WO2012137247A1

WO2012137247A1 - Internal combustion engine equipped with burner apparatus

Info

Publication number: WO2012137247A1
Application number: PCT/JP2011/002014
Authority: WO
Inventors: 健一辻本; 三樹男井上
Original assignee: トヨタ自動車株式会社
Priority date: 2011-04-04
Filing date: 2011-04-04
Publication date: 2012-10-11

Abstract

An internal combustion engine equipped with a burner apparatus is provided with: an exhaust processing apparatus disposed in an exhaust gas passageway and configured to purify exhaust gas; a burner apparatus disposed upstream of the exhaust processing apparatus in the exhaust gas passageway and including a fuel supply valve for supplying fuel to an exhaust gas flow, and an igniting apparatus disposed between the exhaust processing apparatus and the fuel supply valve and configured to ignite the fuel supplied from the fuel supply valve; and a rectification catalyst apparatus disposed upstream of the burner apparatus in the exhaust gas passageway. This configuration enables sprayed fuel to be ignited or combusted more stably and reliably, so that preferable operating conditions for the exhaust processing apparatus can be achieved in a short time.

Description

Internal combustion engine with burner device

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 an internal combustion engine such as a diesel engine or a gasoline engine, fuel is combusted in the engine body. For example, carbon monoxide (CO), unburned hydrocarbon (HC), nitrogen oxide (NO _x ), or particulate (PM) Exhaust gas containing is discharged. To purify such exhaust gases, carbon monoxide, unburned hydrocarbons oxidation catalyst for oxidizing the like, NO _X catalyst for removing nitrogen oxides, 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 devices 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 disclosed in Patent Document 1 is disposed on the upstream side of the exhaust treatment device, has a smaller cross-sectional area than the exhaust gas passage of the engine, and a small oxidation catalyst in which a part of the exhaust gas flows. The fuel supply means supplies fuel toward the small oxidation catalyst in the exhaust gas passage, and the ignition means ignites and burns the supplied fuel.

JP 2010-59886 A

Incidentally, an internal combustion engine provided with the burner device described in Patent Document 1 has a glow plug for igniting and burning the fuel supplied from the fuel supply valve. And it is described that such a fuel supply valve supplies or stops fuel toward the small oxidation catalyst, and a glow plug disposed between the fuel supply valve and the small oxidation catalyst heats or stops the surroundings. . More specifically, in the operation region where ignition is possible, the first control state in which the fuel supplied by igniting by the ignition means is heated, or the third in which the fuel is supplied but the heating by the ignition means is stopped. On the other hand, in the operation region where ignition is impossible, control is performed to the second control state in which fuel is supplied and heating is performed by the ignition means but the fuel is not ignited, or the third control state described above. Is disclosed.

As described above, in the internal combustion engine including the burner device described in Patent Document 1, in the operation region where ignition is possible, the operation is controlled so as to be in the first control state or the third control state and cannot be ignited. In the region, by controlling to the second control state or the third control state, the first control state, the second control state, and the third control are performed according to the state of the exhaust gas or the state of the exhaust treatment device. By operating in the state, it is said that a suitable operating condition of the exhaust treatment device can be achieved in a short time.

However, it has been found that, in the burner apparatus as described above, even in an operation region where ignition is possible, ignition may not be performed reliably due to the influence of the exhaust gas flow. That is, the fuel is injected and supplied from the fuel supply valve toward the glow plug. However, since the injected fuel spray is flowed by the influence of the exhaust gas flow, the behavior of reaching the glow plug varies. This is because its ignitability or flammability varies. For example, the exhaust gas flow is disturbed when the exhaust gas flow rate is higher than a predetermined value, the exhaust gas swirl flow when the turbocharger exhaust turbine exists upstream of the burner device, or the exhaust pipe upstream of the burner device Due to the drift of the exhaust gas when there is a bent portion, the arrival behavior of the fuel spray becomes noticeable and the ignitability or combustibility is lowered, making it difficult to maintain stable combustion.

Also, it has been found that even when the temperature of the exhaust gas is low (for example, 150 ° C. or lower) or when the exhaust gas contains moisture, ignition is not reliably performed and stable combustion may not be maintained.

