JP2012241624A - Internal combustion engine having burner device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine having a burner device that stably and reliably ignites or burns fuel spray to improve combustion performance.SOLUTION: The internal combustion engine having a burner device includes: an exhaust treatment device disposed in an exhaust gas passage and purifies exhaust gas; a burner device 140 disposed on the upstream side from the exhaust treatment device in the exhaust gas passage, and including a combustion cylinder 142 having a plurality of pores 142C and inserted into the exhaust gas passage, a fuel supply means 144 supplying fuel into the combustion cylinder, a secondary air supply means 146 supplying secondary air into the combustion cylinder, and an igniting means 148; and a control means 200 which controls the amount of fuel to be supplied by the fuel supply means and the amount of secondary air to be supplied by the secondary air supply means so that an air-fuel ratio between the air and fuel in the combustion cylinder is rich, while an air-fuel ratio between the air and fuel in the exhaust gas passage outside the combustion cylinder is lean.

Description

  The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine provided with a burner device for increasing exhaust gas temperature.

In general, in an internal combustion engine such as a diesel engine, fuel is combusted in the engine body, for example, carbon monoxide (CO), unburned hydrocarbon (HC), nitrogen oxide (NO _x ), or particulate (PM). The exhaust gas it contains is exhausted. In order to purify such exhaust gas, an oxidation catalyst for oxidizing carbon monoxide, unburned hydrocarbons, a NO _x catalyst for removing nitrogen oxides, a particulate filter for removing particulates An exhaust treatment device including the above is provided in the internal combustion engine.

  By the way, these exhaust treatment apparatuses require suitable operating conditions in terms of temperature, amount of reducing agent, and the like in order to perform their respective functions. When it is necessary to purify the exhaust gas discharged from the internal combustion engine, it is preferable that this operating condition can be achieved in a short time. For this purpose, in the exhaust gas passage of the internal combustion engine, a burner device is provided on the upstream side of the exhaust treatment device, and the exhaust gas temperature is increased by using the heated gas generated by the burner device. A technique for making a processable active state is known (see, for example, Patent Document 1).

  The burner device described in Patent Document 1 has a combustor head including a fuel / air mixing regulator equipped with a fuel nozzle and a double vortex sprayer, and flows the atomized fuel / air mixture into a combustion chamber. And ignited to mix the combustion mixture with the exhaust gas.

  In the burner device described in Patent Document 1, since it is necessary to always supply air during use, a technique for reducing the size of the device for supplying air by taking in oxygen in exhaust gas has been proposed. (For example, refer to Patent Document 2).

  The burner device described in Patent Document 2 takes in oxygen in exhaust gas and supplies air to the burner combustion chamber, and supplies fuel to the burner combustion chamber in order to stabilize combustion in the burner combustion chamber. Fuel supply means and ignition means for igniting the air-fuel mixture in the burner combustion chamber, the burner combustion chamber being formed inside the bottomed cylindrical body protruding into the exhaust passage, The surface is provided with a plurality of exhaust intake ports for taking the exhaust gas flowing through the exhaust passage into the burner combustion chamber.

JP-A-6-167212 JP 2010-270612 A

  By the way, in the burner device described in the above-mentioned Patent Document 2, the exhaust gas flowing through the exhaust passage can be taken into the burner combustion chamber from a plurality of exhaust intake ports provided on the peripheral surface of the bottomed cylindrical body. Oxygen contained therein is taken into the burner combustion chamber to stabilize the combustion in the burner combustion chamber. As a result, the amount of air to be supplied from the air supply means can be reduced, and the apparatus can be downsized.

  However, in the burner device described in Patent Document 2 described above, the burner combustion chamber is formed inside the bottomed cylindrical body and protrudes into the exhaust passage, so that stable combustion is achieved in the burner combustion chamber. Even if it is carried out, the diffusion of the combustion gas into the exhaust gas is not necessarily sufficient, and if the amount of air and fuel is not appropriate, it is difficult to maintain stable combustion due to a decrease in ignitability or flammability. Turned out to be. Further, in an internal combustion engine, depending on the situation of the exhaust treatment device provided downstream of the burner device, the combustion of fuel in the burner device is not accompanied, in other words, the supply of air is stopped and only the fuel is supplied. In such a case, it has been found that the bottomed cylindrical body projecting into the exhaust passage does not sufficiently diffuse the fuel into the main exhaust gas and has room for improvement.

  In view of the above, an object of the present invention is to provide an internal combustion engine including a burner device that can stably and surely perform ignition or combustion of fuel spray and improve combustion performance.

