JP3267018B2 - Control device for vehicle generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a vehicular generator, and more particularly to a vehicular system capable of appropriately changing a generated voltage to effectively prevent overcharging of a battery and improving fuel efficiency of a vehicle required for power generation. The present invention relates to a control device for a power generator.

[0002]

2. Description of the Related Art In a conventional control device for a vehicle generator, a constant power generation voltage (for example, 14.5 V) which is considerably higher than a battery open terminal voltage (for example, 12.8 V) in order to quickly charge a battery. However, in this case, when the electric load is smaller than the power generation capacity, there is a possibility that the charging of the battery is promoted and the battery is brought into a fully charged state. If this state continues even after full charge, the load on the engine may be increased to deteriorate fuel economy and the battery may be overcharged.

In Japanese Patent Application No. 4-183166, for example, the conductivity (ie, the power generation rate of the generator) of a switching transistor that energizes the field winding (rotor coil) of the generator is detected, and the power generation voltage target value is detected. When the power generation rate is equal to or higher than a predetermined value in a low state, the battery is slightly discharged, and the target value is changed to a higher value to promote battery charging. It has been proposed to return the target value to the original low value on the assumption that the battery is charged well when the battery becomes small.

[0004]

The control device proposed above exhibits an excellent function of avoiding overcharging of the battery and properly maintaining the state of charge, and improving the fuel efficiency of the vehicle by not generating wasteful power. However, there are still points to be improved. That is, the power generation rate of the generator can be an indicator of the state of charge of the battery, but when the power generation capacity of the generator is relatively large with respect to the battery and the electric load connected in parallel to the battery, the power generation rate Does not necessarily reflect the state of charge of the battery well. This is because the power generation margin of the generator is relatively large, so that even if the battery is not charged and requires a large charging current, there is a surplus in the power generation of the generator. Therefore, in such a case, if the power generation voltage target value is immediately reduced when the power generation rate falls below a predetermined value (for example, 100%), a problem occurs that the battery remains uncharged.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem, and a vehicular generator capable of always maintaining a good charge state of a battery and improving the fuel efficiency of a vehicle even if the power generation margin of the generator changes. Is provided.

[0006]

Referring to FIG. 6, the structure of the invention according to claim 1 of the present application will be described. It has a stator winding and a field winding, is driven to rotate by an engine, and supplies electric power to an electric load. A generator that supplies and charges the battery;
Rotation speed detection means for detecting the rotation speed of the generator, power generation voltage control means for controlling the power generation voltage of the generator to maintain a target value, and power generation rate detection means for detecting the power generation rate of the generator , The power generation rate is equal to or less than one under a power generation voltage target value .
When the accumulated time that is equal to or greater than the predetermined value exceeds a certain value, the generated voltage target value is changed to a higher value, and in the state where the generated voltage target value is changed to a higher value, the generator rotation speed is lower than the predetermined rotation speed and the power generation rate is reduced to the second value. of the target value change means for returning to the original low value the generated voltage target value when it becomes smaller than the predetermined value, when the target value changing means returns the generated voltage target value based on the low value, given Delay means for giving a delay time. According to the second aspect of the present invention, the delay time is the power generation
When the rotation speed of the machine is low, it is changed shortly
are doing. In the invention according to claim 3, the delay time is specified.
May be shortened when the input of the electrical load is detected.
It is characterized by.

[0007]

In the control device having the above-described configuration, the power generation rate is reduced during the control in which the target value of the generated voltage is reduced to suppress the charging of the battery.
If it is equal to or greater than the first predetermined value, it is determined that the battery may be discharged, and when the accumulated time of that state exceeds a certain value, the target power generation voltage target value is changed to a higher value to promptly charge the battery. Do. On the other hand, when the generator speed is lower than the predetermined speed and the power generation rate is lower than the second predetermined value,
The power generation voltage target value is returned to the original low value, but a predetermined delay time is added when returning. That is, when the power generation margin of the generator is relatively large with respect to the battery and the electric load, even if the power generation rate becomes smaller than the other predetermined value, the battery may not be sufficiently charged. Therefore, if the return of the power generation voltage target value to the original low value is delayed, the charging of the battery proceeds rapidly during this time, resulting in a good charge state. The predetermined time for returning the target value to a low value is effective even if it is constant irrespective of the relative magnitude of the power generation margin, and is further increased if it is changed according to the relative magnitude of the power generation margin. The effect is obtained. Thus, overcharging of the battery is avoided and wasteful power generation is not performed, so that the fuel efficiency of the vehicle is improved.

