JP2008025357A - Fuel supply device for gas engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device for a gas engine, performing a control of opening of a main passage and a slow passage by a single drive means. <P>SOLUTION: The fuel supply device comprises: the main passage 30 supplying fuel to the gas engine and having an outlet 30b disposed upstream of a throttle valve 21 disposed to an intake passage; and the slow passage 31 supplying the fuel to the gas engine and having an outlet 31b downstream of the throttle valve 21 of the intake passage 14. A slide valve 34 has a first opening 36a controlling the opening of the main passage 30 and a second opening 36b controlling the opening of the slow passage 31. A slide valve drive motor 38 drives the slide valve 34 so that a communication state between the first opening 36a and the main passage 30 is changed and the second opening 36b communicates with the slow passage 31 in the maximum opening of the main passage 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel supply device for a gas engine.

  In a gas engine using city gas or liquefied petroleum gas (LPG) as a fuel, as shown in FIG. 3, a throttle part (venturi) 52 is provided in the intake passage 51 and a throttle valve 53 is provided downstream thereof. . The fuel gas is supplied from the main passage 54 where the outlet 54 a opens to the throttle 52 and the slow passage 55 where the outlet 55 a opens downstream of the throttle valve 53. In the operating condition of the gas engine, when the amount of intake air is small and the fuel is to be concentrated (rich), the amount of air is small and the negative pressure generated in the throttle 52 is small. Since a sufficient amount of fuel gas cannot be secured, the slow passage 55 is necessary.

  Further, in order to keep the air-fuel ratio of the air-fuel mixture supplied to the gas engine at an appropriate level, the main passage 54 is provided with a needle type flow control valve. The needle-type flow control valve controls the flow rate by moving the needle 56 in the left-right direction in FIG. A throttle member (not shown) is fitted into the slow passage 55 so that the passage diameter is set small. Since the outlet 55a of the slow passage 55 is provided downstream of the throttle valve 53, when the throttle valve 53 is throttled, that is, when the amount of air is small, the pressure difference becomes large and the force for sucking out the fuel gas from the slow passage 55 is increased. growing.

Conventionally, as a mixing ratio control device for an LPG engine (LPG engine), in addition to the main passage and the slow passage, a correction air passage that bypasses the throttle valve interposed in the intake passage is provided, and the main passage is cut off in the main passage. An apparatus in which a valve is provided and a slow passage shut-off valve is provided in the slow passage has been proposed (see, for example, Patent Document 1). The device of Patent Document 1 controls an air flow rate control means for controlling the air flow rate of the correction air passage while the main passage is closed by the main passage cutoff valve and the slow passage cutoff valve is kept open during idle operation. Thus, the mixture ratio is controlled to approach the stoichiometric air-fuel ratio. Further, at the time of normal operation, at least the main passage shut-off valve is kept open, and the fuel supply amount and the air flow rate are controlled.
Japanese Utility Model Publication No. 61-178048

  By the way, in the former apparatus provided with a needle-type flow rate control valve in the main passage 54, if the diameter of the slow passage 55 is increased, the sensitivity when the flow rate of the main passage 54 is controlled by the movement of the needle 56 becomes dull. It is necessary to limit the diameter of the passage 55 to be small. However, if the diameter of the slow passage 55 is reduced, it may not be possible to secure the amount of fuel required when the fuel is desired to be richer than the normal operating state with a small amount of air.

  On the other hand, in the mixing ratio control device of Patent Document 1, an air flow rate control that controls the air flow rate of a correction air passage that is provided with a main passage cutoff valve and a slow passage cutoff valve and bypasses a throttle valve interposed in the intake passage. Since the means is provided, it becomes easy to control the air-fuel ratio to be suitable for idle operation and normal operation. However, in the apparatus of Patent Document 1, air flow control means for controlling the air flow rate of the main passage cutoff valve, the slow passage cutoff valve, and the correction air passage must be provided independently, and the structure and control become complicated. It is difficult to reduce the size of the device.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a fuel supply device for a gas engine that can control the opening degree of a main passage and a slow passage with a single drive means. It is to provide.

  In order to achieve the above object, the invention according to claim 1 supplies fuel to the engine, and has a main passage provided at an upstream side of a throttle valve having an outlet interposed in the intake passage, and fuel to the engine. And a slow passage provided at the downstream side of the intake passage with respect to the throttle valve. The slide valve having a first opening for controlling the opening of the main passage and a second opening for controlling the opening of the slow passage, and the slide valve are communicated with the main passage of the first opening. Driving means for changing the state and driving the second opening so as to be in a state of communicating with the slow passage at least at a maximum opening of the main passage from a state where the communication with the slow passage is blocked; It has. Here, “at the maximum opening of the main passage” means a state where the area of the portion where the main passage and the first opening overlap (overlapping portion) is maximized.