  An embodiment of an internal combustion engine including a burner device according to the present invention that achieves the above object is provided in an exhaust gas passage, and an exhaust treatment device that purifies exhaust gas, and in the exhaust gas passage, Is also a burner device arranged upstream, a combustion cylinder inserted in the exhaust gas passage and having a plurality of holes, fuel supply means for supplying fuel into the combustion cylinder, and a combustion cylinder in the combustion cylinder A burner device including secondary air supply means for supplying secondary air and ignition means; an air-fuel ratio of air and fuel in the combustion cylinder is rich, and air in an exhaust gas passage outside the combustion cylinder Control means for controlling the amount of fuel supplied from the fuel supply means and the amount of secondary air supplied from the secondary air supply means so that the air-fuel ratio between the fuel and the fuel becomes lean. And

  According to this embodiment, the exhaust gas discharged from the engine through the plurality of holes in the combustion cylinder with respect to the burner device including the fuel supply means, the secondary air supply means and the ignition means in the combustion cylinder. As a part of the gas flows in, the remaining exhaust gas bypasses the burner device. The air containing the exhaust gas flowing into the combustion cylinder and the fuel are contained, the air-fuel ratio of the air and fuel in the combustion cylinder is rich, and the air in the exhaust gas passage outside the combustion cylinder The amount of fuel supplied from the fuel supply means and the amount of secondary air supplied from the secondary air supply means are controlled by the control means so that the air-fuel ratio with the fuel becomes lean, and this rich air-fuel ratio (for example, A mixture of air and fuel (A / F = about 10 to 14) is ignited by the ignition means. As a result, since it is a rich air-fuel ratio, its ignitability and combustion performance are significantly improved. Since the rich air-fuel ratio mixture in the combustion cylinder contains secondary air having a high oxygen concentration, high combustion efficiency can be realized stably. Furthermore, since the ignited combustion gas is discharged through a plurality of holes outside the combustion cylinder having a lean air-fuel ratio, oxygen is sufficiently supplied to the highly combustible flame without causing extinction, etc. The fuel is completely burned.

  Here, in one form of the internal combustion engine provided with the burner device, the combustion cylinder having the plurality of holes is inserted and arranged over the entire diameter in a form orthogonal to the axis in the exhaust gas passage. The body may include a body portion in which the plurality of holes are uniformly formed.

  According to this aspect, when the combustion gas is released from the inside of the combustion cylinder to the outside of the combustion cylinder, the discharge is inserted into the body portion that is inserted and arranged in a form orthogonal to the axis over the entire diameter of the exhaust gas passage. This is done through a plurality of uniformly formed holes. Accordingly, the flame of the combustion gas contacts the air or oxygen outside the combustion cylinder having a lean air-fuel ratio without any deviation, so that complete combustion is performed more reliably without partial extinction.

  In the above embodiment, when the surface area of the portion inserted into the exhaust gas passage in the trunk portion is S, the ratio of the total opening area of the plurality of holes to the surface area S is 75% or less. Preferably there is.

  According to this aspect, the exhaust gas is prevented from flowing excessively into the combustion cylinder through the plurality of holes, so that the air-fuel ratio in the combustion cylinder can be reliably maintained in a rich atmosphere.

  Further, the above-mentioned embodiment includes means for detecting the amount of soot accumulated in the plurality of holes, and when the amount detected by the detection means exceeds a predetermined value, the second air supplied from the secondary air supply means You may have a correction | amendment control means which carries out increase correction | amendment of the secondary air.

  According to this aspect, since the secondary air amount is corrected to increase, gas turbulence in the combustion cylinder is increased and soot is easily removed.

  Moreover, it is preferable that the burner device has a collision member with which the fuel supplied from the fuel supply means collides so as to diffuse the fuel into the combustion cylinder.

  According to this aspect, since the diffusibility of the fuel is further improved, the combustion performance is further improved.

  ADVANTAGE OF THE INVENTION According to this invention, an internal combustion engine provided with the burner apparatus which can ignite or burn fuel spray more stably and reliably and can improve combustion performance can be provided.

1 is a schematic diagram showing the entirety of an internal combustion engine including a burner device according to the present invention. 1 shows a configuration near a burner device, (A) is a cross-sectional view of the first embodiment taken along the axis of the exhaust pipe, (B) is a cross-sectional view taken perpendicular to the axis of the exhaust pipe, (C ) Is a cross-sectional view of the second embodiment taken along the axis of the exhaust pipe, and (D) is a perspective view of those combustion cylinders. It is a flowchart which shows the 1st form of the temperature rising control routine of exhaust gas in embodiment of this invention. It is a flowchart which shows an example of the temperature rising control of exhaust gas in said temperature rising control routine of exhaust gas. 6 is a flowchart showing a second form of an exhaust gas temperature raising control routine in the embodiment of the present invention. It is a flowchart which shows the 3rd form of the temperature rising control routine of exhaust gas in embodiment of this invention. It is a flowchart which shows the 4th form of the temperature rising control routine of exhaust gas in embodiment of this invention.

