JP2007315313A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine, capable of preventing fuel injection from becoming unstable, when foreign matter such as soot and heat intrude inside a fuel injection valve for injecting fuel into an exhaust pipe. <P>SOLUTION: This exhaust emission control device of the internal combustion engine has a fuel injector for injecting the fuel into the exhaust pipe on the upstream side of an exhaust emission control member for purifying exhaust gas; and is characterized in that the fuel injector has the fuel injection valve for injecting the fuel into an exhaust passage, and the fuel injection valve has a valve element having a collar part on one end side and having a spring receiving part on the other end side, a valve seat part having a seat surface for seating the collar part of the valve element on the injection direction side of the fuel, and a spring sandwiched by the spring receiving part and the valve seat part and energizing the valve element in the valve closing direction, and the seat surface of the valve seat part is arranged in a tip part of the fuel injection valve, and the valve seat part faces in the exhaust pipe. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an exhaust emission control device for an internal combustion engine. In particular, an exhaust purifying apparatus for an internal combustion engine having a fuel injection device for injecting fuel into the exhaust pipe upstream of the exhaust purifying member of the NO _X catalyst and the like particulate filter disposed in an exhaust pipe.

Conventionally, in exhaust gas discharged from an internal combustion engine such as a diesel engine, it contains nitrogen oxides that may cause environmental pollution (hereinafter referred to as NO _X) and (hereinafter referred to as PM) particulate matter and the like ing.
Among them, in order to purify the exhaust gas by reducing NO _X, NO _X catalyst such as _the NO _X storage reduction catalyst and _the NO _X selective reducing catalyst is used. _The NO _X storage reduction catalyst, the exhaust air-fuel ratio is temporarily occludes NO _X in the exhaust gas when the lean, when the exhaust air-fuel ratio is rich, the hydrocarbon (HC) and carbon monoxide (CO) or the like in the exhaust gas This is a catalyst that decomposes and releases NO _x to reduce and purify. Further, NO _X selective reduction catalyst is a catalyst that selectively reduces and purifies NO _X in the catalyst urea or HC as a reducing agent. When reducing and purifying NO _X using these NO _X catalysts, fuel is injected into the exhaust pipe upstream of the NO _X catalyst in order to make the exhaust air-fuel ratio rich or to mix HC in the exhaust gas. There is a way to do it.

  In addition, a particulate filter is used to remove PM in the exhaust gas. This particulate filter is a filter having a honeycomb structure, for example, and collects PM in exhaust gas and is used while repeating regeneration by burning the accumulated PM at a predetermined timing. When regenerating the particulate filter, an oxidation catalyst is disposed upstream of the particulate filter, and fuel is injected into the exhaust pipe further upstream, so that HC or the like, which is a fuel component, is oxidized by the oxidation catalyst. There is a method of burning the PM deposited on the particulate filter by using the heat generated at the time.

Here, as means for injecting fuel into the exhaust pipe, there is an exhaust purification device using an electromagnetically controlled fuel injection valve used when injecting fuel into the cylinder of the engine. More specifically, as shown in FIG. 9, the NO _X catalyst interposed in an exhaust pipe 404 of the engine, NO _X reducing agent additives provided upstream portion of the exhaust pipe 404 than the NO _X catalyst This is an exhaust emission control device 410 for a diesel engine equipped with an injector 420, and is an exhaust emission purification device using an injector 420 similar to that for fuel injection of the engine as the injector 420 (see Patent Document 1).

There has also been proposed an exhaust purification device using a fuel injection valve different from an injector for fuel injection of an engine. More specifically, as shown in FIGS. 10A to 10B, an exhaust purification device 491 in which a control valve 491b and a nozzle 491a are connected via a connection pipe 491c, An exhaust emission control device using a swirl nozzle 491a that includes a nozzle body 481, a nozzle piece 483, a spring 483c, and a check ball 483b and in which fuel is injected while generating a swirling flow is disclosed (Patent Document). 2).
JP-A-9-96212 (paragraph [0022] FIGS. 1 and 2) JP 2000-240436 A (paragraphs [0027] to [0030] FIGS. 1 to 3)

However, the electromagnetic control valve used in the exhaust emission control device disclosed in Patent Document 1 has a structure in which the nozzle needle is reciprocated inside to seat the injection hole inside, in other words, the injection hole of the nozzle needle. Since the valve structure is opened and closed inside, the fuel injection valve becomes hot due to the exhaust heat and the fuel burns in the injection hole portion, which may cause clogging.
Further, the swirl nozzle used in the exhaust gas purification device disclosed in Patent Document 2 is located at a position where the seat surface of the check ball is deeper than the tip of the nozzle, and the exhaust gas may enter the inside of the nozzle. Therefore, foreign matter such as exhaust heat and soot enters the nozzle, and there is a risk of nozzle burning due to exhaust heat, destabilization of injection characteristics due to the accumulation of foreign matter, and clogging of injection holes.

