JP4393858B2 - Auxiliary equipment for exhaust aftertreatment equipment - Google Patents

Description

  The present invention relates to an auxiliary device for an exhaust aftertreatment device for an internal combustion engine.

  In recent years, various exhaust aftertreatment devices have been developed to remove various substances contained in the exhaust gas of an internal combustion engine. As this type of device, an exhaust aftertreatment device equipped with a filter for removing diesel particulate (PM) contained in the exhaust of a diesel engine has been put into practical use. For example, an apparatus having a configuration in which an oxidation catalyst for raising the exhaust temperature of a diesel engine and a filter for collecting PM is used. The exhaust aftertreatment device using this oxidation catalyst has an advantage that fuel efficiency can be improved because the exhaust temperature is raised by oxidation. An exhaust aftertreatment device equipped with this type of filter becomes clogged when the amount of PM collected by the filter reaches a predetermined amount, making it difficult for exhaust to pass through. Therefore, in general, regeneration by an electric heater, regeneration by a catalyst, and regeneration by a light oil burner are used as a regeneration method of the filter.

  Regeneration with an electric heater is not suitable for a filter having a high thermal conductivity in which heat dissipation is increased due to the limitation of power supply. The regeneration by the catalyst does not function because the catalyst is not activated under the driving condition where the exhaust temperature is low. In such a case, the catalyst is activated by increasing the exhaust temperature with a burner or the like. Regeneration with a light oil burner has the advantage that it can be regenerated in a short time due to its high output, and it has the advantage of being efficient because it directly burns fuel and converts it into heat, so the light oil burner is an important function in filter regeneration one of. There are two types of burners: a spray burner that injects fuel directly from a nozzle and burns it, and a premix burner that heats and evaporates the fuel and mixes it with air before burning.

  By the way, in an exhaust aftertreatment device that combines an oxidation catalyst and a PM trapping filter, regeneration of the filter burns PM using a light oil burner under conditions where the catalyst is activated (300 ° C or higher). It is said that it is more efficient to activate the raw material by supplying raw fuel to the oxidation catalyst.

  When the filter is regenerated, a premix burner with good combustion characteristics tends to be selected. However, since the fuel evaporation device is required, the structure is complicated accordingly, and there is a problem that the energy consumption is increased by evaporating the fuel.

  On the other hand, the spray burner has a problem that the atomization of the spray is not sufficient and the combustion characteristics of the light oil burner using light oil as fuel are poor. That is, if the spray particles are large, it takes time to evaporate, so that the mixing with air is worsened, and the ignitability and combustion characteristics are inferior to the premixing type.

  In addition, since there is a limit to the action of raising the exhaust temperature only by the oxidation catalyst, in the exhaust aftertreatment device in which exhaust purification is performed by combining the oxidation catalyst and the filter, the oxidation catalyst is not activated. Use a light oil burner to heat the oxidation catalyst to its activation temperature and then supply fuel as needed, while if the oxidation catalyst is activated, stop supplying fuel A configuration is possible in which an auxiliary device is provided. Since such an auxiliary device can effectively use the catalyst, it is useful for fully utilizing the capacity of the exhaust aftertreatment device.

  However, when the fuel is light oil, atomization is not good with a general pressure nozzle, and it is doubtful whether burner combustion will continue stably. In the case of a burner, a combustion chamber (high temperature part) with a disaster protection function is required. When fuel is supplied, most of the fuel adheres to the wall surface of the exhaust pipe, and it is determined that the effect cannot be gasified.

  An object of the present invention is to propose an improved auxiliary device for an exhaust aftertreatment device that can solve the above-mentioned problems in the conventional invention.

  An object of the present invention is to provide an auxiliary device for an exhaust aftertreatment device that functions as a spray burner for regenerating a filter having improved combustion characteristics while improving the atomization characteristics while retaining the characteristics of the spray burner.

  An object of the present invention is to enable efficient regeneration of a filter in an exhaust aftertreatment device using an oxidation catalyst and a filter so that the oxidation catalyst can always be used in an activated state regardless of the exhaust temperature. Another object of the present invention is to provide an auxiliary device for an exhaust aftertreatment device.

A feature of the present invention for solving the above-described problem is that in an auxiliary device for an exhaust aftertreatment device for supplying flame gas to the exhaust aftertreatment device, a housing having an outlet, and a tip provided in the housing A spray nozzle having an injection hole; a first passage for sending air to the spray nozzle; an injector for supplying fuel into the first passage; a heating device provided in the spray nozzle; A conduction path provided in the housing such that one end opening is disposed close to the nozzle hole and the other end opening is connected to the outlet part in order to guide the spray fluid from the nozzle hole to the outlet part; A second passage for sending air into the housing to generate an air flow from the nozzle hole side to the outlet side in the conduction path, and an igniter for igniting fuel in the conduction path It equipped with a door, before The heating device is yield capacity with a slight gap in the spray nozzle, within the gap, the fuel which has flowed into said spray nozzle increases the easy and flow turbulence retained in said spray nozzle There is a means for this.

  The fuel from the injector is sent to the injection nozzle together with the air passing through the first passage, where the temperature is raised by the heating device, and the fuel is easily gasified. The atomized fuel atomized from the spray nozzle is sent to the conduction path and reaches the igniter together with the air 1 from the second passage, where the mixture of atomized fuel and air is ignited, and the flame gas is discharged from the outlet portion. It can be ejected more. As described above, the auxiliary device for the exhaust aftertreatment device functions as a spray burner and can efficiently increase the temperature in the exhaust aftertreatment device.

