JP2002256850A - Fuel adding device to catalyst device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel adding device to a catalyst device capable of accurately metering and atomizing the supplying fuel as well as being equipped with safety. SOLUTION: The fuel adding device to a catalyst device for adding the fuel for reduction to a catalyst device 2 equipped with an exhaust pipe 1 of a diesel engine comprises a venturi 3 provided in the exhaust pipe 1 on the upstream side of the catalyst device 2, a pump 5 provided in a fuel tank 4, a fuel meter 6 metering the fuel discharged from the pump 5 provided in the fuel tank 4 and supplying into the venture 3, and a controller 10 controlling the pump 5 and the fuel meter 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel adding device for supplying a reducing fuel to a NOx reducing catalyst mounted on an exhaust pipe of a diesel engine.

[0002]

2. Description of the Related Art In order to reduce nitrogen oxides (NOx) emitted from a diesel engine, a method of supplying a reducing fuel upstream of a NOx reducing catalyst has been studied. In the method of supplying the reducing fuel to the catalyst device mounted on the exhaust pipe, it is important that the amount of the supplied fuel can be accurately adjusted and the fuel can be atomized. Further, since the number of fuel pipes arranged under the floor of the vehicle to supply fuel to the catalyst device increases, a configuration in which the fuel pipes can be shortened and the fuel pressure can be reduced is desirable from the viewpoint of ensuring safety.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel adding apparatus for a catalyst device, which can accurately meter and atomize a supplied fuel and has safety. An object of the invention described in claim 1 is to provide a fuel addition device that can supply atomized fuel to a catalyst device with a simple configuration. An object of the present invention described in claim 2 is to provide a fuel adding device according to claim 1 in which the pressure of a fuel pipe from a fuel tank to a venturi can be reduced to improve safety.

The object of the invention described in claim 3 is that of claim 2
The present invention is to provide a fuel adding device provided with a fuel meter which can accurately meter the amount of fuel supplied with a simple configuration. An object of the invention described in claim 4 is to provide a fuel addition device according to claim 2, which can reduce the discharge pressure of a fuel supply pump and can improve safety.

A fifth object of the present invention is to directly attach a pressurized meter to an exhaust pipe, thereby simplifying fuel piping and effectively utilizing a fuel injection pressure of the pressurized meter. To provide an addition device. An object of the present invention described in claim 6 is to provide a fuel adding apparatus having a fuel metering device according to claim 5, which can accurately measure the amount of fuel to be supplied.

The object of the invention described in claim 7 is that of claim 5
It is an object of the present invention to provide a fuel adding device which can generate a rapid pressure change with a quick response and is excellent in atomizing the fuel. An object of the present invention described in claim 8 is to provide a fuel adding device capable of reducing the discharge pressure of a fuel supply pump according to any one of claims 5 to 7.

Another object of the present invention is to reduce the size of a device directly attached to an exhaust pipe, to provide an excellent mountability, and to dispose a fuel meter and a fuel supply pump in a fuel tank. It is an object of the present invention to provide a fuel adding device that has improved safety by keeping a supply line out. An object of the present invention described in claim 10 is to provide a fuel adding device having a fuel metering device according to claim 9, which can accurately measure the amount of fuel to be supplied.

An object of the present invention described in claim 11 is to provide a fuel adding apparatus according to claim 9, which has a quick response and can generate a rapid pressure change and is excellent in atomizing fuel. The object of the invention described in claim 12 is that of claims 9 to
It is still another object of the present invention to provide a fuel adding apparatus capable of uniformly adding fuel injected into an exhaust pipe to a catalyst device.

An object of the invention described in claim 13 is to provide a fuel adding apparatus capable of supplying fuel to a catalyst device with a simple configuration by supplying fuel to an exhaust pipe from a return flow path of fuel from a fuel injection pump. On offer. The object of the invention described in claim 14 is to provide a fuel addition device according to claim 13 that can accurately meter fuel supplied to an exhaust pipe with a simple configuration.

An object of the present invention described in claim 15 is to provide a fuel adding apparatus according to claim 13 or claim 14 with a simple configuration and improved safety. An object of the invention described in claim 16 is to provide a fuel addition device according to any one of claims 13 to 15, which can supply high-pressure fuel to an exhaust pipe. An object of the present invention described in claim 17 is to provide a fuel adding apparatus capable of preventing an adverse effect on a fuel injection pump and supplying a proper amount of fuel in any one of claims 13 to 15. It is in.

