JP2558054Y2 - Engine starter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine starting device used for facilitating starting of an engine such as a small portable work machine.

[0002]

2. Description of the Related Art When a cold engine is started, the start of the engine is facilitated by increasing the mixing ratio of gasoline to air, that is, by decreasing the air-fuel ratio (thickening) until the engine is warmed. Can be. For this reason, more specifically, the engine is caused to inhale a larger amount of fuel or the amount of intake air is reduced by a choke operation (hereinafter, referred to as a choke operation). Recently, various measures for automating such a choke operation (hereinafter, referred to as an auto choke operation) have been proposed. For the purpose of automating the choke operation, the state of the engine, that is, whether the engine is being started or not is determined. Must be determined, and this determination is made, for example, as follows. That is, in the case of (a) the cell starter starting device, it is determined that the start operation is being performed when a current is flowing through the cell starter. In the case of a starting device such as (b) a recoil starter, the operator can set the starting position arbitrarily by a mechanical switch so that the starting operation can be performed, and a mechanical switch is provided in the starting device. When the switch is turned on during the starting operation, it is determined that the starting operation is being performed.

[0003]

Since the conventional engine starter is configured as described above, it is determined that the current is flowing to the starter motor of the cell starter during starting, and the automatic choke operation is performed. In such a case, if the rotation speed of the starter motor is low, such as when the capacity of the battery is low, or if the magnet ignition device does not operate due to an operator's operation error, the rich mixture in the engine will In some cases, a large amount of the fuel is inhaled, so that the fuel becomes liquid and stays in the engine, and an optimum air-fuel mixture is not formed.

[0004] On the other hand, in the method in which the operator sets the starting position by using a mechanical switch, if the starting position is not set due to an operator's mistake, the choke operation is not performed.
If the engine does not start at all, and if the user forgets to switch the switch from the starting position to the operating position after the engine is started, the choke operation remains active, the operating state of the engine becomes unstable, and CO and HC Generation of
In some cases, the amount of exhaust gas increases, resulting in deterioration of the environment, and furthermore, an unusable state. Further, there is a problem that the operation of switching the switch between start, operation, and stop and each time is complicated.

Further, when a mechanical switch is incorporated in a starting device, it cannot be easily incorporated into a starting device currently used, and each starting device must be newly manufactured so as to correspond to the mechanical switch. In addition, since the structure of the starting device is complicated, the cost is increased and there is a problem in durability.

The present invention has been made to solve the above-mentioned problems, and it is possible to reliably start the engine and to provide an inexpensive engine whose starting operation and structure are simple and which can be provided at low cost. It is intended to provide a starting device.

[0007]

An engine starting device according to the present invention includes an integrating circuit for integrating an ignition pulse output in synchronization with rotation of the engine, and an output signal of the integrating circuit which is a predetermined input signal. A waveform shaping circuit that outputs a signal of a set level at a timing exceeding the judgment level; and a timer circuit that outputs an output signal of a fixed time width based on the output signal of the waveform shaping circuit. receiving, in the load control circuit, during said predetermined time, ene
The current is supplied to the starting fuel supply device until the set temperature of the gin is detected .

[0008]

According to the load control device of the present invention, when the rotation speed of the engine exceeds a certain value, a current flows through the solenoid for the solenoid valve of the fuel supply device only for a certain period of time. By increasing the air-fuel ratio, the start of the engine is promoted. In this case, when the rotation speed of the engine becomes sufficiently high and the temperature of the engine exceeds a set value, the current supply from the load control device to the solenoid for solenoid valve is cut off by the temperature control circuit. Irrespective of the time period, the excess fuel supply to the engine is automatically stopped so that the normal operation mode is immediately entered.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral A denotes an ignition device, which includes a flywheel 7 in which a magnet or the like that rotates in synchronization with the rotation of the crankshaft of the engine is embedded, an ignition coil 8 that induces an ignition voltage by the magnet, and an ignition timing control. An ignition control unit 9 for performing ignition control and an ignition plug 10 for generating a spark and igniting a fuel gas are provided. 1
Is an integration circuit for detecting an ignition pulse generated in the primary coil 8a of the ignition coil 8 and integrating the detected ignition pulse. As shown in FIG. 2, the integrating circuit 1 has a current limiting resistor 12, a backflow preventing diode 13, an overvoltage preventing diode 15, a capacitor 14, an overvoltage preventing zener diode 16 and a resistor 17, each of which is wired as shown in the drawing. Consists of

