JPH0710031Y2 - Particulate filter - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is provided in an exhaust system of a diesel engine to collect solid fine particles, that is, particulates in exhaust gas, and to collect the collected particulates at regular intervals. The present invention relates to a particulate filter that combusts and is regenerated.

[Conventional technology]

Diesel engines contain particulate matter that is a source of black smoke in the exhaust gas due to incomplete combustion. Therefore, in a diesel engine, in order to remove particulates in exhaust gas, there have been proposed a number of exhaust gas purification devices in which a particulate filter made of a porous material such as ceramic is arranged in the exhaust system of the engine.

By the way, this particulate filter causes clogging with time due to the collection of particulates, and therefore, it is necessary to perform a proper regeneration process. Here, the regeneration of the filter is to burn the accumulated particulates.

For this particulate combustion, an electric heater must be provided on one end surface of the filter, and this heater must be energized to ignite the particulates during regeneration. The filter regeneration section is divided into a plurality of fan sections in cross section due to the restriction of 1), the heater is electrically divided corresponding to the divided regeneration section, and the heater assigned to one regeneration section is changed to the heater of the adjacent regeneration section. There is already known a particulate filter that sequentially energizes to incinerate the particulates (see Japanese Utility Model Laid-Open No. 60-14216).

[Problems to be solved by the device]

In the above-mentioned particulate filter having a fan-shaped regeneration section, for example, when the particulates trapped in the P region are burned as shown in FIG. 4, the generated heat quantity is Q as shown by the arrow in the figure. , R, S, and distributed outside P. Therefore, when the particulate matter trapped in the region of Q is to be burned next, the heat dispersed to the outside of the regions R, S and P is effective for the particulate ignition of the region Q. Not being used, the amount of electric power is increased, and the filter regeneration cost increases.

The present invention has been made in view of such problems, and an object of the present invention is to provide a particulate filter capable of regenerating the filter with a small amount of electric power.

[Means for Solving the Problems]

According to the present invention for the above purpose, a cylindrical particulate filter that collects solid particulates in exhaust gas discharged from a diesel engine is divided into substantially concentric circles near one end surface of the particulate filter body. Corresponding to the filter regeneration section, a plurality of electrically divided electric heater wires are installed, and when the filter is regenerated, it is placed in the regeneration section outside the electric heater wire placed in the regeneration section in the center of the filter. Control means for sequentially energizing the electric heater wire arranged in the regeneration section inside the filter or the electric heater wire arranged in the regeneration section on the outer periphery of the filter. A particulate filter is provided.

[Action]

For example, when the electric heater wire of the regeneration section in the center of the filter is energized to burn the particulates accumulated in this section, a part of the combustion heat is transferred only to the adjacent regeneration section located outside thereof. Therefore, when the particulate matter accumulated in the adjacent regeneration section is burned next time, a part of the heat transferred earlier is effectively contributed to the heating of the electric heater wire necessary for particulate ignition. It requires less electricity. Even when electricity is sequentially supplied to the electric heater wire arranged in the regeneration section inside the filter from the electric heater wire arranged in the regeneration section on the outer periphery of the filter, a part of the particulate combustion heat in the outer periphery regeneration section is adjacent to the electric heater wire. Since it is transmitted to the particulates in the inner regeneration section, the amount of electric power required to ignite the particulates in the adjacent portion is reduced as compared with the related art.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the particulate filter 1 viewed from the end face side.
The wiring of each electric heater is shown schematically. Further, FIG. 2 is an external perspective view of the particulate filter 1. As shown in these figures, according to this embodiment,
The reproduction section of the filter body 2 is divided into a plurality of areas A, B, C, and D about the point O in a substantially concentric pattern. Therefore, as the reproduction area is divided into substantially concentric circles, the electric heaters 3 are also electrically divided from the electric heaters in the areas adjacent to each other and wired in a ring shape. And each electric heater wire 3
One of the terminals a, 3b, 3c, and 3d is connected to the battery 5 of the mounted vehicle via the heater relay 4 that constitutes a control means for sequentially energizing the electric heater wires, and the other terminal is grounded. It The heater relay 4 is driven by a control circuit (ECU) 6 which constitutes the control means.

FIGS. 3 (a), (b), and (c) show one operation example of the particulate filter 1 described above with time.

