JPH09140196A - Power generation controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fuel consumption by controlling the switching of generating current or exciting current of a generator in synchronism with the change of stroke of an internal combustion engine and suppressing fluctuation in the r.p.m. of engine thereby preventing the engine r.p.m. from increasing and lowering the idle r.p.m. SOLUTION: When the engine r.p.m. is higher than the idle r.p.m. and the battery voltage is low (power generation is requested), power generation is controlled such that the battery voltage matches a target level which is specified times as high as a reference voltage Vref. When the engine r.p.m. is lower than the idle r.p.m., power generation is inhibited even if a power generation request (Hi level) is outputted from a comparator 341 during a compression stroke of 180-360 deg. crank interval from a moment of ignition (ti). Consequently, the engine load is reduced in the compression stroke and fluctuation is suppressed in torque and speed. According to the controller, fuel consumption can be improved by lowering the idle r.p.m. while avoiding engine stall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power generation control device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 4-143430 proposes a vehicular power generation control device for reducing idle speed and improving fuel consumption when the load of the generator is small.

[0003]

However, when the number of cylinders is small, such as in a single-cylinder internal combustion engine for two-wheeled vehicles, there are many adverse effects such as an increase in fluctuations in the engine speed and the tendency for engine stall to occur. Therefore, it has been difficult to improve fuel efficiency by reducing the idle speed.

The present invention has been made in view of the above problems, and a solution thereof is to provide a vehicular power generation control device capable of improving fuel consumption by reducing idle rotation speed while suppressing increase in fluctuation of engine rotation speed. It should be an issue.

[0005]

According to the first aspect of the present invention, in the operating state at an idling speed or lower, the generated current or exciting current of the generator is intermittently controlled in synchronization with the stroke change of the internal combustion engine. Since the control for reducing the change in the engine speed (hereinafter, also referred to as stroke synchronous power generation output control) is performed,
Even if the set value of the idle speed is reduced by that amount, engine stall or the like is less likely to occur, and as a result, fuel consumption can be saved by reducing the idle speed.

Preferably, when the engine speed exceeds the idle speed, the stroke synchronous power generation output control is stopped. By doing this, the maximum power generation output in other rotation speed regions that do not exhibit the effect of improving fuel efficiency while avoiding engine stall is increased, so that it is possible to supply power to a large electric load and prevent a shortage of battery capacity. You can According to the means of claim 2, in the means of claim 1, in particular, since the generated current or the exciting current (particularly its average value) during the compression stroke period is reduced from that during the other stroke period, the compression stroke period is reduced. The engine load can be reduced, and as a result, fluctuations in the load torque of the engine as a whole can be reduced to reduce changes in engine speed, and engine stalls can be avoided while reducing fuel consumption by reducing idle speed. can do.

According to the means of claim 3, the above-mentioned claim 1
In the described means, in particular, since the generated current or the exciting current (particularly its average value) during the explosion stroke is increased more than that during the other strokes, the engine load during the explosion stroke can be increased, and as a result, It is possible to reduce fluctuations in the output torque (generated torque-load torque) of the engine as a whole to reduce changes in the engine speed, avoid engine stalls, and reduce fuel consumption by reducing idle speed.

According to the means of claim 4, said claim 1
In the described means, in particular, since the power generation period of the predetermined phase period width is set before and after the torque peak time of the fundamental frequency component of the torque fluctuation, the engine load in the period near the peak of the main stroke synchronization fluctuation component of the engine speed is selected. The basic frequency component, which is the main component of the output torque fluctuation of the engine, can be reduced to further improve the above effect.

According to the means of claim 5, said claim 1
Particularly in the means described, since the power generation stop period of the predetermined phase period width is set before and after the torque bottom time point of the fundamental frequency component of the torque fluctuation, the engine load in the bottom vicinity period of the main stroke synchronization fluctuation component of the engine speed is set. It is possible to selectively reduce the fundamental frequency component, which is a main component of the output torque fluctuation of the engine, to further improve the above effect.

