JPS58104313A - Purifying device of diesel engine exhaust particle - Google Patents

Abstract

PURPOSE:To improve inflammability of exhaust particles with a simple configuration in a device equipped with an exhaust particles collecting material in a course of exhaust gas by providing an exhaust throttle valve in an exhaust gas course and also providing an electric heater on the upper stream side of the collecting material. CONSTITUTION:A trapper container 10 filled up with exhaust particles collecting material (trap material) 11 is provided in an exhaust duct part on the downstream side of an exhaust manifold 4 of a diesel engine. Further, an exhaust throttle valve 20 is also provided in the downstream of the trapper container 10, and a valve 21 is driven by means of a negative pressure selector valve 22 through a diaphragm valve 21 and a link or the like. The negative pressure selector valve 22 controls an exhaust throttle valve 20 in the direction of throttling when the trap material 11 is decided by CPU30 to be in the time of regeneration. Further, an electric heater 12 is provided on the end of the upper stream side of the trap material 11 in the trapper container 10. Said heater is set conductive to help firing and combustion of the exhaust particles when the exhaust throttle valve 20 is throttled and the temperature of the exhaust grows above the predetermined level.

Description

[Detailed description of the invention]

This article relates to exhaust gas treatment equipment for diesel engines, and more specifically, carbon particles contained in exhaust gas and F1-like particulates (hereinafter referred to as exhaust particles)
Exhaust particulate purification V&I is suitable for collecting exhaust particulates by physical methods, periodically incinerating the collected exhaust particulates, and regenerating them with a collection material. Most of the cancer particles are easily decomposable (Q), and in order to collect these highly-capable particles, incinerate the collected particles, and regenerate the collection material, it is necessary to Conventionally, the following methods have been known. (1) Throttle the intake system of the diesel engine 43. The amount of intake air is reduced to increase the temperature of exhaust gas, reducing exhaust particulates by 1
How to bake. (2) An oil burner is installed in the exhaust system of the f' easel engine, and the temperature of the exhaust gas is adjusted to the temperature at which the exhaust particulates are twisted.
Method of incinerating by raising the exhaust particles at t (3) Attach an electric heater to the entire surface of the collection material, and burn the attached exhaust particulates on the surface C of the collection material.
L,! A method of using downstream particulates as a heat source @ Umada Recently, this application has been filed in which the method (1) and method (3) 1 are combined to make the exhaust particulate V twist part and regenerate the collection material. (Japanese Patent Application No. 1983-96614, proposed by the same applicant as 1). However, even if the intake system throttle is used to raise the exhaust temperature and improve the ignitability of the exhaust particles that reach the electric heater,
Under the operating conditions of the engine (for example, when the operating condition of the engine changes during regeneration), t = The purpose is to eliminate the above-mentioned disadvantages, improve durability,
It is an object of the present invention to provide an exhaust particulate purification device for a diesel engine that has an excellent safety, simple structure, low cost, and good ignitability of exhaust particulates. In an exhaust particulate purification device for a diesel engine having an exhaust particulate collection material V in the exhaust pipe, a throttle valve is provided in the exhaust pipe which is not normally throttled, and a throttle valve is provided on the upstream end face of the collection material. 1 supplied to the electric heater and/or engine
It is characterized by having means for increasing the amount of fuel injection. V
The fuel increase means, the exhaust throttle valve and the electric heater are operated in conjunction periodically during engine operation. Such a throttle valve can be installed upstream of the collection material.
Also, even if it is installed downstream, Lln6 and this aperture 5? It is also possible to provide the exhaust manifold with a mouth restrictor 9Pv.
However, as the back pressure of the exhaust gas increases, the temperature of the exhaust gas rises to the temperature required for burning the exhaust particles.・The exhaust flow velocity inside the trap or on the upstream surface thereof is still small. This makes it easier for the electric heater to ignite exhaust particulates. In other words, it is possible to reduce the cooling loss. When the exhaust throttle valve is throttled, the amount of fuel injected to the carrot is increased, so the output stability of the diesel engine - mA will not be affected.Means for increasing the amount of injection and exhaust The throttle valve is controlled by a combinator or the like so as to operate periodically in conjunction with the operation of the engine. The electric heater is preferably a plurality of (ceramic) electric heater elements arranged in a distributed manner, with each heater element connected to v11! It is better to reduce power consumption as much as possible by taking special measures to reduce the heating temperature. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Beast 1 Figure 5: %1 is the diesel engine body, 2 is the transmission cylinder, 3 is the intake manifold, 4 is the exhaust manifold%5 is the fuel injection pump, 6 is the fuel pipe, 7 is 1
Fuel injection valve (injector), 8 is a vacuum pump, 9
is a cooling fan, and a trapper container 10 is attached to the exhaust pipe line below the exhaust manifold 40, which is the *a part of a normal diesel engine. Inside the trapper vessel 10, there is a collection material (trap material) 1, as shown in FIG. , soQ) Exhaust gas can flow inside, and r contained in the exhaust gas is
