JPH0437247B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for collecting and incinerating particulates discharged from a diesel engine, and more particularly to an electrode structure of a heater in such a device.

Conventional technology A trap for purifying particulate matter (particulate matter) discharged from a diesel engine
A heater is provided in front of the trap container, and the heat from the heater incinerates the particulates collected in the trap material. In this case, the heater is placed at the front end of the trap, perpendicular to the flow of exhaust gas. This heater is made of nichrome wire or the like, but because of its large power consumption, the heater is divided into a plurality of heater wires so that only the necessary number of heater wires are used. In this case, the heater wires are angularly distributed, their inner ends connected to a common ground terminal, and their outer ends connected to respective power terminals located centrally at one location outside the trap vessel. wired. in this way,
The reason why the power terminals for each heater wire are concentrated in one place is to make it easier to route the lead wires from the battery to the terminal, and to provide a single terminal cover. But in this case,
If each heater wire were to be extended to the corresponding power supply terminal, the length of each heater wire would be different, which would change the power consumption and heat generation amount of each heater wire. Therefore, it becomes difficult to obtain stable particulate ignitability. In addition, if you try to match the power consumption of each heater wire, you will have to make different cross-sectional areas of the heater wires, which will require multiple heater wire materials, and the processing dimensions of the heater wire support members will have to be different. Failure to do so may occur.

OBJECT OF THE INVENTION An object of the present invention is to make the power consumption of each heater wire the same while using the same material for each heater wire. The object of the present invention is to provide a structure of a split type heater.

Structure of the Invention In the particulate purifier heater for a diesel engine of the present invention, a heater is arranged in a trap container on a surface intersecting the flow of exhaust gas, and the heater is formed by a plurality of meandering heater wires divided in an angular direction. The inner ends of each heater wire are connected to a common ground terminal, and the outer ends are connected to respective power terminals provided centrally in one location of the trap container via respective connecting conductors. The conductors are constituted by conductive strips located along the outer periphery of the heater.

Embodiment The following description will be made with reference to the drawings. In FIG. 1, 10 is a trap case, 12 is a trap front case, and their flange portions are fastened together by bolts 14. Reference numeral 16 denotes a trap material, which is placed inside the trap case. Exhaust gas from the diesel engine comes from the exhaust pipe 18 at arrow A
The particulate components are introduced into the trapping material 16 through the front case 12 and collected. The exhaust gas from which the particulate components have been removed is taken out from the case 10 to the exhaust pipe 20 as shown by arrow B.

A heater 22 is arranged in front of the trap so as to be perpendicular to the flow of exhaust gas. This heater 22
As shown in FIG. 2, six heater wires 24-1 are arranged in a fan-shaped area divided into six equal parts in the angular direction on a plane perpendicular to the flow of exhaust gas.
24-2, 24-3, 24-4, 24-5, 24
- Consists of 6. These heater wires are connected to the heater board 26
It is attached to the top as described below. Heater board 26
consists of a circumferential portion 261, six heater support portions 262 extending in the radial direction from the circumferential portion 261, and a central portion 263 where the heater support portions 262 converge. Circumferential portion 261 is secured to circumferential shoulder 121 (FIG. 1) of front housing 12 by bolts 30, thereby holding the heater assembly in position. Furthermore, six windows 32 are formed between the circumferential portion 261, the radial support portion 262, and the central portion 263, allowing exhaust gas to freely flow therethrough.

Six heater wires 24-1, 2, 3, 4, 5, 6
are arranged in a meandering manner and are held electrically suspended from the heater board 26 by the following means.
That is, as shown in FIG. 3, a block 34 made of an insulator such as ceramic is attached to the radial support portion 262 of the heater substrate 26 by rivets 36 or the like. Heater wires 24-1, 2, 3, 4,
5 and 6 are folded back on this block (see the dashed line in Figure 2 for 24-2).
A meandering shape is formed. As shown in FIG. 3, an insulator 38 having a chevron-shaped cross section is placed on the block with its convex portion facing downward, electrically insulating adjacent heater wires from each other. Further, an insulator 39 is provided between adjacent blocks 34 to prevent the heater wire from sagging.

