JP2503996B2 - Control method for vehicle charging generator - Google Patents

Description

The present invention relates to a method for controlling a vehicle charging generator.

[Prior Art] A vehicle charging generator (hereinafter referred to as an alternator) is connected to an engine and its rotation speed changes in a wide range. Therefore, usually, a regulator for controlling ON / OFF of the field winding current of the alternator is provided to maintain the output voltage of the alternator at a predetermined regulated voltage regardless of the rotation speed.

The regulated voltage is set higher (for example, 14V) than the rated voltage of the battery (for example, 12V) in order to efficiently charge the vehicle-mounted battery. Therefore, when the vehicle travels at a high speed in a relatively low load state, the battery tends to be overcharged, and conversely, when the vehicle travels at a constant speed in a high load state, the battery tends to overdischarge. Furthermore, keeping the regulated voltage high unnecessarily imposes a burden on the engine and deteriorates fuel efficiency.

Therefore, for example, in Japanese Patent Laid-Open No. 59-103529, the charging / discharging state of the battery is predicted from the average conduction rate of the transistor for switching the field winding current, and the adjustment voltage is not lowered at the time of overcharging and at the time of overdischarging. A control device has been proposed in which the regulated voltage is increased to keep the state of charge of the battery proper.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional control device, when the average value for a relatively long time is taken, the average conductivity of the transistor shows the charge / discharge state of the battery well, but the average value for a short time is obtained. However, the above-mentioned average conductivity and the charging / discharging state of the battery do not always coincide with each other due to an error caused by the magnitude of the electric load, and thus the responsiveness is difficult. Also, since the conductivity of the alternator is simply detected, it is not possible to distinguish between the current flowing in the electric load and the battery charging current. However, there is a problem in that the system becomes complicated due to the need for correction depending on the detection.

The present invention solves such a problem, and can accurately detect the charge / discharge state of the battery in a relatively short time without being affected by the magnitude of the load, and based on this, maintain the optimum charge state of the battery. It is an object of the present invention to provide a method of controlling an alternator, which is capable of improving the fuel efficiency of the engine.

[Means for Solving Problems] The present invention relates to switching means for controlling a field winding current of a generator rotated by an engine to maintain an output voltage of the generator at a given set voltage, Vehicle equipped with a regulator having an output current detecting means for obtaining an output current of the generator from the conduction ratio of the switching means and the rotation speed of the generator, and a setting voltage generating means for changing a setting voltage applied to the switching means. In a generator control method, the output of the output current detecting means and the set voltage when the set voltage is set to a first set value higher than that of a vehicle-mounted battery, and the set voltage is smaller than the first set value. When the difference from the output of the output current detecting means when set to the set value is larger than a predetermined value, the set voltage generating means is the first
There is provided a method for controlling a vehicular generator, which is characterized by generating the set voltage.

[Action]

The charging current of a battery has a large voltage dependency as compared with an on-vehicle electric load, and this tendency is remarkable especially in a battery having a low charging state. Therefore, the output current difference when the battery is charged with the first set voltage and the second set voltage well represents the state of charge of the battery. Therefore, when the output current difference is large, it can be determined that the charging state is low, and the charging mode based on the first set voltage can be determined. When the output current difference is small, it can be determined that the charging state is almost full. The mode is selected.

If the second set voltage is set near the rated voltage of the on-vehicle battery, the output current at that time hardly includes the battery charging current. Therefore, if the difference between the two output currents is obtained, the battery charging current can be accurately calculated. I can know.

[Effect] According to the above control method, the battery charging current is calculated from the difference between the alternator output currents under the high adjustment voltage and the low adjustment voltage. Therefore, the battery charging current can be accurately calculated in a short time regardless of the magnitude of the electric load. The state of charge of the on-vehicle battery can be confirmed, whereby the output of the alternator can be controlled and the state of charge of the battery can be optimally maintained.

Moreover, since the output of the alternator is not unnecessarily increased, the load on the engine is reduced and the fuel consumption can be improved.

[Examples] The configuration of an apparatus for carrying out the method of the present invention will be described below.

In FIG. 1, reference numeral 1 is a regulator, the F terminal of which is connected to the field winding 22 of the alternator 2 and the E terminal of which is connected to the rectifier 21. The B terminal of the regulator 1 is connected to the battery 5 together with the charging line 4, and the IG terminal is connected to the battery 5 via the key switch 6.

Reference numeral 3 is a control device, the a terminal of which is connected to the key switch 6 and the b terminal and the c terminal of which are connected to the C terminal and F ′ terminal of the regulator 1, respectively. The ignition pulse NE is input to the d terminal of the control device 3.
In the figure, 7 is an electric load.

2 and 3, the regulator 1 and the control device 3 are shown.
Shows the details of. The regulator 1 has a switching transistor 11 that controls the excitation of the field winding 22, and the collector voltage of the transistor 11 is output as a conduction signal DF from the F'terminal. The transistor 11 is a comparator 12
It is turned on and off by the output of. Comparator 12 above
The reference voltage Vc obtained by resistance-dividing the output of the constant-voltage circuit 13 is input to the "-" terminal, and the comparison voltage Va obtained by dividing the B-terminal input by the resistors 14 and 15 is input to the "+" terminal. Is typing. A resistor 16 connected in series with a transistor 17 is connected in parallel to the resistor 15, and the transistor 17 is operated by an adjustment voltage change signal SV input from the C terminal.

