JP2816375B2 - Particulate trap mechanism - Google Patents

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 exhaust gas from an engine, and to improve a trap regeneration rate.

[0002]

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

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 apparatus, the particulates in the exhaust gas flowing from the upstream are collected by this filter and deposited on the filter.

[0004] If the amount of particulates deposited on the filter becomes excessive, the exhaust pressure rises and fuel efficiency deteriorates. Therefore, it is necessary to regenerate the filter by burning and removing the particulates at an appropriate time. The burning and removal of the particulates is usually performed by activating an electric heater disposed upstream of the filter and igniting the particulates with the heat.
Using this as an ignition source, a method of sequentially burning particulates deposited on the filter from the upstream side to the downstream side is used. When burning particulates in this way, a blower is operated to supply outside air into the particulate trap device to promote combustion.

[0005] The filter from which the particulates have been removed and thus 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, a preheating period I in which the heater is energized and the blower is not operated, and a period in which the heater is energized and the blower is operated.
II and the period during which the blower is operated without energizing the heater II
I have The reason why the preheating is performed in the period I is that the higher the initial temperature at the time of burning and removing the filter, the higher the regeneration rate of the trap.

[0007]

Conventionally, in the operation shown in FIG. 4, the ON / OFF timing of the heater and the ON / OFF timing of the blower are fixed, and the preheating period I is always a fixed 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 the combustion removal, the temperature of the filter of the particulate trap device differs depending on the state of the exhaust gas and the like. For this reason, even when the preheating period is constant, when the filter temperature before the combustion removal is low, the preheating is insufficient and the regeneration rate deteriorates. Conversely, when the filter temperature before combustion removal is high, preheating becomes excessive.

The present invention has been made in view of the above-mentioned prior art, and provides a particulate trap mechanism capable of effectively removing particulates without waste.

[0009]

According to the structure of the present invention which solves the above-mentioned problems, the structure is interposed in the exhaust gas passage,
A particulate trap device including a filter for collecting particulates and a heater for igniting the deposited particulates, blower means for introducing outside air to the particulate trap device, and voltage detection 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 burning and removing the particulates, and a battery voltage value detected by the voltage detecting means being input. When the battery voltage value immediately before burning and removing the particulates is low, the controller increases the time from the start of energization to the heater to the start of the operation of the blower, so that the battery just before burning and removing the particulates. If the voltage value is high, start energizing the heater and then And controlling so as to shorten the time until the start of operation.

[0010]

When the battery voltage is low, the preheating time is lengthened, and when the battery voltage is high, the preheating time is shortened.

[0011]

FIG. 1 shows an embodiment of the present invention. As shown in FIG. 1, an exhaust gas passage 3 is connected to an exhaust pipe 2 of the engine 1.
b. In each of the exhaust gas passages 3a, 3b, particulate trap devices 10, 20 are interposed. Filters 12 and 22 for collecting particulates in exhaust gas, heaters 13 and 23 for igniting the particulates, and heat reflecting plates 14 and 24 are built in casings 11 and 21 of the particulate trap devices 10 and 20. Have been. The filters 12 and 22 are provided with temperature sensors 15 and 25, respectively.

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

The battery B is a power source of this embodiment, and the heaters 13 and 23 are turned on when the relays R1 and R2 are turned on.
Is energized and generates 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 has a relay R
1 and R2 (that is, energization and non-energization of the heaters 13 and 23) and ON and OFF of the relay R3 (the blower 50).
Operation, non-operation) and opening / closing of valves 31 and 41 (opening / closing valve 3)
0, 40) and valves 52, 53 (introduction of outside air). Further, the voltage of the battery B can be detected via the lines L1 and L2 and the turned on relays R1 and R2.

