JPS6237347B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an on-vehicle battery checker that notifies the remaining capacity of an on-vehicle battery.

Traditionally, battery remaining capacity checkers use current
Determine the voltage 5 seconds after the start of 150A discharge,
There is a known device in which the device is determined to be good if the measured voltage is higher than the set voltage, and is determined to be defective if the measured voltage is lower than the set voltage. Also, there are cases where this 5th second is the 10th or 20th second. This type of device measures voltage by passing a current of 150A for a long time of 5 seconds or more, so if the current is passed through a resistor, 12 volts x 150 A x 5 seconds = 9000 Joules of heat is generated, which is a large amount of electricity. A capacitive resistor is required,
It was unsuitable for automotive use. In addition, conventionally,
As shown in Publication No. 52-98933, there are some batteries in which the discharge time is extremely short, several hundred microseconds, and the discharge is repeated multiple times at a constant cycle, but in general, in-vehicle storage batteries have such extremely short discharge times. It is usually difficult to respond within hours, so it is not suitable for automotive use.

In view of the above points, the present invention shortens the time during which a large load current is passed, thereby allowing a resistor with a small size to be used as a load, and also allows judgments to be displayed for a relatively long time by holding measured values during a check. By doing this, it is possible to accurately and easily notify the determination, and furthermore, by generating a check signal according to the operating state of the vehicle engine, the remaining capacity of the battery can be constantly detected without putting a burden on the driver. The object of the present invention is to provide an on-vehicle battery checker that can perform a battery check at an appropriate time.

The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 of the accompanying drawings is an electrical wiring diagram showing the overall configuration of the first embodiment of the present invention, in which numeral 1 represents an on-vehicle battery whose remaining capacity is checked, and numeral 2 represents a load resistor through which a large current flows. 10 is a constant voltage section that generates a constant voltage and supplies it to each circuit. 20 is a storage unit which inputs the voltage of the vehicle battery 1 through the (+) voltage detection terminal b and (-) voltage detection terminal c, and when the check signal does not come, it inputs the value corresponding to the terminal voltage of the battery. It is always output, and when a check signal is received, it holds and outputs the value corresponding to the lowest battery voltage. 30 is a display section that receives the output from the storage section 20 and displays the voltage value. Reference numeral 50 denotes a check signal shaping section, which shapes the waveform of a check start signal when it is applied to the input terminal e from the operation detecting section 90 that detects the engine operating state. 6
0 is a check signal time limit section, which generates a check time signal at the output terminal 60a for a certain period of time (approximately 200 msec in this embodiment) when a check start signal is applied to the input terminal e, and also generates a check signal at the output terminal 60a for a certain period of time (approximately 200 msec in this embodiment) after the check signal is generated. In this embodiment, the check signal is not generated again until approximately 6 seconds have elapsed, and during this fixed period of time, a hold signal is output to the output terminal 60b for holding the value corresponding to the lowest battery voltage in the storage unit 20. occurs in 70 is a load resistance drive section,
The check time signal from the check signal time limit unit 60 turns on transistors 701 and 702 to drive the relay coil 703, closes the relay contact 704, and connects the load resistor 2 to the (+) terminal of the vehicle battery 1.
It is connected between the terminal and the (-) terminal. 7
05,706 is a diode for absorbing back electromotive force. Reference numeral 80 is a clock oscillator, which supplies the check signal timer 60 with a reference clock (approximately 1280 in this embodiment).
Hz) from the output end 80a. 9
0 is an operation detection unit that detects the operating state of the engine and generates a check start signal. For example, it detects this before or immediately after starting the engine and automatically generates a check start signal. .

Next, a case will be described in which a check start signal is applied to input terminal e. When the input terminal e changes from the "1" level to the "0" level, the output of the check signal shaping section 50, which is composed of three inverters and resistors, changes from the "1" level to the output from the terminal 50a. The output of the D flip-flop 601 of the check signal timer 60 changes from "1" to "0". The counting circuit 603 is then released from reset and receives clock pulses from the clock oscillator 80.
The input is counted through the NOR gate 604, and approximately
After 200 msec, the output terminal _Q9 changes from "0" to "1", and the output Q of the D flip-flop 602 becomes "0".
becomes “1”. Therefore, the NOR gate 605 inputs the output of the D flip-flop 601 and the Q output of the D flip-flop 602, and outputs a check time signal to its 60a terminal which becomes "1" for about 200 msec and then returns to "0". Further, the D flip-flop 601 operates until the output _Q14 of the counting circuit 603 becomes "1" (approximately 6 in this embodiment).
2 seconds) and the output remains at "0" during that period, no check time signal is generated at the output terminal 60a of the check signal time limit section 60, no matter how many check start signals are received during this time. In this embodiment, the D flip-flops 601 and 602 are CD4013, a well-known IC made by RCA, and the counting circuit 603 is a CD4020.