  Hereinafter, an embodiment of an internal combustion engine provided with a burner device according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an entire internal combustion engine including a burner device according to the present invention. In the following, a diesel engine which is a compression ignition type internal combustion engine will be described as an example. The internal combustion engine includes an engine main body 100. The engine main body 100 includes a combustion chamber 102 for each cylinder, an electronically controlled fuel injection valve 104 for injecting fuel into each combustion chamber 102, an intake manifold 106, and the like. , And an exhaust manifold 108.

  The intake manifold 106 is connected to the outlet of the compressor 112 a of the turbocharger 112 via the intake duct 110. An inlet of the compressor 112 a is connected to an air cleaner 116 via an air flow meter 114. The air flow meter 114 detects the amount of intake air (or exhaust gas flow rate) flowing into the engine body 100 per unit time. Further, an electric throttle valve 118 driven by an electric motor or the like is disposed in the intake duct 110, and an intercooler 120 for cooling the intake air flowing in the intake duct 110 is disposed around the intake duct 110. ing. In the embodiment shown in FIG. 1, the engine cooling water is guided into the intercooler 120, and the intake air is cooled by the engine cooling water.

  On the other hand, the exhaust manifold 108 is connected to the inlet of the exhaust turbine 112 b of the turbocharger 112. The outlet of the exhaust turbine 112 b is connected to the exhaust pipe 122. Further, an EGR passage 124 for performing exhaust gas recirculation (EGR) is disposed between the exhaust manifold 108 and the intake manifold 106. An electronically controlled EGR valve 126 is disposed in the EGR passage 124. Further, an EGR cooler 128 for cooling the EGR gas flowing in the EGR passage 124 is disposed around the EGR passage 124. In the embodiment shown in FIG. 1, the engine cooling water is guided into the EGR cooler 128, and the EGR gas is cooled by the engine cooling water.

  Further, each fuel injection valve 104 is connected to a common rail 132 via a fuel supply pipe 130. The common rail 132 is connected to the fuel tank 136 via an electronically controlled variable discharge amount fuel pump 134. The fuel stored in the fuel tank 136 is supplied into the common rail 132 by the fuel pump 134. The fuel supplied into the common rail 132 is supplied to the fuel injection valve 104 through each fuel supply pipe 130.

  On the other hand, in the exhaust pipe 122 downstream of the outlet of the exhaust turbine 112b, the burner device 140 is disposed downstream of the outlet of the exhaust turbine 112b. As will be described in detail later, the burner device 140 is provided adjacent to the combustion cylinder 142, a fuel supply valve 144 as a fuel supply means for supplying fuel to the exhaust gas flow, and the fuel supply valve 144, and A secondary air supply valve 146 as a secondary air supply means for supplying secondary air and a glow plug 148 as an ignition means for igniting the fuel supplied from the fuel supply valve 144 are provided.

Further, downstream of the burner device 140 is connected to an oxidation catalyst (hereinafter also referred to as DOC (Diesel Oxidation Catalyst)) 160 as an exhaust purification catalyst that is disposed in the exhaust gas passage and purifies the exhaust gas. A particulate filter (hereinafter also referred to as DPF (Diesel Particulate Filter)) 162 for collecting particulates in the exhaust gas is disposed in the exhaust gas passage downstream of the DOC 160. Further, in the downstream of the exhaust gas passage of the DPF162, in the embodiment shown in FIG. 1, chosen as the NOx catalyst reduction type NO _X catalyst (SCR: Selective Catalytic Reduction) with 164 it is arranged, after the upstream A urea addition valve 166 described in detail in FIG. Selective reduction type NO _X catalyst 164, which noble metal such as Pt on the surface of a substrate such as zeolite or alumina supported or, which was supported by the ion exchange of the transition metal such as Cu on the substrate surface, the Examples thereof include those in which a titania / vanadium catalyst (V ₂ O ₅ / WO ₃ / TiO ₂ ) is supported on the substrate surface. Selective reduction type NO _X catalyst 164, the catalyst temperature is in the active temperature region, and, when the urea as a reducing agent is added to reduce and purify NOx. When urea is added to the selective reduction type NO _X catalyst 164 is injected through the urea addition valve 166, ammonia is generated on the catalyst, NOx is reduced by reacting the ammonia with NOx. These DOC160, DPF162 and selective reduction type NO _X catalyst 164 constitute an exhaust treatment apparatus having a function for purifying exhaust.