In view of this, the inventors of the present invention diligently tried to open and close the opening of the injection hole of the fuel injection valve in an exhaust purification device of an internal combustion engine provided with a fuel injection device that injects fuel into the exhaust pipe, It has been found that such a problem can be solved by arranging the seat portion so as to face the exhaust pipe, and the present invention has been completed.
That is, an object of the present invention is to provide an exhaust emission control device for an internal combustion engine that can prevent foreign matter such as soot and exhaust heat from entering the fuel injection valve and prevent the fuel injection valve from being burned out and destabilizing the fuel injection. It is to be.

  According to the present invention, an exhaust purification member disposed in an exhaust pipe of an internal combustion engine for purifying exhaust gas discharged from the internal combustion engine, and a fuel for injecting fuel into the exhaust pipe upstream of the exhaust purification member An exhaust purification device for an internal combustion engine comprising an injection device, wherein the fuel injection device includes a fuel injection valve that injects fuel into the exhaust pipe, and the fuel injection valve has a flange portion on one end side. A valve body having a spring receiving portion on the other end side, a valve seat portion having a seat surface on which the flange portion of the valve body is seated on the fuel injection direction side, a spring receiving portion and a valve seat portion, A spring that biases the body in the valve closing direction, and the seat surface of the valve seat portion is disposed at the tip portion of the fuel injection valve, and the valve seat portion faces the exhaust pipe. Exhaust purification equipment There is provided, it is possible to solve the problems described above.

  In configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the seat surface is substantially coincident with the inner peripheral surface of the exhaust pipe.

  Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the exhaust pipe has a bent portion and the fuel injection valve is disposed in the bent portion.

  Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, the metering unit for adjusting the fuel injection amount injected from the fuel injection valve is connected to the fuel injection valve via the fuel pipe, and the metering unit Is preferably arranged apart from the exhaust pipe.

  In configuring the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the fuel injection valve is fixed to the exhaust pipe, and is installed in an insertion hole of a cooling member having a cooling water circulation path. It is preferable that a gas seal part is comprised by the contact part of at least one part of a surface and at least one part of the internal peripheral surface of the insertion hole of a cooling member.

According to the exhaust gas purification apparatus for an internal combustion engine of the present invention, by configuring the fuel injection hole in the fuel injection valve as an open valve structure, it is possible to make it difficult for heat of exhaust gas and foreign matter to enter the fuel injection valve. At the same time, even if foreign matter such as soot is likely to accumulate in the injection hole, it can be blown off by the momentum of fuel injection and removed by self-cleaning action. In addition, by disposing the seat surface of the valve body at the tip of the fuel injection valve and facing the inside of the exhaust pipe, a region where exhaust gas stays is not formed outside the seat surface position of the fuel injection valve. It can be constituted as follows. Therefore, it is possible to prevent the fuel injection valve from being burned out, to prevent the injection characteristics from becoming unstable due to the accumulation of foreign matters, and to improve the reliability of the exhaust emission control device.
Further, since the injection valve has a predetermined structure, the fuel can be sprayed in a hollow umbrella shape, and the effect that the fuel can be uniformly dispersed and mixed in the exhaust pipe can be obtained.

  Further, in the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the tip of the fuel injection valve directly heats the exhaust gas by arranging the seat surface of the valve body so as to substantially coincide with the inner peripheral surface of the exhaust pipe. However, it is possible to make it difficult for the heat and foreign matter of the exhaust gas to enter the fuel injection valve.

  Further, in the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the fuel injection valve is disposed in the bent portion of the exhaust pipe, so that the fuel injection in the traveling direction of the exhaust gas can be performed, and the exhaust gas can be uniformly distributed in the exhaust gas. It becomes easy to disperse and mix.

  Further, in the exhaust gas purification apparatus for an internal combustion engine of the present invention, by connecting the metering portion of the fuel injection amount to the injection portion via the connection pipe, and disposing the metering portion away from the exhaust pipe, The electromagnetic control part that is relatively weak against heat can be made less susceptible to the exhaust heat. Therefore, the reliability of the exhaust emission control device can be further improved.

