JP2001050115A - Shape of injector port for gas fuel engine - Google Patents

Abstract

[PROBLEMS] To provide a shape of an injector port of a gaseous fuel engine for uniformly mixing natural gas as fuel and intake air. SOLUTION: A fuel outlet 20a for ejecting natural gas as fuel injected from an injector 4 is formed on an inner wall surface 3a of each intake pipe 3, and a fuel injection surface 4a of the injector 4 is moved from a fuel outlet 20a to a predetermined position. The injector port 20 was formed at a position having a distance, and the injector port 20 was formed such that the cross-sectional area gradually decreased from the position of the fuel injection surface 4a toward the position of the fuel outlet 20a. With this configuration, the natural gas flow injected from the injector 4 is accelerated inside the injector port 20 and
The natural gas and the intake air can be uniformly mixed by colliding the ejected natural gas with the intake air flow because the natural gas is ejected from a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the shape of an injector port of a gas fuel engine, and more particularly to an injector port of a gas fuel engine for uniformly mixing natural gas as fuel and intake air. Regarding the shape.

[0002]

2. Description of the Related Art Conventionally, compressed natural gas (CNG) has been widely used as a fuel for an internal combustion engine. However, the use of compressed natural gas (CNG) has been reduced with the development of gasoline engines and diesel engines. However, in recent years, compressed natural gas has once again attracted attention as a fuel for internal combustion engines due to increased interest in the environment and energy, and has been used to improve exhaust gas purification, fuel consumption rate, starting performance and output performance, etc. For this reason, the injection system is often used in compressed natural gas engines.

FIG. 7 and FIG. 8 show an embodiment of a conventional compressed natural gas engine, in which compressed natural gas filled in a CNG cylinder 51 is supplied to a predetermined location by a regulator 53 provided in a gas pipe 52. The pressure is reduced to the pressure and flows into the fuel distribution pipe 54, and each cylinder 55
Each intake pipe 57 is distributed to an injector 56 provided therein, and the injector 56 injects each intake pipe 57 into intake air flowing toward the combustion chamber 58. As shown in FIG. 7, the fuel distribution pipe 54 is provided with a fuel pressure sensor 60 and a fuel temperature sensor 61 connected to an interface of an ECU (Electronic Control Unit) 59 so that the gas pressure and the gas temperature can be controlled. The natural gas flow that changes accordingly is EC
U59 is controlled by correcting the fuel injection time of the injector 56 according to the signals of the respective sensors 60 and 61. After the intake air is purified by the air cleaner 62, the flow rate of the intake air is adjusted by the throttle valve 63, and the intake air flows into each intake pipe 57. In addition, EC
The interface of U59 includes an intake pressure sensor 64,
A throttle sensor 65, a water temperature sensor 66, and a crank angle sensor 67 are connected, and the ECU 59 optimally controls the state of the engine according to signals from these sensors.

By the way, natural gas is excellent in ignitability in a lean region, and a stable ignitability can be obtained by uniformly mixing natural gas as a fuel and intake air. As shown in FIG. 8, in an engine using natural gas as a fuel, specific gravity is smaller than air since methane is a main component, and as shown in FIG.
6 tends to collect above the intake port 68 and the intake air below the natural gas,
It was difficult to mix natural gas and air uniformly. Further, a mixture of natural gas and intake air forms a combustion chamber 58.
The natural gas and the intake air were mixed uniformly by forming a long inflow path before flowing into the
It was supposed to worsen the responsiveness of the engine.

Therefore, in a gaseous fuel engine using natural gas as a fuel, the intake system is injected into the intake port downstream of the throttle valve of the intake pipe of each cylinder of the engine in a direction opposing the main flow of intake air. Japanese Utility Model Laid-Open Publication No. Hei 6-80825 discloses that an injector is provided which forms an outlet and injects fuel from a fuel injection port only in an intake stroke of a cylinder. According to this intake system, a natural gas as a fuel is jetted against the main flow of the intake air to generate a drift, and as a result, a uniform mixture is obtained by generating a tumble in the combustion chamber. .