Now, when the output terminal 60a becomes "1" level, the transistors 701 and 70 of the load resistance drive section 70
2 are electrically connected to operate the relay coil 703 and close the contact 704, and the load resistor 2 is connected between the (+) terminal a and the (-) terminal d of the vehicle battery 1. At this time, in this example, the load resistance 2 is 50mΩ
Therefore, when the battery voltage is 12V, a large current of 240A flows. However, since the current flow time is short, only 200 msee, the amount of heat generated is about 576 Joules, and the dimensions and shape of this load resistor 2 are 70 x 30
Even with a size of about 5 mm, it can have sufficient power capacity. While a large current is flowing through the load resistor 2, the storage unit 20 measures the voltage of the vehicle battery 1. If the remaining capacity of the battery is low, the battery terminal voltage drops below the specified value. Capacity reduction can be detected and notified.

Next, the storage unit 20 stores the battery voltage, which decreased when the large current was flowing, after the large current has finished flowing (approximately
200msec later) to improve display regularity. This storage section 20 is an operational amplifier 205
and 215, diode 208, capacitor 21
4. A negative peak hold circuit consisting of a relay 212 and the like is the main component.

The battery voltage divided by resistors 201 and 202 passes through protective diodes 203 and 204 to non-inverting input terminal 205 of operational amplifier 205.
applied to a. When the check signal is not received, the normally closed contact 212a of the relay 212 is closed, and the operational amplifiers 205 and 215 are connected to the relay 212, the protective resistor 211, the memory capacitor 214, and the feedback resistor 2.
07. Through the feedback diode 206, the entire amplifier functions as an amplifier with an amplification factor of 1. A voltage corresponding to the battery voltage appears at the output 215a of the operational amplifier 215, is output to the terminal 20a through the resistor 216, and is applied to the display section 30 (in this case, an ammeter). on the other hand,
When the check signal is applied to the check signal timer 60, the holding signal at the output terminal 60b changes from "1" to "0" level, and the output of the counting circuit 603 changes from "1" to "0" level.
Until Q ₁₄ goes from “0” to “1” level (approximately
6.2 seconds) lasts. Therefore, when the output terminal 60b becomes "0" level, the output of the inverter 220 of the storage section 20 becomes "1" level and is applied to the base of the relay drive transistor 222 through the resistor 221, and the transistor 222 becomes conductive and the relay drive transistor 222 becomes conductive.
12 contacts 212a are opened. At this time, operational amplifiers 205, 215, diodes 206, 208, 2
10 and memory capacitor 214, resistor 207,
209 and 211 constitute a negative peak hold circuit. The operational amplifier requires a sufficiently high input impedance and minimal offset current, offset voltage, and offset drift, and in this example, an IC CA3140 manufactured by ROA was used. In addition, diodes with low reverse leakage current are required, and here we use IS1588 and 210, also manufactured by Toshiba Electric, for 206 and 208.
A 2SK30A gate-source junction was used. The memory capacitor needs to have a small leakage current in relation to its capacity, and in this example, a laminated polyester film capacitor manufactured by Siemens was used.

The operation of this peak hold circuit will be described below. Immediately after the normally closed contact 212a of the relay 212 opens, the voltage of the storage capacitor 214 maintains the value immediately before the normally closed contact 212a opens. The voltage on the capacitor is the output 215 of the operational amplifier 215.
It also appears in a, and the operational amplifier 205 is connected by the resistor 207.
It is applied to the inverting input terminal 205b of. Now amplifier 2
When the input voltage to the non-inverting input terminal 205a of the amplifier 205 becomes lower than the voltage stored in the capacitor 214, the output of the amplifier 205 decreases and the diode 206
is cut off, diodes 208 and 210 are turned on, and the voltage across capacitor 214 is lowered.
It is fed back to the amplifier 205 through the amplifier 215 again, and stabilizes when the voltage of 205b, that is, the output voltage of 215a, becomes equal to the voltage of the input terminal 205a.

