KR970001457B1 - Particulate substance reduction system of a diesel car - Google Patents

Abstract

The system is designed to regenerate a filter using a burner and thereby reduce particulate matters during the exhaust gas of a diesel engine. The system includes a trap part including a burner part having a nozzle and a firing means, a mixing liner, and a ceramic filter; a branched pipe dividing the exhaust gas of the diesel engine into the trap part and a noise generator; a first air supply part for supplying air to the burner part with an air fan and an on/off valve; a second air supply part including an air pump, an air regulator connected to the air pump, and a three-way valve having a first port connected to the air regulator, a second port connected between the branched pipe and the trap part, and a third port connected to a pipe for supplying fuel from a fuel tank to the nozzle; and a third air supply part including a butterfly valve driven by a motor.

Description

Particulate matter reduction system of diesel vehicle

1 is a block diagram showing the configuration of a particulate matter reduction system of a diesel vehicle according to an embodiment of the present invention.

3 is a block diagram of a particulate matter reduction system of a conventional diesel vehicle.

[Industrial use]

The present invention relates to a system for reducing particulate matter in exhaust gas of a diesel engine, and more particularly, to a system for regenerating a filter using a burner.

In diesel vehicles, total partoculate matter is a generic term for soot and unburned hydrocarbon, and it is known that it is harmful to the human body. It is a technique of filtering a substance and forcibly burning the filtered particulate matter periodically or at any time. That is, the regeneration of the filter to a clean state before filtration by burning particulate matter filtered through the filter is the most essential part of the regeneration technology. The combustion method can be roughly divided into self-combustion and forced combustion methods, and the forced combustion method includes an electric heater and a burner system method. The present invention relates to a burner system.

The burner system has the advantages of easy control of the ignition temperature, accurate ignition at a desired time point, very easy supply of energy source, and no effect on the operation of the engine.

[Private Technology]

As a conventional burner system, A.D. Tuteja et al., Published in the SAE paper 920142 in 1992, is shown in FIG.

In this model, the exhaust gas of the diesel engine 100 passes through the orifice valve 102 via the branch pipe 101. The exhaust gas passing through the orifice valve 102 passes through the nozzle unit 103 and passes through the mixing liner 104 to filter particulate matter from the filter 105.

The orifice valve 102 opens and closes a valve plate (not shown) by a vacuum actuator (not shown) so that the shear area is opened during filtration and only the orifice is opened during regeneration. The reason why the orifice is open during regeneration is to reuse the exhaust gas for combustion.

The nozzle unit 103 has an ignitor plug 106 in the radial direction, and an air tube 107 and a purge tube 108 for supplying atomization air during regeneration to the nozzle are disposed in front of the nozzle unit 103, respectively. It is. The purge pipe 108 supplies fuel during regeneration by the purge valve 109 and air to prevent contamination of the nozzle during filtration.

That is, the purge valve 109 is connected to the fuel pump 110 and the fuel flows through the fuel tank (not shown) and the fuel heater 111 to the purge valve 109.

The fuel pump 110 has a somewhat complicated structure to control the amount of fuel supplied to the purge pipe 108 to stabilize the combustion according to the combustion pressure during regeneration. For example, the feed to the purge pipe 108 is 0.9 to 3.2 kg / h.

Meanwhile, purge air supplied to the purge valve 108 and atomized air through the air pipe 107 are supplied from the air pump 120 through an air regulator 112 and serve as the air regulator 112. The back pressure applied to the mixing liner unit 104 is transmitted through a feedback port 113 to adjust the amount of atomized air and purge air to serve to stabilize combustion.

On the other hand, the mixing liner unit 104 has a pressure sensor 114 and a temperature sensor 115 to determine the regeneration time, and transmits the measured value to the electronic interface unit 116 and the electronic interface unit 116 Comprehensively controlled by an electronic control module or electronic control unit 117.

Meanwhile, exhaust gas bypassed during regeneration is discharged toward the silencer 118 to which the filter 105 is not connected, and a pressure relief valve 119 is mounted at the outlet of the silencer 118. The pressure relief valve 119 at the time of filtration is blocked by the pintle (not shown) by the camlock linkage (not shown) driven by the vacuum pump 121, and the force acting by the cam lock at the time of regeneration is removed. It is blocking the exit of the silencer 118 by the force of the spring.