According to the means of claim 6, the above-mentioned claim 4
Alternatively, in the means described in 5, the power generation period or the power generation stop period is set according to the target power generation rate of the generator, so that it is possible to generate power with an appropriate amount of power generation while suppressing fluctuations in the engine speed. . That is, since the power is generated near the peak time of the fundamental frequency component of the torque fluctuation of the engine, the fundamental frequency component of the torque fluctuation can be satisfactorily reduced. Alternatively, since the power generation is stopped near the bottom time point of the fundamental frequency component of the torque fluctuation of the engine, the fundamental frequency component of the torque fluctuation can be satisfactorily reduced.

According to the means of claim 7, the above-mentioned claim 6
Particularly in the described means, since the power generation period or the power generation stop period is determined based on the voltage difference between the battery voltage and the predetermined reference voltage, it is possible to prevent overcharging and overdischarging of the battery while avoiding the engine rotation speed synchronized with the stroke. Fluctuations can be suppressed. According to the means of claim 8, in the means of claim 1, in particular, the timing of the stroke synchronous power generation output control is determined by using the internal signal or the output signal of the ignition device of the internal combustion engine, so that it is expensive and complicated. The installation cost and installation space of the rotation angle sensor having various configurations can be saved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described with reference to the following examples.

[0013]

【Example】

(Embodiment 1) FIG. 1 shows an embodiment of a vehicular power generation device using the vehicular power generation control device of the present invention. (Structure) This vehicular generator comprises a vehicular generator 2 and a regulator 3, and supplies power to a battery 4 and a vehicular electric load (not shown). An engine (not shown) ignition device 5 outputs an ignition pulse voltage Ip to the engine and outputs a rotation angle signal to the regulator 3.

The vehicle generator 2 is a well-known three-phase synchronous generator having a stator around which a three-phase armature winding 20 is wound and a rotor around which a field winding 21 is wound. Phase full wave rectifier 2
2 built-in. The high level DC end of the three-phase full-wave rectifier 22 is connected to the high level end of the battery 4, and the low level ends thereof are grounded. The regulator 3 includes a power supply circuit 31, a reference voltage generation circuit 32, a resistance voltage dividing circuit 33, and a comparator 34.
1, 342, switching transistor 35, inverter 36, mono-multivibrator 37, integrating circuit 38,
It has a logic gate circuit 39, a flyback diode D, and a base current limiting resistor rb. The power supply circuit 31 converts the battery voltage input through the ignition switch 1 into a predetermined DC constant voltage, and a comparator 341,
It is supplied to the 342 and the logic gate circuit 39 as a power supply voltage.

The reference voltage generating circuit 32 comprises a series circuit of a resistor r1 and a Zener diode ZD, and supplies the reference voltage Vref to the + input terminals of the comparators 341 and 342 from the connection point. The resistance voltage dividing circuit 33 is a voltage dividing circuit in which the resistance r1 and the resistance r2 are connected in series, and applies the voltage division Vb of the battery voltage to the negative input terminal of the comparator 341.

The comparator 341 has a reference voltage Vref.
And the partial voltage Vb of the battery voltage are compared, and the reference voltage Vr
If ef is high, Hi is output, and if ef is low, Lo is output. The inverter 36 is an inverting buffer circuit, which inverts and amplifies the pulse voltage Vtr2 as the rotation angle signal received from the ignition device 5 and outputs the pulse voltage Vtr2 to the AND circuit 391 of the logic gate circuit 39.

The mono-multivibrator 37 receives a pulse voltage Vtr as a rotation angle signal received from the ignition device 5.
A pulse voltage Vp that becomes Hi is output for a certain period of time from the falling edge of 2 and this pulse voltage Vp is converted into a direct current by the integrating circuit 38 and the reference voltage Vp is output by the comparator 342.
compared with ref. The integrating circuit 38 is composed of a first-stage integrating circuit unit including a resistor r4 and a capacitor C1 and a second-stage integrating circuit unit including a resistor r5 and a capacitor C2, and integrates the input voltage.

