JPS6296769A - Fuel feeder for internl combustion engine - Google Patents

Abstract

PURPOSE:To prevent double feed of two kinds of fuels, in a system where a carburetor for feeding a liquid fuel and a mixer for feeding a gas fuel are arranged in an intake path, by executing switching of two kinds of fuels according to the gas fuel pressure. CONSTITUTION:In a system where a carburetor 10 for feeding a liquid fuel such as gasoline and a mixer 16 for feeding a gas fuel such as LPG in a pressure container 12 through a pressure regulator 14 are arranged in an intake path 20, a control valve (solenoid valve) 34 for opening/closing main nozzle 24 of the carburetor 10 is provided. While a cut-off valve 42 is arranged in the way of a high pressure pipe 40 inter communicating the pressure container 12 with the primary chamber 14b of the pressure regulator 14. When switching to the liquid fuel, said valve 42 is closed through operation of a changeover switch 48 and a fuel pump 30 is started while upon turning off a pressure switch 50 because of lower pressure in said chamber 14b than a predetermined level, the control valve 34 is de-energized and the main nozzle 24 is controlled to be opened.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a fuel supply system for an internal combustion engine, and in particular to an internal combustion engine that uses liquid fuel such as gasoline and gaseous fuel such as liquefied petroleum gas by appropriately switching between them. The present invention relates to a fuel supply device.

(Prior Art) Due to the depletion of petroleum resources, modern internal combustion engines tend to use more diverse fuels, such as liquid fuels such as gasoline and liquefied petroleum gases (L, P, etc.).

Gaseous fuels such as G) and the like are provided.

In this type of internal combustion engine, a vaporizer that mixes and atomizes liquid fuel and a mixer that mixes gaseous fuel and intake air are generally installed in the intake passage. There were technical issues when switching.

In other words, when switching fuels, if two types of fuel are supplied redundantly, not only will fuel be wasted;
The air-fuel mixture supplied to the internal combustion engine becomes overheated, and the internal combustion engine becomes inoperable.

In other words, the desired switching condition is for the one fuel in use to be almost completely discharged before the other fuel being switched to is smoothly supplied.

Therefore, as a fuel supply device that solves these problems and enables smooth fuel switching, for example, Japanese Patent Laid-Open No. 57
There is a device disclosed in Japanese Patent No.-18446.

In order to avoid duplication of fuel supply, the fuel supply system in the same issue requires that when switching from one state of use to the other, the fuel of the other is not immediately supplied at the same time as the switch is made, but is supplied after a predetermined period of time. The basic structure is a gas fuel supply consisting of a pressure vessel filled with gas fuel, a mixer installed in the supply passage of the internal combustion engine, and a pressure regulating device interposed between these. A system is shown in which a control valve provided between the secondary side of the pressure regulating device and the mixer is opened and closed in a delayed manner.

(Problems to be Solved by the Invention) However, the fuel supply device disclosed in the above-mentioned publication has the following drawbacks because the connection between the secondary side of the pressure regulating device and the mixer is opened and closed by a control valve.

In other words, in this type of device, the on-off valve is usually stacked close to the pressure vessel, and it is not economical to provide valves on both sides of the pressure regulating device.

Also, in vehicles equipped with this type of device, the pressure vessel is heavy, and the entire pressure vessel is heavy! In addition, the vibrator that connects the pressure regulator and the mixer has a large diameter in order to supply a large amount of gaseous fuel, and requires a large control valve to open and close it.

For this reason, there is a problem that the entire device becomes larger and the vehicle becomes heavier.

Furthermore, in the fuel supply device of the above-mentioned publication, when switching from one fuel supply state to the other fuel supply state, the predetermined time for delaying the other fuel supply is changed by constantly monitoring the operating state at the time of switching. Because of the necessity, there is a problem that the structure becomes complicated.