  In this invention, the opening degree of the main passage and the opening degree of the slow passage are adjusted by changing the position of the slide valve driven by one driving means. Therefore, the opening degree of the main passage and the slow passage can be controlled by a single drive means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the slide valve is rotatably provided, and the driving means is a motor. In this invention, the opening degree of the main passage and the slow passage is adjusted by rotating the slide valve by the motor. Therefore, the configuration is simplified and the apparatus can be downsized as compared with the configuration in which the slide valve is driven mechanically in conjunction with the accelerator means.

  The invention according to claim 3 is the invention according to claim 2, wherein the slide valve has a fan-shaped portion provided with the first opening and the second opening, and a fan-shaped gear portion having a diameter smaller than the diameter of the fan-shaped portion. The fan-shaped gear portion meshes with a gear driven by the motor. According to the present invention, it is possible to reduce the size of the slide valve and the size of the device as compared with the case where the slide valve is simply circular.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the second opening of the slide valve is in the state where the main passage is at a maximum opening degree and the second opening is the slow opening. It is driven to communicate with the passage. According to the present invention, fuel that is insufficient when the main passage reaches the maximum opening can be supplied via the slow passage, and the slow passage does not adversely affect the opening of the main passage.

  According to the present invention, the opening degree of the main passage and the slow passage can be controlled by one drive means.

Hereinafter, an embodiment in which the present invention is applied to a gas engine as a drive source of a gas heat pump type air conditioner will be described with reference to FIGS. 1 and 2.
As shown in FIG. 2, the output shaft of the gas engine 11 is connected to the drive shaft of the compressor 13 of the heat pump 12. City gas is used as the fuel gas of the gas engine 11. A mixer 15 is provided in the middle of the intake passage 14 connected to the intake port of the gas engine 11, and the mixer 15 is connected to a city gas pipe (not shown) via a fuel supply unit 16 and a pipe line 17. An on / off valve 18 and a regulator (pressure adjusting valve) 19 are provided in the middle of the pipe line 17.

  A throttle valve 21 that is operated by a motor 20 is provided downstream of the mixer 15. An air cleaner 22 is provided upstream of the mixer 15 in the intake passage 14. The intake passage 14 is provided with a temperature sensor 23 for detecting the temperature in the intake passage 14 and an air flow meter 24 for detecting the intake air amount upstream of the mixer 15 and downstream of the air cleaner 22. An air-fuel ratio sensor 26 is provided in the exhaust passage 25 connected to the exhaust port of the gas engine 11.

  As shown in FIG. 1A, the housing 27 of the fuel supply unit 16 is configured to be divided into a main body 27a and a cover 27b. The cover 27b includes a seal member 28 (for example, a gasket) and a main body 27a. It is fastened and fixed by a bolt (not shown) in a state of being interposed between the two. The main body 27a is provided with an accommodation space 29a for accommodating a slide valve and the like which will be described later. The cover portion 27b is provided with a space 29b that communicates with the accommodation space 29a, and is fixed so that the end of the pipe line 17 communicates with the space 29b.

  The main body 27 a includes a main passage 30 that supplies fuel to the gas engine 11 and a slow passage 31. The main passage 30 is provided such that an inlet 30a opens into the accommodation space 29a and an outlet 30b opens upstream from the throttle valve 21 interposed in the intake passage 14. As shown in FIG. 1A, the mixer 15 includes a throttle part (venturi) 32. The throttle portion 32 includes an annular passage 33 that constitutes a part of the main passage 30 inside, and a plurality of holes that communicate the annular passage 33 and the intake passage 14 are provided. Each hole serves as an outlet 30 b of the main passage 30. . That is, the fuel gas passing through the main passage 30 is supplied to the intake passage 14 from the plurality of outlets 30b.

  The slow passage 31 is provided such that the inlet 31a opens into the accommodation space 29a and the outlet 31b opens downstream from the throttle valve 21 interposed in the intake passage 14. More specifically, the outlet 31b is the width of the intake passage 14 when the throttle valve 21 is in a large throttle state, that is, when the throttle valve 21 is disposed at a position where the distance between the throttle valve 21 and the wall surface of the intake passage 14 is narrow. It opens downstream from the narrow portion 14a. The slow passage 31 is formed with a cross-sectional area smaller than that of the main passage 30.