  Further, in the exhaust gas purification apparatus for an internal combustion engine according to the present invention, by providing a predetermined seal structure, it is not necessary to use a member that is easily deteriorated by heat, such as an O-ring, and the exhaust gas seal is made less susceptible to the influence of exhaust heat. Can be improved.

  DESCRIPTION OF EMBODIMENTS Embodiments relating to an exhaust gas purification apparatus for an internal combustion engine according to the present invention will be specifically described below with reference to the drawings. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

An embodiment of the present invention is arranged in an exhaust pipe of an internal combustion engine, an exhaust purification member for purifying exhaust gas exhausted from the internal combustion engine, and fuel injection into the exhaust pipe upstream of the exhaust purification member And an internal combustion engine exhaust gas purification device.
In such an exhaust purification device, the fuel injection device includes a fuel injection valve that injects fuel into the exhaust passage, and the fuel injection valve has a flange portion on one end side and a spring receiving portion on the other end side. Body, a valve seat having a seat surface on which the flange portion of the valve body is seated on the fuel injection direction side, and a spring sandwiched between the spring receiving portion and the valve seat portion, and biasing the valve body in the valve closing direction And the seat surface of the valve seat portion is disposed at the tip portion of the fuel injection valve, and the valve seat portion faces the exhaust pipe.
Hereinafter, the configuration of the exhaust emission control device according to the present embodiment will be specifically described with reference to FIGS.

1. FIG. 1 shows an exhaust gas purification apparatus according to this embodiment. In the exhaust purification apparatus 1 shown in FIG. 1, the internal combustion engine 5 for discharging the exhaust gas G, and a diesel engine or a gasoline engine is typically been purified of the NO _X and PM is a problem at present diesel It is more appropriate to target the engine. Further, the exhaust purification device 1 of the present embodiment includes an internal combustion engine operating state detection means 7 for detecting the rotational speed of the internal combustion engine 5, the fuel injection amount, the fuel injection timing, and the like, taking the detection result into consideration. The NO _x concentration and the PM amount can be estimated, and the fuel injection amount into the exhaust pipe can be controlled.

The exhaust pipe 11 is connected to an exhaust gas exhaust port of the internal combustion engine 5, and an exhaust purification member 13 for purifying the exhaust gas is disposed in the middle of the exhaust pipe 11. The cross-sectional shape of the exhaust pipe 11 is not particularly limited, such as a circular, elliptical, or prismatic exhaust pipe, but preferably has a bent portion 14 in the middle thereof. By having such a bent portion 14, a fuel injection device 20 described later can be attached to the bent portion 14 and fuel can be injected in the traveling direction of the exhaust gas. Therefore, it is possible to prevent the injected fuel from adhering to the exhaust pipe 11 and to facilitate the uniform dispersion of the fuel in the exhaust gas.
However, the arrangement position of the fuel injection device 20 is not limited to the bent portion 14.

2. Exhaust purifying member exhaust purification member 13, NO _X catalyst and the particulate filter are typical.
The NO _x catalyst used in the exhaust purification apparatus of the present invention is a catalyst for reducing and purifying NO _x contained in exhaust gas by using the fuel supplied by the fuel injection device 30 as a reducing agent. The NO _x catalyst that can be used is not particularly limited, and known ones such as strontium or barium as an active component on a porous support, alkaline earth metals such as magnesium, and rare earths such as cerium and lanthanum. Metals, those containing noble metals such as platinum and rhodium can be used.

  The particulate filter is a filter member for collecting PM in the exhaust gas passing through the filter and purifying the exhaust gas. When the exhaust purification member is a particulate filter, an oxidation catalyst used for regeneration of the particulate filter is disposed upstream of the particulate filter. The particulate filter is not particularly limited, and a known filter can be used.

