JPH07174056A - Double fuel injection valve - Google Patents

Abstract

PURPOSE:To obviate the necessity of a subfuel force sending pipe between a plurality of fuel injection valves, suppress the lowering of the pressure of the subfuel in the force sending of the subfuel, and improve responsiveness in the force sending of the subfuel, by charging the subfuel in a double fuel injection valves by the double fuel injection valve itself by utilizing the restoring force in the lowering of a needle after rising, as the pressure sending force of subfuel. CONSTITUTION:When a needle 108 rises, subfuel is introduced into a subfuel chamber 126 which is formed from a piston part 109 and a cylinder 111. Further, when the needle 108 lowers, the piston part 109 presses the subfuel in the subfuel chamber 126, and the subfuel is introduced into the main fuel supply passage 120 on the outer periphery at the top end part of the needle 108 through a subfuel introducing passage 130. Accordingly, the necessity of a subfuel force sending pipe connecting each subfuel injection valve 102 is obviated, and the reduction of the pressure of the subfuel in the force sending of the subfuel reduces in comparison with the case of the existence of the subfuel force sending pipe, and the responsiveness in the force sending of the subfuel is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple fuel injection valve for a multi-cylinder internal combustion engine, and more specifically, it uses alcohol or the like, which is difficult to self-ignite by compression, as a main fuel, and diesel oil, etc., which is excellent in self-ignition by compression, as a secondary fuel. The present invention relates to a dual fuel injection valve of a diesel engine used as.

[0002]

2. Description of the Related Art Conventionally, internal combustion engines for automobiles are roughly classified into spark-type engines that use gasoline as fuel and compression-ignition engines that use light oil. As a fuel, it has been attempted to use a mixed fuel in which gasoline is mixed with another fuel, for example, alcohol. Further, in diesel engines, which are compression ignition type engines, it has been attempted to use alcohol as fuel instead of light oil.

By the way, when alcohol is used as fuel instead of light oil in a diesel engine, the compression ignitability of the fuel is inferior to that of light oil. Therefore, there is a dual fuel supply device that can separately supply alcohol and light oil to the engine, supplies a small amount of light oil as auxiliary fuel at the start of injection to ignite, and then supplies alcohol as main fuel. It has been proposed by the applicant of the present application to be Japanese Patent Application No. 4
No. 169490 has been proposed.

FIG. 4 is a sectional view of a dual fuel injection valve used in a dual fuel supply system for a four cylinder diesel engine in Japanese Patent Application No. 4-169490. Dual fuel injection valve 402
Is used when two types of fuel are injected in a diesel engine that uses alcohol as the main fuel and light oil as the auxiliary fuel.

An injection port 40 is provided at the tip of the dual fuel injection valve 402.
4 is provided, and a needle 406 is housed in the dual fuel injection valve 402 so as to be vertically movable.
6 has a seat portion 408 with its tip portion at the lower end position.
It is configured to close the injection port 404 in close contact with.
Further, the pressure pin 41 is provided on the upper end of the needle 406.
No. 0 is attached to the pressure pin 410, and the pressure pin 410 is provided in the dual fuel injection valve 402.
It is a spring receiver for receiving the spring 414 installed inside. The tip of the needle 406 is always in close contact with the seat 408 by the biasing force of the spring 414 to close the injection port 404.

A main fuel supply port 420 and a first auxiliary fuel supply port 422 are opened at the upper end of the multi-fuel injection valve 402. The main fuel supply port 420 is provided with a main fuel passage 424 provided in the dual fuel injection valve 402, and a main fuel reservoir 425 and a fuel passage 426 are provided around the needle 406.
Through the nozzle hole 404.

An auxiliary fuel passage 42 is provided inside the needle 406.
8 are provided. One end thereof is open at the tip of the needle 406, and the other end is the first auxiliary fuel supply port 422.
Is connected to one end of an auxiliary fuel passage 430. A check valve 432 is provided in the sub fuel passage 430.