[0008]

Embodiment 1 In FIG. 1, a generator 1 includes a stator coil 11 serving as a stator winding and a rotor coil 1 serving as a field winding.
2, and a full-wave rectifier 13. The rotor coil 12 is driven to rotate by the engine 7, and the power generation capacity increases and decreases according to the number of rotations. The rotor coil 12 is turned on by the switching transistor 31 of the generated voltage control circuit 3.
-OFF energized. The operation of the transistor 31 is controlled by the output of the comparator 32. The comparator 32 supplies the generated voltage target value signal Vreg from the D / A converter 33 and the feedback voltage signal V
F has entered. As a result, the battery voltage follows the target value given to the D / A converter 33 via the I / O port 52 of the target value changing circuit 5.

The target value changing circuit 5 includes an arithmetic unit (CPU)
The CPU 51 includes signals from the power generation rate detection circuit 4, the throttle switch detection circuit 81, and the vehicle speed detection circuit 2 via the I / O port 52, and performs the procedure described below. To change and set the generated voltage target value Vreg. The power generation rate detection circuit 4 receives the collector voltage of the transistor 31 and detects the conductivity, that is, the power generation rate, with a sufficiently short time average. The throttle detection switch 81 detects the fully closed state of the accelerator, and detects the idle state and the deceleration state based on the detection of the fully closed state and the detection value of the engine speed (generator speed) detection circuit 2. That is, if the engine speed is equal to or less than a predetermined value when the accelerator is fully closed, it is determined that the engine is idle.

An idle speed control device (ISC) 82 is provided, and controls the engine speed to a set speed output through the I / O port 52 in an engine idle state. Operating power is supplied from a constant voltage power supply 86 to each of the above circuits by turning on a key switch 83. An electric load 85 such as a headlamp, a blower motor, and an electric fan is connected in parallel to the battery 6 via a load switch 84.

FIG. 2 shows a processing program of the CPU.
This program is started, for example, by a timer interrupt every 10 ms. In step 101, the generated voltage target value Vreg is set to 1
3V, and reset the counters α and β to 0, respectively. The idle speed in the idle state is 600
rpm. The above 13V takes into account that the open terminal voltage when the battery is fully charged is 12.8V. In this state, if the state of charge of the battery is near full charge, the battery 6 is hardly charged, and The power supply to the vehicle is also reduced, reducing the burden on the generator and improving fuel efficiency.

In step 102, it is determined that the vehicle is being decelerated.
If the vehicle is decelerating, the target value Vreg is increased to 15 V, and the energy wastefully consumed by braking is stored in the battery 6.
(Step 103). In step 105, V
It is checked whether reg1 is 13 V, and the process proceeds to step 106 and subsequent steps.

By increasing the target value Vreg only during deceleration, the braking energy during deceleration can be effectively regenerated to the battery. If the target value Vreg is returned to the original low value immediately after deceleration, the flow during deceleration is reduced. Due to the charging current, the open terminal voltage of the battery rises for a short period. By utilizing this, the load current is extracted from the battery and the amount of power generated by the generator 1 can be reduced, so that the burden on the engine is further reduced, and the fuel efficiency is further improved.

In step 106, it is checked whether the power generation rate (Duty) is equal to or higher than A (for example, 90 to 100%). When the power generation rate is equal to or higher than A, there is a high possibility that the battery is discharged to the electric load. Then step 107,
At 108, the counter α is counted up. If the count value exceeds a predetermined value B, it is determined that the battery 6 needs to be charged, and Vreg1 (= Vreg, see step 104) is increased to 14.5 V (step 109). Thereby, quick charging of the battery 6 is started. In step 110, the counter α is reset, and the counter β is set to 5
Set to.

