JP2011157824A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable exhaust emission control device having a simple structure. <P>SOLUTION: In this exhaust emission control device, a light oil burner 2 having a fuel nozzle 5 and a particulate filter 3 having a filter body 10 collecting diesel particulate are incorporated in the exhaust path 1 of a diesel engine 14 equipped with a common rail type fuel injection device 15. Fuel delivered by a fuel supply pump 21 as the component of the common rail type fuel injection device 15 is introduced to the fuel nozzle 5 of the light oil burner 2 through a pressure reducing valve 28, a fuel forcibly feeding pipe 27 and a metering valve 29. Therefore, air pressure for fuel injection is no more required. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust purification device.

  Diesel engine exhaust mainly contains soot, unburned components of diesel fuel and lubricating oil, components generated from sulfur in the diesel fuel, and other solid matter such as particulate matter (PM). include. Therefore, a particulate filter, which is a PM trapping means, is interposed in the exhaust path of the diesel engine to prevent the PM from being released into the atmosphere, and the collected PM is removed by various methods. Regenerating the curate filter is performed (for example, refer to Patent Document 1).

  FIG. 4 shows an example of a conventional exhaust purification device. A light oil burner 2 and a particulate filter 3 are incorporated in series in an exhaust path 1 of a diesel engine from the upstream side to the downstream side in the flow direction of the exhaust G. It is out.

  The light oil burner 2 includes a cylindrical housing 4 whose one end is used for a mounting seat of an apparatus and the other end is open, and a fuel nozzle 5, a spark plug 6 and an air supply pipe 7 which are attached to one end of the housing 4. Have. The air supply pipe 7 has a role of extracting air from the intake passage (the compressor outlet side of the turbocharger) of the diesel engine and feeding the air into the housing 4. An exhaust pipe 8 for guiding the exhaust G sent from the diesel engine into the housing 4 is connected to one side surface of the housing 4.

  The particulate filter 3 includes a cylindrical housing 9 that is open at both the upstream end and the downstream end in the exhaust gas distribution direction, and a filter body 10 that is housed in the housing 9. The upstream end of the housing 9 in the exhaust G distribution direction is connected to the other end of the housing 4 of the light oil burner 2 described above, and the exhaust pipe 11 connected to the muffler is connected to the downstream end of the housing 9 in the exhaust G distribution direction.

  The filter main body 10 has a porous honeycomb structure made of ceramic, and the inlets (upstream ends in the flow direction of the exhaust gas G) of the flow paths partitioned in a lattice pattern are alternately closed, and the inlets are not closed. The outlet of the flow path (the downstream end in the flow direction of the exhaust G) is closed. In other words, the inlet-side flow path whose upstream end in the exhaust G circulation direction is open and the downstream end is closed, and the outlet-side flow path whose downstream end in the exhaust G flow direction is open and whose upstream end is blocked are porous. The PM is trapped by the porous thin wall when the exhaust G moves from the inlet-side flow path to the outlet-side flow path through the porous thin wall.

  Further, the fuel nozzle 5 of the light oil burner 2 described above includes a fuel metering pump 12 for sucking light oil from the fuel tank, and compressed air obtained from the air tank of the pneumatic brake device by the light oil discharged from the fuel metering pump 12. A fuel atomizer 13 for mixing and feeding to the fuel nozzle 5 is attached.

  When the particulate filter 3 is regenerated, air extracted from the intake path of the diesel engine is fed into the housing 4 of the light oil burner 2 through the air supply pipe 7. Further, the spark plug 6 and the fuel metering pump 12 are operated, the compressed air stored in the air tank is sent to the fuel atomizer 13, and the light oil discharged from the fuel metering pump 12 is mixed with the compressed air. When fed to the fuel nozzle 5, the light oil is sprayed from the fuel nozzle 5 into the housing 4 of the light oil burner 2.

  In the housing 4, the light oil sprayed from the fuel nozzle 5 is ignited and combusted by the spark emitted from the spark plug 6, and the temperature inside the housing 9 of the particulate filter 3 located on the downstream side of the housing 4 rises. Then, PM collected in the filter body 10 is oxidized and removed, and regeneration of the particulate filter 3 is achieved.

  When regeneration of the particulate filter 3 is completed, the supply of air from the intake passage of the diesel engine into the housing 4 of the light oil burner 2 is stopped, and the operation of the spark plug 6 and the fuel metering pump 12 is interrupted. The inside of the housing 9 of the particulate filter 3 is prevented from being heated.

JP 2009-150279 A

  However, in the exhaust purification device shown in FIG. 4, the fuel metering pump 12 and the fuel atomizer 13 are attached to the fuel nozzle 5 of the light oil burner 2, so that the configuration of the device is complicated and expensive, and maintenance of these devices is required. Inspection is not easy.