Next, the non-inverting input terminal 205a of the amplifier 205
We will explain when the voltage starts to rise after reaching its lowest value. The voltage of the storage capacitor, i.e. 21
The voltage of 5a and the voltage of 205b follow the voltage of 205b as described above and decrease until it reaches the lowest value of the voltage of 205b, but if the voltage of 205a tries to become even slightly higher than the voltage of 205b, the output voltage of amplifier 205 increases. However, the feedback diode 206 becomes conductive, and the output of the amplifier 205 becomes higher than the input voltage of the amplifier 205a by the forward drop voltage of the diode 206. on the other hand,
Diodes 208 and 210 are cut off, and the voltage on storage capacitor 214 is held and output by amplifier 215. This output is applied to the terminal 205b by the feedback resistor 207, but since the impedance of the diode 206 is low, the amplifier 2
It has almost no effect on 05. Therefore, amplifier 2
05 and amplifier 215 work separately, and input terminal 2
Even if the voltage of 05a increases, the lowest value continues to be output to the output terminal 215a.

Here, the resistor 209 applies the voltage of the output terminal 215a to the diodes 208 and 210, causing the diode 208 to bear most of the reverse voltage, and the diode 210 to operate with a small reverse voltage. Since the leakage current is small for a small reverse voltage, the voltage of the capacitor 214 can be maintained for a long time.

In the above-described embodiment, the operation detection section 90 detects the operating state of the engine and generates a check start signal, but specifically, it is most suitable for detecting the remaining capacity of the battery itself. This is also the time when it is easy to give a warning to the driver and make him/her aware of the situation. That is, it is preferable to generate the check start signal after the key switch is turned on and before the starter is driven, or immediately after the engine is started, or immediately after the engine is stopped. The lag operation detection section 90 may have a configuration that detects the turning on of a key switch, a configuration that detects the output of the alternator or the engine speed, or a configuration that detects the opening of the ignition switch.

Furthermore, although the check signal time limit section 60 has configured the time limit digitally, it may also be created analogously, such as a time limit circuit using a resistor and a capacitor.

Next, a second embodiment shown in FIG. 2 will be described. In the storage unit 20 of the first embodiment, when not checking, the output of the amplifier 215 should be a value corresponding to the battery voltage, but the battery voltage drops too much and the output voltage V of the constant voltage unit 10 in FIG. 1 drops. Then, the operational amplifiers 205 and 215 no longer operate normally. Therefore, as shown in Figure 2, the resistor 21
7 and a relay 218 are added, and the output of the amplifier 215 is applied through the resistor 216 to the normally open contact 218a of the relay 218, and the battery terminal voltage is applied through the resistor 217 to the normally closed contact 218b, so that the relay 218 is activated. When the constant voltage section output V drops to such an extent that it cannot be used, the value from the normally closed contact 218b is output to the terminal 20a, so the battery voltage
A value corresponding to the battery terminal voltage is obtained at the terminal 20a until it reaches OV. When the battery voltage is sufficiently high, it is similar to the first embodiment.

Next, a third embodiment shown in FIG. 3 will be described. In the storage section 20 of the first embodiment, the time for holding the value corresponding to the lowest value of the battery voltage is a certain period of time after the check signal is received. In order to extend this to an arbitrary time, inverter 220 in Fig. 1 is replaced with inverter 219 as shown in Fig. 3.
Change to NAND gate 223. Inverter 21
9, add a check signal from terminal 50a,
When a hold signal is applied from terminal 60b to one input of the NAND gate, the hold signal disappears approximately 6.2 seconds after the check signal arrives, but if the check signal is continued to be applied, the check signal is output. During this period, the NAD gate output is at the "1" level, the transistor 222 is made conductive, the normally closed contact 212a of the relay 212 is opened, and the negative peak hold state described above can be maintained. A check signal of arbitrary length can be obtained by providing the operation detecting section 90 with a switch or the like that is unrelated to the operating state of the engine, so that the structure is such that the check start signal can be generated at any arbitrary time.

