JPH06619Y2 - Engine fuel controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel control device for an engine, which controls supply and cut of fuel to the engine.

2. Description of the Related Art Generally, in a working engine such as an engine generator or a lawn mower, fuel in a tank may be supplied to a carburetor of an engine by a drip without using a fuel pump. At that time, a fuel cock is provided in the fuel supply system to cut off the fuel supply so that the fuel in the fuel chamber of the carburetor does not overflow during transportation.However, depending on the structure of the aircraft, Opening and closing the fuel cock may be troublesome when starting and stopping the engine. 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 and supply the fuel before starting the engine. Has become.

In order to prevent forgetting to operate the fuel cock and to open the fuel cock before starting the engine, operate the solenoid valve for opening and closing the fuel cock in conjunction with turning on and off the engine ignition switch. If you take such a measure, if you leave the ignition switch turned on, the solenoid will continue to be energized and the fuel cock will remain open. There are problems such as overflow and discharge of the battery.

In addition, since the stop operation is performed when the engine is operating at a constant speed, the engine after-stop operation may be performed because the environment may cause afterburn of the engine due to the rotation of the generator after the stop operation due to inertia. Immediately after that, the fuel ejected from the venturi nozzle of the carburetor is cut off.

For example, conventionally, when an engine stop operation is performed, the output of a generator that rotates due to inertia after that is given to a fuel cut solenoid valve to cut the jetted fuel (Practical application Sho 60-). 1441
If the inertial mass is large by taking such a measure, the afterburn is still caused when the output of the generator falls below the holding voltage of the solenoid valve and the fuel cut is released before the engine stops. There is a risk that the environment will be prone to occur.

Purpose The present invention has been made in consideration of the above points, and engine fuel control is designed so that automatic opening and closing of the fuel cock and fuel cut at the time of engine stop operation can be optimally performed according to the state of the engine. A device is provided.

In order to achieve the object, the present invention provides an electromagnetic cock as a fuel cock, opens the electromagnetic cock for a preset time by a timer according to an ignition on signal in the engine, and opens the electromagnetic cock according to an ignition start signal in the engine. The electromagnetic cock is opened by the timer, and when the engine starts and its rotation speed rises to a predetermined level, it is detected and the open state of the electromagnetic cock is held, and the engine rotation speed rises to a predetermined level within the timer setting time. When this is not detected, the solenoid is deenergized by the time-out of the timer and the control means for closing the fuel cock is adopted.

At the same time, a fuel cut solenoid valve that cuts the fuel injected from the engine is provided, and the solenoid valve is energized in response to the ignition off signal to start fuel cut, and the engine speed does not cause afterburn. The control means is provided to detect that the fuel pressure has dropped to 0 and deactivate the solenoid valve to release the fuel cut.

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

FIG. 2 shows an example of a basic circuit configuration of an engine working machine, which includes a starter 2 for starting an engine using a battery 1 as a drive source, an engine ignition device 3, an electric load 4, and a battery 1 for charging. A generator G and a combination switch 5 that interlocks with an engine switch (not shown) to switch the connection between the terminals are provided. Here, as the engine ignition device 3, a transistor type device that is self-triggered by the rotation of the pulsar P provided with the permanent magnet MG is used. Further, as the starter 2, when the starting relay coil 21 is energized, the relay contact 22 is closed to drive the starting motor M.

FIG. 3 shows an arrangement of the respective circuit components in which the connection switching between the terminals is performed by the combination switch 5, and the connection switching between the terminals in each of the circuit components is shown in FIG. 4 by the combination switch 5. Is done as follows.

That is, when the engine switch is set to the on position (ignition on), the output terminal C of the generator G is
HG-battery terminal BAT-load terminal LD are connected, and when the engine switch is set to the start position, the output terminal CHG-battery terminal BAT of the generator G
-When the load terminal LD and the 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 E are connected.

The present invention, in such an engine working machine, is provided with an electromagnetic cock that can be opened and closed by energizing and deenergizing a solenoid as a fuel cock provided in a fuel supply system supplied from a fuel tank to an engine, The fuel cock 6 shown in FIG. 1 is used to open and close the electromagnetic cock.

The present invention also provides a fuel cut solenoid valve for preventing the fuel from being ejected from the venturi nozzle in the carburetor of the engine by closing the valve when the solenoid is energized. The fuel control device 6 shown in the figure is used.

The fuel control device 6 includes a load terminal LD signal which rises to a high level when the engine switch is set to the ON position, a starter relay coil terminal ST signal which rises to a high level when the engine switch is set to the start position, and a power generation. The output signal of the engine speed detection circuit 8 which detects that the engine speed has risen to a predetermined level when the output voltage of the charge coil 7 of the machine G exceeds a preset constant level and generates a high level signal. It comprises a control circuit 13 which gives a control command to the control system 11 of the electromagnetic cock 9 and the driver 17 of the fuel cut solenoid valve 10 with a predetermined algorithm in accordance with the combination with N. The control circuit 13 is composed of a logic circuit formed by a combination of logic gates or an ECU that performs control according to a preset program.

The control system 11 of the electromagnetic cock 9 is a monostable multi-valve 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. The vibrator 14, the flip-flop 15 that holds the electromagnetic cock 9 in the open state when it is detected that the engine speed has risen to a predetermined level, and the OR signal of each output of the monostable multivibrator 14 and the flip-flop 15 Therefore, the electromagnetic cock 9 is constituted by the driver 16 for energizing and deactivating the electromagnetic cock 9.

