JP2011236789A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts while maintaining responsiveness and control accuracy in an auxiliary chamber type gas engine provided with an auxiliary chamber connected to a combustion chamber (main chamber).SOLUTION: In the auxiliary chamber type gas engine 10 provided with an auxiliary chamber 15 connected to a main chamber 14 has, for each combustion room, a fuel supply device 20 for supplying fuel, a first fuel supply passage 23 for connecting the fuel supply device 20 and an intake pipe 16, a second fuel supply passage 24 for connecting the fuel supply device 20 and the auxiliary chamber 15, and a switching means 22 disposed at the fuel supply device 20 for switching communication between the fuel supply device 20 and the first fuel supply passage 23 or the second fuel supply passage 24, the switching means 22 is composed of a switching chamber 30 and a piston 40 that is slidably inserted into the switching chamber 30, and switches communication between the fuel supply device 20 and the first fuel supply passage 23 or the second fuel supply passage 24 by the slide of the piston 40 in the switching chamber 30.

Description

  The present invention relates to a sub-chamber combustion type gas engine using a gas fuel such as natural gas, and more particularly to a fuel supply device that supplies gas fuel to a combustion chamber and a sub-chamber.

  In a gas engine using natural gas as fuel, for example, in order to reduce fuel consumption and NOx, combustion is performed in a lean state where the air-fuel ratio of the air-fuel mixture in the combustion chamber is leaner than the stoichiometric air-fuel ratio. However, the combustion in the lean state is unstable in ignitability compared with the combustion by the stoichiometric air-fuel ratio, and sufficient output may not be obtained. Accordingly, a combustion chamber is divided into a main chamber for obtaining output and a sub chamber connected to the main chamber, and a sub chamber type gas engine is provided which improves the ignitability by changing the ratio of fuel supplied to each. Yes. In the sub-chamber gas engine, the sub-chamber filled with the fuel-rich mixture is ignited, and the ignited air-fuel mixture in the sub-chamber is ejected into the main chamber, thereby igniting the lean air-fuel mixture in the main chamber. Raised.

In the conventional sub-chamber type gas engine described in Patent Document 1, in addition to the gas mixer 23 installed in the intake passage for supplying fuel to the main chamber, a manual shut-off valve 31 for controlling the fuel supplied to the sub-chamber. Is provided. Further, a check valve is provided downstream of the manual shut-off valve 31 to prevent the backflow of the gas fuel accompanying the pressure increase in the sub chamber. This makes it possible to control the amount of fuel supplied to the main chamber and the sub chamber and the supply timing.
Further, in the conventional sub-chamber gas engine described in Patent Document 2, the sub-fuel that supplies fuel to the sub chamber downstream of the gas control valve 14 that opens and closes the main fuel supply passage that supplies fuel to the intake passage. A branch portion of the supply path is provided. The sub fuel supply passage for supplying fuel to the sub chamber has a check valve for preventing the back flow of the gas fuel accompanying the pressure increase in the sub chamber, and an opening adjustment for changing the gas flow rate of the sub fuel supply passage. A valve is provided. As a result, the number of control valves for controlling the supply of fuel can be reduced.

Japanese Patent Laid-Open No. 5-113148 JP 2009-299592 A

  In the sub-chamber type gas engine described in Patent Document 1, it is possible to control the fuel amount and timing supplied to the main chamber and the sub-chamber, but it is necessary to increase the number of parts in order to control. In the sub-chamber type gas engine described in Patent Document 2, the number of components for controlling the fuel can be reduced, but the amount of fuel supplied to the main chamber side and the sub-chamber side supplied simultaneously is controlled by one control valve. Therefore, it is difficult to accurately control the amount and timing of fuel supplied to each chamber. An object of the present invention is to reduce the number of parts while maintaining responsiveness and control accuracy in a sub-chamber type gas engine provided with a sub-chamber connected to a combustion chamber.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a sub-chamber type gas engine including a sub-chamber connected to the main combustion chamber, a fuel supply section for supplying fuel, and a fuel supply A first fuel supply passage that connects the fuel supply portion and the intake pipe, a second fuel supply passage that connects the fuel supply portion and the sub chamber, a fuel supply portion, and a first fuel supply passage that is disposed in the fuel supply portion Or a switching means for switching the communication with the second fuel supply passage for each combustion chamber, the switching means comprising a switching chamber and a valve body slidably inserted into the switching chamber, Is configured to switch communication between the fuel supply unit and the first fuel supply passage or the second fuel supply passage by sliding in the switching chamber.
According to the first aspect of the present invention, the fuel supplied from the fuel supply unit by the valve body sliding in the switching chamber is the second fuel connected to the first intake passage or the sub chamber connected to the intake pipe. It is possible to switch to one of the supply passages, to reduce the number of parts, and to accurately supply the fuel amount aimed at either the intake pipe or the sub chamber.
The intake pipe is a passage through which fresh air flowing into the combustion chamber flows, and includes an intake passage and an intake port.