A cylindrical ground electrode 42 is fixed on the center portion 263 of the heater board 26, and each heater wire 24-1,
The inner ends 24' of 2, 3, 4, 5, and 6 are connected by brazing or the like. In FIG. 2, 50 is a power terminal unit, which includes an insulator 52, an insulator holding fitting 54, and six power terminals 56-1, 56-2, 56-3, and 56 inserted through the insulator 52.
-4, 56-5, 56-6.

According to the invention, power terminals 56-1, 2,
Heater wires 24-1 corresponding to 3, 4, 5, and 6,
It has the following structure to connect to 2, 3, 4, 5, and 6. That is, power terminals 56-1 and 56-6 are directly connected to heater wires 24-1 and 24-6 close to power terminal unit 50. On the other hand, the heater wires 24-2, 3, 4, and 5 located away from the power supply terminal unit 50 are connected with conductive strip plates 70-2, 3, 4, and 5 interposed therebetween. This conductive strip is made of a heat-resistant conductor, and its width, which determines its electrical resistance, is such that the voltage drop that occurs across the strip when the heater is energized can be almost ignored. For example, the ratio of the specific resistance of the conductive strip to the specific resistance of the heater wire is 57%, and the cross-sectional area of the heater wire is 2.7 times that of the conductive strip. In this case, the power consumed by the conductive strip can be reduced to one-fifth of the power consumed by the extended portion of the heater wire if it were extended directly to the corresponding terminal.

Among the conductive strips, 70-2 and 70-3 are supported floating from the ground by the structure shown in FIG. 4 (this is the same for 70-4 and 70-5, but they are symmetrical). That is, 72 is the adjacent strip 7
It is a first support that supports 0-2 and 70-3 or 70-4 and 70-5 while electrically insulating them from each other, and 74 is a strip plate 70- that goes to the farthest heater wire.
4 or 70-5. In the embodiment of FIG. 4, each first support 72 includes a
As shown in FIG. 5B, it consists of an electrode guide insulator 76 made of two insulators with a chevron-shaped cross section and a stopper band 77. The guide insulator 76 has a pin-shaped projection 762 on its outer surface opposite to the mating surface with the groove 761, while the stop band 77 has a pin-shaped projection 762.
As shown in FIG. 5B, the two insulators 76 are wound around a band 77 with their inner surfaces 764 aligned, and the band 77 is wrapped around the circumference of the heater board 26. It is fixed by brazing or the like at 773 on 261. Prior to that,
The conductive strips 70-2 and 70-3 (or 70-4 and 70-5) are connected to the groove 761 of the insulator 76 as shown in FIG.
It goes without saying that you must pass the exam through.

On the other hand, regarding the second support 74 that supports the conductive strip 70-3 or 70-4, the 6A
As shown in FIGS. 6B and 6B, this support 74 consists of a pawl portion 79 that is integrally bent from the circumference 261 of the heater substrate 26. As shown in FIG. A first washer 80 and a second washer 81 made of an insulator are inserted into the hole 70' formed in the strip plate 70-3 or 70-4 from both sides, and the screw 82 is inserted into the hole 80' of the washer 80, 81.
It is fitted into the hole 79' of the pawl part 79 via 81'.
Thereby, the strip plate 70-3 or 70-4 can be held in an electrically floating state with respect to the heater board 26.

After attaching the strip plates 70-2, 3, 4, and 5 in this way, these heater wires 24-1, 24
-6, corresponding terminals 56-1,
2, 3, 4, 5, and 6, respectively. That is, as shown in FIG. 4, one end of each strip plate is inserted into a groove 56' at the end of the terminal, and the other end has a groove 70'', and the heater wire corresponding to this groove 70'' is inserted into the groove 56' at the end of the terminal. Connected.