[0011]

According to a first aspect of the present invention, there is provided a fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, the device being provided upstream of the catalyst device. It comprises a venturi provided in the exhaust pipe, and fuel supply means for supplying fuel in a fuel tank to the venturi.

According to a second aspect of the present invention, in the first aspect, the fuel supply means is provided with a fuel supply pump provided in the fuel tank and discharged from the fuel supply pump provided in the fuel tank. It comprises a fuel meter for metering fuel and supplying it to the venturi, and a control device for controlling the fuel supply pump and the fuel meter.

According to a third aspect of the present invention, in the second aspect, the fuel meter is an electromagnetic open / close type fuel meter that opens and closes a fuel passage by an electromagnetic valve. Alternatively, the fuel ratio is adjusted by changing the duty ratio.

According to a fourth aspect of the present invention, in the second aspect, the fuel meter has a casing having a pump chamber therein and a piston, and pressurizes the fuel sucked into the pump chamber by energization. It is a solenoid type that sends out, and is characterized by metering at a drive frequency.

According to a fifth aspect of the present invention, there is provided a fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, the fuel supply pump being provided in a fuel tank; And a pressurized metering device mounted on the exhaust pipe upstream of the catalytic device.

According to a sixth aspect of the present invention, in the fifth aspect, the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by an electromagnetic solenoid. In addition, the fuel sucked into the pump chamber is pressurized and discharged, and the discharge amount is adjusted at a drive frequency.

According to a seventh aspect of the present invention, in the fifth aspect, the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element. In addition, the fuel sucked into the pump chamber is pressurized and discharged, and the discharge amount is adjusted by a drive frequency or a conduction voltage.

According to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, the valve opening pressure of the pressurized meter is higher than the discharge pressure of the fuel supply pump. .

According to a ninth aspect of the present invention, there is provided a fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, wherein the fuel supply pump is provided in a fuel tank. A fuel meter provided in a tank for metering and discharging fuel discharged from the fuel supply pump, a fuel supply means including a control device for controlling the fuel supply pump and the fuel meter, and the catalyst A discharge valve that is provided in the exhaust pipe upstream of the device and that jets the fuel supplied from the fuel supply means into the exhaust pipe.

According to a tenth aspect of the present invention, in the ninth aspect, the fuel meter is an electromagnetic switching type fuel meter which opens and closes a fuel passage by an electromagnetic valve, and has a duty ratio for opening and closing a fuel passage. It is characterized by changing and metering.

According to an eleventh aspect of the present invention, in the ninth aspect, the fuel metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element, It is a pressurized metering device that pressurizes and discharges the fuel sucked into the pump chamber and controls the discharge amount with a drive frequency or an energizing voltage.

According to a twelfth aspect of the present invention, in any one of the ninth to eleventh aspects, the discharge valve injects fuel vertically or parallel to an exhaust flow in the exhaust pipe. And

According to a thirteenth aspect of the present invention, there is provided a fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, wherein a return flow of a fuel injection pump mounted on the diesel engine is provided. A branch passage is provided in the passage and a passage shutoff valve is provided downstream of the branch to spray the exhaust pipe upstream of the catalyst device.

According to a fourteenth aspect of the present invention, in the thirteenth aspect, the passage shutoff valve is an electromagnetic valve that shuts off a passage, and adjusts fuel by changing a driving frequency. According to a fifteenth aspect of the present invention, in any one of the thirteenth and fourteenth aspects, the passage shutoff valve is provided in a fuel tank.

The invention according to claim 16 is the invention according to claims 13 to
A check valve according to claim 15, wherein a check valve is provided upstream of the branch of the return flow path. According to a seventeenth aspect of the present invention, in any one of the thirteenth to fifteenth aspects, a pulsation damping device is provided upstream of the branch of the return flow path.

[0026]

According to the first aspect of the present invention, the venturi is provided in the exhaust pipe upstream of the catalyst device, and the fuel in the fuel tank is supplied to the venturi by the fuel supply means. The converted fuel can be supplied to the catalyst device.

According to the second aspect of the present invention, the fuel metering device comprises a fuel supply pump in the fuel tank and a fuel metering device for metering the fuel discharged from the fuel supply pump and supplying the fuel to the venturi. Since the fuel supply pump and the fuel meter are housed in the fuel tank, the pressure of the fuel pipe from the fuel tank to the venturi can be reduced, and safety can be improved.

