JPH07332068A - Exhaust emission control device of diesel engine - Google Patents

Abstract

PURPOSE:To enable damage generated caused by thermal distortion to be prevented by individually regenerating filters also in the operation of a diesel engine, and enabling the filters to be uniformly held to the relative low temperature. CONSTITUTION:A plurality of gas passages respectively provided with dampers are formed in a main body 8 wherein a gas inflow part 6 for introducing exhaust gas G of a diesel engine is provided on one end, while an exhaust port 7 is provided on the other end, and filters 11a, 11c housing heaters 5a, 5c are arranged in respective gas passages, and at least one gas passage 10a or 10c is closed by dampers 12a to 12d, and the filters in the gas passages are heated by the heaters, so as to burn trapped matters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for a diesel engine, and more particularly to an exhaust gas purifying apparatus for a diesel engine suitable for a relatively small diesel engine used in automobiles and cogeneration equipment. .

[0002]

2. Description of the Related Art Conventionally, in construction machines such as dump trucks, power shovels, truck mixers, buses, large trucks, etc., or stationary cogeneration equipment, a relatively small diesel engine is often used from the viewpoint of fuel consumption. . By the way, in this diesel engine, unburned substances such as soot exist as fine particulate matter in the exhaust gas during operation, and since the discharge of this particulate matter is not environmentally preferable, it can be collected by the purifying device. Has been done.

There is a trap system as one structure of the exhaust gas purifying device of the diesel engine. In this system, exhaust gas is passed through a main body that houses a honeycomb filter with a catalyst made of ceramic, and the particulate matter is captured by this filter. When this purifying apparatus is used for a long time, the filter is clogged, the back pressure becomes high, the operating efficiency of the diesel engine is lowered, and the particulate matter cannot be sufficiently captured. Therefore, after a lapse of a predetermined time, it is heated by a burner or an electric heater (about 400 ° C.), and the collected particulate matter is burned to be regenerated.

[0004]

By the way, the conventional diesel engine exhaust gas purifying apparatus has the following problems. That is, one in one body forming the purification device
Because it only contains one filter, the diesel engine must either be shut down or the exhaust gas bypassed during filter regeneration, which not only limits regeneration but also burner or Heating with an electric heater causes local heating, and there is a problem that the filter may be damaged due to thermal strain.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has a gas inlet for introducing exhaust gas of a diesel engine at one end and the exhaust gas at the other end. A plurality of gas passages each having a damper are formed in a main body having a gas discharge port, a filter having a built-in heater is disposed in each gas passage, and at least one of the plurality of gas passages is formed. An exhaust gas purifying apparatus for a diesel engine, in which a gas passage is closed by the damper and a filter in the gas passage is heated by a heater to burn a trapped substance.

[0006]

[Operation] According to the exhaust gas purifying apparatus for a diesel engine of the present invention, a predetermined gas passage is closed by a damper among a plurality of gas passages, and a filter arranged in the gas passage is built in. Since the trapped substance is burned by being heated by the heater provided, it can be regenerated even during the operation of the diesel engine, and the local heating of the filter is eliminated, so that there is no fear of damage due to thermal strain.

[0007]

EXAMPLE An example of an exhaust gas purifying apparatus for a diesel engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an exhaust gas purifying apparatus for a diesel engine. Reference numeral 1 is a purifier, and an exhaust gas G is introduced from a diesel engine 2 through an exhaust gas line L. A temperature detector 3 is attached to the exhaust gas G supply portion of the purifier 1, and this signal V is given to the temperature controller 4 so that the heating temperature by the heater 5 is controlled as described later. .

FIG. 2 is an enlarged side view of the purifier 1, and FIG. 3 is a plan view. This purifier 1 has a plurality of gas passages 10a to 10d (in this embodiment, 4) which are divided vertically and horizontally by a partition wall 9a, 9b into a rectangular tubular main body 8 having an inlet 6 and an outlet 7 for the exhaust gas G. Individual gas flow channels 10a-10
Heaters 5a to
Filters 11a to 11d having a built-in 5d are arranged.