When the particulates deposited on the filter 12 of the particulate trap device 10 are burned and removed, the heater 13 is energized, the on-off valve 30 is closed, the valve 52 is opened, and the outside air is blown from the blower 50 to the filter 12 side. Introduce. At this time, the on-off valve 40 is kept open, and all the exhaust gas flows into the particulate trap device 20. The valve 53 is closed. Conversely, to burn and remove the particulates accumulated on the filter 22 of the particulate trap device 20, the heater 23 is energized, the on-off valve 40 is closed, the valve 53 is opened, and the blower 5 is opened.
External air is introduced from 0 to the filter 22 side. At this time, the on-off valve 30 is kept open, and all exhaust gas flows into the particulate trap device 10. The valve 52 is closed.

Next, a procedure by the controller 60 when burning and removing the particulates will be described. The operation procedures of the particulate trap device 10 and the particulate trap device 20 are the same, and therefore the description will be made on the device 10 side as a representative.

When the particulates accumulate on the filter 12 of the particulate trap device 10 to a certain extent or more, the controller 60 sends a signal to the relay R1 to turn on the relay R1 and energize the heater 13. Preheating is performed by this energization. This operation corresponds to time I in FIG. After performing the preheating for a certain time, the controller 60 sends a signal to the valve 31 to close the on-off valve 30. At the same time, the valve 52 is opened and the blower 50 is operated while the valve 53 is kept closed. Thus, heating by the heater 14 and introduction of outside air by the blower 50 are performed. This operation corresponds to period II in FIG. Thereafter, after a certain period of time, the power supply to the heater 13 is stopped, and only the outside air is introduced. This operation corresponds to period III in FIG. Thereafter, the blower 50 is stopped.

In this embodiment, the operation start timing of the blower 50 at the time of performing the above operation is changed according to the voltage of the battery B immediately before the removal of combustion. This will be described with reference to FIG.

As shown in FIG. 2A, when the voltage of the battery B immediately before the start of combustion removal is less than 11.6 V, the preheating time from the start of energization of the heater 13 to the start of operation of the blower 50 is started. 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 the preheating becomes 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 burnoff is within 12.2V less than a reference range of 11.6V, the reference exactly 6 (minutes) preheat time T _P And For this reason, the temperature of the filter 12 after preheating becomes an appropriate value, and particulates can be effectively removed.

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

As described above, in the present invention, the preheating time is controlled in accordance with the voltage fluctuation of the battery B, and the filter temperature after the preheating is set to an appropriate value. Therefore, even if the battery voltage fluctuates, it is possible to always remove the optimal particulate matter.

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

FIG. 3 shows the control operation of the second embodiment. In the second embodiment, the preheating time is determined in consideration of 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, even if the preheating time is short, the filter temperature after preheating is appropriately varied.
It was set.

[0024]

As described above, according to the present invention, when the battery voltage is low immediately before the start of the combustion removal, the preheating time is lengthened, and the battery immediately before the start of the combustion removal is extended. When the voltage is high , the preheating time can be shortened to make the trap regeneration rate uniform.

[Brief description of the drawings]

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

FIG. 2 is a time chart showing an operation state of the first embodiment.

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

FIG. 4 is a time chart showing operation states of a heater and a blower.

[Explanation of symbols]

 DESCRIPTION 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 reflection plate 15,25 Temperature sensor 30,40 Open / close valve 31,41 Valve 50 Blower 51 Air filter 52, 53 Valve 60 Controller R1, R2, R3 Relay B Battery L1, L2 Line

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-64610 (JP, A) JP-A-4-284115 (JP, A) JP-A-3-118216 (JP, U) JP-A-63- 19022 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 3/02 341 F01N 9/00

Claims (1)

(57) [Claims] 1. A particulate trap device interposed in an exhaust gas passage and having a filter for collecting particulates and a heater for igniting the deposited particulates, and introducing outside air into the particulate trap device. A blower means for detecting the voltage of a battery; a control means for starting operation of the blower after energizing the heater when burning and removing the particulates; And a controller to which the battery voltage value detected in step (b) is input. The controller, when the battery voltage value immediately before burning and removing the particulates is low, starts energizing the heater and starts the operation of the blower. Battery time just before burning out 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.