It is designed to be able to collect a considerable amount of wrinkled exhaust particulates. Also. The trapping material 11 periodically burns and ashes the exhaust particulates collected by the trapping material 11 when the engine is operating.
A suitable material with a suitable shape I is required to sufficiently withstand the elevated temperature V to be reached; an example of a material suitable for this purpose is a three-dimensional mesh foam. Ceramic, monolithic ceramic, metal wire
Are the exhaust particulates collected on the Udralap material 11 that has a large amount of screen elements such as mesh or stainless steel? −
In order to burn and ash, it is usually necessary to raise the exhaust temperature to a level of about 560°C. Therefore, the material constituting the trap material must be sufficiently resistant to this temperature; ), the temperature inside the exhaust system changes dramatically under different conditions of engine load and speed, and depending on the position of the particulate trapper in the exhaust system, the temperature inside the trapper changes within the range (= Burn off the collected particulates (never reach the level above 200g, which is typical in many motor vehicle applications, but the engine is rarely under full throttle). If the unit does not operate,
When equipped with a turbocharger, this is especially true if a specific trapper in the power distribution shown in FIG. 111 is cast in the exhaust line downstream of the carrot exhaust manifold. Therefore, in order to periodically incinerate the collected particulates, it is necessary to provide some other means for raising the exhaust temperature to the required level of approximately 560°C. A number of possibilities can be used singly or in combination to obtain engine exhaust gas. Appropriate throttling of the exhaust can substantially increase the engine exhaust by 1ft', and in some cases can increase the temperature in the particle trapper by as much as 11 ft of light to the level of ashing. In other words, in the present invention, an exhaust throttle valve 20 is provided at an appropriate position on the lower cap of the trapper vessel 10 of the exhaust pipe line in which the current flow is not restricted. The diaphragm valve 21 is connected to a diaphragm valve 21, and the diaphragm valve 21 is driven by a negative pressure switching valve (VSV) 22.
2 is Baki$-A! ! lr', connected to the Vaquième pump 8 via the tube 23, while connected to the micro combinator (CPU) 301 via the wiring 24g. Flam valve 2I (: is a microcomputer (C) that opens the exhaust throttle %20 due to the action of the atmosphere
When a signal is transmitted from the PU) 30 through the wiring 2411, the atmospheric port of the VSV 22 is closed, and the negative pressure from the vacuum pump 8 or the vacuum piping 23 and the VSV 22 are
acts on the diaphragm valve 21 through the diaphragm valve 21, which closes the L throttle valve 20, and approximately 9 (1%
It is also possible to provide the exhaust throttle I) on the downstream side of the trapper container 10, but in the present invention, the regular injection t'lk: means for increasing the amount of fuel that is supplied to the engine is the provision. That is, %# A-fuel injection pump 5-fuel increase @
33'lJf Controlled negative pressure switching valve (VSV) 3
1 is provided, and this VSV 31 is connected to the microcomputer (CPU) so through the wiring 32g and is also connected to the vacuum pump 8 through the piping 34. Therefore, the microcomputer (CPU) 30
When the signal is transmitted from 32f to VSV
31 transmits negative pressure to the fuel injection amount increase@@@33 through the piping 34, and this fuel injection II pupil 33 increases the fuel injection amount.Furthermore, in the present invention, the ignition of exhaust particulates is , an electric heater flI112 is provided at the upper R11411 end of the collecting material C trapper) 11 as a means for assisting the twisting part. Or the ceramic heater element 13 will fail. Each heater element 13 does not receive IR from a coil-shaped winding like a normal electric heater, but has an XfL as shown in FIG.
To attach the heater elements 13 formed in a zigzag shape, a plurality of heater elements 13 are distributively attached to the honeycomb filter 14. It is sandwiched and fixed between the ceramic filter 14 and the trap material 11. In addition, 15 is a terminal for supplying current to each heater element, and 18 is a ground wire.The size, number, and arrangement of each heater element 13 (31st) are determined to fit the exhaust gas, and to ensure that the These 9J heater elements are energized one by one in sequence.Terminal 15 for current supply
is a voltage converter 16111), the above-mentioned exhaust throttle t+g2g-fuel injection lid increase means 1 connected to the micro combinator (CPU) 30 via the arrangement t7, and the electric heater device 12, During the operation of the engine, they are periodically produced in conjunction with each other to incinerate and ash the exhaust particles and regenerate the trapper 10. is controlled by a microcomputer (CPU) 30. For this purpose, the operating conditions of the engine and the state of exhaust gas are detected and input to the CPU 30. In other words, in Fig. 1, 50 is the engine load. , 51 is the engine rotation speed,
52 is the engine water temperature, 53 is the exhaust pressure before the trapper, 5
4 is the exhaust gas salt before the trapper, 5S is the temperature inside the trapper, and 56 is the exhaust gas salt at the exit of the trapper, and each of these detection signals is input to the CPU 30. Note that 57 is a back pressure sensor that detects the exhaust pressure in front of the trapper. Q) The following points should be kept in mind when designing a control system. The trapper must be cleaned often enough so that the collected particulates do not create too much restriction on the exhaust gas flow. 2. The throttling and sizing of the engine exhaust system must be controlled in such a way that it does not significantly alter the driveability or performance of the vehicle. should not cause a significant increase. 4. - The firing cycle should be controlled so that only the fine particles are burned and incinerated and the bed of the trapper is not damaged. These purposes

