JP4096536B2 - Vaporizer for internal combustion engines - 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 gas fuel in the gas fuel source is supplied to a predetermined one in a primary decompression chamber. The present invention relates to a vaporizer that depressurizes to a secondary pressure and depressurizes the secondary pressure to a secondary pressure of substantially atmospheric pressure in a secondary decompression chamber.
[0002]
[Prior art]
A conventional vaporizer V will be described with reference to FIG.
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 which is connected to the slow lock valve via a connecting rod 29A and applies an opening / closing operation force to the slow lock valve 28. A slow lock pressure receiving chamber 30 defined by the slow lock diaphragm 29 is provided. A slow lock spring 31 that presses the slow lock diaphragm 29 rightward in FIG.
In other words, it can be said that the slow lock spring 31 urges the slow lock valve 28 to close the primary fuel discharge passage 27.
Then, the negative pressure generated by the operation of the engine is introduced into the slow lock pressure receiving chamber 30 through the negative pressure introduction path 32.
In this example, the upstream side of the negative pressure introduction path 32 is connected to an intake path of a mixing body described later.
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 has a tapered needle valve portion 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 using liquefied petroleum gas (hereinafter referred to as LPG), 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.
M is a mixing body that is supplied with the gas fuel from the vaporizer and supplies an air / gas fuel mixture to the engine via an intake pipe (not shown).
The mixing body M is bored through the intake passage 40 and a mixer venturi 41 is formed upstream thereof.
The intake passage is controlled to be opened and closed by a throttle valve 43 attached to a throttle valve shaft 42 rotatably supported by a mixing body M, while a plurality of main ports 44 are formed in the mixer venturi section 41. Therefore, the main port 44 is connected to the secondary pressure fuel introduction passage 46 via an annular groove 45 formed so as to surround the mixer venturi 41.
Reference numeral 47 denotes an idle port that opens to the intake passage 40A on the downstream side of the throttle valve 43, to which a primary pressure fuel introduction passage 48 is communicated.
The secondary pressure fuel introduction path is connected to the secondary fuel discharge path 38 of the vaporizer V, and the primary pressure fuel introduction path 48 is connected to the primary fuel discharge path 27.
[0003]
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 and 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. ^The pressure 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 side, 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 can be 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. .
When the engine is started, a negative pressure is generated in the intake passage 40A on the downstream side of the throttle valve 43 of the mixing body M. This negative pressure is generated in the slow lock pressure receiving chamber 30 via the negative pressure introduction passage 32. To be introduced. According to this, the slow lock diaphragm 29 moves to the left in the figure against the spring force of the slow lock spring 31 (in other words, moves to the slow lock pressure receiving chamber 30 side), and the slow lock diaphragm 29 moves to the left. Is transmitted to the slow lock valve 28 by the connecting rod 29A, and the slow lock valve 28 opens the primary fuel discharge passage 27.
According to the above, the amount of the gas fuel in the primary decompression chamber 22 having the primary pressure is controlled by the primary adjustment screw 33, and this gas fuel is supplied to the primary fuel discharge passage 27 and the primary pressure fuel introduction passage 48. , Are supplied to the idle port 17, whereby the engine is started and the low opening operation is performed.
[0004]
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 44 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.
Then, when the throttle valve 43 opens the intake passage 40 to a medium opening degree and a high opening degree, a high negative pressure is generated in the mixer venturi section 41 according to the throttle valve opening degree.
This negative pressure acts on the secondary decompression chamber 36 via the main port 44, the annular groove 45, the secondary pressure fuel introduction passage 46, and the secondary fuel discharge passage 38, and is maintained in the secondary decompression chamber 36. The gas fuel in the state is sucked out to the mixer venturi section 41 through the main port 44, whereby the inside of the throttle valve 43 and the high opening operation are performed.
[0005]
[Problems to be solved by the invention]
According to such a conventional vaporizer, the operability of the engine may be hindered during a snap operation in which the throttle valve is continuously opened and closed from a low opening to a high opening.
This is due to the following reason.
When the throttle valve 43 is at a low opening, a large negative pressure is generated in the intake passage 40 </ b> A on the downstream side of the throttle valve 43, and this large negative pressure is passed through the negative pressure introduction passage 32 to the slow lock pressure receiving chamber 30. Introduced in.
According to the above, the slow lock diaphragm 29 is displaced toward the slow lock pressure receiving chamber 30 against the spring force of the slow lock spring 31. According to this, the slow lock valve 28 opens the primary fuel discharge passage 27, and 1 Gas fuel having a primary pressure in the secondary decompression chamber 22 is supplied to the intake passage 40 of the mixing body M through the idle port 47, whereby the throttle valve 43 is operated at a low opening.
