JPH05209557A - Fuel supply device for gaseous fuel engine - Google Patents

Abstract

PURPOSE:To improve combustion stability by enhancing the control accuracy of fuel supply quantity in a low intake air quantity region while preventing the lowering of air volumetric efficiency in an operating region demanded to enhance output through the increase of air intake quantity in an engine using gaseous fuel such as hydrogen gas. CONSTITUTION:The engine is provided with a high pressure fuel supply system for supplying hydrogen gas into a cylinder from a high pressure hydrogen port 8 at high pressure after the termination of air intake, and a low pressure fuel supply system for supplying gas fuel into a cylinder at relatively low pressure during an air intake stroke. These systems are provided with fuel supply quantity regulating means 25, 28, and the low pressure fuel supply system is operated in a low intake air quantity region, whereas only the high pressure fuel supply system is operated in a high intake air quantity region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas fuel engine fuel supply system using a gas fuel such as hydrogen.

[0002]

2. Description of the Related Art In recent years, a gas fuel engine using a combustible gas such as hydrogen gas as a fuel has been developed.
When using gaseous fuel, its volume ratio is significantly larger than that of gasoline.Therefore, if the structure is such that the gaseous fuel is mixed with air in the intake passage and supplied to the combustion chamber, the amount of air intake will be greatly reduced. , Output reduction occurs. Even if the gaseous fuel is supplied to the combustion chamber through a route different from the route using the air as a container, the volumetric efficiency of the air can be increased if the gaseous fuel having a large volume ratio is present in the combustion chamber during the air intake. It is not possible to increase the engine output.

As a measure against such a problem, for example, in the device disclosed in Japanese Patent Publication No. 58-36172, a passage for intake of air and a passage for supply of hydrogen gas are separately provided, and intake valves and While the hydrogen supply valve is provided and the intake valve is closed at the bottom dead center, the hydrogen supply valve is opened at the bottom dead center so that the two valve open periods do not overlap and while the hydrogen supply valve is open. The hydrogen is sent to the combustion chamber at a pressure higher than the cylinder internal pressure. Further, in the apparatus disclosed in Japanese Patent Publication No. 58-36172, an air intake valve for supplying air to the combustion chamber and a fuel intake valve for supplying pressurized gaseous fuel are provided independently, and the fuel intake valve is an air The valve is opened near the bottom dead center just before the end of the suction stroke.

[0004]

In each of the devices disclosed in the above publications, the gas fuel is pressurized and supplied to the combustion chamber after the air intake is almost completed, so that the volumetric efficiency of the air is improved. It is preferable to increase the output in the high intake air amount range. However, since the fuel is supplied until the time when the pressure in the cylinder becomes considerably high after entering the compression stroke, the gaseous fuel is supplied at a considerably high pressure so that the fuel can be sent against the pressure in the cylinder at this time. There is a need. The fuel supply amount is controlled by a flow rate adjusting valve in the fuel passage, but when the fuel is supplied under high pressure as described above, it is difficult to accurately control the fuel supply amount. In the low intake air amount region, there is a possibility that the error of the fuel supply amount becomes relatively large and the combustion stability is hindered.

In view of the above circumstances, the present invention prevents a decrease in volumetric efficiency of air in an operating region in which it is required to increase an air intake amount to increase an output, while in a low intake air amount region. An object of the present invention is to provide a fuel supply device for a gas fuel engine, which can improve the control accuracy of the fuel supply amount and improve the combustion stability.

[0006]

In order to achieve the above object, a first aspect of the present invention (claim 1) is provided with an intake port for supplying air into a cylinder and supplying gaseous fuel into the cylinder. In the gas fuel engine equipped with a means for controlling the gas pressure, the gas fuel supply port opens in the cylinder separately from the intake port, and the pressure in the cylinder at that time in the first half of the compression stroke after the end of air intake from the intake port High-pressure fuel supply system for supplying the gaseous fuel into the cylinder at a higher pressure, and low-pressure fuel supply system for supplying the gaseous fuel to the cylinder at a pressure lower than the fuel supply pressure by the high-pressure fuel supply system during the air intake stroke. And a fuel supply amount adjusting means for each fuel supply system, and at least the low pressure fuel supply system is operated in the low intake air amount region of the engine. It was, in the high intake air quantity region of the engine is provided with a control means for operating only the high-pressure fuel supply system.