According to a second aspect of the present invention, the valve element slides in the switching chamber according to the pressure in the sub chamber.
According to the second aspect of the present invention, since the valve body slides in the switching chamber in accordance with the pressure in the sub chamber, the fuel can be accurately controlled by either the intake pipe or the sub chamber based on the state of the sub chamber. Can be supplied.

According to the third aspect of the present invention, the valve body is formed in a piston shape, is formed by one pressure receiving surface of the valve body and the switching chamber, and is connected to the fuel supply unit, and the valve body. The second pressure receiving surface and the switching chamber are connected, and the second chamber to which the second fuel supply passage is connected is communicated with one pressure receiving surface of the valve body forming the first chamber and the valve body sliding surface. A valve body passage is provided, the first fuel supply passage is formed at a position where the valve body passage and the first fuel supply passage communicate with each other in a state where the volume of the first chamber is minimized, and the valve body is in the second chamber. The valve body passage and the second chamber communicate with each other in a state where the volume of the valve is minimized.
According to the third aspect of the present invention, the pressure of the intake pipe or the sub chamber when communicating with the fuel supply unit is low, and the fuel can be supplied efficiently.

According to a fourth aspect of the present invention, the area of the valve body pressure receiving surface on the second chamber side is larger than that of the valve body pressure receiving surface on the first chamber side.
In this invention of Claim 4, even if the pressure of a 1st chamber and a 2nd chamber is the same, it becomes possible to move a valve body to arbitrary directions, and can switch a channel | path easily. .

The present invention described in claim 5 is characterized in that first valve body urging means for urging the valve body in a direction in which the volume of the second chamber decreases is provided.
In this invention of Claim 5, even if the pressure concerning the pressure receiving surface of a valve body is the same, it becomes possible to move a valve body to arbitrary directions, and can switch a path | pass easily.

  The present invention has an excellent effect that the number of parts can be reduced while maintaining responsiveness and control accuracy in a sub-chamber gas engine having a sub-chamber connected to the combustion chamber with a simple configuration. .

1 is a schematic view of a sub-chamber gas engine according to a first embodiment of the present invention. It is a figure of a switching means similarly. It is a figure of a switching means similarly. It is a conceptual diagram which similarly shows the effect | action of a switching means, and fuel supply timing. It is a figure of the switching means which concerns on the 2nd Embodiment of this invention. It is a figure of a switching means similarly. It is a figure of the switching means which concerns on other embodiment.

(First embodiment)
Hereinafter, the sub-chamber type gas engine 10 according to the first embodiment will be described with reference to FIGS. 1 to 4.
FIG. 1 shows a configuration of a sub-chamber gas engine 10 according to the first embodiment. The sub-chamber gas engine 10 is an internal combustion engine that is driven by using gas fuel such as natural gas as fuel. Although only one combustion chamber is illustrated in FIG. 1, the sub-chamber gas engine 10 includes a plurality of combustion chambers. The combustion chamber of the sub-chamber type gas engine 10 is formed in the cylinder head 11, which is a main combustion chamber composed of a cylinder block 11, a cylinder head 12, a combustion chamber piston 13, an unillustrated intake valve and exhaust valve, and the cylinder head 12. The sub chamber 15 is configured. The volume of the main chamber 14 varies as the combustion chamber piston 13 reciprocates along the side wall of the cylinder block 11. The cylinder head 12 is formed with an intake port 16 as an intake pipe for supplying fresh air to the main chamber 14 and an exhaust port 17 for discharging burned gas from the main chamber 14 as exhaust gas.

An unillustrated intake valve and exhaust valve are disposed at the boundary between the intake port 16 and the main chamber 14 and at the boundary between the exhaust port 17 and the main chamber 14. An intake valve and an exhaust valve are reciprocated by an intake cam and an exhaust cam (not shown) that are attached to the upper part of the cylinder head 12 and rotate in conjunction with the rotation of a crankshaft (not shown). 17 is opened and closed. The opening / closing timing of the intake valve and the exhaust valve may be provided so as to be controllable by providing the intake cam and the exhaust cam with an existing valve timing mechanism.
The cylinder head 12 is provided with a fuel supply device 20 as a fuel supply unit that supplies fuel to the intake port 16 and the sub chamber 15.

