JPH0727019A - Fuel feeder for gas fuel engine - Google Patents

Abstract

PURPOSE:To prevent the accidental fire by lean condition at the time of supplying fuel, changing a fuel direct supply means over to a fuel premixing and supply means, by setting the pressure of the gas fuel pressure adjuster of a fuel premixing and supply means lower than the pressure of the gas fuel pressure adjuster of the fuel direct supply means. CONSTITUTION:This feeder is provided with a fuel premixing and supply means 14 and 6, which suck gas fuel into an intake port and mix it with air in advance and supply it to a combustion chamber, and fuel direct supply means 12 and 7, which directly supply gas fuel into the combustion chamber. Both supply means 12, 14, 7, and 6 are changed over, being overlapped from the fuel direct supply means 12 and 7 to the fuel premixing and supply means 14 and 6 in specified load operation area. Moreover, the fuel premixing and supply means 14 and 6 and the fuel direct supply means 12 and 7 are provided with gas fuel pressure adjusters 17 and 16, each independently. And, the pressure of the gas fuel pressure adjuster 17 provided for the fuel premixing and supply means 14 and 6 is set lower than the pressure of the gas fuel pressure adjuster 16 provided for the fuel direct supply means 12 and 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for a gas fuel engine, and more particularly to a fuel supply device for a gas fuel engine which uses a combustible gas such as hydrogen, methane or ethane as a fuel.

[0002]

2. Description of the Related Art In recent years, various gas fuel engines using combustible gases such as hydrogen, methane and ethane as fuel have been proposed. In particular, hydrogen is expected as a pollution-free engine because it does not generate carbon dioxide gas by combustion and does not emit toxic unburned components.
By the way, as a fuel supply system for a gas fuel engine as described above, for example, as disclosed in Japanese Patent Application Laid-Open No. 2-86923, the gas fuel is premixed with air by a carburetor and then introduced into an intake port of the engine. A premixing system for supplying and direct injection of gaseous fuel into a cylinder in a compression process from a gaseous fuel supply port provided separately from an intake port, as disclosed in Japanese Patent Publication No. 58-36172. It is known that there is an injection method. However, in the former premixing method, the volume ratio of gaseous fuel to air at a combustible air-fuel ratio is so large that it is not comparable to atomized fuel such as gasoline (approximately 2: 1 to 1: 1).
3: 1), it becomes difficult for air to enter, so the amount of intake air becomes insufficient and the filling efficiency decreases. As a result, there is a problem in that the output is reduced particularly in the high load operation range of the engine.

On the other hand, the latter direct injection system has an advantage that a large amount of gaseous fuel can be supplied into the combustion chamber in a short time to obtain high output, but on the other hand, it is light in an engine such as an idle state. In the load operating range, the engine speed is low and the squish flow is weak, so mixing of the mixture of intake air and gaseous fuel in the combustion chamber is not good, there is a problem of abnormal combustion, and fuel consumption deteriorates. There was a problem.

[0004]

SUMMARY OF THE INVENTION In order to solve such conventional problems, the applicant of the present application filed Japanese Patent Application No. 4-12.
Filed No. 479. That is, in this prior application, the fuel premix supply means for supplying the gas fuel to the intake port to mix the gas fuel with the air in advance and supplying it to the combustion chamber, and the fuel premix supply means are provided separately in the combustion chamber. A direct fuel supply means for directly supplying the gaseous fuel is provided, and the gaseous fuel is supplied to the engine only by the fuel premixing supply means in the low load operation range, and the gaseous fuel is supplied at least by the direct fuel supply means in the high load operation range. It is described to be supplied to the engine. In the one described in this prior application, in the light load operation range, a small amount of gaseous fuel is supplied to the engine through the fuel premixing supply means, so this small amount of gaseous fuel is mixed with air in the intake passage, The rotation speed is low,
In addition, it is possible to improve mixing of the air-fuel mixture in a light load operation range where the squish flow is weak, which improves thermal efficiency and improves fuel efficiency. On the other hand, in the high load operating range, the gaseous fuel is supplied to the engine through the direct fuel supply means, so that the output in the high load operating range can be improved.