  In the accommodation space 29a, a flow control slide valve 34 is rotatably supported by a support shaft 35 so as to be slidable in the main body 27a. As shown in FIG. 1B, the slide valve 34 includes a sector portion 36 and a sector gear portion 37 having a diameter smaller than that of the sector portion 36. A slide valve drive motor 38, which is a motor as drive means, is fixed to the outside of the cover portion 27b. The drive shaft 38a of the slide valve drive motor 38 passes through the cover portion 27b and protrudes into the accommodation space 29a, and a gear 39 is fixed to the tip of the drive shaft 38a so as to be integrally rotatable. The sector gear portion 37 is in mesh with the gear 39. The slide valve 34 is rotated via a gear 39 by a slide valve drive motor 38. Note that the slide valve driving motor 38 is fixed between the surface of the cover portion 27b and a sealing member (not shown) so as to maintain the airtight state of the accommodation space 29a.

  The sector 36 is provided with a first opening 36 a that controls the opening of the main passage 30 and a second opening 36 b that controls the opening of the slow passage 31. The shape of the first opening 36a is such that the first opening 36a has a portion that overlaps a part of the inlet 30a of the main passage 30 and a portion that overlaps all of the inlet 30a, and the area of the overlapping portion with the inlet 30a is minimized. From the reference position of the slide valve 34, the area of the overlapping portion is gradually increased as the slide valve 34 rotates. Further, the length of the portion where the first opening 36a overlaps with all of the inlet 30a of the main passage 30 is such that the slide valve 34 is rotated while the inlet 31a of the slow passage 31 can communicate with the second opening 36b. The length is set so as to be able to face the entire inlet 30a. That is, the first opening 36a is always maintained in a state (opening degree 100%) that overlaps the entire area of the inlet 30a while the slide valve 34 is rotated in a state where the second opening 36b communicates with the slow passage 31. It has become so.

  The shape of the second opening 36b is such that the second opening 36b has a portion that overlaps a part of the inlet 31a of the slow passage 31 and a portion that overlaps the whole of the inlet 31a, and overlaps a part of the inlet 31a. It is formed so that the area of the overlapping portion gradually increases as the slide valve 34 rotates.

  The positional relationship between the inlet 30a of the main passage 30 and the inlet 31a of the slow passage 31 and the first opening 36a and the second opening 36b of the slide valve 34 is the second when the main passage 30 is at the maximum opening. An opening 36 b is formed so as to be able to communicate with the slow passage 31. That is, the slide valve 34 is driven so that the second opening 36 b communicates with the slow passage 31 in a state where the main passage 30 reaches the maximum opening.

  As shown in FIG. 2, the control device 40 that controls the operation of the gas engine 11 includes a microcomputer 41. The microcomputer 41 includes a memory (ROM and RAM) 42. The temperature sensor 23, the air flow meter 24, the air-fuel ratio sensor 26, the water temperature sensor 43 that detects the water temperature in the gas engine 11, and the rotation speed sensor 44 that detects the rotation speed of the gas engine 11 are the input side (input interface) of the control device 40. ) Are electrically connected to each other. The on / off valve 18, the regulator 19, the motor 20, and the slide valve drive motor 38 are electrically connected to the output side (output interface) of the control device 40, respectively.

  The control device 40 determines the operating state of the gas engine 11 based on detection signals output from the sensors, and the motor 20 and the slide valve driving motor 38 so that the target air-fuel ratio corresponding to the target operating state is obtained. To control the intake air amount and the fuel gas supply amount. The control device 40 controls the air-fuel ratio so that the gas engine 11 performs combustion in a leaner state than the stoichiometric state during normal operation.

Next, the operation of the apparatus configured as described above will be described.
During operation of the gas engine 11, the on / off valve 18 is held in an on state by a signal from the control device 40, city gas is supplied to the pipe line 17, adjusted to a predetermined pressure by the regulator 19, and then supplied with fuel. Sent to section 16. The control device 40 grasps the operating state of the gas engine 11 from detection signals from the water temperature sensor 43 and the rotation speed sensor 44. During normal operation, the control device 40 controls the air-fuel ratio so that the gas engine 11 performs a combustion operation in a state that is leaner than the stoichiometric state while satisfying the required rotational speed and load on the heat pump 12 side. Information on the required rotational speed and load on the heat pump 12 side is input to the control device 40 from an air conditioning control device (not shown) that controls the gas heat pump air conditioner in general.

