JPS6255453A - Fuel controlling device for engine - Google Patents

Abstract

PURPOSE:To start an engine after sufficient fuel has been fed to a carburetor by energyzing a solenoid for a period of time, which is set by a timer in advance, upon receiving of an ignition signal so as to open a fuel cock. CONSTITUTION:When an engine switch is turned on, a monostable multi-vibrator 14 is driven so as to open an electromagnetic cock 9 through a driver 16 for period of time set by a timer, then fuel is fed to a fuel chamber of a carburetor from a fuel tank. And when the engine switch is placed to a start position, the monostable multi-vibrator 14 is operated so as to open the electromagnetic cock 9, and a controlling circuit 13 will not actuate a flip-flop circuit 15 so as to have the electro-magnetic cock 9 held open through the driver 16 before it is detected by an engine rotation detecting circuit 8 that an engine speed has come upto a constant one.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an engine fuel control device for supplying fuel to an engine and controlling the engine.

Concave - Generally speaking, in working engines such as engine generators and lawn mowers, the fuel in the tank is sometimes supplied to the engine's carburetor by dripping, without using a fuel pump. At that time, in order to prevent the fuel in the fuel chamber of the carburetor from overflowing during transportation, etc., a fuel cock is installed in the fuel supply system to cut off the fuel supply, but depending on the structure of the aircraft, Starting the engine.

It may be difficult to open and close the fuel cock when stopping the vehicle. Also, if the fuel cock is left closed for a long time, the fuel in the fuel chamber of the carburetor will evaporate and become empty, so it is necessary to open the fuel cock in advance to supply fuel before starting the engine. It has become.

Therefore, in order to prevent forgetting to operate the fuel cock and to open the fuel cock before starting the engine, a solenoid valve for opening and closing the fuel cock is operated in conjunction with the on/off of the engine ignition switch. However, if such a measure is taken, if the ignition switch is left on, the solenoid will continue to be energized and the fuel cock will remain open, causing the supply of fuel to become stagnant during transportation, etc., as described above. Problems arise such as overflow and battery discharge.

In addition, since the stop operation is performed while the engine is running at a constant speed, the engine may be in an environment where afterburn is likely to occur due to the rotation due to the inertia of the generator etc. after the stop operation. In some cases, the fuel ejected from the venturi nozzle of the carburetor is immediately cut off.

For example, conventionally, when the engine is stopped, the output of the generator, which rotates due to inertia, is applied to a solenoid valve for fuel cut to cut off the ejected fuel. -1441
If the inertial mass is large, taking such measures will prevent afterburn even when the generator output falls below the holding voltage of the solenoid valve and the fuel cut is released before the engine stops. There is a risk of creating an environment where this is likely to occur.

The present invention has been made in consideration of the above points, and provides an engine that can automatically open and close the fuel cock according to the engine condition and optimally open and close the fuel cock during engine stop operation. A fuel control device is provided.

In order to achieve the object, the present invention provides a solenoid means for opening and closing the fuel cock, and energizes the solenoid for a preset time by a first timer in response to an ignition ON signal in the engine to open the fuel cock. When the engine starts and its rotation speed rises to a predetermined level within the timer setting time, the solenoid is held in its energized state by detecting this, and the engine rotation speed rises to a predetermined level within the timer setting time. If no such occurrence is detected, control means is taken to deenergize the solenoid and close the fuel cock based on the time-up of the timer.

At the same time, a fuel cut solenoid valve is installed to cut the fuel ejected from the engine, and in response to the ignition off signal, the solenoid is energized for a preset time by a second timer to cut the fuel until the engine stops. We are trying to take control measures to make this happen.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows an example of the basic circuit configuration of an engine working machine, which includes a starter 2 for starting the engine using a battery 1 as a driving source, an engine ignition bag [3, an electric load 4, and a charging battery 1]. A combination switch 5 is provided which switches connections between terminals in conjunction with an engine switch (not shown). Note that here, as the engine ignition device 3, a transistor type device is used which is self-triggered by the rotation of a pulser P provided with a permanent magnet MG. Further, in the starter 2, when a starting relay coil 21 is energized, its relay contact 22 is closed to drive the starting motor M.

FIG. 3 shows a circuit arrangement in which the connection between terminals is switched by the combination switch 5 is arranged independently, and the connection between the terminals in each circuit component is switched by the combination switch 5 as shown in FIG. It is done like this.

That is, when the engine switch is set to the on position (ignition on), the output terminal C of the generator G
When HG, battery terminal BAT and load terminal LD are connected, and the engine switch is set to the start position, generator G output terminal CHG and battery terminal BAT are connected.
- When the load terminal LD and starter relay coil terminal ST are connected and the engine switch is set to the off position (ignition off), the ignition terminal IG
and the ground terminal 8 are connected.

The present invention resides in such an engine working machine, and includes an electromagnetic cock that can be opened and closed by energizing and deenergizing a solenoid as a fuel cock installed in a fuel supply system that supplies fuel from a fuel tank to an engine. The electromagnetic cock is opened and closed by a fuel control device 6 shown in FIG.

The present invention also provides a fuel cut solenoid valve that closes when the solenoid is energized to prevent fuel from being ejected from the venturi nozzle in the engine's carburetor. This is done by a fuel control device 6 shown in FIG.

The fuel control device 6 outputs a load terminal LD signal that rises to a high level when the engine switch is set to the on position, a starter relay coil terminal ST signal that rises to a high level when the engine switch is set to the start position, and a power generation signal. The output of an engine rotation speed detection circuit 8 that detects that the engine rotation speed has risen to a certain level when the output voltage of the charge coil 7 of the machine G exceeds a preset certain level and generates a high level signal. It consists of a control circuit 13 that gives control commands to the control systems R11 and R12 of the electromagnetic cock 9 and the fuel cartridge solenoid valve 10, respectively, according to a predetermined algorithm in accordance with the combination with the signal N. Its control circuit 1
3, it is composed of a logic circuit formed by a combination of various logic gates or an ECU that performs control according to a preset program.