Thus, the one described in the prior application has the above-mentioned effects, but the following problems occur when shifting from the high load operating range to the light load operating range. That is, when shifting from the high load operating range to the light load operating range,
It is necessary to switch the fuel supply from the direct fuel supply means to the fuel supply from the fuel premix supply means. At this time, the fuel supply from the fuel premixing supply means may be delayed, resulting in a temporary lean state and a misfire. In order to prevent the misfire due to such a lean state, by overlapping the switching of the fuel supply by the direct fuel supply means and the fuel premixing supply means, it is possible to prevent the lean state and prevent the misfire. It is possible to However, in reality, during this overlap, most of the gaseous fuel enters the intake passage through the fuel premixing supply means and is not supplied into the combustion chamber through the direct fuel supply means, and therefore, It was discovered that there still existed the problem of a misfire due to lean conditions. Therefore, the present invention has been made in order to solve the problems of the above-mentioned prior application.
The fuel direct supply means for directly supplying the gaseous fuel into the combustion chamber is switched to the fuel premixing supply means for preliminarily mixing the gaseous fuel with the air at the intake port and supplying it to the combustion chamber to supply the gaseous fuel to the engine in a lean state. It is an object of the present invention to provide a fuel supply device for a gas fuel engine, which is designed to prevent a misfire due to

[0006]

In order to achieve the above object, the first invention of the present application is a fuel premixing system in which gaseous fuel is sucked into an intake port, the gaseous fuel is mixed with air in advance, and the mixed fuel is supplied to a combustion chamber. In a fuel supply device for a gas fuel engine equipped with a supply means, a fuel direct supply means for directly supplying a gaseous fuel to a combustion chamber, and a fuel premix supply from the gaseous fuel supply by the fuel direct supply means in a predetermined load operation range. Switching control means for switching the supply of the gaseous fuel to the supply of these means by overlapping them, and a gas fuel pressure regulator independently provided in the fuel premixing supply means and the fuel direct supply means. And the pressure of the gaseous fuel pressure regulator provided in the fuel premixing supply means is set lower than the pressure of the gaseous fuel pressure regulator provided in the fuel direct supply means. It is characterized in. In the first aspect of the present invention having such a configuration, since the gas fuel pressure regulator is provided independently of the fuel premix supply means and the fuel direct supply means, the fuel direct supply means is provided by the switching control means. When the supply of the gaseous fuel by the fuel premixing supply means is switched to the fuel supply of the gas by the fuel premixing supply means by overlapping them, even if the fuel supply delay occurs in the fuel premixing supply means, the direct fuel supply means burns the fuel. Since gaseous fuel is supplied to the room, it is possible to prevent a misfire due to a lean state. Further, since the pressure of the gas fuel pressure regulator provided in the fuel premix supply means is set lower than the pressure of the gas fuel pressure regulator provided in the fuel direct supply means, in the fuel premix supply means, Because of the low pressure, the gaseous fuel can be controlled and supplied with high precision. On the other hand, in the direct fuel supply means, because of the high pressure, the required gaseous fuel can be secured with high accuracy.

A second aspect of the present invention is a fuel supply device for a gas fuel engine, which is equipped with a fuel premixing supply means for sucking a gaseous fuel into an intake port, mixing the gaseous fuel with air in advance and supplying the mixture to a combustion chamber. A fuel direct supply means for directly supplying a gaseous fuel to the combustion chamber, a timing setting means for setting fuel supply timings of the fuel premixing supply means and the fuel direct supply means, and a downstream side of the timing setting means. Switching control means for switching from the gas fuel supply by the fuel direct supply means to the gas fuel supply by the fuel premixing supply means in a predetermined load operation range by overlapping these both supply means. I am trying. In the second aspect of the present invention thus configured, both of these supply means are overrun from the supply of the gaseous fuel by the fuel premix supply means to the supply of the gaseous fuel by the direct fuel supply means in a predetermined load operation range. Switching control means for switching by wrapping is provided downstream of the timing setting means for setting the fuel supply timing. Therefore, the ease with which fuel enters the combustion chamber by both of these supply means becomes substantially the same, and even if a fuel supply delay occurs in the fuel premixing supply means, gaseous fuel is supplied from the direct fuel supply means into the combustion chamber. Therefore, it is possible to prevent a misfire due to a lean state.

