JPH02211366A - Switching-feeding device for two-kinds of fuel for engine - Google Patents

Abstract

PURPOSE:To automatically carry out switching of fuel free from the exhaustion of fuel by opening a gasoline cut-off valve and closing and LPG cut-off valve when an engine is started and opening the LPG cut-off valve when the engine reaches a prescribed temperature and closing the gasoline cut-off valve after the lapse of a set time. CONSTITUTION:When an engine 23 is started, an LPG cut-off valve 17 is closed by the signal of an electronic controller 34, and gasoline cut-off valves 9 and 10 are opened, and only gasoline is supplied into a suction passage 22. When it is confirmed by a temperature sensor 32 that the engine 23 reaches a prescribed temperature, the LPG cut-off valve 17 is opened, and after the lapse of a prescribed time, the electronic controller 34 transmits a signal for closing the gasoline cut-off valves 9 and 10. Therefore, the operation from the start of the engine 23 to warming at a constant temperature is carried out by using gasoline, and replacement of gasoline in a gasoline carburetor 1 is carried out sufficiently by feeding gasoline for a set time, and switching to LPG can be carried out at a proper time automatically without generating the exhaustion of fuel.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a device that automatically switches between two types of fuel and supplies it to an engine, and is mainly used in the fuel supply system of an automobile engine. .

(Prior art) Fuel supply systems that can switch between two types of fuel as appropriate, such as using gasoline for starting and warming up the engine and using inexpensive LPG for normal operation, are known. It is. This fuel supply system includes a gasoline system that includes a gasoline carburetor that supplies gasoline during startup and warm-up to improve startability in cold weather, and a gasoline system that supplies LPG to the same intake path as the gasoline carburetor during normal operation. LP including vaporizer to supply
Switching between the gasoline system and the LPG system is achieved by opening and closing electromagnetically driven on-off valves installed in the fuel passages of each system using a manual changeover switch, and simultaneously closing the fuel passages of unnecessary systems. This is done by opening the fuel passage of the system in use (see Utility Model Publications No. 61-24682, No. 62-42105, and No. 62-46844).

However, since the fuel is changed by the driver's manual operation of a changeover switch, it requires skill to switch from gasoline to LPG at an appropriate point after starting, taking fuel economy into account. This tends to cause problems such as switching over in a short period of time, causing the engine to malfunction, or using gasoline even after warming up, resulting in uneconomical results.

Also, if you forget to switch and use only gasoline, or if you use LPG and then forget to switch at the next start, it is possible to use only gasoline.
There is a risk that one fuel will be completely consumed and the engine will stop midway through operation due to repeated starting and subsequent operation.

Furthermore, when switching from gasoline to LPG, if the gasoline on-off valve is installed on the inlet side of the gasoline vaporizer as disclosed in the above-mentioned Japanese Utility Model Publication No. 62-46844, All of the gasoline is sucked out into the intake passage and combined with LPG, making the mixture rich.

On the contrary, the above-mentioned Utility Model Publication Nos. 61-24682 and 62-421
As disclosed in each publication No. 05, if the gasoline on-off valve is installed on the constant oil level chamber outlet side of the gasoline vaporizer, it will take some time for LPG to start being sucked out into the intake passage. This has the disadvantage of running out of fuel and causing the engine to stop.

Furthermore, it is desirable to switch from gasoline to LPG when the engine has warmed up to a certain temperature from both fuel economy and emission countermeasures, but the driver should switch at the appropriate time. Otherwise, if you estimate the warm-up state and switch immediately after starting in the summer, the gasoline in the gasoline vaporizer will hardly be replaced, resulting in deterioration and gummy components adhering to the internal mechanism. There is also a concern that malfunction may occur.

