JP4767458B2 - Fuel supply device for internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a fuel supply device that supplies gas fuel such as liquefied petroleum gas (LPG) and compressed natural gas (CNG) to an internal combustion engine, and the pressure of the gas fuel in the gas fuel source is reduced and regulated. The present invention relates to a fuel supply device in an internal combustion engine that supplies the gas fuel that has been supplied to the engine via a mixer body.
[0002]
[Prior art]
A conventional fuel supply apparatus will be described with reference to FIG.
The fuel supply device includes a mixing body M and a vaporizer V.
The mixing body M is perforated through the intake passage 10, and a mixer venturi portion 11 is formed in the upstream portion of the intake passage 10.
A throttle valve shaft 12 that supports a throttle valve 13 that opens and closes the downstream portion of the intake passage 10 is rotatably supported on the mixing body M. On the other hand, a plurality of main ports 14 are formed in the mixer venturi portion 11 so as to open, and the main port 14 is provided with a secondary pressure fuel via an annular groove portion 15 formed surrounding the mixer venturi portion 11. Contact is made to the introduction path 16.
[0003]
The vaporizer V consists of the following.
Reference numeral 20 denotes a primary diaphragm that divides the casing B into a primary pressure regulating chamber 21 and a primary decompression chamber 22, and the primary diaphragm 20 is arranged in a contracted manner in the primary pressure regulating chamber 21. The primary spring 23 is pressed toward the primary decompression chamber 22 by the spring force.
Reference numeral 24 denotes a primary valve disposed at one end of a primary support rod 25 that is rotatably supported in the primary decompression chamber 22. The primary valve 24 is a fuel inflow passage that opens into the primary decompression chamber 22. 26 is controlled to open and close. The other end of the first support rod 25 is locked to the primary diaphragm 20.
Reference numeral 27 denotes a primary fuel discharge passage that opens outward from the primary decompression chamber 22, and the primary fuel discharge passage is opened and closed by a slow lock valve 28.
Reference numeral 29 denotes a slow lock diaphragm that applies an opening / closing operation force to the slow lock valve. The slow lock diaphragm 29 is pressed rightward in FIG. 5 in the slow lock chamber 30 defined by the slow lock diaphragm 29. The slow lock spring 31 is contracted, and a negative pressure introduction passage 32 connected to the intake passage 10 of the mixing body is opened.
(The slow lock valve 28 and the slow lock diaphragm 29 are connected by a connecting rod.)
Reference numeral 33 denotes a primary adjustment screw that regulates and controls the amount of gas fuel flowing through the primary fuel discharge passage 27, and a tapered needle valve portion is formed at the tip.
The casing B is further divided into a secondary pressure regulating chamber 35 and a secondary decompression chamber 36 by a secondary diaphragm 34, and the secondary decompression chamber 36 includes a secondary fuel inflow passage 37 connected to the primary decompression chamber 22 and an external portion. A secondary fuel discharge path 38 is opened.
Reference numeral 39 denotes a second support rod that is rotatably supported in the secondary decompression chamber 36, and a secondary valve 40 that opens and closes the secondary fuel inflow passage 37 is disposed at one end of the second support rod 39. The other end is locked to the secondary diaphragm 34.
Further, the second support rod is urged counterclockwise by the spring force of the secondary spring 41, whereby the secondary valve 40 is pressed toward the side closing the secondary fuel inflow passage 37.
Then, liquefied petroleum gas (LPG) as gas fuel is supplied to the fuel inflow passage 26 of the vaporizer V.
When liquefied petroleum gas (hereinafter referred to as LPG) is used, LPG having a pressure of about 5 kg / cm ² in the gaseous fuel source T1 is supplied directly to the fuel introduction path 26.
On the other hand, compressed natural gas (hereinafter referred to as CNG) can be used instead of LPG. At this time, CNG having a pressure of about 200 kg / cm ² in the gas fuel source T2 is about 6 kg / cm ² by the primary regulator R. The pressure of cm ² is reduced, and this reduced CNG is supplied to the fuel inflow passage 26.
The driver determines which of the LPG or CNG gas fuel is used.
[0004]
In the vaporizer V, the primary valve 24 has a fuel pressure of the gas fuel itself (a fuel pressure of about 5 kg / cm ² for LPG, about 6 kg / cm reduced by the primary regulator R for CNG). ² ), the fuel inflow passage 26 is opened, and the gas fuel is supplied into the primary decompression chamber 22.
