JPH02211367A - Switching-feeding device for two-kinds of fuel for engine - Google Patents

Abstract

PURPOSE:To permit the economical use of fuel by installing a control system which supplies LPG from start when the engine temperature is diver a set temperature on start or if the time from the engine stop to start is within a set time. CONSTITUTION:When an engine 23 is started, an LPG cut-off valve 17 is closed by the driving signal of an electronic controller 34, and gasoline cut-off valves 9 and 10 are opened, and starting and warming are carried out for a time set by a timer 35 by using gasoline, and then switching to LPG is carried out by opening the LPG cut-off valve 17 and closing the gasoline cut-off valves 9 and 10. When starting is carried out within a previously set time from the stop of the engine or the engine temperature on start is over a previously set temperature, the LPG cut-off valve is opened by the drive signal of the electronic controller 34, and the gasoline cut-off valves 9 and 10 are closed, and LPG is supplied from start, and the fuel economy is improved.

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 done by opening and closing electromagnetically driven shutoff 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 switch, for example, from gasoline to L at an appropriate point after starting, taking fuel economy into consideration.
Switching to PG requires skill and tends to cause problems such as switching over a short time after starting, causing the engine to malfunction, or using gasoline even after warm-up is complete, resulting in uneconomical results.

By the way, as mentioned above, gasoline is used when starting the engine in consideration of startability, but when the engine is stopped and restarted in a short period of time, the engine is sufficiently warmed up. Alternatively, during high temperatures in the summer, the engine is warmed by the atmosphere and is always in a warm-up state, and under these conditions, LPG can be used to start the engine satisfactorily without using gasoline. Furthermore, uniformly using gasoline at startup is not only disadvantageous in terms of fuel economy, but also
If the gasoline system is hot, there is a risk that percolation or sviewing will cause gasoline to be sent into the intake tract when the engine is opened, causing problems such as inability to start or engine stoppage. Unable to perform fuel selection.

(Problems to be Solved by the Invention) The present invention solves the problem that in a two-system fuel supply system in which two types of fuel can be selectively switched, it is difficult to switch the fuel appropriately and it is easy to forget to switch the fuel. In particular, a device that solves the above-mentioned problem of not being able to select an appropriate fuel in response to engine temperature, can automatically and appropriately switch fuels, and can use fuel economically. 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, a gasoline cutoff valve that opens and closes the gasoline system, an LPG cutoff valve that opens and closes the LPG system, an electronic control device into which the engine status is input, a timer for time setting, and a temperature sensor that detects the engine temperature. and at least one of the following.

The electronic control device supplies Ganrin for a certain period of time when the engine starts, and then supplies LPG after that, but when the time from engine stop to engine start is within a preset time, or when the engine humidity at the time of engine start is A control system is set to open and close the gasoline cutoff valve and the LPG cutoff valve so that LPG is supplied from the start when the temperature is higher than a preset temperature.

(Function) When the engine starts, the LPG system is closed and the gasoline system is opened according to the drive signal from the electronic control device.
The engine is started and warmed up using gasoline for the time set by a timer, after which the LPG system is opened and the gasoline system is closed to switch to LPG.

When starting is performed within a preset time from the previous engine stop, or when the engine temperature at the time of starting is higher than the preset temperature, the LPG system is opened and the gasoline system is opened by a drive signal from the electronic control device. Closed,
Fuel economy is measured by supplying LPG from the start.

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

In FIG. 1, an LPG mixer 11 and an air cleaner 20 are stacked and fixed in order on a gasoline vaporizer 1 placed vertically, and one intake passage 21 is formed by the gasoline vaporizer 1 and the LPG mixer 11. 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 nozzle 13 that supplies the LPG cylinder 14 and the primary chamber 1 of 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 IPG 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.

Furthermore, 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, and 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 from the relay 36 with a built-in timer 35, the gasoline system fuel pump 6, the passage opening/closing valve 8, the gasoline cutoff valve 9.101, and the PG 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 input to the electronic control device 34, and when it is confirmed that the engine 23 is to be started, the relay is activated. 36, a drive signal is issued to the gasoline system to operate the fuel pump 6 and keep the passage on-off valve 8 and gasoline cutoff valve 9.10 in the open position, and also closes the LPG cut-off valve 17 and negative pressure on-off valve 25. 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.