? T! The control system for the magnetic cock 9 is a monostable multivibrator provided as a timer that opens the electromagnetic cock 9 for a certain period of time when the engine switch is set to the on position and when the engine switch is set to the start position. 14, a flip-flop 15 that holds the electromagnetic cock 9 in an open state when it is detected that the engine speed has risen to a predetermined value, and an OR signal of each output of the monostable multivibrator 14 and the blip prop 15. It is composed of a driver 16 that energizes and deenergizes the electromagnetic cock 9.

In addition, the control system of the fuel cut solenoid valve 1o includes a timer 1 which provides an energizing signal to the driver 17 of the fuel cut solenoid valve 10 for a preset time according to a fuel cut command issued from the control circuit 13.
8 is provided.

The operation of the engine fuel control system according to the present invention configured as described above will be explained below with reference to a time chart of signals of each part shown in FIG.

First, when the engine switch is turned on at tl,
The control circuit 13 operates the monostable multivibrator 14 when the LD signal becomes high level and operates the monostable multivibrator 14, and sets the timer setting time Tl (for example, 2
The electromagnetic cock 9 is opened for only 0 seconds) to supply fuel from the fuel tank to the fuel chamber of the carburetor. At this time, the timer setting time T1 is set to be a time sufficient to supply fuel to the fuel chamber of the carburetor, which has been left empty for a long time.

As the timer time T1 elapses, the monostable multivibrator 14 operates in reverse, thereby closing the electromagnetic cock 9 and cutting off the fuel supply to the carburetor.

Next, when the engine switch is put into the start position at time t2 after the timer setting time, the control circuit 13
Knowing this when the double signal becomes high level, the monostable multivibrator 14 is operated and the electromagnetic clutch 9 is opened in the same manner as described above, after which the engine is started and the engine speed is kept constant (for example, the rated At time t3 (t
2-t3 is shorter than the timer setting time T1), the control circuit 13 operates the flip-flop 15 and uses its Q output to hold the electromagnetic cock 9 in the open state via the driver 16.

Next, when the engine switch is turned off at time t4, the control circuit 13 knows this because the LD signal becomes low level, and gives a fuel cut command to the timer 18, thereby causing the time T2 set by the timer 18 to continue. During this time, the driver 17 is driven to continue energizing the fuel cut solenoid valve 1o to cut off the fuel in the engine. The timer setting time T2 is set so that the fuel cut is canceled after the engine is stopped, taking into account the rotation due to inertia of the generator G etc. after the engine stop operation is performed.

In addition, at time t5 when the engine switch has been turned off at time t4 and the engine speed has decreased to a constant speed, the output signal N of the engine speed detection circuit 8 becomes low level, which causes the control circuit 13 to reverse the flip-flop 15. Then, the electromagnetic cock 9 is closed via the driver 16.

Further, as shown in FIG. 6, when the engine switch is turned on at time tl and then put into the start position at time t2' within the timer setting time T1, the control circuit 13 controls the engine rotational speed. At time t3' when the output signal N of the detection circuit 8 becomes high level, the electromagnetic cock 9 is held open.

As described above, in the engine fuel control device according to the present invention, the fuel cock can be automatically opened and closed without forgetting to operate the cock when starting or stopping the engine. If the engine is started after waiting for the timer setting time T1 after being left unused for a long time, the engine can be started with sufficient fuel supplied to the carburetor, and the engine When running and stopping repeatedly in relatively short cycles, the timer setting time T
The engine can now be started immediately without waiting for I. Furthermore, even if the engine switch is left on, the fuel cock will automatically close after a certain period of time, so the fuel supplied to the carburetor may overflow during transport, or the fuel cock solenoid may continue to be energized. This effectively prevents the battery from discharging.

Furthermore, when the engine is stopped, the timer continues to energize the fuel cut solenoid valve until the engine is stopped, making it possible to prevent engine afterburn.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram showing an embodiment of an engine fuel control device according to the present invention, Fig. 2 is a diagram showing an example of the basic circuit configuration of an engine working machine, and Fig. 3 shows each circuit component. Figure 4 is a diagram showing the connection switching status of each circuit component by a combination switch.
FIGS. 5 and 6 are diagrams each showing an example of a time chart of each part signal in the same embodiment. 7... Charge coil of generator G 8... Engine speed detection circuit 9... Electromagnetic cock 10... Solenoid valve for fuel cut 13... Control circuit
14... Monostable multivibrator 15... Flip-flop 16.17... Driver 18...
Timer Fig. 2, -111---------/--Fig. 3

Claims (1)

[Claims] 1. Solenoid means for opening and closing the fuel cock provided in the fuel supply system supplied from the fuel tank to the engine, and a solenoid means for opening and closing the fuel cock for a preset time by a timer in response to an ignition-on signal in the engine. An engine fuel comprising means for energizing the fuel cock to open the fuel cock, and means for detecting that the engine speed has risen to a predetermined value within the timer setting time and maintaining the energized state of the solenoid. Control device. 2. Solenoid means for opening and closing the fuel cock provided in the fuel supply system supplied from the fuel tank to the engine, and energizing the solenoid for a preset time by a first timer in response to an ignition on signal in the engine. means for causing the solenoid to maintain an energized state by detecting that the engine speed has risen to a predetermined value within the timer setting time; and a fuel for cutting the fuel ejected from the engine. An engine fuel control device comprising a solenoid valve means for cutting, and means for operating the solenoid valve for a preset time by a second timer in response to an ignition off signal to cut the fuel.