JPS6275075A - Reversion preventing device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent generation of a kickback simplifying constitution, by utilizing counter electromotive force, generated by an electric starting motor reversed when an engine reversely rotates, and generating misfiring in the engine so that the necessity for changing a material quality of constitution parts in a layout of the engine and its start driving system is eliminated. CONSTITUTION:When an engine reversely rotates, counter electromotive force is generated in an electric circuit by reversing an electric starting moor 18. Said counter electromotive force, decreasing a base current value in the first transistor 24 to turn off the first transistor 24, causes the second transistor 26 to be turned on, and an electric current is placed in a condition that it is allowed to flow in an ignition coil 10. Under this condition, even if, for instance, an off-signal of igniter 8 is input, the engine generates misfiring by preventing a spark plug 12 from sparking because the second transistor 26 is turned on. Accordingly, the necessity for changing a material quality of constitutional parts in a layout of the engine and its start driving system is eliminated, and the engine, only connecting a control circuit 22, enables generation of a kickback to be prevented by a device simplifying its constitution with a cheap cost.

Description

Detailed Description of the Invention [Industrial Application Field] This invention relates to a reverse rotation prevention device for an internal combustion engine, and in particular, it prevents kickback (
The present invention relates to a reverse rotation prevention device for an internal combustion engine that can prevent the occurrence of kickback.

[Prior Art] To start an internal combustion engine, the crankshaft must be rotated by an external force until the required constant rotation is maintained in order to draw in, atomize, compress and explode the fuel. A starter motor is used to rotate this crankshaft. This starter motor has a configuration in which a pinion meshes with a ring gear fitted to the outer periphery of a flywheel of an internal combustion engine, so that the pinion can move back and forth on a shaft. Further, some starter motors have a one-way clutch that is always engaged, and a pinion and a ring gear that are engaged except when the internal combustion engine rotates in the forward direction.

The ignition system of the internal combustion engine is shown in Figures 3(a) and 3(b).
) As shown in FIG.
have. Since this device cannot determine whether the internal combustion engine is rotating in the forward or reverse direction, the spark plug 12 will spark even if the engine is in the reverse rotation position (see FIG. 4).

Problems to be Solved by the Invention] Incidentally, in an internal combustion engine with a single cylinder or two cylinders and a large single displacement, rotational fluctuations are large and the rotational speed of the internal combustion engine at the instant of ignition decreases. For this reason, the piston may not be able to overcome the compression force of the air-fuel mixture generated in the cylinder during the compression stroke, and may be forced back. At this time,
Reverse rotation starts at the (X) position in Figure 2, and this (X
) If the spark plug 12 flies off at the (Y) position 551 Ilsec after the position, the reverse rotation produces an abnormal noise and kickback occurs. Therefore, a strong impact acts on the components of the starting drive system, such as the starter motor and the idle gear, and this strong impact causes the above-mentioned components to be damaged. In order to solve this problem, efforts have been made to strengthen the components, but this requires changes to the layout of the internal combustion engine and the materials of the components, making the construction complicated and increasing costs. Furthermore, even though the strength of the component parts has been strengthened in this way, there is a risk that the component parts will be damaged. Further, as a device for causing a misfire when the internal combustion engine rotates in reverse, there is, for example, one disclosed in Japanese Patent Laid-Open No. 137364/1983. This device prevents reverse rotation of the internal combustion engine from low speed to high speed by using a first signal and a second signal that is shifted by θ° with respect to the first signal.

[Object of the Invention] Therefore, the object of the present invention is to eliminate the above-mentioned disadvantages and improve the layout and component parts of the internal combustion engine by causing a misfire using the back electromotive force generated by the starting motor when the engine rotates in reverse. To provide a reverse rotation prevention device for an internal combustion engine that does not require a change in material, has a simple configuration, and can be made at low cost to prevent the occurrence of kickback.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a reverse rotation prevention device for an internal combustion engine that causes normal ignition when the internal combustion engine rotates in the forward direction and misfires when the engine rotates in the reverse direction. Otherwise, when the internal combustion engine is provided with a constant-mesh type starting motor and rotates in reverse, the starting motor is driven in reverse rotation by the reverse rotational force of this internal combustion engine, and the control circuit causes a misfire by using the back electromotive force generated by the starting motor. It is characterized by having the following.

[Operation] According to the configuration of the present invention, when the internal combustion engine rotates in reverse, the starter motor is driven to rotate in reverse by the reverse rotation force of the internal combustion engine to generate a back electromotive force, and this back electromotive force is supplied to the control circuit. ,
This prevents the occurrence of flying sparks from the spark plug, causing the internal combustion engine to misfire.

As a result, there is no need to change the layout of the internal combustion engine or the material of the component parts, and the structure is simple and inexpensive, preventing kickback of the internal combustion engine and extending the service life of the internal combustion engine and the components of the starting drive system. Lengthen.

