JPH0458735A - Charger for battery of vehicle - Google Patents

Abstract

PURPOSE:To prevent the wasteful power consumption resulting from battery deterioration by judging it that the battery has deteriorated when the voltage difference between an alternator and the battery is over the set value for a certain period, and lowering the alternator voltage so as to approximate it to battery voltage. CONSTITUTION:A regulator 10 makes the alternator voltage follow the target value by feedback control when a battery is not deteriorated yet, and changes the target value over to high or low according to the signal form a control unit 30. And if the voltage difference between the alternator voltage Va and the battery voltage Vb, V=Va-Vb, is not less than a set value, V>= set value, there is possibility of the battery 11 having deteriorated, so it follows that, if the difference between the reference voltage Vo at some point of time and the voltage difference V after ten seconds, Vo- V, is positive on comparison, the battery voltage Vb is not restored even if charged, so it judges it that the battery 11 has deteriorated. And under the condition of high control operation, the target value of alternator voltage is set to the proper value a little higher than the battery voltage Vb, and the useless charge from the alternator 7 to the battery 11 is prevented.

Description

[Detailed description of the invention] [Industrial application field] It is something.

U Prior Art] Generally, automobiles are equipped with an alternator whose generated voltage is controlled by a regulator. A portion of the electric power output from the alternator is supplied to various electrical devices, and the remainder is supplied to a battery. The battery is now charging. Here, if the charging rate of the battery decreases, problems such as the starter not rotating sufficiently when starting the engine or shortening the life of the battery occur.

Therefore, we focused on the fact that the battery voltage decreases when the charging rate of the battery decreases, and developed a battery that detects the battery voltage and, when it is low, increases the voltage generated by the alternator to promote battery charging. Charging devices have been proposed (for example, Japanese Patent Application Laid-open No. 1983
(Refer to Publication No.-37849).

[Problem to be solved by the invention] By the way, batteries generally deteriorate in a relatively short period of time.
When the battery deteriorates, the battery voltage decreases.

For this reason, in the conventional battery charging device described above, which increases the output voltage of the alternator when the battery voltage drops, when the battery deteriorates, the generated voltage of the alternator is constantly increased, resulting in unnecessary power being supplied to the battery. Continue. Therefore, there is a problem that engine output is wasted and the fuel efficiency of the engine is reduced.

Note that battery deterioration can be determined by measuring the specific gravity or sulfuric acid concentration of the battery fluid, so if you perform such measurements on a daily basis, you can prevent the above problems. It is extremely troublesome to do this on a daily basis.

The present invention has been made in view of the above conventional problems, and is a vehicle battery that can easily detect battery deterioration and prevent wasteful power consumption due to battery deterioration. The purpose is to provide a charging device.

[Means for Solving the Problem] In order to achieve the above object, the invention of claim 1 provides a vehicle battery charging device including an alternator that charges the battery and a regulator that controls the voltage generated by the alternator. , the voltage difference between the alternator's generated voltage and the battery voltage is detected, and if this voltage difference continues for a certain period of time to exceed a set value, it is determined that the battery has deteriorated. The invention according to claim 2 is characterized in that, in the vehicle battery charging device, when it is determined that the battery has deteriorated,
To provide a charging device for a vehicle battery, characterized in that the voltage generated by an alternator is lowered to approach the battery voltage.

"Operations and Effects of the Invention" According to the invention of claim 1, the voltage difference between the voltage generated by the alternator and the battery voltage is detected, and if this voltage difference is a positive value, the alternator starts generating electricity. Therefore, if this voltage difference continues, the battery voltage will gradually recover if the battery has not deteriorated. , the voltage difference gradually becomes smaller.On the other hand, if the battery has deteriorated, even if such a voltage difference continues, the battery voltage will not recover and the voltage difference will not change.Therefore, the voltage difference will not change. Comparing the voltage difference before and after a certain period of time has elapsed, if the voltage difference decreases, the battery has not deteriorated, while if the voltage difference does not change, it means that the battery has deteriorated.

The present invention focuses on this fact, and if the voltage difference before and after a certain period of time does not change, it is determined that the battery has deteriorated.

Therefore, it is possible to easily determine the presence or absence of battery deterioration based on the alternator's generated voltage and battery voltage, which can be easily and automatically detected. This eliminates the need for troublesome work such as checking the temperature.

