JPH05155296A - Automotive power supply circuit - Google Patents

Abstract

PURPOSE:To supply a voltage of 24V to a starting motor when an internal combustion engine is started by providing two batteries with a rated voltage of 12V, and connecting them in series automatically in response to a starting switch when a starting motor is driven and connecting in parallel in other cases, to supply mainly a voltage of 12V to electrical equipment. CONSTITUTION:Two batteries A and B with a terminal voltage of 12V are provided, a rated voltage of a starting motor M is set at 24V, and a rated voltage of a generator G is set at 12V. Also a rotating shaft of the starting motor M is connected mechanically to the rotating shaft of an internal combustion engine by the operation of a starter switch, and an engage switch ESW including a No.1 contact M1 which connects a starting motor M mechanically to a secondary battery is provided. Then a No.1 switch-over contact M2 which is interlocked with the No. contact M1 of the engage switch ESW is provided and, when the engage switch ESW is in drive condition, the batteries A and B are connected in series and, when it is in open condition, the batteries A and b are connected in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile battery, a starter motor, a charging generator, various electric devices, and a power supply circuit connecting them.

The present invention is used for a large automobile which requires a high voltage (24V) as a rated voltage of a starting motor.

[0003]

2. Description of the Related Art Conventionally, a large motor vehicle, especially a motor vehicle using a diesel engine, requires a high output as a starting motor for an internal combustion engine. Therefore, the starting motor has a high rated voltage (24V, not strictly 24V). Although a certain voltage range is set, it is used as 24V in this specification). Therefore, the secondary battery and other electric equipment installed in the automobile are designed to be adjusted to 24V. On the other hand, in the widespread passenger cars, the starting motor has a low rated voltage (12V, strictly 12V).
However, a certain voltage range is set, but this is indicated as 12V in this specification) is sufficient, and the rated voltage of the secondary battery and all other electrical equipment to be equipped is 12V.

[0004]

The unit price of electric devices having a rated voltage of 12V is mass-produced for electric devices equipped in electric vehicles such as light bulbs, generators, wipers, control computers, radios and stereo devices, and other vehicles. Voltage is 2
It is considerably smaller than the 4V type. Therefore, the price of electric equipment increases in a large vehicle having a rated voltage of 24V. In addition, although there are many kinds of specifications of electric devices having a rated voltage of 12V, those having a rated voltage of 24V are limited. For example, the rated voltage of an electric device is 24V
It is necessary to use a DC-DC converter even when trying to attach a stereo device of interest to a large automobile, which increases cost and requires space.

Conventionally, in order to solve this problem, in a large-sized automobile, two secondary batteries having a rated voltage of 12V are used in series connection and 12V supplied to various electric devices at the connection point.
It is known that terminals are provided. In this case, an extra current is taken out from one of the two secondary batteries connected in series, so that one of the batteries is consumed. This shortens battery life and complicates battery maintenance.

In order to avoid this, two serially connected
A circuit in which various electric devices having a rated voltage of 12V are dispersedly connected to each of the individual batteries, and connection switching is performed to one of the two batteries while monitoring the current consumption of the battery for a part of the electric device. Are also known.

However, in these circuits, one of the secondary batteries connected in series inevitably becomes exhausted, and in the circuit for switching the connection, the power supply circuit of the power supply circuit whose rated voltage is 12 V is supplied. Since one end does not always have the ground potential, it imposes a complicated restriction on the circuit of the electric device. Further, a current monitoring circuit and a changeover switch controlled by the monitoring circuit are required, and these become expensive, and these circuits may create a new cause of failure.

Further, in the circuit involving switching, there is a short time at the moment of switching, but the power supply current is interrupted,
This has a bad influence on various control circuits having a built-in microcomputer, which have been installed in many automobiles in recent years.

The present invention has been made against such a background. (1) The rated voltage of the starting motor is 24V,
(2) The rated voltage of the generator and other electric devices installed in the vehicle is 12V, (3) even if the battery is divided into two, the same current consumption can be obtained from each battery, and (4) each battery Can be given a charging current equal to (5)
One terminal of an electric device having a rated voltage of 12V is always at ground potential, and (6) a power supply circuit for an automobile is provided in which the power supply current supplied to a load terminal is not interrupted even during a short connection switching time. The purpose is to do.