Further, in the second aspect of the present invention, it is preferable that the fuel premixing supply means has a throttle means downstream of the switching control means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an overall configuration diagram showing a rotary piston engine using hydrogen gas as a fuel, to which the present invention is applied, and showing a rotary piston engine equipped with two rotors in left and right development.
In FIG. 1, the rotary piston engine is provided with a triangular rotor 2 in a rotor housing 1 having a peritrochoid curve as an inner peripheral surface. The three ridge lines of the rotor 2 are in contact with the inner peripheral surface of the rotor housing 1 via apex seals, and are mounted on the inner peripheral surface of the rotor housing 1, the outer peripheral surface of the rotor 2, and both side surfaces of the rotor housing 1. The side housing (not shown) and the intermediate housing 3 define three working chambers 4, and the working chambers 4 perform an Otto cycle operation as the rotor 2 eccentrically rotates. Then, the eccentric shaft 5 is rotationally driven with the eccentric rotation of the rotor 2. It should be noted that the intermediate housing 3 is a wall member interposed between the right side (front side) cylinder F and the left side (rear side) cylinder R in FIG. , R rotors 2 come into contact with and slide through the side seals.
The rotors 2 of both cylinders F and R operate with a phase difference of 180 °.

An intake port 6 is opened at a predetermined position of the side housing and the intermediate housing 3 facing the working chamber 4 in the intake stroke of each cylinder F, R.
Further, with respect to the rotation of the rotor 2, the hydrogen injection port 7 is opened on the inner peripheral surface of the rotor housing on the leading side of the intake port 6 (see FIG. 2). The hydrogen supply source 10 is, for example, a metal halide tank equipped with a hydrogen storage alloy capable of storing and releasing hydrogen. Between the hydrogen supply source 10 and each of the hydrogen injection ports 7, various types described below are provided. Equipment is installed. First, a hydrogen supply line 11 is connected to the hydrogen supply source 10. The hydrogen supply line 11 supplies hydrogen to the hydrogen injection port 7 and a first hydrogen supply line 12 that supplies hydrogen to the intake port 6. It is branched to the second hydrogen supply line 14 for supplying. This first
The hydrogen supply line 12 is provided with a first pressure regulator 16 for reducing the hydrogen gas to a constant pressure, and the second hydrogen supply line 14 is similarly provided with a second pressure regulator 17. There is. Here, the hydrogen gas pressure of the second pressure regulator 17 is set lower than the hydrogen gas pressure of the first pressure regulator 16 by a predetermined value. A hydrogen flow rate control valve 18 and a normally closed solenoid valve 20 are provided in the hydrogen supply line 12 downstream of the first pressure regulator 16. The hydrogen flow rate control valve 18 has two functions that are interlocked with an accelerator pedal (not shown) that is depressed by the driver and that is controlled so as to obtain a predetermined air-fuel ratio according to the operating state of the engine. . Further, at the downstream end of the hydrogen supply line 12, the hydrogen supply lines 12a, 1 are branched into two.
2b is connected, and the hydrogen gas supplied to the hydrogen supply lines 12a and 12b is directly injected from the hydrogen injection port 7 into the working chamber at the initial stage of the compression process by the hydrogen injection valve 22 attached to the rotor housing 1. It is like this.

As shown in FIG. 2, this hydrogen injection valve 22
In the casing 24 of the hydrogen supply lines 12a, 1
2b and the hydrogen injection port 7 are provided in communication with each other, and a poppet valve 28 is arranged at an opening portion of the valve passage 26. The poppet valve 28 is a stem 2 slidably inserted in a guide 30 fixed to the casing 24.
8a, and the valve face 28b at the tip is pressed and biased toward the seat 34 by the spring 32. When the valve face 28b of the poppet valve 28 comes into close contact with the seat 34 by the urging force of the spring 32, the valve passage 26 is hermetically shut off, and the poppet valve 28 slides against the urging force of the spring 32 so that the valve passage is closed. 26 is configured to open. The camshaft 3 is provided diagonally above the stem 28a of the poppet valve 28.
6 is rotatably supported by the casing 24, and a cam 38 provided on the cam shaft 36 presses against the biasing force of the spring 32 of the poppet valve 28 to open and close the valve passage 26. It is like this. As shown in FIG. 1, the camshaft 36 is synchronously rotatably connected to the eccentric shaft 5 by a timing belt or chain shown by 40 in the figure, and the poppet valve 28 is synchronized with the rotation of the eccentric shaft 5. Are opened and closed at a predetermined timing.