3. Fuel Injection Device (1) Overall Configuration The fuel injection device 20 is a device for injecting fuel into the exhaust pipe 11 on the upstream side of the exhaust purification member 13.
An example of the fuel injection device 20 provided in the exhaust purification device 1 of the present embodiment is shown in FIG. The fuel injection device 20 includes a fuel supply unit 30, an injected fuel metering unit 40, and a fuel injection unit 50.
The fuel supply unit 30 includes a fuel tank 31, a feed pump 33 that pumps up the fuel in the fuel tank 31 and pumps it, and a pressure regulating valve 35 that adjusts the fuel pressure to be pumped.
The injected fuel metering unit 40 is disposed on the upstream side and downstream side of the metering valve 41, and the metering valve 41 that meteres the fuel pumped from the fuel supply unit 30 and transfers it to the fuel injection unit 50. Pressure sensors 43 and 45, and a fuel cutoff valve 47 disposed upstream of the metering valve 41.
Further, the fuel injection unit 50 includes a fuel injection valve 51 for injecting the fuel transferred from the injected fuel metering unit 40 into the exhaust pipe, and a cooling member 53 for protecting the fuel injection valve 51 from the exhaust heat. Cooling adapter 53A.

  The fuel supply unit 30, the injected fuel metering unit 40, and the fuel injection unit 50 are connected via a connection pipe (fuel pipe) 21 as a fuel flow path. The connection pipe 21 can be a rubber hose or a metal hose. However, when a metal hose is used, if the injected fuel metering unit 40 and the fuel injection unit 50 are separately arranged on the engine side and the vehicle body side, the phase and displacement difference during vibration differ. Since the hose may be damaged, the injected fuel metering unit 40 and the fuel injection unit 50 are preferably arranged on the same side of the engine side or the vehicle body side, respectively.

(2) Fuel supply unit The fuel tank 31 in the fuel supply unit 30 can be a dedicated tank for storing the fuel injected into the exhaust pipe, but it can save space without increasing the number of parts. For this reason, it is preferable to also use the fuel tank for combustion of the internal combustion engine.
The feed pump 33 is not particularly limited, and a mechanical pump or an electric pump can be used. In particular, when an electric pump is used, if a dangerous state such as fuel leakage occurs, the pumping can be stopped immediately at the uppermost stream of a series of fuel flow paths, so safety can be improved, while a mechanical pump can be used. When used, energy consumption during operation can be reduced.
Furthermore, the pressure regulating valve 35 can be configured using, for example, a valve having a check valve structure. With such a pressure regulating valve, when the pressure in the fuel flow path exceeds a predetermined value, the valve is opened and a part of the fuel is returned to the fuel tank, so that the pressure of the fuel to be pumped is maintained at the predetermined value. be able to.

  Although not shown, the fuel supply unit for supplying the fuel to be injected into the exhaust pipe uses a surplus fuel recirculated from the low pressure system in the high pressure pump for supplying the high pressure fuel into the cylinder of the internal combustion engine. It can also be. In such a configuration, in order to prevent the fuel supply from the high-pressure pump from being continuously performed in the event of an abnormality such as a fuel leak, a combustion supply cutoff such as a fuel cutoff valve of an injected fuel metering unit, which will be described later, is provided. Preferably means are provided.

(3) Injection fuel metering unit As the metering valve 41 in the injected fuel metering unit 40, for example, an electromagnetic ON / OFF valve can be used. This electromagnetic ON / OFF valve, NO _X amount and the reduction in the NO _X catalyst, based on the fuel injection amount that is required in accordance with the amount of PM deposited in the particulate filter, controls the energization time for opening and closing the valve (PWM control) and the fuel flow rate can be controlled.
However, in addition to such an electromagnetic ON / OFF valve, any other valve or a valve other than the valve may be used as long as the fuel flow rate can be adjusted.

  Here, it is preferable that the injected fuel metering unit 40 is connected to the fuel injection unit 50 via the connection pipe 21, and the injected fuel metering unit 40 is disposed away from the exhaust pipe. By arranging in this way, it is possible to suppress the influence of exhaust heat on the metering unit that performs fuel metering such as an electromagnetic ON / OFF valve. Therefore, the metering unit can be prevented from burning and fuel injection can be performed stably, so that the reliability of the exhaust emission control device can be improved.

The pressure sensors 43 and 45 are arranged to detect the fuel pressure on the upstream side and the downstream side of the metering valve 41. Based on the pressure values detected by the pressure sensors 43 and 45, for example, the presence or absence of fuel leakage is monitored, or the injection characteristic is improved by correcting the pressure value by the pressure regulating valve described above. Can do.
In addition, the fuel shut-off valve 47 shuts off the fuel supply to reduce the amount of fuel leak when, for example, the pressure value detected by the pressure sensors 43 and 45 decreases and the risk of fuel leakage is detected. Provided to prevent or catch fire. However, as described above, when an electric pump is used as the feed pump, the fuel supply can be cut off by stopping the supply of power, so that the fuel cut-off valve can be omitted.

