JP2003284256A - Charging voltage regulator for battery in vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain speedily actuating an internal combustion engine or accelerating a vehicle by driving the internal combustion engine without unnecessarily reducing the charging amount of an vehicle-mounted battery. <P>SOLUTION: The vehicle includes a generator 26 interlocked coupled to the internal combustion engine 2 for driving running, and a battery 28 connected to the generator 26 though a charging control circuit 27, and an actuating motor 29 driven by electric power for the battery 28. When the internal combustion engine 2 is determined to be less than a prescribed rotational speed and the passage of time is determined to be less than a prescribed time after the internal combustion engine 2 is actuated or accelerated, a charging voltage value from the generator 26 to the battery 28 is set to be smaller than reference charging voltage value in an ordinary case by controlling the charging control circuit 27. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to drive a generator by the power of an internal combustion engine provided for driving a vehicle so that a charging voltage is input to a battery so as to correspond to the operating state of the internal combustion engine. The present invention relates to a battery charging voltage adjusting device for a vehicle in which the value of the charging voltage for the battery is adjusted.

[0002]

2. Description of the Related Art As a charging voltage adjusting device for a battery in a vehicle as described above, there is a device disclosed in Japanese Patent Laid-Open No. 2000-253597.

According to the above publication, a vehicle is driven by an electric generator which is interlocked with an internal combustion engine for driving the vehicle, a battery which is connected to the electric generator through a charging control circuit, and the electric power of the battery. And a starting electric motor that enables the internal combustion engine to be started.

When the internal combustion engine is operated, the driving wheels of the vehicle are driven by the power output from the internal combustion engine so that the vehicle can travel. Further, the generator is driven by the power of the internal combustion engine, and a charging voltage having a predetermined value is input to the battery by the generator via the charging control circuit to perform charging. Then, electric power is output from the battery to an engine control circuit for the internal combustion engine or the like, so that the operation of the internal combustion engine can be continued.

On the other hand, when the internal combustion engine is operated so as to be started, the starter motor is driven by the electric power of the battery, and the internal combustion engine is interlocked (cranked) with the electric power, so that the internal combustion engine is started. It is designed to be used.

Further, when the vehicle is to be accelerated, the drive wheels of the vehicle are driven by the power of the internal combustion engine which is accelerated, so that the vehicle is accelerated.

By the way, when the internal combustion engine is started, the starting electric motor is driven by the electric power of the battery to start the internal combustion engine as described above. At this time, the internal combustion engine drives the generator and An attempt is made to input a charging voltage of a predetermined value from the generator to the battery.

That is, when the internal combustion engine is started, the battery outputs electric power not only to the starter motor but also to drive the generator via the internal combustion engine. However, the electric power for driving the starting electric motor tends to decrease, and therefore, it takes time to start the internal combustion engine, and there is a possibility that the internal combustion engine cannot be started quickly.

Therefore, in the above-mentioned conventional technique, when the internal combustion engine is started, the value of the charging voltage from the generator to the battery is reduced for a predetermined time after the start, so that the battery serves as a starting motor. The reduction of the electric power for driving is suppressed so that the internal combustion engine can be started quickly by the starting electric motor.

[0010]

However, when the starting electric motor is driven by the electric power of the battery as described above in order to start the internal combustion engine, for example, when the charge amount of the battery is already sufficient, When the electric power of is output to the starter motor, the internal combustion engine may reach a predetermined speed or more in a short time after the start, and in such a case, the value of the charging voltage to the battery It is not preferable to simply reduce the amount of charge for a predetermined period because it unnecessarily reduces the charge amount of the battery.

On the other hand, when the internal combustion engine is driven in an attempt to accelerate the vehicle, the internal combustion engine accelerates the drive wheels by its power. At this time, the internal combustion engine is
The generator is also accelerated to try to input a charging voltage of a predetermined value from the generator to the battery.

That is, when the internal combustion engine accelerates the vehicle, in addition to the output of the power to the vehicle, the internal combustion engine also outputs the power to the acceleration drive of the generator. Therefore, the internal combustion engine accelerates the vehicle accordingly. The motive power for driving the vehicle tends to decrease, so that it takes time to accelerate the vehicle, and this vehicle may not be accelerated quickly.