[To perform continuous processing 1: In the present invention, the microcomputer (CPU 30) is configured as shown in FIG.
It has been blocked by Turuko. In Fig. 5, first, engine speed f51), engine load (50), trapper bed temperature C55), back pressure (Sho),
Trapper outlet exhaust temperature (56), engine water @ (56)
It is programmed that the next regeneration will be performed after the vehicle has traveled about 70 km after the previous regeneration is completed. This means that the trapper or overload condition is approximately 4
00-, a cleaning interval of about every 70111 is considered appropriate. After it is determined that it is time for regeneration, control is carried out as shown in the flowchart of FIG. 'a5. That is, the exhaust throttle 119P is narrowed and -
The amount of fuel injection is increased to raise the exhaust temperature to the temperature required to incinerate the exhaust particulates. When the exhaust temperature reaches 560°C or higher, the electric heater 12 on the front of the trapper is turned off at 20°C.
Trouble during trapper regeneration (for example, abnormal rise in exhaust gas temperature, etc.) is handled as shown in the flowchart. Inside trapper 1) Floor temperature 66
Regeneration is completed when the trapper inlet exhaust temperature is 560°C or lower and the trapper exhaust temperature is 580°C or lower or continues for 2 minutes, and the micro combinator (CPU)
In the embodiment shown in Figure 5, the decoration time is set to 2 minutes, or it can be set to an appropriate time depending on the accumulation of exhaust particulates and other conditions. Figure 4 shows the state of combustion of exhaust particulates by the heater element 13. Since the heater element 13 is placed on the upper R@end surface of the trap material 11, when it is heated by electricity, it adheres to the vicinity. Exhaust particulate VM burns,
The first burning flame descends along the flow of exhaust gas indicated by arrow P! In Fig. 4, area A is propagated to t1111.
Area B is the area where the exhaust particulates are burned and the trap material is regenerated], and area B is the area where the trap material is not regenerated, but in reality, the electric heater element 13 or more are installed, so the entire area of the trap material 11 is is a recyclable material, the number of electric heater elements 13 and their arrangement are determined to be the minimum number necessary so that exhaust particulates can be completely burned out over the entire area of the trapper material 11. As mentioned in 1 above, power consumption can be reduced by energizing multiple heaters 13v in order, and the exhaust particulates accumulated in the collection material 11 can be reduced by %'! It can be effectively ignited and burned. Note that the present invention can also be applied to a diesel engine equipped with a turbo continuous feeding mechanism. This type of engine has a lower exhaust temperature than a normal engine, but by restricting the exhaust system and increasing the amount of fuel, the twisting part of the exhaust particulates and the 560
You can get the temperature in °C. Spark plugs easily ignite exhaust particulates.

[Brief explanation of the drawing]

Claims (1)

[Claims]! In a diesel engine C having a collection material V for exhaust particulates approximately after the exhaust gas, an exhaust throttle 9Pv is provided in the exhaust gas path which is not normally throttled. Diesel engine exhaust particulate purification** by arranging an electric heater on the upper Rm end face of the collection material. 2. In a diesel engine with a scavenging material for exhaust particulates in the exhaust gas path, an exhaust throttle valve is provided in the exhaust gas path which is not normally throttled. A heater is arranged, and a means for increasing the injection amount supplied to the engine is provided, and the injection amount increasing means, the throttle valve, and the electric power distribution are connected to the engine during engine operation. Exhaust particulate purification device port for a diesel engine provided with a control means that is operated periodically.