JPS6140899Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an engine exhaust purification device, and in particular, a honeycomb-shaped filter member for collecting particulate components in exhaust gas is disposed in an exhaust passage, and the particulate components on the filter member are deposited. The present invention relates to a structure for attaching an electric heating element to a filter member, in which clogging caused by clogging is eliminated by heating the electric heating element.

Generally, diesel engine exhaust contains a large amount of particulate components (particulate matter) such as carbon particles, and conventional exhaust purification devices are used to prevent these particulate components from being released into the atmosphere. , has a honeycomb shape in which a large number of small holes extending through it in the axial direction are formed by an air-permeable partition wall made of ceramics, etc., and some of the small holes have open ends on the upstream side, and the rest have open ends on the downstream side. A filter member, each of which is blocked by a blind plug, is arranged in the exhaust passage of the engine,
It is well known that particulate components in the exhaust gas are collected by the partition wall while the exhaust gas passes through the filter member.

However, in engines equipped with such a filter member, if the engine is operated for a long period of time, the filter member will become clogged due to the accumulation of particulate components, and the exhaust pressure of the engine will increase, resulting in a decrease in output. There is the problem of inviting.

For this reason, conventionally, as disclosed in, for example, Japanese Unexamined Patent Publication No. 55-131518, an electric heating element made of nichrome wire or the like is attached to the downstream end of the filter member by adhering it with a heat-resistant adhesive. or when the filter member becomes clogged, the electric heating element is energized to heat and burn the particulate components deposited on the filter member, thereby regenerating the filter member. is proposed.

However, when considering the distribution of the particulate components deposited on the filter member, the upstream part of the filter member is thicker and the downstream part is It accumulates so that the side parts become thinner. Therefore, in the above proposal, since the electric heating element is disposed at the downstream end of the filter member, the regeneration efficiency of the filter member is low.

Further, in the above-mentioned proposal, since the electric heating element is bonded to the end face of the filter member, an adhesive is required and the electric heating element easily peels off, making it difficult to fix the electric heating element to the filter member.

Therefore, in view of these points, the present invention utilizes a blind plug that closes the open end on the upstream side of the small hole of the filter member, and by providing an electric heating element in the blind plug, the electric heating element is connected to the filter member. In addition to making it possible to fix it without requiring a separate member, the electric heating element is inserted deep from the upstream end of the small hole to widen the heating range and increase the heating effect on the particulate components deposited in the upstream part. The main purpose of this is to make it easier to fix the electric heating element and to improve the regeneration efficiency of the filter member.

By the way, when inserting the electric heating element into the small hole of the filter member while fixing it with a blind plug, the diameter of the small hole of the filter member is extremely small (for example, 3 mm), and the wire diameter of the electric heating element is also very small. If the diameter is small (for example, 0.7 mm), there is a risk that the electric heating element may be short-circuited within the small hole during assembly.

In addition, in order to expand the heating range and improve heating efficiency, it is necessary to place the electric heating element deep inside the small hole (for example, 30
In contrast, the length of the blind plug needs to be as short as possible (for example, 3 mm) in order to improve the collection efficiency of the filter member. Due to the difference, the amount of protrusion of the electric heating element to the rear side from the blind plug becomes longer. As a result, there is a risk that the protruding portions of the electric heating elements may come into contact with each other due to vibrations of the automobile, resulting in a short circuit.

Therefore, a further object of the present invention is to interpose an insulating plate fixed with a blind plug between the opposing parts of the approximately U-shaped electric heating element inserted into the small hole of the filter member. This reliably prevents short-circuiting of the electric heating element when the electric heating element is turned on or when the car vibrates while driving.