According to the third aspect of the present invention, the fuel meter is an electromagnetic switching type fuel meter which opens and closes a fuel passage by an electromagnetic valve, and controls a driving frequency or a duty ratio for opening and closing a fuel passage. Since the fuel amount is changed and metered, the fuel amount to be supplied can be accurately metered with a simple configuration.

According to the fourth aspect of the present invention, the fuel meter is a pressurized meter that includes a piston driven by an electromagnetic solenoid and pressurizes and discharges the fuel sucked into the pump chamber. Since the discharge amount is adjusted, the discharge pressure of the fuel supply pump can be reduced, and safety is improved.

According to the fifth aspect of the present invention, since the fuel supply pump provided in the fuel tank and the pressurized meter attached to the exhaust pipe upstream of the catalyst device are provided, the pressurized type meter is provided. By directly attaching the meter to the exhaust pipe, fuel piping is simplified, and the injection pressure of the pressurized meter can be used effectively.

In the invention according to claim 6, the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by an electromagnetic solenoid, and sucked into the pump chamber. Since the fuel is pressurized and discharged and the discharge amount is measured at the drive frequency, the amount of fuel to be supplied can be accurately measured.

[0032] In the invention according to claim 7, the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element.
While pressurizing and discharging the fuel sucked into the pump chamber,
Since the discharge amount is adjusted by the driving frequency or the energizing voltage, the response can be made rapidly and a rapid pressure change can be generated, and the fuel is finely atomized.

According to the eighth aspect of the present invention, since the valve opening pressure of the pressurized meter is set higher than the discharge pressure of the fuel supply pump, the discharge pressure of the fuel supply pump can be reduced. Excellent safety.

According to the ninth aspect of the present invention, a fuel supply pump provided in the fuel tank, a fuel meter provided in the fuel tank for metering and discharging fuel discharged from the fuel supply pump, A fuel supply means comprising a control device for controlling the fuel supply pump and the fuel metering device; and a fuel supply means provided in the exhaust pipe upstream of the catalyst device, for injecting fuel supplied from the fuel supply means into the exhaust pipe. Since it consists of a discharge valve, the equipment directly attached to the exhaust pipe can be reduced in size and excellent in mountability, and a fuel meter and a fuel supply pump are arranged in the fuel tank so that the fuel supply line does not go out. Therefore, the safety is high.

According to the tenth aspect of the present invention, the fuel meter is an electromagnetic switching type fuel meter which opens and closes a fuel passage by an electromagnetic valve, and adjusts the fuel by changing a duty ratio for opening and closing the fuel passage. Therefore, the amount of fuel to be supplied can be accurately measured.

According to the eleventh aspect, the fuel metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element.
While pressurizing and discharging the fuel sucked into the pump chamber,
Since it is a pressurized metering device that adjusts a discharge amount by a driving frequency or an energizing voltage, it has a quick response and can generate a rapid pressure change, and is excellent in atomizing fuel.

According to the twelfth aspect of the present invention, the discharge valve is
Since the fuel is injected perpendicularly or parallel to the exhaust stream line in the exhaust pipe, the fuel injected into the exhaust pipe can be uniformly added to the catalyst device.

According to the thirteenth aspect of the present invention, a branch flow path is provided in the return flow path of the fuel injection pump mounted on the diesel engine, and a passage shutoff valve is provided downstream of the branch, so that the fuel injection pump is provided upstream of the catalyst device. Because it sprays on the exhaust pipe,
Fuel can be supplied to the catalyst device with a simple configuration without separately adding a fuel supply pump.

According to the fourteenth aspect of the present invention, the passage shutoff valve is an electromagnetic valve that shuts off the passage, and the fuel is metered by changing the drive frequency. Can be adjusted.

In the invention according to the fifteenth aspect, since the passage shutoff valve is provided in the fuel tank, safety can be improved with a simple configuration. In the invention according to claim 16, since the check valve is provided upstream of the branch of the return flow path, high-pressure fuel can be supplied to the exhaust pipe.