Also, the timer 35 of the relay 36 starts operating at the same time as the start, and when a preset time period has elapsed, the relay 36 holds the LPG cutoff valve 17 and the negative pressure on/off valve 25 in the open position, and opens/closes the air. A drive signal is issued to the LPG system to maintain the valve 27 in the closed position. As a result, the pressure in the secondary chamber 15b of the vaporizer 15 becomes negative and the locking mechanism is released, and the LPG in the LPG cylinder 14 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.

The above is the operation when the engine 23 is started in a cold state, but when only a short time has passed since the engine 23 stopped or when the temperature is high in summer, the engine 23 is in a warm-up state. Doesn't require gasoline.

In the illustrated embodiment, when the time from engine stop to next start is within a predetermined time set in advance in the timer 35,
The electronic control device 34 confirms that the predetermined temperature, for example, the cooling water temperature of the engine 23, is approximately 25° C. or higher based on an electrical signal from the temperature sensor 32, and that the key switch signal 37 and starter signal 38 indicate that the engine is started. When the relay 36 stops the fuel pump 6, a drive signal is issued to the gasoline system to keep the passage opening/closing valve 8 and the gasoline cutoff valve 9.10 in the closed position.
A drive signal is issued to the LPG system to hold the PG cutoff valve 17 and the negative pressure on/off valve 25 in the open position, and to keep the air on/off valve 27° in the closed position. As a result, LPG is supplied to the intake passage 22 at the same time as the engine starts, and gasoline is not supplied.

Furthermore, when the temperature sensor 32 is used, if the engine 23 is started in a cold state and warmed up to a predetermined temperature before the time set by the timer 35 has elapsed, control is performed so that a command to switch from gasoline to LPG is issued at that point. Although it is possible to create a system, it is sufficient to use either the timer 35 or the timer 35 in implementing the present invention.

Furthermore, there is no problem even if the passage opening/closing valve 8 is omitted, and only one gasoline cutoff valve 9 or 10 is installed if it is installed closer to the constant oil level chamber 2 than the branch point with the low-speed fuel passage 4 of the main fuel passage 3. That's enough. Moreover, even if the negative pressure introduction path 24 and the air introduction path 26 that protect the internal mechanism of the vaporizer 15 are omitted, the object of the present invention will not be hindered. Further, the pressure sensor 33 makes it possible to create a control system that detects the end of LPG consumption and instructs switching to gasoline, but it goes without saying that it may be omitted.

(Effects of the Invention) According to the present invention, the engine can be automatically started and warmed up using gasoline without manual operation by the driver, and the engine can be switched to LPG after a predetermined period of time has passed. It is possible to measure reliability and appropriate timing of fuel switching. In particular, when it is confirmed that the engine is warmed up based on either the time between stopping the engine and the engine temperature at the time of starting, it is possible to start the engine with LPG instead of gasoline, making it economical to use fuel. It can be used.

[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 mixer, 14...LPG cylinder, 15.
...Vaporizer, 17...LPG cutoff valve, 21...
-Intake path, 23...Engine, 32...Temperature sensor, 34...Electronic control device, 35...Timer,

Claims (1)

[Scope of Claims] An engine fuel supply system comprising 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. In; a gasoline cutoff valve that opens and closes the gasoline system, and the LP
The electronic control device includes an LPG cutoff valve that opens and closes the G system, an electronic control device into which the engine status is input, and at least one of a timer for time setting and a temperature sensor that detects the engine temperature; When the engine starts, it supplies gasoline for a certain period of time, and thereafter supplies LPG, but when the time from engine stop to start is within a preset time, or when the engine temperature at the time of start is higher than a preset temperature. A control system is set to open and close the gasoline cutoff valve and the LPG cutoff valve so that LPG is supplied from the start when the fuel is switched.