JPH0724608Y2 - Engine fuel controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a fuel control device for an engine, and more particularly to a fuel control device for an engine adapted to use a liquid fuel such as gasoline and a gaseous fuel such as LPG by appropriately switching between them. It relates to the device.

(Prior Art) Conventionally, as described in JP-A-57-18446, for example, a device for supplying liquid fuel (gasoline) and a device for supplying gas fuel (LNG, LPG, etc.) are provided side by side. A hybrid engine is known in which a liquid fuel and a gas fuel are appropriately switched and used.

However, such a conventional hybrid engine is
As described in the above publication, a normal vaporizer equipped with a choke valve for supplying liquid fuel is used, and a mixer for supplying gaseous fuel is provided on the upstream side of the vaporizer choke valve. When closed, gaseous fuel cannot be supplied smoothly. Therefore, there is a problem in that the engine cannot be started by using the gaseous fuel when it is cold.

(Object of the Invention) The present invention has been made in order to solve the above-mentioned problems of the prior art. In a fuel control device for an engine that switches between liquid fuel and gas fuel, cold start is performed. So that you can also select a gaseous fuel,
In addition, it is possible to prevent redundant fuel supply at the time of fuel switching and to prevent a blank period from being supplied to the fuel due to unprepared supply of the gaseous fuel, especially when switching from liquid fuel to gaseous fuel. To aim.

The fuel control device for an engine according to the present invention includes a float chamber for receiving liquid fuel supplied from a fuel pump and a carburetor for supplying liquid fuel having a choke valve in an intake passage, and a pressure vessel. In a fuel supply device for an engine, in which a mixer for supplying gaseous fuel that receives the supply of gaseous fuel from a vaporizer is arranged upstream of a choke valve of the vaporizer, the liquid fuel is allowed to be supplied from the vaporizer. Control valve that can be switched between an open operation position that closes the liquid fuel supply and a closed operation position that stops the supply of the liquid fuel, and a high pressure pipe that connects the pressure vessel and the primary chamber of the vaporizer and opens the high pressure pipe. A cut-off valve capable of switching between an on-operation position and an off-operation position for closing the high-pressure pipe, and a pressure in the primary chamber which is attached to the primary chamber and is equal to or more than a set value. A pressure switch that is turned on at the above time and turned off at a value less than a set value is provided, and the first connection position at which the fuel pump that selects the gaseous fuel is stopped and the cutoff valve is turned on is selected and the liquid fuel is selected. Configuring a first circuit switchable to a second connection position for operating the fuel pump and turning off the cutoff valve, and connecting the pressure switch in series with a drive coil of the control valve. A second circuit for opening the control valve when the pressure switch is turned on and closing the control valve when the pressure switch is turned off; and
And a means for canceling the closing operation of the choke valve when the circuit is in the first connection position.

(Operation) When the first circuit is switched to the first connection position so as to select the gaseous fuel during the use of the liquid fuel, the cutoff valve is actuated to turn on the gaseous fuel from the pressure vessel to the primary chamber of the vaporizer. Is allowed and the operation of the fuel pump is stopped. Then, after the supply of the liquid fuel from the vaporizer continues for a while, when the pressure in the primary chamber of the vaporizer exceeds the set value, the pressure switch of the second circuit is turned off, and the control valve is closed. The supply of the liquid fuel is stopped, and the gaseous fuel flows into the mixer through the primary chamber and the secondary chamber of the vaporizer and is supplied to the intake passage. Also, when the first circuit is switched to the second connection position so as to select the liquid fuel while using the gaseous fuel, the cutoff valve is turned off and the gaseous fuel from the pressure vessel to the primary chamber of the vaporizer is discharged. The supply is stopped, the fuel pump is operated, and the supply of the liquid fuel to the float chamber of the carburetor is started. Then, after the gas fuel is continuously supplied from the mixer for a while, when the pressure in the primary chamber of the vaporizer becomes less than the set value, the pressure switch is turned on to open the control valve and open the liquid from the vaporizer to the intake passage. Fuel is supplied. Further, even at the cold start when the choke valve is normally closed, the choke valve is released from the closed operation and opened when the mixer is selected, so that the gas fuel can be smoothly supplied.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, the fuel control device of this embodiment supplies a vaporizer 1 for supplying liquid fuel (gasoline) and a gaseous fuel (LPG) filled in a pressure vessel 2 via a vaporizer 3. The mixer 4 and the mixer 4 are installed in the intake passage 6 of the internal combustion engine 5.