Further, the auxiliary fuel is fed from the second auxiliary fuel supply port 434 through the check valve 436 to the auxiliary fuel pumping chamber 412. Further, in a passage connecting the auxiliary fuel pressure feed chamber 412 and the second auxiliary fuel supply port 434, an auxiliary fuel pressure feed passage 437 is branched from between the auxiliary fuel pressure feed chamber 412 and the check valve 436. The auxiliary fuel pressure supply passage 437 is connected to a first auxiliary fuel supply port 422 of another dual fuel injection valve 402 by a auxiliary fuel pressure supply pipe 440 via a check valve 438.

The multiple fuel injection valve 40 constructed as described above.
The operation of No. 2 will be described. The sub fuel sent from the sub fuel tank (not shown) enters the sub fuel pressure feed chamber 412 from the second sub fuel supply port 434 through the check valve 436. Thereafter, when high-pressure main fuel enters from the main fuel supply port 420, the main fuel enters the main fuel reservoir 425 through the main fuel passage 424, and when the pressure overcomes the biasing force of the spring 414, the needle 406 is removed. To lift. Then, after the sub fuel filled in the tip of the passage of the fuel passage 426 is injected from the opened injection port 404, this main fuel is injected into the injection port 40.
It is injected from 4.

When the needle 406 is lifted by the main fuel, the sub fuel in the sub fuel pressure feed chamber 412 is compressed, and the sub fuel is filled from the sub fuel pressure feed passage 437 through the check valve 438 and the sub fuel pressure feed pipe 440. It is sent to the first auxiliary fuel supply port 422 of another dual fuel injection valve 402. Since the main fuel is not injected in another dual fuel injection valve 402, which is the filling destination of the auxiliary fuel, the needle 406 is seated on the seat portion 408 and the injection port 404 is closed. Therefore, the auxiliary fuel from the first auxiliary fuel supply port 422 passes through the auxiliary fuel passage 430, the check valve 432, and the auxiliary fuel passage 428, and is opened from the opening at the tip of the needle 406.
6 is filled in the front end portion of the fuel passage 426. When high pressure main fuel enters from the main fuel supply port 420 in a state where the sub fuel is filled in the tip end of the fuel passage 426, the needle 406 is lifted and the sub fuel and the main fuel are injected from the injection port 404, The sub fuel in the sub fuel pressure feed chamber 412 is compressed by the lift of the needle 406, and then is fed to the first sub fuel supply port 422 of the other dual fuel injection valve 402.
Sent through 40.

As described above, the needle 406 of the dual fuel injection valve 402 is lifted by the pressure of the alcohol, which is the main fuel, and the lift of the needle 406 causes another dual fuel injection valve 402 to be filled with light oil, which is the sub fuel. It

[0012]

However, in the above-described dual fuel supply system, the dual fuel injection valve has a structure in which the auxiliary fuel is filled in another dual fuel injection valve by lift of the needle of the dual fuel injection valve. An auxiliary fuel pressure feed pipe was required between the valves. Since the pressure of the sub-fuel during the pressure-feeding of the sub-fuel decreases in proportion to the length of the sub-fuel pressure-feeding pipe in which the sub-fuel is pressure-fed, there is a risk that the pressure drop of the sub-fuel will prevent the necessary amount of the sub-fuel from being filled. It was

Therefore, in the present invention, as the pumping force of the auxiliary fuel,
By utilizing the restoring force when the needle rises and then descends, the auxiliary fuel in a certain dual fuel injection valve is filled by that dual fuel injection valve itself, and the auxiliary fuel pressure feed pipe between the multiple fuel injection valves is formed. It is not necessary to reduce the pressure drop of the auxiliary fuel when the auxiliary fuel is pressure-fed, and to improve the response of the auxiliary fuel pressure-feed.