In the regulator 1, the excitation of the field winding 22 is controlled so that the comparison voltage Va is always in the vicinity of the reference voltage Vc, and when the transistor 17 is off, the adjustment voltage R of the alternator 2 is a voltage close to the rated voltage of the battery 5. (For example 12.
8V), and when the transistor 17 is turned on, the regulated voltage R is set to a higher voltage (for example, 14.5V) that can efficiently charge the battery 5.

The control device 3 (FIG. 3) includes a microcomputer 31, a power supply circuit 32 for operating the microcomputer 31, and a wave shaping circuit 33.
34, the conduction signal DF and the ignition pulse NE are input to the microcomputer 31 via the circuits 33 and 34, respectively.

FIG. 4 shows a control program flow chart of the microcomputer 31.

Steps 101 to 108 show the processing in the charging mode. In step 101, the adjustment voltage R is set high by the adjustment voltage change signal SV and the battery 5 is charged. This state is maintained for 10 minutes (step 102), and then the conduction rate is calculated from the conduction signal DF and the engine speed is calculated from the ignition pulse NE (step 103). From the conduction ratio of the switching transistor 11 and the engine speed, as shown in FIG. 5, the output current I _o of the alternator 2 can be known. Obtain the output current I _o1 (step 10
Four). In step 105, the regulated voltage R is not lowered, and after a marginal time of 1 minute to reach the steady state, the conduction rate and the engine speed are calculated again, and the output current I _o2 under the regulated voltage is low.
Is obtained (steps 106 to 108).

Since the output current I _o2 is a current value when the regulated voltage R is close to the battery rated voltage, the output current I _o2 almost does not include the charging current for the battery 5 and is substantially equal to the consumption current of the electric load 7. Therefore, in step 109, the output currents I _o1 , I
The difference IB of _o2 is calculated, and this difference current IB corresponds to the battery charging current under the above high adjustment voltage. The magnitude of the battery charging current IB corresponds well to the charging state of the battery 5, as shown in FIG. 6, and when the current IB is large, the battery 5 is in an uncharged state.

Then, the battery charging current IB is 2 amps (A)
In the above, the process returns to step 101 again, the charging mode is repeated, and if it is smaller than 2 amperes, the process proceeds to step 110 and thereafter.

Steps 110 to 115 show the processing in the charge stop mode. In this mode, the regulated voltage R remains set low and the battery 5 is not charged. The counters N and T are reset (step 110), and the counter T is incremented about every 1 second (step 111). If the conductivity is 100% during this increment, the counter N is incremented (steps 113 and 114). Counter T
When T exceeds TL, both counters T and N are reset (step 112). This TL is set to, for example, 600 (which corresponds to 10 minutes).

When the counter N exceeds NL, the charging mode is entered (step 115). NL is set to 480 (which corresponds to 8 minutes), for example. Thus, within 10 minutes, more than 8 minutes
When 100% conductivity appears, the battery is expected to discharge and the charging mode is entered.

As described above, according to the control method of the present invention, the battery charging current is calculated from the difference between the alternator output currents under the high adjustment voltage and the low adjustment voltage, and the battery charge state is calculated for a relatively short time based on the difference. Since the accurate and reliable detection is performed, it is possible to maintain the battery charge state properly with quick response without unnecessarily increasing the output of the alternator.

Moreover, since the output of the alternator is not excessively large, the load on the engine is reduced and the fuel consumption can be improved.

[Brief description of drawings]

1 is a block diagram of a device for carrying out the method of the present invention, FIG. 2 is a circuit diagram of a regulator, FIG. 3 is a block diagram of a controller, FIG. 4 is a program flowchart of the controller, and FIG. FIG. 6 is an output current characteristic diagram of the vehicle charging generator, and FIG. 6 is a correlation diagram between the charging current and the battery charging state. 1 …… Regulator 11 …… Switching transistor (switch means) 2 …… Charge generator 22 …… Field winding 3 …… Control device 31 …… Microcomputer 5 …… In-vehicle battery 7 …… Electrical load

Claims (2)

(57) [Claims] 1. A switching means for controlling a field winding current of a generator rotated by an engine to keep an output voltage of the generator at a given set voltage, a conduction rate of the switching means and the power generation. A method for controlling a vehicle generator, comprising: a regulator having an output current detecting means for obtaining an output current of the generator from the number of revolutions of the machine, and a set voltage generating means for changing a set voltage applied to the switching means, When the set voltage is set to a first set value which is higher than that of the vehicle battery, the output of the output current detecting means and the set voltage when set to a second set value which is smaller than the first set value A control method for a vehicular generator, wherein the set voltage generation means generates a first set voltage when a difference from the output of the output current detection means is larger than a predetermined value. 2. The control method for a vehicle generator according to claim 1, wherein the second set value is set to approximately the rated voltage of the battery.