Dampers 12a to 12d are provided on the exhaust side of the gas flow paths 10a to 10d, respectively.
The dampers 12a to 12d are operated by a controller (not shown) so that at least one of them is closed after a predetermined time (a time during which the trapped substance in the exhaust gas is accumulated to some extent). Each of the filters 11a to 11d is a ceramic honeycomb structure, and the inside is divided into a honeycomb shape to form a unit body, and a heater is wound around the outer peripheral wall surface of the unit body to form a filter. An electric circuit is configured so that each can be heated.

In the exhaust gas purifier of the diesel engine having the above structure, the particulate matter such as soot contained in the exhaust gas G is now sufficiently collected in the filter 11a arranged in the gas passage 10a. If so, since the filter 11a needs to be regenerated, the purifier 1 is operated as follows. First, by operating the damper 12a provided at the outlet of the filter 11a, the gas passage 10a
To close. At this time, the exhaust gas G passes through the other gas flow path 10
It flows through the inside of b to 10d, is purified by the filters 11b to 11d provided in this flow path, and is discharged from the discharge port 7.

A heater 5a provided on a filter 11a in a gas flow passage 10a closed by a damper 12a.
Is heated by energization, but the signal V is given to the temperature controller 4 while the temperature of the filter 11a is detected by the temperature detector 3, and the temperature in the gas passage 10a is necessary for combustion of the particulate matter. The filter 11a is heated to a temperature of, for example, about 400 ° C.

As described above, since the heater 5a is built in the filter 11a so that the heating temperature becomes uniform, the local heating of the filter 11a can be prevented. When the combustion of the combustible particulate matter such as soot collected in the filter 11a is completed and regenerated in this manner, the damper 12a is opened and, if necessary, the gas passages 10b to 10n 10
Any one of d is reproduced by the same operation as described above.

In the present embodiment, the gas passage 10 is formed by partitioning the inside of the rectangular tube-shaped main body 8 by partition walls 9a and 9b vertically and horizontally.
Four a to 10d are formed, and a damper 1 is provided on the gas outlet side.
Although the case where 2a to 2d are provided has been described, these can be appropriately changed.

[0014]

As is apparent from the above description, the exhaust gas purifying apparatus for a diesel engine according to the present invention has a gas inlet for introducing the exhaust gas of the diesel engine at one end and an exhaust gas outlet for the exhaust gas at the other end. A plurality of gas flow paths each having a damper are formed in the main body, a filter having a built-in heater is arranged in each gas flow path, and at least one gas flow path of the plurality of gas flow paths is provided in the damper. The filter in the gas flow path is heated by a heater to burn the trapped substance.

Therefore, not only can the filters be individually regenerated even during operation of the diesel engine, but also the filters can be maintained at a relatively low temperature and evenly, so that damage due to thermal strain can be prevented. The effect is that you can.

[Brief description of drawings]

FIG. 1 is a schematic part of an exhaust gas purification device for a diesel engine.

FIG. 2 is a side view of the purifier.

FIG. 3 is a plan view of a purifier.

[Explanation of symbols]

1 Purifier 2 Diesel Engine 3 Temperature Detector 4 Temperature Controller 5 Heater 6 Inlet 7 Discharge Port 8 Main Body 9a, 9b Partition Walls 10a-10d
Gas channel 11a-11d Filter 12a-12d
Damper

Claims (2)

[Claims] 1. A plurality of gas flow paths each having a damper are formed in a body having a gas inlet for introducing exhaust gas of a diesel engine at one end and an exhaust gas outlet for the exhaust gas at the other end, and each of the gas passages is formed. A filter containing a heater is arranged in the flow channel, at least one gas flow channel of the plurality of gas flow channels is closed by the damper, and the filter in the gas flow channel is heated by the heater to collect the substance. Exhaust gas purifying device for diesel engines that burns fuel. 2. The exhaust gas purifying apparatus for a diesel engine according to claim 1, wherein the heater is an electric heater and the filter is a ceramic filter.