  It can be set as the structure which arrange | positions a glow plug or a heater inside a spray nozzle as a heating apparatus. The glow plug or the heater may be activated when the apparatus is started, and the operation may be stopped in a stable operation state. It is also possible to operate with an output of the glow plug or heater that is less than an output that completely gasifies the fuel. The flow rate of the air introduced into the spray nozzle can be set to a value smaller than the theoretical air amount required for combustion as a burner. A structure in which a spiral groove, a screw part, a swirler, a metal mesh, or the like is formed or inserted in the outer periphery of the glow plug or heater inside the spray nozzle in order to increase the turbulence of the flow pressure flowing therethrough or to give direction to the flow. You can also

  Various types of spray nozzles can be used. In forms other than the swirl nozzle, the nozzle hole portion of the nozzle may be a multi-hole, and the jet direction may be set in a direction away from the axis. The position of the inlet part where the mixing air from the second passage enters the combustion chamber is set upstream from the nozzle hole part of the spray nozzle, and the mixing air passes through the spray and flows into the combustion chamber. You can also

  By providing an electromagnetic valve in the flow path of the air pump for supplying the mixing air and the air inlet for mixing, the mixing air can be reduced depending on the operating conditions, for example, at the start of the burner or at the time of ignition. You may comprise so that supply can be controlled.

  Moreover, the entrance / exit diameter of a combustion chamber can also be set smaller than a combustion chamber diameter. When setting an igniter and a combustion confirmation apparatus in a combustion chamber, it can be set as the structure installed in a radial direction from the outer peripheral side.

  In the fuel supply by the injector, the fuel flow rate (output) can be controlled by changing the duty ratio and pulse width of the drive pulse signal. Even when the burner is not operated, air can be flowed from the first passage to clean the inside of the spray nozzle, its nozzle hole, or the igniter.

According to the present invention, there is also provided an auxiliary device for an exhaust aftertreatment device for supplying raw fuel or flame gas to the exhaust aftertreatment device, the housing having an outlet, and the tip provided in the housing. A spray nozzle having an injection hole; a passage for sending air to the spray nozzle; an injector for supplying fuel into the passage; a heating device provided in the spray nozzle; A conduction path provided in the housing in such a manner that one end opening is disposed close to the nozzle hole and the other end opening is connected to the outlet for guiding the jet fluid to the outlet; and the spray nozzle And a first air supply means for generating a skirt-like air flow between the jet fluid from the nozzle hole and the inner wall surface of the conduction path. The nozzle hole in the conduction path A second air feeding means for sending air to a space formed between the housing and the conduction path in order to generate an air flow from the outlet to the outlet side, and fuel in the conduction path is ignited An auxiliary device for an exhaust aftertreatment device characterized by comprising an igniter for the purpose is proposed.

  The fuel from the injector is sent to the spray nozzle together with the air passing through the passage, where the temperature is raised by the heating device, and the fuel is easily gasified. The atomized fuel atomized from the spray nozzle is sent to the conduction path and reaches the igniter together with the air from the second air feeding means, where the mixture of atomized fuel and air is ignited, and the flame gas is discharged. It can be ejected from the outlet. As described above, the auxiliary device for the exhaust aftertreatment device functions as a spray burner and can efficiently increase the temperature in the exhaust aftertreatment device. Since the air supplied from the second air feeding means enters the conduction path through the space formed between the housing and the conduction path, the rise in the temperature of the housing due to the fuel heat generated in the conduction path is mitigated. be able to.

  When the atomized fuel from the spray nozzle is supplied as it is from the outlet, the air from the annular discharge port spreads in a skirt shape by supplying air from the first air supply means into the conduction path. The fuel is guided to the outlet portion in a state of being encased by the air expanded in a skirt shape, and the sprayed fuel can be effectively prevented from adhering to the inner layer surface of the conduction path.

  It can be set as the structure which arrange | positions a glow plug or a heater inside a spray nozzle as a heating apparatus. The glow plug or the heater may be activated when the apparatus is started, and the operation may be stopped in a stable operation state. It is also possible to operate with an output of the glow plug or heater that is less than an output that completely gasifies the fuel. The flow rate of the air introduced into the spray nozzle can be set to a value smaller than the theoretical air amount required for combustion as a burner. A structure in which a spiral groove, a screw part, a swirler, a metal mesh, or the like is formed or inserted in the outer periphery of the glow plug or heater inside the spray nozzle in order to increase the turbulence of the flow pressure flowing therethrough or to give direction to the flow. You can also

  Various types of spray nozzles can be used. In forms other than the swirl nozzle, the nozzle hole portion of the nozzle may be a multi-hole, and the jet direction may be set in a direction away from the axis.

  By providing an electromagnetic valve in the first air supply means and / or the second air supply means, it is possible to control the supply of air, for example, at the time of starting the burner or at the time of ignition according to the operating conditions. You may comprise.

  Moreover, the entrance / exit diameter of the combustion chamber formed in the conduction path can be set smaller than the combustion chamber diameter. When setting an igniter and a combustion confirmation apparatus in a combustion chamber, it can be set as the structure installed in a radial direction from the outer peripheral side.

  In the fuel supply by the injector, the fuel flow rate (output) can be controlled by changing the duty ratio and pulse width of the drive pulse signal. Even when the burner is not operated, air can be passed through the passage to clean the inside of the spray nozzle, its nozzle hole, or the igniter.