The carburetor 1 is provided between the air purifier 7 and the intake passage 6, and is supplied to the internal combustion engine 5 and the venturi parts 8a and 8b for sucking and atomizing the liquid fuel by the negative pressure of the internal combustion engine 5. Throttle valves 9a, 9b for controlling the amount of air-fuel mixture to be generated, a main nozzle 10 opened in the venturi portion 8a, and a fuel tank 11
A float chamber 14 for always accumulating a fixed amount of liquid fuel flowing in from the fuel filter 12 and the fuel pump 13;
It is composed of a fuel outflow passage 15 that connects the float chamber 14 and the main nozzle 10. The main nozzle 10 is directly opened / closed by a control valve 16 composed of a solenoid valve.

On the other hand, the mixer 4 is further upstream of the choke valve 17 provided upstream of the venturi portion 8a,
It is connected to the secondary chamber 3a of the vaporizer 3 through a low pressure pipe 18.

The vaporizer 3 includes a primary chamber 3b (high pressure chamber) and a secondary chamber 2b with a valve mechanism including a spring material and a diaphragm as main components.
It is divided into the next chamber 3a (low pressure chamber).

The primary chamber 3b of the vaporizer 3 is connected to the pressure vessel 2 via a high pressure pipe 19 for supplying gaseous fuel, and a cutoff valve 20 for opening and closing the high pressure pipe 19 is provided in the middle of the high pressure pipe 19. The cutoff valve 20 is operated by a changeover switch 23 connected in series with a battery 21 and a starting switch 22. One contact of the changeover switch 23 is connected to the fuel pump 13.

Further, a pressure switch 24 that is turned on when the pressure in the primary chamber 3b becomes less than a set value is attached to the primary chamber 3b of the vaporizer 3, and one contact of the pressure switch 24 has a changeover switch 23. And a start switch 22 and the other contact is connected to the drive coil of the control valve 16.

Therefore, when the internal combustion engine 5 is driven by the liquid fuel supplied through the carburetor 1, when the driver operates the changeover switch 23 to switch to the drive by the gaseous fuel, the operation of the changeover switch 23 causes the fuel to be changed. When the pump 13 is stopped and the cutoff valve 20 is opened, the gaseous fuel in the pressure vessel 2 passes through the high pressure pipe 19 and enters the vaporizer 1 in the vaporizer 3.
It flows into the next chamber 3b.

In this state, the supply of liquid fuel from the main nozzle 10 has not been stopped yet.

When the pressure in the primary chamber 3b rises and exceeds the set value, the pressure switch 24 is turned off, and the circuit from the battery 21 to the pressure switch 24 and the control valve 16 via the start switch 22 is opened. The control valve is closed to close the main nozzle 10 of the carburetor 1 and stop the supply of liquid fuel to the intake passage 6.

Further, almost at the same time when the pressure switch 24 is turned off, the gaseous fuel flows from the primary chamber 3b of the vaporizer 3 into the secondary chamber 3a,
It reaches the mixer 4 through the low pressure pipe 18, and the air purifier 7
It is mixed with the air taken in from and is supplied to the intake passage 6.

In this way, until the supply of gaseous fuel is ready,
When the liquid fuel from the carburetor 1 is supplied and the pressure in the primary chamber 3b rises and the preparation is completed, the main nozzle 10 is closed to prevent the redundant supply of fuel and the blank period of supply from occurring. is doing.

On the other hand, when the liquid fuel is switched to the liquid fuel while it is being used, the cutoff valve 20 is closed by operating the changeover switch 23, and the fuel pump 13 is started. However, the control valve 16 closing the main nozzle 10 of the vaporizer 1 is not immediately opened. When the gaseous fuel in the pressure regulator 3 is consumed and the pressure in the primary chamber 3b of the vaporizer 3 falls below the set value, the pressure switch 24 is turned on and the circuit of the control valve 16 is closed. The control valve 16 is opened and the main nozzle 10 is opened.

