JP6540213B2 - Burner device and engine system - Google Patents

Description

  The present invention relates to a burner device that raises the temperature of exhaust gas by heat of combustion in a primary combustion chamber and a secondary combustion chamber, and an engine system.

  Conventionally, fuel may be burned in the exhaust gas of a device such as an engine. For example, in the case of a diesel engine, it is necessary to perform a regeneration process of a particulate filter that removes particulate matter such as soot contained in exhaust gas.

  In this regeneration process, the exhaust gas is heated by the oxidation catalyst. However, in Patent Document 1, in order to rapidly raise the oxidation catalyst to the activation temperature, the fuel is burned by the burner device to raise the exhaust gas. The configuration is described. The burner apparatus is provided with a primary combustion chamber and a secondary combustion chamber. The primary combustion chamber is easily ignited because the flow rate of the flowing gas is smaller than that of the secondary combustion chamber. On the other hand, the secondary combustion chamber can burn more fuel because the flow rate of the flowing gas is larger than that of the primary combustion chamber. After ignition in the primary combustion chamber, the fuel injected into the secondary combustion chamber is ignited by receiving the combustion heat in the primary combustion chamber.

JP 2014-47699 A

  As described above, the secondary combustion chamber ignites by receiving combustion heat from the primary combustion chamber, but when it is difficult to ignite in the secondary combustion chamber, such as when the gas flow velocity is too fast, it takes time to raise the exhaust gas It takes it.

  An object of the present invention is to provide a burner device and an engine system capable of improving the ignitability and rapidly raising the temperature of exhaust gas in view of such problems.

In order to solve the above problems, the burner device for raising the temperature of exhaust gas according to the present invention communicates with a first fuel injection unit for injecting fuel, a primary combustion chamber for burning the injected fuel, and the primary combustion chamber. In the secondary combustion chamber, which is communicated via a hole and into which the exhaust gas generated by combustion in the primary combustion chamber flows in from the communication hole, the second fuel injection unit which injects fuel into the secondary combustion chamber, and the secondary combustion chamber The fuel is received opposite to the communication hole, injected into the primary combustion chamber, and dropped into the secondary combustion chamber unburned, and the temperature is raised by the heat of combustion from the primary combustion chamber to cause dripping. And an ignition unit for igniting the fuel.

  The second fuel injection unit may inject fuel toward the ignition unit.

  The fuel cell system may further include an oxygen supply unit that supplies a gas containing oxygen to the secondary combustion chamber.

  The oxygen supply may direct the gas towards the igniter.

  The ignition unit may be provided at an end of the communication hole on the secondary combustion chamber side.

  In order to solve the above-mentioned subject, the engine system of the present invention is provided with the above-mentioned burner device.

  According to the present invention, it is possible to improve the ignitability and rapidly raise the temperature of the exhaust gas.

It is an explanatory view for explaining an exhaust system of an engine system provided with a diesel engine. It is an explanatory view for explaining the structure of a burner device.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values and the like shown in this embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the specification and the drawings, elements having substantially the same functions and configurations will be denoted by the same reference numerals to omit repeated description, and elements not directly related to the present invention will not be illustrated. Do.

  FIG. 1 is an explanatory view for explaining an exhaust system of an engine system S provided with a diesel engine 1. Arrows in FIG. 1 indicate the flow of exhaust gas. As shown in FIG. 1A, the diesel engine 1 is a reciprocating engine, and the air in the cylinder is compressed by the piston to high temperature and pressure, and the fuel such as light oil and heavy oil stored in the fuel tank 2 is The pressure is increased by the fuel pump 3 and the injection pump 4 and injected into the high-temperature, high-pressure air to cause an explosion, and the energy generated by the explosion is converted to motive power. The supercharger 5 is a device that rotates the turbine with the energy of exhaust gas of the diesel engine 1 and compresses intake air to increase the intake pressure to improve the engine output.

  The exhaust pipe 6 is a pipe for discharging the exhaust gas discharged from the exhaust port of the diesel engine 1 to the outside. The exhaust pipe 6 is provided with a diesel particulate filter 7 (DPF: Diesel Particulate Filter).