  According to the present invention, since the fuel evaporation device is unnecessary than the fuel evaporation type premix burner, the inside of the nozzle and the nozzle hole portion can be cleaned with air because of the small size and energy saving, so that a good operation can be ensured and the reliability is improved. An effect such as improvement can be expected. Further, it becomes possible to always use the oxidation catalyst in an activated state according to the operating conditions, and it is possible to reduce the fuel consumption for regenerating the filter by ensuring the effect of increasing the exhaust temperature of the oxidation catalyst. Further, since the inside of the nozzle and the nozzle hole can be cleaned with air, good operation can be ensured and reliability is improved.

  1 to 3 are views showing an embodiment of an auxiliary device according to the present invention used for regeneration of an exhaust aftertreatment device. 1 is a sectional view thereof, FIG. 2 is a left side view of FIG. 1, and FIG. 3 is a sectional view taken along line AA of FIG.

  The auxiliary device 100 is used by being attached to an exhaust aftertreatment device (not shown), and flame gas is supplied to the exhaust aftertreatment device during the filter regeneration mode operation of the exhaust aftertreatment device provided with a filter for collecting PM in the exhaust gas. It is a device for supplying. The auxiliary device 100 includes a housing 4 in which a housing plate 2 is fixed to one end of a cylindrical housing body 1 by all-around welding or the like, and a cover flange 3 is fixed to the other end by a fixing member 5. Is provided with an opening 2A. The opening 2 </ b> A is an opening that forms an outlet for sending flame gas from the auxiliary device 100 to the exhaust aftertreatment device when the auxiliary device 100 is fixed to the exhaust aftertreatment device by the housing plate 2.

  A glow plug 6 is fixed in the mounting hole 3 </ b> A of the cover flange 3. Here, the glow plug 6 is screwed into the mounting hole 3A by a screw groove 6A provided on the outer peripheral surface of the glow plug 6, and the heater portion 6B of the glow plug 6 projects substantially coaxially into the housing 4. . Electric power for heating is supplied to the glow plug 6 from a power source (not shown), thereby heating the heater section 6B.

  A cap-shaped spray nozzle 7 is fixed in the housing 4 so as to cover the heater section 6B, and the heater section 6B is accommodated in the cylindrical space 7A of the spray nozzle 7 with a slight gap. . The heater section 6B is provided as a heating device in the spray nozzle 7, and as will be described later, the temperature of the fuel in the spray nozzle 7 is raised and flows smoothly into the mist. A plurality of nozzle holes 7B communicating with the cylindrical space 7A are formed at the tip of the spray nozzle 7, and a thread groove 7Aa is formed on the inner peripheral surface of the cylindrical space 7A.

    Providing the spiral thread groove 7Aa on the outer periphery of the glow plug 6 inside the spray nozzle 7 makes it easy for the fuel to stay in the spray nozzle 7 and at the same time increases the turbulence of the fluid flow inside. The effect of promoting atomization, increasing the heat receiving efficiency from the glow plug 6, and making the amount of fuel ejection constant (intermittent → continuous) can be expected. Therefore, this portion may be other than the screw shape. For example, a swirl nozzle can be formed by inserting a refractory metal mesh or forming a swirler.

  The cover flange 3 is provided with a first passage 8 having one end communicating with the cylindrical space 7 </ b> A, and an air inlet 9 is provided at the other end of the first passage 8.

  The air introduction port 9 is configured to be able to supply compressed air from an air pump (not shown). The compressed air sent from the air introduction port 9 enters the cylindrical space 7A through the first passage 8 and is injected. It is configured to be fed into the housing 4 from the hole 7B.

  A fuel supply injector 10 is provided so that fuel can be injected into the first passage 8. Fuel that is pressurized by a fuel pump and adjusted to a constant pressure by a pressure regulator is supplied to the injector 10 from a light oil fuel tank. This pump is operated only during operation. 1 to 3, the fuel supply system to the injector 10 is not shown.

  The injector 10 is fixed to a fixing plate 12 fixed to the housing 4 by a fixing member 5 by an appropriate means. The injection port 10 </ b> A of the injector 10 is connected to the first passage 8 by a connection path 13.

  With the above-described configuration, fuel can be injected into the first passage 8 through which air is sent, and fuel can be sprayed from the nozzle hole 7B.

  In order to form a conduction path for guiding the mixed fluid of air and fuel sprayed from the nozzle hole 7B to the opening 2A, a cylindrical tube 19 having both ends opened is provided in the housing 4.

  One end of the cylindrical tube 19 is disposed close to the nozzle hole 7B, and the other end is welded to the housing plate 2 so that the spray fluid from the nozzle hole 7B can be guided to the opening 2A. It has become. Note that the nozzle hole 7B at the tip of the spray nozzle 7 is a multi-hole nozzle other than the swirl nozzle and is formed with an angle at which the jet direction is an axis. Thereby, the spray from the nozzle hole 7 </ b> B collides with the inner wall surface of the cylindrical tube 19.

  A spark plug 20 for igniting the fuel that has entered the cylindrical tube 19 is provided in the cylindrical tube 19, and a combustion chamber is formed in the cylindrical tube 19. Reference numeral 23 denotes a frame rod. A hole into which the spark plug 20 and the frame rod 23 are inserted is formed on the outer peripheral side of the housing body 1. Airtightness is secured by a gasket and the holes are assembled by a fixing plate and a fixing bolt.