Next, the structure of the intake / exhaust system of the rotary piston engine will be described. As shown in FIG. 1, the air cleaner 4
A venturi portion 44 is provided in the intake passage 42 downstream of 0, and an air throttle valve 46 is provided downstream of the venturi portion 44. The air throttle valve 46 is driven to open and close by a step motor 48 as an actuator, and is provided with a position sensor 50 for detecting its opening. The downstream side of the intake passage 42 has two intake passages 42a,
42b, and the intake passages 42a and 42b are connected to the intake ports 6 and 6 of the cylinders F and R, respectively.
On the other hand, the exhaust port 52 formed in the rotor housing 1
Is connected to an exhaust passage 54, the exhaust passages 54, 54 of both cylinders F, R are merged into one exhaust passage 56, and an O ₂ sensor 58 for detecting an air-fuel ratio is provided in the exhaust passage 56.
Is provided. Further, the second hydrogen supply line 14 described above is connected to the intake passage 42. A downstream side of the second pressure regulator 18 of the hydrogen supply line 14 is linked to an accelerator pedal (not shown) depressed by the driver and a predetermined air-fuel ratio can be obtained according to the operating state of the engine. A hydrogen flow rate control valve 60 and a normally-closed solenoid valve 62 having two functions that are controlled as described above are provided, and the lower end portion of the valve is a venturi portion 4.
4 is connected. .

Reference numeral 70 denotes a controller. Various information such as engine load is input to the controller 70, and various signals are output based on the input information. Next, the fuel supply operation controlled by the controller 70 will be described. FIG. 3 is a diagram showing the conditions for switching the premixed injection of the gaseous fuel from the intake port 6 and the direct injection from the hydrogen injection port 7 in the first embodiment. As shown in FIG. 3, in the low load operating range where the engine speed is low and the squish flow is weak, such as the idle state and the partial load state, the solenoid valve 20 provided in the first hydrogen supply line 12 is shown. Solenoid valve 62 installed in the second hydrogen supply line 14 while closing the
To open. As a result, the gaseous fuel is the hydrogen supply source 1.
From 0, a small amount of hydrogen gas that has been depressurized (low pressure) to a predetermined value via the second pressure regulator 18 is supplied into the intake passage 42, and finally from the intake port 6 into the working chamber 4 (combustion chamber). Is supplied to. In this way, in the low load state, the mixture state of the air-fuel mixture becomes good, the thermal efficiency is improved, and the fuel consumption performance is also improved. On the other hand, in the high load state, the solenoid valve 20 provided in the first hydrogen supply line 12 is opened and the solenoid valve 62 provided in the second hydrogen supply line 14 is closed, and then the compression is performed. Hydrogen injection valve 2 at the beginning of the process
2 is opened. As a result, in the gaseous fuel, a large amount of hydrogen gas, which has been depressurized (high pressure) from the hydrogen supply source 10 to a predetermined value via the first pressure regulator 16, is supplied from the hydrogen injection port 7 into the working chamber 4 (combustion chamber). Is supplied to. As described above, in the high load state, the output can be improved by directly injecting the hydrogen gas into the working chamber 4 of the engine.