The present invention has been made in view of the above circumstances, and makes it possible to quickly start the internal combustion engine without unnecessarily reducing the charge amount of the battery mounted on the vehicle, or the internal combustion engine. An object is to make it possible to accelerate a vehicle quickly by operating an engine.

It is another object of the present invention to achieve the above-mentioned object by avoiding the inconvenience of insufficient charge amount in the battery and achieving the above-mentioned object with a simple structure.

[0015]

A charging voltage adjusting device for a battery in a vehicle according to the present invention for solving the above problems is as follows. It should be noted that the reference signs added to the respective terms in this section do not limit the technical scope of the present invention to the contents of the below-mentioned "Embodiment of the Invention".

According to the first aspect of the invention, a generator 26 interlockingly connected to the internal combustion engine 2 for driving, a battery 28 connected to the generator 26 via a charge control circuit 27, and an electric power of the battery 28. Starter motor 2 driven by
In a vehicle with 9 and

The internal combustion engine 2 is started or accelerated,
Thereafter, when it is determined that the internal combustion engine 2 is less than the predetermined number of revolutions and the elapsed time after the start or acceleration is less than the predetermined time, the charge control circuit 27 is controlled to The value of the charging voltage from the generator 26 to the battery 28 is made smaller than the value of the reference charging voltage in the normal state.

According to the invention of claim 2, in addition to the invention of claim 1, the internal combustion engine 2 is started or accelerated, and thereafter,
When it is determined that the internal combustion engine 2 is less than the predetermined rotation speed and that the elapsed time after the start or the acceleration has exceeded the predetermined time, the charge control circuit 27 is controlled and the generator is generated. The charging voltage from the battery 26 to the battery 28 is set to the reference charging voltage.

The invention of claim 3 relates to claim 1 or 2
In addition to the above invention, the engine control circuit 3 of the internal combustion engine 2
7 and the charge control circuit 27 are integrated.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a drive device for driving the vehicle which is mounted on a vehicle, and this vehicle is, for example, a motorcycle which is a saddle type vehicle.

The drive unit 1 is a four-cycle internal combustion engine 2
Is equipped with. The internal combustion engine 2 is provided with an internal combustion engine body 3. The internal combustion engine body 3 includes a crankcase 4 supported by a vehicle body, a crankshaft 5 supported by the crankcase 4, and a cylinder protruding from the crankcase 4. 6,
A piston 7 fitted in the cylinder 6 and a connecting rod 8 for interlockingly connecting the crankshaft 5 and the piston 7 are provided, and an internal space surrounded by the cylinder 6 and the piston 7 serves as a combustion chamber 9. Has been done.

The internal combustion engine 2 has an intake passage 12 for communicating the outside of the internal combustion engine body 3 with the combustion chamber 9 of the internal combustion engine body 3, and the opening (throttle opening) of the intake passage 12 is adjustable. And a fuel supply means 15 for supplying fuel 14 to the combustion chamber 9 of the internal combustion engine body 3 through the intake passage 12 and the fuel supply means 1
Reference numeral 5 denotes a solenoid open / close type fuel injection valve 17 capable of injecting fuel 14 into the intake passage 12, and the fuel injection valve 1
7 is provided with a fuel pump 19 that pressurizes and supplies the fuel 14 in the fuel tank 18. Further, an exhaust passage 21 is provided for communicating the combustion chamber 9 with the outside of the internal combustion engine body 3.

In the internal combustion engine 2, the discharge part is the combustion chamber 9
And an ignition coil 24 electrically connected to the ignition plug 23.

A generator 26, which is a flywheel magneto that is interlocked with the crankshaft 5 of the internal combustion engine 2, a battery 28 connected to the generator 26 via a charge control circuit 27, and an internal combustion engine of the internal combustion engine 2. A starter motor 29 is provided which is linked to the engine body 3 and is electrically connected to the battery 28 and driven by the electric power of the battery 28.

A crank angle detection sensor 32 for detecting the crank angle θ of the crankshaft 5 of the internal combustion engine body 3 and a rotation speed for detecting the rotation speed of the crankshaft 5 of the internal combustion engine body 3 (the rotation speed of the internal combustion engine 2). A detection sensor 33, a throttle opening detection sensor 34 for detecting the opening of the throttle valve 13 (throttle opening), and an intake pressure (intake negative pressure) in the intake passage 12 downstream of the throttle valve 13. The intake pressure detection sensor 35 is electrically connected to the fuel injection valve 17, the ignition coil 24, the generator 26, the charge control circuit 27, the battery 28, the starter motor 29, and the sensors 32 to 35, and the internal combustion engine An engine control circuit 37 for electronically controlling the engine 2 is provided.