According to a second invention (claim 2), in the first invention, the low-pressure fuel supply system has a low-pressure gas fuel supply port which opens directly into the cylinder and is opened / closed according to the operation of the engine. The low pressure gaseous fuel supply port has an open period set within the open period of the intake port.

According to a third invention (claim 3), in the second invention, a rotor supported by an eccentric shaft is arranged in a cylinder constituted by a rotor housing and side housings on both sides thereof. In the piston engine, one of the side housings is provided with the intake port and the gaseous fuel supply port of the high-pressure fuel supply system, and the other side housing is provided with the low-pressure gaseous fuel supply port.

A fourth aspect of the present invention (claim 4) is characterized in that, in any of the first to third aspects of the invention, only the low pressure fuel supply system is operated in the low intake air amount region of the engine, and the middle intake of the engine is operated. The control means is configured to operate the low pressure fuel supply system and the high pressure fuel supply system in the air amount region, and operate the high pressure fuel supply system in the high intake air amount region of the engine.

According to a fifth invention (claim 5), in the first or fourth invention, the control means operates the low pressure fuel supply system when the engine is started or stopped. Is.

[0011]

According to the structure of the present invention, in the low intake air amount region, the required amount of air is small, and even if the gaseous fuel is supplied during the intake stroke, there is no shortage of air. The gas fuel is supplied at a low pressure, which is advantageous in terms of control accuracy. On the other hand, in the high intake air amount region, the gas fuel is supplied at a relatively high pressure after the intake stroke, thereby improving the volumetric efficiency of air. A decline can be avoided.

[0012]

Embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an embodiment of a fuel supply device for a gas fuel engine according to the present invention, and the engine of this embodiment is a rotary piston engine. Also, in the example,
Hydrogen gas is illustrated as the gaseous fuel.

The overall structure of the rotary piston engine and the fuel supply system is shown in FIG. The rotary piston has a cylinder constituted by a rotor housing 1 having an engine peritrochoidal inner peripheral surface and side housings 2 and 3 located on both sides thereof, and a substantially triangular rotor 4 inside thereof. It is arranged. In a two-rotor rotary piston engine, a front side cylinder and a rear side cylinder are formed in front of and behind the intermediate housing (intermediate side housing) 3, and a rotor 4 is arranged inside each of them. (See FIG. 4). The rotor 4 is supported by an eccentric shaft 5, the top portion of which is in sliding contact with the inner peripheral surface of the rotor housing 1, and three working chambers 6 are defined in the cylinder. With the eccentric rotation of the rotor 4, the volume of each working chamber 6 changes, and the Otto cycle is performed. The eccentric shaft 5 is rotationally driven by the rotation of the rotor 4.

On one side housing of this rotary piston engine, for example, the intermediate housing 3, an intake port 7 for supplying air is provided at a position facing the working chamber 6 in the intake stroke. Further, in this intermediate housing 3, a high-pressure hydrogen port (gaseous fuel supply port) 8 for supplying the relatively high-pressure hydrogen gas sent by the high-pressure fuel supply system to the working chamber 6 is provided independently of the intake port 7. It is provided. Further, the side housing 2 facing the intermediate housing 3 is provided with a low-pressure hydrogen port (low-pressure gas fuel supply port) 9 for supplying a relatively low-pressure hydrogen gas sent by a low-pressure fuel supply system to the working chamber 6. ing.

Air is supplied to the intake port 7 through an intake passage 11, and the intake passage 11 is provided with a throttle valve 12 operated by a step motor 13, and an air cleaner and an intake air amount not shown. An air flow meter or the like for detection is provided. Further, an exhaust port 14 is formed in the rotor housing 1 facing the working chamber in the exhaust stroke, and an exhaust passage 15 is formed in the exhaust port 14.
Is connected to the exhaust passage 15, and an O ₂ sensor (not shown),
A catalyst and the like are provided.

The system for supplying hydrogen gas as a gaseous fuel comprises a fuel passage 21 for sending hydrogen gas from a metal hydride tank (hereinafter referred to as MH tank) 20. The MH tank 20 has a hydrogen storage alloy capable of storing and releasing hydrogen therein, and a passage for hydrogen filling, a cooling water passage, and a heating water passage (not shown) are arranged in the MH tank 20. The hydrogen storage alloy provided in the MH tank is heated by the cooling water supplied from the engine water jacket to release hydrogen into the fuel passage.

