JP2000018100A - Fuel supplying device for gaseous fuel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve startability at the time of low temperature especially by arranging a three-port solenoid valve in the vicinity of a fixed venturi in a gas mixer of a fuel supplying pipe, connecting the solenoid valve and an intake side of an engine to each other through a bypass passage, and leading gaseous fuel toward the bypass passage by switching the solenoid valve. SOLUTION: In the case where a starter switch 58 is turned on and a cooling water temperature detected by a water temperature sensor 60 exceeds not more than a predetermined water temperature, a three-port solenoid valve 70 is controlled in a current-carrying condition by control means 56, and a fuel supplying pipe 28 is connected to a bypass passage 72 side. In the case where engine rotating speed detected by an engine rotating speed sensor 62 exceeds not less than a setting rotating speed, the three-port solenoid valve 70 is controlled in a non-current-carrying condition by the control means 56, and the fuel supplying pipe 28 is connected to a fixed venturi 8 side of a gas mixer 10. The three-port solenoid valve 70 is switched and controlled only at the time of start by the control means 56, gaseous fuel is led to the bypass passage 72. Furthermore, at the time of acceleration, an auxiliary injector 48 is corrected and controlled.

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 gaseous fuel engine, and more particularly to a fuel supply device provided in a fuel supply pipe.
The port solenoid valve smoothly switches between the communication operation of the gas mixer to the fixed venturi side and the communication operation to the bypass passage side, smoothing the flow of gaseous fuel,
The present invention relates to a fuel supply device for a gaseous fuel engine that can improve the startability by guiding gaseous fuel to a bypass passage while ensuring a smooth flow of gaseous fuel.

[0002]

2. Description of the Related Art As a vehicle, there is a natural gas vehicle (NGV) which is a gas fuel vehicle equipped with an engine using CNG (compressed natural gas) which is a gas fuel.

In such a vehicle, a gas fuel container for storing gaseous fuel supplied to the engine is provided, an overflow prevention valve serving as a container base valve is provided in the gaseous fuel container, and a fuel supply valve is provided to the overflow prevention valve. One end of the pipe is connected and provided, and the other end of the fuel supply pipe is connected to the engine side. The fuel supply pipe is provided with a pressure sensor, a main stop valve, a pressure reducing valve, and the like. There is something.

The gaseous fuel in the gaseous fuel container is taken out by a fuel supply pipe, adjusted to a predetermined pressure and flow rate by a pressure reducing valve, mixed with air by a gas mixer, supplied to the engine from a fixed venturi, and supplied to a sub-injector. From the engine.

[0005] The gaseous fuel container is provided with an overflow prevention valve. The overflow prevention valve closes when the gas fuel consumed by the engine or more flows due to damage to the fuel piping system due to, for example, an accident, and shuts off the gas fuel from the gas fuel container.

As a fuel supply device for the gaseous fuel engine, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 6-264821. In the fuel supply device for a CNG engine disclosed in this publication, a regulator reduces the fuel pressure supplied from a CNG tank to a predetermined pressure, a mixer mixes the fuel reduced in pressure by the regulator and intake air, and a bypass passage is provided in the bypass passage. The fuel is introduced into the intake pipe downstream of the throttle valve by bypassing the secondary chamber and mixer, and the control valve opens and closes the bypass passage, controlling this control valve to open under special operating conditions to improve drivability. Let me.

[0007]

By the way, in a conventional fuel supply apparatus for a gaseous fuel engine, a general CNG is used.
2. Description of the Related Art An automobile employs a fuel supply system that uses a gas mixer that supplies gas from a fixed venturi to an engine after mixing gaseous fuel with air, and a sub-injector that directly injects gaseous fuel.

The output of the fixed venturi is reduced by restricting the intake air.

At this time, if the fixed venturi is formed large in order to increase the output, the flow velocity of the venturi portion is reduced in a low rotation speed region, particularly at the time of cranking. There is a disadvantage that the startability is deteriorated.