  The control device 40 controls the motor 20 and the slide valve driving motor 38 to control the intake air amount (air flow rate) and the fuel gas supply amount so that the target air-fuel ratio corresponding to the required rotational speed and load is obtained. By driving the motor 20, the angle θ formed with the axial direction of the intake passage 14 of the throttle valve 21 is changed to adjust the intake amount, and the intake amount decreases as the angle θ increases. The intake air amount is confirmed based on a detection signal from the air flow meter 24.

  When the slide valve drive motor 38 is driven, the slide valve 34 is rotated via the gear 39. If the angle θ of the throttle valve 21 is the same, the amount of fuel gas supplied from the fuel supply unit 16 to the intake passage 14 increases as the amount of rotation of the slide valve 34 from the reference position increases.

  In the state where the slide valve 34 is disposed at the reference position, the main passage 30 communicates with the first opening 36a, and the area of the overlapping portion between the first opening 36a and the inlet 30a is kept to a minimum, and the slow passage 31 is held out of communication with the second opening 36b. As the slide valve 34 is rotated and the amount of rotation from its reference position increases, the area of the overlapping portion between the inlet 30a of the main passage 30 and the first opening 36a gradually increases. When the area of the overlapping portion between the inlet 30a and the first opening 36a reaches the maximum state (the state indicated by the solid line in FIG. 1B), the slide valve 34 is further rotated in the same direction. The slow passage 31 and the second opening 36b can communicate with each other. When the slide valve 34 is further rotated in the same direction from that state, the area of the overlapping portion between the inlet 31a of the slow passage 31 and the second opening 36b gradually increases as the amount of rotation increases. In the state shown by the solid line in FIG. 1B, the slide valve 34 is rotated clockwise in FIG. 1B, and the position indicated by the two-dot chain line, that is, the whole of the inlet 31a and the second opening 36b overlap. The opening degree of the slow passage 31 is maximized. On the other hand, while the slide valve 34 is rotated in a state where the slow passage 31 and the second opening 36b can communicate with each other, the area of the overlapping portion between the inlet 30a of the main passage 30 and the first opening 36a is maximized. Retained.

  There may be a case where a large amount of fuel is desired to be supplied with a small amount of intake air, such as when the gas engine 11 is started or when the load is low due to low rotation. In this state, since the intake air amount is small, the negative pressure generated in the throttle portion 32 where the outlet 30b of the main passage 30 exists is not sufficient, and the amount of fuel supplied from the main passage 30 can ensure the target amount. Can not. In this case, the fuel gas can be supplied also from the slow passage 31, that is, the slow passage 31 and the second opening 36b are brought into communication. When the amount of intake air is small, the throttle valve 21 is in a state where the angle θ is large, the flow velocity of the airflow flowing near the outlet 31b of the slow passage 31 is increased, and fuel is effectively supplied from the slow passage 31. The required amount of fuel can be secured.

According to this embodiment, the following effects can be obtained.
(1) The fuel supply unit 16 supplies fuel to the gas engine 11, and the main passage 30 provided at the upstream side of the throttle valve 21 with the outlet 30 b interposed in the intake passage 14, and the maximum of the main passage 30 Fuel can be supplied to the gas engine 11 at the time of opening, and an outlet 31b is provided with a slow passage 31 provided downstream of the throttle valve 21. The fuel supply unit 16 includes a slide valve 34 having a first opening 36 a that controls the opening degree of the main passage 30 and a second opening 36 b that controls the opening degree of the slow passage 31. Further, the slide valve 34 is changed from the state where the communication with the main passage 30 of the first opening 36 a is changed and the communication with the slow passage 31 is blocked from the second opening 36 b at the maximum opening of the main passage 30. A slide valve drive motor 38 that is driven to communicate with the passage 31 is provided. Accordingly, the opening degree of the main passage 30 and the opening degree of the slow passage 31 are adjusted by changing the position of the slide valve 34 driven by one slide valve driving motor 38. The opening degree can be controlled by a single driving means. As a result, the structure of the device is simplified and the size can be reduced as compared with the configuration in which the opening adjustments of the main passage 30 and the slow passage 31 are respectively performed by separate driving means.

  In addition, in the configuration in which flow control is performed using a needle valve, the coaxiality between the needle valve and the main passage greatly affects the flow rate adjustment accuracy associated with the amount of movement, and the needle valve is assembled in a cantilever state. This makes it difficult to improve the adjustment accuracy. However, in the configuration in which the flow rate is controlled by rotating the slide valve 34 and changing the area of the overlapping portion of the first opening 36a and the inlet 30a or the area of the overlapping portion of the second opening 36b and the inlet 31a, Such a malfunction can be suppressed.