Reference numeral 2 denotes a waveform shaping circuit for shaping the output signal of the integrating circuit 1, and a knot gate IC 18 is connected as shown in FIG. 2 as shown in FIG. The knot gate is not limited to the knot gate IC 18 but may be formed by another gate IC, and a comparator IC or the like is also used. Reference numeral 3 denotes a timer circuit for outputting an output signal for a predetermined time based on the signal of the waveform shaping circuit 2. As shown in FIG. 2, a timer IC 19, a resistor 20, and a capacitor 2 are provided.
1, 22, 23 and a variable resistor 24 are connected as shown in FIG.
A one-shot multivibrator that outputs a high-level signal for a certain period of time determined by the time constant of 4. In addition, using electronic parts such as transistors,
A one-shot multivibrator similar to the above can also be configured.

Further, 4 receives a signal output from the timer circuit 3 and receives a load 5 as a starting fuel supply device for a fixed time.
(For example, a load control circuit for flowing a current to a solenoid coil 11 such as an electromagnetic valve for controlling the supply of fuel only at the time of starting). As shown in FIG. 2, a current limiting resistor 25 and a transistor 26 are wired as shown in FIG. Connected. In the load control circuit 4, reference numeral 6 denotes a temperature control circuit having a temperature detector for detecting a temperature state of the engine. When the temperature control circuit 6 is higher than a set temperature, the temperature control circuit bypasses the output signal of the timer circuit 3 and cuts off the current flowing through the load 5. It comprises a temperature-sensitive resistance element 28 such as a thermistor. That is, the output of the timer circuit 3
Receives force signal and detects engine set temperature for a certain period of time
Until then, supply current to the starting fuel supply device
I have. The temperature-sensitive resistance element 28 is connected between the base and the emitter of the transistor 26 of the load control circuit 4, and is installed near an engine cylinder or a carburetor (not shown). When using another temperature-sensitive resistance element, it is necessary to make a circuit configuration according to its characteristics. 27
Is a battery used as a power supply.

Next, the operation will be described. First, when the engine is started by a cell starter or recoil starter in a small portable work machine or the like, the flywheel 7 rotates in the direction of the arrow, and the ignition unit 9 is driven by the induced voltage induced by the primary coil 8a of the ignition coil 8. Operates.
On the other hand, a high voltage is generated in the secondary coil 8b, a spark is generated in the spark plug 10, the fuel gas is ignited, and the engine starts to start. At this time, the ignition pulse voltage shown in FIG. 3A is input from the primary coil 8a of the ignition coil 8 to the current limiting resistor 12 of the integration circuit 1. The current limiting resistor 12 enables an ignition pulse voltage in which the current is limited to be obtained.
The ignition pulse voltage is charged. Then, discharge is performed via the resistor 17 with a time constant determined by the capacitor 14 and the resistor 17, and as a result, an output voltage having an integrated waveform as shown in FIG. 3B is obtained. In this embodiment, the ignition pulse is generated only once as shown in the drawing with one rotation of the flywheel 7, so that the voltage level of the integration circuit 1 is such that the flywheel 7 rotates several times and the rotation speed does not increase. Does not exceed the set voltage level of the next waveform shaping circuit 2. Now, when the flywheel 7 rotates several times and the rotation speed increases, the ignition pulse voltage is charged in the capacitor 14 of the integration circuit 1 and the voltage level discharged through the resistor 17 is as shown in FIG. The voltage level V as an input determination level of the knot gate IC 18 of the next-stage waveform shaping circuit 2
rises above th. Therefore, the output signal of the knot gate IC 18 of the waveform shaping circuit 2 changes from a low level (0 volt) to a high level (substantially the power supply voltage) when the voltage level exceeds the voltage level Vth, as shown in FIG. stand up.

On the other hand, the knot gate IC of the waveform shaping circuit 2
Based on the output signal of No. 18, the next-stage timer circuit 3
At a time T determined by the time constant of the capacitor 23 and the variable resistor 24, a high-level signal as shown in FIG. During the fixed time T, a current flows between the base and the emitter of the transistor 26 through the current limiting resistor 25 of the load control circuit 4 so that the output signal of the timer circuit 3 is turned off. 26 is turned on, a pulse current for a certain time T flows between the collector and the emitter, and a current flows to the solenoid coil 11 of the solenoid valve which is the load 5. As a result, opened by a predetermined time the electromagnetic valve T (e.g. about one second), the fuel is supplied to the vaporizer, the liquid gas in the engine fuel supply becomes excessive
The engine can be started and the operation can be continued with a slightly higher air-fuel ratio while avoiding stagnation as sorin . Therefore, there is no need to operate the choke valve and the choke lever, and anyone can start the engine quickly and reliably regardless of the battery capacity.