  In the present embodiment, the tip of the spray nozzle 7 enters the cylindrical tube 19 at one end of the cylindrical tube 19, and is relatively large between the outer peripheral surface of the spray nozzle 7 and the inner peripheral surface of the cylindrical tube 19. A gap 21 is formed.

  A second passage 22 is provided in the housing body 1 so that air for fuel combustion can be introduced into the cylindrical tube 19 through the gap 21. Air introduced into the second passage 22 by an air pump (not shown) enters the housing 4, enters the cylindrical tube 19 through the gap 21, and is discharged from the opening 2 </ b> A. Note that an electromagnetic valve (not shown) for ON / OFF control is disposed in the flow path connecting the air pump and the second passage 22 so that the air supply from the second passage 22 can be controlled. The air pump can be operated only when it is in operation.

  In the auxiliary device 100, a combustion chamber is formed on the downstream side of the nozzle hole 7B, and secondary air is introduced to the outside of the combustion chamber. Therefore, the air flow path becomes an air layer and has a heat insulating effect. Therefore, combustion heat is prevented from being released to the outside of the burner, and the utilization heat efficiency is improved. In addition, the combustion chamber promotes gasification of the spray and continuity of combustion because the inner wall is in a high temperature state, and even if it becomes a misfire state, a fire type is secured and useful for maintaining it. In addition to supplying air as a swirl flow, mixing of air and a combustion flame can be promoted.

  Further, since the inflow portion of the air from the second passage 22 into the combustion chamber exists upstream from the nozzle hole 7B, the air always passes through the spray and flows into the combustion chamber, and the combustion flame and air are mixed. Is further improved.

  When the total air amount of this air and the air from the first passage 8 is made larger than the theoretical air amount required for burner combustion (λ ≧ 1), the combustion characteristic is 1.6 ≧ λ ≧ when the excess air ratio is λ. 1.2 is preferred. In the DPF burner, since oxygen is present in the exhaust gas of the engine, operation is possible even at λ <1, but there is a possibility that the operation state may change suddenly. Therefore, it is preferable to operate at λ ≧ 1.

  If the diameter of the inlet / outlet of the combustion chamber is smaller than the diameter of the combustion chamber, unburned spray will flow out to the DPF part and be discharged as unburned HC, especially when ignition is not possible at the time of burner start-up. The part remains in the combustion chamber. After that, if combustion is started, the unburned fuel is heated and gasified and burned, so that the exhaust gas is not deteriorated.

  At the time of starting the burner, it is difficult to ignite unless it is in a rich mixture state. Therefore, it is necessary to stop the supply of air from the second passage 22, but in this configuration, the supply of air from the second passage 22 is stopped. Since it is controllable (supply ON / OFF), the above control is possible.

  Since the auxiliary device 100 is configured as described above, the fuel is supplied by operating the injector 10 and the mixture of the sprayed fuel from the spray nozzle 7 and the air from the second passage 22 is ignited by the spark plug 20. Then, the flame gas can be supplied to burn the PM in the filter to regenerate it.

  Moreover, since it becomes the structure which can send only compressed air to the spray nozzle 7 via the 1st channel | path 8, since the inside of the spray nozzle 7, the nozzle hole 7B, and the deposit | attachment in an apparatus can be wash | cleaned with air. Good operation can be secured and reliability is improved.

  Next, the operation of the auxiliary device 100 will be described.

  When the filter is regenerated, the glow plug 6 is energized. For this energization, it is sufficient to heat the inside of the spray nozzle 7 to such an extent that the fuel is easily evaporated. The reason why the atomization of the conventional spray burner is bad is that the viscosity and surface tension, which are physical properties of light oil, are large. This characteristic has a characteristic of decreasing with increasing temperature. In the auxiliary device 100, the fuel temperature is raised by heating with the glow plug 6 to improve the characteristics. In other words, the glow plug 6 is not used for the purpose of vaporizing (gasifying) all of the fuel, but is used for increasing the temperature. Also, if combustion starts and the temperature of the combustion chamber rises, even fuel with poor atomization can be heated in the fuel chamber and instantly gasified to continue good combustion. Therefore, there is no problem even if the energization to the glow plug 6 is stopped.

  Next, the air pump is operated to introduce air from the air inlet 9 into the spray nozzle 7 through the first passage 8. Thereafter, the injector 10 is operated to feed the fuel, and the spray in which the fuel is made into fine particles is ejected from the nozzle hole. At the same time, the spark plug 20 is operated to ignite the particulate fuel. When the ignition signal is detected from the frame rod 23, the operation of the spark plug 20 is stopped, the electromagnetic valve disposed upstream of the second passage 22 is operated, and air is introduced into the housing 4. The discharge amounts of the injector 10 and the air pump are adjusted so that the burner output becomes the target output and the target excess air ratio.

  During steady operation, if the temperature of the inner wall of the cylindrical tube 19 rises sufficiently and is determined to be in a stable state, the energization of the glow plug 6 is stopped. The determination of the stable state can be made based on the operation time. That is, since gasification combustion is performed by heat exchange at the inner wall of the cylindrical tube 19, excessive atomization is not necessary.

  Since the injector 10 is vulnerable to a high temperature environment, the injector 10 cannot be used directly at a high temperature site such as a burner ejection portion. Further, when it is necessary to adjust the fuel output, intermittent injection is performed, so that the injector 10 is not suitable for continuous combustion. For this reason, in the auxiliary device 100, the injector 10 is installed at a location away from the ejection portion where the injection hole 7B of the spray nozzle 7 is located, and a certain amount of dead volume is formed between the injector 10 and the ejection portion. The problem is solved.