This invention was made in view of these problems, and its purpose is to provide a fuel for an internal combustion engine that allows smooth switching between two types of fuel without increasing the size of the device. The purpose is to provide a supply device.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a vaporizer for supplying liquid fuel and a mixer for supplying gaseous fuel in the intake passage of an internal combustion engine. The fuel supply device has a control valve that supplies and stops liquid fuel from the float chamber of the carburetor to the intake passage by opening and closing.

More specifically, the control valve directly or indirectly controls the supply of fuel (I) from the main nozzle of the carburetor to the intake passage.

Further, a pressure regulating device is provided between the mixer and the pressure vessel filled with gaseous fuel to sequentially reduce the pressure, and a pressure regulating device is provided between the pressure vessel and the pressure regulating device and operates in synchronization with the switching means. An on-off valve is provided.

Furthermore, when the pressure on the high-pressure side up to the on-off valve is lower than a set value on the upstream side of the low-pressure side of the gaseous fuel supply line that communicates the mixer and the pressure regulator, the float chamber The control valve is operated so that fuel is supplied from the air to the intake passage.

The pressure on the high pressure side is the pressure in the gaseous fuel supply path between the high pressure S of the pressure regulating device and the on-off valve.

(Function) In the fuel supply device having the above configuration, the control valve that opens and closes the vaporizer for liquid fuel supply is operated by the pressure on the side of the gaseous fuel supply system, so for example, when VJ is changed from gaseous fuel to liquid fuel, Liquid fuel is not supplied unless the pressure of the gaseous fuel supplied through the mixer is below a set value, and
On the other hand, when switching from liquid fuel to gaseous fuel, the pressure on the gaseous fuel side becomes equal to or higher than the set value at which supply preparation is completed.Then, the supply of liquid fuel is not stopped.

Therefore, the two types of fuel can be smoothly switched with almost no intermittent supply.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of a fuel supply state of an internal combustion engine according to the present invention.

The fuel supply device shown in the figure has a vaporizer 10 for supplying liquid fuel (gasoline) and a mixer 16 for supplying gaseous fuel (LPG) filled in a pressure vessel 12 via a pressure regulating device 14 for internal combustion. It is attached to the intake passage 20 of the barrier 18.

The carburetor 10 is provided between an air purifier 19 and an intake passage 20, and includes a venturi portion 22 that atomizes liquid fuel by the negative pressure of the internal combustion engine 18, and a venturi portion 22 that is supplied to the internal combustion engine 18. A comparison valve 23 for controlling fuel ili+, a main nozzle 24 opened to a venturi portion 22, a fuel tank 26, a fuel filter 28, and a fuel pump 30.
The main nozzle 24 is composed of a float chamber 32 that always stores a constant amount of liquid fuel that flows in through the main nozzle 32, and a fuel outflow passage 33 that communicates the float chamber 32 with the nozzle 24. It is directly opened and closed by a control valve 34 composed of a valve.

On the other hand, the mixer 16 is located further upstream of the choke valve 36 provided upstream of the venturi portion 22, and is connected to the two valves 14a of the pressure regulator 14 and the low pressure pipe 3.
8 and is connected in communication from the secondary 'J 14 a to the low pressure pipe 38. It forms the low pressure side of the gaseous fuel supply line connected to the mixer 16.

The pressure regulating device 14 has a spring material and a diaphragm as main components, and a primary chamber 14b (high pressure chamber) with a valve mechanism interposed therebetween.
and a secondary chamber 14a (low pressure chamber), and are configured such that the pressure decreases in the order of 1 digit 14b and secondary 'J14a.

A number 14b of the pressure regulating device is connected to the pressure vessel 12 through a high pressure pipe/IO for supplying gaseous fuel, and a cut-off valve 4 is located in the middle of the high pressure pipe 40 to open and close it.
2 and d3 are interposed, and these form the high pressure side of the gaseous fuel supply system.