[Embodiments of the Invention] Examples of the present invention will be described in detail and specifically below based on the drawings.

Figure 1.2 shows an embodiment of the invention. In the figure, 2 is an ignition signal detection section, and this ignition signal detection section 2 has a timing rotor 4 and a pickup coil 6. The ignition signal detection section 2 is in communication with an igniter 8. A spark plug 2 is connected to the igniter 8 via an ignition coil 10. Further, the igniter 8 is connected to a starter relay 16 via a starter switch 14. This starter relay 1
6 is in communication with the starter motor 18. This starter motor 18 has a constant mesh mechanism and is connected to the internal combustion engine except when the internal combustion engine rotates in the forward direction.

Further, a battery 20 is connected to the starter relay 16 .

The igniter 8 also includes a control circuit that prevents the spark plug 12 from sparking and misfires using a back electromotive force generated by the reverse rotation of the starter motor 18 when the internal combustion engine (not shown) rotates in reverse. 22 is in contact. This control circuit 22 has first and second transistors 24 and 26.

The base of this first transistor 24 is connected to the starter switch 14 via a first resistor 28, and
The starter relay 16 and the starter motor 18 are connected through a second resistor 30 and a diode 32, which are provided in parallel with the first resistor 28.

The collector side of the second transistor 26 is connected between the igniter 8 and the ignition coil 10. The base of the second transistor 26 and the collector of the first transistor 24 are in communication via a third resistor 34. Furthermore,
The collector side of the first transistor 24 is connected between the first resistor 28 and the starter switch 24 via a fourth resistor 36 .

Hereinafter, the operation of the embodiment of this invention will be explained.

During forward rotation of the internal combustion engine, the control circuit 22 is connected to the battery 20.
The electromotive force from the starter switch 14 is supplied, and the current
The current flows from the side to the first transistor 24 side via the first resistor 28. Then, this current flows from the base to the emitter of the first transistor 24 and also flows to the collector side of the first transistor 24 via the fourth resistor 36. This first transistor 24 is turned on. When the first transistor 24 is turned on, the second transistor 26 is turned off, thereby causing the igniter 8 to operate normally. At this time, the starter motor 18 is not connected to the internal combustion engine because the meshing mechanism is released.

When the internal combustion engine is rotating in reverse, the starter motor 18 is connected to the internal combustion engine. As a result, the starter motor 18 is driven to rotate in the reverse direction by the reverse rotational force of the internal combustion engine, so that a back electromotive force is generated as shown in FIG.

That is, as the starter motor [18 on the driven side rotates in the reverse direction, a back electromotive force having a polarity opposite to the power supply voltage is generated in the electric circuit. This back electromotive force is generated by the first transistor 24
This first transistor 2
Turn off 4. Coupled with this turning off of the first transistor 24, the second transistor 26 is turned on, and current flows into the ignition coil 10. In such a state, even if the igniter 8 off signal is input at point A in FIG. 2, since the second transistor 26 is on, it will prevent sparks from flying out from the spark plug 12 at point A. Misfire the internal combustion engine.

As a result, there is no need to change the layout of the internal combustion engine or the materials of the components of the starting drive system, and by simply connecting the control circuit 22, the configuration is simple, the cost is low, and kick hacks are prevented.

Therefore, damage to the internal combustion engine and the above-mentioned components is avoided and the service life is extended.

[Effects of the Invention] As is clear from the detailed explanation above, according to the present invention,
By using the back electromotive force generated by the starter motor, which rotates in reverse due to the reverse rotational force of the internal combustion engine when the internal combustion engine rotates in reverse, the internal combustion engine misfires. To eliminate the need for changes, to have a simple configuration, to reduce costs, and to prevent the occurrence of kickback. This can extend the service life of the internal combustion engine and the components of the starting drive system.

[Brief explanation of drawings]

1.2 shows an embodiment of the present invention, FIG. 1 is a circuit diagram of a reverse rotation prevention device, and FIG. 2 is a time chart of an ignition system. FIGS. 3(a) and 3(b) are partial schematic diagrams of a conventional ignition system,
FIG. 4 is a time chart of a conventional ignition system. In the figure, 2 is an ignition signal detection unit, 8 is an igniter, 1
2 is a spark plug, 18 is a starter motor, 22 is a control circuit,
24 is a first transistor, and 26 is a second transistor.

Claims (1)

[Claims] In a reverse rotation prevention device for an internal combustion engine that causes normal ignition when the engine rotates in the forward direction and misfires when the engine rotates in the reverse direction, the internal combustion engine is equipped with a constant-mesh starting motor except when the engine rotates in the forward direction. A reverse rotation prevention device for an internal combustion engine, comprising a control circuit that drives the starter motor in reverse rotation by rotational force and causes a misfire by using a back electromotive force generated by the starter motor.