[0014]

In order to achieve the above object, the multiple fuel injection valve according to claim 1 of the present invention has a needle which is built in the valve body and is in contact with the valve body due to the pressure of the main fuel. A multi-fuel injection valve that raises and injects a main fuel and an auxiliary fuel by opening an injection port provided at the tip of the valve body, the main fuel supply passage being formed in the valve body and supplied with the main fuel, An auxiliary fuel supply passage formed in the valve body for supplying auxiliary fuel; an auxiliary fuel introduction passage formed in the needle and communicating with the main fuel supply passage and the auxiliary fuel supply passage; An urging means for urging the valve body toward the front end, a first check valve provided in the auxiliary fuel introducing passage for preventing a reverse flow of the auxiliary fuel when the needle is raised, and provided in the auxiliary fuel supply passage. Reverse flow of auxiliary fuel when the needle descends A second check valve that stops, a sub-fuel chamber that is formed by the valve body and the needle and that is supplied with sub-fuel from the sub-fuel supply passage when the needle rises, and a sub-fuel that is formed in the needle when the needle descends. It is composed of a piston portion for pumping the sub fuel in the chamber to the sub fuel introduction passage.

Further, as described in claim 2, the main fuel is alcohol, the sub fuel is light oil, and the communicating portion between the sub fuel introduction passage and the main fuel supply passage is near the tip of the needle. A dual fuel injection valve is provided.

[0016]

According to the structure of the first aspect, when the pressure in the main fuel supply passage increases, the needle rises against the biasing means for biasing the needle toward the tip of the valve body, and the needle is provided at the tip of the valve body. The main fuel and the sub fuel are injected from the injection port. When the needle is lifted up, the first is provided in the auxiliary fuel introduction passage in the needle.
The check valve is closed to prevent the reverse flow of the auxiliary fuel, and the second check valve provided in the auxiliary fuel supply passage of the valve body allows the auxiliary fuel supply from the auxiliary fuel supply passage to the auxiliary fuel chamber. Open to do. When the needle descends, the sub fuel in the sub fuel chamber is pressure-fed to the sub fuel introduction passage by the piston portion that receives the force of the urging means. At this time, the first check valve is opened to allow the introduction of the auxiliary fuel from the auxiliary fuel chamber into the auxiliary fuel introduction passage, and the second check valve is closed to prevent the reverse flow of the auxiliary fuel.

Further, according to the second aspect of the present invention, since the communicating portion between the auxiliary fuel introduction passage and the main fuel supply passage is near the tip of the needle, the needle and the valve body when the double fuel injection valve is closed when the needle descends. Alcohol, which is the main fuel, is pushed away to the contact portion of, and light oil, which is the auxiliary fuel, is supplied. Then, the needle and the valve body come into contact with each other, and the multiple fuel injection valve is closed.

[0018]

1 is a sectional view showing the structure of a multiple fuel injection valve according to a first embodiment of the present invention. The valve body 104 of the dual fuel injection valve 102 is composed of three parts: a holder body 104a, a distance piece 104b, and a nozzle body 104c. A nozzle 106 is provided at the tip of the nozzle body 104c. A needle 108 is housed in the valve body 104 so as to be movable up and down.
In the lower end position 08, the leading end of the seat 08 is the seat portion 11
It is configured to be in close contact with 0 and close the injection port 106. Further, the upper end portion of the needle 108 is expanded in diameter to form a piston portion 109. The piston portion 109 can reciprocate inside a cylinder 111 formed in the nozzle body 104c. A pressure pin 112 is attached above the piston portion 109 of the needle 108, and the pressure pin 112 is housed in an internal space 114 provided in the valve body 104 and is a spring 116 as a biasing means.
It is a spring bearing to receive. And the needle 10
The urging force of the spring 116 causes the tip of the nozzle 8 to come into close contact with the seat 110 and close the injection port 106 when fuel is not injected.

A main fuel supply port 117 and an auxiliary fuel supply port 118 are opened at the upper end of the holder body 104a. The main fuel supply port 117 is connected to a main fuel reservoir 122 provided around the needle 108 by a main fuel supply passage 120 provided in the valve body 104. The main fuel supply passage 120 is connected to the needle 10 from the vicinity of the main fuel reservoir 122.
8 is formed in an annular shape around the needle 108 up to the vicinity of the tip.

On the other hand, the auxiliary fuel supply port 118 is connected to the valve body 104.
The needle 1 by the auxiliary fuel supply passage 124 provided in the
The auxiliary fuel chamber 126 formed by the piston portion 109 and the cylinder 111 of No. 08. A second check valve 128 is provided in the auxiliary fuel supply passage 124 to prevent the reverse flow of the auxiliary fuel.