(Problems to be Solved by the Invention) The present invention provides a dual-beam fuel supply system that can selectively use two types of fuel, with a gasoline system on-off valve installed on the outlet side of the constant oil level chamber of the gasoline vaporizer. When the engine is warmed up, it is difficult to change the fuel properly, it is easy to forget to change the fuel, and the fuel runs out when the change is made. To solve the above-mentioned problem of not being able to switch between fuels at the correct timing, and to switch fuels automatically and at appropriate times without running out of fuel, and furthermore, without causing deterioration or deterioration of the gasoline inside the gasoline carburetor. is intended to provide.

(Means for solving the problem) An engine is provided with a gasoline system that supplies gasoline from a gasoline tank to an intake passage through a gasoline vaporizer, and an LPG system that supplies LPG from an LPG cylinder to an intake passage through a vaporizer. The measures taken by the present invention to solve the above-mentioned problems of the fuel supply system are as follows.

That is, one is a gasoline cutoff valve provided in the fuel passage from the constant oil level chamber of the gasoline vaporizer to the intake passage, and the other is a gasoline cutoff valve provided in the fuel passage leading from the constant oil level chamber of the gasoline
The electronic control device includes an LPG cutoff valve provided in the LPG supply path from the PG cylinder to the vaporizer, an electronic control HR to which the engine status is input, and a temperature sensor to detect the engine temperature; When starting the engine, the gasoline cutoff valve is opened and the LPG cutoff valve is closed to supply gasoline to the intake passage, and when it is confirmed by the temperature sensor that the engine has reached a predetermined temperature, the LP
The G cutoff valve is opened, and when a preset time has elapsed, the gasoline cutoff valve is closed, and LPG is then supplied to the intake passage.

The other is a gasoline cutoff valve provided in the fuel passage from the constant oil level chamber of the gasoline vaporizer to the intake path, and an LPG cutoff valve provided in the LPG supply path from the LPG cylinder to the vaporizer. The engine includes an electronic control device into which the engine status is input, a timer for time setting, and a temperature sensor that detects engine temperature; the electronic control device opens the gasoline cutoff valve when the engine is started, and The LPG cutoff valve is closed to supply gasoline to the intake passage, and when the set time of the timer has elapsed and the temperature sensor confirms that the engine has reached a predetermined temperature, the LPGfi cutoff valve is opened. Further, when a preset time has elapsed, the gasoline cutoff valve is closed, and LPG is then supplied to the intake passage.

Note that with the means for opening and closing the gasoline system on the inlet side of the gasoline vaporizer, the gasoline in the gasoline vaporizer is completely consumed before switching to LPG, which delays the supply of gasoline at the next start. If the constant oil level chamber is a float type, there are disadvantages such as the need for a means to fix the float, which is troublesome. Therefore, in the present invention, the gasoline system is opened and closed on the outlet side of the constant oil level chamber. It was adopted.

(Function) When the engine starts, the LPG system is closed and the gasoline system is opened according to a signal from the electronic control device, and only gasoline is supplied to the intake passage. In addition, an electronic signal is sent to open the LPG system when the engine reaches a predetermined temperature, or when the timer setting time has elapsed and the engine reaches a predetermined temperature, and then to close the gasoline system when a predetermined time has elapsed. Emitted from the control device. As a result, gasoline is used to start the engine and warm it up to a constant temperature, and by using a means to supply gasoline for a set period of time, the gasoline in the gasoline vaporizer is sufficiently replaced and the switch to LPG is performed. This can be done automatically and without running out of fuel.

(Example) The present invention will be described in detail with reference to the drawings.

In the first time, the LPG mixer 11 and the air cleaner 20 were stacked and fixed in order on the gasoline vaporizer 1 placed vertically, and one intake passage 21 formed by the gasoline vaporizer 1 and the LPG mixer 11 was fixed. is connected to an engine 23 via an intake manifold 22.

The gasoline carburetor 1 includes a float-type constant oil level chamber 2, a main fuel passage 3 that supplies the gasoline to an intake passage 21, and a low-speed fuel passage 4.
It is a well-known configuration with a gasoline tank 5
An electromagnetically driven passage opening/closing valve 8 is provided in the gasoline supply passage 7 which is connected to the constant oil level chamber 2 via the fuel pump 6, and an electromagnetically driven passage opening/closing valve 8 is provided in each of the main fuel passage 3 and the low speed fuel passage 4. A shutoff valve 9.10 is provided.