When the work is performed to some extent using a small portable work machine, the temperature near the engine cylinder or the carburetor rises. Then, such a temperature state of the engine changes to a set temperature (for example, about 50 °).
C) If the air-fuel ratio is slightly increased as in the case of starting when the temperature rises above, as described above, if the magnet ignition device does not operate, the engine may be started due to the stagnation of the fuel in a liquid state or the like. It can be difficult. However, in such a case, the temperature-sensitive resistance element 28 of the temperature control circuit 6 disposed near the cylinder or the carburetor of the engine has a low resistance value, and the output signal of the timer circuit 3 is bypassed to the ground side. Will be done. For this reason, the collector and the emitter of the transistor 26 are turned off, and the current flowing through the solenoid coil 11 of the solenoid valve as the load 5 is also cut off. As a result, the solenoid valve is closed, and the amount of fuel that provides an appropriate air-fuel ratio is supplied to the carburetor, so that restart can be easily performed. When the temperature of the engine is equal to or lower than the set temperature, the resistance value of the temperature-sensitive resistance element 28 becomes a high resistance value, so that the output signal from the timer circuit 3 is not bypassed to the ground side.
Therefore, between the collector and the emitter of the transistor 26 is turned on, a current flows through the solenoid coil 11, and the solenoid valve is opened for a certain time.

[0015]

As described above, according to the present invention, an integrating circuit for integrating an ignition pulse output in synchronization with rotation of an engine, and an output signal of the integrating circuit exceeding an input judgment level set in advance. A waveform shaping circuit that outputs a signal of a set level at a predetermined timing, and a timer circuit that outputs an output signal having a fixed time width based on the output signal of the waveform shaping circuit. the load control circuit, during said predetermined time, setting of the engine temperature detected or
Since it is configured to supply current to the starting fuel supply device, when it is determined that the cell motor of the cell starter is operating and the auto choke operation is performed, the choke operation is performed only for a predetermined period of time, A large amount of the rich air-fuel mixture is sucked into the engine, and the engine does not fall into a difficult-to-start state.

In the case of a method in which the operator performs a starting operation by a mechanical switch, the choke operation is performed completely automatically by using a signal from the magneto ignition device.
It is possible to obtain an effect that the operation error of the operator is not caused, the engine does not fall into an unusable state while the choke operation is performed, and further, the setting change operation of the switch becomes unnecessary.

In addition, the function can be achieved simply by connecting to the connection between the magnet ignition device currently used and the engine stop switch, and the device can be mounted only in a vacant part of the engine, so that it is relatively simple. In addition, the use of an electric switch such as a semiconductor switch also reduces the cost, and the life is improved compared to a mechanical switch, so that semi-permanent durability can be obtained.

Further, by detecting the temperature state of the engine, it is possible to obtain an effect that the air-fuel ratio can be accurately controlled at the time of starting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an engine starting device according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing the inside of each block of FIG. 1 in detail.

FIG. 3 is a voltage waveform diagram of each part of the electric circuit diagram shown in FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 integration circuit 2 waveform shaping circuit 3 timer circuit 4 load control circuit 5 starting fuel supply device (load) 6 temperature control circuit

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiki Kitamura 1-1114 Oppama Honcho, Yokosuka City, Kanagawa Prefecture Inside Oppama Industry Co., Ltd. (56) References JP-A-58-199071 (JP, A) JP-A-61 129436 (JP, A) JP 60-14185 (JP, B2)

Claims (1)

(57) [Scope of request for utility model registration] 1. An integration circuit for integrating an ignition pulse output in synchronization with rotation of an engine, and an output signal of the integration circuit.
Exceeds the preset input judgment level
A waveform shaping circuit for outputting a setting level of the signal, and a timer circuit for outputting an output signal of a predetermined time width based on the output signal of the waveform shaping circuit, receiving the output signal of said timer circuit, during the previous year period of time, Until the set temperature of the engine is detected
Is a load control circuit for supplying a current to the fuel supply device for starting the engine.