A sub-fuel introducing passage 130 is provided inside the needle 108. One end of the sub-fuel introducing passage 130 is opened to the main fuel supply passage 120 at an opening 131, and the other end is formed in the sub-fuel chamber. An opening 133 opens at 126. A first check valve 132 is provided in the auxiliary fuel introducing passage 130 to prevent the reverse flow of the auxiliary fuel.

FIG. 2 is a block diagram of a multiple fuel supply system using the multiple fuel injection valve of the present invention. 202 is a tank that stores alcohol as a main fuel, and 204 is a tank that stores light oil as a sub fuel. A feed pump 206 for pumping up the main fuel is provided in the tank 202, and the main fuel pumped up from the tank 202 by the feed pump 206 is sent to a column fuel injection pump 210 via a filter 208. A feed pump 212 for pumping the sub fuel is provided in the tank 204, and the sub fuel pumped from the tank 204 by the feed pump 212 is sent to the multiple fuel injection valve 102 via the filter 214. The pressure of the main fuel is adjusted by the pressure regulator 216, and excess fuel is returned to the tank 202 via the return passage 218.
The pressure of the auxiliary fuel is adjusted by the pressure regulator 220, and excess fuel is returned to the tank 204 through the return passage 222.

The column-type fuel injection pump 210 has a series of cylinders 224 each containing a plunger (not shown), and each main fuel pressurizing chamber (not shown) formed at the tip of the plunger in each cylinder 224 is a compound fuel injection valve. Is connected to the main fuel supply port 117.

Next, the operation of the multiple fuel injection valve 102 will be described. The auxiliary fuel pumped up from the tank 204 by the feed pump 212 is passed through the filter 214 to the N
O. 1, NO. 2, NO. 3, NO. 4 to the auxiliary fuel supply port 118 of each dual fuel injection valve 102. This sub fuel is introduced into the sub fuel chamber 126 via the second check valve 128 in the sub fuel supply passage 124. After introducing the sub fuel into the sub fuel chamber 126, the second check valve 128 is closed. Now N
O. When the plunger (not shown) in the cylinder 224 of No. 1 rises, the main fuel is NO. It is pressure-fed to the main fuel supply port 117 of the dual fuel injection valve 102. This main fuel is introduced around the needle 108 through the main fuel supply passage 120. This main fuel pressure acts on the main fuel sump 122,
The pressure overcomes the spring force of the spring 116 pressing the pressure pin 112 and the needle 108, so that the needle 108 is lifted from the seat portion 110.
Then, the main fuel supply passage 1 on the outer periphery of the tip of the needle 108
After the auxiliary fuel with which 20 is filled is injected from the injection port 106, the main fuel is injected from the injection port 106.

When the needle 108 is raised by the main fuel, the piston portion 109 formed on the needle 108 naturally rises in the cylinder 111. Therefore, the volume of the sub fuel chamber 126 formed by the piston portion 109 and the cylinder 111 increases, and the sub fuel chamber 1
The pressure in 26 drops. Then, the second check valve 128
Is opened by the pressure difference between the side of the auxiliary fuel supply port 118 and the side of the auxiliary fuel chamber 126, and the auxiliary fuel is introduced from the auxiliary fuel supply passage 124 to the auxiliary fuel chamber 126. Sub fuel chamber 12
The introduction of the auxiliary fuel into 6 is continued until the raising of the needle 108 is completed. While the needle 108 is rising, the pressure of the main fuel acts on the sub fuel in the sub fuel introduction passage 130, so that the first check valve 132 is closed and the sub fuel in the sub fuel introduction passage 130 is It does not flow back into the auxiliary fuel chamber 126.

NO. When the pumping of the main fuel by the plunger (not shown) in the cylinder 224 of No. 1 is completed and the pressure of the main fuel in the main fuel supply passage 120 is reduced, the spring force of the spring 116 overcomes the pressure of the main fuel, and the needle 108 moves. It is lowered. At this time, the piston 109 formed on the needle 108 is lowered, so that the pressure in the sub fuel chamber 126 is increased, the first check valve 132 is opened, and the sub fuel in the sub fuel chamber 126 is opened. It is pressure-fed to the sub fuel introduction passage 130 from 133. It should be noted that the second check valve 128 is closed when the needle 108 has finished rising, and remains closed because the pressure in the sub fuel chamber 126 rises when the needle 108 descends. It prevents the fuel from flowing back.