  The sub chamber 15 is formed on a wall surface facing the combustion chamber piston 13 in the cylinder head 12 and is disposed in the vicinity of the main chamber 14. The wall surface separating the main chamber and the sub chamber is formed in a dome shape projecting toward the main chamber side, and the main chamber 14 and the sub chamber 15 are formed by providing a plurality of jet outlets 18 on the dome wall surface. It is communicated. Further, a spark plug 19 is disposed on the wall surface of the sub chamber 15 opposite to the dome-shaped wall surface, and can be ignited at an arbitrary timing by being connected to an ECU 52 described later.

  The fuel supply device 20 is connected to an injector 21 capable of supplying gas fuel from a gas fuel storage means (not shown), an injector 21 and a passage 25, and a switching chamber 30 to which gas fuel is supplied from the injector 21, It is comprised from the switching means 22 which consists of piston 40 as a valve body arrange | positioned so that sliding is possible. The fuel supply device 20 is connected to a first fuel supply passage 23 whose other end is connected to the intake port 16 and a second fuel supply passage 24 whose other end is connected to the sub chamber 15. Yes. The connection port of the first fuel supply passage 23 connected to the intake port 16 disturbs the flow of intake air flowing through the intake port 16 when the gas fuel flowing through the first fuel supply passage 23 flows into the intake port 16. Is arranged so that there is no.

As shown in FIGS. 2 and 3, the switching chamber 30 constituting the switching means 22 includes a first switching chamber 31, a second switching chamber 32, a third switching chamber 33, and a first switching that are each formed in a cylindrical shape. The switching chamber communication passage 34 communicates the chamber and the third switching chamber. In the following description of the switching chamber and the piston, for convenience of explanation using the drawings, a description that means the vertical direction is used, but this is the vertical direction in the drawing, which is different from the vertical direction that means the vertical direction. May be.
The switching chamber 30 has a shape in which the first switching chamber 31, the second switching chamber 32, and the third switching chamber 33 are stacked in the vertical direction so that the center lines of the respective cylinders overlap, The diameter is set smaller than the diameter of the second switching chamber 32. The diameter of the third switching chamber 33 is set smaller than the diameter of the second switching chamber 32 and larger than the diameter of the first switching chamber 31.

The lower surface of the first switching chamber 31 and the second switching chamber upper surface 321, and the second switching chamber lower surface 322 and the upper surface of the third switching chamber 33 are directly connected to each other.
A passage 25 connected to the injector 21 is connected to the upper surface 311 of the first switching chamber. The first fuel supply passage 23 is connected to the first switching chamber side surface 312. Similarly, on the side surface 312 of the first switching chamber, a switching chamber communication passage 34 connected to the third switching chamber 33 is connected below the first fuel supply passage 23.
The second fuel supply passage 24 is connected to the lower surface 331 of the third switching chamber. A switching chamber communication path 34 connected to the first switching chamber 31 is connected to the third switching chamber side surface 332.

  The piston 40 has a diameter substantially equal to the diameter of the first switching chamber 31 and has a diameter substantially equal to the second switching chamber 32 and a small diameter portion 41 slidably inserted into the first switching chamber 31. And a large-diameter portion 42 that is slidably inserted. Further, the piston 40 is formed with an in-piston passage 43 (valve body passage) that communicates the small diameter portion upper surface 411 (one pressure receiving surface) and the small diameter portion side surface 412 (valve body sliding surface). The length from the upper surface 411 of the small-diameter portion of the piston 40 to the lower surface 422 of the large-diameter portion is set to be shorter than the length from the upper surface 311 of the first switching chamber to the lower surface 322 of the second switching chamber. The length is set smaller than the length of the second switching chamber 32. Accordingly, the piston 40 can slide in the first switching chamber 31 and the second switching chamber 32 in a state where the piston 40 is inserted into the switching chamber 30.

  When the piston 40 is inserted into the switching chamber 30, the first spring 51 as the first valve body urging means is disposed between the second switching chamber upper surface 321 and the large-diameter portion upper surface 421. As a result, the piston is always biased downward.