However, in the above-described intake system, a turbulence is generated in the combustion chamber by causing a drift in the intake flow due to the pressure of natural gas injection. There was a risk of anomalies. Further, since the fuel injection port is formed in the intake port, it is necessary to newly manufacture a mold for the cylinder head, which has a problem that the cost is high.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and is intended to eject natural gas as a fuel having a high flow rate from a fuel ejection port formed on a wall surface inside an intake pipe. Provided is a shape of an injector port of an engine for gaseous fuel, in which natural gas and intake air are uniformly mixed.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a fuel injection port is provided on the inner wall surface of each intake pipe on the downstream side of a throttle valve. In the shape of an injector port of a gas fuel engine in which an injector that injects natural gas as fuel only in the intake stroke of the engine is provided at the fuel injection port, the fuel injection surface of the injector is defined by the fuel injection port and a predetermined value. The fuel cell system is characterized in that a projection is formed on the combustion chamber side wall surface between the fuel injection surface and the fuel injection port by being installed with a distance.

With this configuration, natural gas as fuel injected from the fuel injection surface of the injector is
Since the flow velocity is accelerated along the convex portion formed on the combustion chamber side wall surface of the injector port and is ejected from the fuel injection port, the natural gas and the intake air flow can collide with each other. And the intake air can be uniformly mixed.

[0010] The invention according to claim 2 of the present invention is characterized in that the convex portion is formed such that the cross-sectional area of the injector port gradually decreases from the fuel injection surface of the injector toward the fuel injection port. I do.

With this configuration, the flow rate of the natural gas as fuel ejected from the fuel ejection port is accelerated, so that the natural gas and the intake air can be uniformly mixed.

According to a third aspect of the present invention, a fuel injection port is formed on a wall surface of a combustion chamber, and natural gas is injected into the fuel injection port only as fuel during a compression stroke of the engine. In the shape of the injector port of the gaseous fuel engine provided with the injector as described above, the fuel injection surface of the injector is provided at a position having a predetermined distance from the fuel injection port formed on the wall of the combustion chamber, and the inside of the injector port is provided. The projection is formed on the wall surface in a direction opposite to the direction in which air is compressed in the compression stroke.

[0013] With this configuration, the natural gas as fuel injected from the injection surface of the injector follows the protrusion protruding in the direction opposite to the direction in which air is compressed in the compression stroke of the injector port. In this way, the flow velocity is accelerated and the fuel gas is ejected from the fuel outlet, so that the natural gas and the intake air flow can collide with each other, and the natural gas and the intake air can be uniformly mixed.

According to a fourth aspect of the present invention, the projection is formed such that the cross-sectional area of the injector port gradually decreases from the fuel injection surface of the injector toward the fuel injection port. I do.

With this configuration, the flow rate of the natural gas as fuel injected from the fuel injection port formed on the combustion chamber wall surface is accelerated, so that the natural gas and the intake air are uniformly mixed. Can be.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. First, the outline of the gas fuel engine of the present embodiment will be described. The gaseous fuel engine 1 of the present embodiment uses compressed natural gas (CNG) as a fuel, and as shown in FIG.
The compressed natural gas filled in the G container 2 is suctioned by a CNG injector 4 (hereinafter simply referred to as an injector) provided in each intake pipe 3 to flow the intake pipe 3 toward the combustion chamber 5 (see FIG. 1). By injecting the natural gas, natural gas and air are mixed.

Next, compressed natural gas as fuel is injected into the injector.
The configuration for supplying to the ejector 4 will be described. CNG container
2 compressed natural gas (200 kg / c gauge pressure)
m^Two) Is a high-pressure reducing valve which is purified by the filter 6 and
7 to the specified pressure (3 kg / cm ^TwoDepressurized to fuel
Injector 4 provided in each intake pipe 3 by distribution pipe 8
It is structured to be distributed to. In addition, the injector 4
The ECU (electronic control not shown) indicates the fuel injection timing.
Device), fuel only during the intake stroke of the engine 1
It is controlled to inject natural gas. Burning
A fuel temperature sensor 9 and a fuel pressure sensor
A fuel supply 10 is provided, depending on the fuel temperature and the fuel pressure.
The changing fuel flow rate is determined by the ECU (electronic control unit).
Based on the detection signals of the temperature sensor 9 and the fuel pressure sensor 10,
To correct the fuel injection time of the injector 4 based on
More controlled.