  Furthermore, since the compressed air of the pneumatic brake device is used as a pressure source for spraying light oil from the fuel nozzle 5 of the light oil burner 2, depending on the amount of compressed air used for the light oil spray, the compressor of the pneumatic brake device is used. The capacity of the must be increased.

  Further, to apply to a vehicle not equipped with a pneumatic brake device (a vehicle equipped with a hydraulic brake device), it is necessary to newly install a compressor and an air tank, which is not practical.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an exhaust purification device having a simple structure and high reliability.

  In order to achieve the above object, an invention according to claim 1 is directed to a burner having a nozzle for fuel spraying, a spark plug, and an air supply pipe in an exhaust path of a diesel engine equipped with a common rail fuel injection device, and a diesel engine. A common rail fuel injection device having an upstream end via a pressure reducing valve in an exhaust purification device in which a particulate filter having a filter body capable of collecting particulates is incorporated in series from the upstream side to the downstream side in the exhaust flow direction The fuel pressure feed pipe is connected to the discharge port of the fuel supply pump, which is a constituent element, and the downstream end is connected to the fuel nozzle via a metering valve.

  According to the second aspect of the present invention, a burner having a nozzle for fuel spraying, a spark plug, and an air supply pipe and diesel particulates can be collected in the exhaust path of a diesel engine equipped with a common rail fuel injection device. In an exhaust purification device in which a particulate filter having a filter body is incorporated in series from the upstream side to the downstream side in the exhaust flow direction, the upstream end is connected to a common rail that is a component of the common rail type fuel injection device via a pressure reducing valve. A fuel pressure feed pipe connected and connected to the fuel nozzle through a metering valve at the downstream end is provided.

  According to the third aspect of the present invention, a burner having a fuel spray nozzle, a spark plug, and an air supply pipe in the exhaust path of a diesel engine equipped with a common rail fuel injection device, and diesel particulates can be collected. In an exhaust purification device in which a particulate filter having a filter body is incorporated in series from the upstream side to the downstream side in the exhaust flow direction, the fuel supply that is an upstream end component of the common rail fuel injection device via a pressure reducing valve A fuel pressure feed pipe is connected to the fuel line between the discharge port of the pump and the common rail, and the downstream end is connected to the fuel nozzle via a metering valve.

  According to a fourth aspect of the present invention, there is provided a pressure sensor for detecting fuel pressure provided on a common rail, and a control unit for transmitting a command signal to a metering valve connected to the fuel nozzle based on a detection value of the pressure sensor. I have.

  According to the exhaust emission control device of the present invention, the following excellent effects can be obtained.

  (1) In the first aspect of the present invention, the fuel discharged from the fuel supply pump is guided to the fuel nozzle of the burner via the pressure reducing valve, the fuel pressure feeding pipe, and the metering valve, and upstream of the particulate filter. Since the fuel is injected, the air pressure for fuel injection is not required, the structure of the exhaust gas purification device is simplified, and high reliability is obtained for maintenance and inspection.

  (2) In the invention according to claim 2, the fuel accumulated in the common rail is guided to the fuel nozzle of the burner via the pressure reducing valve, the fuel pressure feed pipe, and the metering valve, and injected to the upstream side of the particulate filter. Therefore, air pressure for fuel injection is not required, the structure of the exhaust gas purification device is simplified, and high reliability can be obtained in maintenance and inspection.

  (3) In the invention according to claim 3, the fuel is led from the fuel pipe between the fuel supply pump and the common rail to the fuel nozzle of the burner via the pressure reducing valve, the fuel pressure feeding pipe, and the metering valve. Since injection is performed on the upstream side of the particulate filter, air pressure for fuel injection is not required, the structure of the exhaust gas purification device is simplified, and high reliability can be obtained for maintenance and inspection.

  (4) In the invention described in claim 4, since the command signal is transmitted to the metering valve connected to the fuel nozzle based on the detection value of the pressure sensor provided on the common rail, the particulate filter is regenerated when the particulate filter is regenerated. The curated filter is maintained at an optimum temperature, and regeneration can be completed in a short time without excessive temperature rise.

It is a conceptual diagram which shows the 1st example of the exhaust gas purification apparatus of this invention. It is a conceptual diagram which shows the 2nd example of the exhaust gas purification apparatus of this invention. It is a conceptual diagram which shows the 3rd example of the exhaust gas purification apparatus of this invention. It is a conceptual diagram which shows an example of the conventional exhaust gas purification apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a first example of an exhaust emission control device according to the present invention. A light oil burner 2 and a particulate filter 3 are placed in an exhaust path 1 of a diesel engine 14 from the upstream side in the flow direction of the exhaust G to the downstream side. It is incorporated in series. The diesel engine 14 is equipped with a common rail fuel injection device 15.