Here, the DOC 160 reacts unburned components such as HC and CO with O ₂ to make CO, CO ₂ , H ₂ O, and the like. As the catalyst material, for example, Pt / CeO ₂ , Mn / CeO ₂ , Fe / CeO ₂ , Ni / CeO ₂ , Cu / CeO ₂ or the like can be used. As the NOx catalyst in place of the selective reduction type NO _X catalyst 164 described above, the NOx storage reduction catalyst (NSR: NOx Storage Reduction) may be used. This NOx storage reduction catalyst stores NOx in the exhaust gas when the oxygen concentration of the inflowing exhaust gas is high, the oxygen concentration of the inflowing exhaust gas is reduced, and there are reducing components (for example, fuel). Sometimes it has the function of releasing and reducing the stored NOx.

  The DPF 162 may be of a continuous regeneration type in which a catalyst made of a noble metal is supported and the collected fine particles are continuously removed by oxidative combustion. Further, the DPF 162 may be disposed at least downstream of the DOC 160 and upstream or downstream of the NOx catalyst.

  Further, a first temperature sensor 171 for detecting the temperature of the exhaust gas flowing into the burner device 140 is disposed upstream of the burner device 140. Further, a second temperature sensor 172 for detecting the temperature of the burner device 140 is disposed downstream of the burner device 140 (or upstream of the DOC 160) in order to determine the combustion performance of the burner device 140. Further, a third temperature sensor 173 that detects the temperature of the oxidation catalyst 160 is disposed downstream of the oxidation catalyst 160 in order to determine the degree of activity requirement of the exhaust treatment device. In addition, a first pressure sensor 181 for detecting the pressure there is disposed upstream of the burner device 140, and a second upstream sensor for detecting a differential pressure upstream and downstream of the DPF 162 is disposed upstream and downstream of the DPF 162. The pressure sensor 182 and the downstream third pressure sensor 183 are attached.

  Further, as shown in FIG. 1, an electronic control unit (hereinafter referred to as ECU) 200 for controlling various devices according to the operating state of the engine main body 100, the driver's request, and the like is also provided. This ECU 200 inputs and outputs signals to and from the CPU that executes various arithmetic processes related to engine control, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores CPU calculation results, and the like. It is mainly composed of a microcomputer provided with an input / output port for the purpose.

  The ECU 200 includes a crank angle sensor that detects the crank angle of the engine main body 100, in addition to the first to third temperature sensors 171 to 173, the first to third pressure sensors 181 to 183, and the air flow meter 114 described above. Various sensors including an accelerator opening sensor that outputs an electric signal corresponding to the amount of depression of the accelerator pedal are connected via electric wiring, and these output signals are connected to an input port of the ECU 200 via a corresponding AD converter. Entered.

  On the other hand, the output port is connected to the fuel injection valve 104, the electric motor for driving the electric throttle valve 118, the EGR valve 126, the fuel pump 134, and the like through corresponding drive circuits. Further, the output port is connected to various devices including a fuel supply valve 144, a secondary air supply valve 146, a glow plug 148 and a urea addition valve 166 via corresponding drive circuits, and these are connected to the ECU 200. Controlled by. The ECU 200 detects the intake air amount (that is, the exhaust gas amount) Ga based on the output value of the air flow meter 114, detects the engine speed based on the output value of the crank angle sensor, and outputs the output value of the accelerator opening sensor. The required load on the engine main body 100 can be detected based on the above.

  In the present embodiment, the ECU 200 operates the fuel supply valve 144, the secondary air supply valve 146, and the glow plug 148 when performing exhaust gas temperature raising control using the burner device 140. That is, the ECU 200 appropriately opens (turns on) the fuel supply valve 144 and the secondary air supply valve 146, and appropriately injects and supplies fuel and secondary air from the fuel supply valve 144 and the secondary air supply valve 146. In addition, the ECU 200 energizes the glow plug 148 as appropriate to obtain a sufficiently high temperature.

  A first embodiment of the configuration of the burner device 140 and the exhaust pipe 122 in the vicinity thereof will be described with reference to FIGS. In the first embodiment, the burner device 140 includes a cylindrical combustion cylinder 142, and a fuel supply valve 144, a secondary air supply valve 146, and a closed head 142 </ b> A of the combustion cylinder 142 are provided. A glow plug 148 is arranged. The fuel supply valve 144 has one or a plurality of injection ports, and the injection ports are formed so as to inject fuel in a conical shape toward the center of the cylindrical combustion tube 142. In the present embodiment, the fuel injected from the fuel supply valve 144 is light oil that is the fuel of the engine body 100. However, the fuel is not limited to this form, and a fuel different from the fuel of the engine body may be supplied.

  The secondary air supply valve 146 is provided adjacent to the fuel supply valve 144, and is connected to an air supply source such as an air tank or an air pump (not shown).

