JPS61164023A - Exhaust gas purifying device of engine - Google Patents

Abstract

PURPOSE:To suppress the temperature rise of a filter, by providing an injection device, which injects combustion promoting fluid of a combustible particle, in the upstream of the particulates filter provided in an exhaust system and blocking a fine holed part not penetrating through a cell wall of said filter by a blockade material. CONSTITUTION:An exhaust gas purifying device, providing in the half way of an exhaust passage 2 a particulates filter 4 for catching a combustible particle in exhaust gas, provides an injection device 6, injecting fluid promoting combustion of the combustible particle, in the exhaust passage 2 in the upstream side of said filter 4. This injection device 6, being constituted by a tank 7, injector 8 and a pump 10 or the like, is controlled by a control circuit 11. Said filter 4 has a cell wall 5 forming many fine holed parts, and the fine holed part has penetrative fine holed parts 13... through the cell wall 5 while non- penetrative fine holed parts 14... not through the cell wall 5, but here the non- penetrative fine holed part 14..., being blocked by a blockade material 15 consisting of ceramic material, forms a surface almost equal to the surface of the cell wall.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust gas purification device that purifies engine exhaust gas, and in particular, the present invention relates to an exhaust gas purification device that purifies engine exhaust gas. It is related to a device that collects and burns off particulates.

(Prior Art) Various exhaust gas purification devices of this type have been proposed in the past. As an example, for example, JP-A-56-9°8
As disclosed in Japanese Patent No. 519, a catalytic filter is disposed in the exhaust system of the engine to collect combustible particles in the exhaust gas and cause an oxidation reaction, and upstream of the catalytic filter, a catalytic filter is installed to combust the combustible particles. For example, an injection device is provided that injects liquid fuel as the liquid that promotes the combustion, and the exhaust gas temperature is heated to the ignition temperature of the combustible particles or higher by the oxidation reaction effect of the catalyst in the catalyst filter and the combustion promotion effect of the liquid fuel. It is known that the filter is regenerated by burning and removing combustible particles collected on the catalyst filter.

(Problems to be Solved by the Invention) In addition, the present applicant previously proposed in Japanese Patent Application No. 59-64627 that a conventional engine exhaust system having only the function of collecting combustible particles, instead of a catalytic filter, is installed in the engine exhaust system. A particulate filter is provided, and a liquid that is a mixed emulsion of a catalyst component and a hydrocarbon component is injected and supplied to the exhaust passage upstream of the particulate filter as a liquid that promotes combustion of combustible particles. By doing so, the catalyst and hydrocarbon components are evenly deposited on the surface of the combustible particles collected in the particulate filter, significantly lowering the ignition temperature of the combustible particles, resulting in a low exhaust gas temperature. We are proposing a technology that reliably burns and removes combustible particles even during steady engine operation. This particulate filter has a large number of pores formed through its cell walls, and these through pores collect combustible particles, which are then combusted by the liquid. By removing it, communication between the through pores is maintained and an increase in engine back pressure is prevented.

However, since the cell walls of such particulate filters have many pores that do not penetrate, the liquid may adhere to these pores and waste the amount of liquid supplied. There is a problem of increasing Also, in this case,
Since combustible particles may be trapped in the impermeable pores, there is a risk that the temperature of the particulate filter will rise significantly due to the combustion reaction between these flammable particles and the liquid, causing cracks to occur. .

(Object of the Invention) The present invention has been made in view of the above points, and its purpose is to eliminate portions of the cell wall of the particulate filter that do not contribute to suppressing the increase in back pressure (i.e., non-penetrating pores). In addition to reducing the supply amount of the liquid by preventing it from being deposited on the liquid that promotes the combustion of combustible particles,
The purpose is to suppress the rise in temperature of the particulate filter by preventing combustible particles from burning in the part.

(Means for solving the problem) In order to achieve the above object, the solution of the present invention provides an engine exhaust gas purification device equipped with a particulate filter that collects combustible particles in the exhaust system. target,
On the other hand, an injector is disposed upstream of the particulate filter to inject and supply a liquid that promotes combustion of the combustible particles.

Furthermore, the particulate filter has a structure in which the pores that do not penetrate through the cell walls are plugged with a plugging material.

(Function) According to the above configuration, the pores of the particulate filter that do not penetrate the cell wall of the present invention are blocked with a blocking material, so that combustible particles can be collected and ejected from the injector. The liquid does not adhere to these non-penetrating pores, but only to the pores that penetrate the cell wall, which reduces the amount of injected liquid supplied and reduces the particulate filter's performance. The combustion reaction between the combustible particles and the injected liquid in the non-penetrating pores is also prevented.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall configuration of an embodiment of the present invention, in which 1 is a swirl chamber diesel engine, 2 is a combustion chamber 3 of the engine 1, and 2 is a combustion chamber 3 of the engine 1.
A particulate filter 4 is disposed in the middle of the exhaust passage 2 to collect combustible particles mainly composed of carbon in the exhaust gas. There is. The particulate filter 4 is formed by alternately closing the openings at both ends of a large number of honeycomb holes in a honeycomb body made of a porous material, and closing the cell walls 5, 5, . . . between adjacent honeycomb holes. It filters exhaust gas as it passes through and collects combustible particles.