(4) Fuel injection part The fuel injection part in the exhaust gas purification apparatus of this embodiment is shown in FIG.3 and FIG.4. FIG. 3A shows a state in which the fuel injection unit 50 is attached to the exhaust pipe 11, and FIG. 3B is a cross-sectional view thereof. FIG. 4 is a view showing the fuel injection unit 50 separately for each member.
In the fuel injection unit 50 shown in FIGS. 3 and 4, a fuel injection valve 51 for injecting the fuel transferred from the injected fuel metering unit into the exhaust pipe is attached to a cooling adapter 53 </ b> A as a cooling member 53. In addition, the cooling adapter 53A is attached to the exhaust pipe 11 and fixed. The fuel injection valve 51 and a cooling adapter 53A as a cooling member are fixed in contact with each other at a screw surface 59.
In addition, a heat shield cover (cover member) 55 is provided between the cooling adapter 53A and the exhaust pipe 11 to make it difficult for the exhaust heat to reach the cooling adapter 53A and the fuel injection valve 51. Furthermore, low heat transfer gaskets 57A and 57B are provided to prevent the heat of the exhaust pipe 11 from being directly transmitted to the cooling adapter 53A so as to sandwich the heat shield cover 55 from both sides.

Here, in the fuel injection device used in the present embodiment, the fuel injection valve 51 has a mechanical valve structure that does not include an electromagnetic control unit. Specifically, as shown in FIG. 5, the fuel injection valve 51 includes a valve body 71 having a flange portion 71 a on one end side and a spring receiving portion 71 b on the other end side, and a flange portion 71 a of the valve body 71. A valve seat 73 having a seat surface 73a on the fuel injection direction side, and a spring 75 sandwiched between the spring receiving portion 71b and the valve seat portion 73 and biasing the valve body 71 in the valve closing direction. The structure does not include an electromagnetic control unit.
With such a mechanical valve structure, the constituent member can be formed using a material having high heat resistance, and high durability against exhaust heat can be exhibited. On the other hand, since the injection fuel metering section that is relatively weak against heat can be arranged away from the exhaust pipe, it is possible to prevent the metering section from being burned out and to prevent malfunction due to thermal deformation or the like. .
In the fuel injection valve 51 shown in FIG. 5, a spring seat 77 is fixed to the valve body 71 as the spring receiving portion 71 b of the valve body 71.

Further, in the present invention, the seat surface 73 a of the valve seat portion 73 of the fuel injection valve 51 is disposed at the distal end portion of the fuel injection valve 51, and the valve seat portion 73 is disposed so as to face the exhaust pipe 11. ing. Since the seat surface 73 a of the fuel injection valve 51 is disposed at the tip of the fuel injection valve 51, it is possible to prevent the exhaust gas from entering the fuel injection valve 51. Further, since the seat surface 73a is disposed so as to face the exhaust pipe 11, the exhaust gas is less likely to stay in the vicinity of the injection hole of the fuel injection valve 51, and the heat and foreign matter of the exhaust gas are removed from the fuel. It can be made difficult to enter the injection valve 51.
In particular, when the seat surface 73a located at the tip of the fuel injection valve 51 is disposed so as to substantially coincide with the inner peripheral surface of the exhaust pipe 11, it is possible to prevent exhaust heat and foreign matter from entering as described above. In addition, the fuel injection valve 51 can be prevented from being heated by the exhaust heat. Accordingly, it is possible to prevent the constituent members of the fuel injection valve 51 from being deformed by exhaust heat, and to prevent the fuel from deteriorating or carbonizing inside the fuel injection valve 51, and to prevent the injection hole from being formed by foreign matter contained in the exhaust gas. Can prevent clogging.

  Further, since the fuel injection valve 51 has a predetermined structure including a so-called outwardly opening valve body 71 with respect to the fuel inflow side, the exhaust gas is shut off outside the fuel injection valve 51, and the exhaust gas is discharged. Can be prevented from entering the inside of the fuel injection valve 51, particularly even the injection hole portion. Furthermore, even if foreign matter such as soot is likely to accumulate in the injection hole, it can be blown off by the momentum of fuel injection and removed by self-cleaning action.