Therefore, since the outer solenoid valve 102 only opens the orifice at the time of regeneration, when the pressure of the silencer 118 rises and reaches a certain pressure, the pressure of the spring of the pressure relief valve 119 is overcome and the exhaust gas is discharged.

In FIG. 3, reference numerals S1, S2, and S3 denote solenoid valves for controlling the connected parts, and each line connected to the diesel engine 100 in the electronic controller 117 shows connection with various sensors.

However, as described above with reference to FIG. 3, the particulate trap device by Tuteza et al. Is too complicated to be applied to a real vehicle in terms of technology and cost, and also causes problems of durability as the entire structure and each component are complicated. do. At the time when a device with high durability and stability has not been developed to date, it is almost impossible to apply the model to a real vehicle since the best goal of the trap technology of diesel engine is to apply to a real vehicle.

In addition, the fuel consumption during regeneration is not only high, but also the exhaust gas passes through the nozzle unit 103, the spark plug 104, the air pipe 107, the purge pipe 108, etc. above all, these are disposed at the top Due to the mechanisms, exhaust gas and atomized air tend not to be evenly fed to the filter, but tend to be driven downward.

In the trap technology of diesel engines, the most important technical problem is that the filter is stable against thermal shock during regeneration. Therefore, the model may have a problem of combustion stability due to unevenly supplied air.

[Object of the present invention]

The present invention has been made to overcome the problems of the prior art as described above. The first object of the present invention is to provide a particulate matter reduction system that can be applied to an actual diesel engine by simplifying the configuration to satisfy durability and cost. .

It is a second object of the present invention to provide a particulate matter reduction system capable of minimizing fuel consumption during regeneration of a filter.

It is a third object of the present invention to provide a particulate matter reduction system in which the combustion is stabilized upon regeneration of the filter so that the filter is stable due to thermal shock. Other objects and advantages of the present invention will be understood from the accompanying drawings and the detailed description.

[Way]

In order to achieve the above objects, the present invention provides a burner unit having a nozzle and an ignition means, a trap unit including a ceramic filter, a silencer, and a branch pipe separating the exhaust gas of a diesel engine into the trap unit and the silencer. And a first air supply unit for supplying air to the burner unit including a blower and an on / off valve, an air regulator connected to an air pump and the air pump, and a first port connected to the air regulator and a second port connected to the air regulator. A second air supply portion connected between the branch pipe and the trap portion, the third port including a three-way valve connected to a pipe for supplying fuel from the fuel tank to the nozzle, and a butterfly valve driven and regulated by a motor; It provides a particulate matter reduction system of a diesel vehicle comprising a third air supply.

Example

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a view showing the overall configuration of a particulate matter reduction system of a diesel vehicle according to an embodiment of the present invention. The exhaust gas of the diesel engine 1 is divided into a particulate matter reducing device 50 (hereinafter referred to as a trap) and a silencer 4 by a branch pipe 2, and a first on / off valve is provided at the inlet of the trap 50. There is (5). The air pressurized and supplied from the air pump 6 driven by the diesel engine 1 is transferred to the first port 9 of the three-way valve 8 via the air regulator 7 and the three-way valve 8 The second port (9 ') of the) is connected between the first on, off valve (5) and the trap (10).

The trap unit 10 includes a nozzle 11, an ignition transformer 12, an ignition rod 13, and a ceramic filter 3, and is supplied from a fuel tank (not shown) to perform a heater role. A fuel 15 passing through 14 passes at a predetermined point and communicates with the nozzle 11 in communication with the third port 9 ′ of the three-way valve 8.

Meanwhile, air introduced through the blower 16 having an air filter (not shown) is supplied to the nozzle 11 through the second on / off valve 17 and the ignition transformer 12 and the ignition rod 13 are It is located in the front part of the jozel 11. An air supply unit including the blower 16 and the second on / off valve 17 is defined as a first air supply unit, and the air supplied from the air supply unit is called a primary air supply.

An air supply unit including the three-way valve is defined as a second air supply unit, and the air supplied therein is called a second secondary air.