  According to this configuration, the atomized fuel ejected from the injector 10 loses pressure energy at the same time as the ejection, and the ejection speed from the nozzle hole is extremely reduced. That is, the spray is dripping from the nozzle hole 7B. Therefore, air is introduced from the second passage 22 and the atomization and outflow speed are obtained by the shearing and jetting effect by the high-speed air flow, and the spray is formed in the direction in which the nozzle hole 7B is formed. Yes. In addition, a large amount of this air is not required, and it is set smaller (λ <1) than the theoretical air amount required for burner combustion.

  In the case of a burner used for filter regeneration, there is a problem that the specification environment is very strict. For example, when fuel remains in the spray nozzle 7, when the exhaust temperature is high, the residual fuel is steamed and deposited as carbon. Further, exhaust gas flows into the spray nozzle 7 and PM or unburned HC adheres. In the worst case, the nozzle hole 7B is blocked.

  In the auxiliary device 100, the residual fuel in the spray nozzle 7 can be reliably discharged by introducing air from the first passage 8 to the spray nozzle 7 even after the burner operation is stopped. In addition, when the burner operation is stopped, the air is introduced into the spray nozzle 7 periodically or in the same way in an operation state with a large amount of PM emission, thereby igniting the spray nozzle 7 and the nozzle hole 7B. The plug 20 and the like can also prevent the exhaust gas from being exposed and obtain a cleaning effect. That is, the reliability can be improved.

  FIG. 4 is an enlarged view of a main part for explaining another configuration of the spray nozzle 7. The spray nozzle 71 shown in FIG. 4 is different from the spray nozzle 7 shown in FIG. 1 in that a swirler 71A for forming a swirl flow is provided instead of a screw groove. Therefore, the same reference numerals are given to the same parts in FIG. 4 as those in FIG. The swirler 71A is press-fitted and fixed in the space 71B in the main body of the spray nozzle 71. The heater portion 6B of the glow plug 6 penetrates the swirler 71A to become the spray nozzle 7, and its tip extends to the vicinity of the injection hole 7B. Yes. Here, only one nozzle hole 7B is provided at the center. The spray from the nozzle hole 7B is ejected with a radiation angle in a conical shape.

  According to this configuration, it is not necessary to provide the thread groove 7Aa in the cylindrical space 7A, the processing of the spray nozzle 71 is simplified, and the cost can be reduced.

  FIG. 5 is an enlarged view of a main part for explaining another configuration of the spray nozzle 7. The spray nozzle 72 shown in FIG. 5 is different from the spray nozzle 7 shown in FIG. 1 in that a mesh 72A made of heat resistant stainless steel is provided in place of the thread groove. Therefore, the same reference numerals are given to the same parts in FIG. 5 as those in FIG. The mesh 72A is disposed near the base of the spray nozzle 72 and is fitted to the outer peripheral surface of the heater 6B. What is indicated by reference numeral 72B is a stopper for positioning the mesh 72A at the position shown in FIG.

  According to this configuration, without providing the thread groove 7Aa in the cylindrical space 7A, when the air and fuel pass through the mesh 72A, the disturbance of the flow of air and fuel is increased and the atomization of the fuel is promoted. Therefore, the processing of the spray nozzle 72 is simplified and the cost can be reduced.

  6 to 8 are views showing other embodiments of the auxiliary device according to the present invention used for activating the exhaust aftertreatment device. 6 is a sectional view thereof, FIG. 7 is a left side view of FIG. 6, and FIG. 8 is a sectional view taken along line AA of FIG.

  The auxiliary device 200 is a device for supplying raw fuel or flame gas to an exhaust aftertreatment device having an oxidation catalyst for raising the exhaust temperature and a filter for collecting PM in the exhaust. Used after being attached to a post-processing device. The auxiliary device 200 includes a housing 204 in which a housing plate 202 is fixed to one end of a cylindrical housing body 201 by all-around welding or the like, and a cover flange 203 is fixed to the other end by a fixing member 205. Is provided with an opening 202A. The opening 202A forms an outlet for sending raw fuel or flame gas from the auxiliary device 200 to the exhaust aftertreatment device when the auxiliary device 200 is fixed to the exhaust aftertreatment device (not shown) by the housing plate 202. It is an opening.

  A glow plug 206 is fixed to the mounting hole 203 </ b> A of the cover flange 203. Here, the glow plug 206 is screwed into the mounting hole 203A by a thread groove 206A provided on the outer peripheral surface of the glow plug 206, and the heater portion 206B of the glow plug 206 protrudes substantially coaxially into the housing 204. . Electric power for heating is supplied to the glow plug 206 from a power source (not shown), whereby the heater unit 206B is heated.

  A cap-shaped spray nozzle 207 is fixed in the housing 204 so as to cover the heater portion 206B, and the heater portion 206B is accommodated in the space 207A of the spray nozzle 207 with a slight gap. A plurality of injection holes 207B communicating with the space 207A are formed at the tip of the spray nozzle 207, and a thread groove 207Aa is formed on the inner peripheral surface of the space 207A.

  Providing the spiral screw groove 207Aa in the spray nozzle 207 makes it easy for the fuel to stay in the spray nozzle 207 and at the same time increases the turbulence of the fluid flow inside the fuel, thus facilitating fuel atomization. In addition, the effect of increasing the heat receiving efficiency from the glow plug 206 and stabilizing the fuel injection amount (intermittent → continuous) can be expected. Therefore, this portion may be other than the screw shape. For example, a swirl nozzle can be formed by inserting a refractory metal mesh or forming a swirler.