According to the seventeenth aspect, the pulsation damping device is provided upstream of the branch of the return flow path.
An adverse effect on the fuel injection pump can be prevented, and an appropriate amount of fuel can be supplied.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Invention] FIG. 1 shows a schematic configuration of a fuel adding apparatus A according to claims 1 to 4. A catalyst device 2 for reducing NOx and purifying exhaust gas is mounted on an exhaust pipe 1 of a diesel engine. A fuel addition device A according to the present invention includes a venturi 3 installed in an exhaust pipe 1 on the upstream side of a catalyst device 2 and a fuel tank 4 provided in the venturi 3.
A pump 5 for supplying fuel from the pump 5, a fuel meter 6 for metering the fuel discharged from the pump 5, and a control device 10 for controlling the pump 5 and the meter 6 are provided.

FIG. 2 shows a meter 6 according to the first embodiment. The metering device 6 is an electromagnetic valve, and has a fuel inlet 6 at one end.
1. A structure in which a valve body 65 urged in a valve closing direction by a return spring 64 and an electromagnetic coil 66 for attracting the valve body 65 in a valve opening direction are provided in a casing 63 having a discharge port 62 at the other end. . When the electromagnetic coil 66 is energized, the valve body 65 is sucked to open the discharge port 62, and when the energization is stopped, the discharge port 62 is closed by the spring 64.

The operation of the first embodiment will be described. The pump 5 is driven under appropriate conditions controlled based on a command from the control device 10 during operation of the engine, and fuel is supplied from the high-pressure pipe 11 to the meter 6. The on-off control of the meter 6 is performed so that the fuel amount matches the operating condition of the engine.
The discharge port 62 is opened and closed by the valve body 65. The opening time of the discharge port 62 is controlled by changing the duty ratio at a constant drive frequency, for example, and the fuel for reduction is supplied to the venturi 3 in the exhaust pipe 1.

The metered fuel is delivered from the discharge port 62 to the low pressure pipe 12 and reaches the venturi 3. Since the delivered fuel is not atomized by itself, Venturi 3
The NOx reduction catalyst in the catalyst device 2 uniformly adheres to the surface of the carrier on which the NOx reducing catalyst is
Is reduced.

FIG. 3 shows a fuel pressure metering type meter 7 according to another embodiment. The metering device 7 is of a pressurized delivery type, and includes a casing 73 having a suction port 71 and a discharge port 72,
A pump chamber 74 is provided. In the pump chamber 74, a return spring 75 and a piston 76 urged in the valve opening direction by the return spring 75 are slidably accommodated. An armature 77 is integrally connected to the piston 76 via a rod, and an electromagnetic coil 78 that attracts the armature 77 in the valve opening direction is mounted on the casing 73. The suction port 71 and the discharge port 72 are provided with a suction valve 7a and a discharge valve 7b, which are check valves.

The pump chamber 74 is connected to the pump chamber 74 via the suction valve 7a.
Fuel from the pump 5 is supplied. The suction valve 7a is set to a valve opening pressure equal to or higher than the cutoff pressure of the pump 5. The valve opening pressure of the discharge valve 7b does not need to have substantially, and only needs to have a check effect. The fuel supplied to the pump chamber 74 of the meter 7 is
When the coil 78 is energized, the armature 77 is attracted and moves rightward in the drawing, and the piston 76 pressurizes the fuel in the pump chamber 74. When the pressure in the pump chamber 74 increases and becomes equal to or higher than the valve opening pressure (for example, 5 kg / cm ² ) of the discharge valve 7b, the pump chamber 74 is sent out from the discharge port 72 to the low-pressure pipe 12. This embodiment has an advantage that the pumping capacity of the pump 5 can be greatly reduced.

[Second Invention] FIG. 4 shows a fuel adding apparatus B according to one embodiment of the second invention. In this embodiment, a pressurized delivery type meter 7 for injecting fuel into the exhaust pipe 1 upstream of the catalyst device 2 is directly installed in the exhaust pipe 1. The pressurized delivery type metering device 7 is an electromagnetic valve type pressurizing pump, and when the coil 78 is energized, the armature 77 is sucked in the valve opening direction (downward in the figure) to push down the piston 76 and the pump chamber 74.
Pressurized fuel.

When the fuel in the pump chamber 74 becomes equal to or higher than a predetermined pressure, the discharge valve 7b is opened, and the atomized fuel is injected into the exhaust pipe 1. In the pump chamber 74, fuel is supplied from the pump 5 installed in the fuel tank 4 through the high-pressure pipe 11 via the suction valve 7a. The discharge valve 7b includes a ball valve body 12a and a spring 12b, and performs injection at a set valve opening pressure or higher.