The LPG mixer 11 connects the venturi 12 and LPG to the intake path 2.
1, and a secondary chamber 1 of the LPG cylinder 14 and the vaporizer 15.
Electromagnetically driven LPG is connected to the LPG supply path 16 connected to 5a.
A shutoff valve 17 is provided, and the vaporizer 1
The secondary chamber 15b of No. 5 and the nozzle 13 are connected by an LPG passage 18.

The secondary chamber side 15b of the vaporizer 15 is provided with a locking mechanism as shown in the above-mentioned Japanese Utility Model Publication No. 62-46844, and when LPG is used, the locking mechanism is activated by introducing the engine's suction negative pressure. An electromagnetically driven negative pressure opening/closing valve 25 is provided in the negative pressure introduction path 24 which is released but operates a locking mechanism when not in use to supply or not supply LPG. In addition, when LPG is not used, air is introduced into the secondary chamber 15b to eliminate the inconvenience of venturi negative pressure acting on the secondary chamber 15b through the LPG passage 18 and forcing the secondary valve lever to operate. Route 26 is air cleaner 2
0 and the secondary chamber 15b, and an electromagnetically driven air opening/closing valve 27 is provided in this air introduction path 26.

Further, a rotational speed sensor 31, a temperature sensor 32, and a pressure sensor 33 for the LPG supply path 16 are provided for the engine 23, and electrical signals from these sensors 31, 32, 33, the position of the key switch of the engine 23, and the starter The status etc. are input to the electronic control device 34, and a relay 36 with a built-in timer 35 controls the gasoline system fuel pump 6, the passage opening/closing valve 8, the gasoline cutoff valve 9, 10, and the LPG system LPG cutoff valve 17, Negative pressure on/off valve 25, air on/off valve 27
A predetermined drive signal is sent to each of them.

In this embodiment configured as described above, when the key switch is turned on to operate the engine 23, the key switch signal 37 and the starter signal 38 are manually inputted to the electronic control device 34, and when it is confirmed that the engine 23 is to be started, the relay 36 is activated. At the same time, a drive signal is issued to the gasoline system to operate the fuel pump 6 and keep the passage on-off valve 8 and the gasoline cut-off valve 9.10 in the open position, and also to move the LPG cut-off valve 17 and the negative pressure on-off valve 25 to the closed position. At the same time, a drive signal is issued to the LPG system to hold the air on-off valve 27 in the open position. As a result, gasoline is supplied to the intake passage 22 at the same time as starting.
LPG is not supplied.

Further, when the electronic control device 34 confirms that the temperature of the cooling water of the engine 23 has reached a predetermined temperature, for example, approximately 15° C., based on an electric signal from the temperature sensor 32, or when the predetermined temperature is reached and the engine is started, the operation starts. When a predetermined time preset in the timer 35 of the relay 36 has elapsed,
From relay 36 to LPG cutoff valve 17 and negative pressure on/off valve 25
A drive signal is issued to the LPG system to maintain the air on-off valve 27 in the open position and to maintain the air on-off valve 27 in the closed position. As a result, the secondary chamber 15b of the vaporizer 15 becomes negative pressure, the locking mechanism is released, and the LP of the LPG cylinder 14 is released.
G is fed into the vaporizer 15, gasified under reduced pressure, and can be supplied to the intake passage 22.

Here, when the drive signal is issued to the LPG system, and when a preset time has elapsed, the relay 3
6, a drive signal is issued to the gasoline system to stop the fuel pump 6 and to hold the passage opening/closing valve 8 and the gasoline cutoff valves 9 and 10 in the closed position. By appropriately setting the timing of issuing this drive signal, the gasoline cutoff valves 9 and 10 in the main fuel passage 3 and low-speed fuel passage 4 are closed, and the remaining gasoline on the downstream side is supplied to the intake passage 22. As soon as the LPG is finished, it reaches the nozzle 13 and enters the intake passage 2.
Therefore, both fuels can be supplied at the same time to prevent the mixture from becoming too rich or from running out of fuel, resulting in deterioration of the exhaust composition and malfunction or stoppage of the engine 23.