As shown in FIG. 2, the intake system for inhaling the outside air is connected to each intake port 13 of the engine 1 by adjusting the flow rate of the intake air purified by the air cleaner 11 by the throttle valve 12. It is configured to flow into each intake pipe 3. Reference numeral 14 denotes a compressed natural gas filling port, reference numeral 15 denotes a fuel filling valve, reference numeral 1
Reference numeral 6 denotes a check valve, and reference numeral 17 denotes a main stop valve. Further, the code 1
Reference numeral 8 denotes a remaining pressure sensor, which has a structure in which the remaining pressure of the CNG container 2 is displayed on a pressure gauge 19 in the driver's seat.

Next, the shape of the injector port 20 of the gas fuel engine according to the present embodiment will be described.
As shown in FIG. 1 and FIG. 3, the injector port 20 of the present embodiment has a throttle valve 12 (see FIG. 2).
A fuel outlet 20a for discharging natural gas injected from the injector 4 into the intake pipe 3 is formed on a wall surface 3a inside the intake pipe 3 and provided above the intake pipe 3 on the downstream side. The fuel injection surface 4a is configured to be installed at a position having a predetermined distance (L in FIG. 1) from the fuel injection port 20a. The injector port 20 has a combustion chamber 5 inside the injector port 20.
A convex portion 21 (hatched portion in FIGS. 1 and 3) is provided on the side wall surface 20b, and the convex portion 21 is provided in FIGS.
As shown in FIG. 3, the cross-sectional area of the injector port 20 is the position of the fuel injection surface 4a of the injector 4 (cross-section AA in FIG. 3).
4 and the position of the fuel injection port 20a from FIG.
4 and a portion c) of FIG. 4. It should be noted that the cross section of the injector port 20 is not limited to the shapes shown in FIGS. 4A, 4B, and 4C, and as shown in FIG. From the position of the fuel injection surface 4a (FIG. 5A) to the position of the fuel injection port 20a (FIG. 5C).
The protrusion 21 may be formed so as to gradually decrease toward.

In such a configuration, the action of the shape of the injector port of the gas fuel engine according to the present embodiment will be described. In the engine for gaseous fuel according to the present embodiment, as shown in FIG. 3, in the intake stroke of the engine 1, an ECU (not shown) in which fuel injection timing is added to intake air flowing toward the combustion chamber 5 through each intake pipe 3. Natural gas as fuel controlled by the (electronic control device) is injected from the fuel injection surface 4 a of the injector 4. As shown in FIG. 1, the natural gas injected from the injector 4 has a cross-sectional area of the fuel injection surface 4 a of the injector 4.
When flowing through the injector port 20 formed so as to gradually decrease from the position (section AA in FIG. 3) to the position of the fuel outlet 20a (section CC in FIG. 3), the flow velocity is accelerated. Then, the fuel is ejected from the fuel ejection port 20a.

Therefore, by forming the cross-sectional area of the injector port 20 so as to be gradually reduced, the natural gas flow injected from the injector 4 is accelerated inside the injector port 20 and is jetted from the fuel jet port 20a. The natural gas collides with the intake air flowing into each intake pipe 3 toward the combustion chamber 5, so that the natural gas as the fuel and the intake air can be uniformly mixed. In addition, since natural gas as fuel and intake air are mixed without forming a long mixture flow path to obtain a uniform mixture, a uniform mixture is obtained without impairing responsiveness. be able to. In addition, injector port 2
In No. 0, since the fuel injection port 20a is formed on the wall surface 3a inside the intake pipe 3, the cylinder head of the engine 1 can be shared with other engines, and it can be manufactured at low cost.

