time is lengthened when the battery voltage or the filter temperature immediately before starting the combustion removal is low, and the battery voltage or the filter immediately before the combustion removal is started. When the temperature is high, the preheating time can be shortened to make the trap regeneration rate uniform.

[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 first embodiment.

FIG. 3 is a diagram showing an operation mode of the second embodiment.

FIG. 4 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 L1, L2 Line

Claims (2)

[Claims] 1. A particulate trap device, which is installed in the middle of an exhaust gas passage and has a built-in filter for collecting particulates and a heater for igniting accumulated particulates; and external air introduced into the particulate trap device. Blower means, a voltage detecting means for detecting the voltage of the battery, 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, and the voltage detecting means. And a controller to which the battery voltage value detected in is input, wherein the controller starts the energization of the heater to start the operation of the blower when the battery voltage value immediately before burning and removing the particulates is low. The battery power immediately before burning and removing particulates. Particulate trap mechanism and controlling so as to shorten the time from the start of the energization of the heater to the start of operation of the blower when a high value. 2. A particulate trap device, which is installed in the middle of the exhaust gas passage and has a built-in filter for collecting particulates and a heater for igniting the deposited particulates, and external air introduced into the particulate trap device. Blower means, a heater temperature detecting means for detecting the temperature of the heater, a voltage detecting means for detecting the voltage of the battery, and a burner of the blower after the energization of the heater is started when burning and removing particulates. While controlling to start the operation, it has a controller to which the heater temperature detected by the heater temperature detecting means and the battery voltage value detected by the voltage detecting means are input, and the controller is provided just before burning and removing particulates. The lower the heater temperature or the lower the battery voltage The time from the start of energizing the heater to the start of the blower operation is lengthened, and the higher the heater temperature immediately before burning off particulates or the higher the battery voltage value, the more energizing the heater starts. A particulate trap mechanism that controls to shorten the time from when the blower starts to operate.