After the power generation voltage target value Vreg is increased to 14.5 V, steps 105 to 11 are executed.
Proceed to 1 to check if it is idle. This idle state is confirmed by fully closing the accelerator and lowering the engine speed. If the engine is in the idle state, the idle speed control is performed in step 112 so that the average duty within a predetermined time is 80 to 99%, and in this state, it is confirmed whether the idle speed Ne has become equal to or less than E. This E is, for example, 650 r, which is close to the lower limit value (600 rpm) of the idle speed.
pm.

If Ne ≦ E, the process proceeds to step 114 and the following.
If uty is F or less (for example, 100%), the counter β
Is counted up (step 115), and if it is larger than F, it is counted down in a range up to 0 (step 11).
6). When the counter β becomes equal to or more than G (for example, 10) in step 117, the process proceeds to step 118, where a fixed delay time T is set. When the delay time T elapses, Vreg1 is returned to 13V (step 1).
19), the idle speed is also reduced to 600 rpm (step 120).

That is, the above steps 114 to 117
It was confirmed that the state where the power generation rate was relatively small at a sufficiently low engine speed continued for a long time, and then Vreg1 was increased to 13 V
In step 118, a delay time T is added. This effect will be described below.

FIG. 3 shows the relationship between the battery charge rate and the battery charge current. As the battery charge rate increases, the battery charge current rapidly decreases. Each circle in the figure indicates a point in time when the power generation rate Duty becomes equal to or lower than a predetermined value F (100%), and the vehicle A has a relatively large power generation margin with respect to the battery and the electric load. B has a relatively small power generation margin.

As can be seen from the figure, in the vehicle A having a relatively large power generation margin, although the state of charge of the battery is still insufficient at about 60% and a relatively large charging current is being supplied, the power generation is relatively small. The rate is below 100%. Therefore, if the power generation voltage target value Vreg is immediately reduced to 13 V at this stage, the battery 6 remains uncharged.

Therefore, when a predetermined delay time T is given in step 118, each circle mark in the figure shifts to each triangle mark by charging at Vreg = 14.5 V during this period, and the charging state of both vehicle A and vehicle B is improved. Is done. In particular, the state of charge of the vehicle A is significantly improved. The reason is that when the charging rate is low, a large charging current flows and charging proceeds rapidly.

For example, when the delay time T is 10 minutes,
In vehicle A, a charging current of about 30 A (but gradually decreasing) is supplied to the battery, and the capacity of about 5.0 AH is restored. Assuming that the full charge capacity of the battery is 28 AH, the battery charge rate rises by about 17% to nearly 80%. On the other hand, in the vehicle B, during this time, a charging current of about 10 A is supplied to the battery, and the capacity of about 1.6 AH is restored. This means that the full charge capacity of the battery is the same as that of vehicle A,
The battery charging rate rises by about 6%, and the battery charging rate rises from a low value of the order of 80% to a high value.

Thus, a fixed delay time T is given irrespective of the type of vehicle and the physique of the generator so that the power generation rate becomes 100%.
%, The battery charge is continued for a while at a high voltage even after the battery voltage falls below% to prevent variation in the state of charge of the battery when control is executed to suppress charging of the battery due to a difference in power generation margin of the generator. It is possible to guarantee a proper charging state.

The same can be said for the same vehicle.
That is, there are various idling states, and the relative magnitude of the power generation margin of the generator with respect to the battery or the like changes in each state. This is shown in FIG. 4. When the transmission is in the N range, the generator speed (ie, engine speed) is relatively high and the power generation margin is sufficient, so that the power generation rate is 100% at the stage where the battery charge rate is low. Cut.

When the side brake is applied in the D range, the power generation margin is relatively small because the generator speed is low, and the power generation rate falls below 100% at a higher battery charge rate. . Further, in the idling state in which the foot brake is depressed, the brake lamp as the electric load is turned on, so that the power generation margin becomes relatively smaller, and the power generation rate falls below 100% when the battery charging rate is further improved.