Furthermore, since the fuel injection valve 51 has an open valve structure, the fuel is injected in a hollow umbrella shape, so that the area where the fuel comes into contact with air or exhaust gas is increased, and fuel atomization is promoted. can do. Therefore, the fuel can be uniformly dispersed and mixed with the exhaust gas, so that the fuel is less likely to adhere to the exhaust pipe and can be made to uniformly flow into the exhaust purification member. Therefore, it is possible to improve exhaust gas purification efficiency while preventing deterioration of fuel consumption.
In particular, as shown in FIGS. 6A to 6C, the fuel is injected when the lift is voluntarily changed without limiting the maximum lift amount of the valve body 71 in the fuel injection valve 51. In this case, a chattering effect in which the valve body 71 vibrates finely by the fuel injection pressure and the urging force of the spring 75 can be obtained. Therefore, the oil film thickness of the injected fuel 80 varies, and the atomization of the fuel 80 can be further promoted. Therefore, it becomes easier to disperse more uniformly in the exhaust gas, and exhaust purification efficiency and the like can be further improved.

As illustrated in FIGS. 7 and 8, the cooling adapter 53A to which the fuel injection valve 51 is attached includes an insertion hole 53a to which the fuel injection valve is attached, and a donut shape formed outside the insertion hole 53a. The gap portion 53b communicates with the gap portion 53b and is formed along the insertion hole 53a. One end of the gap portion 53b communicates with the cooling water passage 53d and the gap portion 53b. And a cooling water passage 53f constituting one end of the cooling water drain 53e, and a bolt hole 53g into which a bolt for attaching to the exhaust pipe is inserted.
7A is a perspective view of the cooling adapter 53A viewed from the side where the cooling adapter 53A is attached to the exhaust pipe, and FIG. 7B is a perspective view of the cooling adapter 53A viewed from the fuel injection valve insertion side. is there. FIG. 8A is a side view of the cooling adapter 53A viewed from the side where the cooling water supply port and the discharge port exist, and FIG. 8B shows the cooling adapter 53A of FIG. FIG. 8C is a cross-sectional view taken along the axis of the insertion hole of the fuel injection valve, and FIG. 8C is a cross-sectional view of the AA cross section in FIG. These are sectional views which looked at the BB section in Drawing 8 (a) in the direction of an arrow.

In this cooling adapter 53A, the cooling water passages 53d and 53f and the doughnut-shaped gap 53b form a cooling water circulation path, and the cooling water introduced from the water supply port 53c passes through the cooling water passage 53d and becomes a donut shape. And then passes through the cooling water passage 53f and is discharged from the drain port 53e. At this time, since each of the cooling water passages 53d and 53f and the doughnut-shaped gap 53b are close to the insertion hole 53a in which the fuel injection valve is mounted, the efficiency of the fuel injection valve is improved when the cooling water passes. Can be cooled automatically.
The cooling water circulating in the cooling adapter may be used together with radiator water, or dedicated cooling water may be used.

  With such a cooling adapter 53A, since it is made of a member different from the exhaust pipe, it is less affected by the exhaust heat, and compared with the case where a cooling water passage is provided on the exhaust pipe side, The cooling efficiency of the fuel injection valve can be significantly improved. In addition, since the cooling adapter 53A is damaged due to being made of a member different from the exhaust pipe, only the cooling adapter 53A can be replaced, which reduces workability and maintenance costs. In terms of maintenance, it has excellent maintainability associated with long-term use.

  Further, the cooling adapter 53A is configured using a metal having high heat conductivity such as iron or chromium / molybdenum alloy in order to increase the cooling efficiency, and in particular, efficiently dissipates the heat of the fuel injection valve to the cooling water. be able to. In order to prevent looseness due to thermal expansion between the fuel injection valve and the cooling adapter, it is preferable to use a metal equivalent to the constituent material of the fuel injection valve in order to match the linear expansion coefficients.

3 and FIG. 4, the heat shield cover 55 provided between the cooling adapter 53 </ b> A and the exhaust pipe 11 is located between the cooling adapter 53 </ b> A and the exhaust pipe 11 in the vicinity of the tip of the fuel injection valve 51. It is a member used to form a gap S between them. By forming the gap S, the exhaust heat hardly reaches the cooling adapter 53A or the fuel injection valve 51. Therefore, it can prevent that the cooling efficiency by cooling water falls.
The heat shield cover 55 has a recess 55a having a predetermined depth for forming a gap, an opening 55b for allowing the tip of the fuel injection valve 51 to be in the exhaust pipe, and a bolt for attaching the exhaust pipe. Bolt holes 55c into which 69 are inserted are provided.
Further, regarding the constituent material of the heat shield cover 55, as in the present embodiment, a low heat transfer gasket 57A between the heat shield cover 55 and the exhaust pipe 11 and between the heat shield cover 55 and the cooling adapter 53A, When 57B is provided, the constituent material of the heat shield cover 55 is not particularly limited. However, when heat shielding measures such as the gaskets 57A and 57B are not taken, it is preferable to use a low heat transfer material such as ceramic.