As a measure for solving the above-mentioned inconvenience, there is a method disclosed in Japanese Patent Application Laid-Open No. Hei 6-264821.

That is, Japanese Patent Laying-Open No. 6-264821 discloses that fuel is introduced into an intake pipe downstream of a throttle valve by a bypass passage that bypasses between a low-pressure reducing valve and a gas mixer provided with a fixed venturi. In addition, a control valve is provided, and the opening and closing control of the control valve improves the starting and acceleration performance.

However, according to the measure disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-264821, fuel is easily supplied at the time of starting. However, unless the engine speed is sufficiently increased, fuel is not discharged from the fixed venturi. There are inconveniences such as engine stall when the control valve is closed and poor connection between the bypass passage and discharge from the fixed venturi.

That is, if the fuel supply from the main system as well as the fuel supply from the bypass system is not sufficiently performed, a smooth start cannot be performed, and improvement has been desired.

[0014]

In order to eliminate the above-mentioned disadvantages, the present invention provides a gaseous fuel container for storing gaseous fuel, and a gaseous fuel container connected to an overflow prevention valve. One end of the fuel supply pipe is connected to the flow prevention valve, and the other end of the fuel supply pipe is connected to a gas mixer having a fixed venturi of an engine mounted on a vehicle. In a fuel supply device provided with a stop valve, a fuel pressure sensor, and a pressure reducing valve, a three-port solenoid valve is provided near the fixed venturi of the gas mixer in the middle of the fuel supply pipe, and the three-port solenoid valve and a throttle valve of the engine are provided. A bypass passage communicating with an intake system on the downstream side is provided, and control means for switching the three-port solenoid valve to guide gaseous fuel to the bypass passage side is provided. To.

A gas fuel container for storing gaseous fuel is provided, and an overflow prevention valve is connected to the gaseous fuel container.
One end of the fuel supply pipe is connected to the overflow prevention valve and the other end of the fuel supply pipe is connected to a gas mixer having a fixed venturi of an engine mounted on a vehicle, and provided in the middle of the fuel supply pipe. In a fuel supply device provided with a main stop valve, a fuel pressure sensor, and a pressure reducing valve, a branch pipe branching from a fuel supply pipe downstream of the pressure reducing valve is provided, and the branch pipe is provided downstream of a throttle valve of the engine. A three-port solenoid valve is provided in communication with a sub-injector arranged in the intake system on the side of the gas supply pipe, near the fixed venturi of the gas mixer in the middle of the fuel supply pipe, and is provided between the three-port solenoid valve and the throttle valve of the engine. A bypass passage communicating with the intake system on the downstream side is provided, and only when the engine is started, the three-port solenoid valve is switched and controlled to guide gaseous fuel to the bypass passage. During acceleration, characterized in that a control means for correcting control the supply amount of gaseous fuel by operating the sub-injector while.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION
The three-port solenoid valve smoothly switches between the operation of communicating the gas mixer to the fixed venturi side and the operation of communicating to the bypass passage side, thereby smoothing the flow of the gaseous fuel and ensuring the smooth flow of the gaseous fuel. For example, the gaseous fuel is guided to the side of the bypass passage at the time of starting, and the situation where the flow velocity of the fixed venturi is low and the gaseous fuel is difficult to be discharged is eliminated, and the startability is improved.

Further, the three-port solenoid valve smoothly switches between the operation of communicating the gas mixer to the fixed venturi and the operation of communicating to the bypass passage, so that the flow of gaseous fuel is smooth and the control means is controlled at the time of starting. By 3
Controlling the switching of the port solenoid valve to control the flow of gaseous fuel to the bypass passage side, ensuring a smooth flow of gaseous fuel, eliminating the situation where the flow rate of the fixed venturi was slow, and it was difficult to discharge gaseous fuel, and starting In addition, at the time of acceleration, the control means operates the sub-injector to perform correction control of the supply amount of gaseous fuel, and corrects the supply amount of gaseous fuel supplied to the engine by the gaseous fuel from the sub-injector, The operating condition of the engine is maintained well.