During operation of the internal combustion engine 2, the air 39 on the atmosphere side is taken in the intake stroke of the internal combustion engine body 3 of the internal combustion engine 2.
Is sucked into the combustion chamber 9 through the intake passage 12. At this time, the fuel 14 is supplied to the combustion chamber 9 by the fuel supply means 15, the combustion chamber 9 and the air 39 are mixed, and after the compression stroke, the fuel 14 is used for combustion in the explosion stroke. The combustion gas generated by the combustion in the combustion chamber 9 of the internal combustion engine body 3 is discharged to the outside of the internal combustion engine body 3 through the exhaust passage 21 as the exhaust gas 40 in the exhaust stroke.

With the combustion in the combustion chamber 9, the internal combustion engine body 3 of the internal combustion engine 2 outputs power to the drive wheels for traveling of the vehicle so that the vehicle can travel. Further, the power of the internal combustion engine 2 drives the generator 26, and the generator 26 inputs a charging voltage of a predetermined value to the battery 28 via the charging control circuit 27 to charge the battery 28.
Further, electric power is output from the battery 28 to the ignition coil 24, the charging control circuit 27, the sensors 32 to 35, the engine control circuit 37, etc., so that the operation of the internal combustion engine 2 can be continued.

On the other hand, when the internal combustion engine 2 is operated to start, the electric power of the battery 28 drives the starter motor 29, and the crankshaft 5 of the internal combustion engine body 3 of the internal combustion engine 2 is interlocked with the electric power. The internal combustion engine 2 is started.

When the vehicle is to be accelerated, the throttle valve 13 is operated to increase the throttle opening, and accordingly, the amount of fuel 14 injected by the fuel injection valve 17 of the fuel supply means 15 is increased. Is increased, the internal combustion engine 2 is accelerated, and the drive wheels of the vehicle are driven by the power of the internal combustion engine 2, and thus the vehicle is accelerated.

The operation of the internal combustion engine 2 will be described in more detail with reference to FIGS.

FIG. 2 shows a flow chart for the engine control circuit 37, and S1 to 11 show the steps of the program.

First, in S1, when the internal combustion engine 2 is started, the flag is set to 0 at the start of this start. Here, the determination that the internal combustion engine 2 has been started is made by detecting the operation of the starting electric motor 29.

After starting the internal combustion engine 2, in S2, the internal combustion engine 2 has a predetermined rotational speed (for example, 1000 rpm) based on the detection signal of the rotational speed detection sensor 33.
r. p. m) or more, that is, when it is determined that the internal combustion engine 2 is in a normal operation state in which the internal combustion engine 2 is quickly started, it is determined that the starting operation is completed, and the flag is set to 1 after the start. (S3), and the charge control circuit 27 is controlled so that the battery 26 is transferred from the generator 26.
Is the value of the standard charging voltage during normal operation (14.
5V) (S4), and thereafter, the process returns to S1 and the operating state of the internal combustion engine 2 is continued.

On the other hand, when the internal combustion engine 2 is determined to be less than the predetermined rotational speed based on the detection signal of the rotational speed detection sensor 33 in S2 after the start of the internal combustion engine 2 is started, S5 is executed. Is executed. This S5
When it is determined that the elapsed time from the start of the start is less than a predetermined time (for example, 5 seconds),
The charging control circuit 27 is controlled so that the value of the charging voltage from the generator 26 to the battery 28 is smaller than the value of the standard charging voltage (14.5V) in the normal state (12.
5V).

That is, the control by the engine control circuit 37 is determined to be an abnormal operating state in which the internal combustion engine 2 is not started quickly, and in this case, the generator 26 is operated. The charging current from the battery to the battery 28 is reduced.

Then, as described above, the charging control circuit 27 is added to the battery 28 by the amount that the value of the charging voltage is reduced.
The load on the generator 26 that is driven to input the charging voltage via the
The burden on the internal combustion engine 2 that outputs power to drive the engine is small and sufficient.

Therefore, since the power output by the internal combustion engine 2 is small by that much, the internal combustion engine 2 can be started more quickly.