In order to achieve these objectives, the structure of the present invention is as follows:
A large number of small holes extending through the air-permeable partition wall in the axial direction are formed, and the upstream open ends of some of the small holes are closed by blind plugs, and the downstream open ends of the remaining holes are closed by blind plugs. In an engine exhaust purification device comprising a member disposed in an engine exhaust passage, an electric heating element fixed by the blind plug and inserted into the small hole is provided,
The electric heating element is formed into a substantially U-shape consisting of a pair of straight parts and a curved part connecting the tips of the straight parts, and an insulating plate fixed with the blind plug is provided between the pair of straight parts. By providing a structure in which the filter member is provided with, the electric heating element inserted into the small hole of the filter member is kept insulated.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In FIGS. 1 to 5, 1 is a four-cylinder diesel engine equipped with four cylinders 1a, 1a, . 4 is an exhaust passage for discharging exhaust gas from the engine 1; 5 is a fuel injection pump for injecting and supplying fuel into each cylinder 1a of the engine 1;

A filter member 6 is disposed in the middle of the exhaust passage 4 to collect particulate components (particulate matter) such as carbon particles in the exhaust gas. That is,
The filter member 6 includes partition walls 6a, 6 having air permeability.
It is made of honeycomb-shaped ceramics or the like in which a large number of small holes 6b, 6b, . The upstream open end of the part is closed, and the downstream open end of the remaining part is closed with blind plugs 7, 7, . . . and 8, 8, . , 6b, . . . After passing through the partition walls 6a, 6a, . . ., the exhaust gas flows into the small holes 6b, 6b, . It is designed to collect particulate components.

Further, in the filter member 6, the small holes 6b,
Some of the blind plugs 7, 7, ... that close the upstream open ends of the small holes 6b, ... are extended by a predetermined length toward the inner side (downstream side) of the small hole 6b than the others, and the extended blind plugs At 7, 7, ..., an electric heating element 9 made of a continuous nichrome wire or the like is inserted into each small hole 6b in a bent manner, and the bent end is inserted deeper than the blind plug 7. It is fixed by the blind plug 7 while protruding to the side. That is, the electric heating element 9 inserted into each small hole 6b has a pair of opposing linear portions 9a, 9a, as shown in enlarged detail in FIGS. 4 and 5.
and a curved portion 9b connecting the tips of the straight portions 9a, 9a.
Moreover, it is disposed in the diagonal direction of one of the small holes 6b having a substantially square cross section. And the electric heating element 9
There is an electric heating element 9 between the opposing straight parts 9a, 9a.
Insulating plate 10 oriented in another diagonal direction orthogonal to
is fitted and fixed by the blind plug 7, so that the U-shaped electric heating element 9 and the insulating plate 10 are arranged diagonally in the small hole 6b.

Further, both ends of the electric heating element 9 are insulated by insulating members 11, 11 and drawn out to the outside of the exhaust passage 4, and one end is grounded,
The other end is connected to a battery 13 via a relay 12. Further, a control circuit 14 is connected to the relay 12, and the control circuit 14 includes a sensor that detects the mileage of the automobile, the operating time of the engine 1, the clogging state of the filter member 6, etc., and outputs an activation signal. 15 and a correction circuit 16 that detects the exhaust temperature, load condition, rotation speed, etc. of the engine 1 and outputs a correction signal. The control circuit 14 operates to control the opening and closing of the relay 12 to energize or stop energizing the electric heating element 9 at every predetermined mileage or predetermined driving time, or when clogging reaches a predetermined state. It is configured. Note that the above correction signal cancels the signal from the sensor 15 when the exhaust temperature rises above the temperature necessary for self-combustion of particulate components, for example, when energization is performed every fixed mileage or fixed driving time. In addition, when clogging is detected due to an increase in exhaust pressure, it compensates for changes in exhaust pressure due to changes in rotation speed and load, and it also detects clogging based on changes in electrical resistance due to carbon deposition. In this case, the change in resistance value due to temperature is corrected.

Therefore, in the embodiment described above, as the engine 1 is operated, the particulate components in the exhaust gas are collected on the filter member 6 with a deposition distribution such that they are thickly deposited on the upstream portion of the filter member 6, and the exhaust gas is purified. It is discharged while being

Then, after a certain period of time has elapsed, when the filter member 6 becomes clogged due to the accumulation of particulate components,
The sensor 15 detects this and outputs an activation signal, and this activation signal activates the control circuit 14 based on the correction signal from the correction circuit 16, causing the relay 12 to
When the relay 12 is activated, the electric heating element 9 is energized and generates heat, thereby heating and burning the particulate components deposited on the filter member 6. the result,
The filter member 6 is unclogged and regenerated.