[0018]

An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention.

First, a fuel supply device of a gaseous fuel engine employing a fuel supply system having a gas mixer provided with a fixed venturi and a sub-injector will be described.

In FIG. 2, reference numeral 2 denotes a fuel supply device for a gaseous fuel engine, and reference numeral 4 denotes a CNG mounted on a vehicle (not shown).
The engine is supplied with a gaseous fuel such as (compressed natural gas).

The engine 4 is provided with a gas mixer 10 having an air cleaner 6 and a fixed venturi 8 in an intake system, a throttle body 12, and an intake manifold 14. A throttle valve 18 is provided in the throttle body 12 in the middle of an intake passage 16, and an exhaust valve is provided. An exhaust manifold 20 is provided in the system, and an exhaust passage 22 is provided.

The gaseous fuel supplied to the engine 4 is
It is stored in the gaseous fuel container 24. The gaseous fuel container 24
An overflow prevention valve 26 called a container main valve or a safety valve is provided. The overflow prevention valve 26 closes when gaseous fuel consumed by the engine 2 or more flows due to damage to the fuel piping system due to, for example, an accident, and shuts off gaseous fuel from the gaseous fuel container 24. is there. In FIG. 2, two gas fuel containers 24 are provided in parallel.

The overflow prevention valve 26 has a fuel supply pipe 28
Are connected to each other. The other end of the fuel supply pipe 28 is connected to the gas mixer 10 of the engine 4. The fuel supply pipe 28 is provided with a main stop valve 30, a residual pressure sensor 32, a high pressure reducing valve 34, a pressure switch 36, and a low pressure reducing valve 38 in order from the gaseous fuel container 24 side.

The main stop valve 30 is a universal type solenoid valve, and is installed at a position closest to the gaseous fuel container 24 to secure the safety of the fuel supply system.

The high-pressure reducing valve 34 supplies gaseous fuel at an appropriate pressure and flow rate, for example, 200 kg / cm ² to 4 kg / cm ^2.
Adjust to reduce the pressure to ² .

[0027] The low pressure reducing valve 38, a gaseous fuel that has been depressurized by the pressure reducing valve 34 to 4 kg / cm ^2, to adjust in order to reduced pressure to the atmospheric pressure and 0.3 kg / cm ^2.

One end of a fuel filling pipe 40 is connected to a fuel supply pipe 28 adjacent to the gaseous fuel container 24. At the other end of the fuel filling pipe 40, a filling port 42 is provided. The filling port 42 is connected to a filling device (not shown) of a filling device when filling the gaseous fuel container 24 with gaseous fuel. The fuel filling pipe 40 is provided with a fuel filling valve 44 and a check valve 46 in order from the filling port 42 side.

The low pressure reducing valve 38 and the engine 4
The first fuel supply pipe 28-1 for the main system, the second fuel supply pipe 28-2 for the slow system, and the third fuel supply pipe 28 for the sub system -3.

That is, the first fuel supply pipe 28 for the main system
-1, communicates the low pressure reducing valve 38 with the gas mixer 10 and supplies gas fuel at atmospheric pressure to the fixed venturi 8.

Further, the second fuel supply pipe 28-
2 supplies 0.3 kg / cm ² of gaseous fuel to a slow system provided near the throttle valve 18 in the throttle body 12.

Further, a third fuel supply pipe 28-3 for the sub system is provided.
A low-pressure reducing valve 38 and a sub-injector 48 disposed in the intake system downstream of the throttle valve 18 of the engine 4. , And 0.3 kg / cm ² of gaseous fuel is supplied to the sub-injector 48.

