JPH0519527Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust particulate separation device for treating particulates contained in the exhaust gas of an internal combustion engine.

(Prior art) In internal combustion engines, especially diesel engines,
The exhaust gas contains exhaust particulates whose main component is carbon, and to prevent them from being released into the atmosphere, a filter made of ceramic or the like is installed in the exhaust pipe to capture the particulates. . When these particulates accumulate, back pressure in the engine increases, which has an adverse effect on the engine. For this reason, measures are taken to burn and regenerate the particulates captured by the filter.

For example, as disclosed in Japanese Patent Application Laid-Open No. 60-204913, a filter element A having a catalyst that lowers the ignition temperature of carbon and promotes its incineration is shown.
A waste gas purification device is known that has a structure in which a filter element B and a filter element B having a catalyst that promotes the combustion of gaseous harmful substances are alternated several times with each other.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional device, the purifying device becomes hot as it is used, and there is a risk that the filter element may be damaged. That is, when exhaust gas flows through a plurality of filter elements A and B that are successively provided and each have a catalyst, heat generation occurs due to an oxidation reaction, and as a result of this heat being accumulated in sequence,
This is because the temperature of the downstream filter element may exceed a predetermined limit value.

Therefore, an object of the present invention is to provide an apparatus having a structure that does not reduce the purifying function or generate high heat even though it has a plurality of filter means.

(Means for solving the problem) A casing is provided in the middle of the exhaust pipe, and within the casing, a filter is arranged in which a heat-resistant catalyst-carrying portion supporting a catalyst and a non-catalyst-carrying portion are successively provided alternately. In addition, a heating device is provided upstream of the filter.

(Operation) Most of the particulates in the exhaust gas are captured by the first catalyst-supported part, and the remainder is captured by the subsequent catalyst-free part and catalyst-supported part. At the same time, harmful components in the exhaust gas are purified while flowing through each catalyst support section. At this time, reaction heat is generated and the catalyst supporting portion is heated. However, the non-catalyst-supported section at the next stage has a relatively low temperature because it does not have a catalyst and does not generate reaction heat, and is cooled when the exhaust gas flows through it. When the filter becomes clogged, the heating device is activated to heat the support section and incinerate the captured particles.

(Example) The exhaust particulate separator 1 shown in FIG. 1 includes a casing 2 provided in the middle of an exhaust pipe, a filter 3 provided within the casing 2, and a heating device 4 provided upstream of the filter 3. It consists of The casing 2 is made of a heat-resistant and corrosion-resistant material such as stainless steel and has a cylindrical shape, and is provided with conical connecting pipes at open ends on the diesel engine side and the muffler side (not shown).
The filter 3 is a so-called honeycomb-shaped or three-dimensional mesh-shaped filter made of ceramic, a heat-resistant material, and supports a catalyst such as a precious metal such as platinum or rhodium or a base metal in a certain width from the upstream side of the exhaust gas. A supporting portion 5 and then a non-catalyst supporting portion 6 made of ceramic material having the same width are provided alternately. This filter 3 is attached to the casing 2 via a cushion material such as steel wool. On the upstream side of the filter 3, a heating device 4 for a fuel burner including, for example, a fuel injection exit 42 is arranged. The heating device 4 is not limited to a fuel burner, and an electric heater may be provided immediately before the filter 3.

Particulates such as carbon generated by the operation of the diesel engine flow through the exhaust pipe along with the exhaust gas and are captured by the filter 3. When the filter 3 becomes clogged and the back pressure increases, the ignition plug 41 is heated in accordance with the instructions from the back pressure sensor 8, receives fuel from the fuel supply source, and injects it while atomizing it from the nozzle of the fuel injection 42. When ignited, the temperature of the catalyst support portion 5 of the filter 3 is set to a temperature at which the particulates begin to burn. Increase the temperature to about 450℃. After the temperature sensor 7 detects that the required temperature has been reached, the heating device 4 is stopped. The spark of the particulates that have started to burn due to the action of the catalyst burns and is transmitted to the particulates that continue without stopping on the outer wall of the filter 3. Catalyst-free portion 6
Then, the spark is transmitted from the entire surface of the adjacent catalyst supporting portion 5 and starts to burn the particulates. As the exhaust gas advances through the catalyst-free portion 6, it is cooled down, but when it reaches the next catalyst-supported portion 5, the catalytic action regains its combustibility. By repeating these cycles, all of the particulates captured by the filter 3 are burned and regenerated.

Note that when the exhaust gas reaches 450° C. or higher under high load, the heating device 4 is not operated, and self-combustion begins by the catalytic action of the catalyst support portion 5 of the filter 3 to regenerate the filter 3.

(Effects) As described above, the present invention provides a filter made of a heat-resistant material in the middle of the exhaust pipe, the filter is provided alternately in the catalyst-supported part and the non-catalyst-supported part, and a heating device is installed on the upstream side of the filter. With this structure, it is possible to burn the particulates captured by the filter at a relatively low temperature, prolonging the life of the casing, and reducing the amount of expensive catalyst supported on the filter. Furthermore, since the rise in temperature caused by the catalytic reaction is minimized, it is possible to prevent the filter from being damaged by high heat.

[Brief explanation of the drawing]

The figure is a sectional view of the filter of the present invention. DESCRIPTION OF SYMBOLS 1... Exhaust particulate separator, 2... Casing, 3... Filter, 4... Heating device, 5... Catalyst supporting part, 6... Catalyst not supporting part.

Claims (1)

[Scope of utility model registration request] A casing is provided in the middle of the exhaust pipe, and a filter is provided in the casing in which a heat-resistant catalyst-carrying part carrying a catalyst and a non-catalyst-carrying part are arranged alternately, and a filter is provided on the upstream side of the filter. Exhaust particulate separation equipment equipped with a heating device.