The fuel passage 21 is branched into a high pressure side fuel passage 22 forming a high pressure fuel supply system and a low pressure side fuel passage 23 forming a low pressure fuel supply system, in the middle of the passage. The downstream end of 22 is connected to the high-pressure hydrogen port 8, while the downstream end of the low-pressure side fuel passage 23 is connected to the low-pressure hydrogen port 9. The high-pressure side fuel passage 22 is provided with a high-pressure pressure regulator 24, a flow rate regulating valve (fuel supply amount regulating means) 25, a timing valve 26, and the like, and the hydrogen gas supplied from the MH tank 20 is supplied. After the pressure is adjusted by the pressure adjuster 24 and the flow rate is adjusted by the flow rate adjusting valve 25, the timing valve 2
It is adapted to be supplied to the high-pressure hydrogen port 8 via 6. In the low pressure side fuel passage 23, a low pressure pressure regulator 27 and a flow rate regulating valve (fuel supply amount regulating means) 28 are provided.
Etc., the hydrogen gas supplied from the MH tank 20 is regulated by the pressure regulator 27, and the flow rate is regulated by the flow rate regulating valve 28.
To be supplied to.

A pressure regulator 24 for the high pressure side fuel passage 22.
MH tank 2 so that hydrogen gas can be sent to the working chamber 6 against the pressure in the working chamber 6 even during the compression stroke.
Adjust the hydrogen gas supplied from 0 to a relatively high pressure,
For example, the pressure is adjusted to about 5 atmospheres. on the other hand,
The pressure regulator 27 in the low pressure side fuel passage 23 is provided in the working chamber 6
The pressure of the hydrogen gas is adjusted to be sufficiently lower than the pressure regulator 24 for high pressure, which is sufficient to supply the hydrogen gas to the working chamber 6 during the air intake stroke in which the internal pressure is low. .. Further, each of the flow rate adjusting valves 25, 28 can control the flow rate of hydrogen gas in the fuel passages 22, 23 steplessly by using a duty solenoid valve, a proportional solenoid valve, or the like. And
When the flow rate adjusting valve 25 or 28 is fully closed, the hydrogen gas supply from that system is stopped.

The selection of the high-pressure fuel supply system and the low-pressure fuel supply system, and the control of the hydrogen gas supply amount and the like are performed by a control device composed of a control unit (ECU) 30. The ECU 30 includes a detection signal from a rotation speed sensor 31 that detects an engine rotation speed, a detection signal from an accelerator opening sensor 32 that detects an accelerator opening (accelerator pedal depression amount), a high pressure side fuel passage 22 and a low pressure side. Signals and the like from the pressure sensors 33 and 34 that detect the respective pressures in the fuel passage 23 are input. Further, a control signal is output from the ECU 30 to each of the flow rate control valves 25 and 28. In the illustrated example, since the opening of the throttle valve is electrically controlled according to the accelerator opening or the like, a control signal is also output to the actuator 13 of the throttle valve 12.

The ECU 30 operates at least the low pressure fuel supply system in the low intake air amount region of the engine and operates the high pressure fuel supply system in the high intake air amount region of the engine by performing control according to the flow chart described later. It constitutes a control means.

2 to 4 show specific structures of the intake port 7, the hydrogen ports 8 and 9 and the timing valve 26 in the hydrogen gas supply system.

The high-pressure hydrogen port 8 opens from the intermediate housing 3 to the working chamber 6 at a position where it does not interfere with the intake port 7 with a relatively large opening area for reducing the flow resistance. In this high-pressure hydrogen port 8,
The internal passages of the passage forming member 35 inserted into the intermediate housing 3 communicate with each other. The passage forming member 35 is formed in a cylindrical shape, and has therein two passages 36a and 36b divided into a front cylinder and a rear cylinder, and the downstream ends of the passages 36a and 36b are the front side. , The rear high-pressure hydrogen port 8 communicates with each other, and the upstream end communicates with the passages 37 a, 37 b following the timing valve 26. The passage forming member 35 may be a rotatable rotary valve, and an actuator may be connected to the rotary valve so that the flow rate of hydrogen can be controlled.

In the figure, two timing valves 26 are provided in parallel for both the front and rear cylinders. Each timing valve 26 has a poppet valve 38, and a timing valve drive camshaft 39. It is opened and closed by the provided cams 39a and 39b. The cam shaft 39 is rotatably supported by the housing, and a pulley 40 provided at one end of the cam shaft 39 is linked to the eccentric shaft 5 via a timing belt 41 (FIG. 1).
Therefore, the eccentric shaft 5 and the eccentric shaft 5 rotate synchronously.