In the middle of the exhaust passage 22 of the engine 4,
An oxygen sensor 50, a three-way catalyst 52, and a muffler 54 are provided sequentially from the upstream side.

As shown in FIGS. 1 and 2, the control means (CPU) 56 includes a main stop valve 30, a sub-injector 48, an oxygen sensor 50, a starter switch 58 for detecting a starting operation state, and A water temperature sensor 60 for detecting a cooling water temperature, an engine speed sensor 62 for detecting the engine speed, and a throttle opening sensor 64 for detecting the throttle opening of the throttle valve 18 are connected and provided.

The remaining pressure sensor 32 is connected to a pressure gauge 66 provided in a driver seat (not shown).

Further, the fuel supply device 2 of the gaseous fuel engine shown in FIG. 2 is provided with two pressure reducing valves, a high pressure reducing valve 34 and a low pressure reducing valve 38, as shown in FIG. A regulator (not shown) is provided and a single pressure reducing valve 68 is provided. In the pressure reducing valve 68, a high pressure chamber 68-1, a primary chamber 68-2, and a secondary chamber 68-3 are provided from the gas fuel container 24 side. You can also.

At this time, a 3-port solenoid valve 70 is provided near the fixed venturi 8 of the gas mixer 10 in the middle of the fuel supply pipe 28, and the 3-port solenoid valve 70 and the downstream side of the throttle valve 18 of the engine 4 are provided. A bypass passage 72 communicating with the intake system is provided, and the control means 56 controls the switching of the three-port solenoid valve 70 so that the gas fuel is guided to the bypass passage 72 side.

More specifically, the three-port solenoid valve 70 is
As shown in FIG. 1, the fuel supply pipe 28 is disposed in the middle of the first fuel supply pipe 28-1 for the main system and near the fixed venturi 8 of the gas mixer 10.

At the time of starting under predetermined conditions, the control means 56 turns on the universal type three-port solenoid valve 70 and connects the first fuel supply pipe 28-1 of the fuel supply pipe 28 to the bypass passage 72 side. When the set conditions are satisfied, the three-port solenoid valve 7
0 is de-energized, and control is performed so that the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the fixed venturi 8 side of the gas mixer 10.

The control means 56 determines whether the engine speed Ne is equal to or lower than the predetermined engine temperature Ne, which is a predetermined condition including the ON operation of the starter switch 58 and the predetermined water temperature t or less.
(Rpm) or more setting conditions.

That is, when the starter switch 58 is turned on and the cooling water temperature becomes equal to or lower than the predetermined water temperature t degrees, a predetermined condition is satisfied, and the three-port solenoid valve 70 is energized as shown in FIG. Is controlled so that the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the bypass passage 72 side, and the engine speed Ne is set to the set engine speed a.
(Rpm) or more, the set condition is satisfied,
The port solenoid valve 70 is de-energized, as shown in FIG.
Control is performed so that the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the fixed venturi 8 side of the gas mixer 10.

Here, the sub-injector 48 will be described. The control means 56 controls the switching of the three-port solenoid valve 70 only at the time of starting to control the three-port solenoid valve 70 to guide the gaseous fuel to the bypass passage 72 side. At the time of acceleration at which Ne becomes equal to or higher than the set engine speed a (rpm), the sub-injector 48 is operated to perform correction control of the supply amount of gaseous fuel.

Next, the operation will be described with reference to the control flowchart of FIG.

When the program of the control flowchart of the control means 46 is started (100), it is determined whether or not the starter switch 58 is ON (102).
I do.

If the determination (102) is NO, the process shifts to a process (110) in which a three-port solenoid valve (also referred to as a "three-port valve") 70 described later is de-energized, and End the program of the flowchart (11
2) In addition, if the determination (102) is YES, a determination (104) is made as to whether the cooling water temperature is equal to or lower than a predetermined water temperature t degrees.