  The light oil burner 2 is the same as that shown in FIG. 4 and includes a housing 4, a fuel nozzle 5, a spark plug 6, and an air supply pipe 7. The air supply pipe 7 has a role of extracting air from the discharge port side of the compressor 18 of the turbocharger 17 incorporated in the intake passage 16 of the diesel engine 14 and feeding it into the housing 4. An exhaust pipe 8 is connected to one side of the housing 4 to guide the exhaust G delivered from the diesel engine 14 and passed through the turbine 20 of the turbocharger 17 into the housing 4.

  The particulate filter 3 is also equivalent to that shown in FIG. 4 and has a housing 9 and a filter body 10. The upstream end of the housing 9 in the exhaust G distribution direction is connected to the other end of the housing 4 of the light oil burner 2 described above, and the exhaust pipe 11 connected to the muffler is connected to the downstream end of the housing 9 in the exhaust G distribution direction.

  The common rail type fuel injection device 15 is driven by a diesel engine 14 and sucks light oil from a fuel tank and pressurizes and discharges it, an injector 22 attached to each cylinder of the diesel engine 14, and the fuel supply pump The common rail 23 which accumulates the light oil discharged from 21 and distributes it to the injector 22 and a control unit 24 are the main components.

  The fuel supply pump 21 is configured such that the light oil discharge amount changes in accordance with a command signal 25 from the control unit 24, and the light oil that has passed through the discharge port 26 is supplied to the common rail 23. The fuel supply pump 21 is provided with a relief valve capable of controlling the fuel discharge amount steplessly according to the on / off switching time ratio. When the fuel discharge pressure is lower than the set range, the relief valve is When the fuel supply pump 21 is operated in the closed high load state and the fuel discharge pressure is higher than the set range, the fuel supply pump 21 is operated in the idling state with the relief valve opened. The injector 22 operates individually according to an operation signal from the control unit 24 and injects light oil accumulated in the common rail 23 into each cylinder. In an actual fuel injection device, an in-vehicle engine control unit is used as the control unit 24.

  The exhaust gas purifying apparatus shown in FIG. 1 is characterized in that the upstream end of the fuel pressure feed pipe 27 is connected to the discharge port 26 of the fuel supply pump 21 via the pressure reducing valve 28 and the downstream end of the fuel pressure feed pipe 27 is metered. The pressure sensor 30 for detecting the fuel pressure is provided on the common rail 23 through the valve 29 and connected to the fuel nozzle 5 of the light oil burner 2. And a function of transmitting command signals 32 and 33 for opening and closing the distribution valve 19 and the metering valve 29 during regeneration of the particulate filter 3 are provided in the control unit 24.

  The pressure reducing valve 28 plays a role of reducing the pressure of the light oil accumulated in the common rail 23 to a value suitable for spraying from the fuel nozzle 5. The metering valve 29 plays a role of supplying and shutting off fuel to the fuel nozzle 5.

  Further, in FIG. 1, 34 is an air cleaner mounted on the suction port side of the compressor 18, 35 is an intercooler provided in the intake passage 16, and 36 has an EGR cooler 37 and an EGR valve 38. An EGR pipe for recirculating the exhaust gas G from the manifold to the downstream side of the intercooler 35 of the intake passage 16 is shown.

  In order to regenerate the particulate filter 3, command signals 32 and 33 for opening them are transmitted from the control unit 24 to the distribution valve 19 and the metering valve 29 to activate the spark plug 6. When the distribution valve 19 is opened, the air extracted from the intake passage 16 of the diesel engine 14 is fed into the housing 4 of the light oil burner 2 through the air supply pipe 7. When the metering valve 29 is opened, a part of the light oil discharged from the fuel supply pump 21 is decompressed by the pressure reducing valve 28, and the fuel oil feed pipe 27 and the metering valve 29 are passed through the fuel nozzle 5 to the light oil burner 2. Sprayed into the housing 4.

  In the housing 4, the light oil sprayed from the fuel nozzle 5 is ignited and combusted by the spark emitted from the spark plug 6, and the temperature inside the housing 9 of the particulate filter 3 located on the downstream side of the housing 4 rises. Then, PM collected in the filter body 10 is oxidized and removed, and regeneration of the particulate filter 3 is achieved.

  During regeneration of the particulate filter 3, the fuel pressure in the common rail 23 changes every moment according to the operating conditions of the diesel engine 14. At this time, based on the detection signal of the pressure sensor 30, the control unit 24 commands the opening of the metering valve 29 to be increased when the fuel pressure in the common rail 23 is low, such as when the diesel engine 14 is idling. The signal 33 is corrected, and when the fuel pressure in the common rail 23 is high, such as during high-speed operation of the diesel engine 14, the command signal 33 is corrected so that the opening of the metering valve 29 becomes small. Make the fuel injection amount optimal. Therefore, at the time of regeneration of the particulate filter 3, the particulate filter 3 is maintained at an optimum temperature, and regeneration can be completed in a short time without excessive temperature rise.