[0010]

The present invention provides a secondary battery,
A generator driven by an internal combustion engine for driving an automobile to charge the secondary battery, a starter motor for starting the internal combustion engine, a starter switch operated by a driver, and the starter driven by operating the starter switch. An engagement switch including a first contact for mechanically connecting a rotating shaft of an electric motor to a rotating shaft of the internal combustion engine and electrically connecting the starting electric motor to the secondary battery, and an electric device mounted on the vehicle. In a vehicle power supply circuit having a load terminal for supplying a power supply current, the secondary battery includes two batteries having the same terminal voltage (12V), and the starter motor has a rated voltage twice as high as the terminal voltage. Voltage (24V)
The rated voltage of the generator is equal to the terminal voltage (12V), and a switching contact that interlocks with the first contact is provided, and the two batteries are connected in series when the engagement switch is driven. A connection is provided between the two batteries and the switching contact so that the two batteries are connected in parallel when the engagement switch is open, and the generator and the load terminal are connected. Is the above 2
It is characterized in that it is permanently connected to the terminal of the first battery of the individual batteries.

The connection connects the ground potential (-) side terminal of the first battery of the two batteries to the ground potential, and the non-ground potential (+) side terminal of the switching contact. Connected to the drive contact, the ground potential (-) side terminal of the second battery of the two batteries is connected to the common contact of the switching contacts, and the non-ground potential (+) side terminal is connected to the first contact. It is desirable that the engagement switch is connected to one contact and the release contact of the switching contact is connected to the ground potential, and that the engagement switch includes a driving coil and a holding coil therein, and a second switching that interlocks with the first contact. A contact is provided, a common contact of the second switching contact is connected to a terminal on the non-ground potential (+) side of the first battery, and a drive contact is a terminal on the ground potential (-) side of the second battery. And the release contact is the end of the second battery on the non-ground potential (+) side. Further, a relay having a voltage (12 V) equal to the terminal voltage as a rated voltage is provided, and one end of a coil of the relay is connected to the non-ground potential (+) side of the first battery via the start switch. The other end of the coil of the relay is connected to the non-grounded side terminal of the starting motor through a backflow prevention diode, and the common terminal of the drive coil and the holding coil is connected to one end of the coil of the relay. The drive coil terminal is connected to one end of the relay contact, the other end of the contact and the holding coil terminal are connected to the ground potential, respectively, and the first switching contact and the second switching contact are connected to each other. It is desirable that the contact is a mechanical contact with the first contact of the engagement switch.

[0012]

In the power supply circuit of the present invention, two batteries having a rated voltage of 12 V are provided, which are automatically connected in series in response to the start switch when driving the starting motor, and are automatically connected in parallel at other times. It The load terminals that connect the generator and various electric devices are connected in parallel to the voltage 1
2V is the rated voltage. That is, the electrical device is inexpensive and allows a wide variety of choices. Further, the engagement switch, which is generally integrated with the internal combustion engine and the starting motor, can be dealt with by a simple design change.

According to the present invention, the load terminal (L1, L2,
Since L2) is permanently connected to the first battery (A), the power supply voltage is not interrupted during that time.
Therefore, the control circuit including the microcomputer can be continuously operated by connecting to the load terminal.
This short time may result in a slight non-uniform consumption of the two cells, but immediately after the short time the two cells are connected in parallel for a long time, which results in non-uniformity. Exhaustion will be replenished immediately and will not be a problem.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of the embodiment of the present invention.

In the embodiment of the present invention, a secondary battery, a generator G driven by an internal combustion engine for driving an automobile to charge the secondary battery, a starter motor M for starting the internal combustion engine, and a driver are operated. And a first contact for mechanically connecting the rotating shaft of the starting electric motor M to the rotating shaft of the internal combustion engine and electrically connecting the starting electric motor M to the secondary battery driven by the operation of the starting switch SSW. An engagement switch ESW including M1 and load terminals L1 and L2 for supplying a power supply current to an electric device mounted on the vehicle are provided. Further, as a feature of the present invention, the secondary battery has a terminal voltage (12V). The same number of batteries A and B are included, the rated voltage of the starting motor M is twice the terminal voltage (24 V), and the rated voltage of the generator G is the terminal voltage. Equal voltage (12V), the push rod 1 is provided with a switching contact M2 so as to interlock with the first contact M1, the return spring 2 is provided at the tip thereof, and two rechargeable batteries are provided when the engagement switch ESW is driven. In order to connect A and B in series and to connect the two secondary batteries A and B in parallel when the engagement switch ESW is in a released state, the two secondary batteries A and B and the first switching contact M2 are connected. The generator G and the load terminals L1 and L2 are permanently connected to the terminals of the first battery A of the two secondary batteries A and B.

Further, the connection connects the terminal on the ground potential (-) side of the first battery A of the two secondary batteries A and B to the ground potential, and connects the terminal on the non-ground potential (+) side. The terminal is connected to the drive contact a of the first switching contact M2, and the terminal on the ground potential (-) side of the second battery B of the two secondary batteries A and B is connected to the first switching contact M2. Of the first switching contact M2 and the release contact b of the first switching contact M2 are connected to the ground potential.