  The diesel particulate filter 7 is formed of a porous material 7a in which a ceramic or a metal is formed in a honeycomb structure as shown in the longitudinal sectional view of FIG. The particulate matter PM having a size of micron or more is collected, and the particulate matter PM is separated from the exhaust gas.

  Exhaust gas from which the particulate matter PM has been separated is released to the outside. At this time, if the particulate matter PM is excessively deposited on the diesel particulate filter 7, the porous material 7a may be clogged. Clogging causes an increase in exhaust pressure, leading to deterioration of fuel efficiency and reduction of output. Therefore, a diesel oxidation catalyst unit 8 (DOC: Diesel Oxidation Catalyst) is provided on the upstream side of the diesel particulate filter 7 in the exhaust pipe 6.

  The diesel oxidation catalyst unit 8 is provided upstream of the diesel particulate filter 7 in the exhaust pipe 6, and is made of, for example, a catalyst such as platinum or palladium. Then, the oxygen contained in the exhaust gas of the diesel engine 1 is used to catalytically burn the unburned fuel to raise the temperature of the exhaust gas.

  The heated exhaust gas flows to the downstream diesel particulate filter 7, and the particulate matter PM deposited on the diesel particulate filter 7 is burnt (oxidized) and exhausted as carbon dioxide, and the diesel particulate filter 7 Clear the jam (filter regeneration process).

  Such filter regeneration processing is triggered by the clogging of the diesel particulate filter 7 exceeding a predetermined threshold value, and batch processing is performed at a desired timing until a certain degree of clogging is eliminated. It is. However, the temperature of the exhaust gas is low when the diesel engine 1 is started or when the load is low, and the diesel oxidation catalyst unit 8 may not reach the activation temperature.

  In this case, the exhaust gas temperature can not be increased only by the diesel oxidation catalyst unit 8, and the filter regeneration process can not be performed at a desired timing in the diesel particulate filter 7 located downstream thereof. Therefore, in the engine system S, the temperature sensor 9 and the burner device 100 are provided on the upstream side of the diesel oxidation catalyst unit 8 in the exhaust pipe 6.

  The temperature sensor 9 is provided near the upstream side of the diesel oxidation catalyst unit 8 in the exhaust pipe 6, detects the temperature of the exhaust gas flowing into the diesel oxidation catalyst unit 8, and outputs the temperature to the burner device 100. The burner device 100 is connected to the upstream side of the temperature sensor 9 in the exhaust pipe 6 and heats the exhaust gas flowing in the exhaust pipe 6.

  FIG. 2 is an explanatory view for explaining the structure of the burner device 100, and shows a schematic cross-sectional view of the burner device 100 and the pipe 6a. The pipe 6a has a cylindrical shape and extends in the left-right direction in FIG. The flange surface 6b is provided at the left and right ends of the pipe 6a, and the flange face 6b is connected to a pipe (not shown) to form the exhaust pipe 6 described above.

  A cylindrical inner cylinder 10 is provided inside the pipe 6a. In the inner cylinder 10, one end 10a on the left side in FIG. 2 is disposed flush with the flange surface 6b on the left side of the pipe 6a, and the other end 10b is located inside the pipe 6a. That is, the pipe 6a and the inner cylinder 10 form a double pipe.

  Further, an exhaust flow passage 6c is formed inside the pipe 6a and the inner cylinder 10, and as indicated by a white arrow in FIG. 2, the exhaust gas flow from the left to the right in the exhaust flow passage 6c. Are in circulation. Then, inside the inner cylinder 10, a straightening vane (not shown) is disposed. The straightening vane extends parallel to the central axis direction of the inner cylinder 10 and rectifies the flow of exhaust gas flowing inside the inner cylinder 10.