FIG. 5 shows a pressurized delivery type meter 7A according to a second embodiment of the second invention, comprising an armature 77 and a coil 78.
Instead of the driving mechanism described above, a piezoelectric laminate 79 for driving the piston 76 in the casing 73 is provided. When the piezoelectric laminate 79 is energized, it expands and pushes down the piston 76 to pressurize the fuel in the pump chamber 74. When the fuel pressure becomes equal to or higher than a predetermined pressure, the discharge valve 7b is opened and the fuel is injected into the exhaust pipe 1.

The pressure delivery type meter 7A can change the amount of extension of the piezoelectric laminate 79 by the applied voltage, and can perform metering in combination with the frequency. Since the responsiveness is fast, a more rapid pressure change can be given, so that the fuel is excellent in atomization.

[Third Invention] FIG. 6 shows a fuel adding apparatus C according to a first embodiment of the third invention. In this embodiment, a discharge valve 8 for injecting fuel into the exhaust pipe 1 upstream of the catalyst device 2 is provided.
Is provided. The discharge valve 8 includes a ball valve 81, a seat 8
2, connected to the low-pressure pipe 12 by an outer opening valve composed of a spring 83 and a retaining nut 84. In the fuel tank 4, a pump 5 and a pressure delivery type meter 7 are provided.

During operation of the engine, fuel is supplied from the pump 5 to the pressurized delivery type meter 7 at a predetermined pressure. The meter 7 performs on / off control (drive frequency control) so that the fuel amount matches the engine conditions, and pressurizes and sends out the fuel. The metered fuel is injected from the discharge valve 8 into the exhaust pipe 1 in a state of atomization. Since the metering device 7 is a pressurized type, the pump 5 may be a low pressure type. Even if the distance to the discharge valve 8 is long, the pressure can be propagated, so that there is a degree of freedom in the installation location, which is effective for atomization.

FIG. 7 shows a fuel adding device C according to a second embodiment of the third invention. In this embodiment, the discharge valve 8A
From the pressurized delivery type meter 7A (see FIG. 5) to the low pressure pipe 12
The fuel supply is provided through the exhaust pipe 1 and the fuel is injected downstream (toward the catalyst device 2) along the center of the exhaust pipe 1.

In this embodiment, since the direction in which the discharge valve 8A is injected is parallel to the exhaust flow, uniform spray can be formed in the exhaust pipe 1 and fuel can be uniformly attached to the catalyst. In the meter 7A, in addition to controlling the injection amount by changing the drive frequency, the amount of extension of the piezoelectric laminate 79 can be changed by the applied voltage, and the metering can be performed in combination with the frequency. As a result, a more rapid change in pressure can be given, so that atomization is excellent.

[Fourth Invention] FIGS. 8 to 12 show a fourth invention. FIG. 8 shows a fuel addition device D according to the first embodiment of the fourth invention. In this embodiment, a discharge valve 8 for injecting fuel is installed inside the exhaust pipe 1 upstream of the catalyst device 2, and fuel returned from the fuel injection pump P of the diesel engine to the fuel tank 4 is guided to the discharge valve 8. . Fuel injection pump P
Is driven at a half rotational speed of an engine (not shown), and draws fuel from the fuel tank 4 through the feed pipe 13.

The surplus fuel of the fuel injection pump P is returned to the fuel tank 4 via the return pipe 14. A return pipe 14 serving as a return flow path is branched on the way, and one is connected to the shutoff valve 9 and the other is connected to the discharge valve 8 via an additional fuel supply pipe 15 serving as a branch flow path. The shutoff valve 9 is controlled by the control device 10 and is connected to a return pipe 14 to the fuel tank 4.

As shown in FIG. 9, the shut-off valve 9
And a valve body 9 in a casing 93 having an outlet 92.
4 is slidably arranged. An armature 95 connected to the valve element 94 by a rod, an electromagnetic coil 96 for attracting the armature 95 in the valve closing direction, a valve element 9 are provided in the casing 93.
A spring 97 for urging the valve 4 in the valve opening direction is provided. The casing 93 has a recess 9 a communicating with the inlet 91 and a spring chamber 9 b communicating with the outlet 92.