  As shown in FIG. 2, in a state where the piston 40 is inserted into the switching chamber 30, the first switching chamber 31 and the small-diameter portion upper surface 411 (one pressure receiving surface) constitute the first chamber 26, and the second switching chamber 32. The second chamber 27 is configured by the third switching chamber 33 and the large-diameter portion lower surface 422 (the other pressure receiving surface). In the state where the piston 40 is moved upward as much as shown in FIG. 2, that is, in the state where the volume of the first chamber 26 is minimized, the connection port of the first fuel supply passage 23 in the switching chamber 30; The position in the vertical direction of the small-diameter side surface 412 and the communication port of the in-piston passage 43 is set to be the same position.

  Further, as shown in FIG. 3, when the piston 40 is moved downward as much as possible, that is, in a state where the volume of the second chamber 27 is minimized, the switching chamber communication path 34 formed in the first switching chamber side surface 312. And the position in the vertical direction of the small-diameter side surface 412 and the communication port of the in-piston passage 43 are set to be the same position. A convex protrusion 313 (described only in FIG. 2) is formed below the wall surface of the first switching chamber side surface 312 facing the wall surface where the connection port of the first fuel supply passage 23 is formed. A concave notch 413 (described only in FIG. 2) extending in the vertical direction is formed in one direction on the small-diameter side surface 412 of the piston 40. When the piston 40 is inserted into the switching chamber 30, the rotation of the piston 40 relative to the switching chamber 30 can be prevented by inserting the protruding portion 313 and the cutout portion 413 in alignment. Thus, the direction of the communication port of the in-piston passage 43 on the small diameter side surface 412 is always a straight line connecting the connection port of the first fuel supply passage 23 and the communication port of the switching chamber communication channel 34 on the first switching chamber side surface 312. Piston 40 can be arrange | positioned so that it may contact | connect.

  As shown in FIG. 1, the sub-chamber gas engine 10 is provided with a rotation speed sensor 53 for detecting the engine speed and an accelerator opening sensor 54 for detecting the accelerator opening. The rotational speed sensor 53 and the accelerator opening sensor 54 may be known sensors. The sub-chamber gas engine 10 includes an ECU 52 to which values of the rotation speed sensor 53 and the accelerator opening sensor 54 are input. The ECU 52 is connected to the injector 21 and the spark plug 19 and controls the fuel supply timing, the fuel supply time, and the ignition timing of the spark plug 19 by the injector 21 according to the output value obtained from the input value.

Next, the operation of the switching means 22 configured as described above will be described with reference to FIGS.
As shown in FIG. 3, when no pressure is applied to the upper surface 411 and the lower surface 422 of the large diameter portion of the piston 40, the piston 40 moves downward as much as possible by the biasing force of the first spring 51. In other words, the state in which the volume of the second chamber 27 is minimized is maintained. In this state, the position of the connection port of the switching chamber communication path 34 disposed on the first switching chamber side surface 312 and the communication port of the piston inner passage 43 on the small diameter side surface 412 coincide with each other. The communication port of the inner passage 43 is communicated.

  When pressure is applied to the second chamber 27 from a state in which no pressure is applied to the small diameter upper surface 411 and the large diameter lower surface 422 of the piston 40, the large diameter lower surface 422 receives pressure, and at the same time, the small diameter is reduced through the switching chamber communication passage 34. The part upper surface 411 also receives the same pressure. However, since there is a difference in area between the small diameter portion upper surface 411 and the large diameter portion lower surface 422, the piston 40 is in a state of receiving a force in the direction from the bottom to the top. When the force exceeds the urging force of the first spring 51, the piston 40 moves upward. When the pressure applied to the piston 40 becomes sufficiently large, as shown in FIG. 2, the piston is moved upward as much as possible, that is, the volume of the first chamber 26 is minimized. In this state, the connection port of the first fuel supply passage 23 and the position of the communication port of the piston inner passage 43 on the small diameter side surface 412 coincide with each other, and the first fuel supply passage 23 and the piston inner passage 43 communicate with each other. Note that the pressure at which the piston 40 starts to move upward is referred to as a switching set pressure.

Next, the operation of the sub-chamber gas engine 10 configured as described above will be described with reference to FIG.
In the intake stroke of the sub-chamber gas engine 10, the intake valve disposed in the intake port 16 of the main chamber 14 is opened by the intake cam. Further, since the combustion chamber piston 13 of the main chamber 14 moves in a direction (downward) in which the main chamber 14 is expanded, the main chamber 14 has a negative pressure, and fresh air is sucked into the main chamber 14 from the intake port 6. Is done. At this time, gaseous fuel is supplied to the fresh air to be sucked by a stroke described later, and the fresh air is in a leaner fuel state than the stoichiometric air-fuel ratio.