Figures 7A and 7B show two adjacent strips 7.
This is another embodiment of the first support 72 that supports 0-2, 70-3, or 70-4 and 70-5. In this embodiment, the protrusion 762 in FIGS. 5A and 5B,
Instead of the hole 771, the electrode guide insulator 76 has a groove 76 on its outer surface opposite the mating surface, which is equal to the width of the band.
6, and the band 77 just fits into this groove 766. Therefore, it is prevented from coming off from the electrode guide insulator band 77.

FIGS. 8A and 8B show still another embodiment of the first support 72. FIG. In this case, the band 77 shown in FIGS. 5A, 5B, or 7A, 7B is omitted, and instead, the claw portion 85 is integrally formed upright from the heater substrate, while the electrode guide insulator 76 having a chevron-shaped cross section is a hole 767 that passes through the central protrusion.
have. The rivet 87 is inserted into the hole 767 with the band plates 70-2, 70-3 (or 70-4, 5) passed through the groove 761 formed on the mating surface of the electrode guide insulator 76, and the hole of the pawl part 85 is inserted. 85'.

Figures 9A and 9B show strip plates 70-3 and 70-4.
Another embodiment of the second support 74 is shown. The support 74 is a strip plate 70-3 (or 70-
4) A holding plate 90 made of an insulator having a U-shaped channel 901 in cross section with a height dimension that exactly fits with the holding plate 90, and a rectangular plate having a width slightly smaller than the width in the height direction of the inner channel 901 of this holding plate 90. 91. The rectangular plate 91 is fitted to the holding plate 90 via the band plates 70-3 and 70-4, and the rivets 94 are inserted into the holes 91' of the rectangular plate 91, the holes 70' of the band plates 70-3 and 70-4, It fits into the hole 85' of the pawl 85 through the hole 90' of the holding plate 90. The holes 70' in the strips 70-3 and 70-4 have sufficient dimensions so as not to come into contact with the rivets 94, thereby providing electrical insulation.

Effects of the Invention In the present invention, the heater wire 70 separated from the terminal
-2, 3, 4, 5 heat resistant conductive strip 24-
By connecting wires 2, 3, 4, and 5, the voltage drop in these parts can be virtually eliminated, so even if each heater wire is made of the same material, the amount of heat generated can be made the same. . This, together with the fact that the processing dimensions of the heater supports 34 and 38 can be made common, makes it possible to reduce manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a schematic axial sectional view of the particulate purification device of the present invention, FIG. 2 is a front view of the heater of the present invention seen from the - line in FIG. 1, and FIG. 4 is a perspective view showing essential parts of the electrode structure of the present invention; FIGS. 5A and 5B are an exploded perspective view, an assembled perspective view, and an assembled perspective view of the first support shown in FIG. 4, respectively; Figures 6A and 6B are an exploded perspective view, an assembled sectional view, and Figures 7A and 7 of the second support in Figure 4, respectively.
Figure B shows the respective fifth parts of the second embodiment of the first support
Figures 8A and 8B, which are similar to Figures A and 5B, are the same figures as Figures 5A and 5B in the third embodiment of the first support, respectively.
Figures 9A and 9B are similar to Figures 5B and 6A and 6B in the second embodiment of the second support.
A figure similar to figure B. 10... Trap case, 12... Trap front case, 16... Trap material, 22... Heater, 24-1, 2, 3, 4, 5, 6... Heater wire, 56-1, 2, 3, 4, 5, 6... Power terminal, 70-2, 3, 4, 5... Conductive strip plate.

Claims (1)

[Claims] 1 A heater is placed in the trap container at the end of the surface of the trap material that intersects with the flow of exhaust gas, and the heater consists of a plurality of angularly divided heater wires in a meandering arrangement, and each heater wire is The ends are connected to a common ground terminal, and the outer ends are connected to respective power terminals that are concentrated in one place in the trap container, and the heater wires away from the power terminals are connected along the outer circumference of the heater. A heater structure of a particulate purifier for a diesel engine, which is connected to a corresponding power supply terminal by means of a located conductive strip.