  The cover flange 203 is provided with a passage 208 having one end communicating with the space 207 </ b> A, and an air inlet 209 is provided at the other end of the passage 208.

  Compressed air from an air pump (not shown) can be supplied to the air introduction port 209, and the compressed air sent from the air introduction port 209 enters the space 207A through the passage 208, and passes through the nozzle hole 207B. It is configured to be sent out in 204.

  In order to allow fuel to be injected into the passage 208, a fuel supply injector 210 is provided. The injector 210 is supplied with fuel pressurized by a fuel pump from a light oil fuel tank and adjusted to a constant pressure by a pressure regulator. This pump is operated only during operation. 6 to 8, the fuel supply system to the injector 210 is not shown.

  The injector 210 is fixed to a fixing plate 212 fixed to the housing 204 by a fixing member 205 by an appropriate means. The injection port 210 </ b> A of the injector 210 is connected to the passage 208 by a connection path 213.

  With the above-described configuration, fuel can be injected into the passage 208 through which air is sent, and the fuel can be sprayed from the nozzle hole 207B.

  The spray nozzle 207 is covered with a cap member 215, and an annular passage 216 is formed between the spray nozzle 207 and the cap member 215 so as to surround the outer periphery of the tip portion of the spray nozzle 207. That is, the cap member 215 is covered with the spray nozzle 207 so that the tip end portion of the spray nozzle 207 is accommodated in the cylindrical protrusion 215A of the cap member 215 with a slight gap. An annular passage 216 is formed between the inner peripheral surface of the protrusion 215 </ b> A and the outer peripheral surface of the tip of the spray nozzle 207. As a result, an annular discharge port 216A surrounding the outer periphery of the tip of the spray nozzle 207 is formed. The cap member 215 is fixed to the cover flange 203 with a bolt B via a gasket G.

  The annular passage 216 constitutes a part of the passage 217 formed in the cover flange 203, and the passage 217 annularly compresses compressed air introduced from the air inlet 218 provided at the other end of the passage 217. A first air supply unit for feeding into the housing 204 from the discharge port 216A is configured.

  The air from the annular discharge port 216A constitutes an air curtain that spreads in a skirt shape from the tip of the spray nozzle 207, so that the sprayed fuel sprayed from the nozzle hole 207B by this air curtain can be effectively suppressed. .

  In order to form a conduction path for guiding the fluid ejected from the nozzle hole 207B to the opening 202A, a cylindrical tube 219 having both ends opened is provided in the housing 204. One end of the cylindrical tube 219 is disposed close to the injection hole 207B, and the other end is welded to the housing plate 202 at all circumferences. The fluid from the injection hole 207B and the air from the annular passage 216 are supplied to the opening 202A. It can be guided.

  The nozzle hole 207B at the tip of the spray nozzle 207 is a multi-hole nozzle other than the swirl nozzle, and is formed with an angle at which the jet direction is an axis. Thereby, the spray from the nozzle hole 207B collides with the inner wall surface of the cylindrical tube 219 (see FIG. 9). However, when the spray is ejected from the injection hole 207B, if the air is ejected from the injection port 210A, the spray from the injection hole 207B is encased by the air that expands in a skirt shape, and the spray from the injection hole 207B flows into the cylindrical tube 219. Can be prevented from colliding with the inner wall surface (see FIG. 10). That is, an air layer is formed between the inner wall surface of the cylindrical tube 219 and the spray from the injection hole 207B by the air of the injection port 210A, and the spray from the injection hole 207B collides with the inner wall surface of the cylindrical tube 219. Can be prevented.

  A spark plug 220 for igniting the fuel that has entered the cylindrical tube 219 is provided in the cylindrical tube 219, and a combustion chamber is formed in the cylindrical tube 219. Reference numeral 223 denotes a frame rod. A hole into which the spark plug 220 and the frame rod 223 are inserted is formed on the outer peripheral side of the housing main body 201. The gasket is secured with airtightness and assembled with a fixing plate and a fixing bolt.

  In the present embodiment, at one end of the cylindrical tube 219, the tip of the spray nozzle 207 enters the cylindrical tube 219, and relatively between the outer peripheral surface of the cap member 215 and the inner peripheral surface of the cylindrical tube 219. A large gap 221 is formed.

  A passage 222 is provided in the housing body 201 so that air for fuel combustion can be introduced into the cylindrical tube 219 through the gap 221. The passage 222 constitutes a second air supply unit for supplying air introduced by an air pump (not shown) to the space between the housing 204 and the cylindrical tube 219. The passage 222 is a peripheral layer of the housing 204. Thus, it opens at a portion close to the housing plate 202. Thus, the air supplied into the housing 204 enters the cylindrical tube 219 through the gap 221 and is discharged from the opening 202A. In addition, an electromagnetic valve for ON / OFF control is disposed in a flow path connecting the air pump and the first and second air supply units so that the air supply can be controlled. The air pump can be operated only when it is in operation.

  In the auxiliary device 200, a combustion chamber is formed in a cylindrical tube 219 provided on the downstream side of the nozzle hole 207B, and air is introduced from the passage 222 to the outside thereof. An air layer is formed and has a heat insulating effect. Therefore, combustion heat is prevented from being released to the outside of the burner, and the utilization heat efficiency is improved. In addition, since the inner wall of the cylindrical tube 219 in which the combustion chamber is formed is in a high temperature state, the gasification of the spray is promoted and the continuity of the combustion is achieved. Help maintain. In addition to supplying air as a swirl flow, mixing of air and a combustion flame can be promoted.