  The glow plug 148 is arranged to heat or ignite the fuel supplied from the fuel supply valve 144 and the air supplied from the secondary air supply valve 146. The glow plug 148 is formed so that the temperature of the heat generating portion at the front end is increased, and the fuel injection valve 144 is positioned downstream of the fuel supply valve 144 so that the fuel injected from the fuel supply valve 144 contacts the heat generating portion at the front end. Is arranged. The glow plug 148 and the fuel supply valve 144 in the present embodiment are each formed in a rod shape, and are arranged so that the fuel spray from the fuel supply valve 144 appropriately reaches the tip heating portion of the glow plug 148. ing. The glow plug 148 is connected to an in-vehicle DC power source through a booster circuit (not shown), and a heat generating portion at the tip generates heat when energized. The heat generated in the heat generating portion ignites the fuel supplied from the fuel supply valve 144 to generate a flame.

  A plurality of holes 142C are uniformly distributed in the body 142B below the closed head 142A in the cylindrical combustion cylinder 142 of the burner device 140 described above. The body 142B in which the plurality of air holes 142C are formed has exhaust gas passages 122A and 122A having an upper chord or lower chord cross section on both sides of the exhaust pipe 122 as shown in FIG. As formed, the exhaust pipe 122 is disposed so as to be inserted over its entire diameter in a form perpendicular to the axis thereof. The diameters of the exhaust pipe 122 and the combustion cylinder 142 and the opening area of the air holes 142C used here take into account the passage cross-sectional areas of the exhaust gas passages 122A and 122A formed on both sides of the combustion cylinder 142. Thus, it is set so that excessive exhaust gas does not flow into the combustion cylinder 142. For example, when the surface area of the portion inserted into the exhaust pipe 122 in the body 142B of the combustion cylinder 142 is S, the total opening area of the air holes 142C (opening area of one hole × number) is the surface area S. Is preferably 75% or less.

  Next, the exhaust gas temperature raising control by the burner device 140 in the first embodiment will be described. In the first embodiment, after the engine is started, a part of the exhaust gas discharged from the engine is burned by the burner device 140 including the fuel supply valve 144, the secondary air supply valve 146, and the glow plug 148. While flowing into the cylinder 142 through the air holes 142C, the remainder of the exhaust gas passes through exhaust gas passages 122A and 122A formed on both sides of the combustion cylinder 142. The exhaust gas that has passed through the exhaust gas passages 122A and 122A on both sides of the combustion cylinder 142 is the combustion gas released from the burner device 140 through the air holes 142C (or the supply fuel only as will be described later). Etc.) and are led to a downstream exhaust treatment device.

  FIG. 3 is a flowchart showing a first form of the exhaust gas temperature raising control routine. This routine is executed by the ECU 200 at predetermined intervals. Therefore, when the control starts, it is determined in step S301 whether or not the exhaust gas purification performance of the exhaust gas processing device exceeds the required purification rate. The exhaust gas purification performance of the exhaust gas processing apparatus is estimated using, for example, a third temperature sensor 173 downstream of the DOC 160. That is, the temperature of the outlet of the DOC 160 is measured as the floor temperature Tc using the third temperature sensor 173. When the measured bed temperature Tc is lower than a predetermined value, it is considered that the temperature of the oxidation catalyst 160 and the exhaust treatment apparatus typified by the temperature is low (that is, below the light-off temperature) and not activated. The exhaust purification performance is estimated to be below the required purification rate.

  Therefore, when the required purification rate is lower than the required purification rate in step S301, that is, when an affirmative determination is made, the process proceeds to step S302, and it is determined whether or not the operating condition of the burner device 140 is satisfied. Whether or not this operating condition is satisfied is determined, for example, by whether or not the fuel supply valve 144 and the secondary air supply valve 146 in the burner device 140 are in an operable state, and, for example, energization as the engine is started. It is determined by whether or not the glow plug 148 that can start the temperature rises appropriately and is in an ignitable state. When the operation condition of the burner device 140 is established, the process proceeds to step S303, and the ECU 200 executes the exhaust gas temperature increase control in the ECU 200 so that the exhaust gas purification performance of the exhaust gas processing device exceeds the required purification rate. It will be. Note that when a negative determination is made in step S301 or step S302 described above, this temperature increase control routine is temporarily terminated.