Reference numeral 6 denotes an injector for injecting and supplying a liquid for promoting combustion of the combustible particles to the exhaust passage 2 upstream of the particulate filter 4, and the injector 6 stores the liquid for promoting combustion. A tank 7 , an injector 8 disposed in the exhaust passage 2 upstream of the particulate filter 4 with a spout 8 a facing the surface of the filter 4 and having an electromagnetic on-off valve 8 b , and a communication pipe connecting the injector 8 to the tank 7 . 9, and an electric liquid supply pump 10 disposed in the middle of the communication pipe 9, the liquid supply pump 10
and opening of the electromagnetic on-off valve 8b of the injector 8, the liquid in the tank 7 is pumped to a predetermined amount (for example, 10 to 100
cc) It is made to inject toward the filter 4 from the spout 8a of the injector 8, and to make it adhere to the surface. The liquid that promotes the combustion of the combustible particles is, for example, a water-soluble compound of 0.05 to 0.5 weight 11% of - or two or more platinum metals (Pt, Pd, Rh, Ir),
Or 1 to 10% by weight of - or di-superior base metals (
V, Cu, Cr, Fe, Ni, Mo.

a catalyst component consisting of a water-soluble salt of Ca, f3a);
10 to 50% by weight of a hydrocarbon such as kerosene, light oil, heavy oil, alcohol, ketone (oxygenated hydrocarbon), 1 to 10% by weight of a surfactant for dissolving the hydrocarbon in water, and the remainder water. It consists of these ingredients and is made into an emulsion by mixing them.

Further, 11 is a control circuit for controlling the operation of the electromagnetic on-off valve 8b of the injector 8 and the liquid supply pump 10 in the injector 6, and the control circuit 11 receives an engine rotation speed signal, an engine load signal, An output signal from a back pressure sensor 12 that is disposed in the exhaust passage 2 immediately upstream of the particulate filter 4 and detects the exhaust gas pressure, that is, the back pressure of the engine 1 is input, and the output signal is input to the back pressure sensor 12 to detect the operating range of the engine 1. , searches for the preset and stored appropriate back pressure when the filter 4 is not clogged in that operating range, and compares and compares the actual back pressure detected by the back pressure sensor 12 with the appropriate back pressure. It is determined whether or not the filter 4 is clogged, and if the actual back pressure is higher than the appropriate back pressure and the filter 4 is clogged, the liquid supply pump 10 of the injector 6 and the electromagnetic on-off valve 8b of the injector 8 are activated. The injector 8 is configured to output an activation signal to cause the injector 8 to inject liquid.

As shown in FIG. 2, a large number of pores are formed in the cell wall 5 of the particulate filter 4. The pore portion has a through pore portion 13.1 that penetrates the cell wall 5.
3... and non-penetrating pores 14.1 that do not penetrate the cell wall 5
4... and the non-penetrating pore portion 14 is closed with a closing material 15 made of a ceramic material to form a cell g! It is formed almost flush with the surface of 5.

Next, to explain the method of blocking the impenetrable pores 14 with the blocking material 15, first, alumina hydroxide and its 10
Mix it with twice the weight of water to prepare a slurry liquid. Then, the particulate filter 4 is immersed in this slurry liquid from one side so that the cell walls 5, 5... are perpendicular to the liquid surface to impregnate the pores 14.15 with the slurry liquid. Pull up and open the through hole part 13 by air bubble O-.
13. Remove the slurry liquid impregnated with... after that,
After drying at 150°C for 1 hour, further drying at 500°C.
By firing for 3 hours, the through pores 13.
. . communicate with each other and the non-penetrating pore portions 14, 14 . . . are closed with a ceramic material (alumina).

Next, to explain the operation of the above embodiment, exhaust gas discharged from the combustion chamber 3 of the engine 1 is filtered by the cell walls 5.5 of the particulate filter 4. Although combustible particles are collected in the pores of Hole 1
3.13... will be collected only. Furthermore, when the particulate filter 4 is clogged, the injector 8 injects a liquid that promotes the combustion of combustible particles, but this liquid is also used exclusively in the through-hole portions 13, 13, and 13, like the combustible particles. It will only adhere to... Therefore, the injected liquid adheres only to the through-hole portions 13, 13, where the combustible particles are reliably collected, so that the injected liquid is not wasted and is provided for combustion reaction with the combustible particles. The reason for its supply can be reduced as much as possible, and the running cost of the engine 1 can be reduced.