  When regeneration of the particulate filter 3 is completed, command signals 32 and 33 for closing them are transmitted from the control unit 24 to the distribution valve 19 and the metering valve 29, and the operation of the spark plug 6 is interrupted. When the distribution valve 19 is closed, the supply of air from the intake passage 16 of the diesel engine 14 into the housing 4 of the light oil burner 2 is stopped, and when the metering valve 29 is closed, the fuel nozzle of the light oil burner 2 is supplied from the fuel supply pump 21. Since the supply of the light oil to 5 stops, the inside of the housing 9 of the particulate filter 3 is not heated.

  In the exhaust emission control device shown in FIG. 1, the light oil discharged from the fuel supply pump 21 of the common rail fuel injection device 15 is supplied to the fuel nozzle 5 of the light oil burner 2 through the pressure reducing valve 28, the fuel pressure feeding pipe 27, and the metering valve 29. Since the air is injected toward the upstream side of the particulate filter 3, the air pressure for fuel injection becomes unnecessary, the structure of the exhaust gas purification device is simplified, and high reliability is obtained for maintenance and inspection.

  FIG. 2 shows a second example of the exhaust emission control device of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts. In the exhaust purification device of FIG. 1 described above, the upstream end of the fuel pressure feed pipe 27 is connected to the discharge port 26 of the fuel supply pump 21 via the pressure reducing valve 28. The exhaust purification device of FIG. 1 is connected to the common rail 23 via the pressure reducing valve 28, and the same operational effects as the exhaust purification device of FIG. 1 can be obtained.

  FIG. 3 shows a third example of the exhaust emission control device of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts. The exhaust purification device of FIG. 3 has an upstream end of a fuel pressure feed pipe 27 connected to a fuel line 39 between a discharge port 26 of a fuel supply pump 21 and a common rail 23 via a pressure reducing valve 28. It is possible to achieve the same operation and effect as those of the exhaust gas purification apparatus.

  It should be noted that the exhaust emission control device of the present invention is not limited to the above-described embodiment, and it is needless to say that changes can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Exhaust path 2 Light oil burner 3 Particulate filter 5 Fuel nozzle 6 Spark plug 7 Air supply pipe 10 Filter main body 14 Diesel engine 15 Common rail type fuel injection device 21 Fuel supply pump 23 Common rail 24 Control unit 25 Opening adjustment signal 26 Discharge amount adjustment Valve 27 Fuel pressure feeding pipe 28 Pressure reducing valve 29 Metering valve 30 Pressure sensor 31 Detection signal 39 Fuel line G Exhaust

Claims (4)

A burner having a nozzle for spraying fuel, a spark plug, and an air supply pipe in an exhaust path of a diesel engine equipped with a common rail fuel injection device, and a particulate filter having a filter body capable of collecting diesel particulates. In the exhaust gas purification device incorporated in series from the upstream side to the downstream side in the exhaust flow direction,
A fuel pressure feed pipe having an upstream end connected to a discharge port of a fuel supply pump that is a component of a common rail type fuel injection device via a pressure reducing valve and a downstream end connected to the fuel nozzle via a metering valve An exhaust purification device characterized by that. A burner having a nozzle for spraying fuel, a spark plug, and an air supply pipe in an exhaust path of a diesel engine equipped with a common rail fuel injection device, and a particulate filter having a filter body capable of collecting diesel particulates. In the exhaust gas purification device incorporated in series from the upstream side to the downstream side in the exhaust flow direction,
A fuel pressure feed pipe having an upstream end connected to a common rail as a component of a common rail type fuel injection device via a pressure reducing valve and a downstream end connected to the fuel nozzle via a metering valve is provided. Exhaust purification device. A burner having a nozzle for spraying fuel, a spark plug, and an air supply pipe in an exhaust path of a diesel engine equipped with a common rail fuel injection device, and a particulate filter having a filter body capable of collecting diesel particulates. In the exhaust gas purification device incorporated in series from the upstream side to the downstream side in the exhaust flow direction,
The upstream end is connected to the fuel line between the discharge port of the fuel supply pump, which is a component of the common rail type fuel injection device, and the common rail via the pressure reducing valve, and the downstream end is connected to the fuel nozzle via the metering valve. An exhaust purification device comprising a connected fuel pressure feed pipe.   3. A pressure sensor for detecting fuel pressure provided on a common rail, and a control unit for transmitting a command signal to a metering valve connected to the fuel nozzle based on a detection value of the pressure sensor. Exhaust gas purification device described in 1.

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