The present invention provides an internal combustion engine provided with a burner device that solves such problems and can stably and reliably ignite or burn fuel spray and achieve suitable operating conditions of an exhaust treatment device in a short time. With the goal.

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 fuel supply means for supplying fuel to the exhaust gas flow, and arranged between the exhaust treatment device and the fuel supply means for igniting the fuel supplied from the fuel supply means And a rectifying catalyst device disposed upstream of the burner device in the exhaust gas passage.

According to this aspect, the exhaust gas discharged from the engine flows into the burner device including the fuel supply means and the ignition means through the rectifying catalyst device disposed upstream of the burner device. become. Since the inflowing exhaust gas is rectified by the rectifying catalyst device, the fuel spray injected from the fuel supply means is not significantly affected by the flow of the exhaust gas and reaches the ignition means stably. As a result, the ignitability or combustibility is improved. Further, even when the temperature of the exhaust gas is low or when the exhaust gas contains moisture, the moisture is removed by the rectifying catalyst device, so that the temperature of the exhaust gas is raised and the ignitability or combustion is increased. The property can be improved more stably. For this reason, the rectifying catalyst device is preferably an oxidation catalyst. Further, the base material supporting the catalyst may be either a straight flow type or a wall flow type as long as the flow at the outlet of the rectifying catalyst device is rectified.

Here, it is preferable that the one aspect further includes a turbulent flow generation structure that is disposed downstream of the ignition means in the exhaust gas passage and upstream of the exhaust treatment device, and causes turbulence of the exhaust gas. . According to this aspect, since the combustion gas ignited downstream of the ignition means is diffused by the turbulent flow generation structure, the generation of smoke can be suppressed. Examples of the turbulent flow generating structure include a turbulent flow generator such as a swirler and a mixer, or a bent structure of the exhaust pipe itself.

In the above embodiment, it is preferable that the distance from the ignition means to the exhaust treatment device or the distance from the turbulent flow generation structure to the exhaust treatment device is longer than the distance from the rectifying catalyst device to the ignition means. According to this configuration, since the distance from the rectifying catalyst device to the ignition means is short, the attenuation of the rectifying effect by the rectifying catalyst device is suppressed and its ignitability or flammability is improved. Since the distance from the generation structure to the exhaust treatment device is longer, the diffusibility of the combustion gas is enhanced and the generation of smoke is suppressed.

Here, the one aspect further includes control means for controlling the fuel supply means and the ignition means, and the control means does not burn the supplied fuel when the flow rate of the exhaust gas in the exhaust gas passage exceeds a predetermined value. As described above, the fuel supply means and the ignition means may be controlled. According to this configuration, the fuel supply means and the ignition means are controlled so that the supplied fuel burns only at a low flow rate condition in which the flow rate of the exhaust gas in the exhaust gas passage does not exceed a predetermined value. And combustion can be performed under flammability.

Further, the one aspect further includes a combustion performance detection means that is disposed downstream of the ignition means in the exhaust gas passage and upstream of the exhaust treatment device, and detects the combustion performance of the ignited fuel, When the combustion performance detected by the combustion performance detecting means is below a predetermined value, the control means for controlling the increase while maintaining the amount of exhaust gas below the predetermined amount, or increasing the oxygen concentration or oxygen amount of the exhaust gas. Control means may be further provided. According to this configuration, when the combustion performance is less than or equal to the predetermined value, the turbulent flow of the combustion gas downstream of the ignition means is increased by controlling the increase while maintaining the amount of the exhaust gas below the predetermined amount, and the combustion Is improved. Alternatively, when the combustion performance is below a predetermined value, by increasing the oxygen concentration or oxygen amount of the exhaust gas, the combustion speed of the combustion gas downstream from the ignition means is increased, turbulence is increased, and the combustibility is increased. More improved.

In the above invention, the exhaust treatment device, the oxidation catalyst, of of the NO _X catalyst and the particulate filter may comprise at least one.

According to the present invention, it is possible to provide an internal combustion engine including a burner device that can stably and surely ignite or burn fuel spray and achieve a suitable operating state of the exhaust treatment device in a short time.