If this determination (104) is NO, 3
The process shifts to the process (110) for turning off the port solenoid valve 70, the program of the control flowchart is ended (112), and if the determination (104) is YES, the 3-port solenoid valve 70 is turned on. (10
6).

That is, when the judgments (102) and (104) are YES, the predetermined condition is satisfied, and the control means 56 sets the three-port solenoid valve 70 to the energized state as shown in FIG. Control is performed so that the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the bypass passage 72 side.

After the process (106) for turning on the three-port solenoid valve 70, it is determined (108) whether the engine speed Ne is equal to or higher than the set engine speed a (rpm).

If the judgment (108) is NO, 3
The process returns to the process (106) for turning on the port solenoid valve 70, and if the determination (108) is YES, the 3-port solenoid valve 70 is turned off (110).

That is, when the determination (108) is YES, the set condition is satisfied, and the control means 56 sets the three-port solenoid valve 70 to the non-energized state, as shown in FIG. 28 first fuel supply pipe 28-
1 is controlled to communicate with the fixed venturi 8 of the gas mixer 10.

After the process (110) for turning off the three-port solenoid valve 70, the program of the control flowchart is ended (112).

That is, at the time of starting when predetermined conditions are satisfied, the three-port solenoid valve 70 is turned on and the fuel supply pipe 2 is turned on.
8, the first fuel supply pipe 28-1 is connected to the bypass passage 72 side, and the gaseous fuel is pulled by the intake pipe pressure to smooth the flow of the first fuel supply pipe 28-1 which is the main system passage.

When the set conditions are satisfied, the three-port solenoid valve 70 is de-energized, the communication to the bypass passage 72 is cut off, and the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the gas mixer 10. The gas fuel flowing in the first fuel supply pipe 28-1 is caused to flow to the fixed venturi 8 side of the gas mixer 10 by the inertia force by communicating with the fixed venturi 8 side.

The sub-injector 48 is operated by the control means 56 at the time of acceleration when the engine speed Ne becomes equal to or higher than the set engine speed a (rpm) to correct and control the supply amount of gaseous fuel.

Thus, the gas mixer 10 provided in the vicinity of the fixed venturi 8 of the gas mixer 10 in the middle of the fuel supply pipe 28 is provided.
By the port solenoid valve 70, the switching operation of the gas mixer 10 to the fixed venturi 8 side and the communication operation to the bypass passage 72 side can be smoothly switched, and the flow of gaseous fuel can be made smooth, which is practically advantageous. It is.

Further, at the time of starting under predetermined conditions, the control means 56 controls the switching of the three-port solenoid valve 70 so as to guide the gaseous fuel to the bypass passage 72 side, thereby ensuring a smooth flow of the gaseous fuel. In addition, the gaseous fuel can be guided to the bypass passage 72 side at the time of starting, so that the situation where the flow velocity of the fixed venturi 8 is low and the gaseous fuel is difficult to be discharged can be eliminated. Can improve.

Further, the control means 56 controls the three-port solenoid valve 70 to be in an energized state and to connect the first fuel supply pipe 28-1 of the fuel supply pipe 28 to the bypass passage 72 side when starting under predetermined conditions. At the same time, when the set conditions are satisfied, control is performed so that the three-port solenoid valve 70 is de-energized and the first fuel supply pipe 28-1 of the fuel supply pipe 28 is connected to the fixed venturi 8 side of the gas mixer 10. Accordingly, the three-port solenoid valve 70 is energized only at the time of starting under predetermined conditions, so that the startability can be reliably improved, and the three-port solenoid valve 70 is de-energized when the set conditions are satisfied. 70 can be avoided, and the reliability of control can be improved.

Further, the control means 56 determines a predetermined condition including the ON operation of the starter switch 58 and a predetermined water temperature t or lower, and a set condition where the engine speed Ne is equal to or higher than the set engine speed a (rpm). By having this, it is possible to accurately determine whether or not it is the time of starting, and if the predetermined value or the set value is changed, it can be used only for vehicles with different specifications, and versatility Can be large.