Moreover, according to the invention of claim 2, the same effect as that of claim 1 can be obtained. Furthermore, when the battery deteriorates, the generated voltage of the alternator is lowered to bring it closer to the battery voltage, so more power than necessary is not consumed to charge the battery, and the fuel efficiency of the engine is improved.

[Example] Examples of the present invention will be specifically described below.

As shown in FIG. 1, the engine CE has a throttle valve l
The air-fuel mixture is sucked in through the intake passage 2 in which the air-fuel mixture is interposed, and the power obtained by combusting the air-fuel mixture is outputted from the crankshaft 3.

A crank pulley 4 is provided at the front end of the crankshaft 3, and a belt 9 is installed astride this crank pulley 4, a water pump pulley 6 that drives a water pump 5, and an alternator pulley 8 that drives an alternator 7. The water pump 5 and alternator 7 are wound around each other so that the crankshaft 3 rotates the water pump 5 and the alternator 7 .

As will be explained later, the alternator 7 is a common automotive alternator that supplies power to various electrical devices and also charges the battery 11. This alternator 7 is feedback-controlled by a regulator 10 (voltage regulator) so that the generated voltage follows a target value.
This target value is set to high (14, 4
V) or low (12,8V).

A main conducting wire 12 is connected to a positive terminal of the battery 11, and a negative terminal is connected to a vehicle body 13.

Note that if the terminal of the electrical device is connected to the vehicle body 13, it will be electrically connected to the negative terminal of the battery 11.

A starter 15 and a starter switch 16 are interposed in a first branch conductor 14 branching from the main conductor 12 . Further, a second branch conductor 18 is provided which branches from the main conductor 12, and this second branch conductor 18 is connected to the B terminal of the alternator 7 (see FIG. 2). In addition, the main conductor 12 is connected to various electrical equipment l7 (1) such as an air conditioner.
(only one shown) is connected.

As will be explained later, the voltage generated by the alternator 7 (hereinafter referred to as alternator voltage) is switched to high or low depending on the driving condition of the vehicle, and when the battery 11 deteriorates, the alternator voltage is lowered. A control unit 30 comprised of a microcomputer is provided to control the alternator voltage so that the alternator voltage approaches the battery voltage.

This control unit 30 includes, as control information,
The output signal ST of the starter switch 16, the engine rotation speed Ne output from the rotation speed sensor 22, the water temperature THW output from the water temperature sensor 23, and the idle switch 2
an idle switch signal ID output from 4, a full open switch signal WOT pressed from the full open switch 25,
Current sensor output 1 al output from current sensor 2I
t and an electric load switch signal EL output from the electric load switch 26.

Note that the alternator voltage is input to the control unit 30 via the first voltage introduction conductor 31 , and the battery voltage is input to the control unit 30 via the second voltage introduction conductor 32 .

As shown in FIG. 2, the alternator 7 includes a stator 41 (electromagnet) equipped with a star-connected stator coil, and a rotor 42 (electromagnet) equipped with a field coil and rotationally driven by the alternator pulley 8 (see FIG. 1). (electromagnet) is provided. When the rotor 42 rotates, three-phase AC power is induced in the stator 41, and this three-phase AC power is
It is rectified into DC power by a rectifier 43 made up of six diodes, and after this DC power has pulsations absorbed by a capacitor 44, it is output from the B terminal (generated voltage output terminal). Further, a part of the three-phase AC power generated by the alternator 7 is supplied to the rotor 42 after being rectified by an auxiliary rectifier 45 .

Battery voltage is always introduced into the regulator IO from the battery 11 via the S terminal (battery sensing terminal), and when the ignition switch 46 is turned on, power is supplied from the battery 11 via the L terminal. ing.

In addition, between the L terminal and the ignition switch 46,
A check clamp 47 and an adjustment resistor 48 are provided. The regulator 10 also has a G terminal (alternator voltage control terminal) connected to the collector of the first transistor T of the control unit 30, a T terminal connected to the positive side of the rotor 42, and a negative terminal of the rotor 42. The F terminal (field current terminal) connected to the side and the vehicle body 13
An E terminal (earth terminal) connected to the terminal is provided.