  In the intake stroke, the pressure in the sub chamber 15 communicating with the main chamber 14 is also negative, and the pressure in the second chamber 27 communicating with the sub chamber 15 is also reduced. Therefore, the piston 40 in the switching chamber 30 is disposed at a position where the second chamber 27 is minimized by the urging force of the first spring 51. In this state, the first chamber 26 and the second chamber 27 are communicated with each other by the switching chamber communication passage 34 and the piston passage 43 (state shown in FIG. 3).

  As shown in FIG. 4, the ECU 52 sends an instruction to supply gas fuel to the injector 21 in the latter half of the intake stroke, and the injector 21 is opened. The gas fuel supplied from the injector 21 passes through the first chamber 26, the piston passage 43, the switching chamber communication passage 34, the second chamber 27, and the second fuel supply passage 24 due to the negative pressure in the main chamber 14. To be supplied. The ECU 52 controls the opening degree and time for opening the injector 21 so that the gas fuel supplied to the sub chamber 15 has a rich air-fuel ratio.

  Next, in the compression stroke in which the combustion chamber piston 13 of the main chamber 14 rises in the cylinder block 11, the intake valve and the exhaust valve are closed by the intake cam and the exhaust cam. Therefore, the pressure in the main chamber 14 and the sub chamber 15 is gradually increased. As the pressure in the sub chamber 15 is increased, the pressure in the second chamber 27 and the pressure in the first chamber 26 communicated by the piston passage 43 and the switching chamber communication passage 34 are also increased. The pressure applied to the lower surface 422 of the large-diameter portion forming the second chamber 27 is the resultant force (switching) of the pressure applied to the upper surface 411 of the small-diameter portion forming the first chamber 26 and the urging force applied to the upper surface 421 of the large-diameter portion by the first spring 51. When it becomes larger than the set pressure), the piston 40 moves upward. When the pressure in the sub chamber 15 exceeds a certain value, the piston 40 moves as far as possible to move, that is, when the volume of the first chamber 26 is minimized, the in-piston passage 43 is connected to the first fuel supply passage 23. Thus, the first chamber 26 and the first fuel supply passage 23 communicate with each other.

  The ECU 52 ignites the air-fuel mixture that fills the sub chamber 15 with the spark plug 19 in a state where the combustion chamber piston 13 in the late compression stroke stage or the early expansion stroke stage is near the top dead center. Along with this, the air-fuel mixture in the sub chamber 15 is combusted, and the air-fuel mixture (flame) during combustion is ejected from the ejection port 18 to the combustion chamber, and the air-fuel mixture in the main chamber 14 starts to combust. In the expansion stroke, the combustion chamber piston 13 is pushed down by the pressure generated by the combustion of the air-fuel mixture in the main chamber 14. In the compression stroke and the expansion stroke in which the pressure in the main chamber 14 and the sub chamber 15 increases, the sub chamber 15, the second chamber 27, and the first chamber 26 are separated by the piston 40. The combustion pressure does not flow back to the injector 21.

In the exhaust stroke, the exhaust valve disposed in the exhaust port 17 is opened, and the burned gas is discharged to the exhaust port 17. Along with this, the pressure in the main chamber 14 decreases, but the combustion chamber piston 13 may rise, and a certain amount of pressure is applied in the main chamber 14 and the sub chamber 15. Therefore, the piston 40 continues to be maintained at the upper portion, and the first chamber 26 and the first fuel supply passage 23 are connected. The urging force of the first spring 51 is set to such a strength that the piston 40 of the switching chamber 30 is maintained at the upper part in the exhaust stroke.
From the middle of the exhaust stroke, the ECU 52 sends an instruction to supply fuel to the injector 21, and the injector 21 is opened. The gas fuel supplied from the injector 21 is supplied to the intake port 16 through the first chamber 26, the piston passage 43, and the first fuel supply passage 23 due to the negative pressure of the intake port 16. The ECU 52 controls the opening degree and time for opening the injector 21 so that the gas fuel supplied to the main chamber 14 has a lean air-fuel ratio.