This cut-off valve 42 has been conventionally provided in this type of device, constitutes the on-off valve of the present invention, and is operated by a changeover switch 48 connected in series with a battery 44 and a starting switch 4G. One contact of the changeover switch 48 is connected to the fuel pump 30.

In addition, the single number 14b of the pressure regulating device 14 includes the primary ηi
A pressure switch 50 is installed that turns on when the pressure inside 141) becomes less than a set value, and the switch 50
One side is connected between the changeover switch 48 and the starting switch 46, and the other side is connected to the drive coil of the control valve 3/'I.

In the fuel supply system having the following configuration, for example, internal combustion (
1 engine 18 is driven by liquid fuel supplied through the vaporizer 10, and when the driver operates the changeover switch 48 to switch to driving by gaseous fuel, the operation of the changeover switch 48 causes the combustion engine 18 to When the pump 30 is stopped, the cutoff valve 42 is opened, and the gaseous fuel in the pressure vessel 12 flows into the primary chamber 14b in the pressure regulator 14 through the high pressure pipe 40.

In this state, the supply of liquid fuel from the main nozzle 24 has not yet been stopped.

Then, when the pressure inside the number 14b increases and exceeds the set value, the pressure switch 50 is turned on, and the pressure switch 50 is turned on from the battery 414 via the start switch 46.
．． The circuit leading to the control valve 34 causes the control valve 34 to operate;
The main nozzle 24 of the carburetor 10 is closed to immediately stop the supply of liquid fuel to the intake passage 20.

Also, almost at the same time as the pressure switch 50 is activated, gaseous fuel flows into the secondary chamber 14a from the number 14b of the pressure regulator 14, reaches the mixer 16 via the low pressure bypass 138, and air purifier 19. The mixed air is mixed with air taken in from the air and is supplied to the intake passage 20.

Therefore, in this case, until the gaseous fuel supply type seedlings are prepared, liquid fuel is supplied from the vaporizer 10,
When the pressure in the primary Y14b rises and reaches quasi (-6), the main nozzle 24 is closed to prevent the occurrence of a blank period between the flat Fi supply and the supply of the fuel rI.

On the other hand, when switching to the use of liquid fuel while using gaseous fuel 11, the switch 7'I8 can be operated to
Off valve 42 is closed and fuel pump 30 is started.

The control valve 23 that closes the main nozzle 24 of the carburetor 10 by the switching operation is not immediately opened due to this,
Gaseous fuel is consumed via the mixer 16 and the pressure regulator 1
When the pressure in the 4-1 feeding chamber 14b decreases and becomes less than the set value, the pressure switch 50 is turned off, the circuit of the control valve 23 is opened, and as a result, the main nozzle 24 is opened.

As a result, liquid fuel flows from the main nozzle 24 into the intake passage 2.
0.

Also in this case, the main nozzle 24 of the carburetor 10 is opened after the fuel in the gaseous fuel supply line from the two feed chambers 14a of the pressure regulator 14 to the mixer 16 is released.
Redundant supply of two types of fuel hardly occurs.

Note that the connection point of the pressure switch 50 in the above embodiment on the battery 44 side may be provided between the changeover switch 48 and the fuel pump 30, as shown by the two-dot chain line in FIG.

FIG. 2 shows a second embodiment of the fuel supply system for an internal combustion engine according to the present invention, and only its features will be described below.

That is, in this embodiment, an opening +Fa is provided on the upstream side of the venturi portion 22 on the upstream side of the intake passage 20 that communicates the float chamber 32 of the carburetor 10 and the main nozzle 24.
The main nozzle 24 is indirectly controlled by opening and closing the air bleed 54 provided with the air bleed 52 by the control valve 34. When the front end 52 of the air bleed 54 is closed by the control valve 34, the first
As in the embodiment, the float chamber 32 and the fuel outflow passage 3
Liquid fuel is supplied to the intake passage 2 from the main nozzle 24 via the
0.