  In addition, since the inflow portion of air from the passage 222 into the combustion chamber exists upstream from the nozzle hole 207B, the air always passes through the spray and flows into the combustion chamber, and further mixing of the combustion flame and air further occurs. improves.

  When the total air amount of this air and the air from the passage 208 is made larger than the theoretical air amount required for burner combustion (λ ≧ 1), the combustion characteristic is 1.6 ≧ λ ≧ 1. 2 is preferred. The DPF burner can be operated even when λ <1 because oxygen is present in the exhaust of the engine. However, since there is a possibility that the operating state may change suddenly, it is preferable to operate at λ ≧ 1.

  If the diameter of the entrance / exit of the combustion chamber is made smaller than the inside diameter of the combustion chamber, unburned spray will flow out to the DPF part and be discharged as unburned HC, particularly when ignition is not possible at the time of starting the burner. The part remains in the combustion chamber. Thereafter, if combustion is started, the unburned fuel is heated and gasified and burned, so that the exhaust is not deteriorated.

  When the burner is started, it is difficult to ignite unless it is in a rich mixture state, so it is necessary to stop the supply of air from the passage 222, but in this configuration, the supply of air from the passage 222 can be controlled. Therefore, the above control is possible.

  Since the auxiliary device 200 is configured as described above, the injector 210 is actuated to spray only fuel to activate the oxidation catalyst. The spark plug 220 is actuated to ignite the sprayed fuel and flame. Appropriate activation can be performed in accordance with the operating state of the engine at that time, for example, by supplying gas to further activate the oxidation catalyst.

  Thus, the oxidation catalyst can always be used in an activated state regardless of the operating conditions of the internal combustion engine, and the fuel consumption, HC, and CO emissions can be reduced by the effect of the oxidation catalyst.

  Further, since the compressed air can be sent to the spray nozzle 207 via the passage 208, the inside of the spray nozzle 207, the nozzle hole 207B and the deposits in the apparatus can be cleaned with air, which is good. Operation can be ensured and reliability is improved.

  Next, the operation of the auxiliary device 200 will be described. First, the case where the activation state of the oxidation catalyst of the exhaust aftertreatment device is low and the auxiliary device 200 is used as a light oil burner will be described separately at the time of starting and at the time of steady operation.

  At startup, the glow plug 206 is energized to heat the inside of the spray nozzle 207. Next, the air pump is operated to introduce air into the spray nozzle 207 from the air inlet 209. Thereafter, the injector 210 is operated to feed the fuel, and at the same time as the spray is ejected from the nozzle hole, the spark plug 220 is operated to ignite the sprayed fuel. When the ignition signal is detected from the frame rod 223, the operation of the spark plug 220 is stopped, the electromagnetic valve disposed upstream of the passage 222 is operated, air is introduced into the housing 204, and the cylindrical tube 219 is introduced. Shed. The discharge amounts of the injector 210 and the air pump are adjusted so that the burner output becomes the target output and the target excess air ratio.

  During steady operation, if the temperature of the inner wall of the cylindrical tube 219 rises sufficiently and is determined to be in a stable state, the energization of the glow plug 206 is stopped. The determination of the stable state can be made based on the operation time. That is, since gasification combustion is performed by heat exchange at the inner wall of the cylindrical tube 219, excessive atomization is not necessary.

  Next, the case where the oxidation catalyst is activated by using the light oil burner and fuel injection is performed will be described. In order to determine whether or not the oxidation catalyst is in an activated state, it is preferable that a temperature sensor is disposed in the vicinity of the oxidation catalyst and the determination is made based on the measured value. When it is determined that the fuel is sufficiently activated, and when it is determined that fuel injection is necessary for further temperature increase for activation of the oxidation catalyst, the following operation is performed.

  Once the burner combustion is stopped, the fuel injection of the injector 210 is stopped and the fire is completely extinguished. Thereafter, the solenoid valve for air supply to the passage 222 is stopped, and the supply of air is stopped. Next, the solenoid valve is operated to supply air from the passage 222. When the operation of the glow plug 206 is stopped, the energization is resumed, and the operation of the injector 210 and the adjustment of the air pump are performed so that the target fuel supply amount and the target air amount are obtained. The spray angle at the nozzle hole 207B is reduced by the skirt-like air flow from the annular discharge port 216A, and the jet fuel from the nozzle hole 207B does not collide with the inner wall surface of the cylindrical tube 219, and the raw fuel as spray or gas is applied to the oxidation catalyst. Can be supplied.

  The operation when the oxidation catalyst is in the activated state is as follows. A case will be described in which it is determined that the filter is in an active state without using a light oil burner and filter regeneration is necessary. The glow plug 206 is energized to heat the inside of the spray nozzle 207. Air is supplied to the passage 208 and the air inlet 218 at the same time when the air pump is operated. At this time, the air pump is operated so as to obtain a target air amount.

  Thereafter, the fuel injector 210 is operated, and fuel injection is started so as to obtain the target injection amount.

Operation of other fuel supply devices When the auxiliary device 200 is arranged in the exhaust pipe of the engine, the unburnt HC or PM adheres to the spray nozzle 207 due to the exhaust flowing in, and the nozzle nozzle hole is closed. There is a risk of disability. In order to prevent such a problem from occurring, only the air from the passage 208 is continuously injected from the spray nozzle 207 for a while when the operation is stopped, and all the fuel remaining in the spray nozzle 207 is eliminated.