On the other hand, in S5, the internal combustion engine 2
When it is determined that the elapsed time after the start of the engine has passed the predetermined time (more than the predetermined time), the charging voltage is set to the value of the normal reference charging voltage (14.5V).

That is, the control by the engine control circuit 37 is determined to be in a heavy and abnormal operating state because it takes too long to start the internal combustion engine 2.
Thus, when the internal combustion engine 2 takes too long to start, if the charging voltage is kept at a small value (12.5 V) for a long time, the charge amount of the battery 28 may be insufficient. Occurs. When the battery 28 has a shortage of charge in this way, the engine control circuit 37 may not operate and the operating state of the internal combustion engine 2 may not be continued in a short time.

Therefore, as described above, when it takes too long to start the internal combustion engine 2, the generator 26 is used.
Rather than reducing the power of the internal combustion engine 2 that is trying to drive the engine, the battery 28 is charged with a predetermined charge amount by giving priority to setting the charge voltage to a normal value (14.5 V). I'm trying to secure it.

Therefore, even if it takes time to start the internal combustion engine 2, the operating state of the internal combustion engine 2 can be continued for a long time, which is preferable for traveling of the vehicle.

In S1, the post-start flag is set to 1 when the internal combustion engine 2 is in the operating state in which the start is completed,
S7 is executed.

If it is determined in S7 that the internal combustion engine 2 is not accelerated, the acceleration state flag is set to 0,
Return to S1. Here, whether or not the internal combustion engine 2 has been accelerated is determined as shown in FIG. 3 based on the detection signals of the sensors 32 to 35, which will be described later.

If it is determined in S7 that the vehicle has been accelerated,
The acceleration state flag is set to 1, and S8 is executed.

After it is judged that the internal combustion engine 2 is accelerated (acceleration is detected), the internal combustion engine 2 is rotated at a predetermined rotational speed (for example, based on the detection signal of the rotational speed detection sensor 33 in S8). 5,000 rpm) or more, that is, when it is determined that the internal combustion engine 2 is in a normal operating state in which the acceleration is performed quickly, it is assumed that the acceleration operation is completed and the acceleration state is completed. The flag is set to 0 (S9), and the charging control circuit 27 is controlled to set the value of the charging voltage from the generator 26 to the battery 28 to the value of the standard charging voltage at the normal time (14.5V) ( S10), then, returning to S1, the operation of the internal combustion engine 2 is continued.

On the other hand, after it is determined that the internal combustion engine 2 is accelerated, when it is determined in S8 that the internal combustion engine 2 is less than the predetermined rotational speed based on the detection signal of the rotational speed detection sensor 33. , S11 is executed.
In S11, when it is determined that the elapsed time after the acceleration is determined is less than the predetermined time (for example, 5 seconds), the charging control circuit 27 is controlled to allow the generator 26 to operate the battery. The value of the charging voltage to 28 is set to the value of the charging voltage (12.5V) which is smaller than the value of the standard charging voltage (14.5V) at the normal time.

That is, the control by the engine control circuit 37 is determined to be an abnormal operating state in which the internal combustion engine 2 is not accelerated quickly. In this case, the generator 26 is operated. The charging current from the battery to the battery 28 is reduced.

Then, as described above, the charging control circuit 27 is added to the battery 28 by the amount that the value of the charging voltage is reduced.
The load on the generator 26 that is driven to input the charging voltage via the
The burden on the internal combustion engine 2 that outputs power to drive the engine is small and sufficient.

Therefore, since the power output from the internal combustion engine 2 is small by that amount, the internal combustion engine 2 can be accelerated more quickly.

On the other hand, when it is determined in S11 that the elapsed time after it is determined that the internal combustion engine 2 is accelerated has passed the predetermined time (more than the predetermined time), the charging voltage is normally set. Reference charging voltage value (1
4.5V).

That is, in the control by the engine control circuit 37, it is determined that the internal combustion engine 2 takes too much time to accelerate and is in a heavy and abnormal operating state.
In this way, when the internal combustion engine 2 takes too long to accelerate, if the charging voltage is kept at a small value (12.5 V) for a long time, the charge amount of the battery 28 may be insufficient. Occurs. When the battery 28 is thus insufficiently charged, the engine control circuit 37 may not operate and the operating state of the internal combustion engine 2 may not be continued in a short time.