The low-pressure hydrogen port 9 opens from the side housing 2 into the working chamber 6 at a position facing the intake port 7, and the low-pressure hydrogen port 9 has a downstream end of the low-pressure fuel passage 23. It is directly connected.

FIG. 5 shows a specific example of opening / closing timings of the intake port 7, the high-pressure hydrogen port 8, the timing valve 26, and the low-pressure hydrogen port 9. As shown in this drawing, the intake port 7 is arranged and arranged so that the intake port 7 is opened (indicated by reference numeral IP) during the period from the vicinity of the top dead center to the predetermined above after the bottom dead center by the rotation of the rotor 4. The shape is set.

The high-pressure hydrogen port 8 is also opened and closed by the rotation of the rotor 4, but is opened slightly later than the opening timing of the intake port 7 and then in the middle of the compression stroke which is considerably later than the closing timing of the intake port 7. The arrangement and shape are set so as to be closed (indicated by reference numeral HHP).
Further, the timing valve 26 is opened during a part of the opening period of the high-pressure hydrogen port 8, and the timing is set so that the closing of the intake port 7 corresponds to the opening timing of the timing valve 26. (Denoted by the symbol TV). In the high-pressure fuel supply system, the period in which the timing valve 26 is open is the hydrogen supply period. Further, the arrangement and shape of the low-pressure hydrogen port 9 are set so that the low-pressure hydrogen port 9 is opened (indicated by reference numeral LHP) only for a certain period during the suction stroke. In the low pressure fuel supply system, the valve opening period of the port 9 itself is the fuel supply period.

FIG. 6 shows the setting of the region determined in the control described later. In this figure, the zone A is the region where the low pressure fuel supply system is operated, and the intake air amount is lower than the determination line. It is on the side. Further, the B zone is a region where only the high pressure fuel supply system is operated, and is on the higher intake air amount side than the determination line.

FIG. 7 shows an example of hydrogen gas supply control performed by the ECU 30. In this flowchart, when the engine is started, first, in step S1, the engine speed and accelerator opening are read as input information, and in step S2, based on the input information, the operating state at that time is in the zone A in FIG. It is determined whether or not. When it is in the A zone, in step S3,
The low pressure fuel supply system is operated by opening the flow rate adjusting valve 28 of the low pressure side fuel passage 23, while the operation of the high pressure fuel supply system is stopped by closing the flow rate adjusting valve 25 of the high pressure side fuel passage 22. It In this case, the fuel supply amount is controlled by controlling the opening degree of the low-pressure side flow rate adjusting valve 28 according to the intake air amount.

On the other hand, not in zone A (in zone B)
In this case, in step S4, contrary to step S3, the operation of the low pressure fuel supply system is stopped by closing the flow rate adjusting valve 28 on the low pressure side, while the flow rate adjusting valve 25 on the high pressure side is opened. Thus, the high pressure fuel supply system is activated. In this case, the opening degree of the high-pressure side flow rate adjusting valve 25 is controlled according to the intake air amount and the like.

According to the apparatus of this embodiment as described above, in the low intake air amount region, the low pressure fuel supply system is operated, and the hydrogen gas adjusted to a relatively low pressure is sent from the low pressure hydrogen port 9 into the working chamber 6. Be done. In this case, since hydrogen gas is supplied in the air intake stroke, it is difficult to increase the intake amount of air, but since it is the region where the intake air amount and the fuel supply amount are originally reduced, the required amount is covered. It becomes possible easily. By supplying the hydrogen gas during the suction stroke in this way, the hydrogen gas can be supplied at a relatively low pressure, and by controlling the flow rate adjusting valve 28 in the low pressure supply state, the fuel supply amount can be controlled. The accuracy can be increased.

On the other hand, in the high intake air amount region, if the hydrogen gas is supplied during the intake stroke, the intake of air is hindered and the required amount cannot be covered, but at this time, the high pressure fuel supply system is operated and the timing valve 26 is turned on. Since the hydrogen gas is supplied through the suction stroke after completion of the suction stroke, the volumetric efficiency of air is increased. It is also effective in preventing backfire.