  The outer wall 102 of the burner device 100 is, for example, a rectangular hollow member, and is erected upward in FIG. 2 from the pipe 6 a. Here, the outer wall 102 and the pipe 6a are integrally formed by casting. The end (upper end in FIG. 2) of the outer wall 102 opposite to the pipe 6 a is closed by the upper lid 104. A heat sink 106 is attached to the upper cover 104, and the heat sink 106 promotes heat dissipation from the upper cover 104.

  Inside the outer wall 102, a first partition wall 108 that defines the inside of the outer wall 102 is formed. The first partition wall 108 has, for example, a rectangular plate shape, and is disposed opposite to the left wall 102a on the left side in FIG.

  A bent portion 108 a that is bent toward the left wall 102 a is formed at an end of the first partition wall 108 on the upper lid 104 side. The end of the first partition wall 108 on the side of the pipe 6a is a projecting portion 108b that protrudes to the inside of the pipe 6a, and the other end 10b of the inner cylinder 10 is in contact with the projecting portion 108b.

  An opposing space between the first partition wall 108 and the left wall 102 a is an inflow path 110. The protrusion 108 b is in contact with the inner cylinder 10, and the pipe 6 a side of the inflow path 110 is closed by the inner cylinder 10.

  Moreover, the inflow hole 112 is provided in the edge part by the side of the upper cover 104 among the left wall 102a. The inflow hole 112 is a hole that penetrates the left wall 102 a, and the intake pipe 114 is connected to the outside of the outer wall 102 in the inflow hole 112. A gas (in the present embodiment, air) sent from an unillustrated air supply device (for example, an air pump, a fan, a compressor, etc.) is introduced to the intake pipe 114 and flows into the inflow path 110 from the inflow hole 112. Do.

  Of the internal space of the outer wall 102 partitioned by the first partition wall 108, the side opposite to the inflow path 110 (right side in FIG. 2) is a combustion chamber 116. The combustion chamber 116 is partitioned by the second partition wall 118. The second partition wall 118 has, for example, a rectangular plate shape, and is disposed in the combustion chamber 116, and extends from the first partition wall 108 to the right wall 102b on the right side of the outer wall 102 in FIG. , Spaced apart from the upper lid 104 and disposed substantially in parallel.

  In the combustion chamber 116, the space on the upper lid 104 side partitioned by the second partition wall 118 is the primary combustion chamber 116a, and the space on the exhaust flow path 6c side is the secondary combustion chamber 116b. That is, the secondary combustion chamber 116b is disposed between the primary combustion chamber 116a and the exhaust passage 6c.

  Further, a primary intake port 120 communicating the inflow passage 110 with the primary combustion chamber 116a is provided in the bent portion 108a of the first partition wall 108, and air is allowed to flow from the inflow passage 110 into the primary combustion chamber 116a.

  Similarly, at a portion of the first partition wall 108 that divides the inflow passage 110 and the secondary combustion chamber 116b, a secondary intake port 122 (oxygen supply portion communicating the inflow passage 110 and the secondary combustion chamber 116b) ) And allows air to flow from the inflow path 110 into the secondary combustion chamber 116b.

  Further, a communication hole 124 penetrating from the primary combustion chamber 116a to the secondary combustion chamber 116b is formed in the second partition wall 118, and the primary combustion chamber 116a and the secondary combustion chamber 116b are in communication. Here, the communication hole 124 has a substantially rectangular shape when viewed from the upper lid 104 side.

  The first fuel injection unit 126 and the second fuel injection unit 128 are constituted by a fuel injection device such as an injector having a nozzle, for example, and the respective main body portions are located outside the outer wall 102. The tip of the nozzle of the first fuel injection part 126 penetrates the right wall 102b and protrudes into the primary combustion chamber 116a, and the tip of the nozzle of the second fuel injection part 128 penetrates the right wall 102b and the secondary combustion chamber It projects into 116b.

  Further, in the primary combustion chamber 116a, a flame stabilizing unit 130 is provided in the injection direction forward of the nozzle of the first fuel injection unit 126. The flame stabilizing unit 130 is formed of, for example, a porous material such as wire mesh, sintered metal, metal fiber, glass cloth, ceramic porous body, ceramic fiber, pumice or the like, and the fuel injected from the first fuel injection unit 126 is contained therein. Or temporarily hold on the surface.