  (2) The slide valve 34 is rotatably provided, and the opening degree of the main passage 30 and the slow passage 31 is adjusted by turning the slide valve 34 by the slide valve driving motor 38. Therefore, the structure is simpler and the apparatus can be made smaller than the structure in which the slide valve 34 is driven in mechanical linkage with the accelerator means.

  (3) The slide valve 34 includes a fan-shaped portion 36 provided with a first opening 36a and a second opening 36b, and a fan-shaped gear portion 37 having a diameter smaller than the diameter of the fan-shaped portion 36. The fan-shaped gear portion 37 is driven by a slide valve. Is engaged with a gear 39 driven by the motor 38 for use. Therefore, the slide valve 34 can be downsized and the fuel supply unit 16 can be downsized as compared with the case where the slide valve 34 is formed in a simple circular shape. Further, in the conventional configuration in which the opening degree of the main passage is adjusted by a needle valve, the needle valve is moved in the axial direction by a stepping motor, but the accuracy is performed in units of about 0.05 mm in one step. Therefore, if a stepping motor equivalent to that is used for the slide valve drive motor 38, the amount of rotation of the slide valve 34, that is, the opening degree of the main passage 30 and the slow passage 31 is adjusted even if the radius of the sector gear portion 37 is reduced. The accuracy can be increased. Further, if the radius of the sector gear portion 37 is increased, an inexpensive motor with low accuracy can be used as the slide valve driving motor 38.

  (4) The slide valve 34 is driven so that the second opening 36 b communicates with the slow passage 31 with the main passage 30 at the maximum opening. Therefore, fuel that is insufficient when the main passage 30 reaches the maximum opening can be supplied via the slow passage 31. When the opening of the main passage 30 is adjusted, that is, when the slide valve 34 is rotated within a range in which the area of the overlapping portion between the inlet 30a of the main passage 30 and the first opening 36a changes, the slow passage 31 is opened. Since the degree is kept at zero, unlike the conventional technique using a needle valve, the slow passage 31 does not adversely affect the opening degree of the main passage 30. In addition, in the conventional technique in which the opening of the main passage is adjusted with a needle valve, unnecessary fuel is supplied from the slow passage at low rotation and light load. In this configuration, such unnecessary fuel supply is performed. Can be cut.

  (5) In the prior art in which the opening of the main passage is adjusted with a needle valve, there is a trade-off relationship between the sensitivity of the flow control by the needle valve and the securing of the fuel supply amount from the slow passage. The range for ensuring the required amount of fuel with a small amount of air was narrow. However, the second opening 36 b is formed in a shape that can adjust the opening degree of the slow passage 31 as the slide valve 34 rotates. Therefore, compared to a configuration in which the opening degree of the slow passage 31 cannot be adjusted, when it is desired to supply a large amount of fuel with a small amount of intake air, the range in which the necessary fuel can be supplied is expanded according to the operating conditions.

  (6) A configuration is adopted in which the slide valve 34 and the gear 39 are accommodated in an accommodating space 29a that is kept airtight. Therefore, the slide valve 34 is provided in a state where the fan-shaped gear portion 37 is exposed to the outside of the housing 27, and it becomes easier to maintain airtightness as compared with a configuration in which the slide valve 34 meshes with the gear 39 outside the housing 27.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The slide valve 34 is not limited to a configuration that is driven so that the second opening 36b communicates with the slow passage 31 in a state where the main passage 30 has the maximum opening, but before the main passage 30 reaches the maximum opening. The second opening 36b may be formed in a shape in which the second opening 36b can communicate with the slow passage 31 and can communicate even after reaching the maximum opening.

  ○ The shape of the second opening 36b is such that the slide valve 34 rotates when the slide passage 34 is further rotated in the same direction from the state in which the slow passage 31 can communicate with the second opening 36b. Accordingly, the shape of the opening of the slow passage 31 is not limited to a continuously changing shape. For example, a plurality of holes having different sizes may be provided as the second opening 36b, and each hole may be intermittently communicated with the slow passage 31. Moreover, the number of holes may be one.

  In the state of the maximum opening degree of the main passage 30, not only the configuration in which the entire area of the inlet 30a overlaps the first opening 36a but also a shape in which a part of the inlet 30a protrudes from the first opening 36a.