  When not in operation, air is ejected from the spray nozzle 207 and the passage 222 for the purpose of preventing apparatus cleaning and exhaust inflow periodically or in an operating state where the amount of PM emission is large.

  The auxiliary device 200 can also be used as a raw fuel supply device for regeneration of the NOx adsorption catalyst. If the auxiliary device 200 is used, it becomes possible not only to efficiently use the exhaust aftertreatment device including the oxidation catalyst and the PM collection filter, but also to the case of the exhaust aftertreatment device using the NOx catalyst. Is possible.

Sectional drawing which shows one Embodiment of the auxiliary device by this invention. The left view of FIG. AA sectional view taken on the line AA of FIG. The expanded sectional view which shows the modification of the spray nozzle shown in FIG. The expanded sectional view which shows another modification of the spray nozzle shown in FIG. Sectional drawing which shows other embodiment of the auxiliary device by this invention. The left view of FIG. AA line sectional view of Drawing 6. The figure for demonstrating operation | movement of the auxiliary | assistant apparatus of FIG. The figure for demonstrating another operation | movement of the auxiliary | assistant apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing body 2A Opening 2 Housing plate 3 Cover flange 3A Mounting hole 4 Housing 5 Fixing member 6 Glow plug 6A Screw groove 6B Heater part 7 Spray nozzle 7A Cylindrical space 7Aa Screw groove 7B Injection hole 8 1st channel | path 9 Air inlet 10 Injector 10A Injection port 11 Second injector 12 Fixed plate 13 Connection path 15 Cap member 19 Cylindrical tube 20 Spark plug 21 Gap 22 Second passage 23 Frame rod 100 Auxiliary device 201 Housing body 202 Housing plate 203 Cover flange 204 Housing 205 Fixed member 206 Glow plug 207 Spray nozzle 208 Passage 209 Primary air inlet 210 Injector 212 Fixed plate 213 Connection passage 215 Cap member 216 Annular passage 216 Annular discharge port 217 passage 218 air introduction port 219 cylindrical tube 220 spark plug 221 gap 222 third passage 223 frame rod

Claims (7)

In the exhaust aftertreatment device auxiliary device for supplying flame gas to the exhaust aftertreatment device,
A housing having an outlet portion;
A spray nozzle provided in the housing and having a nozzle hole at the tip;
A first passage for sending air to the spray nozzle;
An injector for supplying fuel into the first passage;
A heating device provided in the spray nozzle;
A conduction path provided in the housing such that one end opening is disposed close to the nozzle hole and the other end opening is connected to the outlet part so as to guide the spray fluid from the nozzle hole to the outlet part. When,
A second passage for sending air into the housing to generate an air flow from the nozzle hole side toward the outlet side in the conduction path;
An igniter for igniting the fuel in the conduction path,
The heating device is accommodated in the spray nozzle with a slight gap, in which the fuel that has flowed into the spray nozzle easily stays in the spray nozzle and increases turbulence in the flow. Means for providing an exhaust aftertreatment device auxiliary device An auxiliary device for an exhaust aftertreatment device for supplying raw fuel or flame gas to the exhaust aftertreatment device,
A housing having an outlet portion;
A spray nozzle provided in the housing and having a nozzle hole at the tip;
A passage for sending air to the spray nozzle;
An injector for supplying fuel into the passage;
A heating device provided in the spray nozzle;
A conduction path provided in the housing such that one end opening is disposed close to the nozzle hole and the other end opening is connected to the outlet part in order to guide the jet fluid from the nozzle hole to the outlet part. When,
A first air supply for generating a skirt-like air flow between the jetting fluid from the nozzle hole and the inner wall surface of the conduction path, having an annular discharge port surrounding the outer periphery of the tip portion of the spray nozzle. Supply means;
A second air feeding means for sending air to a space formed between the housing and the conduction path in order to generate an air flow from the nozzle hole side toward the outlet side in the conduction path;
An igniter for igniting the fuel in the conduction path ,
The heating device is accommodated in the spray nozzle with a slight gap, and the fuel that has flowed into the spray nozzle easily stays in the spray nozzle and increases flow disturbance. Means for providing an exhaust aftertreatment device auxiliary device   The auxiliary device for an exhaust aftertreatment device according to claim 1, wherein the exhaust aftertreatment device includes a filter for removing diesel particulates in the exhaust gas.   The exhaust aftertreatment device auxiliary device according to claim 2, wherein the exhaust aftertreatment device includes an oxidation catalyst for raising the exhaust temperature and a PM collecting filter. The heating device is accommodated in the cylindrical space in the spray nozzle with a slight gap, and the fuel that has flowed into the spray nozzle stays in the spray nozzle at the outer periphery of the heating device. The auxiliary device for an exhaust aftertreatment device according to claim 1 or 2 , wherein a spiral screw groove is provided for facilitating the flow and increasing the flow disturbance. The exhaust according to claim 1 or 2 , wherein the fuel flowing into the spray nozzle easily stays in the spray nozzle and the means for increasing the flow disturbance is a refractory metal mesh provided in the gap. Auxiliary device for post-processing equipment. Exhaust fuel flowing in said spray nozzle means for increasing the easy and flow turbulence retained in said spray nozzle, the heating is swirler formed on the outer peripheral portion of the apparatus according to claim 1 or 2, wherein Auxiliary device for post-processing equipment.

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