  The glow plug 132 is attached to the heat sink 106 described above, and the tip of the glow plug 132 protrudes into the primary combustion chamber 116 a. The tip of the glow plug 132 is covered by the flame stabilizing portion 130.

  The base 134 is a hollow member attached to the inner surface on the primary combustion chamber 116 a side of the upper lid 104, and the tip of the glow plug 132 penetrates, and the flame stabilizing unit 130 is disposed apart from the upper lid 104 and the outer wall 102. It becomes a pedestal for

  The control unit 136 controls the glow plug 132, the first fuel injection unit 126, and the second fuel injection unit 128 based on the output from the temperature sensor 9. For example, when the control unit 136 determines that it is necessary to raise the temperature of the exhaust gas from the output of the temperature sensor 9 or the like, the tip of the glow plug 132 is energized to heat the fuel up to the ignition temperature or higher. The fuel is injected at 126.

  The fuel injected from the first fuel injection part 126 temporarily remains in the flame holding part 130, and reacts with oxygen of air flowing into the primary combustion chamber 116a from the primary intake port 120, and from the tip of the glow plug 132 Ignition by the heat of Thus, when combustion of fuel starts in the primary combustion chamber 116a, the high temperature exhaust gas and unburned fuel associated with the combustion flow into the secondary combustion chamber 116b through the communication hole 124.

  A hole wall 138 is formed along the communication hole 124 on the surface of the second partition wall 118 forming the communication hole 124 on the secondary combustion chamber 116 b side. The hole wall 138 protrudes to the secondary combustion chamber 116b side, and the projection length to the secondary combustion chamber 116b side is longer from the first partition wall 108 side to the right wall 102b side.

  The second fuel injection portion 128 is disposed in the direction in which the hole wall 138 is positioned forward of the injection direction of the nozzle, and after ignition in the primary combustion chamber 116a, the fuel is emitted from the second fuel injection portion 128 by control of the control portion 136. As the fuel is injected, the fuel collides with the hole wall 138 and disperses.

  In the secondary combustion chamber 116b, together with the fuel thus dispersed in the secondary combustion chamber 116b, the unburned fuel flowing from the primary combustion chamber 116a reacts with oxygen contained in the air flowing from the secondary intake port 122. Burn.

  As described above, the combustion chamber 116 includes the primary combustion chamber 116a and the secondary combustion chamber 116b, and the flowability of air in the primary combustion chamber 116a is suppressed more than that of the secondary combustion chamber 116b to improve the ignitability, and the secondary combustion is performed. By making the flow rate of air higher in the chamber 116b than in the primary combustion chamber 116a, a large amount of fuel can be burned.

  The high temperature exhaust gas generated by the combustion of the primary combustion chamber 116a and the secondary combustion chamber 116b flows from the secondary combustion chamber 116b into the exhaust flow passage 6c (pipe 6a). Thus, the temperature of the exhaust gas flowing in the exhaust passage 6c is raised, the temperature of the diesel oxidation catalyst unit 8 is raised to the activation temperature, and the filter regeneration process can be performed in the diesel particulate filter 7.

  By the way, in the secondary combustion chamber 116b, fuel is ignited by receiving combustion heat such as high temperature exhaust gas flowing from the primary combustion chamber 116a. However, as described above, a larger amount of air flows into the secondary combustion chamber 116b than in the primary combustion chamber 116a. In addition, exhaust gas may flow from the exhaust flow path 6c into the secondary combustion chamber 116b, and the gas flow rate in the secondary combustion chamber 116b is higher than that in the primary combustion chamber 116a. Therefore, it takes time for the ignition in the secondary combustion chamber 116b to take time, for example, the gas flow velocity in the secondary combustion chamber 116b is too fast, and it takes time for the temperature rise of the exhaust gas.