When the combustion chamber piston 13 reaches top dead center and starts to descend again, the exhaust valve is closed and the intake valve is opened. Since the pressure in the main chamber 14 decreases as the combustion chamber piston descends, the piston 40 is disposed at a position where the second chamber 27 is minimized by the biasing force of the first spring 51.
The sub chamber type gas engine 10 obtains an output by repeating the above steps.

In this embodiment, the following effects can be obtained.
(1) In the stroke in which the pressure of the combustion chamber becomes high, such as the compression stroke and the expansion stroke, the injector 21 that is the fuel supply unit and the sub chamber 15 can be separated by the switching chamber 30 and the piston 40 that constitute the switching means 22. . Therefore, it is not necessary to install a check valve for preventing the gas fuel from flowing back to the fuel storage part through the injector 21, and the number of parts can be reduced.
(2) Since the injector 21 that supplies fuel to the intake port and the injector 21 that supplies fuel to the sub chamber use the same components, the number of injectors can be reduced.
(3) Since the piston 40 of the switching means 22 is driven using the pressure of the sub chamber 15, it is not necessary to provide a separate part for driving the switching means 22, and a simple configuration can be achieved.
(4) By providing the first spring 51 for urging the piston 40 downward and adjusting the urging force, the combustion gas can be reliably supplied to the sub chamber 15 in the intake stroke.
(5) Since fuel is supplied from the injector 21 when the in-piston passage 43 is in communication only with either the first fuel supply passage 23 or the switching chamber communication passage 34, it is supplied to the main chamber 14 and the sub chamber 15. The amount of fuel to be controlled can be accurately controlled.
(Second Embodiment)

  Next, the sub chamber type gas engine which is 2nd Embodiment is demonstrated according to FIG. 5, FIG. In this embodiment, the detailed structure that connects the first chamber 26 and the second chamber 27 in the switching means 22 is different from that of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, the switching means 62 includes a switching chamber 70 to which gas fuel is supplied from the injector 21, and a piston 80 as a valve body that is slidably disposed in the switching chamber 70. A first piston passage 83 (valve body passage) that communicates with the smaller diameter upper surface 811 (one pressure receiving surface) of the piston 80 is provided on the side surface 812 (valve sliding surface) of the piston 80. . The large-diameter side surface 823 (valve sliding surface) is provided with a second piston internal passage 84 (valve internal passage) that communicates with the small-diameter upper surface 811 communication port of the first piston internal passage 83. The first switching chamber 71 and the small-diameter portion upper surface 811 (one pressure receiving surface) constitute the first chamber 26, and the second switching chamber 72, the third switching chamber 73, and the large-diameter portion lower surface 822 (the other pressure receiving surface). ) Constitutes the second chamber 27.

  In addition, as shown in FIG. 6, the piston 80 is inserted into the switching chamber 70, and the piston 80 is moved downward as much as possible, that is, in a state where the volume of the second chamber 27 is minimized. The second switching chamber side surface 723 that contacts the large diameter side surface 823 communication port of the inner passage 84, the second switching chamber side surface 723 positioned below the second switching chamber side surface 723, and a part of the third switching chamber side surface 732 include the second switching chamber side surface 723. A switching chamber communication path 74 that connects the switching chamber 72 and the third switching chamber 73 is provided. The switching chamber communication passage 74 in this embodiment is not an independent passage, but is formed as a notch that straddles the second switching chamber 72 and the third switching chamber 73. However, as in the first embodiment, It may be independent.

  As shown in FIG. 5, in the state where the piston 80 has moved upward as much as possible, that is, in the state where the volume of the first chamber 26 is minimized, the communication port of the first piston passage 83 on the side surface 812 of the small diameter portion is The first fuel supply passage 23 is formed on the side surface 712 of the first switching chamber. In this state, the communication port of the second piston passage 84 arranged on the large-diameter side surface 823 and the switching chamber communication passage 74 are not connected.

Next, the operation of the switching means 62 configured as in the second embodiment will be described.
As shown in FIG. 6, in the state where the pressure is not applied to the small diameter upper surface 811 and the large diameter lower surface 822 of the piston 80, the piston 80 is moved downward as much as possible by the urging force of the first spring 51, The state where the volume of the second chamber 27 is minimized is maintained. In this state, the position of the communication port of the switching chamber communication passage 74 disposed on the second switching chamber side surface 723 and the position of the communication port of the second piston internal passage 84 on the large-diameter side surface 823 coincide with each other. And the second chamber 27 communicate with each other. At this time, the communication port of the first piston passage 83 in the small-diameter side surface 812 is located below the connection port of the first fuel supply passage 23 arranged in the first switching chamber side surface 712. The one-piston passage 83 and the first fuel supply passage 23 are not connected.