Further, the low heat transfer gaskets 57A and 57B interposed between the heat shield cover 55 and the cooling adapter 53A and between the heat shield cover 55 and the exhaust pipe 11, respectively, allow the heat of the exhaust pipe 11 to be directly It is a member for preventing transmission to the cooling adapter 53A. By interposing such a low heat transfer gasket, it is possible to prevent the cooling efficiency by cooling water from being lowered.
As shown in FIG. 4, in this low heat transfer gasket, openings 57Aa and 57Ba having a size substantially equal to the outer periphery of the recess 55a provided in the heat shield cover 55 and bolts 69 for attaching the exhaust pipe are inserted. Bolt holes 57Ab and 57Bb are provided. In addition, this gasket is formed using a ceramic material or metal beads in order to keep the heat conductivity of the gasket low.
The “low heat transfer gasket” means a gasket having a thermal conductivity lower than that of at least the cooling member. For example, a ceramic material or metal beads may be used on the cooling member made of iron. Applicable gaskets are used.

Further, as shown in FIG. 3B, the cooling adapter 53A includes a convex portion 54 fitted into the exhaust pipe 11, and the tip of the fuel injection valve 51 is located in the vicinity of the tip of the convex portion 54, so that the fuel injection With the portion 50 attached to the exhaust pipe 11, the position of the tip of the fuel injection valve 51 is substantially matched with the inner peripheral surface of the exhaust pipe 11. That is, in FIG. 3B, the height of the convex portion 54 of the cooling adapter 53A and the depth of the concave portion 55a of the heat shield cover 55 that covers the convex portion 54 are substantially equal to the thickness of the wall surface of the exhaust pipe 11. Are attached so that the tip position of the fuel injection valve 51 coincides with the inner peripheral surface of the exhaust pipe 11.
Therefore, as described above, while the tip of the fuel injection valve is not exposed to the exhaust gas, the exhaust gas does not stay near the tip of the fuel injection valve, and the tip of the fuel injection valve is affected by the exhaust heat. Can be difficult.

  Further, in the fuel injection part 50 shown in FIGS. 3B and 4, the fuel injection valve 51 has a large diameter part 52 a and a small diameter part 52 b in the part inserted into the insertion hole of the cooling adapter 53 </ b> A. A step 65 is provided on the outer peripheral surface, and the cooling adapter 53 </ b> A has a seat portion 67 that contacts the step 65 of the fuel injection valve 51. The stepped portion 65 and the seat portion 67 are seated to form a seal portion, and the exhaust gas can be prevented from leaking from the gap between the fuel injection valve and the cooling adapter. In such a seal portion, since the exhaust gas seal portion can be configured without using a relatively heat-sensitive seal member such as an O-ring, the cooling adapter 53A and the fuel injection valve 51 are exposed to a high temperature. Even so, it is possible to prevent the exhaust gas from leaking out.

  Further, screw grooves 61 and 63 are formed on the outer peripheral surface of the portion of the fuel injection valve 51 to be inserted into the cooling adapter 53A and the inner peripheral surface of the insertion hole 53a in which the fuel injection valve of the cooling adapter 53A is inserted. The screw surfaces 59 are in contact with each other and fixed. Therefore, since the contact area between the fuel injection valve and the cooling adapter is increased, the cooling efficiency by the cooling water is remarkably enhanced.

Moreover, as shown in FIG.3 (b), it is preferable to form the cooling water supply port 53c in the cooling adapter 53A in the front end side of the fuel injection valve 51 rather than the drainage port 53e. By arranging in this way, it is possible to cool the tip portion of the fuel injection valve that is easily affected by the exhaust heat before the cooling water is warmed. That is, since the above-mentioned valve body, the valve seat part, and the spring are disposed at the tip portion of the fuel injection valve, the tip portion can be intensively cooled. Therefore, burnout of the fuel injection valve can be prevented, and it is possible to more effectively prevent the fuel from being seized in the vicinity of the injection hole and making the injection characteristics unstable.
In the cooling adapter of FIG. 3, the water supply port and the drain port are arranged on the same surface side, but it is not limited to such a configuration, and may be arranged on the opposite surface side, A plurality of water supply ports or drain ports can be provided on an arbitrary surface.