When the throttle valve 43 is suddenly opened from the low opening state of the throttle valve 43, the negative pressure in the intake passage 40 temporarily decreases (approaches atmospheric pressure). When the pressure is introduced into the slow lock pressure receiving chamber 30 through the negative pressure introduction path 32, the slow lock diaphragm 29 is moved to the secondary pressure reducing chamber 36 side (right side in the figure) by the spring force of the slow lock spring 31. To do.
According to the above, the slow lock valve 28 moves to the right in the drawing in synchronization with the slow lock diaphragm 29, closes the primary fuel discharge passage 27, and has a primary pressure from the idle port 47 into the intake passage 40. The supply of gas fuel will be temporarily stopped.
Then, when a snap operation is performed in which the throttle valve is continuously opened and closed, the concentration of the gas fuel mixture flowing in the intake passage 40 is diluted, and the engine speed falls below a predetermined speed. And there is a risk of the engine stopping.
[0006]
The present invention has been made in view of the above problems, and in the snap operation in which the throttle valve is continuously opened and closed from the low opening to the high opening, the supply of the gas fuel is interrupted, and the gas fuel mixture It is an object of the present invention to provide a vaporizer for an internal combustion engine that can obtain stable engine operation without being diluted in concentration.
[0007]
[Means for achieving the object]
In order to achieve the above object, the vaporizer for an internal combustion engine according to the present invention reduces the gas fuel in the gas fuel source to a predetermined primary pressure in the primary decompression chamber and is substantially large in the secondary decompression chamber. Reduced to a secondary pressure in the atmospheric state,
A slow lock valve that opens and closes the passage according to the negative pressure in the intake passage is disposed in the primary fuel discharge passage that opens from the primary decompression chamber toward the outside, and an opening / closing operation force is applied to the slow lock valve. In a vaporizer in which a slow lock pressure receiving chamber and an intake passage separated by a slow lock diaphragm are connected by a negative pressure introduction passage;
The pressure control valve includes an upstream chamber formed facing one side of the partition wall, a downstream chamber formed facing the other side of the partition wall,
A valve hole communicating the upstream chamber and the downstream chamber, and a bypass passage communicating the upstream chamber and the downstream chamber ,
A thin plate-like control plate is arranged on one end face of the partition wall on the upstream chamber side, and a U-shaped tongue piece is formed on the control plate, so that the negative pressure generated in the intake passage is constant. opening the valve hole in the above negative pressure value, thereby forming a check valve for closing the valve hole in less negative pressure, it is disposed in the bypass passage to the control board, and a control orifice which always communicates with a predetermined opening The upstream chamber is communicated with the intake passage via the upstream negative pressure introduction passage, and the downstream chamber is communicated with the slow lock pressure receiving chamber via the downstream negative pressure introduction passage.
[0008]
[Action]
At a low opening of the throttle valve, a large negative pressure generated in the intake passage acts on the check valve of the pressure control valve, and the check valve keeps the valve hole open.
Therefore, a large negative pressure in the intake passage is introduced into the slow lock pressure receiving chamber through the valve hole and the downstream negative pressure introduction passage, whereby the slow lock valve keeps the primary fuel discharge passage open and holds the primary fuel discharge passage. Gas fuel having a primary pressure in the decompression chamber is supplied into the intake passage through the primary fuel discharge passage and the idle port.
On the other hand, if the throttle valve is suddenly opened from the low opening state to the high opening degree, the negative pressure in the intake passage is greatly reduced. When this reduced negative pressure acts on the check valve, the check valve The valve immediately closes the valve hole.
According to the above, a large negative pressure is maintained in the slow lock pressure receiving chamber, and the slow lock valve still keeps the primary fuel discharge passage open.
Therefore, when a snap operation is performed in which the throttle valve is continuously opened and closed, the supply of gas fuel from the primary fuel discharge passage is not temporarily stopped, and the operation of the engine is stabilized. Can be done.
On the other hand, a part of the large negative pressure in the slow lock pressure receiving chamber is slightly leaked from the downstream chamber to the upstream chamber through the bypass passage and the control orifice, so that the large negative pressure in the slow lock pressure receiving chamber gradually increases. Since it is weakened, it is possible to achieve an appropriate mixture concentration.
[0009]
【Example】
Hereinafter, an embodiment of a vaporizer 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 showing an embodiment of a vaporizer for an internal combustion engine according to the present invention.
FIG. 2 is a longitudinal sectional view of a pressure control valve used in FIG.