The exhaust gas passing through the nozzle 11 and the ignition rod 13 passes through the mixing liner 18 and the exhaust gas passing through the mixing liner 18 is filtered by the ceramic filter 3.

One of the branch pipes 2 is connected to the silencer 4, and exhaust gas is delivered to the silencer 4 during regeneration, and at the inlet, there is a butterfly valve 27 and a motor 26 driving the branch pipe 2. The butterfly valve 26 and the drive motor 27 are defined as the third air supply, and the air supplied to the trap 50 is referred to as the third air.

Meanwhile, the temperature sensor 19 and the pressure sensor 20 are disposed between the ceramic filter 3 and the mixing liner 18 so that the sensed information is transferred to the electronic interface unit 21. The electronic interface unit 21 transmits information to an electronic control unit 22, and the electronic control unit 22 is a throttle opening degree sensor 23 and an engine speed sensor 24 connected to the diesel engine 1. ), And determine and control the information in combination with information such as the atmospheric pressure sensor (25).

The electronic controller 22 is also connected to a valve control motor 26 which drives the butterfly valve 27 at the inlet of the silencer 4 and the valve control motor 26 also controls the electronic interface unit 21. Are connected.

The electronic controller 22 is a second solenoid valve S1 for driving the first on / off valve 5 and a second on / off valve connected to the vacuum pump 30 driven by the diesel engine 1. A second solenoid valve S2 for driving 17 and a third solenoid valve S3 for driving the three-way valve 8 are also connected.

FIG. 2 is a view showing the mixing liner 18 side of the trap 50 in FIG. 1 from the mixing liner 18 side to the nozzle 11 side. ), Three holes 31, 31 ', and 31 are provided.

That is, by evenly arranging the inlet through which the exhaust gas enters, the exhaust gas is evenly distributed in the mixing liner 18 and the filter 3 to stabilize the combustion during regeneration, thereby reducing the thermal shock applied to the filter 3.

Referring to the operation of the particulate matter reduction system of the diesel engine according to an embodiment of the present invention configured as described above are as follows. The operating mode of this system can be divided into filtering mode and regeneration mode.

(1) Filtration mode

During this mode of operation exhaust gas from engine 1 enters trap 50 and does not enter silencer 4. At this time, the particulate matter in the exhaust gas entering the trap 50 is filtered by the ceramic filter 3 constituting the trap 50 (at this time, about 90% or more of the particulate matter is filtered out). Clean air is released into the atmosphere.

That is, during this process, the butterfly valve 27 installed just before the silencer 4 is closed and the first on / off valve 5 installed at the inlet of the trap 50 is open. Since the nozzle 11 for injecting fuel is not injecting fuel at this time, the nozzle 11 may be exposed to the exhaust gas and be contaminated. In order to prevent such nozzle contamination, the air pressurized at low pressure by the air pump 6 installed in the engine passes through the air regulator 7 and is supplied to the nozzle 11 through the three-way valve 8. . Therefore, in the filtration mode, the nozzle 11 injects only air.

At this time, the blower 16 is not driven and the second on / off valve 17 between the blower 16 and the trap 50 is closed so that there is no leakage of exhaust gas. If particulate matter contained in exhaust gas is continuously filtered in this way, the filter 3 is clogged by such particulate matter, and thus the back pressure of the engine is increased to reduce the exhaust efficiency and increase fuel consumption to produce the same output. . In addition, if the engine is left in such a state continuously, the engine will not exhaust the combustion gas and the engine will be turned off.

Therefore, in order to continuously filter the particulate matter in the ceramic filter 3, a process of regenerating the filter 3 after proper filtration should be performed. The regeneration of the filter 3 refers to a process of supplying a gas of high temperature (500-600 ° C.) to the particulate matter deposited on the filter 3 to reburn it. When the particulate matter deposited on the filter 3 is re-burned, it is burned in the form of almost carbon dioxide and exits the filter 3, and the filter can be used again to filter the exhaust gas from the engine.