As a control when in the low intake air amount range, the high pressure fuel supply system may be operated in addition to the low pressure fuel supply system. In this case, the share ratio of both fuel supply systems may be set, the fuel supply amount of each system may be calculated accordingly, and the flow rate adjusting valves 25 and 28 may be controlled accordingly. Even in this case, compared to the case where hydrogen gas is introduced only from the high-pressure fuel supply system, it is advantageous to improve the accuracy of fuel control.

8 and 9 show another example of control. In this example, as the region setting, the A1 zone (low intake air amount region) below the first determination line in FIG. 8 and the A2 zone (medium intake air amount region) between the first and second determination lines are set. ) And the B zone (high intake air amount region) above the second determination line.

In the flowchart of FIG. 9, following the reading of the input information (step S11), it is determined which zone A1, A2, B is (steps S12, S1).
3). If it is in the A1 zone, step S14
Then, the low-pressure fuel supply system is operated, the operation of the high-pressure fuel supply system is stopped, and if it is in the A2 zone, step S15.
Thus, both the low pressure fuel supply system and the high pressure fuel supply system are operated. If it is the B zone, step S16.
Thus, the high pressure fuel supply system is activated and the low pressure fuel supply system is deactivated.

According to this example, in the medium intake air amount region,
While the required intake air amount in this region is ensured, the accuracy of control of the fuel supply amount is improved compared to the case where only the high pressure fuel supply system is operated.

10 and 11 show another embodiment of the engine to which the present invention is applied. The engine of this embodiment is a reciprocating engine and has a piston 51 in its cylinder.
In the upper combustion chamber 52, two intake ports 53, 54,
One exhaust port 55 and hydrogen port 56 open,
Intake valve 5 in intake ports 53, 54 and exhaust port 55
7 and an exhaust valve (not shown), and a hydrogen port 56 is provided with a timing valve 58. The timing valve 58 is formed of a poppet valve like the intake valve 57 and the exhaust valve, and a valve timing variable mechanism 59 is incorporated in the valve operating mechanism for this valve. The valve timing variable mechanism 59 switches the valve 58 between the timing of opening in the compression stroke and the timing of opening in the suction stroke. Further, a high pressure side fuel passage 62 and a low pressure side fuel passage 63 branched from a fuel passage 61 connected to the MH tank 60.
And the pressure regulators 64 and 65 and the flow regulating valve 6 respectively.
6, 67 are provided, and both passages 62, 63 are provided.
Are selectively connected to the hydrogen port 56 via the switching valve 68. And on the low intake air side,
The valve opening timing of the valve 58 is advanced and the low pressure side fuel passage 63 is connected to the hydrogen port 56. On the high intake air amount side, the valve opening timing of the valve 58 is delayed and the high pressure side fuel passage 62 is connected to the hydrogen port 56. It is designed to be connected to 56.

The apparatus of the present invention can be variously modified in addition to the above-mentioned embodiments, and modifications will be described below.

When the engine is started, it is desirable to operate only the low pressure fuel supply system. In other words, when starting,
There is no shortage of air because the intake air volume is small,
In addition, since the operating state is unstable, it is desirable to accurately control the fuel by operating the low pressure fuel supply system.

Further, the low pressure fuel supply system does not necessarily need to supply hydrogen directly into the cylinder, but may supply hydrogen to the intake passage.

Further, the fuel used in the gas fuel engine of the present invention is not limited to hydrogen gas, and city gas in which hydrogen and methane are mixed is also effectively applied.

[0041]

According to the first aspect of the invention, in the first half of the compression stroke after the end of the air intake from the intake port, the gas fuel is supplied from the gas fuel supply port into the cylinder at a pressure higher than the pressure in the cylinder at that time. A high-pressure fuel supply system for supplying and a low-pressure fuel supply system for supplying gaseous fuel to the cylinder at a pressure lower than the fuel supply pressure by the high-pressure fuel supply system during the air intake stroke are provided, and the fuel supply amount to these systems Since the adjusting means is provided and at least the low pressure fuel supply system is operated in the low intake air amount region of the engine and the high pressure fuel supply system is operated in the high intake air amount region of the engine, in the low intake air amount region. The low-pressure fuel supply improves the accuracy of fuel control, and the volumetric efficiency of air can be improved in the high intake air amount region. Therefore, it is possible to improve the combustion stability by improving the fuel control accuracy in the low intake air amount region and to improve the output in the high intake air amount region.