The operation of the fuel control system for an engine according to the present invention constructed as described above will be described below with reference to a time chart of signals of various parts shown in FIG.

First, when the engine switch is turned on at time t1,
The control circuit 13 recognizes that the LD signal becomes high level and operates the monostable multivibrator 14 to open the electromagnetic cock 9 for a timer setting time T1 (for example, 20 seconds) via the driver 16 to open the fuel tank. To supply fuel to the fuel chamber of the carburetor. At this time, the timer setting time T1 is set to be a time sufficient to sufficiently supply the fuel to the fuel chamber of the carburetor that has been left empty for a long time.

The monostable multivibrator 14 reverses as the timer time T1 elapses, thereby closing the electromagnetic cock 9 and cutting off the fuel supply to the carburetor.

Next, when the engine switch is turned to the start position at time t2 after the timer setting time, the control circuit 13 causes ST
When the signal becomes high level, it is known that the monostable multivibrator 14 is operated to open the electromagnetic cock 9 in the same manner as described above, and then the engine is started and the engine speed rises to a predetermined level. At time t3 when the output signal N detected by the engine speed detection circuit 8 becomes high level (t2 is shorter than the timer setting time T1), the control circuit 13 operates the flip-flop 15 to The Q output holds 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 that the LD signal becomes low level and gives a fuel cut command to the driver 17, thereby energizing the fuel cut solenoid valve 10. Then start the fuel cut of the engine.

The output signal N of the engine speed detection circuit 8 becomes low level at time t5 when the engine switch is turned off and the engine speed drops to a certain speed at time t4, which causes the control circuit 13 to invert the flip-flop 15. The electromagnetic cock 9 is closed via the driver 16 and the fuel cut solenoid valve 10 is deenergized via the driver 17 to release the fuel cut of the engine. The engine speed at the time of deenergizing the fuel cut solenoid valve 10 is set to, for example, about 10% of the rating at which engine afterburn does not occur. In this embodiment, the engine speed at the time of deenergizing the fuel cut solenoid valve 10 and the engine speed at the time of holding the electromagnetic cock 9 in the open state and closing it are set to be the same. However, it goes without saying that they may be set with different rotational speeds.

Further, as shown in FIG. 6, when the engine switch is turned on at time t1 and then the engine switch is turned to the start position at time t2 ′ within the timer setting time T1, the control circuit 13 causes the engine speed to be increased. The electromagnetic cock 9 is held open at the time t3 'when the output signal N of the detection circuit 8 becomes high level.

Effects As described above, in the engine fuel control device according to the present invention, when starting and stopping the engine, the fuel cock can be automatically opened and closed without forgetting to operate the cock. If the engine is started after waiting for the timer set time T1 after being left for a while, it becomes possible to start the engine while the carburetor is sufficiently supplied with fuel. When the operation and stop are repeated in a relatively short cycle, the engine can be started immediately without waiting for the timer setting time T1. Even if the engine switch is left on, the fuel cock automatically closes after the timer setting time T1, so the fuel supply in the carburetor overflows during transportation, and the fuel cock solenoid is energized. It is effectively prevented that the battery is continuously discharged.

In addition, when stopping the engine, the engine is stopped because the fuel cut is started after the engine fuel cut is started and it is detected that the engine speed has dropped without causing afterburn. It is possible to prevent the afterburn of the engine regardless of the state change. Further, since the fuel cut solenoid valve is energized only when the generator G is rotating due to inertia when the engine is stopped, it is possible to minimize the discharge of the battery. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an engine fuel control device according to the present invention, FIG. 2 is a diagram showing a basic circuit configuration example of an engine working machine, and FIG. 3 is a diagram showing the respective circuit components. FIG. 4 is an independent diagram, and FIG. 4 is a connection table diagram showing the connection switching state of each circuit component by the combination switch.
FIG. 5 and FIG. 6 are diagrams respectively showing an example of a time chart of signals of respective parts in the embodiment. 7 ... Charge coil of generator G, 8 ... Engine speed detection circuit, 9 ... Electromagnetic cock, 10 ... Fuel cut solenoid valve, 13 ... Control circuit, 14 ... Monostable multivibrator, 15 ... Flip-flop, 16, 17 …driver

Claims (1)

[Scope of utility model registration request] 1. An electromagnetic cock (9) provided in a fuel supply system for supplying fuel from a fuel tank to the engine for supplying and shutting off fuel, and a fuel cut solenoid valve (10) for cutting off fuel injected from the engine. An engine speed detection circuit (8) for detecting the engine speed, and a timer operation is started in response to an ignition on signal in the engine to open the electromagnetic cock (9) for a preset time, A timer operation is started in response to an ignition start signal in the engine, the electromagnetic cock (9) is opened for a preset time, and the engine speed detection circuit (8) raises the engine speed to a predetermined value. When the engine is detected, the open state of the electromagnetic cock (9) is maintained, and the ignition of the engine is turned on. The solenoid valve (10) is urged to perform a fuel cut in response to a signal, and the solenoid valve is detected until the engine speed detection circuit (8) detects that the engine speed is below a predetermined value. Control circuit (1) for maintaining the energized state of (10)
3) A fuel control device for an engine constituted by