  So, in this embodiment, the ignition part 140 is provided in the secondary combustion chamber 116b. The ignition unit 140 has, for example, a rectangular plate shape, and is provided at an end 124 a of the communication hole 124 on the secondary combustion chamber 116 b side. In detail, one end 140 a of the ignition unit 140 is fixed to a portion of the end portion 124 a (that is, the hole wall 138) of the communication hole 124 closest to the right wall 102 b.

  Further, the other end 140 b of the ignition unit 140 is located closer to the exhaust flow path 6 c than the one end 140 a and on the first partition wall 108 side. That is, the ignition unit 140 is disposed to be inclined toward the first partition wall 108 toward the other end 140 b.

  Then, the control unit 136 causes the first fuel injection unit 126 to inject the amount of fuel that can not be burned in the primary combustion chamber 116a. The fuel injected into the primary combustion chamber 116a and dropped into the secondary combustion chamber 116b in an unburned state drips into the secondary combustion chamber 116b through the communication hole 124. The ignition unit 140 receives the dropped fuel.

  Further, the high temperature exhaust gas generated by the combustion in the primary combustion chamber 116a also flows into the secondary combustion chamber 116b through the communication hole 124. The ignition unit 140 is heated by the high temperature exhaust gas. Furthermore, depending on the combustion conditions, the flame generated in the primary combustion chamber 116a may extend into the secondary combustion chamber 116b through the communication hole 124 and may directly heat the igniter 140.

  As described above, since the temperature of the ignition unit 140 is raised by the combustion heat from the primary combustion chamber 116 a, the fuel dropped to the ignition unit 140 through the communication hole 124 is easily ignited by the heat of the ignition unit 140. Therefore, the ignitability can be improved, and the exhaust gas can be rapidly heated.

  In addition, as described above, the second fuel injection unit 128 is disposed in the direction in which the hole wall 138 is positioned forward in the injection direction of the nozzle. In detail, the second fuel injection portion 128 is disposed in the direction in which the fixed portion between the hole wall 138 and the one end 140 a of the ignition portion 140 is located forward of the injection direction of the nozzle. That is, the second fuel injection unit 128 injects the fuel toward the hole wall 138 and the ignition unit 140.

  After confirming the ignition in the primary combustion chamber 116a by the temperature rise based on the output of the temperature sensor 9, the controller 136 confirms the ignition in the secondary combustion chamber 116b from the further temperature rise, the second fuel injection portion 128 Make the fuel injected.

  When fuel is injected in the second fuel injection unit 128, the fuel is already ignited by the ignition unit 140 in the secondary combustion chamber 116b, and the ignition unit 140 is further heated by the flame in the secondary combustion chamber 116b. There is. The fuel injected from the second fuel injection unit 128 collides with the ignition unit 140 and is dissipated while receiving the heat of the ignition unit 140, so it is easy to burn, and the flame in the secondary combustion chamber 116b is further grown. Become.

  At this time, the fuel dropped from the communication hole 124 is ignited and a flame is formed on the front surface of the ignition unit 140 on the communication hole 124 side. Therefore, in the initial stage of flame formation in the secondary combustion chamber 116b, direct injection of fuel to the flame is avoided, and the fuel injected from the second fuel injection unit 128 is the back surface of the ignition unit 140 opposite to the communication hole 124. It is made to clash. As a result, since the fuel collides with the ignition unit 140 and scatters and then moves to the flame side, extinction of the fuel is avoided. Thereafter, the flame grows up and turns to the back side of the ignition unit 140.

  In addition, the secondary intake port 122 faces the other end 140 b of the ignition unit 140, and the air flowing into the secondary combustion chamber 116 b from the secondary intake port 122 flows toward the ignition unit 140. That is, the secondary air intake port 122 guides the air toward the ignition unit 140.

  As described above, in the secondary combustion chamber 116b, since the flame grows from the ignition unit 140 as a starting point, by guiding the air to the ignition unit 140, the air is guided to the flame, and the efficiency of the air is increased. It is possible to cause the reaction to accelerate combustion.