Although an ammeter is used as the display unit 30 in this embodiment, it may be analog or digital, and may be not only visual but also auditory such as musical scale expression, or any other means that humans can identify. It may also be expressed as

In addition, in the storage unit 20 of the first embodiment, a value corresponding to the battery voltage is always output when no check signal is received, but the output is fixed to a voltage corresponding to the maximum value of the battery voltage or more. You may also do this.

Furthermore, in the storage unit 20 of the second embodiment, the battery terminal voltage was applied to the normally closed contact 218b of the relay 218 through the resistor 217;
In addition to 7, any passive element network may be used as long as it outputs a value corresponding to the battery terminal voltage and is not affected by the power supply voltage V.

As described above, in the present invention, in response to a check signal generated in accordance with the operating state of the vehicle engine, the check signal timer generates a relatively short time signal longer than the response time of the vehicle battery. Only during this time limit, the load resistance drive section connects a predetermined load resistance to the battery to discharge the battery, so the battery can always be checked at an appropriate time without putting any burden on the driver, and the load resistance It is possible to detect and notify an abnormal decrease in the remaining battery capacity when a check signal is generated by further suppressing the heat generated by the check signal, and since it is equipped with a memory unit that can hold the measured value for a certain period of time during the check, the detection can be completed in a short time. This has the advantage that it is possible to easily and reliably detect changes in battery voltage that would otherwise be difficult to detect.

Next, as an embodiment of the present invention, even if the load resistor is connected to the battery for a relatively short time, if the load resistor is connected continuously, the temperature of the load resistor gradually increases and the load resistor is destroyed. However, since the timer signal is not generated again until a certain period of time has elapsed after checking the check signal timer, it is possible to prevent damage to the load resistor.

In addition, since the holding time of the measured value at the time of checking can be set to an arbitrary time, it is possible to obtain accurate information with plenty of time without any misunderstandings.

In addition, since it is configured to output a value corresponding to the battery voltage at times other than when checking, it becomes possible to determine whether the battery is normal in any operating state.

Furthermore, when the power supply voltage of the circuit drops to such a level that the active elements cannot operate, the measured value can be output through the passive element, so even if the battery voltage drops to near OV, the value can be accurately determined. Become.

[Brief explanation of the drawing]

Fig. 1 is an electrical wiring diagram showing a first embodiment of the device of the present invention, Fig. 2 is an electrical wiring diagram showing a second embodiment of the device of the invention, and Fig. 3 is a third embodiment of the device of the invention. FIG. 3 is an electrical wiring diagram showing an example. 1... Vehicle battery, 2... Load resistance, 10
... Constant voltage section, 20 ... Storage section, 30 ... Display section, 50 ... Check signal shaping section, 60 ... Check signal time limit section, 70 ... Load resistance drive section, 80
. . . Clock oscillation section, 90 . . . Operation detection section.

Claims (1)

[Scope of Claims] 1. An operation detection unit that generates a check signal for an on-vehicle battery depending on the operating state of an on-vehicle engine;
In response to this check signal, the timer signal is activated for a certain period of time longer than the response time of the vehicle battery.
a load resistance drive section that connects a predetermined load resistance between both terminals of the vehicle battery for the predetermined period of time according to the time signal from the check signal timer; An on-vehicle battery checker comprising: a memory section that operates in response to the received voltage and holds a value corresponding to the lowest terminal voltage of the on-vehicle battery for a certain period of time; and a display section that notifies the output of the memory section. 2. The check signal timer according to claim 1, wherein the check signal timer is configured so as not to generate the timer signal even if the check signal is generated again for a certain period of time after the end of the timer signal. In-vehicle battery checker. 3. Claims 1 or 2, characterized in that the storage unit is configured to be able to arbitrarily change the time period during which the value corresponding to the lowest value of the battery terminal voltage is to be held in accordance with an external operation. The in-vehicle battery checker described in Section 1. 4. The on-vehicle battery checker according to claim 1, wherein the storage section is configured to always output a value corresponding to the battery terminal voltage when the check signal is not received. 5. The storage unit according to claim 4, wherein the storage unit is configured so that when the power supply voltage drops to such a level that the active element cannot operate normally, the passive element can output a value corresponding to the battery terminal voltage. In-vehicle battery checker.