The logic gate circuit 39 is an AND gate 39.
1, 392 and an OR circuit 393, the switching voltage of the switching transistor 35 is controlled by its output voltage.
An exciting current is passed through the field winding 21 at a power generation rate determined by the intermittent control of the switching transistor 35,
As a result, the three-phase AC output generated in the three-phase armature winding 20 is rectified by the three-phase full-wave rectifier 22 and supplied to the battery 4 and the vehicle electric load (not shown).

The ignition device 5 will be described with reference to FIGS. 2 and 3. The ignition device 5 is an ordinary electromagnetic power generation type full transistor type ignition device, and the signal voltage (rotation angle signal) Vs output from the signal generator 41 is required at the ignition timing ti through the transistors Tr1, Tr2, Tr3, Tr4. The pulse voltage is shaped into a pulse voltage, and is output from the ignition transformer 42 as an ignition pulse Ip. The ignition pulse Ip is distributed to each cylinder through a distributor in the multi-cylinder period, but in the present embodiment, since a single cylinder (two-cycle) engine is adopted, it is directly supplied to an ignition plug (not shown). . Since the signal generator 41 itself has a well-known configuration, its detailed description is omitted.

In the ignition device 5 thus constructed, the signal voltage (rotation angle signal) V is applied to its coil by the rotation of the rotor of the signal generator 41 synchronized with the crankshaft.
s occurs, and based on this signal voltage (rotation angle signal) Vs, the transistor Tr1 supplies the pulse voltage Vtr1, the transistor Tr2 supplies the pulse voltage Vtr2, and the transistor Tr2.
3 outputs the pulse voltage Vtr3, and the transistor Tr4 outputs the pulse voltage Vtr4.

In this embodiment, the ignition device is adopted as the rotation angle detecting means in the present invention for the sake of simplification of the construction, but it is connected to the crankshaft to detect its phase angle (so-called crank angle). It is of course possible to install a rotary encoder or crank angle sensor. Next, the power generation control operation of this embodiment will be described.

Since the mono-multivibrator 37 outputs a pulse voltage Vp having a constant width at each ignition timing,
The DC signal voltage Vdc output from the integrating circuit 38 is proportional to the number of pulse voltages Vp input per constant time, that is, the engine speed. Since the circuit parameters are set so that the reference voltage Vref becomes the value of the DC signal voltage Vdc at the idle speed, the comparator 3
42 outputs Lo when the engine speed exceeds the idle speed.

The pulse voltage Vt output from the ignition device 5
As shown in FIG. 3, r2 outputs Lo for a period of approximately 180 degrees of crank angle from the ignition timing Ti, and outputs Hi for a subsequent period of 180 degrees of crank angle.
Indicates a crank angle of approximately 180 degrees from the ignition timing Ti, that is, since this engine is a 2-cycle single-cylinder engine, it outputs Hi in the combustion stroke and Lo in the subsequent compression stroke. The comparator 341 outputs Hi when the divided voltage Vb of the battery voltage is smaller than the reference voltage Vref, and outputs Lo when it is larger.

Therefore, when the engine speed is higher than the idle speed and the battery voltage is low (when there is a power generation request), the AND gate 391 becomes Lo and the AND gate 392 becomes the OR gate 393 and the base current limit. Power is supplied to the switching transistor 35 through the resistor rb to turn it on, and as a result, during non-idling, power generation control is performed so that the battery voltage matches a target voltage that is a constant multiple of the reference voltage Vref as usual.