From the sub fuel chamber 126 to the sub fuel introduction passage 130
The auxiliary fuel pumped to the needle 108 is discharged from the opening 131.
It is introduced into the main fuel supply passage 120 on the outer periphery of the tip portion. Therefore, next NO. Before the main fuel is pressure-fed by a plunger (not shown) in the cylinder 224 of No. 1, the NO. In the dual fuel injection valve 102 of No. 1, the auxiliary fuel has already been filled in the main fuel supply passage 120 on the outer periphery of the tip of the needle 108. Therefore, NO. When the first multiple fuel injection valve 102 is opened by the pressure of the main fuel, the sub fuel is first injected from the injection port 106, and then the main fuel is injected from the injection port 106. These series of operations are NO. 2, NO.
3, NO. No. 4 and No. 4 in the cylinder 224 of the No. 4 cylinder 224. 2, NO. 3, NO. 4 fuel injection valve 1
Also in 02.

As described above, according to the multiple fuel injection valve of the first embodiment of the present invention, when the needle 108 rises, the auxiliary fuel is introduced into the auxiliary fuel chamber 126 formed by the piston portion 109 and the cylinder 111. . Further, when the needle 108 descends, the piston portion 109 presses the sub fuel in the sub fuel chamber 126, and the sub fuel is introduced into the main fuel supply passage 120 on the outer periphery of the tip of the needle 108 via the sub fuel introduction passage 130. It In this way, the introduction of the auxiliary fuel into a certain dual fuel injection valve 102 is performed by raising and lowering the needle 108 in the multiple fuel injection valve 102. Therefore, the auxiliary fuel pressure feed pipe connecting the multiple fuel injection valves 102 as in the prior art is not necessary, and the pressure drop of the auxiliary fuel when the auxiliary fuel is pressure-fed is smaller than that when the auxiliary fuel pressure feed pipe is provided. , The response of the sub fuel pumping is improved.

Further, when the small amount of fuel is injected, such as when the load is low, the amount of rise of the needle 108 is small, so the amount of auxiliary fuel introduced into the auxiliary fuel chamber 126 is also small, and the amount of auxiliary fuel pumped can be controlled. Is.

Further, the main fuel and the sub fuel are pumped / filled into one dual fuel injection valve 102 independently of the main fuel and the sub fuel which are loaded into another dual fuel injection valve 102. Therefore,
Even if a plunger or the like in a cylinder 224 having a certain dual fuel injection valve 102 or a column fuel injection pump 210 fails, another double fuel injection valve 102 or another cylinder 224 of the column fuel injection pump 210 in The plunger etc. will not be affected.

FIG. 3 is a sectional view showing the structure of a multiple fuel injection valve according to the second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. First except that an opening 131, which is a communicating portion between the auxiliary fuel introduction passage 130 and the main fuel supply passage 120, is provided near the tip of the needle 108.
The configuration is the same as that of the embodiment.

The operation of the multiple fuel injection valve according to the second embodiment having the above structure will be described. The second embodiment has the following operation in addition to the operation of the first embodiment.

When the pressure of the main fuel in the main fuel supply passage 120 decreases, the spring force of the spring 116 overcomes the pressure of the main fuel, and the needle 108 is lowered. This time,
As the piston portion 109 formed on the needle 108 descends, the pressure in the sub fuel chamber 126 rises, the first check valve 132 opens, and the sub fuel in the sub fuel chamber 126 sub-passes through the opening 133. It is pressure-fed to the fuel introduction passage 130. It should be noted that the second check valve 128 is closed when the needle 108 has finished rising, and remains closed because the pressure in the sub fuel chamber 126 rises when the needle 108 descends. It prevents the fuel from flowing back. Opening 13
Since 1 is near the tip of the needle 108, the auxiliary fuel pressure-fed to the auxiliary fuel introduction passage 130 is supplied from the opening 131 to the main fuel supply passage 120, and is the contact portion between the needle 108 and the nozzle body 104c. Seat part 110
Reach Then, the needle 108 descends completely and comes into close contact with the seat 110.