In this structure, as described in claim 2, the low-pressure fuel supply system has a low-pressure gas fuel supply port that opens directly into the cylinder and is opened and closed according to the operation of the engine. If the open period of the fuel supply port is set within the open period of the intake port, in addition to the above effects, even if gaseous fuel is supplied during the intake stroke in the low intake air amount region, the air is relatively smoothly supplied. It can be introduced into the combustion chamber.

Further, as described in claim 3, in the rotary piston engine, one of the side housings is provided with the intake port and the gaseous fuel supply port of the high pressure fuel supply system, and the other side housing is provided with the above-mentioned intake port. Providing low pressure gaseous fuel supply ports allows each port to be reasonably positioned without interference.

Further, as described in claim 4, only the low pressure fuel supply system is operated in the low intake air amount region of the engine, and the low pressure fuel supply system and the high pressure fuel supply system are operated in the medium intake air amount region of the engine. Is operated and the high pressure fuel supply system is operated in the high intake air amount region of the engine, it is possible to perform fuel control in each region and control that meets air intake requirements.

Further, if the low-pressure fuel supply system is operated at the time of starting the engine, the fuel control accuracy at the time of starting can be improved to improve the startability.

[Brief description of drawings]

FIG. 1 is an overall structural explanatory view of a gas fuel engine according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a main part.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a cross-sectional view taken along the line BB of FIG.

FIG. 5 is a diagram showing an example of opening and closing timings of an intake port, a hydrogen port and a timing valve.

FIG. 6 is an explanatory diagram showing an example of control area setting.

7 is a flowchart showing an example of control of fuel supply based on the area setting of FIG.

FIG. 8 is an explanatory diagram showing another example of control area setting.

9 is a flowchart showing an example of control of fuel supply based on the area setting of FIG.

FIG. 10 is a cross-sectional view showing another embodiment of the device of the present invention.

[Explanation of symbols]

 1 Rotor Housing 2 Side Housing 3 Intermediate Housing 4 Rotor 6 Working Chamber 7 Intake Port 8 High Pressure Hydrogen Port 9 Low Pressure Hydrogen Port 21 Fuel Passage 22 High Pressure Side Fuel Passage 23 Low Pressure Side Fuel Passage 25, 28 Flow Control Valve 26 Timing Valve 30 ECU

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Eiji Takano 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (5)

[Claims] 1. A gas fuel engine comprising an intake port for supplying air into a cylinder and means for supplying a gas fuel into the cylinder, wherein the gas fuel supply is opened in the cylinder separately from the intake port. A high pressure fuel supply system having a port for supplying gaseous fuel into the cylinder at a pressure higher than the pressure in the cylinder at the first half of the compression stroke after the end of air intake from the intake port, and the above during the air intake stroke. A low-pressure fuel supply system for supplying gaseous fuel to the cylinder at a pressure lower than the fuel supply pressure by the high-pressure fuel supply system is provided, and fuel supply amount adjusting means is provided for each of the fuel supply systems, and a low intake air amount of the engine. In the area, at least activate the low pressure fuel supply system,
A fuel supply device for a gas fuel engine, comprising control means for operating only a high pressure fuel supply system in a high intake air amount region of the engine. 2. The low-pressure fuel supply system has a low-pressure gas fuel supply port that opens directly into the cylinder and is opened / closed according to the operation of the engine, and the opening period of the low-pressure gas fuel supply port corresponds to the intake port. The fuel supply device for a gas fuel engine according to claim 1, wherein the fuel supply device is set within an open period. 3. In a rotary piston engine in which a rotor supported by an eccentric shaft is arranged in a cylinder composed of a rotor housing and side housings on both sides thereof, the intake port and the high-pressure fuel are provided in one of the side housings. 3. The fuel supply device for a gas fuel engine according to claim 2, wherein the gas fuel supply port of the supply system is provided, and the low pressure gas fuel supply port is provided on the other side housing. 4. A high intake of the engine is operated by operating only the low pressure fuel supply system in the low intake air amount region of the engine, and operating the low pressure fuel supply system and the high pressure fuel supply system in the medium intake air amount region of the engine. 4. The fuel supply device for a gas fuel engine according to claim 1, wherein the control means is configured to operate the high pressure fuel supply system in the air amount region. 5. The fuel supply device for a gas fuel engine according to claim 1, wherein the control means operates the low pressure fuel supply system when the engine is started and stopped.