  When pressure is applied to the second chamber 27 from a state where no pressure is applied to the small diameter upper surface 811 and the large diameter lower surface 822 of the piston 80, the large diameter lower surface 822 receives pressure, and at the same time, the switching chamber communication passage 74, The upper surface 811 of the small diameter part also receives the same pressure through the two-piston passage 84. However, since there is a difference in area between the small-diameter portion upper surface 811 and the large-diameter portion lower surface 822, the piston 80 is in a state of receiving pressure in a direction from the bottom to the top. When the force exceeds the urging force of the first spring 51, the piston 80 moves upward. When the pressure applied to the piston 80 becomes sufficiently large, as shown in FIG. 5, the piston 80 is moved upward as much as possible, that is, the volume of the first chamber 26 is minimized. In this state, the connection port of the first fuel supply passage 23 and the position of the communication port of the first piston passage 83 on the small diameter side surface 812 coincide with each other, and the first fuel supply passage 23 and the first piston passage 83 communicate with each other. Is done. At this time, the communication port of the second piston passage 84 in the large-diameter side surface 823 is located above the communication port of the switching chamber communication channel 74 disposed on the second switching chamber side surface 723. The two-piston passage 84 and the switching chamber communication passage 74 are not connected.

  The sub-chamber gas engine configured as described above can be operated with the same action as in the first embodiment.

According to the second embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
(6) Since only the passage directly connected to the side surface and the upper surface needs to be formed in the switching chamber 70 or the piston 80, the processing is easy.

The embodiment is not limited to the above, and may be embodied as follows, for example.
As shown in FIG. 7, the second spring 55 may be provided between the large-diameter portion lower surface 422 and the second switching chamber lower surface 322 or between the large-diameter portion lower surface 422 and the third switching chamber lower surface 331. Good. In this case, the biasing force of the first spring 51 and the second spring 53 is adjusted so that the pressure (switching set pressure) in the sub chamber 15 at which the piston 40 rises is the same as in the first embodiment. As a result, the piston 40 moves suddenly due to the pressure in the sub chamber 15, and when the piston 40 descends, vibration and sound that the large diameter portion lower surface 422 collides with the second switching chamber lower surface 322 are suppressed. be able to.
As shown in FIG. 7, the connection port of the first fuel supply passage 23 connected to the first switching chamber 31 or the switching chamber communication passage 34 in the first embodiment may be formed in a tapered shape. The location where the connection port is formed in a tapered shape is not limited to the above-described portion, and the communication port provided on each of the small diameter side surface 412 of the in-piston passage 43, the small diameter side surface 812 and the large diameter side surface 823 in the second embodiment, The connection port of the switching chamber communication path 74 may be sufficient. Thereby, the inflow of the gas between each connection port and the communication port becomes smooth, and it is possible to suppress the pistons 40 and 80 from moving suddenly.
The injector 21 is used for supplying gas fuel. However, the present invention is not limited to this, and supply means such as a mixer may be used.
The injector 21 and the first chamber are connected using the passage 25, but the present invention is not limited to this, and the injector 21 and the first chamber may be arranged directly in the first chamber.
The timing for supplying fuel from the injector 21 is calculated from the rotational speed sensor 53 and the accelerator opening sensor 54. However, the present invention is not limited to this, and a timing for opening and closing the injector based on the value of the negative pressure sensor is provided in the intake port. May be controlled.
○ The piston is moved in the switching chamber by receiving the pressure in the sub chamber 15 at the pressure receiving surfaces (411 and 422) of the piston 40, but this is not restrictive, and the piston is driven by driving means such as an actuator. May be. In that case, a pressure sensor is provided in the sub chamber, and the driving means is driven so as to have the same arrangement as in FIG. 4 according to the output value.
Although the first fuel supply passage 23 is connected to the intake port 16 as an intake pipe, the present invention is not limited to this, and the first fuel supply passage 23 may be connected to an intake pipe upstream of the intake port.
○ The first switching chamber is aligned in the piston circumferential direction between the connection ports of the first fuel supply passage 23 and the switching chamber communication passage 34 connected to the switching chamber 30 and the communication port of the passage in the piston in the piston 40. Although it carried out by preventing rotation of the piston 40 by the protrusion part 313 provided in 31 and the notch part 413 provided in the small diameter part 41 of the piston 40, you may use not only this but another method. For example, as shown in FIG. 7, an annular groove 44 is formed on the entire circumference of the position where the piston passage 43 communication port is formed on the side surface 412 of the small diameter portion of the piston 40, and the piston passage is formed in the annular groove 44. 43 may be connected. In that case, a plurality of in-piston passages 43 connected to the annular groove 44 may be provided. As a result, the gas fuel flowing from the piston inner passage 43 can communicate with the first fuel supply passage 23 or the switching chamber communication passage 34 through the annular groove 44, and the piston 40 rotates in the switching chamber 30. Even if it does, it becomes possible to supply gas fuel.
O Although rotation prevention with the switching chamber 30 and the piston 40 was performed by the protrusion part 313 provided in the 1st switching chamber 31, and the notch part 413 provided in the small diameter part 41 of the piston 40, it is not restricted to this. The method may be used. For example, the protruding portion may be formed in the second switching chamber 32 and the notched portion may be formed in the large diameter portion 42, or the notched portion may be formed on the switching chamber side and the protruding portion may be formed on the piston side. Further, the switching chamber and the piston may be formed in a non-rotating shape such as an ellipse.
Although the sub chamber is formed in the cylinder head 12, it is not limited to this and may be formed in the cylinder block 11. In that case, the cylinder block 11 and the combustion chamber piston 13 are set so that the injection hole can be formed in the cylinder block 11 even when the combustion chamber piston 13 is located at the top dead center.