Further, in the medium load operation range, that is, in the predetermined load operation range in which the load is between L ₁ and L ₂ , the premix injection of the gaseous fuel from the intake port 6 and the direct injection from the hydrogen injection port 7 are performed. I am trying to overlap and. In the first embodiment, the pressure regulator 18 for premixed fuel injection and the pressure regulator 1 for direct injection are provided.
Since 6 and 6 are provided independently, when direct injection is changed to premixed injection in the medium load operation region by overlapping and switching, even if fuel supply delay occurs in premixed injection, combustion is performed by direct injection. Since gaseous fuel is supplied to the room, it is possible to prevent a misfire due to a lean state. Further, since the pressure of the pressure regulator 18 is set relatively low for premix injection, a small amount of gaseous fuel can be controlled with high accuracy. On the other hand, since the pressure of the pressure regulator 16 for direct injection is set relatively high,
The required gaseous fuel can be secured accurately. As a result, an appropriate air-fuel ratio can be maintained. Next, a second embodiment of the present invention will be described with reference to FIG. This second
Regarding the embodiment, description of the same parts as those of the first embodiment described above will be omitted, and only different parts will be described.

In this embodiment, a single hydrogen supply line 80 is connected to the hydrogen supply source, a pressure regulator 82 is provided in the hydrogen supply line 80, and a hydrogen flow rate regulating valve 84 and hydrogen injection are provided. A valve 86 is provided.
The hydrogen supply line 80 is a first side for supplying hydrogen gas to the hydrogen injection port 7 on the downstream side of the hydrogen injection valve 86.
To a second hydrogen supply line 90 for supplying hydrogen gas to the intake port 6. The first hydrogen supply line 88 is provided with a normally closed solenoid valve 92, and the second hydrogen supply line 90 is provided with a normally closed solenoid valve 94 and a throttle valve having a function of making it difficult for hydrogen gas to flow. 96 are provided. Also in this embodiment, as in the first embodiment, by switching the solenoid valves 92 and 94 in the low load state and the high load state, respectively, in the low load state, the mixing state of the air-fuel mixture becomes good and the fuel consumption performance is improved. In addition to the improvement, the output can be improved in the high load state. In the medium load operation range, as in the first embodiment, as shown in FIG. 3, in the predetermined load operation range in which the load is between L ₁ and L ₂ , the premix injection of the gaseous fuel from the intake port 6 is performed. The direct injection from the hydrogen injection port 7 is made to overlap.

In the second embodiment, the solenoid valve 92 for switching between the direct injection and the premixed injection is the hydrogen injection valve 86.
It is provided further downstream. For this reason, the fuel supply by the direct injection and the fuel supply by the premix injection are performed in the same period in terms of timing, so that the fuel easily enters the combustion chamber. As a result, at the time of overlap, even if the fuel supply delay occurs in the premixed injection, the gaseous fuel is supplied into the combustion chamber by the direct injection, so that it is possible to prevent the misfire from becoming the lean state. Further, in the second embodiment, since the throttle valve 96 is provided in the second hydrogen supply line 92, the following effects are obtained. That is, the hydrogen fuel is directly injected from the hydrogen injection port 7 for a predetermined short period of the initial period of the compression process, so that the working chamber 4 is in a high pressure state. On the other hand, the intake port 6 is always open to the working chamber 4. As a result, fuel is more easily supplied from the intake port 6 than from the hydrogen injection port 7. However, by providing the throttle valve 96 in the second hydrogen supply line 92, it becomes difficult for hydrogen gas to flow in this line 92, and therefore the ease with which fuel enters the combustion chamber becomes similar. Therefore, at the time of the above overlap,
Furthermore, it becomes possible to effectively prevent the misfire due to the lean state.

On the other hand, the present invention is not limited to the rotary piston engine described above, but can be applied to a reciprocating engine. Hereinafter, a third embodiment in which the present invention is applied to a reciprocating engine will be described. FIG. 5 is an overall configuration diagram showing a third embodiment in which the present invention is applied to a reciprocating engine. In this embodiment, the above-described first embodiment applied to a rotary piston engine is applied to a reciprocating engine. Therefore, the same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. To do. The cylinder head 101 is formed with two intake ports 102, one exhaust port 103, and one hydrogen port 104 opening in the combustion chamber 105.
On 04, poppet valves 108 and 109 which are opened and closed by cams 106 and 107, respectively, are provided. In the high load operation range, the solenoid valve 20 provided in the first hydrogen supply line 12 is opened and the solenoid valve 62 provided in the second hydrogen supply line 14 is closed in the high load operation range, Hydrogen gas supplied from the hydrogen supply source 10 is supplied to the hydrogen port 104 through the first hydrogen supply line 12 and the hydrogen manifold 110,
The hydrogen is supplied directly into the combustion chamber 105 at a predetermined timing by a poppet valve 109 that opens and closes the hydrogen port 104 at a predetermined timing.