1 is a schematic diagram showing the entirety of an internal combustion engine including a burner device according to the present invention. It is sectional drawing which shows 1st Embodiment of the vicinity structure of a burner apparatus. It is sectional drawing which shows 2nd Embodiment of the vicinity structure of a burner apparatus. It is sectional drawing which shows 3rd Embodiment of the vicinity structure of a burner apparatus. It is sectional drawing which shows 4th Embodiment of the vicinity structure of a burner apparatus. It is a graph which shows the relationship between the flow rate of exhaust gas, and combustion performance. It is a flowchart which shows an example of the temperature rising control 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 equipped with 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 112a of the turbocharger 112 through 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 112b 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.

Furthermore, 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, a rectifying catalyst device 140, which will be described in detail later, is disposed in the exhaust gas passage immediately downstream of the outlet of the exhaust turbine 112b. A burner device 150 including a fuel supply valve 152 as a fuel supply means for supplying fuel to the gas flow and a glow plug 154 as an ignition means for igniting the fuel supplied from the fuel supply valve 152 is disposed. And in this embodiment, the burner apparatus 150 is provided with the turbulent flow generator 156 explained in full detail downstream from the glow plug 154 later.

Further, the downstream of the burner device 150 is connected to an oxidation catalyst 160 as an exhaust purification catalyst that is disposed in the exhaust gas passage and purifies the exhaust gas. In the exhaust gas passage downstream of the oxidation catalyst 160, a particulate filter (hereinafter referred to as DPF) 162 for collecting particulates in the exhaust gas is disposed. 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. The selective reduction type NO _X catalyst 164 has a surface of a base material such as zeolite or alumina supported by a noble metal such as Pt, or a surface of the base material supported by ion exchange of a transition metal such as Cu, 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 oxidation catalysts 160, DPF162 and selective reduction type NO _X catalyst 164 constitute an exhaust treatment apparatus having a function for purifying exhaust.

Here, the oxidation catalyst 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 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 oxidation catalyst 160 and upstream or downstream of the NOx catalyst.

Further, in order to determine the combustion performance in the burner device 150 downstream of the turbulent flow generator 156 (or upstream of the oxidation catalyst 160), a first temperature sensor 171 for detecting the temperature there is disposed. . Further, a second temperature sensor 172 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. Note that a differential pressure sensor (not shown) for detecting the differential pressure across the DPF 162 is attached to the DPF 162.

Furthermore, as shown in FIG. 1, an electronic control unit (hereinafter referred to as ECU) 200 for controlling various devices in accordance with the operating state of the engine 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.

In addition to the first and

second temperature sensors

171 and 172, the differential pressure sensor and the air flow meter 114 described above, the ECU 200 includes a crank angle sensor for detecting the crank angle of the engine body 100, and an electric power corresponding to the amount of depression of the accelerator pedal. Various sensors including an accelerator opening sensor that outputs a signal are connected via electric wiring, and these output signals are input to an input port of the ECU 200 via a corresponding AD converter.

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. Furthermore, the output port is connected to various devices including a fuel supply valve 152, a glow plug 154, and a urea addition valve 166 via corresponding drive circuits, and these are controlled by the ECU 200. 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 152 and the glow plug 154 when the exhaust gas temperature raising control using the burner device 150 is performed. That is, the ECU 200 appropriately opens (turns on) the fuel supply valve 152 to inject fuel from the fuel supply valve 152. In addition, the ECU 200 energizes the glow plug 154 as appropriate so that the temperature is sufficiently high.