On the other hand, when the opening @i52 of the air bleed 54 is opened by the operation of the control valve 34, air flows into the main nozzle 24 through the air bleed 54, and the supply of liquid fuel is stopped.

Therefore, in this embodiment, the pressure switch 50 that operates the control valve 34 is turned on when the pressure in the first feeding chamber 14b of the pressure regulator 14 becomes less than the set value, and turned off when the predetermined pressure exceeds the set value. In this case, the same effect as in the first embodiment can be obtained.

FIG. 3 shows a third embodiment of the fuel supply system for an internal combustion engine according to the present invention, and only its features will be described below.

In the third embodiment shown in the figure, the main nozzle 24 of the carburetor 10 is opened and closed by an electrically operated control valve 34 in the first and second embodiments, whereas this is operated by a spring. and a diaphragm, and the working chamber of the diaphragm and the primary arm 14b of the pressure regulating device 14 are connected to each other by a connecting pipe 56.
The pressure from the primary to 14b of the pressure regulator 14 operates the direct control valve 34'.

In this configuration as well, the main nozzle 24 is opened and closed by the operation of the control valve 34-, and the same effect as in the above embodiment can be obtained, and liquid and gaseous fuel can be smoothly supplied without redundant supply. The pressure switch 50, which is activated by the pressure in the feeding chamber 14b, is not required, which simplifies the configuration and reduces the number of parts.

In the above embodiment, the carburetor 10 is of a so-called expropriation type, which is equipped with a plurality of low-speed d5 and high-speed venturi parts 22, but the implementation of the present invention is not limited to this. It may be a normal single-hulled type.

Furthermore, the installation location of the pressure switch 50 in the first and second embodiments and the location that communicates with the operating chamber of the diaphragm of the control valve 34- in the third embodiment are not limited to the first sending chamber 14b of the pressure regulating device 14. , it may be between the first sending chamber 14b of the pressure regulating device 14 and the cut-off valve 42.

(Effects of the Invention) As explained above in detail in the practical IA example, in the fuel supply system for an internal combustion engine according to the present invention, two types of fuel that can be arbitrarily switched can be switched without overlapping and without overlapping the blank period. It can be supplied smoothly without any trouble.

In addition, the liquid fuel supply from the vaporizer is directly or indirectly controlled by the high-pressure side pressure up to the on-off valve in the gaseous fuel supply line, so the conventional on-off valve can be used as is. Moreover, there is no need to install a large control valve on the low pressure side of the pressure regulating device, which prevents the entire device from becoming larger and the vehicle from becoming heavier.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a fuel supply device according to the present invention, FIG. 2 is a sectional view of main parts showing a second embodiment,
FIG. 3 is a sectional view of a main part showing a third embodiment. 10... Carburizer 12... Pressure vessel 14... Pressure regulator 16...
Mixer 18... Internal combustion engine 20...
...Intake passage 24...Main nozzle 32...
...Float chamber 34.3/l -...Control valve patent applicant Mazda Motor Corporation agent Patent attorney - Kensuke Shiro
Patent Attorney Masatoshi Matsumoto Figure 2 1q Zudo Figure 3 Q

Claims (1)

[Claims] In a fuel supply device that includes a vaporizer for liquid fuel supply and a mixer for gaseous fuel supply in an intake passage of an internal combustion engine, and has a means for appropriately switching between them, A control valve that supplies and stops fuel;
A pressure regulating device is provided between the mixer and the pressure vessel filled with the gaseous fuel, and an on-off valve that operates in synchronization with the switching means is provided between the pressure vessel and the pressure regulating device. , when the pressure on the high-pressure side upstream of the low-pressure side of the gaseous fuel supply line that communicates the pressure regulator and the mixer, up to the on-off valve, is less than the set value, air is taken in from the float chamber. A fuel supply device for an internal combustion engine, characterized in that the control valve is operated so that fuel is supplied to the passage.