Next, when the engine speed is lower than the idle speed, the comparator 342 outputs Hi, and the AND gate 392 outputs Lo, and the AND gate 391 outputs the state where the comparator 341 is Hi ( In the case where the battery voltage is relatively small), based on the output of the inverter 36, as described above, the ignition timing ti becomes Hi for 180 degrees in the crank period, the switching transistor 35 is turned on, and power generation is performed.

Conversely speaking, in this embodiment, the ignition timing ti is set.
During the compression stroke period of 180 to 360 degrees in the crank period from 1 to 3, even if the power generation request (Hi level) is output from the comparator 341, the power generation is prohibited. As a result, the engine load is reduced during the compression stroke period, and torque fluctuations and speed fluctuations are reduced. Therefore, it is possible to avoid the engine stall and reduce the idle speed to improve the fuel consumption.

As described above, if the power generation request (Hi level) is output from the comparator 341, if power generation is not performed during the compression stroke period, the combustion period is naturally stronger (for a longer period) in the next combustion period. It can be considered that the power generation request is sustained, and eventually the power generation period is shifted to the combustion stroke period side, which is a preferable result in terms of reducing torque fluctuation. The rising of the exciting current flowing through the switching transistor 35 is determined by the field winding 21.
As shown in FIG. 3, the exciting current flowing through the field winding 21 flows due to the presence of the flyback diode D even after the switching transistor 35 is turned off. Is delayed by a predetermined phase angle from the ON period of the switching transistor, but this is not an essential problem in achieving the effects of the above-described embodiment.

(Embodiment 2) Another embodiment will be described with reference to FIG. FIG. 4 shows the regulator 3a in FIG.
The difference is that the microcomputer 30, the switching transistor 35, and the flyback diode D are replaced. Further, in this embodiment, the fluctuation of the output torque of the engine and the fluctuation of the engine speed as its integrated value are even larger.
A cycle single cylinder gasoline engine will be described as an example.

The waveform of the engine torque Te of this 4-cycle single cylinder engine is shown in FIG. The engine torque peaks at the beginning of the explosion stroke period, the negative torque becomes relatively small during the scavenging stroke period and the intake stroke period thereafter, and becomes considerably large negative torque at the end of the next compression stroke period. That is, the engine torque Te is separated into a long-term negative torque and a relatively short-term positive torque. Then, the integrated value of the torque for one cycle becomes the releasable engine torque, and the value obtained by subtracting the generator load torque from this releasable engine torque is the output torque in this embodiment.

Hereinafter, the fundamental frequency component Tef of the fluctuation of the engine torque Te will be analyzed. The fundamental frequency component Tef of the fluctuation of the engine torque Te can be considered as a vector sum of the above-described time centroid ta of the positive torque component and its magnitude Ta, and the above-described time centroid tb of the negative torque component and its magnitude Tb. Yes (see FIGS. 5 and 6).

After all, the fundamental frequency component Tef of the fluctuation of the engine torque Te becomes the above-mentioned combined vector, and the torque peak is advanced from the positive torque component by the phase angle θ '(advanced by the phase angle θ1 from the ignition timing ti). It has a sinusoidal waveform with a time point tp. Since Ta and Tb change due to changes in the throttle opening, etc., the torque peak time tp changes when the accelerator is stepped. However, in this embodiment, the ignition time ti changes regardless of the change in the rotational speed and the accelerator opening. Phase angle θ at the torque peak time tp
1 is assumed to be constant. The variation itself of the phase angle θ1 can be stored in the ROM in advance and corrected.

As described above, the engine torque T is advanced by a certain phase angle (crank angle) θ1 from the ignition timing.
torque peak point tp of fundamental frequency component Tef of fluctuation of e
It turns out that can be considered to exist. That means
If the power generation period ΔT is set around this torque peak point tp, the fundamental frequency component Tef of the fluctuation of the engine torque Te can be reduced most preferably.
Then, as shown in T1 to T4 of FIG. 5, the power generation period ΔT
It can be understood that the optimum charging of the battery can be performed while the fundamental frequency component Tef of the fluctuation of the engine torque Te is satisfactorily reduced if is adjusted according to the power generation request (power generation load). The power generation request (power generation load) is a so-called target power generation rate (target duty ratio), and in this embodiment, the power generation request (power generation load) depends on the difference between the battery voltage and the reference voltage.
Is determined.