The regulator 10 includes second to fourth transistors T, -
T4, first to fourth diodes D1 to D4, and first to eighth resistors R1 to R8, which constitute an electric circuit as shown, which will be described later. As will be explained, in response to a signal from the control unit 30, the alternator voltage is controlled by switching the alternator voltage between high and low, and lowering the alternator voltage when the battery deteriorates. Note that the fourth transistor T4 is a two-stage transistor, and the third diode D3 is a Zener diode.

Hereinafter, a control method for alternator voltage control will be explained according to the flowcharts shown in FIGS. 3(a) and 3(b).

In step S1, the starter switch signal ST, engine speed Ne, electric load switch signal EL, idle switch signal ID, current sensor output 1 alt, full open switch signal WOT, and water temperature THW are read.

In step S2, a comparison is made to determine whether or not the engine is starting.

In this embodiment, under normal conditions (when the battery is not degraded), the alternator voltage is controlled to 14.4V (high control) or 128V (low control) depending on the driving condition of the vehicle. However, during high control, the load on the alternator 7 increases and the engine output decreases. For this reason, when the vehicle is in an operating state where it is necessary to reduce the load as much as possible or where a high output is required, low control is performed regardless of other conditions.

Therefore, when starting the engine, that is, when the starter switch signal ST is on and the engine speed Ne is less than the starting speed (for example, 300 r, p, m, etc.), reduce the load as much as possible and immediately turn on the engine CE. In order to start the engine, low control is performed.

Although not shown in this flowchart, when the throttle is fully open (full open switch WOT), which requires high output,
It is preferable to perform low control even when the vehicle is on) or during acceleration.

The operating characteristics of the regulator IO in the above high/low control will be explained below. Under normal conditions (when the battery is not degraded), the regulator IO causes the alternator voltage to follow the target value by feedback control, and sets this target value to high (14, 4 V) or low (12, 4 V) according to the signal from the control unit 30. 8V)
It is now possible to switch to

Basically, to follow the target value, when the alternator voltage exceeds the target value, the collector and emitter of the fourth transistor T4 are electrically cut off (hereinafter simply referred to as "cut off"), and the rotation is stopped. Current no longer flows through the child 42 (field coil) and the alternator voltage decreases.On the other hand, when the alternator voltage falls below the target value, the fourth
This is performed by on/off control in which the collector and emitter of the transistor T4 are electrically connected (hereinafter simply referred to as conductive), current flows through the rotor 42, and the alternator voltage increases.

Specifically, when the alternator voltage exceeds the target value, the Zener diode D3 conducts, and the positive voltage introduced via the third resistor R3 is applied to the base of the third transistor T3, causing the third transistor T3 to conduct. Therefore, the base voltage of the fourth transistor T4 becomes 0 and the current is cut off, so that no current flows to the rotor 42. On the other hand, when the alternator voltage is below the target value, the Zener diode D3
Since the third transistor T3 is cut off, the fourth transistor T4 becomes conductive, and a current starts to flow through the rotor 42.

In addition, the target value is basically switched between the voltage Vi between X2 (input voltage) and the voltage VO between Y-2 (output voltage).
This is done by changing the ratio Vi/Vo. In other words, the output voltage ■0 is applied to the Zener diode D3,
Zener diode D3 becomes conductive when this ◯◯ exceeds a certain break voltage. Therefore, Vi/Vo
The larger the value, the more conductive the Zener diode D3 becomes at a higher alternator voltage. Therefore, by changing Vi/Vo, the target value can be changed freely.

Utilizing this, the target value is switched between high and low by switching Vi/V○ into two levels, large and small.

Specifically, when the NO1 signal is applied to the base of the first transistor TI of the control unit 30,
Since the first transistor T conducts and the G terminal is grounded via the first transistor T, the base voltage of the second transistor T becomes 0 and the power is cut off. For this reason, the fifth
A current flows through the resistor R6, and at this time the voltage ratio (Vi/Vo)
is the resistance ratio (R3゜R4, Rs series resistance value)/(R4
, Rs series resistance value). in this case,
Since the resistance ratio is small, the target value is low (12.8V).