  Although the second fuel injection unit 128 injects the fuel toward the ignition unit 140 in the above-described embodiment, the second fuel injection unit 128 injects the fuel toward members other than the ignition unit 140. You may

  In the embodiment described above, the case of providing the secondary intake port 122 has been described, but the secondary intake port 122 is not provided, and the air and exhaust gas flowing in from the communication hole 124 and the exhaust flow path 6c flow in Exhaust gas may be used for combustion. However, by providing the secondary intake port 122 and guiding the air from the secondary intake port 122 to the secondary combustion chamber 116b, the ignitability in the secondary combustion chamber 116b is improved, and a larger amount of secondary combustion chamber 116b is obtained. It is possible to burn the fuel.

  In the embodiment described above, the case of introducing air into the primary combustion chamber 116a and the secondary combustion chamber 116b has been described, but the gas is not limited to air as long as it is a gas containing oxygen, for example, the exhaust flow passage 6c The exhaust gas led to the inflow path 110 may be led to the primary combustion chamber 116a and the secondary combustion chamber 116b. However, with the configuration in which air is introduced, the temperature rise performance can be improved by increasing the amount of combustion.

  In the above-described embodiment, the secondary intake port 122 guides air toward the ignition unit 140. However, the secondary intake port 122 guides air toward members other than the ignition section 140. It is also good.

  In the embodiment described above, the case where the ignition unit 140 is provided at the end 124a of the communication hole 124 on the secondary combustion chamber 116b side has been described, but the ignition unit 140 is not limited to the other in the secondary combustion chamber 116b. It may be provided at the site. However, by providing the ignition unit 140 at the end 124 a of the communication hole 124 on the secondary combustion chamber 116 b side, the ignition unit 140 can easily receive the fuel dropped from the communication hole 124.

  Moreover, although embodiment mentioned above demonstrated the case where the ignition part 140 was plate shape, the ignition part 140 may be shapes other than plate shape. However, for example, if the amount of fuel stagnation is too large, with the ignition portion 140 having a concave shape, the stagnant fuel will be accumulated as soot. By making the ignition part 140 into a plate shape, the amount of stagnation of the fuel dropped to the ignition part 140 is suppressed to a certain amount, and the accumulation of soot is suppressed. In this case, as described above, by making the ignition part 140 inclined, the amount of fuel staying can be further suppressed, and the accumulation of soot can be further suppressed.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various changes or modifications within the scope of the claims, and it is naturally understood that they are also within the technical scope of the present invention. Be done.

  Industrial Applicability The present invention can be used for a burner device and an engine system for raising the temperature of exhaust gas by combustion heat in the primary combustion chamber and the secondary combustion chamber.

S Engine system 100 Burner device 116a Primary combustion chamber 116b Secondary combustion chamber 122 Secondary intake (oxygen supply part)
124 communication hole 124 a end portion 126 first fuel injection portion 128 second fuel injection portion 140 ignition portion

Claims (6)

A burner apparatus for raising the temperature of exhaust gas, wherein
A first fuel injection unit that injects fuel;
A primary combustion chamber in which the injected fuel burns;
A secondary combustion chamber in communication with the primary combustion chamber via a communication hole, and exhaust gas generated by combustion in the primary combustion chamber flows in from the communication hole;
A second fuel injection unit that injects fuel into the secondary combustion chamber;
The secondary combustion chamber is disposed opposite to the communication hole, receives fuel which is injected into the primary combustion chamber and dropped into the secondary combustion chamber without being burned, and the combustion from the primary combustion chamber An ignition unit for igniting the dropped fuel by raising the temperature by heat;
A burner apparatus comprising:   The burner apparatus according to claim 1, wherein the second fuel injection unit injects fuel toward the ignition unit.   The burner apparatus according to claim 1, further comprising an oxygen supply unit that supplies a gas containing oxygen to the secondary combustion chamber.   The burner apparatus according to claim 3, wherein the oxygen supply unit guides the gas toward the ignition unit.   The burner apparatus according to any one of claims 1 to 4, wherein the ignition unit is provided at an end of the communication hole on the secondary combustion chamber side.   An engine system comprising the burner device according to any one of claims 1 to 5.

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