Note that there is no problem even if the passage opening/closing valve 8 in the illustrated embodiment is omitted. Moreover, when the gasoline cutoff valve 9.10 is installed closer to the constant oil level chamber 2 than any branch point of the low-speed fuel passage 4 of the main fuel passage 3, one piece is sufficient. In addition, vaporizer 15
Negative pressure introduction path 24 and air introduction path 26 that protect the internal mechanism of
Even if it is omitted, the purpose of the present invention is not hindered. Further, the pressure sensor 33 allows a program to be created to detect the consumption of LPG and issue a command to switch to gasoline, but there is no problem in implementing the present invention even if the pressure sensor 33 is omitted.

(Effects of the Invention) According to the present invention, the engine is started and warmed up using gasoline without manual operation by the driver, and the engine is automatically switched to LPG when the engine is warmed up to a predetermined temperature. Fuel economy can be measured. In addition, in order to close the gasoline system after the time elapsed after opening the LPG system,
Gasoline is supplied until LPG begins to be supplied, and fuel is supplied without interruption to prevent engine malfunction or deterioration of exhaust composition.

Furthermore, when switching is performed by taking into account the warm-up state and the gasoline supply time, a considerable amount of gasoline in the gasoline carburetor is replaced, and troubles due to deterioration can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram of FIG. 1. 1... Gasoline carburetor, 2... Constant oil level chamber, 5...
Gasoline tank, 9.10...Gasoline cutoff valve, 11
...LPG m set, 14...LPG cylinder, 1
5... Vaporizer, 17... LPG cutoff valve, 21
...Intake path, 23...Engine, 32...Temperature sensor, 34...Electronic control unit 1 Fig. 34...Timer,

Claims (2)

[Claims] (1) In an engine fuel supply system comprising a gasoline system that supplies gasoline from a gasoline tank to an intake passage via a gasoline vaporizer, and an LPG system that supplies LPG from an LPG cylinder to an intake passage via a vaporizer; A gasoline cutoff valve provided in a fuel passage from a constant oil level chamber of a gasoline vaporizer to an intake passage, and an LPG supply passage provided in an LPG supply passage from the LPG cylinder to a vaporizer.
It is equipped with a cutoff valve, an electronic control device into which engine conditions are input, and a temperature sensor that detects engine temperature; the electronic control device opens the gasoline cutoff valve when the engine is started, and also opens the LPG cutoff valve. When the shutoff valve is closed and gasoline is supplied to the intake passage, and the temperature sensor confirms that the engine has reached a predetermined temperature, the
The PG cutoff valve is opened, and when a preset time has elapsed, the gasoline cutoff valve is closed, and LPG is then supplied to the intake passage. Separate fuel switching supply device. (2) In an engine fuel supply system comprising a gasoline system that supplies gasoline from a gasoline tank to an intake passage via a gasoline vaporizer, and an LPG system that supplies LPG from an LPG cylinder to an intake passage via a vaporizer; A gasoline cutoff valve provided in a fuel passage from a constant oil level chamber of a gasoline vaporizer to an intake passage, and an LPG supply passage provided in an LPG supply passage from the LPG cylinder to a vaporizer.
The engine includes a cutoff valve, an electronic control device into which engine conditions are input, a timer for time setting, and a temperature sensor that detects engine temperature; the electronic control device controls the gasoline cutoff valve when the engine is started. When the valve is opened and the LPG cutoff valve is closed to supply gasoline to the intake passage, the LPG is cut off when the set time of the timer has elapsed and the temperature sensor confirms that the engine has reached a predetermined temperature. The dual fuel is configured to open the valve, and then close the gasoline cutoff valve when a preset time has elapsed, and thereafter supply LPG to the intake passage. Switching supply device.