On the other hand, when a low signal is applied to the base of the first transistor T, the first transistor T.

is cut off, and a positive voltage is applied to the base of the second transistor T, making it conductive. Therefore, current no longer flows through the fifth resistor R5, and at this time the voltage ratio (Vi/Vo) changes to the resistance ratio (R3
, R4, Rs (series resistance value)/(resistance value of R). In this case, since the resistance ratio is large, the target value is high (14.4V).

As a result of the comparison in step S2, if it is the time of starting (YES)
), preferably when the throttle is fully open, and also when accelerating (), step S8 is executed and low control is performed.

At this time, a high signal is applied to the base of the first transistor T of the control unit 30, and along with this,
As mentioned above, the target value is set to 2.8V per month, and the alternator voltage is turned on and off so that it follows the target value of 128V.
Off-feedback control is performed. Thereafter, in step S19, a timer activation flag F, which will be described later, is set to 0, and the process returns to step S1.

On the other hand, as a result of the comparison in step S2, if the engine is not starting (NO), and preferably, the throttle is not fully open or accelerating, then in steps 83 to S6, the following four low control prohibition conditions are met. It is determined whether or not the following conditions are satisfied, and if even one of the low control prohibition conditions is satisfied, high control is performed.

(2) When the electric load switch signal EL is on, that is, when the electric device 17 with a large capacity is operating, low control is prohibited (step S3).

This is because the low control may not be able to supply sufficient power due to the large demand for power.

■When the water temperature THW is below 0°C, that is, when the engine temperature or outside temperature is low, low control is prohibited (
Step S4). This is because the activity of the battery 11 decreases at low temperatures.

■Current sensor output! When alt is greater than or equal to IOA, that is, when the total power consumption of the vehicle is large, low control is prohibited (step 95). This is because there is a possibility that sufficient power cannot be supplied.

■The idle switch signal is on and the rotation speed Ne
is 300 r, p, m or more, that is, in the idle deceleration state, low control is prohibited (
Step S6). In idle deceleration state, alternator 7
This is because by increasing the load, the braking effect is enhanced (electromagnetic brake) and charging of the battery 11 is promoted.

As a result of the comparisons in steps 83 to S6, if all low control inhibition conditions are not satisfied (all No), low control is performed in step S8.

On the other hand, as a result of these comparisons, if even one low control prohibition condition is satisfied (at least one is YES), step S
At step 7, it is compared whether the fail flag F fail is 1 or not. This fail flag F fail is initially 0
is set, and when it is determined that the battery 11 has deteriorated in steps S11 to S22, which will be described later, l is set.

As a result of the comparison in step S7, if Pfail=0 (No), it has not been determined that the battery 11 has deteriorated, so high control is performed in step S9.

At this time, a low signal is applied to the base of the first transistor T1 of the control unit 30, and accordingly,
As mentioned above, the target value is set to 14.4V, and the alternator voltage is turned on and off so that it follows the target value of 144V.
Off-feedback control is performed.

In step Sll, alternator voltage Va and battery voltage vb are read.

In step S12, the voltage difference ΔV=Va−Vh is calculated.

In step S13, it is compared whether the voltage difference Δ■ is 0.4■ or more. If the voltage input V is less than 04■, it is considered that the battery voltage vb has sufficiently increased to follow the alternator voltage Va, and the battery 11 has not deteriorated and the charging rate is high. Therefore, if the voltage input V is less than 0.4 .mu., it is determined that the battery 11 has not deteriorated.

As a result of the comparison in step S13, if ΔV<0.4■ (No), the timer operation flag F is set to O in step S19.
After this is set, the process returns to step Sl.

As a result of the comparison in step S23, if AV≧0.4■ (NO), there is a possibility that the battery 11 has deteriorated. Therefore, compare the reference voltage difference ΔvO at a certain point with the voltage difference Δ■ after 10 seconds, and if the difference ΔVo-8V is positive and 0.1V or less, charge at a high voltage. This also means that the battery voltage vb has not recovered, so
It is determined that the battery 11 has deteriorated.

In step S14, it is compared whether the timer operation flag F is 1 or not. This timer operation flag F is basically set to 1 in step S22 when determining whether or not the battery 11 has deteriorated, and is set to 0 in step S19 when the determination operation is completed.