DESCRIPTION OF SYMBOLS 10 ... Subchamber type gas engine, 14 ... Main chamber (main combustion chamber), 15 ... Subchamber, 16 ... Intake port (intake pipe), 20 ... Fuel supply device (fuel supply part), 22 ... Switching means, 23 ... 1st fuel supply passage, 24 ... 2nd fuel supply passage, 26 ... 1st chamber, 27 ... 2nd chamber, 30 ... Switching chamber, 40 ... Piston (valve body), 411 ... Small diameter part upper surface (one pressure receiving surface) 422 ... Lower surface of the large-diameter portion (the other pressure receiving surface), 43 ... Passage in the piston (passage in the valve body), 51 ... First spring (first valve body urging means), 60 ... Sub chamber type gas engine, 62 ... Switching means, 70 ... switching chamber, 80 ... piston (valve element), 811 ... small diameter upper surface (one pressure receiving surface), 822 ... large diameter lower surface (the other pressure receiving surface), 83 ... first piston passage (valve) Body passage), 84 ... second piston passage (valve passage)

Claims (5)

A sub-chamber gas engine having a sub-chamber connected to the main combustion chamber,
A fuel supply section for supplying fuel;
A first fuel supply passage connecting the fuel supply unit and the intake pipe;
A second fuel supply passage connecting the fuel supply unit and the sub chamber;
Switching means disposed in the fuel supply unit, for switching communication between the fuel supply unit and the first fuel supply passage or the second fuel supply passage;
For each combustion chamber,
The switching means is
A switching room,
A valve body slidably inserted into the switching chamber;
The sub-chamber type is configured to switch communication between the fuel supply section and the first fuel supply passage or the second fuel supply passage when the valve body slides in the switching chamber. Gas engine. The valve body is
The sub-chamber gas engine according to claim 1, wherein the sub-chamber gas engine slides in the switching chamber according to the pressure of the sub-chamber. The valve body is formed in a piston shape,
A first chamber formed by one pressure receiving surface of the valve body and the switching chamber, and connected to the fuel supply unit;
A second chamber formed by the other pressure receiving surface of the valve body and the switching chamber, to which the second fuel supply passage is connected;
A valve body passage communicating the one pressure-receiving surface of the valve body forming the first chamber and the valve body sliding surface;
The first fuel supply passage is formed at a position where the valve body passage and the first fuel supply passage communicate with each other in a state in which the volume of the first chamber is minimized. The sub-chamber gas engine according to claim 1 or 2, wherein the valve body passage and the second chamber communicate with each other in a state where the volume of the chamber is minimized.   The sub-chamber type according to any one of claims 1 to 3, wherein an area of the other pressure receiving surface of the second chamber is larger than that of the one pressure receiving surface of the first chamber. Gas engine.   5. The first valve body urging means for urging the valve body in a direction in which the volume of the second chamber decreases is provided. 5. Sub-chamber gas engine.

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