3 is a longitudinal sectional view taken along line AA in FIG.
The vaporizer according to the present invention is obtained by adding a pressure control valve P to a conventional vaporizer.
Note that the same components as those in the prior art are denoted by the same reference numerals and description thereof is omitted.
The pressure control valve P consists of the following. (Particularly described with reference to FIGS. 2 and 3)
Reference numeral 1 denotes a partition wall body having a first side end surface 1A and a second side end surface 1B, and a valve hole 2 and a bypass passage 3 are drilled through from the first side end surface 1A to the second side end surface 1B.
The valve hole 2 and the bypass passage 3 are formed in parallel in the partition wall body 1, and the valve hole 2 and the bypass passage 3 are not in direct communication with each other.
4 is disposed on one end face 1A of the partition wall body 1. It is a bottomed cup-shaped upstream cover having a recess 4A, and an upstream passage 4B opens in the recess 4A.
Reference numeral 5 denotes a thin plate-like control plate disposed on one end face 1A of the partition wall body 1. The control plate 5 includes a check valve 6 that can open and close the valve hole 1 of the partition wall body 1, and a bypass. A control orifice 7 is formed facing the passage 3.
Specifically, the control plate 5 is formed of a thin stainless steel material having a thickness of, for example, about 0.5 millimeters, the check valve 6 is formed of a U-shaped tongue piece, and the control orifice 7 is It is formed with minute holes.
Note that the valve opening characteristics of the check valve 6 and the diameter of the control orifice 7 are determined by a conformity test for each engine.
8 is arrange | positioned on the other side end surface 1B of the partition wall body 1. FIG. It is a bottomed cup-shaped downstream cover having a recess 8A, and a downstream passage 8B opens in the recess 8A.
And the control board 5 and the upstream cover 4 are arrange | positioned on the one side end surface 1A of the said partition wall 1, and the downstream cover 8 is arrange | positioned on the other side end surface 1B, In this state, the upstream cover 4, the control board 5, and the partition The wall body 1 and the downstream cover 8 are assembled together by screws 9.
According to the above, the upstream chamber PA is formed by the one end face 1A of the partition wall body 1 and the recess 4A of the upstream cover 4, and the downstream chamber PB is formed by the other end face 1B and the recess 8A of the downstream cover 8, The upstream passage 4B opens in the upstream chamber PA, and the downstream passage 8B opens in the downstream chamber PB.
Further, the outer periphery of the control plate 5 is fixedly supported by the one end face 1A of the partition wall body 1 and the upstream cover 4. At this time, the check valve 6 is disposed facing the valve hole 2 and is controlled. The orifice 7 is arranged facing the bypass passage 3.
The control plate 5 is disposed in airtight contact with the one side surface 1A of the partition wall body 1, and description of a seal ring, adhesion, and the like for maintaining the airtightness is omitted.
Therefore, the valve hole 2 and the upstream chamber PA are controlled to open / close only with the check valve 6, and the bypass passage 3 is connected to the upstream chamber PA only with the control orifice 7. The periphery of the control plate 5 and the check valve 6 does not communicate with the valve hole 2, and the periphery of the control orifice 7 does not communicate with the bypass passage 3.
Reference numeral 4C denotes a pressing portion for pressing the base portion of the check valve 6 against the one end face 1A of the partition wall 1.
[0010]
The upstream passage 4B of the pressure control valve P is connected to the upstream negative pressure introduction passage 32A toward the intake passage 40A, and the downstream passage 8B is connected to the downstream negative pressure introduction passage 32B toward the slow lock pressure receiving chamber 30. The This is shown in FIG.
[0011]
The vaporizer according to the present invention performs the following actions.
When the throttle valve 43 is operated at a constant opening when the throttle valve 43 is at a low opening, a large negative pressure exceeding a certain negative pressure value is generated in the intake passage 40, and this large negative pressure is the upstream negative pressure introduction passage. 32A is introduced into the upstream chamber PA of the pressure control valve P from the upstream passage 4B.
When this large negative pressure acts on the check valve 6 in the upstream chamber PA, the reverse valve 6 opens the valve hole 2, and the large negative pressure in the upstream chamber PA is the valve hole 2. The vaporizer V is introduced into the slow lock pressure receiving chamber 30 through the downstream chamber PB, the downstream passage 8B, and the downstream negative pressure introduction passage 32B.
According to this large negative pressure acting on the slow lock pressure receiving chamber 30, the slow lock diaphragm 29 moves to the left in the figure against the spring force of the slow lock spring 11, thereby causing the slow lock valve 28 to move. The primary fuel discharge passage 27 is held open.