Further, the engagement switch ESW includes a drive coil C1 and a holding coil C2 therein, a second switching contact M3 interlocking with the first contact M1, and a common contact e of the second switching contact M3. f is connected to the non-ground potential (+) side terminal of the first battery A, the drive contact g is connected to the ground potential (−) side terminal of the second battery B, and the release contact h is the second. A relay R connected to a terminal on the non-ground potential (+) side of the battery B and having a voltage (12 V) equal to the terminal voltage as a rated voltage is provided, and one end of a coil of this relay R is connected via a starting switch SSW. Is connected to the terminal on the non-grounded potential (+) side of the first battery A, and the other end of the coil of the relay R is connected to the non-grounded side terminal of the starting electric motor M via the backflow prevention diode D, and the drive coil Both C1 and holding coil C2 Terminal is connected to one end of the coil of the relay R, the contact r terminal of the driving coil C1 relay R
The other end of the contact r and the terminal of the holding coil C2 are connected to the ground potential, respectively, and the first switching contact M2
And the second switching contact M3 is an engagement switch ESW
Is a contact mechanically interlocked with the first contact M1.

Next, the operation of the embodiment of the present invention thus constructed will be described.

FIG. 2 is a circuit diagram showing a normal state in the embodiment of the present invention. In normal times, that is, during traveling, the push rod 1 is pressed by the return spring 2, so the first contact M1 is in the open state, and the first switching contact M2 is connected to the open contact b and the common contact c. , The second switching contact M3 is a release contact h and a common contact e.
Is connected to.

In this state, the first battery A and the second battery B are connected in parallel, so that the vehicle load 3 is supplied with 12V power as shown by the solid arrow. At the same time, from the generator G, as indicated by the dashed arrow, the first battery A
And the second battery B is equally charged with a voltage of 12V.

Here, when the starting switch SSW is set to the closed state, the starting switch SSW, the coil of the relay R, and the backflow prevention diode D are connected from the first battery A as shown by the solid line arrow in FIG. 12 to the starter motor M via
A voltage of V is supplied, and at the same time, a voltage of 12V is supplied from the second battery B to the starting electric motor M via the second switching contact, the starting switch SSW, the coil of the relay R, and the diode D. The holding coil C2 is also supplied with a voltage of 12V. At this time, the starting electric motor M starts to rotate gently due to the supply of the voltage.

When the current flows through the coil of the relay R in this way, the contact r is closed as shown in FIG. 4, and the start switch SS is started from the first battery A and the second battery B.
A voltage of 12 V is supplied to the drive coil C1 via W, and the drive coil C1 is excited to move the push rod 1 in the arrow direction indicated by the broken line.

With the movement of the push rod 1, FIG.
, The first switching contact M2 is separated from the release contact b and the common contact c, the second switching contact M3 is separated from the release contact h and the common contact e, and the second battery B is disconnected from the circuit. From the first battery A to the drive coil C1, the holding coil C2, and the vehicle load 3.
The supply of the voltage of V is continued. The operation of a control computer (not shown in particular) which is a part of this load is also maintained.

When the push rod 1 further moves, as shown in FIG. 6, the first contact M1 is closed, the first switching contact M2 is connected to the drive contact a and the common contact d, and the second contact M2 is connected. The switching contact M3 is connected to the drive contact g and the common contact f. As a result, the first battery A and the second battery B are connected in series, and the current supply path to the starting motor M is directly from the first battery A and the second battery B via the first contact M1. And is supplied with a voltage of 24V.

On the other hand, the return spring 2 is compressed as the push rod 1 moves, and a pinion (not shown) directly connected to the starting motor M contacts the ring gear. At this time, the ring gear is in a stopped state, but since the first contact M1 and the first switching contact M2 are not in the closed state at the time when the pinion makes contact, the starter motor M
Is in a state of slowly rotating due to the current from the relay R, and when it comes into contact, it can be completely meshed by the rotation.

Further, since the first contact M1 is 24V and the starting switch SSW is 12V, the backflow prevention diode D is in a non-conducting state, and the current of the relay R disappears. As a result, the contact r is opened, but the current of the holding coil C2 causes the first contact M1.
Is kept closed.

In this way, when the main current is supplied with the pinion and the ring gear completely meshed, the internal combustion engine is in the complete explosion state, and the starting switch SSW is in the open state,
As shown in FIG. 7, the excited state of the holding coil C2 is released. By this release, the push rod 1 receives the pressing force of the return spring 2 and moves in the direction of the arrow indicated by the broken line, the first contact M1 is opened, and the first switching contact M2 is further connected to the drive contact a and the common contact d. The second switching contact M3 separates from the drive contact g and the common contact f, and disconnects the main current supply path to the starting electric motor M. At this time, the voltage of 12 V is supplied from the first battery A to the vehicle load 3, and the current is not cut off.