When the pressure in the primary decompression chamber 22 rises above a predetermined pressure (for example, 0.3 kg / cm ² ), the primary diaphragm 20 resists the spring force of the primary spring 23 and the primary pressure regulation chamber 21. As a result, the first support rod 25 rotates counterclockwise, and the primary valve 24 closes the fuel inflow passage 26, so that the gas fuel pressure in the primary decompression chamber 22 is 0.3 kg / cm. Can be adjusted to ² .
On the other hand, when the gas fuel pressure in the primary decompression chamber 22 decreases to a pressure of 0.3 kg / cm ² or less, the primary spring 23 presses and moves the primary diaphragm 20 toward the primary decompression chamber 22, As a result, the first support rod 25 rotates clockwise and the primary valve 24 opens the fuel inflow passage 26. Accordingly, high-pressure gas fuel is supplied into the primary decompression chamber 22 from the fuel inflow passage 26, whereby the gas fuel pressure in the primary decompression chamber 22 is restored to a predetermined 0.3 kg / cm ² again. it can.
Thereafter, the operation of the primary valve is repeatedly performed, so that gas fuel having a predetermined pressure of 0.3 kg / cm ² as the primary pressure is maintained in the primary decompression chamber 22. .
On the other hand, in the secondary decompression chamber 36, the gas fuel is decompressed to atmospheric pressure.
As previously described, the gas fuel pressure in the primary vacuum chamber 22 is intended to be pressed 0.3 kg / cm ² two tone, the gas fuel secondary fuel inflow passage 37 with a pressure of 0.3 kg / cm ² The secondary valve 40 opens the secondary fuel inflow passage 37 and gas fuel is supplied into the secondary decompression chamber 36.
Here, when the gas fuel pressure in the secondary decompression chamber 36 rises to the atmospheric pressure or more, the secondary diaphragm 34 is displaced toward the secondary pressure regulating chamber 35, and according to this, the second support rod 39 is moved to the secondary spring 41. The secondary valve 40 closes the secondary fuel inflow passage 37 by rotating counterclockwise by the spring force of the gas, and thereby the gas fuel pressure in the secondary decompression chamber 36 is returned to the atmospheric pressure. Further, when the gas fuel pressure in the secondary decompression chamber 36 falls below the atmospheric pressure, the secondary diaphragm 34 is displaced toward the secondary decompression chamber 36 against the spring force of the secondary spring 41. The second support rod 39 rotates in the clockwise direction, and the secondary valve 40 opens the secondary fuel inflow passage 37, whereby the gas fuel pressure in the secondary decompression chamber 36 is returned to atmospheric pressure.
Thereafter, the secondary valve 40 repeats the above operation, whereby the gas fuel pressure in the secondary decompression chamber 36 can be maintained at the atmospheric pressure as the secondary pressure.
The intermediate opening degree and high opening degree operation of the throttle valve 12 are performed as follows.
That is, when the throttle valve 12 opens the intake passage 10 to a medium opening degree and a high opening degree, a high negative pressure corresponding to the throttle valve opening degree is generated in the mixer venturi unit 11, and this negative pressure is A gas in an atmospheric pressure state that acts on the secondary decompression chamber 36 via the main port 14, the annular groove 15, the secondary pressure fuel introduction passage 16, and the secondary fuel discharge passage 38 and is maintained in the secondary decompression chamber 36. The fuel is sucked into the mixer venturi unit 11 through the main port 14, whereby the inside of the throttle valve 13 and the high opening operation are performed.
[0005]
[Problems to be solved by the invention]
According to such a conventional fuel supply device, first, it is difficult to uniformly mix the gas fuel sucked from the main port 14 with the air flowing in the intake passage 10.
This is due to the following reason.
The main port 14 opens in the wall surface of the mixer venturi unit 11, and the gas fuel sucked out from the main port 14 easily flows into the intake passage 10 along the wall surface of the mixer venturi unit 11.
According to this, good mixing of the air and gas fuel flowing through the central portion of the mixer venturi section 11 is difficult to perform, and in particular, the mixed state of the air and gas fuel flowing through the central portion tends to be diluted.
Second, it is difficult to accelerate the suction response of the gas fuel sucked from the main port 14, and when the throttle valve 13 shifts from the low opening to the middle and high opening, the shortness of breath of the gas fuel occurs. May occur.
That is, the gas fuel sucked out from the main port 14 is in an atmospheric pressure state and depends on the negative pressure of the mixer venturi section 11 applied to the main port 14.
