JPS6115256Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a starter protection device for an internal combustion engine installed in a vehicle such as an automobile.

In general, a DC voltage generator that charges an on-vehicle power storage device includes an alternating current generator that generates voltage according to the rotation of an internal combustion engine, and a full-wave rectifier circuit that converts the generated voltage into direct current. A starter protection device for an internal combustion engine protects the starter when the operating state of the internal combustion engine, that is, the detection level of a pulse signal proportional to the voltage generated by the alternator or the rotational speed of the internal combustion engine, exceeds a preset level. It functions to stop the operation.

However, when the internal combustion engine is started under low temperature conditions, its rotational speed fluctuates extremely and the voltage generated by the alternator pulsates, so that the starter protection device is activated by detecting an unstable peak value. This causes the inconvenience that the starter protection device is activated before the internal combustion engine is completely detonated, and the internal combustion engine is not started.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable starter protection device for an internal combustion engine that can eliminate the above-mentioned drawbacks.

This invention also allows the starter key switch to
The purpose of the present invention is to provide a highly reliable starter protection device that also has a function to prevent the starter from re-entering, that is, from restarting the starter when the internal combustion engine enters an irregular ignition state while the starter is in the ON state. There is.

The present invention will be described in detail below with reference to illustrated embodiments.

The figure mainly shows a starter 1, a voltage regulator 2, a DC voltage generator 3, a capacitor 4, and a starter protection device 5 of an internal combustion engine.

When the key switch 6 of the starter is turned on, the output voltage of the capacitor 4 is applied to the base of the first transistor Q ₁ via the resistor R ₁ ,
_Q1 conducts. As a result, a current flows through the coil _L1 of the relay device 7, and the contact _CT1 becomes closed. At the same time, the output voltage of the capacitor 4 is also applied to the base of the second transistor Q ₂ via the coil L ₁ and the resistor R ₂ of the relay device, but due to the charging action of the capacitor C, the transistor Q ₂ conduction is prevented, ensuring that transistor _Q1 remains conductive.

When the contact CT ₁ of the relay device 7 is in the closed state, current flows through the coils L ₂ and L ₃ of the relay device 8 of the starter 1, and the contact CT ₂ thereof is brought into the closed state. Furthermore, the coil
L ₂ is the contact actuation coil and coil L ₃ is the contact holding coil. As a result, the motor M of the starter 1 rotates, causing the internal combustion engine (not shown) to start rotating.

On the other hand, when the internal combustion engine starts rotating, the output of the capacitor 4 is applied to the field winding W ₁ of the alternator via the field resistance R ₄ . The initial excitation current of the field winding W ₁ energizes the three-phase star generator winding W ₂ of the alternating current generator to start generating electricity.

As the rotational speed of the internal combustion engine increases, the voltage generated by the alternator also increases, and this generated voltage is passed through a full-wave rectifier circuit 9 made up of six diodes.
It is taken out as the output of the DC voltage generator 3 in order to charge the capacitor 4. The generated voltage of the AC generator is also transmitted to the DC voltage generator 3 as a detection output via an auxiliary diode circuit 10 consisting of three diodes, which is a so-called auxiliary diode system.
is output from. This detection output is the voltage regulator 2
and a smoothing circuit consisting of a resistor _R3 and a capacitor C.
Applied as a reverse voltage to diode ZD. This smoothing circuit prevents the Zener diode ZD from breaking down due to the unstable peak voltage when the internal combustion engine is started under low temperature conditions and the rotational speed fluctuates extremely and the generated voltage of the alternator pulsates. In order to prevent this, it functions to smooth out the pulsating voltage and lower the peak voltage. As will be described later, this means that the starter protection device is prevented from operating before the internal combustion engine completely explodes.

When the smoothed detection output exceeds a certain predetermined level, in other words when the internal combustion engine enters a normal stable operating condition, the Zener diode
The breakdown of ZD causes the sensing output to be applied to the base of transistor _Q2 , making it conductive. Therefore, transistor Q ₁ becomes non-conducting and
Contact CT ₁ of relay device 7 becomes open. As a result, the contact CT ₂ of the relay device 8 of the starter 1 becomes open, the rotation of the motor M stops, and the operation of the starter 1 ends.

If, under such conditions and the key switch 6 remains ON, irregular ignition of the internal combustion engine occurs, the rotation of the internal combustion engine will decrease and the voltage generated by the alternator will decrease, causing the starter to The detection output applied to the Zener diode ZD of the protection device 5 decreases. This prevents the sense output from being applied to the base of transistor Q ₂ , rendering this transistor non-conducting and disabling transistor Q ₁
becomes conductive, causing starter 1 to operate again, causing the starter to jump again.

However, according to the invention, the collector of transistor Q ₁ is connected to the base of transistor Q ₂ via resistor R ₂ . Therefore, even if the detection output decreases as described above during irregular ignition of the internal combustion engine, the collector potential remains at a high level due to the non-conduction of transistor _Q1 , and this potential
Since it continues to be applied to the base of transistor Q ₂ through R ₂ , transistor Q ₂ remains conductive. In this way, transistor Q ₂ is maintained in a conductive state regardless of the decrease in the detection output.
This means that the transistor Q ₁ is kept non-conducting to prevent the starter 1 from operating, thus effectively preventing starter re-jumping.

As described above, according to the present invention, by using an inexpensive smoothing circuit composed of a resistor and a capacitor, the starter protection device reliably controls the operation of the starter even when the internal combustion engine is started under low temperature conditions. be able to.

Furthermore, according to the present invention, the collector potential of the first transistor _Q1 included in the starter protection device is simply applied to the base of the second transistor _Q2 , which is an extremely simple and inexpensive connection configuration.
It is possible to reliably prevent the starter from flying back in when the internal combustion engine is ignited incorrectly.

[Brief explanation of the drawing]

The figure shows a specific circuit showing the starter protection device of the present invention and a device connected thereto. Symbol explanation, 1: Starter, 2: Voltage regulator,
3: DC voltage generator, 4: Condenser, 5: Starter protection device, 6: Key switch, 7, 8: Relay device, 9: Full wave rectifier circuit, 10: Auxiliary diode circuit, R ₁ to _{R 4} : Resistor , L ₁ ~ _{L 3} : Coil, CT ₁ ,
CT ₂ : Contact, Q ₁ , Q ₂ : Transistor, ZD: Zener diode, M: Motor, W ₁ : Field winding, W ₂ : 3-phase star generator winding, C: Capacitor.

Claims (1)

[Scope of utility model registration request] When the key switch of the starter of the internal combustion engine is in the ON state, the output from the capacitor is applied to the base of the first transistor to make the first transistor conductive and energize the relay device connected to the collector thereof. The operation of the starter is started, and a detection output indicating the operating state of the internal combustion engine is applied to a Zener diode, and when the detection output exceeds a predetermined level, the breakdown of the Zener diode causes the detection applying an output to the base of a second transistor whose collector is connected to the base of the first transistor to cause the second transistor to conduct and to render the first transistor non-conductive; In the starter protection device that deenergizes the relay device to stop the operation of the starter, the detection output is applied to the Zener diode via a smoothing circuit including a first resistor and a capacitor, and further,
When the detection output drops below the predetermined level due to irregular ignition of the internal combustion engine, applying the collector potential of the first transistor to the base of the second transistor via a second resistor. A starter protection device characterized in that the second transistor is maintained conductive, thereby rendering the first transistor non-conductive.