As a result of the comparison in step S14, if F=O (No
), since the battery deterioration determination has started this time, the current voltage difference Δ■ is stored as the reference voltage difference ΔVo in step S20, the timer TM is set (started) in step S21, and the timer operation flag F is set in step S22. After the month is set, the process returns to step S1.

On the other hand, as a result of the comparison in step S14, if F=1 (YES), the timer TM is counting, so it is checked in step S15 whether or not time has elapsed, that is, whether 10 seconds have elapsed since the start of battery deterioration determination. It is compared whether or not. As a result of the comparison, if the time amplifier is not used, battery deterioration judgment cannot be performed again, so step 3
Steps 16 to S19 are skipped and the process returns to step S1.

On the other hand, as a result of the comparison in step S15, if the time is up, then in step S16, 0. IV≧ΔVo−ΔV
A comparison is made to see if ≧0. As a result of the comparison, ΔVo−
ΔV>0. If it is IV (NO), the voltage difference Δ in 10 seconds
It is thought that V is decreasing and the charging rate is increasing, so the voltage difference ΔV of 0.4■ or more is simply due to a decrease in the charging rate, and the battery 11 is deteriorating. It is determined that this has not been done. Thereafter, the timer operation flag F is set to 0 in step S19, and the process returns to step Sl. Note that in the case of ΔVo−ΔV<0, it means that the charging rate of the battery is decreasing even though the alternator 7 is generating power at a high voltage. In such a case, the deterioration of the battery 11 cannot be determined, so the process returns to step S1 via step S+9.

On the other hand, as a result of the comparison in step S16, 0.1■≧ΔV
If o-ΔV≧0, the battery voltage has not recovered even though it is being charged, so it is determined that the battery 11 has deteriorated, and the battery deterioration flag F fail is set in step S]7. is set to 1, and an alarm indicating deterioration of the battery 11 is issued in step S+8. Then, in step S19, the timer activation flag F is set to 0, and the process returns to step Sl.

By the way, as a result of the comparison in step S7, Ffai1=
If it is 1 (YES), it is determined that the battery 11 has already deteriorated, so control for battery deterioration is performed in step SIO.

That is, under operating conditions under which high control should normally be performed, the target value of the alternator voltage is set to an appropriate value slightly higher than the battery voltage vb, and wasteful charging from the alternator 7 to the battery 11 is prevented. Therefore, the battery is charged with the minimum necessary voltage according to the battery voltage, preventing wasteful consumption of electric power, and improving the fuel efficiency of the engine CE. Although not shown in detail, such a change in the target value is also performed by appropriately changing the voltage ratio Vl/Vo.

When such alternator voltage control is performed, when the high control is performed, the deterioration of the battery 11 is determined every 10 seconds as t+, tt, ts, etc., as shown in FIG. It will be done. In this case, although the voltage difference ΔV is 0.4 V or more between t and t, the voltage difference ΔV
is 0. Since it has decreased more than IV, battery 1! is determined to have not deteriorated. On the other hand, since the voltage difference ΔV does not change between t and t3, it is determined that the battery 11 has deteriorated, and at time t3, the alternator voltage (curve G1) drops to around the battery voltage (curve G2). It will be done.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of an engine equipped with a battery charging device according to the present invention. FIG. 2 is a flowchart showing the configuration of the alternator and regulator. FIG. 4 is a diagram showing changes over time in alternator voltage and battery voltage when voltage control according to the present invention is performed. CF...Engine, 3...Crankshaft, 7...Alternator, lO...Regulator, ll...Battery, 12...Main conductor, 13...Vehicle body, 17...
・Electrical equipment, 30...control unit. Patent applicant Mazda Motor Corporation agent Patent attorney: 1 person named Haga

Claims (2)

[Claims] (1) In a vehicle battery charging device that is equipped with an alternator that charges the battery and a regulator that controls the voltage generated by the alternator, the voltage difference between the voltage generated by the alternator and the battery voltage is detected, and the voltage A vehicle battery charging device characterized in that the battery is determined to be deteriorated when the difference is equal to or greater than a set value for a certain period of time. (2) The vehicle battery charging device according to claim 1, characterized in that when it is determined that the battery has deteriorated, the voltage generated by the alternator is lowered to approach the battery voltage. Vehicle battery charging device.