Further, when the push rod 1 is returned to the normal state, power is supplied from the first battery A and the second battery B to the vehicle load 3 as shown in FIG. The battery A and the second battery B are continuously charged from the generator G.

[0029]

As described above, according to the present invention, the main component of the supply voltage of the electrical equipment mounted on a large-sized vehicle is the 12V system, and 24V can be switched to and supplied to the starting motor that requires a large driving force. Therefore, there is an effect that the cost required for equipping the electric device can be significantly reduced.

Furthermore, it is possible to take out substantially the same current consumption from the batteries arranged in a divided manner, to give the same charging current from the generator, and to interrupt the power supply current to the vehicle load even when the connection of the batteries is switched. There is an effect that can be eliminated.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a state of a circuit at a normal time in the embodiment of the present invention.

FIG. 3 is a diagram showing a state of the circuit when the start switch is turned on in the embodiment of the present invention.

FIG. 4 is a diagram showing an operation start state of the engagement switch according to the embodiment of the present invention.

FIG. 5 is a diagram showing a state at the start of operation of the starting motor in the embodiment of the present invention.

FIG. 6 is a diagram showing a state in which a main current is supplied to a starting electric motor according to an embodiment of the present invention.

FIG. 7 is a diagram showing a state when the starting switch is opened in the embodiment of the present invention.

[Explanation of symbols]

 1 push rod 2 return spring 3 vehicle load A, B secondary battery (first battery and second battery) M starter motor G generator SSW starter switch ESW engagement switch C1 drive coil C2 holding coil M1 first contact M2 switch Contact M3 Second switching contact a, g Drive contact b, h Release contact c, d, e, f Common contact R Relay r Contact D Backflow prevention diode L1, L2 Load terminal

Claims (4)

[Claims] 1. A secondary battery, and a generator (G) driven by an internal combustion engine for driving a vehicle to charge the secondary battery,
A starter motor (M) for starting the internal combustion engine, a starter switch (SSW) operated by a driver, and a rotation shaft of the starter motor driven by the operation of the starter switch mechanically with the rotation shaft of the internal combustion engine as the rotation shaft. An engagement switch (ESW) including a first contact (M1) for electrically connecting the starter motor to the secondary battery and a load terminal for supplying a power supply current to an electric device equipped in the vehicle ( L1, L2), the secondary battery includes two batteries (A, B) having the same terminal voltage (12V), and the starter motor (M) has a rated voltage as described above. A voltage (24V) that is twice the terminal voltage, the generator (G) has a rated voltage equal to the terminal voltage (12V), and a first switching contact ( 2) is provided, and the two batteries (A) are connected so that the two batteries are connected in series when the engagement switch is driven and the two batteries are connected in parallel when the engagement switch is released. , B) and a connection made between the first switching contact (M2) and the generator (G) and the load terminals (L1, L2) are the first of the two batteries. A power supply circuit for an automobile, which is permanently connected to the terminal of the battery (A). 2. The connection connects the ground potential (−) side terminal of the first battery (A) of the two batteries to the ground potential, and the non-ground potential (+) side terminal. Is connected to the drive contact (a) of the first switching contact (M2), and the terminal on the ground potential (−) side of the second battery (B) of the two batteries is switched to the first switching. The common contact (c, d) of the contacts (M2) is connected, the terminal on the non-ground potential (+) side is connected to the first contact (M1), and the release contact (M2) of the first switching contact (M2) is connected. A vehicle power supply circuit according to claim 1, including a circuit for connecting b) to ground potential. 3. The engagement switch includes a drive coil (C1) and a holding coil (C2) therein, and a second switching contact (M3) interlocking with the first contact is provided, and the second switching contact is provided. Common contact (e, f) of (M3)
Is connected to the non-ground potential (+) side terminal of the first battery (A), and the drive contact (g) is connected to the ground potential (−) side terminal of the second battery (B), The release contact (h) is connected to the terminal on the non-ground potential (+) side of the second battery (B), and a relay (R) having a rated voltage equal to the terminal voltage (12V) is provided. , One end of the coil of this relay (R) is connected to the terminal on the non-ground potential (+) side of the first battery (A) via the start switch (SSW), and the coil of this relay (R) The other end is connected to the non-grounded side terminal of the starter motor (M) via a backflow prevention diode (D), and the drive coil (C1) and the holding coil (C2)
Is connected to one end of the coil of the relay, the terminal of the drive coil (C1) is connected to one end of the contact (r) of the relay (R), the other end of the contact (r) and the holding coil ( 3. The automobile power supply circuit according to claim 2, wherein the terminals of C2) are respectively connected to the ground potential. 4. The first switching contact (M2) and the second switching contact (M3) are contacts mechanically interlocking with the first contact (M1) of the engagement switch.
The power supply circuit for an automobile as described.