JPS6140893Y2 - - 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 the electric heating element to a filter member, in which clogging caused by the electric heating element is eliminated by heating the electric heating element.

Generally, the exhaust gas of a diesel engine contains a large amount of particulate components (particulate matter) such as carbon particles. As an exhaust purification device that purifies the exhaust gas by preventing these particulate components from being released directly into the atmosphere,
Conventionally, it 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 an open end on the upstream side and the rest are open on the downstream side. A filter member whose ends are each closed by a blind plug is disposed in the exhaust passage of the engine, and particulate components in the exhaust gas are collected by the partition wall while the exhaust gas passes through the filter member. things are well known.

However, in engines equipped with such a filter member, when the engine is operated for a long period of time, the filter member becomes clogged due to the accumulation of particulate components, and the exhaust pressure of the engine increases, 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. By energizing the electric heating element when the filter member becomes clogged or when the filter member becomes clogged, the particulate components deposited on the filter member are heated and burned, thereby regenerating the filter member. something is proposed.

However, when considering the distribution of the particulate components deposited on the filter member, it is found that the particulate components are collected by the partition walls of the small holes of the filter member while passing through the partition walls, so the upstream part of the filter member is thicker and the part downstream 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.

In addition, in the above 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 object of this invention is to make the electric heating element concentrated, thereby making it easier to fix the electric heating element and improving the regeneration efficiency of the filter member.

In order to achieve this purpose, the configuration of the present invention is such that a large number of small holes extending axially through the partition wall having air permeability are formed, and some of the small holes have an open end on the upstream side. The remaining part is an engine exhaust purification device in which a filter member whose downstream open end is closed by a blind plug is disposed in the engine exhaust passage, and electric heat is generated in the blind plug that closes the upstream open end of the small hole. Set up your body,
The electric heating element heats and burns the particulate components deposited on the filter member to regenerate the filter member.

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 ends of some of them are closed, and the downstream open ends of the rest are closed with blind plugs 7, 7, ... and 8, 8, ... made of heat-resistant cement, etc., and the upstream ends are open. small holes 6b, 6
After the exhaust gas flowing in from b, ... passes through the partition walls 6a, 6a, ..., small holes 6b, 6 whose downstream ends are open are formed.
b,..., between which the partition walls 6a, 6
A,... are designed to collect particulate components in the exhaust gas.

In the filter member 6, the small holes 6
Some blind plugs 7, 7, ... that close the upstream open ends of b, 6b, ... have smaller holes 6 than others.
The extended blind plugs 7, 7, .
is inserted into each small hole 6b in a bent manner, and is fixed with its bent end protruding further back than the blind plug 7.

Furthermore, both ends of the electric heating element 9 are insulated by insulating members 10, 10 and drawn out to the outside of the exhaust passage 4, and one end is grounded,
The other end is connected to a battery 12 via a relay 11. Further, a control circuit 13 is connected to the relay 11, and the control circuit 13 detects the mileage of the automobile, the operating time of the engine 1, the clogging state of the filter member 6, etc., and outputs a detection signal. The sensor 14 is input-connected to a correction circuit 15 that detects the exhaust temperature, load condition, rotation speed, etc. of the engine 1 and outputs a correction signal, and the detection signal from the sensor 14 and the correction signal from the correction circuit 15 Based on this, the control circuit 13 is activated to control the opening and closing of the relay 11 to energize or stop energizing the electric heating element 9 at every predetermined mileage or constant driving time, or when clogging reaches a predetermined state. It is configured. Note that the above correction signal is for canceling the signal from the sensor 14 when the exhaust gas temperature rises above the temperature required for self-combustion of carbon when energizing is carried out every fixed mileage or fixed driving time, for example. In addition, devices that detect clogging based on increases in exhaust pressure compensate for changes in exhaust pressure due to rotation and load fluctuations, and devices that detect clogging based on changes in electrical resistance due to carbon deposition correct for changes in exhaust pressure caused by changes in temperature. This is to correct the change in resistance value due to Note that 16 is an insulating plate that prevents the portions (bent portions) inserted into each small hole 6b of the electric heating element 9 from coming into contact with each other and causing a short circuit.

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

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 14 detects this and outputs a detection signal, and this detection signal causes the control circuit 13 to operate based on the correction signal from the correction circuit 15, and the relay 11
When the relay 11 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. This corresponds to a wide area up to a predetermined distance away from the area where a large amount of particulate components are deposited, and thus improves the regeneration efficiency of the filter member 6 by intensively heating the deposited particulate components. be able to.

Further, since the electric heating element 9 is fixed by the blind plugs 7, 7, . . . which are commonly used, the electric heating element 9 can be easily fixed to the filter member 6 without requiring any separate member.

In addition, in the above embodiment, the blind plug 7,
The electric heating element 9 is fixed to the blind plug 7, . . . in such a way that its bent tip protrudes further back than 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. This is achieved by providing an electric heating element for heating and burning the accumulated particulate components in the blind plug that closes the upstream open end of the small hole of the filter member that collects the particulate components in the engine exhaust gas. , the electric heating element can be fixedly supported on the filter member using the existing blind plug, and the heating range can be expanded by inserting the electric heating element deep into the small hole. This makes it possible to facilitate the fixation of the body and improve the regeneration efficiency of the filter member.

[Brief explanation of the drawing]

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, 13... Control circuit, 14... Sensor, 15
...Correction circuit.

Claims (1)

[Scope of utility model registration request] 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. An engine exhaust gas purification device comprising a member disposed in an exhaust passage of the engine, characterized in that an electric heating element is provided in a blind plug that closes the upstream open end of the small hole.