On the other hand, considering the distribution state of the negative pressure in the cross section of the mixer venturi section 11, the maximum value of the negative pressure exists in the center direction from the wall surface of the mixer venturi section 11, and the mixer venturi section 11 in this high negative pressure state. This is because the main port 14 is not opened.
[0006]
The fuel supply device for an internal combustion engine according to the present invention is made in view of the above-mentioned problems. The fuel supply device for the internal combustion engine achieves uniform mixing of the gas fuel sucked from the main port and the air flowing through the mixer venturi and is sucked from the main port. This is to improve the operability of the engine by improving the gas fuel suction response.
[0007]
[Means for achieving the object]
In order to achieve the above object, the present invention reduces the gas fuel of the gas fuel source to a predetermined primary pressure in the primary decompression chamber and to a secondary pressure in a substantially atmospheric state in the secondary decompression chamber. A vaporizer for depressurization; a mixing body having a main port opened in a mixer venturi section provided in an intake passage penetrating through the interior; a shaft support for the mixing body to open and close the intake path downstream of the mixer venturi section In the fuel supply device including the throttle valve, a pipe-shaped main nozzle into which the gas fuel in the secondary decompression chamber is introduced is disposed in the mixer venturi section, and the main nozzle is disposed in the mixer venturi section. A plurality of main ports that open to face the main port, and the main ports are arranged in a cross section perpendicular to the longitudinal axis of the main nozzle. With reference to a line orthogonal to the longitudinal axis of the intake passage, the primary decompression chamber opens only to a range of 45 degrees to the engine side and 45 degrees to the air cleaner side, and enters the intake passage downstream of the throttle valve. The first feature is that an idle port into which only the gas fuel is introduced is opened.
[0008]
According to the present invention, in addition to the first feature, an annular groove that surrounds the mixer venturi is provided inside the mixer venturi, and the secondary groove connected to the secondary decompression chamber is provided in the annular groove. A second feature is that the pressurized fuel introduction passage is opened and both ends of the main nozzle are arranged to be opened.
[0009]
[Action]
According to the first feature of the present invention, the main port is formed in the main nozzle and opens at a position away from the wall surface of the mixer venturi, so that the gas fuel sucked from the main port runs along the wall surface of the mixer venturi. Difficult to flow.
Further, since the main port is opened at a substantially central portion of the mixer venturi portion, the main port can be opened to a portion where the venturi negative pressure is high.
Furthermore, when the main port is opened only in the range of 45 degrees to the engine side and 45 degrees to the air cleaner side with reference to the line Y-Y, the gas fuel sucked from the main port to the mixer venturi section enters the intake passage. Hard to be disturbed by the flowing airflow.
[0010]
Further, according to the second feature of the present invention, gas fuel is supplied to the inner passage of the main nozzle from both ends of the main nozzle via the annular groove portion, so that more uniform gas fuel is supplied to the mixer venturi portion. Can be sucked out.
[0011]
【Example】
Hereinafter, an embodiment of a fuel supply device for an internal combustion engine according to the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a mixing body showing a first embodiment, and FIG. 2 is a sectional view WW orthogonal to the longitudinal axis ZZ of the main nozzle and passing through the longitudinal axis XX of the intake passage. It is a principal part cross section.
The vaporizer V shown in FIG. 4 is used and is omitted. In addition, about the same structure part as FIG. 4, the same code | symbol is used and description is abbreviate | omitted.
Reference numeral 1 denotes a pipe-shaped main nozzle through which a passage 1A penetrates, and a main port 2 extends from the inside toward the outside along the longitudinal axis ZZ of the main nozzle 1. A plurality of stages are drilled along.
The main nozzle 1 is disposed across the mixer venturi section 11, and both ends of the main nozzle 1 are fixedly disposed in the mixer venturi section 11 by press fitting or the like.
The upper end portion of the main nozzle 1 in FIG. 1 faces the secondary pressure fuel introduction path 16, whereby the secondary pressure is introduced into the inner passage 1 A of the main nozzle 1 via the secondary pressure fuel introduction path 16. A gas fuel having
Here, the main port 2 formed in the main nozzle 1 is formed at the following position.
That is, the main port 2 is an engine with reference to a line YY orthogonal to the longitudinal axis XX of the intake passage 10 in a cross-section WW orthogonal to the longitudinal axis ZZ of the main nozzle 1. The opening was made only in the range of 45 degrees to the side (left side in the figure) and 45 degrees to the air cleaner side (right side in the figure).