(2) regeneration mode

When the filtration mode is advanced and the pressure in the trap 50 reaches an appropriate value, regeneration is started. That is, it becomes a target value for determining the start of reproduction at this time. When the pressure value in the trap 50 from the pressure sensor 20 reaches the target value, this signal is input to the electronic control unit 22 via the electronic interface unit 21 and the electronic control unit 22 is previously input. The playback will begin by comparing the set value. Here, the electronic controller 22 receives all sensor signal values of the system, determines the signal values, and sends out a signal for controlling the system to the electronic interface unit 21. In other words, it is the brain of the controller of the system.

When the regeneration is started, the compressed air supplied from the air pump to the nozzle 11 by the signal of the electronic controller 22 is switched to the second port 9 'by the three-way valve 8, and the trap ( 50) It is supplied to the previous exhaust pipe. At this time, the fuel pressurized from the fuel pump 14 is supplied to the nozzle 11 at about 0.7 kg / h, and the high-frequency ignition is performed by the ignition rod 13 installed at an appropriate position in front of the nozzle 11. The high frequency current is supplied from the ignition transformer 12 connected to the telephone bar 13. Of course, the opening and closing of the power supplied to the ignition transformer 12 is the electronic interface unit 21 is opened and closed by the signal of the electronic control device 22.

If the fuel injected from the nozzle 11 succeeds in ignition, the temperature signal rising from the temperature sensor 19 located in front of the filter 3 is sent to the electronic controller 22 through the electronic interface unit 21 and ignited. It will be determined that has been made.

In the early stages of ignition the flame stability is very sensitive to the amount of air supplied. In order to actively control these sensitive changes, air for atomization of fuel injected from the nozzle 11 and fuel-air mixing is supplied from the blower 16 and the air flow rate of the blower 16 is controlled by the electronic controller 22. It is very delicately controlled by the control. In this sense, therefore, the air from the blower 16 is called primary combustion air. However, since the amount of air controlled by the blower 16 alone cannot guarantee complete combustion of fuel in a very short time, more secondary air must be supplied from the air pump 6 which is driven with the engine and completely burned. .

If the fine control of the first and second air fails, the secondary pollutant discharge by the burner 10 constituting the trap 50 becomes serious. In addition, the temperature gradient inside the ceramic filter 3 which directly forms the trap 50 to filter the engine exhaust gas cannot be finely controlled, so that the ceramic filter 3 is cracked. If a crack occurs in the ceramic filter 3, the exhaust gas is not filtered between the cracks and is exhausted into the atmosphere, so that the function of the system is not normally exhibited.

This phenomenon is called thermal shock and requires very fine control of the primary, secondary and tertiary air flow rates to prevent thermal shock. In particular, the butterfly valve 27 located in front of the silencer 4 is driven by the motor 26, and the drive motor 26 controls the opening degree of the butterfly valve 27 very delicately, so that a part of the exhaust gas is trapped. 50) can be used as tertiary combustion air during regeneration to control the temperature gradient inside the filter.

[effect]

As described above, the particulate matter reduction apparatus of the diesel vehicle according to the present invention is able to satisfy the durability and cost by presenting a model that is much simpler than the conventional apparatus for applying to a real vehicle, and it is about 0.9 to 3.2 kg Only 0.7kg / h could be supplied compared to a device that used a lot of fuel / h, which is advantageous in terms of fuel economy, and it was possible to protect the filter from thermal shock by equalizing the passage of the exhaust gas by canning the mixing liner.

Although the particulate matter reduction apparatus of the diesel vehicle according to the present invention is shown only one embodiment, it will be understood by those skilled in the art that various modifications are possible according to the spirit of the present invention. I will understand that it is not beyond.

Claims (2)

A burner section having a nozzle and a ignition means, a trap section including a mixing liner and a ceramic filter, a silencer, a branch pipe separating the exhaust gas of a diesel engine into the trap section and the silencer, a blower, A first air supply unit for supplying air to the burner unit including an off valve, an air regulator connected to the air pump and the air pump, a first port connected to the air regulator, and a second port connected to the branch pipe and the trap unit And a third air supply part including a third air supply part including a three-way valve connected to a pipe for supplying fuel from the fuel tank to the nozzle, and a third air supply part including a butterfly valve driven and regulated by a motor. Particulate matter reduction system of diesel vehicle including. The particulate matter reduction system of claim 1, wherein the mixing liner inlet is canned to allow passage of diesel exhaust gas through three or more holes.