Further, in the low load region, the electromagnetic valve 20 provided in the first hydrogen supply line 12 is closed and the electromagnetic valve 62 provided in the second hydrogen supply line 14 is opened, so that a small amount of fuel is discharged. Hydrogen gas is the second hydrogen supply line 1
4 is supplied to the Venturi portion 44 of the intake passage 42, mixed with air in the intake passage 42, and the intake port 102.
To be supplied to.

[0019]

As described above, according to the present invention, the fuel pre-mixing means for directly feeding the gaseous fuel into the combustion chamber is used to pre-mix the gaseous fuel with the air at the intake port to supply the fuel to the combustion chamber. It is possible to prevent misfire due to a lean state when switching to the supply means and supplying the gaseous fuel to the engine.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a rotary piston engine showing a first embodiment of a fuel supply device for gaseous fuel of the present invention.

FIG. 2 is an enlarged cross-sectional view of a portion where the hydrogen injection valve of FIG. 1 is attached.

FIG. 3 is a diagram showing a mode of switching between premixed injection and direct injection.

FIG. 4 is an overall configuration diagram of a rotary piston engine showing a second embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a reciprocating engine showing a third embodiment of the present invention.

[Explanation of symbols]

 4 Working Chamber 6 Intake Port 7 Hydrogen Injection Port 10 Hydrogen Supply Source 12 First Hydrogen Supply Line 14 First Hydrogen Supply Line 16 First Pressure Regulator 17 Second Pressure Regulator 18 Hydrogen Flow Control Valve 20 Solenoid Valve 22 Hydrogen injection valve 42 Intake passage 60 Hydrogen flow rate control valve 62 Electromagnetic valve 80 Hydrogen supply line 82 Pressure regulator 84 Hydrogen flow rate control valve 86 Hydrogen flow rate control valve 88 First hydrogen supply line 90 First hydrogen supply line 92 Solenoid valve 94 solenoid valve 96 throttle valve 104 hydrogen port 105 combustion chamber

Front page continued (72) Inventor Hiroyasu Uchida No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Inventor Ichiho Doen No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Corporation ( 72) Inventor Yoshio Fujita 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (3)

[Claims] 1. A fuel supply device for a gas fuel engine, comprising a fuel premixing supply means for sucking a gaseous fuel into an intake port, mixing the gaseous fuel with air in advance, and supplying the gaseous fuel to a combustion chamber. Direct fuel supply means for direct supply and switching control for switching between these gas supply means by the fuel direct supply means to the gaseous fuel supply by the fuel premixing supply means in a predetermined load operating region by overlapping these supply means. Means and a gaseous fuel pressure regulator independently provided in the fuel premix supply means and the fuel direct supply means, respectively, the pressure of the gaseous fuel pressure regulator provided in the fuel premix supply means Is set lower than the pressure of the gaseous fuel pressure regulator provided in the direct fuel supply means. 2. A fuel supply device for a gas fuel engine, comprising a fuel premixing supply means for sucking a gaseous fuel into an intake port, mixing the gaseous fuel with air in advance, and supplying the gaseous fuel to the combustion chamber. Direct fuel supply means, timing setting means for setting fuel supply timing of the fuel premixing supply means and direct fuel supply means, and fuel provided in a predetermined load operation range downstream of the timing setting means. A fuel supply for a gas fuel engine, comprising: switching control means for switching the supply of the gaseous fuel by the direct supply means to the supply of the gaseous fuel by the fuel premixing supply means by overlapping these two supply means. apparatus. 3. The fuel supply device for a gas fuel engine according to claim 2, wherein the fuel premixing supply means has a throttle means downstream of the switching control means.