In FIG. 1, a range of 45 degrees toward the engine side is indicated by E, and a range of 45 degrees toward the air cleaner side is indicated by A.
In this embodiment, the main port 2 is formed on a line YY passing through the center C of the main nozzle 1.
[0012]
According to the mixing body M provided with the main nozzle 1, the gas fuel adjusted to a substantially atmospheric chamber state in the secondary decompression chamber 36 of the vaporizer V is the secondary fuel discharge passage 38, the secondary pressure, as in the prior art. The gas fuel is introduced into the passage 1A of the main nozzle 1 through the fuel introduction path 16, and the gas fuel is sucked into the mixer venturi section 11 through the main port 2 and supplied to the engine.
Reference numeral 17 denotes an idle port that opens to the intake passage 10 on the downstream side of the throttle valve 13, and only the gas fuel in the primary decompression chamber 22 is controlled by the primary adjustment screw 33 in the idle port 17. After that, the fuel is supplied through the primary fuel discharge passage 27 and the primary pressure fuel introduction passage 18 and is therefore supplied to the intake passage 10 downstream from the throttle valve 13 through the idle port 17, thereby the engine low throttle valve. Opening operation is performed.
Here, according to the mixing body M according to the present invention,
The gas fuel sucked from the main port 2 to the mixer venturi unit 11 is uniformly and well mixed with the air flowing through the mixer venturi unit 11.
This is due to the following reason.
The main port 2 is formed so as to open toward the mixer venturi unit 11, so that the main port 2 can be opened away from the wall surface of the mixer venturi unit 11, whereby the main port 2 can be opened from the mixer venturi unit 11. That is, the gas fuel sucked in is prevented from flowing along the wall surface of the mixer venturi section 11, and the mixing with the air flowing through the mixer venturi section 11 can be improved.
Further, the main port 2 can be opened to a region of high negative pressure generated in the mixer venturi section 11 by arranging a plurality of the main ports 2 along the longitudinal axis direction ZZ of the main nozzle 1.
According to this, since the high negative pressure generated in the mixer venturi unit 11 can be applied to the main port 2 when the throttle valve 13 is opened from the low opening to the middle to high opening, the mixer venturi unit 11 can eliminate the delay in sucking the gas fuel in the secondary decompression chamber 36, thereby improving the operability of the engine.
Furthermore, if the main port 2 is opened only in the range of 45 degrees to the engine side and 45 degrees to the air cleaner side, the suction of gas fuel from the main port 2 into the mixer venturi section 11 is not hindered. Moreover, the mixing property between the gas fuel sucked into the mixer venturi unit 11 and air can be improved.
That is, when the main port 2 is opened to the air cleaner side in the range of 45 degrees, the air flow from the air cleaner side to the engine side (the air flow from right to left in FIG. 2) A direct collision and entry into the main port 2 to prevent the fuel from being sucked into the mixer venturi 11 from the main port 2 is reduced.
Further, by opening the main port 2 to the engine side in the range of 45 degrees, the gas fuel sucked out from the main port 2 is prevented from being caught in the vortex generated on the back side of the main nozzle on the engine side. The mixing property of the air flowing through the mixer venturi unit 11 and the gas fuel can be improved.
[0013]
Next, a second embodiment of the present invention will be described with reference to FIG.
In addition, the same structure part as FIG. 1 uses the same code | symbol, and abbreviate | omits description.
Reference numeral 4 denotes an annular groove formed in a ring shape inwardly of the mixer venturi section 11, and the upper end 1B and the lower end 1C of the main nozzle 1 shown in FIG. And the opening of the lower end 1 </ b> C face the annular groove portion 4.
Further, the secondary pressure fuel introduction passage 16 is opened in the annular groove portion 4, and the gas fuel having the secondary pressure supplied to the secondary pressure fuel introduction passage 16 is supplied to the main nozzle 1 through the annular groove portion 4. Is done.
By adopting such a structure, it is possible to further improve the characteristics of sucking gas fuel into the mixer venturi section 11.
That is, the distribution of the negative pressure in the mixer venturi section 11 is highest in the central portion from the wall surface of the venturi section 11. A great negative pressure can be applied.
On the other hand, gas fuel is supplied to the upper main port 2A from the upper 4A of the annular groove 4 and gas fuel is supplied to the lower main port 2B from the lower 4B of the annular groove 4.
According to the above, particularly in the lower main port 2B, the gas fuel in the substantially atmospheric pressure state in the lower part 4B of the annular groove part 4 can be sucked into the mixer venturi part 11, so that the gas fuel suction characteristic can be improved.