The recess 9a and the spring chamber 9b are divided openably and closably by a seat 9c provided on the outer periphery of the upper end of the spring chamber 9b and a tapered contact surface 9d provided on the outer periphery of the lower end of the valve element 94. I have. The valve element 94 is a spring 9
7, the spring chamber 9b and the recess 9a are in communication with each other in the non-energized state. When the electromagnetic coil 96 is energized, the armature 95 is attracted and pushes down the valve element 94, and the contact surface 9d is seated on the seat 9c,
The spring chamber 9b and the recess 9a are shut off.

During operation of the fuel injection pump P, surplus fuel flows from the return pipe 14 toward the tank 4. When no additional fuel is supplied, the shut-off valve 9 is in a non-energized state, and the recess 9a and the spring chamber 9b are in communication with each other.
b, It is returned into the tank 4 through the return pipe 14.
At this time, return fuel is also supplied to the additional fuel supply pipe 15, but no fuel is injected into the exhaust pipe 1 because the discharge valve 8 has a valve opening pressure.

When supplying the additional fuel, when the shut-off valve 9 is energized, the valve body 94 is pushed down, the contact surface 9d is seated on the seat 9c, and the spring chamber 9b and the recess 9a are shut off. At this time, the flow in the return pipe 14 and the additional fuel supply pipe 9 is suddenly cut off, and the pressure rises. When the pressure exceeds the opening pressure of the discharge valve 8, the valve opens and is injected into the exhaust pipe 1. .

However, if the shut-off valve 9 is kept closed, there is no return destination for the return fuel, the pressure rises, and the injection from the discharge valve 8 continues. Further, since the injection pump P is adversely affected, it is necessary to control the shut-off valve 9 at an appropriate number of times of driving. In other words, the control of the injection amount performs on / off control (drive frequency control), and uses the water hammer action for each drive,
The fuel is delivered under pressure to the discharge valve 8. As the number of times of driving increases, the amount of added fuel increases. These are controlled based on a command from the control device 10. The metered fuel is injected from the discharge valve 8 into the exhaust pipe in a finely divided state.

FIG. 10 shows a fuel adding apparatus D according to a second embodiment of the fourth invention. In this embodiment, a check valve 16 is provided between the branch of the return pipe 14 and the additional fuel supply pipe 15. The check valve 16 can generate the water hammer action more strongly.

FIG. 11 shows a fuel adding apparatus D according to a third embodiment of the fourth invention. In this embodiment, a shutoff valve 9 is provided in the fuel tank 4. Therefore, the connection portion between the shut-off valve 9 and the return pipe 14 to the shut-off valve 9 is
It is located inside and has excellent safety against fuel leakage.

FIG. 12 shows a fuel adding apparatus D according to a fourth embodiment of the fourth invention. In this embodiment, the check valve 1 is provided between the return pipe 14 and the branch of the additional fuel supply pipe 15.
Instead of providing 6, a pulsation damping device 17 is provided to prevent the pulsation due to the water hammer action from propagating to the fuel injection pump P. As the pulsation damping device 17, a tank having a predetermined capacity, a damper formed by a combination of a spring and a diaphragm, or an accumulator can be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a fuel addition device of a first invention.

FIG. 2 is a sectional view of a fuel meter.

FIG. 3 is a sectional view of a pressurized meter according to another embodiment.

FIG. 4 is a schematic configuration diagram of a first embodiment of a fuel addition device of the second invention.

FIG. 5 is a schematic configuration diagram of a second embodiment of the fuel addition device of the second invention.

FIG. 6 is a schematic configuration diagram of a first embodiment of a fuel addition device of a third invention.

FIG. 7 is a schematic configuration diagram of a second embodiment of the fuel addition device of the third invention.

FIG. 8 is a schematic configuration diagram of a first embodiment of a fuel addition device of a fourth invention.

FIG. 9 is a sectional view of a shut-off valve.

FIG. 10 is a schematic configuration diagram of a second embodiment of the fuel addition device of the fourth invention.

FIG. 11 is a schematic configuration diagram of a third embodiment of the fuel addition device of the fourth invention.