  An example of the exhaust gas temperature raising control will be described with reference to the flowchart of FIG. When the exhaust gas temperature increase control is started based on the temperature increase control execution command as in step S303 described above, in step S401, the exhaust gas flow rate, the exhaust gas temperature, and the exhaust processing device temperature discharged from the engine body 100 are set. To be acquired. The exhaust gas flow rate is obtained as the exhaust gas flow rate Ga from the intake air amount based on the output value of the air flow meter 114, for example, and the exhaust gas temperature is exhausted by the first temperature sensor 171 provided upstream of the burner device 140. As the gas temperature Tg and the temperature of the exhaust treatment device, for example, the bed temperature Tc of the oxidation catalyst 160 measured by the third temperature sensor 173 described above is obtained. Then, in the next step S402, the amount of heat necessary for raising the temperature of the exhaust gas is calculated. This required heat quantity is based on the exhaust gas flow rate Ga, the temperature difference between the exhaust gas temperature Tg upstream of the burner device 140 and the bed temperature Tc of the oxidation catalyst 160 downstream of the burner device 140, and the target temperature Tt of the oxidation catalyst 160. Calculated. In step S403, the fuel supply amount qf to be supplied from the fuel supply valve 144 in order to satisfy the above required heat amount, and the predetermined air-fuel ratio inside and outside the combustion cylinder 142, as will be described later, are satisfied. A supply amount ga of secondary air to be supplied from the secondary air supply valve 146 is determined.

Here, in the present embodiment, the air-fuel ratio of air and fuel in the combustion cylinder 142 of the burner device 140 is rich, and the air-fuel ratio of air and fuel in the exhaust gas passage outside the combustion cylinder 142 is lean. Next, a method for determining the fuel supply amount qf and the secondary air supply amount ga will be briefly described. Now, the amount of fuel injected per unit time into the combustion chamber 102 of the engine body 100 by the fuel injection valve 104 is defined as an injected fuel amount Qf. When the ratio of a part of the exhaust gas discharged from the engine main body 100 and flowing in the exhaust pipe 122 flows into the combustion cylinder 142 is an inflow ratio α, the air amount and the fuel amount inside and outside the combustion cylinder 142 are respectively Is expressed as follows. In addition, this inflow ratio (alpha) is dependent on the ratio of the total opening area of the void | hole 142C formed there with respect to the surface area of the trunk | drum 142B of the combustion cylinder 142. FIG.
(1) Air amount in the combustion cylinder 142: Ga × α + ga
(2) Fuel amount in the combustion cylinder 142: Qf × α + qf
(3) Air amount outside the combustion cylinder 142: Ga + ga
(4) Fuel amount outside the combustion cylinder 142: Qf + qf
Therefore, in order to make the air-fuel ratio in the combustion chamber 102 rich, from the above (1) and (2), “(Ga × α + ga) / (Qf × α + qf) ≦ theoretical air-fuel ratio (for example, , = 14.7) ”and the air-fuel ratio outside the combustion chamber 102 is lean, from the above (3) and (4),“ (Ga + ga) / (Qf + qf)> theory The fuel supply amount qf and the secondary air supply amount ga are determined so as to satisfy the “air-fuel ratio”. These values may be calculated based on the above formula or may be obtained in advance through experiments or the like, mapped in correspondence with the variables Ga and Qf, and read from a table stored in the ECU 200.

  Thus, the determined fuel supply amount qf and the secondary air supply amount ga are supplied from the fuel supply valve 144 and the secondary air supply valve 146, respectively, and this rich air-fuel ratio (for example, A / F = 10). A mixture of air and fuel (about ˜14) is ignited by the glow plug 148. Since the combustion cylinder 142 has a rich air-fuel ratio, its ignitability and combustion performance are extremely high. Since the rich air-fuel ratio mixture in the combustion cylinder 142 contains secondary air having a high oxygen concentration, high combustion efficiency is stably achieved. Further, as shown in FIG. 2D, the ignited combustion gas F is discharged through the plurality of holes 142C outside the combustion cylinder 142 having a lean air-fuel ratio, so that the highly combustible flame is formed. Oxygen is sufficiently supplied, and the fuel is completely burned without causing extinguishing.

  Next, a second embodiment of the exhaust gas temperature raising control routine in the embodiment of the present invention will be described with reference to the flowchart of FIG. The second form of the exhaust gas temperature raising control routine is a temperature raising control form suitable for the first form when the engine body 100 is cold or when the catalyst is not warmed up and the activity is low. On the other hand, it is a suitable form for the regeneration of the DPF 162.