Therefore, as described above, when it takes too long to accelerate the internal combustion engine 2, the generator 26 is used.
Rather than reducing the power of the internal combustion engine 2 that is trying to drive the engine, the battery 28 is charged with a predetermined charge amount by giving priority to setting the charge voltage to a normal value (14.5 V). I'm trying to secure it.

Therefore, even if it takes time to accelerate the internal combustion engine 2, the operating state of the internal combustion engine 2 can be continued for a long time, which is preferable for traveling of the vehicle.

In FIG. 3, each of the sensors 32 to 35 described above is used.
The engine control circuit 37 determines the injection timing and the injection period (injection amount) of the fuel 14 of the fuel injection valve 17 based on the detection signal.

That is, the fuel 14 generated by the fuel injection valve 17 is
The timing of the injection A is approximately the same crank angle θ at the transition timing from the compression stroke to the intake stroke of the internal combustion engine 2,
Each injection A is performed, and the period T of the injection A, that is, the injection amount is controlled as follows. That is, the internal combustion engine 2
Transition period from the compression stroke to the explosion stroke (same stroke)
At substantially the same crank angle θ1, the period T of the injection A of the fuel 14 is determined in accordance with the magnitude of the intake negative pressure P detected by the intake pressure detection sensor 35. P6 corresponds to each of A1 to A6.

More specifically, the intake negative pressure P is P1,
A large value like P2 (or a small value like P3 to P6) means that the throttle opening detection sensor 34
The throttle opening detected by is closed (or open)
It means that a small (or large) power output is required, and therefore the period T of the injection A of the fuel 14 is the same as the period T1 of the injections A1 and A2. , Shorter (or injection A
It is made longer than the period T2 in 3 to A6).

Further, whether or not the internal combustion engine 2 is accelerated as described in S7 of FIG. 2 is determined as follows.

That is, the intake negative pressures P are detected by the intake pressure detection sensors 35 at substantially the same crank angles θ2 at the transition timings (the same strokes) from the exhaust stroke to the intake stroke, and they are temporally adjacent to each other. When the difference ΔP = P8−P7 between the intake negative pressures P7 and P8 exceeds a predetermined set value, it is determined that the internal combustion engine 2 has been accelerated.

As shown by the chain double-dashed line in FIG. 1, the charge control circuit 27 and the engine control circuit 37 are installed on one printed circuit board and integrated with each other (modularization).
Has been done.

For this reason, the number of parts of the internal combustion engine 2 is reduced, the structure is simplified, and the wiring work between the charging control circuit 27 and the engine control circuit 37 is simplified. Assembly work becomes easy.

Although the above is based on the illustrated example, the predetermined time of the elapsed time after it is judged that the internal combustion engine 2 is less than the predetermined rotation speed and after the start of the start or the acceleration is judged. When the determination is made and the charging voltage value is controlled to be large or small, the timings of the both determinations are substantially the same, but either may be earlier.

The determination as to whether or not the internal combustion engine 2 has been started may be based on the detection signals of the vehicle speed, the crank angle detection sensor 32, and the throttle opening detection sensor 34.

The determination as to whether or not the internal combustion engine 2 has been accelerated may be based on the change over time of the throttle opening based on the detection signal of the throttle opening detection sensor 34.

[0065]

The effects of the present invention are as follows.

According to a first aspect of the present invention, a generator that is interlocked with an internal combustion engine for driving the vehicle, a battery that is connected to the generator through a charging control circuit, and a starter motor that is driven by the power of the battery. In a vehicle equipped with

When the internal combustion engine is started or accelerated, and thereafter it is determined that the internal combustion engine is less than a predetermined number of revolutions, and the elapsed time after the start or acceleration is less than a predetermined time. The charging control circuit is controlled so that the value of the charging voltage from the generator to the battery becomes smaller than the value of the reference charging voltage in the normal state.

That is, the above-mentioned control is judged to be an abnormal operating state in which the internal combustion engine is not started or accelerated quickly. In this case, the generator transfers to the battery. The value of the charging current is made smaller.

As described above, since the value of the charging voltage is reduced, the load on the generator that drives the battery to input the charging voltage via the charging control circuit is lightened. The burden on the internal combustion engine that outputs power to drive the generator is small.

Therefore, since the power output from the internal combustion engine is small by that much, starting of the internal combustion engine
Or it will be accelerated more quickly.