According to the above, the gas fuel having the primary pressure in the primary decompression chamber 22 is supplied into the intake passage 40 via the primary fuel discharge passage 27, the primary pressure fuel introduction passage 48, and the idle port 47, and thus the throttle valve. 43 is operated at a low opening.
In the throttle valve 43, the high opening operation is performed in the same manner as in the prior art, and the description thereof is omitted.
[0012]
Next, a snap operation in which the throttle valve 43 is continuously opened and closed from a low opening degree of the throttle valve 43 will be described.
When the throttle valve 43 opens the intake passage 40 more rapidly than the low opening degree, the air flow flowing in the intake passage 40 becomes slow, and the negative pressure is greatly reduced (approaching atmospheric pressure), and becomes a certain negative pressure value or less. A negative pressure equal to or lower than the certain negative pressure value reaches the upstream chamber PA of the pressure control valve P via the upstream negative pressure introduction passage 32A.
According to this, the check valve 6 in the upstream chamber PA immediately closes the valve hole 2 due to a decrease in negative pressure, so that negative pressure below a certain negative pressure value does not reach the slow lock pressure receiving chamber 30, The negative pressure in the slow lock pressure receiving chamber 30 is maintained in a high negative pressure state during the low opening operation of the throttle valve 43, and the negative pressure is prevented from decreasing.
Accordingly, since the slow lock valve 28 can continuously keep the primary fuel discharge passage 27 open, the gas fuel having the primary pressure in the primary decompression chamber 22 is continuously supplied into the intake passage 40 via the idle port 47. Can supply.
On the other hand, when the throttle valve 43 is closed from the open state to the low opening degree by the snap operation, the intake passage 40A on the downstream side of the throttle valve 43 has a large value equal to or greater than a certain negative pressure value. When such a large negative pressure acts on the check valve 6 of the pressure control valve P, the check valve 6 in the closed state opens the valve hole 2 again and becomes large. The negative pressure acts on the slow lock pressure receiving chamber 30 again, and the slow lock valve 28 keeps the primary fuel discharge passage 27 open as described above.
[0013]
According to the above, when the throttle valve 43 is in the low opening state, the slow lock pressure receiving chamber 30 is subjected to a large negative pressure greater than a certain negative pressure value in the intake passage 40A on the downstream side of the throttle valve 43, causing the slow lock. When the valve 28 keeps the primary fuel discharge passage 27 open and the throttle valve 43 is suddenly opened from the low opening state to the high opening state, it is in the intake passage 40A on the downstream side of the throttle valve 43. The check valve 6 immediately closes the valve hole 2 to maintain the high negative pressure introduced into the slow lock pressure receiving chamber 30 in the above state even if the negative pressure of the valve decreases below a certain negative pressure value. As a result, the slow lock valve 28 can still keep the primary fuel discharge passage 27 open, and when the throttle valve 43 is returned from the high opening state to the low opening state in the throttle valve, the intake passage 40A. A negative pressure exceeding a certain negative pressure value is generated again, and this negative pressure opens the check valve 6. Was introduced from the valve hole 2 to the slow locking pressure chamber, the slow lock valve 28 can be opened holds the primary fuel discharge passage 27.
[0014]
As described above, according to the vaporizer according to the present invention, the throttle valve 43 is opened from the low opening to the middle to high opening, and the snap valve 43 is returned to the low opening again. Even if the negative pressure drops below a certain negative pressure value, a negative pressure equal to or higher than the certain negative pressure value can always be secured in the slow lock pressure receiving chamber 30 and continuously from the idle port 47 during the snap operation. Gas fuel can be supplied stably, and the operability of the engine is not hindered.
[0015]
The pressure control valve P is provided with a bypass passage 3 that bypasses the valve hole 2 and connects the upstream chamber PA and the downstream chamber PB, and the bypass passage 3 is provided with a control orifice 7, which is necessary. As described above, the negative pressure in the slow lock pressure receiving chamber 30 is not maintained in a large negative pressure state.
For example, when the engine is stopped after a snap operation, a large negative pressure is maintained in the slow lock pressure receiving chamber 30 (this is an operation often performed in a two-wheeled vehicle). The secondary fuel discharge passage 27 is held open, and the fuel having the primary pressure is still supplied from the idle port 47 from the primary fuel discharge passage 27 even when the engine is stopped.