  Therefore, when the temperature raising control is started, in step S501, based on the pressures detected by the upstream second pressure sensor 182 and the downstream third pressure sensor 183 provided upstream and downstream of the DPF 162, the DPF 162 Whether or not there is a regeneration request for the DPF 162 is determined based on whether or not the differential pressure exceeds a predetermined value. When there is a regeneration request, the process proceeds to step S502, and it is determined whether or not the operating condition of the burner device 140 is satisfied. As described above, whether or not this operating condition is satisfied is, for example, whether or not the fuel supply valve 144 and the secondary air supply valve 146 in the burner device 140 are in an operable state, and for example, starting the engine, etc. Accordingly, it is determined whether or not the glow plug 148 to be energized is appropriately heated to be ignitable. Then, after waiting for the operating condition of the burner device 140 to be established, the process proceeds to step S503, and the ECU 200 executes the exhaust gas temperature raising control for removing the particulate matter (PM) trapped in the DPF 162. become. This exhaust gas temperature raising control is the same as the exhaust gas temperature raising control shown in FIG. 4 executed in step S303 in the above-described first form of the exhaust gas temperature raising control routine. No duplicate explanation will be given.

  After the exhaust gas temperature raising control in step S503, the process proceeds to step S504, where it is determined whether regeneration of the DPF 162 is completed. This determination is made based on whether or not the differential pressure upstream and downstream of the DPF 162 is lower than a predetermined value based on the pressures detected by the second pressure sensor 182 on the upstream side and the third pressure sensor 183 on the downstream side. Just do it. If it is determined in step S504 that the regeneration of the DPF 162 has not been completed, the process returns to step S502 again, and the above-described exhaust gas temperature increase control is performed until the regeneration of the DPF 162 is completed. When the regeneration is completed, this temperature increase control routine is once terminated.

  Next, a third form of the exhaust gas temperature raising control routine in the embodiment of the present invention will be described with reference to the flowchart of FIG. The third form of the exhaust gas temperature raising control routine is a suitable form for regeneration of the DPF 162 as in the second form, but the second form always involves combustion in the burner device 140. On the other hand, the only difference is that a control routine for allowing the temperature to be increased for regeneration of the DPF 162 without adding combustion in the burner device 140 is added. Therefore, the difference will be described mainly.

  Therefore, when the control starts, it is determined in step S601 whether or not there is a request for regeneration of the DPF 162. When there is a regeneration request, the process proceeds to step S602, and it is determined whether or not the operating condition of the burner device 140 is satisfied. When the operating condition of the burner device 140 is established, the process proceeds to step S603, where the exhaust gas accompanying combustion in the burner device 140 for removing particulate (PM) trapped in the DPF 162 is removed. Temperature increase control is executed in ECU 200.

  On the other hand, if it is determined in step S602 that the operating condition of the burner device 140 is not satisfied, the process proceeds to step S605, where it is determined whether or not the DOC 160 is equal to or higher than the light-off temperature (the temperature at which the oxidation catalyst can operate). When the DOC 160 is equal to or higher than the light-off temperature, the fuel is reformed even when only the fuel is supplied to the DOC 160. For example, a reducing agent such as HC or CO is generated. The temperature of the DOC 160 and thus the DPF 162 can be quickly raised by the oxidation reaction heat of the reducing agent. Accordingly, when the DOC 160 is at or above the light-off temperature, the process proceeds to step S606, where the fuel supply valve 144 supplies only fuel without supplying the secondary air from the secondary air supply valve 146 in the burner device 140. Beginning or continuing, ECU 200 executes the exhaust gas temperature increase control for removing particulate (PM) trapped in DPF 162. Then, after the exhaust gas temperature increase control accompanied by fuel combustion in the burner device 140 in step S603 or the exhaust gas temperature increase control only by the fuel supply in step S606, the process proceeds to step S604, and the above-mentioned first Whether the regeneration of the DPF 162 is completed is determined as in the second mode.

  Next, a fourth embodiment of the exhaust gas temperature raising control routine in the embodiment of the present invention will be described with reference to the flowchart of FIG. The fourth form of the exhaust gas temperature raising control routine is different from the second and third forms described above, and is a form suitable for combustion for regeneration when a burner device or the like is blocked by soot. Because there is. The differences will be explained mainly.

  Therefore, when the control starts, it is determined in step S701 whether or not soot blockage has occurred. The determination is made based on, for example, the pressure detected by the upstream first pressure sensor 181 and the downstream second pressure sensor 182 provided upstream of the burner device 142, upstream and downstream of the burner device 142. The pressure difference is obtained, and it is determined whether or not the air hole 142C of the burner device 142 is blocked by the soot depending on whether or not the pressure difference exceeds a predetermined value. If it is determined that soot blockage has occurred, the process proceeds to step S702, and soot removal combustion is performed to remove this soot. This soot removal combustion is executed with an increase correction control by adding a secondary air amount in a predetermined ratio to the secondary air supply amount ga supplied from the secondary air supply valve 146 per unit time. The Therefore, the gas disturbance in the combustion cylinder 142 is increased, and soot is easily removed. Thereafter, the process proceeds to step S703, and whether or not the removal of the soot blockage is completed is determined by the upstream first pressure sensor 181 and the downstream second pressure sensor 182 provided upstream of the burner device 142 described above. The determination is made based on the detected differential pressure. If it is determined that it has not been completed, the process returns to step S702 again, and the soot removal combustion is continued until the removal is completed.