Next, the shape of an injector port of a gas fuel engine according to another embodiment will be described. Note that portions having the same configuration as the gaseous fuel engine of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 6, the shape of an injector port of a gas fuel engine according to another embodiment relates to a direct fuel injection type gas fuel engine in which natural gas as fuel is directly injected into a combustion chamber 5. It is. The injector port 20 has a fuel injection port 20a formed on a wall surface 5a of the combustion chamber 5 for injecting natural gas as a fuel injected from the injector 4 into the combustion chamber 5 to burn the fuel injection surface 4a of the injector 4. It is configured to be installed at a position at a predetermined distance (L in FIG. 6) from the fuel injection port 20a toward the direction of the chamber 5. In addition, as shown in FIG.
A projection 21 (hatched portion in FIG. 6) is provided on a wall surface 20 b inside the combustion chamber 5 so as to project in a direction opposite to a direction in which the intake air inside the combustion chamber 5 is compressed in the compression stroke of the engine 1. The protrusion 21 is formed such that the cross-sectional area of the injector port 20 gradually decreases from the position of the fuel injection surface 4a of the injector 4 toward the position of the fuel outlet 20a. Note that the injector 4 injects natural gas as fuel only in the compression stroke of the engine 1,
The fuel injection timing is controlled by an ECU (electronic control unit) not shown. Note that in FIG.
Reference numeral 2 denotes a piston, and reference numeral 23 denotes a spark plug.

In such a configuration, the operation of the injector port shape of the gas fuel engine according to another embodiment will be described. In the engine for gaseous fuel according to another embodiment, as shown in FIG. 6, in the compression stroke of the engine 1, the intake air compressed in the combustion chamber 5 includes:
Natural gas as fuel whose fuel injection timing is controlled by an electronic control unit (ECU) (not shown) is injected from a fuel injection surface 4 a of the injector 4. Then, as shown in FIG. 6, the natural gas injected from the injector 4 has an injector port 20 formed such that its cross-sectional area gradually decreases from the position of the fuel injection surface 4a of the injector 4 toward the position of the fuel injection port 20a. , The flow velocity is accelerated and jetted from the fuel jet port 20a.

Therefore, by forming the cross-sectional area of the injector port 20 so as to gradually decrease, the flow rate of the natural gas injected from the injector 4 is accelerated inside the injector port 20 and is jetted from the fuel jet port 20a. By colliding the natural gas with the intake air of the combustion chamber 5 which is pushed up by the piston 22 rising in the compression stroke of the engine 1, the natural gas as the fuel and the intake air can be uniformly mixed. In addition, a compressed natural gas engine has high ignitability in a lean region if the air-fuel mixture is uniform.Therefore, by mixing natural gas and intake air uniformly, a direct fuel injection type engine using gasoline as fuel is used. It is not necessary to form a rich atmosphere around the ignition plug 23 as in the above.

[0025]

According to the first aspect of the present invention, the fuel injection port is provided on the inner wall surface of each intake pipe, and the fuel of the injector is located at a predetermined distance from the fuel injection port. An injector port is formed to provide an injection surface, and a convex portion is provided on the combustion chamber side wall of the injector port, so that the flow rate of natural gas as fuel injected from the fuel injection surface of the injector is reduced by the flow rate of the injector port. The natural gas and the intake air are accelerated along the convex portion and collide the accelerated natural gas flow with the intake air flowing toward the intake chamber toward the combustion chamber, without impairing the responsiveness of the engine. It can be mixed uniformly. Further, since the injector port is provided in each intake pipe on the downstream side of the throttle valve, the cylinder head can be shared with another engine, and the production can be performed at low cost.

According to the second aspect of the present invention, in the first aspect of the present invention, the convex portion is formed such that a cross-sectional area of the injector port is changed from a fuel injection surface position of the injector to a fuel injection position. The natural gas flow injected from the fuel injection surface of the injector is accelerated and ejected from the fuel injection port, so that the natural gas as fuel and the intake air are evenly mixed. Can be done.