The control means 56 operates the sub-injector 48 to perform correction control of the gaseous fuel supply amount during acceleration when the engine speed Ne becomes equal to or higher than the set engine speed a (rpm). The amount of gaseous fuel supplied to the engine 4 by the gaseous fuel from the sub-injector 48 can be corrected, and the operating state of the engine can be maintained satisfactorily, which is practically advantageous.

It should be noted that the present invention is not limited to the above-described embodiment, and various application modifications are possible.

For example, in the embodiment of the present invention, the control means determines whether the starter switch 58 has been turned ON and the predetermined condition is equal to or lower than the predetermined water temperature t degrees, and the engine speed N
Although e has a set condition that is equal to or more than the set engine speed a (rpm), a configuration (SG1) in which an item indicating whether or not the engine is warmed up may be added to the set condition. .

Then, as shown in FIG. 6, after the determination (108) as to whether the engine speed Ne is equal to or higher than the set engine speed a (rpm) is YES, the engine is in a warm-up state. It is determined whether or not the three-port solenoid valve is not energized when the engine is cold, even if the engine speed exceeds the set engine speed at the time of extremely low temperature start. The smooth flow of gaseous fuel from the bypass passage side due to the pipe pressure can be maintained, and the warm-up can be performed efficiently.

In the embodiment of the present invention, the three-port solenoid valve 70 is provided near the fixed venturi 8 of the gas mixer 10 in the middle of the first fuel supply pipe 28-1 of the fuel supply pipe 28. Instead of the port solenoid valve 70,
A configuration using the negative pressure switching valve 82 (SG2) is also possible.

That is, as shown in FIG.
8, a negative pressure switching valve 82 is provided in the vicinity of the fixed venturi of the gas mixer in the middle of the first fuel supply pipe 28-1. In the negative pressure chamber 84 of the negative pressure switching valve 82, an intake pipe downstream of the throttle valve is provided. When pressure is applied, the diaphragm 86 is operated at the time of startup to move the valve body 88 and communicate with the bypass passage 72 as shown by the one-dot chain line in FIG.

Then, at the time of starting when the throttle opening is small, as shown by the one-dot chain line in FIG. 7, the valve can be connected to the bypass passage 72 by the negative pressure switching valve 82.
As shown by a thick black arrow in FIG. 7, gas fuel can be supplied to the engine using the bypass passage 72, and at the time of acceleration when the throttle opening becomes large and the intake pipe pressure weakens, as shown by the solid line in FIG. The biasing force of the spring 90 of the switching valve 82 makes it possible to communicate with the fixed venturi of the gas mixer, and as shown by the thick arrow in FIG. While starting the gaseous fuel, the gaseous fuel can be guided to the bypass passage 72 side at the time of starting, and the startability can be improved.

Further, in the embodiment of the present invention, the switching control is performed depending on whether the 3-port solenoid valve is energized or de-energized. However, when starting under predetermined conditions, the fuel supply pipe is connected to the fixed venturi side of the gas mixer. It is also possible to adopt a configuration (SG3) in which an opening / closing means for communicating with both the bypass passage side is provided.

For example, the fuel supply to the bypass passage is
The opening / closing means is opened and closed using a fixed value set in multiple stages such as large, medium and small to control the flow rate.

In this case, at the time of starting under predetermined conditions, the gas is supplied to both the fixed venturi side and the bypass passage side of the gas mixer, and the flow between the fixed venturi side and the bypass passage side of the gas mixer is related, and the smooth gas fuel is generated. Flow can be secured, and fine fuel control to the fixed venturi side of the gas mixer can be performed, which is practically advantageous.

Further, in the embodiment of the present invention,
Although the configuration of the fuel supply control of the gaseous fuel engine has been described, the configuration of the fuel supply control described above can be applied not only to the gaseous fuel engine but also to an engine using both gaseous fuel and gasoline or a gasoline engine. .