For example, in FIG. 5, the power generation period ΔT is extended from T1 to T4 as the battery voltage decreases. The actual power generation control thereafter when the power generation period ΔT is determined will be described with reference to FIG. 7. The start time of the determined power generation period ΔT is ts, and the end time thereof is te.
At this ts, the switching transistor 35 is turned on,
When turned off at te, the exciting currents If1 and If2 have the waveforms shown in FIG. 7 due to the effect of the impedance of the field winding 21. When the combined excitation current If, which is the sum of the excitation currents If1 and If2, is replaced with the rectangular wave Ps, it can be considered that the power generation period ΔT is delayed by a certain time ΔTd, as shown in FIG. 7. Therefore, from the start time Ts of the power generation period ΔT to ΔT
It can be seen that if the power generation period is set earlier by d, the fundamental frequency component Tef of the fluctuation of the engine torque Te can be reduced most preferably.

The power generation control will be described with reference to FIG.
First, the key switch 1 is turned on and the initial setting is performed (S
100), the pulse voltage Vtr2 is input from the ignition device 5 (S102), the width of the input pulse voltage Vtr2 is counted, and the cycle period (1 crank angle 360 degrees) is calculated (S104).

Next, it is checked whether the engine speed, which is the reciprocal of the cycle period, is equal to or less than a predetermined idle speed stored in advance (S106), and if not, S102.
If not, the battery voltage is read (S108), and the difference voltage ΔV = Vb−V between the read battery voltage division voltage Vb and the reference voltage Vref stored in advance.
Calculate ref. Then, the target power generation rate (target duty ratio) corresponding to the calculated difference voltage ΔV is searched from the map (S110). For example, the difference voltage ΔV is +0.5
If it is V, the target power generation rate is 0% assuming that the battery is sufficiently charged, and if the differential voltage ΔV is + 0V, the target power generation rate is 40% assuming that the battery is appropriately charged, and the differential voltage ΔV is − If it is 0.5 V, the target power generation rate is set to 80% because the capacity is significantly insufficient.

Incidentally, based on the throttle opening and the engine speed, the torque peak time tp and the ignition time t of the fundamental frequency component Tef of the fluctuation of the engine torque Te are shown in the map.
You may make it search the delay phase angle from i.
However, in this embodiment, the delay phase angle is constant in order to simplify the control configuration. Next, calculate the power generation period by multiplying the read duty ratio by the cycle period,
Torque peak time point tp for each half of the obtained power generation period
Power generation start time ts and power generation end time t
Determine e. Next, the corrected power generation period (from ts 'to te') is determined by advancing the power generation start time point ts and the power generation end time point te by the delay time ΔTd (S1).
12), based on which the switching transistor 35
Intermittently.

In this way, it is possible to favorably suppress fluctuations in the engine speed in the low speed range below the idle speed. (Embodiment 3) Another embodiment will be described with reference to FIG. In this embodiment, in the power generation control operation of the second embodiment shown in FIG. 8, it is checked whether or not the state in which the target power generation rate is maintained at the highest level continues for a predetermined time or more (S116), and if so, the ECU (engine control (Device) to instruct not to increase the idle speed (S118), otherwise ECU
The engine control device is instructed to increase the idle speed to increase the power generation output (S120), thereby avoiding the shortage of the capacity of the battery 4.

In this way, although the above-mentioned power generation stop period is set to suppress the fluctuation of the engine speed, the generated voltage is increased and the generated current is increased by the increase of the idle speed when the electric load is large. It is possible to cope with the increase in the power generation load. (Embodiment 4) Another embodiment will be described with reference to FIG.