Further, according to the above invention, when the internal combustion engine reaches a predetermined speed or more after being started or accelerated, even if the elapsed time is less than the predetermined time, The charging voltage can be immediately changed from a small value charging voltage to a large value reference charging voltage.

Therefore, it is prevented that the charge amount of the battery is unnecessarily reduced by keeping the value of the charging voltage unnecessarily small.

According to a second aspect of the present invention, the internal combustion engine is started or accelerated, and thereafter, it is determined that the internal combustion engine is less than a predetermined rotation speed, and the elapsed time after the start or acceleration is a predetermined time. When it is determined that the time has elapsed, the charging control circuit is controlled so that the charging voltage from the generator to the battery becomes the reference charging voltage.

That is, in the above control, it is determined that the internal combustion engine is starting up or accelerating too much, and it is determined that the operating state is heavier and abnormal. Alternatively, when the acceleration takes too long, if the charging voltage is kept at a low value for the long time, the charge amount of the battery may become insufficient. Then, if the battery is insufficiently charged, the operating state of the internal combustion engine may not be continued in a short time.

Therefore, as described above, when it takes too long to start or accelerate the internal combustion engine,
Rather than reducing the power of the internal combustion engine that outputs to drive the generator, priority is given to setting the charging voltage to a normal value to ensure that the battery has a predetermined charge amount. There is.

Therefore, even if it takes time to start or accelerate the internal combustion engine, the operating state of the internal combustion engine can be continued for a long time, which is preferable for traveling of the vehicle.

According to a third aspect of the present invention, the engine control circuit of the internal combustion engine and the charge control circuit are integrated.

For this reason, the number of parts of the internal combustion engine is reduced, the structure is simplified, and the wiring work between the charging control circuit and the engine control circuit is simplified, so that the internal combustion engine is easily assembled. Becomes

[Brief description of drawings]

FIG. 1 is an overall diagram.

FIG. 2 is a flowchart of an engine control circuit.

FIG. 3 is a graph showing an operating state of the internal combustion engine.

[Explanation of symbols]

1 drive 2 Internal combustion engine 3 Internal combustion engine body 9 Combustion chamber 12 Intake passage 13 Throttle valve 14 Fuel 15 Fuel supply means 17 Fuel injection valve 23 Spark plug 26 generator 27 Charge control circuit 28 battery 29 Starter motor 32 Crank angle detection sensor 33 RPM sensor 34 Throttle opening detection sensor 35 Intake pressure detection sensor 37 Engine control circuit 39 air 40 exhaust

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Motoaki Mizushima             Yamaha Motor, 2500 Shinkai, Iwata, Shizuoka Prefecture             Within the corporation (72) Inventor Yuichiro Sawada             Yamaha Motor, 2500 Shinkai, Iwata, Shizuoka Prefecture             Within the corporation F-term (reference) 3G093 BA02 BA05 CA01 DA01 DA03                       DA06 DA07 DB26 EB09 EC02                       FA11 FB02 FB05                 5G060 AA04 CA13 CA16 DB07                 5H590 AA01 AB05 CA07 CA23 CC02                       CC18 CE05 EA01 EA07 EA13                       EB12 EB14 FA01 HA02 HA15                       HA25 HA27

Claims (3)

[Claims] 1. A vehicle including a generator that is interlocked with an internal combustion engine for driving a vehicle, a battery that is connected to the generator through a charge control circuit, and a starter motor that is driven by the electric power of the battery. In, the internal combustion engine is started or accelerated, then, it is determined that the internal combustion engine is less than a predetermined rotation speed, and, when it is determined that the elapsed time after the start or after acceleration is less than a predetermined time, A charging voltage adjusting device for a battery in a vehicle, wherein the charging control circuit is controlled so that a value of a charging voltage from the generator to the battery becomes smaller than a value of a reference charging voltage in a normal time. 2. The internal combustion engine is started or accelerated,
After that, when it is determined that the internal combustion engine is less than a predetermined rotation speed, and when the elapsed time after the start or acceleration has reached a predetermined time, the charge control circuit is controlled to control the generator. The charging voltage adjusting device for a battery in a vehicle according to claim 1, wherein the charging voltage from the battery to the battery is set to the reference charging voltage. 3. The charging voltage adjusting device for a battery in a vehicle according to claim 1, wherein the engine control circuit of the internal combustion engine and the charging control circuit are integrated.