In such a case, as described above, FIG.
By giving the constant delay time T in step 118, a good battery charging rate can be achieved without any variation in any idling state.

In the above embodiment, when the ISC control is not performed, steps 112, 113 and 120 are omitted. Further, steps 115 to 117 for increasing the certainty of the determination are not always necessary. In this case, the idling and deceleration states can be determined based on the vehicle speed instead of the engine speed. That is,
If the vehicle speed is equal to or lower than a predetermined value (for example, 3 km / h) when the accelerator is fully closed, it is determined that the vehicle is idling. If the vehicle speed is equal to or more than a predetermined value (for example, 5 km / h) when the accelerator is fully closed, it is determined that the vehicle is decelerating.

[0027]

Embodiment 2 In the above embodiment, the delay time T in step 118 is fixed, but if the time T is changed in accordance with the relative size of the power generation margin of the generator, the variation in the battery charging rate can be further reduced. It can be kept small and always keep a good charge state.

For example, as shown in FIG. 5, it is determined in step 201 whether an electric load has been applied, and in accordance with the determination result, it is determined in step 202 or lower or step 205 or lower whether the transmission is in the D range. The delay time T is set to four types of T1 to T4. That is, when the electric load is applied in the idling state and the transmission is in the D range and the generator rotation speed (that is, the engine rotation speed) is low, the power generation rate becomes a predetermined value (for example, 100%) as described above. Below is where the battery charge rate is relatively high. Therefore, the delay time T1 is set to be the shortest.

Conversely, when the electric load is not applied, the transmission is in the N range, and the generator rotation speed is high, the power generation margin is relatively large, so that the power generation rate falls below 100%. Is where the battery charge rate is relatively low. Therefore, the delay time T4 is the longest. Thus, if T1 <T2 <T3 <T4 is set, the variation in the battery charge state is smaller and better when the control for suppressing the charge to the battery is executed, regardless of the fluctuation of the power generation margin of the generator. Becomes

[0030]

As described above, according to the control device of the present invention, even if the power generation margin of the generator changes, the charge state of the battery can always be maintained satisfactorily regardless of the power generation margin, and the engine fuel efficiency can be improved. Can also be achieved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a control device according to an embodiment of the present invention.

FIG. 2 is a program flowchart of a CPU of a target value changing circuit.

FIG. 3 is a graph illustrating a relationship between a battery charging rate and a battery charging current according to a vehicle type.

FIG. 4 is a graph illustrating a relationship between a battery charging rate and a battery charging current by various states of idling.

FIG. 5 is a program flowchart of a CPU of a target value changing circuit according to another embodiment of the present invention.

FIG. 6 is a diagram corresponding to claims.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 generator 2 engine speed detection circuit (speed detection means) 3 power generation voltage control circuit (power generation voltage control means, delay means) 4 power generation rate detection circuit (power generation rate detection means) 5 target value change circuit (target value change means) ) 6 Battery 7 Engine

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 7/24 H02J 7/16

Claims (3)

(57) [Claims] 1. A generator having a stator winding and a field winding, which is driven to rotate by an engine and supplies electric power to an electric load and charges a battery, and detects a rotation speed of the generator. Rotation speed detection means, power generation voltage control means for controlling the power generation voltage of the generator to maintain a target value, power generation rate detection means for detecting the power generation rate of the generator,
When the accumulated time during which the power generation rate becomes equal to or more than the first predetermined value under one power generation voltage target value exceeds a predetermined value, the power generation voltage target value is changed to a higher value, and the generator is The rotation speed is lower than the predetermined rotation speed and the power generation rate is
A target value changing means for returning the power generation voltage target value to the original low value when the power generation voltage target value becomes lower than the second predetermined value; and A control device for a vehicle generator, comprising: a delay unit for giving a predetermined delay time. 2. The method according to claim 1, wherein the delay time is such that the number of revolutions of the generator is
2. The method according to claim 1, wherein when the value is low, the value is changed to a short time.
4. The control device for a vehicle generator according to claim 1. 3. The method according to claim 1, wherein the delay time is a time when a specific electric load is applied.
When the detection of
The control device for a vehicle generator according to claim 1.