On the other hand, in the vaporizer of the present invention, the control orifice 7 is disposed in the bypass passage 3, and a large negative pressure held in the slow lock pressure receiving chamber 30 is gradually increased to the atmosphere side through the control orifice 7. The negative pressure in the slow lock pressure receiving chamber 30 can be reduced after a predetermined time has elapsed, and the primary fuel discharge passage 27 is closed by the slow lock valve 28, so that the gas fuel having the primary pressure is discharged into the idle port 47. It will not continue to be supplied.
The hole diameter of the control orifice 7 is optimally determined from the pressure holding characteristics in the slow lock pressure receiving chamber 30 during the snap operation and the negative pressure release characteristics in the slow lock pressure receiving chamber 30 when the engine is stopped.
Further, the structure of the check valve and the control orifice is not limited to the above embodiment.
[0016]
【The invention's effect】
As described above, according to the vaporizer for an internal combustion engine according to the present invention, the gas fuel in the gas fuel source is decompressed to a predetermined primary pressure in the primary decompression chamber and is substantially at atmospheric pressure in the secondary decompression chamber. To a secondary pressure of
A slow lock valve that opens and closes the passage according to the negative pressure in the intake passage is disposed in the primary fuel discharge passage that opens from the primary decompression chamber toward the outside, and an opening / closing operation force is applied to the slow lock valve. In the vaporizer in which the slow lock pressure receiving chamber and the intake passage, which are separated by the slow lock diaphragm, are connected via the negative pressure introduction passage;
The pressure control valve includes an upstream chamber formed facing one side of the partition wall, a downstream chamber formed facing the other side of the partition wall,
A valve hole communicating with the upstream chamber and the downstream chamber; a bypass passage communicating between the upstream chamber and the downstream chamber; and a valve hole is opened when the negative pressure generated in the intake passage is equal to or greater than a certain negative pressure value. A check valve that closes the valve hole with a negative pressure, and a control orifice that is disposed in the bypass passage and always communicates with a constant opening, and communicates the upstream chamber with the intake passage through the upstream negative pressure introduction passage. At the same time, the downstream chamber was connected to the slow lock pressure receiving chamber via the downstream negative pressure introduction path.
During the snap operation of the engine, stable gas fuel can be supplied, good engine operability can be obtained, and unnecessary gas fuel supply can be stopped and the gas mixture can be stopped when the engine is stopped immediately after the snap operation, etc. It can be suppressed that the concentration tends to increase.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a vaporizer for an internal combustion engine according to the present invention.
FIG. 2 is a longitudinal sectional view of a pressure control valve used in FIG.
FIG. 3 is a longitudinal sectional view taken along line AA in FIG.
FIG. 4 is a longitudinal sectional view showing a conventional vaporizer for an internal combustion engine.
[Explanation of symbols]
2 Valve hole 3 Bypass passage 6 Check valve 7 Control orifice 22 Primary decompression chamber 27 Primary fuel discharge passage 28 Slow lock valve 27 Slow lock diaphragm 30 Slow lock pressure receiving chamber 32 Negative pressure introduction passage 36 Secondary decompression chamber P Pressure control valve

Claims (1)

The gas fuel in the gas fuel source 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). The primary fuel discharge passage (27) that opens from the chamber (22) toward the outside is provided with a slow lock valve (28) that opens and closes the passage according to the negative pressure in the intake passage, and the slow lock valve ( 28) in a vaporizer in which a slow lock pressure receiving chamber (30) and an intake passage (40) separated by a slow lock diaphragm (29) for applying an opening / closing operation force to 28) are communicated by a negative pressure introduction passage (32);
The pressure control valve (P) is formed facing an upstream chamber (PA) formed facing one side (1A) of the partition wall (1) and facing the other side (1B) of the partition wall (1). Downstream chamber (PB)
A valve hole (2) communicating the upstream chamber (PA) and the downstream chamber (PB), and a bypass passage (3) communicating the upstream chamber (PA) and the downstream chamber (PB) ,
A thin plate-shaped control plate (5) is disposed on one end surface (1A) on the upstream chamber (PA) side of the partition wall (1), and a U-shaped tongue piece is provided on the control plate (5). By forming the check valve, the valve hole (2) is opened when the negative pressure generated in the intake passage (40A) is equal to or higher than a certain negative pressure value, and the valve hole (2) is closed with a negative pressure lower than that ( 6) and a control orifice (7) which is arranged in the bypass passage (3) in the control plate (5) and is always in communication with a constant opening, and introduces upstream negative pressure into the upstream chamber (PA). It connects to the intake passage (40A) via the passage (32A) and communicates the downstream chamber (PB) to the slow lock pressure receiving chamber (30) via the downstream negative pressure introduction passage (32B). Vaporizer for internal combustion engines.

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