Referring to FIG. 2, a first embodiment of the configuration near the burner device 150 will be described. In the first embodiment, the burner device 150 is configured such that a fuel supply valve 152 and a glow plug 154 are arranged with respect to a dome-shaped bulging portion 122A formed in a cylindrical exhaust pipe 122. Yes. The fuel supply valve 152 has one or a plurality of injection ports, and the injection ports are formed so as to supply fuel toward the center of the cylindrical exhaust pipe 122. The injection port of the fuel supply valve 152 in the present embodiment is formed so as to inject fuel in a conical shape. In the present embodiment, the fuel injected from fuel supply valve 152 is light oil that is the fuel of 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 glow plug 154 is disposed so as to heat or ignite the fuel supplied from the fuel supply valve 152. The glow plug 154 is formed such that the temperature of the heat generating portion 154A at the front end is increased, and downstream of the fuel supply valve 152 so that the fuel injected from the fuel supply valve 152 contacts the heat generating portion 154A at the front end. Placed in position. The glow plug 154 and the fuel supply valve 152 in the present embodiment are each formed in a rod shape, and are arranged so that the fuel spray from the fuel supply valve 152 appropriately reaches the tip heating portion 154A of the glow plug 154. Has been. The glow plug 154 is placed in the dome-shaped bulged portion 122A of the exhaust pipe 122 so that the tip heat generating portion 154A is located in a region deviated from the main flow of the exhaust gas indicated by the arrow MS in FIG. Inserted and installed. Note that the glow plug 154 and the fuel supply valve 152 are not limited to a rod shape and may have any shape as long as the above-described requirements are satisfied. The glow plug 154 is connected to an in-vehicle DC power source via a booster circuit (not shown), and the heat generating portion 154A at the tip generates heat when energized. With the heat generated in the heat generating part 154A, the fuel supplied from the fuel supply valve 152 is ignited to generate a flame.

Further, a rectifying catalyst device 140 is disposed upstream of the burner device 150 described above. Although not shown in FIG. 2, the outlet of the exhaust turbine 112b is disposed upstream of the rectifying catalyst device 140 as described above. In the rectifying catalyst device 140 used in the first embodiment, a straight flow type base material 140B is supported on a cylindrical casing 140A, and a noble metal catalyst such as platinum Pt, rhodium Rd, or palladium Pd is supported on the base material. Is an supported oxidation catalyst.

Here, as the rectifying catalyst device 140 used in the present invention, a model in which the base material held in the cylindrical casing 140A described above is a metal base material, or a model in which the base material is a ceramic base material is used. May be used.

In the case of a model that is a metal base material, for example, a metal thin flat plate and a metal thin corrugated plate are laminated, and these are wound into a cylindrical shape and brazed. A catalyst carrier layer made of alumina, for example, is formed on the surface of the substrate. A noble metal catalyst such as platinum Pt, rhodium Rd, or palladium Pd may be supported on the catalyst carrier layer.

On the other hand, in the type that is a ceramic base material, the base material may be formed, for example, in a honeycomb structure from, for example, zeolite or cordierite, and the above-described noble metal catalyst may be supported thereon. Each of the rectifying catalyst devices 140 is a so-called straight flow type having a plurality of independent cells extending linearly from the upstream end to the downstream end. However, the base material supporting the catalyst may be either a straight flow type or a wall flow type as long as the flow at the outlet of the rectifying catalyst device 140 is rectified.

Furthermore, in the first embodiment, a turbulent flow generator 156 is disposed in the exhaust gas passage downstream of the glow plug 154 and upstream of the oxidation catalyst 160. The oxidation catalyst 160 is an exhaust purification oxidation catalyst having a volume larger than that of the rectifying catalyst device 140. The oxidation catalyst 160 includes, for example, a base material 160B having a partition wall extending in the exhaust gas flow direction inside a cylindrical casing 160A. The base material 160B is formed in a honeycomb structure, for example. A coating layer made of, for example, a porous oxide powder is formed on the surface of the substrate 160B, and a noble metal catalyst such as platinum Pt is supported on the coating layer. In the first embodiment, as described above, the first temperature sensor 171 is disposed upstream of the oxidation catalyst 160 and the second temperature sensor 172 is disposed downstream of the oxidation catalyst 160.

Next, the operation of the first embodiment will be described. In the first embodiment, after the engine is started, the exhaust gas discharged from the engine passes through the rectifying catalyst device 140 disposed on the upstream side of the burner device 150, and the fuel supply valve 152 and the glow plug 154 are exhausted. Flows into the burner device 150 including Since the rectifying catalyst device 140 is an oxidation catalyst, the rectifying catalyst device can be used even when the temperature of the exhaust gas is low, such as during cold start, or when the exhaust gas contains moisture. 140 removes such moisture and raises the temperature of the exhaust gas to some extent. At the same time, the exhaust gas flowing into the burner device 150 is rectified by the rectifying catalyst device 140.