This embodiment employs an AC generator (hereinafter referred to as a magnet generator) having a magnet field type rotor as the generator 2a in the vehicular power generator of the first embodiment, and the switching in the above embodiment is performed. Instead of the exciting current intermittent control by the transistor 35, the generated current intermittent control by the transfer switch 350 is performed. The transfer switch 350 connects the high-order DC output end of the three-phase full-wave rectifier 22 and the high-end end of the battery 4. Although the transfer switch 350 uses an inexpensive npn bipolar transistor, it may be an n-channel MOS transistor. The characteristics of this transfer switch 350 are:
It is at the point where its emitter (or source) is connected to the battery 4.

The regulator 3a has almost the same configuration as the regulator 3 shown in FIG. 1, except that the collector of the switching transistor 35 is connected to the base of the transfer switch 350 through the base current limiting resistor rb 'and the reverse conduction blocking diode D2 and The point where a high-voltage power supply voltage which is several V higher than the battery voltage is received from the booster circuit 31a through the resistor rc, and the OR gate 39 shown in FIG.
The only difference is that a NOR gate 303a is adopted instead of 3.

The operation of the characteristic part of this embodiment will be described below. When the switching transistor 35 is off, the high-voltage power supply voltage output from the booster circuit 31a is applied to the base of the transfer switch 350 through the diode D2 and the resistors rc and rb ', and the transfer switch 350 is turned on to turn on all three-phase. The generated current is supplied from the wave rectifier 22 to the battery 4. At this time, it is preferable that the npn bipolar transistor forming the transfer switch 350 be saturated so that the base current is sufficiently supplied to reduce the collector resistance loss.

When the switching transistor 35 is turned on, the charge accumulated in the base of the transfer switch 350 and the current output from the booster circuit 31a are absorbed by the switching transistor 35, and the collector potential of the switching transistor 35 becomes almost 0V. As a result, the transfer switch 350 is turned off. In the OFF state of the transfer switch 350, the breakdown between the emitter and the base of the transfer switch 350 causes a leakage current to flow from the emitter of the transfer switch 350 through the base, the base current limiting resistor rb ′, and the switching transistor 35. Therefore, even when the transfer switch 350 is off,
The transfer switch 350 causes power loss,
This loss has no practical problem because the leakage current is limited by the base current limiting resistance rb ′ and the switching transistor 35 is always turned off to make the leakage current zero when the key switch 1 is turned off.

According to the present embodiment, the fluctuation of the engine speed can be suppressed, and the switching transistor 35 is turned on when the engine speed becomes high and the generated voltage becomes high voltage and the battery voltage rises. Since the transfer switch 350 is turned off, it is possible to improve the fuel consumption of the magnet generator at high rotation speed. Note that the power generation control at the time of high rotation is also performed by setting the power generation period, that is, the ON period of the transfer switch 350 before and after the torque peak point of the fundamental frequency component of the torque fluctuation, as in the case of the idle rotation and below. The torque fluctuation of the engine can be reduced. In addition,
In this embodiment, the delay time ΔTd shown in FIG. 7 can be omitted or reduced.

Next, the operation of the diode D2 will be added. When the key switch 1 is turned off, the output end of the booster circuit 31a may be grounded. Then
Since the reverse withstand pressure between the emitter and the base of the transfer switch 350 is very small, a leakage current may occur from the battery 4 through the transfer switch 350, the base current limiting resistor rb ′, the resistor rc, and the booster circuit 31a. This problem is solved by the diode D2.

(Embodiment 5) Another embodiment will be described with reference to FIG. In this embodiment, the transfer switch 350 is used in the vehicle power generation device of the fourth embodiment (see FIG. 10).
Instead of omitting, the diode on the high side of the three-phase full-wave rectifier 22 is replaced with an npn bipolar transistor like the transfer switch 350, and its emitter is connected to the battery 4. Of course, the high side switches of these three-phase full wave rectifiers 22 can be controlled by the same regulator 3a as in FIG.