In that case, the electric heating element 9 is connected to the filter member 6.
are deeply inserted into the small holes 6b, 6b, ... from the open end on the upstream side and are fixedly supported by the blind plugs 7, 7, ..., so that the heating range is from the upstream end of the filter member 6 to the downstream side thereof. The part of the filter member 6 that is located a predetermined distance away from the filter member 6 almost coincides with the area where a large amount of particulate components are deposited.
can improve regeneration efficiency.

Furthermore, since the electric heating element 9 is fixed by the commonly used blind plugs 7, 7, . . . , the electric heating element 9 can be easily and reliably fixed to the filter member 6 without the need for a separate member. .

Furthermore, since the insulating plate 10 is disposed between the opposing straight parts 9a, 9a of the electric heating element 9 inserted into the small hole 6b of the filter member 6, the electric heating element 9
There is no risk that the straight portions 9a, 9a of the electric heating element 9 will come into contact with each other when assembled to the filter member 6 or due to vibrations of the automobile, etc., thus ensuring that the electric heating element 9 is short-circuited. can be prevented.

Furthermore, the small holes 6b, 6 of the filter member 6
b, ... have a substantially square cross section, and the U-shaped electric heating element 9 and the insulating plate 10 are disposed diagonally in the small hole 6b having a substantially square cross section, so that the U-shaped electric heating element 9 Since the distance between the straight portions 9a, 9a can be increased, the workability of assembling the electric heating element 9 can be improved, and the heating efficiency of the electric heating element 9 can be improved.

In addition, in the above embodiment, the blind plug 7,
Although the electric heating element 9 was fixed to the blind plugs 7, 7, . It is possible to achieve the same effects as in the above embodiment.

As explained above, according to the present invention, the upstream open ends and the downstream open ends of a large number of axially extending small holes formed by an air-permeable partition wall are respectively blocked with blind plugs. Then, a U-shaped electric heating element for heating and burning the accumulated particulate components is fixed with the blind plug to the small holes of the honeycomb-shaped filter member that collects particulate components in the engine exhaust gas. By inserting the electric heating element into the filter member and disposing an insulating plate between the opposing straight parts of the electric heating element, the electric heating element can be fixedly supported on the filter member using an existing blind plug, and the electric heating element can be Since the heating range can be expanded by inserting the electric heating element deeply into the small hole, it is possible to easily fix the electric heating element and improve the regeneration efficiency of the filter member. Moreover, it is possible to reliably prevent short circuits caused by contact between the electric heating elements when assembling the electric heating elements or due to the vibrations of the automobile, etc., thereby stabilizing the regeneration of the filter member. This can be done by

Furthermore, if the small hole of the filter member is made into a substantially rectangular cross-section and a U-shaped electric heating element and an insulating plate are arranged in the diagonal direction of the small hole, the width of the electric heating element to be inserted can be increased. Therefore, it is possible to improve the ease of assembling the electric heating element and the heating efficiency.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is an overall system diagram, Fig. 2 is a vertical sectional view of the filter member, Fig. 3 is a partial front view of the filter member seen from the upstream side, and Fig. 4 5 is an enlarged view of the same part, and FIG. 5 is a cross-sectional view taken along the - line in FIG. 4. 1... Diesel engine, 4... Exhaust passage,
6... Filter member, 6a... Partition wall, 6b... Small hole, 7, 8... Blind plug, 9... Electric heating element, 9a... Straight part, 9b... Curved part, 10...
...Insulating plate, 14...Control circuit, 15...Sensor,
16...Correction circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A large number of small holes are formed that extend through the partition wall in the axial direction, and some of the small holes have an open end on the upstream side and the rest have an open end on the downstream side. An engine exhaust purification device comprising a filter member whose open end is each closed by a blind plug is disposed in the exhaust passage of the engine, an electric heating element fixed by the blind plug and inserted into the small hole, The electric heating element is formed into a substantially U-shape consisting of a pair of straight parts and a curved part connecting the tips of the straight parts, and an insulating plate fixed with the blind plug is provided between the pair of straight parts. A diesel engine exhaust purification device characterized by being provided with. (2) The small hole of the filter member has a substantially rectangular cross section, and the U-shaped electric heating element and the insulating plate are arranged in a diagonal direction of the small hole.Claim (1) of the Utility Model Registration Claim Exhaust purification device for the engine described.