For example, when the engine is cold immediately after starting, the exhaust gas passes through an exhaust treatment device typified by a burner device 150, a turbulent flow generator 156, and an oxidation catalyst 160 downstream of the rectifying catalyst device 140. At this time, the temperature Tc of the oxidation catalyst 160 is measured using the second temperature sensor 172. This is to determine whether or not temperature raising control for raising the temperature of the exhaust gas is required. When this measured temperature Tc is lower than a predetermined value, it is considered that the temperature of the exhaust treatment device represented by the oxidation catalyst 160 is low and not activated, so that the exhaust gas is to be activated early. The temperature increase control is executed in the ECU 200. This temperature increase control may be terminated when the temperature Tc of the oxidation catalyst 160 reaches a predetermined value and the temperature increase control request is satisfied. Arbitrary conditions can be adopted for the end timing of the temperature increase control.

An example of the exhaust gas temperature increase control will be described with reference to the flowchart of FIG. When the temperature raising control is started, energization of the glow plug 154 is started in step S701. Then, the process proceeds to step S702, and it is determined whether or not the exhaust gas flow rate Ga exceeds a predetermined value G2. This is determined, for example, by determining the exhaust gas flow rate Ga from the amount of intake air based on the output value of the air flow meter 114, and whether the exhaust gas flow rate Ga is equal to or less than a predetermined value G2 suitable for ignition. When the exhaust gas flow rate Ga is determined to be equal to or less than the predetermined value G2, the process proceeds to step S703, and fuel injection from the fuel supply valve 152 is started. On the other hand, when the exhaust gas flow rate Ga exceeds the predetermined value G2, the flow rate of the exhaust gas is large in the downstream burner device 150 even though it is rectified by the rectifying catalyst device 140, and is ignitable or combustible due to turbulence. Therefore, the process proceeds to step S704 where fuel injection from the fuel supply valve 152 is not performed immediately (indicated in FIG. 7 as “stop fuel injection”).

The fuel is ignited and a flame is generated by injecting fuel from the fuel supply valve 152 to the glow plug 154 heated to a high temperature. That is, the process shifts to the flame generation control state. In the present embodiment, the exhaust gas flowing into the burner device 150 is rectified by the rectifying catalyst device 140 as shown in FIG. 2 as the mainstream MS, so that the fuel spray injected from the fuel supply valve 152 is exhausted. It reaches the heat generating part 154A at the tip of the glow plug 154 stably without being affected by the gas flow. As a result, the ignitability or combustibility is improved. The fuel injection from the fuel supply valve 152 may be continuous or intermittent (pulsed).

In the above-described glow plug 154, the temperature of the glow plug 154 may not increase immediately after energization. Therefore, the fuel injection from the fuel supply valve 152 is performed after the energization of the glow plug 154 is started. It may be performed after a predetermined time for raising the temperature of itself (this state is hereinafter referred to as a standby control state). However, even in this standby control state, the exhaust gas can be gently heated by the amount of heat generated by the glow plug 154, and the temperature of the oxidation catalyst 160 can be slightly increased.

The flame generated by the burner device 150 is, together with the exhaust gas, downstream of the glow plug 154 and upstream of the oxidation catalyst 160 of the exhaust treatment device. In the first embodiment, a swirler or mixer is used. Through the turbulence generator 156 and downstream. Even if unburned HC or the like is generated in the burner device 150 without reaching complete combustion, the turbulent flow generator 156 generates a turbulent flow indicated by an arrow DS in FIG. It is diffused, mixed with oxygen and burned away. Therefore, the occurrence of smoke is suppressed.

In the first embodiment shown in FIG. 2, by operating in the flame generation control state that generates the above-described flame, the temperature of the exhaust gas becomes high, and the high-temperature exhaust gas can be sent downstream. As a result, it is possible to heat the components disposed on the downstream side of such an oxidation catalyst 160, DPF162 or NO _X catalyst 164, in a short time. Accordingly, when the oxidation catalyst 160 is lower than the activation temperature, the temperature can be raised to the activation temperature in a short time, and when the oxidation catalyst 160 is higher than the activation temperature, the temperature is raised in a short time. Thus, the oxidation ability of the catalyst can be increased.

Furthermore, the fuel is reformed by generating a flame, and a reducing agent such as HC or CO is generated. When this reducing agent is sent to the downstream oxidation catalyst 160, when the oxidation catalyst 160 is at an activation temperature or higher, the temperature of the oxidation catalyst 160 can be quickly raised by the oxidation reaction heat of the reducing agent.