That is, FIG. 3 (a) shows the electric heater wire 3a wired in the area A.
The state where the particulate matter trapped in the same area A is ignited by energizing the device and starts to generate heat is shown. or,
FIG. 6B shows a state in which the regeneration processing of the area A has already been completed and the electric heater wire 3b wired in the adjacent area B is energized. In this state, the combustion heat regenerated by the particulate combustion in the area A is radially transferred to the area B, and is effectively utilized for the particulate ignition in the area B. That is, the amount of electric power supplied to the electric heater 3b can reach the particulate ignition point with a smaller amount than that to the electric heater 3a.

Further, FIG. 3 (c) shows a state in which energization to the electric heater 3d is completed and this time energization to the electric heater 3c is started. In this state as well, the combustion heat is similarly transferred from the region B to the region C, and although not shown, the region D
There is combustion heat transfer in the region C even during regeneration, and the same effect is expected.

As described above, according to the present embodiment, the regeneration section of the particulate filter 1 is concentrically divided, and the heater relay 4 controlled by the ECU 6 sequentially regenerates the particulate filter 1 from the center to the outside. As a result, it is possible to effectively use the heat generated in the regeneration section that has been subjected to the regeneration process before, and thus it is possible to reduce the amount of power for filter regeneration.

As described above, in this embodiment, the filter is regenerated from the center to the outside. This is because the central part is the most likely to ignite particulates, and the outer part that is relatively difficult to ignite It is intended to utilize the heat of combustion of the regenerated part. However, as another embodiment, the heater relay 4 may be operated so that the regeneration section is sequentially regenerated from the regeneration section of the outer peripheral portion toward the central section. It is higher than that of the conventional particulate filter. This is because in the case of the fan-shaped regeneration section, the combustion heat of one regeneration section is dispersed not only to the next regeneration section but also to other regeneration sections.

Further, in the illustrated embodiment, the division ratio of each reproduction section is
Basically, the outer radii Ra, Rb, Rc, Rd (see FIG. 1) of each regeneration segment are 2πRa ² = πRb ² , that is, Rb =, so that the filter cross-sectional area shown in FIG. 1 is equally divided. ▲ √ ▼ Ra Below, similarly, the electric heater wires 3a to 3d may be wired by dividing so as to satisfy the relationship of Rc = ▲ √ ▼ Ra and Rd = 2Ra, but as described above, it is relatively In order to improve the ignitability of the outer peripheral portion where it is difficult to ignite, even if the electric heater wire lengths are made equal and the amount of heat generation is made equal, and the areas of the regions are divided in the order of A>B>C> D. good.

[Advantages of the Invention] As described above, according to the present invention, the electric power consumption of the electric heater associated with the regeneration can be reduced more than before by effectively utilizing the combustion heat of the previously regenerated section. Also, due to the concentric division of the regeneration section, the heat of combustion in the regeneration section is evenly transferred to the next regeneration section because the combustion heat of the regeneration section is evenly transmitted to the next regeneration section, and the temperature distribution in the section becomes uniform, causing local cracks. Can be prevented. Further, along with this, the particulates are uniformly burned, and the problem that exhaust gas does not easily flow in a certain portion after the filter regeneration is eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of a particulate filter showing one end surface of a filter body according to the present invention; FIG. 2 is an external perspective view of the filter body shown in FIG. 1, FIGS. 3 (a), (b),
FIG. 4C is a diagram showing the regeneration state of the filter with time;
The figure is a view showing a heat transfer state of a regeneration section of a conventional particulate filter and one regeneration section. 1 ... Particulate filter, 3a-3d ... Electric heater wire, 4 ... Heater relay, 6 ... Control circuit (EUC), A, B, C, D
… Region (playback category).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Sami Creator Hiroyuki Sami 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (56) Reference JP-A-63-57809 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A cylindrical particulate filter for collecting solid particles in exhaust gas discharged from a diesel engine, which corresponds to a substantially concentrically divided filter regeneration section near one end face of a particulate filter body. When the filter is regenerated, the electric heater wire placed in the regeneration section outside the filter is replaced with the electric heater wire placed in the regeneration section in the center of the filter when the filter is regenerated. Or a control means for sequentially energizing the electric heater wire arranged in the regeneration section inside the filter from the electric heater wire arranged in the regeneration section on the outer periphery of the filter.