As a result, the liquid fuel is supplied from the main nozzle 10 to the intake passage 6.

Also in this case, after the fuel in the gaseous fuel supply system passage from the secondary chamber 3a of the vaporizer 3 to the mixer 4 is discharged,
Since the main nozzle 10 of the carburetor 1 is opened, the dual supply of the two types of fuel hardly occurs.

The connection point on the battery 21 side of the pressure switch 24 is
As shown by the chain double-dashed line in FIG. 1, it may be provided between the changeover switch 23 and the fuel pump 13.

By the way, in the fuel control device of this embodiment, the relay R is provided between the changeover switch 23 and the fuel pump 13, and a switching circuit in which the water temperature switch 25 and the idle switch 26 are arranged in series is provided, so However, when the water temperature is high, the circuit is configured to forcibly select LPG even if the driver is selecting gasoline. At warm start, so-called warm lock occurs and it becomes impossible to start, so in order to prevent it, I choose the LPG with a higher octane number.

Further, the vaporizer 3 is provided with a hot water passage 27 for promoting the vaporization of the liquefied gas by the engine cooling water, but when vaporization is improved more than necessary and the temperature of the fuel gas rises, the output decreases conversely. Therefore, in this embodiment, a flow rate control valve 28 is provided in the outflow passage of the cooling water, and the flow rate of the cooling water is controlled according to the output of the fuel temperature sensor 29.

Further, the fuel control device is provided with choke releasing means 30 which is activated by a signal for opening the cutoff valve 20.

The choke releasing means 30 uses a solenoid type actuator of the auto choke mechanism shown in FIG.

As shown in FIG. 2, the choke valve 17 at the air inlet of the carburetor 1 is rotatably attached to the shaft 31. A choke lever 32 is fixed to this shaft 31.
One end of the bimetal 33 is engaged with the end portion of the 32, and the choke valve 17 is configured to be opened by the bimetal 33 according to the outside air temperature. This bimetal 33 is heated by an electric heating coil or the like, and due to its deformation, the choke valve 17
Rotate clockwise. Further, the choke valve 17 is provided with a fast idle cam 35 via a choke lever 32 and a link 34.
The fast idle cam 35 is connected to the shaft 36.
Is rotatably supported by the carburetor 1 main body.

A throttle valve 9a is rotatably supported by the throttle valve shaft 37 downstream of the choke valve 17 with respect to the carburetor 1. A throttle valve lever 38 is fixed to the throttle valve shaft 37, and the throttle valve lever 38 is a cam step portion of the fast idle cam 35.
One of 35a to 35d, which in this case is engaged with the cam step portion 35a, regulates the opening degree of the throttle valve 9a.

The shaft 36 is provided with a rotatable cam 39,
The end 39a of the cam 39 is engaged with the fast idle cam 35. The cam 39 is connected to an actuator 41 via a link 40.

In this embodiment, a complete explosion compensating device 42 is provided, and when the engine is completely exploded, a negative pressure in a portion downstream of the throttle valve 9a of the intake passage 6 is introduced to open the choke valve 17 at a constant opening. ing.

When the outside air is in a low temperature state, the choke valve 17 is in the fully closed position due to the closing force of the bimetal 33, while the throttle valve 9a has a fast stop because the throttle valve lever 38 is engaged with the cam step portion 35a. It is held at the idle position. When the engine is started in this state, the engine rotates at 2000 rpm or higher and the engine is warmed up within a few minutes. On the other hand, as the warm-up progresses, the bimetal 33 is heated and deformed by the electric heating coil or the like, and the choke lever 32 is rotated clockwise to gradually open the choke valve 17. Also choke lever
As the 32 rotates, the fast idle cam 35 also tries to rotate in the same direction via the link 34. However, since the cam step portion 35a of the fast idle cam 35 is engaged with the throttle valve lever 38, the fast idle cam 35 does not rotate,
The rotation of the choke valve 17 is also restricted. Therefore, the throttle valve 9a is maintained at the fast idle opening degree, and the engine speed gradually increases as the warm-up progresses.