  In the case where the slide valve 34 is driven by the slide valve driving motor 38 via the gear 39, the slide valve 34 is not limited to the shape including the sector part 36 and the sector gear part 37 but meshes with the gear 39. If the gear portion is provided and the first opening 36a and the second opening 36b are provided, the outer shape is free. For example, the slide valve 34 may be a disc, and a gear portion may be formed on the peripheral surface of the disc, or the sector gear portion 37 and a polygon may be continuous.

  When the slide valve 34 is configured to be rotatable, the slide valve 34 is not limited to a configuration driven via a gear. For example, the slide valve 34 may be connected to a linear actuator such as an air cylinder or a linear motor as a driving means via a link or a wire, and the slide valve 34 may be rotated by driving the linear actuator. When the gas engine 11 is used as a driving source for running the vehicle, the slide valve 34 is connected to an accelerator operating means such as an accelerator pedal or an accelerator lever via a link or a wire, and the operation of the accelerator operating means is performed. It is good also as a structure driven in conjunction with.

  The slide valve 34 is not limited to the configuration provided to be rotatable. For example, the first opening 36a and the second opening 36b provided in the slide valve 34 change the communication state of the first opening 36a with the main passage 30 by the linear movement of the slide valve 34, and the second opening 36b Further, at least when the main passage 30 is at the maximum opening degree, it may be movable to a state where it communicates with the slow passage 31 and a state where the communication is blocked. The drive means for linear movement is not limited to a linear actuator, and a configuration may be adopted in which a rack portion is provided on the slide valve 34 and a gear that meshes with the rack portion is driven by a motor.

  The fuel supply unit 16 is not limited to a configuration in which the inlet 30a of the main passage 30 and the inlet 31a of the slow passage 31 are in communication with the accommodation space 29a. For example, instead of the configuration in which the regulator 19 and the housing 27 are connected by a single pipe line 17, the main passage 30 and the slow passage 31 are configured to communicate directly with the regulator 19, respectively. In addition, a slide valve 34 is interposed. In this case, it becomes easy to ensure the sealing performance between the slide valve 34 and the main passage 30 and the slow passage 31.

The gas engine 11 may be applied not only to the drive source of the heat pump 12 but also to the drive source of the generator, or not only to the stationary type but also to an automobile engine.
The fuel gas of the gas engine is not limited to city gas, but may be liquefied petroleum gas (LPG), for example.

The number of outlets 30b provided in the throttle unit 32 is not limited to a plurality, and may be one.
○ The diaphragm 32 may be omitted.
The following technical idea (invention) can be understood from the embodiment.

  (1) In the invention according to any one of claims 1 to 4, the second opening is formed in a shape capable of continuously changing the opening degree of the slow passage as the slide valve moves. Has been.

(A) is a schematic cross section of the fuel supply device of one embodiment, (b) is a schematic diagram showing the relationship between the slide valve and the gear. The schematic diagram which shows the gas engine and heat pump which comprise a gas heat pump. The schematic cross section of the fuel supply apparatus in a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gas engine, 14 ... Intake passage, 21 ... Throttle valve, 30 ... Main passage, 30b, 31b ... Outlet, 31 ... Slow passage, 34 ... Slide valve, 36 ... Fan section, 36a ... First opening, 36b ... First 2 openings, 37... Sector gear, 38... Slide motor driving motor as drive means motor, 39.

Claims (4)

A main passage provided on the upstream side of a throttle valve having an outlet disposed in the intake passage, while supplying fuel to the engine;
A slow passage which is capable of supplying fuel to the engine and whose outlet is provided downstream of the throttle valve of the intake passage;
A slide valve having a first opening for controlling the opening of the main passage and a second opening for controlling the opening of the slow passage;
The slide valve is changed so that the communication state of the first opening with the main passage is changed, and the second opening is at least at the maximum opening of the main passage from the state where the communication with the slow passage is blocked. A fuel supply device for a gas engine, comprising: a drive unit that is driven so as to communicate with the slow passage.   The fuel supply device for a gas engine according to claim 1, wherein the slide valve is rotatably provided, and the driving means is a motor.   The slide valve includes a fan-shaped portion having the first opening and the second opening, and a fan-shaped gear portion having a diameter smaller than the diameter of the fan-shaped portion, and the fan-shaped gear portion meshes with a gear driven by the motor. The fuel supply device for a gas engine according to claim 2.   The gas engine according to any one of claims 1 to 3, wherein the slide valve is driven so that the second opening communicates with the slow passage in a state where the main passage reaches a maximum opening. Fuel supply device.

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