[0070]

As described in detail above, the present invention provides a gas fuel container for storing a gaseous fuel, is provided with an overflow prevention valve connected to the gaseous fuel container, and the overflow prevention valve is provided with a fuel supply pipe. One end is connected to the fuel supply pipe, and the other end of the fuel supply pipe is connected to a gas mixer having a fixed venturi of an engine mounted on a vehicle, and a main stop valve, a fuel pressure sensor, and a pressure reducing valve are provided in the fuel supply pipe. In the fuel supply device, a three-port solenoid valve is provided near the fixed venturi of the gas mixer in the middle of the fuel supply pipe, and the three-port solenoid valve is connected to the intake system downstream of the throttle valve of the engine. A passage is provided, and control means is provided for guiding the gaseous fuel toward the bypass passage by switching and controlling the 3-port solenoid valve, so that the fixed vent of the gas mixer is controlled by the 3-port solenoid valve. Can be performed switching between contact operation to contact operation and a bypass passage side to the Interview Li side smoothly,
The flow of the gaseous fuel can be smooth, which is practically advantageous. Further, by controlling the switching of the three-port solenoid valve by the control means so as to guide the gaseous fuel to the bypass passage side, the gaseous fuel is supplied to the bypass passage side at the time of starting, for example, while ensuring a smooth flow of the gaseous fuel. Thus, the situation where the flow rate of the fixed venturi is low and the gas fuel is difficult to be discharged can be eliminated, and the startability, particularly the startability at low temperatures, can be improved.

A gas fuel container for storing gaseous fuel is provided, and an overflow prevention valve is connected to the gaseous fuel container.
One end of the fuel supply pipe is connected to the overflow prevention valve, and the other end of the fuel supply pipe is connected to a gas mixer having a fixed venturi of an engine mounted on a vehicle. In a fuel supply device provided with a stop valve, a fuel pressure sensor, and a pressure reducing valve, a branch pipe branching from a fuel supply pipe downstream of the pressure reducing valve is provided, and the branch pipe is connected to an intake air downstream of a throttle valve of the engine. Provided in communication with the sub-injector provided in the system, and placed near the fixed venturi of the gas mixer in the middle of the fuel supply pipe.
A three-port solenoid valve is provided, a bypass passage is provided to connect the three-port solenoid valve to an intake system downstream of the throttle valve of the engine, and only when the engine is started, the three-port solenoid valve is switched to control the gas fuel to the bypass passage. And control means for correcting the supply of gaseous fuel by operating the sub-injector during acceleration, so that the three-port solenoid valve allows the gas mixer to communicate with the fixed venturi side and the bypass passage side to operate. Switching to the communication operation with the gaseous fuel can be performed smoothly, and the flow of the gaseous fuel can be made smooth, which is practically advantageous. Further, at the time of starting, by controlling the switching of the three-port solenoid valve by the control means so as to guide the gaseous fuel to the bypass passage side, a smooth flow of the gaseous fuel is ensured, the flow velocity of the fixed venturi is low, The situation where the fuel is hardly discharged can be resolved, and the startability can be improved. Further, the control means operates the sub-injector during acceleration to perform correction control of the supply amount of gaseous fuel, thereby correcting the supply amount of gaseous fuel supplied to the engine by the gaseous fuel from the sub-injector, Can be maintained satisfactorily, which is practically advantageous.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a fuel supply device of a gaseous fuel engine showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a fuel supply device of the gaseous fuel engine.

FIG. 3 is a flowchart for controlling a fuel supply device of the gaseous fuel engine.

FIG. 4 is a schematic diagram showing a state in which a 3-port solenoid valve is connected when energized.

FIG. 5 is a schematic diagram showing a state in which a 3-port solenoid valve is connected when power is not supplied.

FIG. 6 is a control flowchart of a fuel supply device of a gaseous fuel engine showing another first embodiment of the present invention.