In this way, power loss can be reduced. The diode on the low side of the three-phase full-wave rectifier 22 can be replaced with an npn bipolar transistor, and these npn bipolar transistors can be replaced with nMOST.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing an ignition device used in Embodiment 1 of the present invention.

FIG. 3 is a voltage waveform diagram of each part of FIGS. 1 and 2.

FIG. 4 is a circuit diagram showing a second embodiment of the present invention.

5 is a timing chart showing a power generation control operation in the circuit of FIG.

FIG. 6 is a vector diagram showing a combined vector Tef of a stroke-synchronized fundamental frequency component vector Ta of fluctuation of a positive torque component generated by the engine and a stroke-synchronized fundamental frequency component vector −Tb of fluctuation of a negative torque component generated by the engine. Is.

7 is a timing chart showing a power generation control operation in the circuit of FIG.

8 is a flowchart showing a power generation control operation in the circuit of FIG.

FIG. 9 is a flowchart showing a power generation control operation according to the third embodiment of the present invention.

FIG. 10 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 11 is a circuit diagram showing a fifth embodiment of the present invention.

[Explanation of symbols]

2 is a vehicle generator 3 is a regulator (control means) 4 is a battery, 5 is an ignition device (rotation angle detection means) 21, field winding 22 is a three-phase full-wave rectifier (rectifier) 35 is a switching transistor (excitation) Current interruption switch) 350 is a transfer switch (generated current interruption switch) 22a is a transistor (generated current interruption switch).

Claims (8)

[Claims] 1. A generated current interrupt switch for interrupting a generated current of a vehicle generator that is driven by an internal combustion engine and supplies power to a battery and an electric load for a vehicle through a rectifying device, or an exciting current interrupt switch for interrupting an exciting current thereof. And a control means for controlling the generated current by intermittently controlling the switch, a vehicle power generation control device comprising a rotation angle detection means for detecting a rotation angle signal related to a rotation angle of the internal combustion engine, The control means controls the switch intermittently in synchronism with the stroke change of the internal combustion engine based on the rotation angle signal when it is determined that the engine speed is equal to or lower than the idle speed. A power generation control device for a vehicle, which reduces a change in the number of revolutions of the engine in synchronization with a change in a stroke. 2. The control means, when it is determined that the engine speed is equal to or lower than an idle speed, the generated current or the exciting current during the compression stroke period of the internal combustion engine based on the rotation angle signal. 2. The vehicular power generation control device according to claim 1, wherein the power consumption is reduced from that during the other stroke period. 3. The control means, when determining that the engine speed is equal to or lower than an idle speed, controls the generated current or the exciting current during the combustion stroke period of the internal combustion engine based on the rotation angle signal. The power generation control device for a vehicle according to claim 1, wherein the power generation control device is increased in number during the other stroke period. 4. The vehicle power generation according to claim 1, wherein the control means sets a power generation period having a predetermined phase period width before and after a torque peak time point of a fundamental frequency component of the torque fluctuation determined based on the rotation angle signal. Control device. 5. The control means sets a power generation stop period having a predetermined phase period width before and after the torque bottom time point of the fundamental frequency component of the torque fluctuation determined based on the rotation angle signal. Vehicle power generation control device. 6. The vehicle power generation according to claim 4 or 5, wherein the control means determines a target power generation rate of the power generator in accordance with a condition of a power generator load and sets the period in accordance with the target power generation rate. Control device. 7. The vehicular power generation control device according to claim 6, wherein the control means employs a signal relating to a voltage difference between a battery voltage and a predetermined reference voltage as the generator load. 8. The power generation control device for a vehicle according to claim 1, wherein the rotation angle detection means is an ignition device for the internal combustion engine.