Next, with reference to FIG. 3, a second embodiment of the configuration near the burner device 150 will be described. This second embodiment is different from the first embodiment described above in the distance from the rectifying catalyst device 140 to the glow plug 154 as the ignition means, the distance from the glow plug 154 to the exhaust treatment device, or turbulent flow. Since the only difference is that the relationship with the distance from the generator 156 to the exhaust treatment device is determined, the same structural parts are denoted by the same reference numerals to avoid redundant description.

That is, in the second embodiment, the most upstream of the exhaust treatment device from the glow plug 154 is larger than the distance D from the outlet of the rectifying catalyst device 140 to the glow plug 154 (strictly speaking, the heat generating portion 154A at the tip). The exhaust passage is set so that the distance d1 to the oxidation catalyst 160 or the distance d2 from the turbulent flow generator 156 to the most upstream oxidation catalyst 160 of the exhaust treatment device is longer.

According to this configuration, since the distance D from the rectifying catalyst device 140 to the glow plug 154 is short, attenuation of the rectifying effect by the rectifying catalyst device 140 is suppressed and its ignitability or combustibility is improved. Since the distance d1 from the plug 154 to the uppermost oxidation catalyst 160 of the exhaust treatment device or the distance d2 from the turbulent flow generator 156 to the uppermost oxidation catalyst 160 of the exhaust treatment device is longer, the diffusion of the combustion gas Performance is enhanced and the occurrence of smoke is suppressed.

Next, with reference to FIG. 4, a third embodiment of the configuration near the burner device 150 will be described. In the third embodiment, the turbulent flow generator 156 such as a swirler or a mixer is used as the turbulent flow generation structure in the first and second embodiments described above, whereas the exhaust pipe 122 that forms an exhaust passage is used. Since the only difference is that the bent pipe 122B is used, the same reference numerals are assigned to the same structural parts to avoid redundant description.

According to this configuration, the drift of the exhaust gas occurs in the bent pipe 122B of the exhaust pipe 122 that forms the exhaust passage, and thereby the turbulence in the exhaust gas flow occurs. Therefore, as in the case of the turbulent flow generator 156, unburned HC generated in the burner device 150 is conveniently diffused, mixed with oxygen, and removed by combustion, so that the generation of smoke is suppressed. .

Here, FIG. 6 shows a graph for explaining the relationship between the exhaust gas flow velocity (proportional to the flow rate) and the combustion performance. The horizontal axis is the exhaust gas flow velocity (flow rate), and the vertical axis is the combustion performance. As shown in this graph, when the exhaust gas flow velocity V is lower than the first predetermined value V1 and exceeds the second predetermined value V2 larger than the first predetermined value V1, the combustion performance is all. descend. The exhaust gas flow velocity V described here corresponds to the above-described exhaust gas flow rate Ga having a proportional relationship, and the second predetermined value V2 corresponds to the above-described predetermined value G2 of the exhaust gas flow rate.

Therefore, in the first to third embodiments described above, this decrease in combustion performance is detected by the first temperature sensor 171 as combustion performance detection means provided upstream of the oxidation catalyst 160, and the flow velocity V of the exhaust gas is determined. Control is performed so as to exceed the first predetermined value V1. Specifically, when the exhaust gas temperature downstream of the burner device 150 detected by the first temperature sensor 171 is equal to or lower than a predetermined value, it is determined that the combustion performance has deteriorated, and the flow rate Ga of the exhaust gas is set to a predetermined value G2. The increase control is performed while maintaining the following. That is, the exhaust gas flow rate Ga is controlled to increase so that the exhaust gas flow rate Ga exceeds a predetermined value G1 corresponding to the first predetermined value V1 of the exhaust gas flow velocity V, so that the combustion performance is improved.

The increase control can be performed, for example, by adjusting the opening degree of the electric throttle valve 118 or by adjusting the EGR valve 126 arranged in the recirculation flow path of the engine body 100. For example, the flow rate of the exhaust gas flowing into the burner device 150 can be increased by temporarily reducing the exhaust gas recirculation flow rate. This increase control is performed by controlling the above-described electric throttle valve 118 or EGR valve 126 by the ECU 200.