FIG. 7 is a schematic enlarged view of a negative pressure switching valve showing another second embodiment of the present invention.

[Explanation of symbols]

 2 Fuel supply device for gaseous fuel engine 4 Engine 8 Fixed venturi 10 Gas mixer 12 Throttle body 14 Intake manifold 16 Intake passage 18 Throttle valve 20 Exhaust manifold 22 Exhaust passage 24 Gas fuel container 26 Overflow prevention valve 28 Fuel supply pipe 28-1 Main First fuel supply pipe for system 28-2 Second fuel supply pipe for slow system 28-3 Third fuel supply pipe for sub system 30 Main stop valve 32 Remaining pressure sensor 34 High pressure reducing valve 36 Pressure switch 38 Low pressure Pressure reducing valve 40 Fuel filling pipe 42 Filling port 44 Fuel filling valve 46 Check valve 48 Sub-injector 50 Oxygen sensor 56 Control means (CPU) 58 Starter switch 60 Water temperature sensor 62 Engine speed sensor 64 Throttle opening sensor 68 Pressure reducing valve 70 3 Port solenoid valve 72 Bypass passage

Claims (5)

[Claims] A gas fuel container for storing gaseous fuel is provided, an overflow prevention valve is connected to the gaseous fuel container, and one end of a fuel supply pipe is connected to the overflow prevention valve. The other end of the supply pipe is provided in communication with a gas mixer having a fixed venturi of an engine mounted on the vehicle,
In a fuel supply device provided with a main stop valve, a fuel pressure sensor, and a pressure reducing valve in the middle of the fuel supply pipe, a three-port solenoid valve is provided near a fixed venturi of a gas mixer in the middle of the fuel supply pipe. A bypass passage communicating between the engine and an intake system downstream of the throttle valve of the engine; and control means for switching the three-port solenoid valve to guide gaseous fuel toward the bypass passage. Fuel supply device for gaseous fuel engines. 2. The control means according to claim 1, wherein at a start of a predetermined condition,
The universal type three-port solenoid valve is energized to control the fuel supply pipe to communicate with the bypass passage, and when the set conditions are satisfied, the three-port solenoid valve is de-energized and the fuel supply pipe is deactivated. The fuel supply device for a gaseous fuel engine according to claim 1, wherein the fuel supply device is controlled so as to communicate with a fixed venturi side of the gas mixer. 3. The control device according to claim 1, wherein the control means includes
3. The fuel supply device for a gaseous fuel engine according to claim 2, wherein the fuel supply device has a predetermined condition including N operation and a predetermined water temperature or lower, and a set condition where the engine speed is equal to or higher than the set engine speed. 4. The fuel supply device for a gaseous fuel engine according to claim 3, wherein the control means adds an item of whether or not the engine is in a warm-up state to the set condition. 5. A gas fuel container for storing gaseous fuel is provided, an overflow prevention valve is connected to the gaseous fuel container, and one end of a fuel supply pipe is connected to the overflow prevention valve. The other end of the supply pipe is provided in communication with a gas mixer having a fixed venturi of an engine mounted on the vehicle,
In a fuel supply apparatus provided with a main stop valve, a fuel pressure sensor, and a pressure reducing valve in the middle of the fuel supply pipe, a branch pipe branched from a fuel supply pipe downstream of the pressure reduction valve is provided, and the branch pipe is connected to the engine. A three-port solenoid valve is provided near the fixed venturi of the gas mixer in the middle of the fuel supply pipe, in communication with a sub-injector disposed in the intake system downstream of the throttle valve. A bypass passage communicating with an intake system downstream of the throttle valve of the engine is provided, and only when the engine is started, the three-port solenoid valve is switched and controlled to guide gaseous fuel to the bypass passage. A fuel supply device for a gaseous fuel engine, further comprising control means for controlling the amount of supply of the gaseous fuel by operating the fuel cell.