As the temperature of the cooling water in the intake manifold rises to 35 ° C. as the warming-up progresses, the actuator 41 is operated, the cam 39 is rapidly rotated clockwise through the link 40, and the fast idle cam 35 Also rotate in the same direction. The throttle valve lever 38 is disengaged from the cam step portion 35a and is rotated until it engages with the cam step portion 35d, and the throttle valve 9a has a normal idle opening at this position, and the engine speed is also normal. It will be the idle speed. As a result, engine noise can be prevented and fuel consumption can be improved.

At the same time, the choke lever 32 also rotates clockwise, and the choke valve 17 is opened, for example, by about 40 °. Therefore, the intake air amount increases and the negative pressure acting on the carburetor 1 decreases, so that the supplied fuel decreases and the air-fuel ratio of the air-fuel mixture becomes thin. Therefore, the increase of unburned components in the exhaust gas can be suppressed.

Next, if the outside air temperature is relatively high, for example 20 ° C,
Considering the startability of the engine, the choke valve 17 is in the fully closed position, the throttle valve lever 38 is also engaged with the cam step portion 35a, and the throttle valve 9a is held at the fast idle opening degree. When starting in this state, the cam 39 is rapidly rotated clockwise by the actuator 41 after the complete explosion. This cam 39
With the rotation of, the engagement between the cam step portion 35a and the throttle valve lever 38 is released, the throttle valve 9a becomes the normal idle opening degree, the engine speed also becomes the normal idle speed, and the engine noise is reduced. It is possible to prevent and improve fuel efficiency. At the same time,
The choke valve 17 is also opened, and the increase of unburned components in the exhaust gas can be suppressed.

The auto choke mechanism used in this embodiment is basically as described above, and has a circuit configuration in which the solenoid type actuator 41 is operated at the same time when the cutoff valve 20 is opened.

This will cause the choke to close when LPG is selected.

In the above embodiment, the one using the auto choke is described, but even if the manual choke is used, for example, the closing operation of the choke is released by cutting the energization to the holding magnet. can do.

Further, the present invention can be implemented in various other modes.

(Effect of the Invention) Since the present invention is configured as described above, in a hybrid engine equipped with a vaporizer for supplying liquid fuel and a mixer for supplying gaseous fuel, the gaseous fuel is selected when cold, The inconvenience that the choke valve closes and the fuel supply is interrupted does not occur. In addition, it is possible to prevent double supply of fuel at the time of fuel switching, and also to prevent a blank period from being supplied to the fuel due to unprepared supply of the gaseous fuel especially at the time of switching from the liquid fuel to the gaseous fuel. it can.

[Brief description of drawings]

FIG. 1 is a schematic overall view of an embodiment of the present invention, and FIG. 2 is a detailed view of choke releasing means which is a main part of the embodiment. 1: Vaporizer, 3: Vaporizer, 4: Mixer, 16: Control valve, 1
7: Choke valve, 20: Cut-off valve, 23: Changeover switch, 30: Choke releasing means, 41: Actuator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Matsuno 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP 61-272426 (JP, A) JP 61- 283734 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A carburetor for supplying liquid fuel, which has a float chamber for receiving liquid fuel from a fuel pump and a choke valve, is provided in an intake passage, and gas fuel is supplied from a pressure vessel through a vaporizer. In an engine fuel supply device in which a mixer for supplying gaseous fuel is arranged on the upstream side of a choke valve of the vaporizer, an open operating position for allowing the liquid fuel to be supplied from the vaporizer and the supply of the liquid fuel are provided. An on-operation position for opening the high-pressure pipe and an off-operation for closing the high-pressure pipe, which is interposed in a high-pressure pipe connecting the pressure vessel and the primary chamber of the vaporizer, and a control valve switchable to a closed operation position for stopping. A cut-off valve that can be switched to a position, and is turned on when the pressure in the primary chamber is less than a set value, and is turned on when the pressure in the primary chamber is less than the set value. A pressure switch for switching the gas pump to stop the fuel pump and turn on the cut-off valve, and operate the fuel pump to select liquid fuel and the cut-off valve. A first circuit that can be switched to a second connection position that is turned off is configured, the pressure switch is connected in series with a drive coil of the control valve, and the control valve is opened when the pressure switch is turned on. A second circuit for closing the control valve when the pressure switch is turned off, and releasing the closing operation of the choke valve when the first circuit is in the first connection position. A fuel control device for an engine, characterized by comprising means.