According to the third aspect of the present invention, the fuel injection port is provided on the wall surface of the combustion chamber, and the fuel injection surface of the injector is located at a predetermined distance from the fuel injection port. The injector port is formed so as to be installed, and the injector port is provided with a projection projecting in a direction opposite to the direction in which the intake air is compressed in the compression stroke of the engine, so that the fuel is injected from the fuel injection surface of the injector. The flow rate of the natural gas as fuel is accelerated along the convex portion of the injector port, and the accelerated natural gas flow collides with the intake air compressed in the compression stroke, whereby natural gas and intake air are separated. Uniform mixing can be achieved, and there is no need to form a rich atmosphere around the spark plug as in a direct fuel injection type engine using gasoline as fuel.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the projecting portion is formed such that the cross-sectional area of the injector port is changed from the fuel injection surface position of the injector to the fuel injection position. The natural gas injected from the fuel injection surface of the injector is accelerated and ejected from the fuel injection port, so that the natural gas as fuel and the intake air are evenly distributed. Can be mixed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a shape of an injector port of a gas fuel engine according to the present embodiment.

FIG. 2 is an explanatory view schematically showing an engine for gaseous fuel according to the present embodiment.

FIG. 3 shows a state in which natural gas as a fuel whose flow velocity is accelerated is injected into intake air flowing toward an intake pipe toward a combustion chamber due to the shape of an injector port of the gas fuel engine according to the present embodiment. FIG.

4A and 4B are diagrams showing a cross-sectional shape of an injector port of the gas fuel engine according to the present embodiment, wherein FIG. 4A is a cross-sectional view taken along a line AA in FIG. 3, FIG.
(C) is a cross section CC in FIG.

FIG. 5 is a view showing another example of the cross-sectional shape of the injector port in FIG. 4;

FIG. 6 is an explanatory view of a shape of an injector port of a gas fuel engine according to another embodiment.

FIG. 7 is an explanatory view schematically showing a conventional engine using compressed natural gas as a fuel.

FIG. 8 is an explanatory diagram showing a state where a conventional engine using compressed natural gas as fuel injects natural gas into intake air by an injector.

[Explanation of symbols]

 Reference Signs List 3 intake pipe 3a wall surface 4 injector 4a fuel injection surface 5 combustion chamber 5a wall surface 12 throttle valve 20 injector port 20a fuel injection port 20b wall surface 21 convex portion

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 21/02 F02M 21/02 S 301 301R 35/10 101 35/10 101E 69/00 69/00 350T

Claims (4)

[Claims] A fuel injection port is provided on an inner wall surface of each intake pipe on the downstream side of a throttle valve, and an injector is provided at the fuel injection port so as to inject natural gas as fuel only during an intake stroke of an engine. In the shape of the injector port of the gaseous fuel engine, the fuel injection surface of the injector is installed at a predetermined distance from the fuel outlet, and a combustion chamber between the fuel injection surface and the fuel outlet is provided. A shape of an injector port of an engine for gaseous fuel, wherein a convex portion is formed on a side wall surface. 2. The gas body according to claim 1, wherein the convex portion is formed such that a cross-sectional area of the injector port gradually decreases from the fuel injection surface of the injector toward the fuel injection port. Shape of injector port of fuel engine. 3. A fuel injection port is formed on a wall of the combustion chamber,
In the shape of an injector port of a gas fuel engine in which an injector that injects natural gas as fuel only in the compression stroke of the engine is provided at the fuel outlet, a fuel injection surface of the injector is formed on a wall surface of the combustion chamber. A gaseous fuel which is provided at a position having a predetermined distance from the fuel injection port, and which has a projection projecting in a direction opposite to a direction in which air is compressed in a compression stroke on an inner wall surface of the injector port. Shape of injector port for engine. 4. The gas body according to claim 3, wherein the projection is formed such that a cross-sectional area of the injector port gradually decreases from the fuel injection surface of the injector toward the fuel injection port. Shape of injector port of fuel engine.