Also, the deterioration of the combustion performance is caused by the low oxygen concentration or oxygen amount of the exhaust gas. Therefore, in the fourth embodiment shown in FIG. 5, to cope with this, the burner device 150 is provided with an air supply valve 155 connected to an air supply source as an air supply means. Similarly to the above-described embodiment, when the temperature downstream of the burner device 150 detected by the first temperature sensor 171 is equal to or lower than a predetermined value, air is supplied from the air supply valve 155, assuming that the combustion performance is degraded. As a result, the oxygen concentration of the exhaust gas is increased.

As described above, when air is supplied from the air supply valve 155 to increase the oxygen concentration or the oxygen amount of the exhaust gas when the combustion performance is less than or equal to the predetermined value, the heat generating portion 154A of the glow plug 154, that is, the ignition source The combustion speed in the vicinity is improved, and the turbulent flow DS of the exhaust gas is increased by improving the speed of combustion diffusion downstream thereof, thereby further improving the combustibility.

In the above description, the glow plug is adopted 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 adopted. For example, a spark plug or a ceramic heater may be employed.

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

Furthermore, in the present embodiment, a diesel engine is taken as an example of the internal combustion engine, but the present invention can also be applied to a spark ignition internal combustion engine (gasoline engine) equipped with an optional burner device. However, in this case, it is preferable to provide a three-way catalyst in the exhaust gas passage, and these oxidation catalyst, NOx catalyst, DPF and three-way catalyst correspond to the exhaust treatment apparatus of the present invention.

DESCRIPTION OF SYMBOLS 100 Engine body 118 Electric throttle valve 122 Exhaust pipe 126 EGR valve 140 Rectification catalyst device 150 Burner device 152 Fuel supply valve 154 Glow plug 156 Turbulence generator 160 Oxidation catalyst 162 Particulate filter (DPF)
164 Selective reduction type NO _X catalyst 166 Urea addition valve 171 First temperature sensor 172 Second temperature sensor 200 Electronic control unit (ECU)

Claims

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 fuel supply unit supplying fuel to the exhaust gas flow, and disposed between the exhaust treatment device and the fuel supply unit And an ignition means for igniting the fuel supplied from the fuel supply means,
An internal combustion engine comprising a burner device, comprising: a rectifying catalyst device disposed upstream of the burner device in an exhaust gas passage.
2. The exhaust gas passage further comprising a turbulent flow generation structure that is disposed downstream of the ignition means and upstream of the exhaust treatment device and causes turbulence of the exhaust gas. An internal combustion engine comprising the burner device described in 1.
The internal combustion engine having a burner device according to claim 1 or 2, wherein a distance from the ignition means to the exhaust treatment device is longer than a distance from the rectifying catalyst device to the ignition means.
3. An internal combustion engine comprising a burner device according to claim 2, wherein a distance from the turbulent flow generation structure to the exhaust treatment device is longer than a distance from the rectifying catalyst device to the ignition means.
And further comprising control means for controlling the fuel supply means and the ignition means,
The control means controls the fuel supply means and the ignition means so that the supplied fuel does not burn when the flow rate of the exhaust gas in the exhaust gas passage exceeds a predetermined value. An internal combustion engine comprising the burner device according to any one of 4 above.
In the exhaust gas passage, further comprising a combustion performance detection means that is disposed downstream of the ignition means and upstream of the exhaust treatment device and detects the combustion performance of the ignited fuel,
3. A control means for controlling the increase while maintaining the amount of exhaust gas below a predetermined amount when the combustion performance detected by the combustion performance detecting means is below a predetermined value. An internal combustion engine comprising the burner device described in 1.
In the exhaust gas passage, further comprising a combustion performance detection means that is disposed downstream of the ignition means and upstream of the exhaust treatment device and detects the combustion performance of the ignited fuel,
When the combustion performance detected by the combustion performance detection means is less than a predetermined value, the control apparatus further includes a control means for controlling to increase the oxygen concentration or oxygen amount of the exhaust gas while maintaining the amount of the exhaust gas below the predetermined amount An internal combustion engine comprising the burner device according to claim 1 or 2.