As described above, according to the multiple fuel injection valve of the second embodiment of the present invention, the needle 131 has the opening 131 which is a communicating portion between the auxiliary fuel introduction passage 130 and the main fuel supply passage 120.
Since it is provided in the vicinity of the tip of the No. 8, the dual fuel injection valve is closed after the light oil as the auxiliary fuel is supplied to the seat portion 110 when the needle 108 descends. Therefore, light oil, which has better lubricity than alcohol, which is the main fuel, is
When the nozzle 08 and the nozzle body 104c are in contact with each other, since they are always supplied to the seat portion 110 which is the contact portion, wear due to contact between the needle 108 and the nozzle body 104c caused by repeated opening and closing of the multiple fuel injection valve can be reduced.

In the embodiment of the present invention, the case where the row type fuel injection pump is used as the injection pump of the multiple fuel supply apparatus has been described, but the present invention is also applied to the multiple fuel supply apparatus using the distribution type fuel injection pump. The multiple fuel injection valve of is applicable.

[0036]

According to the present invention, the introduction of the auxiliary fuel into a certain dual fuel injection valve is performed by raising and lowering the needle in the multiple fuel injection valve, so that the multiple fuel injection valves as in the prior art are connected. The auxiliary fuel pressure feed pipe is unnecessary. Therefore, the decrease in the pressure of the sub-fuel when the sub-fuel is pumped is smaller than that in the case where the sub-fuel pumping pipe is provided, and the responsiveness of the sub-fuel pumping is improved.

Further, since the communicating portion between the auxiliary fuel introduction passage and the main fuel supply passage is provided near the tip of the needle,
When the needle descends, the dual fuel injection valve is closed after the light oil, which is the secondary fuel, is supplied to the contact portion between the needle and the valve body when the double fuel injection valve is closed. Therefore, light oil, which has better lubricity than alcohol, which is the main fuel, is always supplied to the contact portion when the needle and the valve body contact each other, so that the needle and the valve body that are repeatedly opened and closed and the valve body Wear due to contact with can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a dual fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a multiple fuel supply system using the multiple fuel injection valve of the present invention.

FIG. 3 is a sectional view of a multiple fuel injection valve according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a conventional dual fuel injection valve.

[Explanation of symbols]

 102 ... Dual fuel injection valve 104 ... Valve body 106 ... Injection port 108 ... Needle 109 ... Piston part 116 ... Spring 120 ... Main fuel supply passage 124 ... Sub fuel supply Passage 126 ... Secondary fuel chamber 128 ... Second check valve 130 ... Secondary fuel introduction passage 131 ... Opening 132 ... First check valve

Claims (2)

[Claims] 1. A compound fuel injector, which is built in a valve body and is in contact with the valve body, is raised by the pressure of the main fuel, and an injection port provided at the tip of the valve body is opened to inject the main fuel and the auxiliary fuel. A fuel injection valve, the main fuel supply passage being formed in the valve body and supplied with main fuel; the sub-fuel supply passage being formed in the valve body and being supplied with auxiliary fuel; A sub-fuel introduction passage communicating with the main fuel supply passage and the sub-fuel supply passage, an urging means for urging the needle toward the tip of the valve main body, and the needle ascending provided in the sub-fuel introduction passage. Check valve for preventing back flow of the sub fuel when the needle moves, a second check valve provided in the sub fuel supply passage for preventing back flow of the sub fuel when the needle descends, the valve body and the needle Formed by and when the needle rises Secondary and secondary fuel chamber that is secondary fuel from the fuel supply passage is supplied, multi fuel injection valve comprising a piston unit for pumping secondary fuel in the secondary fuel chamber during formed needle lowered to the needle in the sub fuel introducing passage. 2. The main fuel is alcohol, the sub fuel is light oil, and the communicating portion between the sub fuel introduction passage and the main fuel supply passage is near the tip of the needle. The multiple fuel injection valve described.