FIG. 12 is a schematic configuration diagram of a fourth embodiment of the fuel addition device of the fourth invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust pipe 10 Control device 14 Return pipe (return flow path) 15 Addition fuel supply pipe (branch flow path) 16 Check valve 17 Pulsation damping device 2 Catalyst device 3 Venturi 4 Fuel tank 5 Pump 6 Metering device 7 Pressurized delivery Type metering device 73 Casing 74 Pump chamber 76 Piston 79 Piezoelectric laminate (piezoelectric element) 8 Discharge valve 9 Shutoff valve A to D Fuel addition device

Claims (17)

[Claims] 1. A fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, comprising: a venturi provided in the exhaust pipe upstream of the catalyst device; A fuel supply device for supplying fuel to the venturi. 2. The fuel supply device according to claim 1, wherein the fuel supply means includes a fuel supply pump provided in the fuel tank, and a fuel discharged from the fuel supply pump provided in the fuel tank. 2. The fuel adding device according to claim 1, comprising: a fuel meter for metering and supplying the fuel to the venturi; and a controller for controlling the fuel supply pump and the fuel meter. 3. 3. The fuel adding device according to claim 2, wherein the fuel meter is an electromagnetic switching type fuel meter that opens and closes a fuel passage by an electromagnetic valve, and a driving frequency or a duty that opens and closes the fuel passage. A fuel addition device characterized by metering by changing the ratio. 4. The fuel adding device according to claim 2, wherein the fuel meter comprises a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by an electromagnetic solenoid. A fuel addition device, which is a pressurized metering device for pressurizing and discharging fuel sucked into a pump chamber, wherein a discharge amount is measured at a driving frequency. 5. A fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, comprising a fuel supply pump provided in a fuel tank and the exhaust gas upstream of the catalyst device. A fuel addition device consisting of a pressurized meter attached to a pipe. 6. The fuel addition device according to claim 5, wherein the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by an electromagnetic solenoid. A fuel addition device, wherein the fuel sucked into the pump chamber is pressurized and discharged, and the discharge amount is adjusted at a drive frequency. 7. The fuel adding apparatus according to claim 5, wherein the pressurized metering device includes a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element. A fuel adding apparatus, wherein the fuel sucked into the pump chamber is pressurized and discharged, and the discharge amount is measured by a driving frequency or an energizing voltage. 8. The fuel adding device according to claim 5, wherein the valve opening pressure of the pressurized meter is:
A fuel addition device, wherein the pressure is higher than the discharge pressure of the fuel supply pump. 9. A fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, the fuel supply pump provided in a fuel tank, and the fuel supply device provided in the fuel tank. A fuel meter for metering and discharging fuel discharged from a supply pump, fuel supply means including a control device for controlling the fuel supply pump and the fuel meter, and the exhaust pipe upstream of the catalyst device And a discharge valve for ejecting the fuel supplied from the fuel supply means into an exhaust pipe. 10. The fuel adding device according to claim 9, wherein the fuel meter is an electromagnetic switching type fuel meter that opens and closes a fuel passage by an electromagnetic valve, and changes a duty ratio that opens and closes a fuel flow path. A fuel addition device characterized in that the fuel is added and metered. 11. The fuel adding device according to claim 9, wherein the fuel meter comprises a casing having a pump chamber therein, and a piston housed in the pump chamber and driven by a piezoelectric element. A fuel addition device characterized in that it is a pressurized metering device that pressurizes and discharges the fuel sucked into a pump chamber and that controls the discharge amount with a drive frequency or an energizing voltage. 12. The fuel addition device according to claim 9, wherein the discharge valve injects fuel vertically or parallel to an exhaust flow in the exhaust pipe. Fuel addition device. 13. A fuel addition device for adding a reducing fuel to a catalyst device mounted on an exhaust pipe of a diesel engine, wherein a branch flow path is provided in a return flow path of a fuel injection pump mounted on the diesel engine. A fuel cut-off valve provided downstream of the branch to spray the exhaust pipe upstream of the catalyst device. 14. The fuel addition device according to claim 13, wherein the passage shutoff valve is a solenoid valve that shuts off a passage.
A fuel addition device, wherein the fuel is metered by changing the driving frequency. 15. The fuel adding device according to claim 13, wherein the passage shutoff valve is provided in a fuel tank. 16. The fuel adding apparatus according to claim 13, wherein a check valve is provided upstream of the branch of the return flow path. 17. The fuel adding device according to claim 13, wherein a pulsation damping device is provided upstream of the branch of the return flow path.