If gas fuel is supplied into the main nozzle 1 only from the opening of the upper end 1B as in the conventional main nozzle 1, gas fuel in a negative pressure state is supplied to the lower main port 2B, and the main port 2B The differential pressure with respect to is reduced and the suckability is inhibited.
(The reason why gas fuel in a negative pressure state is supplied to the lower main port 2B is that negative pressure flows into the passage 1A of the main nozzle 1 from the upper main port 2A.)
Accordingly, the gas fuel in the atmospheric pressure state can be sucked out from the upper main port 2A where the high negative pressure acts, and the gas fuel in the atmospheric pressure state can be sucked out from the lower main port 2B where the high negative pressure acts. The fuel suction characteristics can be improved.
[0014]
【The invention's effect】
As described above, according to the fuel supply device in the internal combustion engine of the present invention,
The mixer venturi section is arranged across the main nozzle and a plurality of main ports are drilled, and the main port has a cross section perpendicular to the longitudinal axis of the main nozzle and a line perpendicular to the longitudinal axis of the intake passage. As a standard, it opens only in the range of 45 degrees to the engine side and 45 degrees to the air cleaner side. Therefore, when the throttle valve is opened from the low opening to the middle to the high opening, the high negative pressure generated in the mixer venturi section Can act on the main port, the delay in sucking the gas fuel in the secondary decompression chamber to the mixer venturi section 11 can be eliminated, and the operability of the engine can be improved, and the air flowing through the mixer venturi section and the main nozzle The gas fuel sucked from the gas can be mixed uniformly and satisfactorily. On the other hand, only the gas fuel in the primary decompression chamber is supplied to the idle port , whereby the engine is operated with a low throttle valve opening.
[0015]
According to the present invention, an annular groove portion surrounding the mixer venturi portion is provided inside the mixer venturi portion, a secondary pressure fuel introduction passage is opened in the annular groove portion, and both ends of the main nozzle are disposed. The suction characteristics into the mixer venturi can be further improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a fuel supply device for an internal combustion engine according to the present invention.
FIG. 2 is a cross-sectional view taken along the line WW in FIG.
FIG. 3 is a longitudinal sectional view showing another embodiment of the fuel supply device in the internal combustion engine according to the present invention.
FIG. 4 is a longitudinal sectional view showing a conventional fuel supply device.
[Explanation of symbols]
1 Main nozzle 1B, 1C Both ends of main nozzle 2 Main port 4 Annular groove 10 Intake passage 11 Mixer venturi 13 Throttle valve 16 Secondary pressure fuel introduction passage 17 Idle port 22 Primary decompression chamber 36 Secondary decompression chamber M Mixing body V Vaporizer

Claims (2)

The gas fuel from the gas fuel source (T1, T2) is depressurized to a predetermined primary pressure in the primary depressurization chamber (22) and depressurized to a secondary pressure in a substantially atmospheric state in the secondary depressurization chamber (36). Vaporizer (V) to do;
A mixing body (M) in which a main port (2) is opened in a mixer venturi section (11) provided in an intake path (10) penetrating through the interior; the intake path (downstream of the mixer venturi section (11)) ( 10) In a fuel supply device comprising a throttle valve (13) pivotally supported by the mixing body (M) to open and close
In the mixer venturi section (11), a pipe-shaped main nozzle (1) into which the gas fuel in the secondary decompression chamber (36) is introduced is disposed across the main nozzle (1), and the mixer nozzle (1) includes the mixer venturi. A plurality of main ports (2) that open into the portion (11) are opened,
The main port (2) is connected to the longitudinal axis (XX) of the intake passage (10) in a cross section (WW) perpendicular to the longitudinal axis (ZZ) of the main nozzle (1). With reference to the perpendicular line (Y-Y), it opens only in the range of 45 degrees to the engine side and 45 degrees to the air cleaner side,
Fuel in an internal combustion engine, wherein an idle port (17) into which only gas fuel in the primary decompression chamber (22) is introduced is opened in the intake passage (10) downstream of the throttle valve (13). Feeding device.   An annular groove portion (4) surrounding the mixer venturi portion (11) is provided inside the mixer venturi portion (11), and the secondary groove connected to the secondary decompression chamber (36) is provided in the annular groove portion (4). 2. The fuel supply device for an internal combustion engine according to claim 1, wherein the pressurized fuel introduction passage (16) is opened and both ends (1B, 1C) of the main nozzle (1) are opened.

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