  In the above embodiment, whether or not soot blockage has occurred is determined based on the differential pressure between the pressures detected by the upstream first pressure sensor 181 and the downstream second pressure sensor 182. However, this determination may be performed by other methods. For example, the fuel from the fuel supply valve 144 does not accompany the cumulative operation time of the engine body 100 with a large amount of soot generation or the supply of secondary air from the secondary air supply valve 146 in the burner device 140 described above. It is also possible that the accumulated control time exceeds the predetermined value when the exhaust gas temperature raising control for removing particulate (PM) trapped in the DPF 162 is performed by supplying only the gas.

  Next, with reference to FIG. 2C, a second embodiment of the vicinity configuration of the burner device 140 will be described. The second embodiment differs from the first embodiment described above only in that a fuel collision member 149 that collides with fuel injected from the fuel supply valve 144 in the combustion cylinder 142 is provided. Therefore, the same structural parts are denoted by the same reference numerals as those used in FIGS. 2A and 2B to avoid redundant description. That is, in the second embodiment, a rectangular plate-shaped fuel collision is formed in such a manner that it crosses the combustion cylinder 142 on the extension passing through the glow plug 148 (strictly, the heat generating portion at the tip) from the outlet of the fuel supply valve 144. A member 149 is provided.

  According to this configuration, a part of the fuel injected and supplied from the fuel supply valve 144 collides with the rectangular plate-shaped fuel collision member 149 and is diffused into the combustion cylinder 142 and reflected toward the glow plug 148, The remaining portion proceeds in a conical shape toward the combustion cylinder 142 as in the first embodiment. Therefore, the diffusibility of the fuel in the combustion cylinder 142 is further improved, so that the ignitability in the glow plug 148 is improved and the combustion performance is further improved.

  In the above-described embodiment, the glow plug is employed as the ignition means. However, the present invention is not limited to this form, and any ignition device capable of igniting the supplied fuel can be employed. For example, a spark plug or a ceramic heater may be employed.

As the exhaust treatment device of this embodiment, DOC, DPF, and NO _X catalyst and has been described by taking as an example, but the invention is not limited to this, the present invention is applied to any device for purifying exhaust be able to. Moreover, you may arrange | position each exhaust processing apparatus individually or in combination.

DESCRIPTION OF SYMBOLS 100 Engine main body 140 Burner apparatus 142 Combustion cylinder 142C Hole 144 Fuel supply valve 146 Secondary air supply valve 148 Glow plug 149 Fuel collision member 160 Oxidation catalyst (DOC)
162 Particulate Filter (DPF)
164 Selective reduction type NO _X catalyst 171 First temperature sensor 172 Second temperature sensor 173 Third temperature sensor 181 First pressure sensor 182 Second pressure sensor 183 Third pressure sensor 200 Electronic control unit (ECU)

Claims (5)

An exhaust treatment device that is disposed in the exhaust gas passage and purifies the exhaust gas;
A burner device disposed upstream of the exhaust treatment device in the exhaust gas passage, the combustion tube being inserted into the exhaust gas passage and having a plurality of holes, and supplying fuel into the combustion tube A burner device comprising: fuel supply means for performing secondary air supply means for supplying secondary air into the combustion cylinder; and ignition means;
Fuel supplied from the fuel supply means so that the air-fuel ratio between air and fuel in the combustion cylinder is rich and the air-fuel ratio between air and fuel in the exhaust gas passage outside the combustion cylinder is lean. Control means for controlling the amount and amount of secondary air supplied from the secondary air supply means;
An internal combustion engine comprising a burner device.   The combustion cylinder having the plurality of holes is inserted and arranged over the entire diameter in a form orthogonal to the axis in the exhaust gas passage, and a body portion in which the plurality of holes are uniformly formed is provided. An internal combustion engine comprising the burner device according to claim 1. The ratio of the total opening area of the plurality of holes to the surface area S is 75% or less, where S is a surface area of a portion of the body portion inserted into the exhaust gas passage. An internal combustion engine comprising the burner device according to Item 1 or 2.   A means for detecting the amount of soot accumulated in the plurality of holes is provided, and when the amount detected by the detection means exceeds a predetermined value, the secondary air supplied from the secondary air supply means is corrected to be increased. An internal combustion engine comprising a burner device according to any one of claims 1 to 3, further comprising correction control means.   The burner apparatus according to any one of claims 1 to 4, wherein the burner apparatus includes a collision member that collides with fuel supplied from the fuel supply means so as to diffuse the fuel into the combustion cylinder. An internal combustion engine.

Images