  As described above, in the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the fuel injection valve having an outwardly opening valve structure is used as the fuel injection valve, and the seat surface faces the tip of the fuel injection valve and the exhaust pipe. This arrangement can prevent the exhaust gas from entering the fuel injection valve. Therefore, it is possible to prevent the fuel injection valve from being affected by the exhaust heat and foreign matter in the exhaust gas from accumulating inside the valve. Therefore, fuel injection can be performed stably, and the reliability of the exhaust emission control device can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram provided for explaining the overall configuration of an exhaust emission control device for an internal combustion engine according to an embodiment of the present invention. It is a figure which shows the structural example of the fuel-injection apparatus used for embodiment of this invention. It is a figure provided in order to demonstrate the structural example of the fuel-injection part of a fuel-injection apparatus. It is a figure provided in order to demonstrate the component of a fuel-injection part. It is a figure which shows the structural example of a mechanical fuel injection valve. It is a figure provided in order to demonstrate the chattering effect of a valve body. It is a perspective view provided in order to demonstrate the structural example of the cooling adapter as a cooling member. It is the side view and sectional drawing which are provided in order to demonstrate the structural example of the cooling adapter as a cooling member. It is a figure provided in order to demonstrate the structure of the conventional exhaust gas purification apparatus. It is a figure provided in order to demonstrate the structure of another conventional exhaust gas purification apparatus.

Explanation of symbols

1: exhaust purification device, 5: internal combustion engine, 7: operating state detection means, 11: exhaust pipe, 13: exhaust purification member, 20: fuel injection device, 21: connection pipe, 30: fuel supply unit, 31: fuel tank 33: feed pump, 35: pressure regulating valve, 40: injected fuel metering unit, 41: metering valve, 43/45: pressure sensor, 47: fuel shutoff valve, 50: fuel injector, 51: fuel injector, 52a: large diameter portion, 52b: small diameter portion, 53: cooling member, 53A: cooling adapter, 54: convex portion, 55: heat shield cover (cover member), 55a: concave portion, 55b: opening portion, 55c: bolt hole, 57A / 57B: low heat transfer gasket, 57Aa / 57Ba: opening, 57Ab / 57Bb: bolt hole, 59: screw surface, 61/63: screw groove, 65: step, 67: sheet part, 69: bolt, 71: Valve body, 71 : Flange portion, 71b: spring receiving portion, 73: valve seat portion, 73a: seat surface, 75: spring

Claims (5)

An exhaust purification member disposed within an exhaust pipe of the internal combustion engine for purifying exhaust gas discharged from the internal combustion engine; and a fuel injection device for injecting fuel into the exhaust pipe upstream of the exhaust purification member; In an exhaust gas purification apparatus for an internal combustion engine,
The fuel injection device includes a fuel injection valve that injects the fuel into the exhaust pipe,
The fuel injection valve includes a valve body having a flange portion on one end side and a spring receiving portion on the other end side, and a valve seat having a seat surface on which the flange portion of the valve body is seated on the fuel injection direction side. And a spring that is sandwiched between the spring receiving portion and the valve seat portion and biases the valve body in a valve closing direction,
An exhaust purification device for an internal combustion engine, wherein a seat surface of the valve seat portion is disposed at a tip portion of the fuel injection valve, and the valve seat portion faces the exhaust pipe.   2. The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the seat surface substantially coincides with an inner peripheral surface of the exhaust pipe.   The exhaust emission control device for an internal combustion engine according to claim 1 or 2, wherein the exhaust pipe has a bent portion, and the fuel injection valve is disposed in the bent portion.   A metering unit for adjusting the fuel injection amount injected from the fuel injection valve is connected to the fuel injection valve via a fuel pipe, and the metering unit is disposed apart from the exhaust pipe. The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 3, wherein the exhaust gas purification device is an internal combustion engine.   The fuel injection valve is fixed to the exhaust pipe and attached to an insertion hole of a cooling member having a cooling water circulation path, and at least a part of an outer peripheral surface of the fuel injection valve and the insertion of the cooling member The exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 4, wherein the gas seal portion is configured by a contact portion with at least a part of the inner peripheral surface of the hole.

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