Moreover, since the -cut flammable particles and the injection liquid do not enter the non-penetrating pores 14, 14..., the combustion reaction between the combustible particles and the injection liquid takes place only in the through-pores 13. Therefore, it is possible to suppress the temperature rise of the particulate filter 4 as much as possible, prevent the occurrence of cracks, etc., and improve its heat resistance strength.

Furthermore, since the non-penetrating pores 14, 14... have no function of communicating with the cell walls 5, even if the non-penetrating pores 14, 14... are closed, the increase in back pressure cannot be suppressed. This is done by a combustion reaction in the through-hole portions 13, 13, etc., as in the past, and no adverse effects occur.

Figure 3 shows an exhaust gas purification device equipped with a particulate filter (an example of the present invention) in which the impermeable pores are closed with a clogging material (r11) and a particulate filter in which no treatment is applied to the impermeable pores. Regarding the exhaust gas purification device (conventional example), the amount of injected liquid inside the particulate filter was measured when the same amount of liquid was injected once from the injector, and the results of an lc experiment are shown. From the same figure, in the conventional example shown by the broken line, it is approximately 10C from the inlet of the particulate filter.
Almost all of the liquid is deposited up to point 11, whereas in the example of the present invention shown by the solid line, it is deposited up to about 20 CI from the inlet, and a large amount of the ejected liquid is deposited due to the blockage of the non-penetrating pores. This shows that the coating can be applied uniformly to the through-pores. This shows that combustible particles can be burned efficiently even with a small amount of injection liquid. In addition, in this case, the ignition temperature is 210 degrees, which is sufficiently low in the example of the present invention compared to 232 degrees in the conventional example, and the proportion of burned particles among the collected combustible particles is 67.8% in the conventional example. The invention example has a high rate of 83.6%, indicating that the injection liquid has sufficiently reduced the ignition temperature and promoted the combustion of combustible particles.

4 and 5 respectively show modified examples of the particulate filter, and FIG. 4 shows the particulate filter 4 when the injection pressure of the injector 8 is set high.
'The flow rate of the injected fuel is several times faster than the gas flow rate in the particulate filter 4', so the injected liquid is hardly affected by this gas flow. The front surface of the filter 4' is formed in a concave shape so as to be equidistant from the spout 8a of the injector 8, so that the sprayed liquid can be uniformly deposited on the front surface of the filter 4'. Furthermore, Fig. 5 shows the shape of the particulate filter 4'' when the injection pressure of the injector is set low. Since the flow rate of the injected fuel is several times slower than the gas flow rate in the particulate filter 4'', the injection Focusing on the fact that liquid is affected by gas flow,
Injector 8 in front of particulate filter 4''
It is formed in a convex shape toward the jet nozzle 8a of the particulate filter 4'', which makes it possible to uniformly distribute the gas flow velocity in the radial direction of the particulate filter 4'' and to uniformly deposit the injected fuel on the front surface of the filter 4''. becomes.

Also in these cases, the particulate filters 4L, 4
The pores that do not penetrate through the cell walls of // are closed with a closing material, and the same effects as in the above embodiment can be achieved.

Incidentally, when the catalyst component in the liquid is magnetizable, a magnetic field may be created between the injector 8 and the filters 4.4', 4'' to guide the liquid jet flow, and the same effect as in the above modification example can be obtained. It can be effective.

Furthermore, in this example, a liquid mixture containing a catalyst component and a hydrocarbon component was used as the liquid that promotes the combustion of combustible particles. A liquid containing only one of the two may also be used.

(Effects of the Invention) As explained above, according to the engine exhaust gas purification device of the present invention, the pores that do not penetrate the cell walls of the particulate filter are blocked with the plugging material, and the pores that do not penetrate the cell walls of the particulate filter are blocked. Since combustible particles are collected only in the pores and are coated with the injected liquid from the injector installed upstream of the particulate filter, the amount of injected liquid supplied can be reduced and running costs can be reduced. In addition, it is possible to suppress the combustion reaction between the combustible particles and the injected liquid in the particulate filter, thereby suppressing the temperature rise of the filter and improving its heat resistance strength.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall schematic configuration diagram, FIG. 2 is an enlarged cross-sectional view of main parts, FIG. 3 is an experimental result diagram showing the distribution of the injected liquid, and FIGS. 4 and 5. 2A and 2B are cross-sectional views showing modified examples of particulate filters, respectively. 1...Engine, 2...Exhaust passage, 4.4', 4"
...Particulate filter, 5...Cell wall, 6
... Injector, 13... Penetrating pore part, 14... Impermeable pore part, 15... Clogger.

Claims (1)

[Claims] (1) In an exhaust gas purification device for an engine equipped with a particulate filter that collects combustible particles in the exhaust system, an injection supplying a liquid that promotes combustion of the combustible particles upstream of the particulate filter. What is claimed is: 1. An exhaust gas purification device for an engine, characterized in that the particulate filter has a particulate filter whose pores that do not penetrate through the cell wall are plugged with a plugging material.