JPS63298078A - Diagnosing and warning device for on-vehicle battery - Google Patents

Abstract

PURPOSE:To prevent next rotation from being disabled by warning a deficiency in electric charging right after an engine stops if a battery diagnosing means judges that the next engine start is impossible from the remaining electric charging quantity of the battery. CONSTITUTION:When a microcomputer 9 is powered on, said microcomputer measures the release voltage E0 of the battery 1 first. Then when an ignition switch 5 is turned on, the voltage E0 is updated. Then when the engine is started with a start switch 3 on, the battery voltage at the start and the discharging current by a current detector 6 are measured. The computer 9 inputs the voltage E0, battery terminal voltage, discharging current, etc., and computes the remaining electric charging quantity after the engine stops. Then it is judged whether or not the battery life is longer than a reference value and it is judged from the remaining charging quantity of the battery whether or not the engine can be restarted next. Consequently, the computer 9 outputs a warning to a speaker 16 right after the engine key is turned off when a fact that the next engine start is impossible is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a battery diagnosis/warning device for diagnosing the condition of a vehicle battery.

[Conventional technology]

In recent years, in the automotive field, devices have been put into practical use that diagnose the lifespan of in-vehicle batteries and issue a warning to the driver if it is determined that the battery life is running out or has reached the end of its lifespan. ing. This type of battery diagnostic device calculates the internal resistance from the discharge characteristics during battery discharge, calculates the battery open circuit voltage using a predetermined formula, and calculates the battery The battery life is diagnosed by determining the specific gravity and comparing this internal resistance and battery specific gravity with a reference value (life diagnosis map).

[Problem that the invention seeks to solve]

As described above, the conventional battery diagnostic device diagnoses the battery life using parameters such as internal resistance and specific gravity of the battery, and issues an alarm to let the driver predict when it is time to replace the battery. By the way, when driving a car, the charging performance of the battery may deteriorate over time while driving, resulting in insufficient charging, and as a result, it becomes difficult to start the engine the next time after a certain period of time has elapsed. However, conventional battery life diagnosis devices are only capable of predictively diagnosing battery life, and do not have sufficient functionality to judge the battery state of charge from the standpoint of the possibility of restarting the engine. No consideration was given to this.

The present invention has been made in view of the above points.

The purpose is to provide an in-vehicle battery diagnostic device that can monitor the state of charge of the battery during driving, determine the possibility of starting the engine next time, and notify the driver of charging problems. be.

[Means for solving problems]

The above object includes a battery voltage detection means, a battery current detection means, a battery voltage detection value detected by the battery voltage detection means before or at the time of starting the engine, and a battery voltage detection value detected by the battery current detection means after the engine start. calculation means for calculating the battery remaining charge amount at the time the engine is stopped based on the integrated value of the battery charging current; a battery diagnostic means that compares i with a preset reference value and determines whether or not the next engine start is possible based on the remaining battery charge amount; and the battery diagnostic means determines that the next engine start is impossible. If it is determined that
This is achieved by providing an alarm means for issuing an alarm to warn of insufficient charging immediately after the engine is stopped.

[Effect]

The remaining charge amount of the battery when the vehicle operation is stopped can be determined from the initial remaining charge amount of the battery when the vehicle operation is started and the integrated value of the charging current during driving.

The present invention calculates the battery remaining charge amount at the beginning of the operation described above from the battery voltage detection value before starting the engine (or at the time of starting the engine), and the calculation means stops the engine based on the battery voltage detection value and the integrated value of the battery charge amount. This is to calculate the remaining charge amount of the battery at the time. Such a calculation can be performed, for example, by converting both the battery voltage detection value and the battery charging current integrated value into the battery fluid specific gravity that serves as a barometer for battery charging.

The battery remaining charge amount calculated by the calculating means is compared with a reference value by the battery diagnosis means, and if the battery remaining charge amount is less than the reference value, it is determined that the engine cannot be started next time. . Here, the reference value is determined to determine whether the remaining charge amount when the engine is stopped is sufficient, assuming that the next operation will be performed after a predetermined time (for example, the next day).

If it is determined that it is impossible to start the engine for the next drive, the warning means will issue an alarm immediately after the engine stops, allowing the driver to notice that the battery is insufficiently charged before leaving the driver's seat, and to take appropriate measures to deal with it. Measures may be taken, such as battery recharging, battery life checks, replacement, etc.

〔Example〕

A first embodiment of the present invention will be described based on FIGS. 1 to 4.

Figure 1 is a circuit diagram of an automobile battery that is charged by a gasoline engine and its surroundings. In the figure, 1 is the battery;
2 is a starter motor driven by battery 1, and 3 is a starting switch. 4 is an ignition device, and an ignition coil 41
．． It consists of a contact 422 and a spark plug 43. 5 is an ignition switch (key switch). A current detector 6 detects the current of the battery 1, and converts the current value into a voltage. 17 is a temperature detector that detects the temperature around the battery 1 and converts it into voltage. 7 is an A/D converter, and the A/D converter 7 converts the voltage of the battery 1, the battery current value detected by the current detector 6, and the temperature detection value detected by the temperature detector 17 into digital signals. and input it to the microcomputer 9, which will be described later. 8 is a waveform shaping circuit that shapes the primary voltage of the ignition coil 41 to obtain a pulse train. 9 is a microcomputer operated by a clock signal, and RA
Built-in M (not shown) and ROM (not shown),
Perform digital calculations. This microcomputer 9 is composed of a C-MOS, and is always powered on and in operation even when the engine is stopped.

The microcomputer 9 calculates the open circuit voltage Eo of the battery 1.
, ambient temperature T, battery terminal voltage and discharge current at the time of engine start, charging current after engine start, etc. are input as digital signals, and as described later, battery life diagnosis and remaining charge after engine stop are performed. It has a function of calculating the amount, etc., and also has a function of determining whether the life of the battery is longer than the standard, and also has a function of determining whether the next engine restart is possible from the remaining charge amount of the battery, The data (digital signals) of these determination results are sent to the D/A converter 10. D/A converter 10 converts a digital signal from microcomputer 9 into an analog voltage. 1
Reference numeral 1 denotes an audio amplifier, which amplifies the power of the analog output of the D/A converter 10.

A speaker 12 is installed near the driver's seat of the automobile and transmits audio to the driver.

The operation of the above configuration will be explained using the flow chart of FIG. First, when the microcomputer 9 is powered on, the program is started in step 20. After initializing the register in step 21, in step 22 the open circuit voltage Eo of the battery 1 is set.
and measure the temperature T. Thereafter, in step 23, it is determined whether the ignition switch 5 has been turned on. When the ignition switch 5 is turned on, the battery voltage is applied to the ignition coil 41, so that the output of the waveform shaping circuit 8 rises to a high level. By inputting this high level signal to the microcomputer 9, the ON state of the ignition switch 5 is detected. When the ignition switch 5 is in the off state, steps 22 and 23 are repeated, and the battery open circuit voltage E is
o and temperature T data are updated. At this time, R
It is stored in AM.

If the ignition switch 5 is turned on in step 23, the process proceeds to step 24, and data collection of Eo and T is stopped. Next, when the driver turns on the start switch 3 to start the engine, the contacts 42 open and close, and sparks fly to the spark plug 43 in accordance with the rotation of the engine, starting the engine. When the engine is started, the pulses of the primary voltage are converted into a pulse train (rotational pulse) by the waveform shaping circuit 8 and input to the microcomputer 9 (step 2).
4). If the rotation pulse of the engine is detected in step 24 and the engine starting state is detected, step 25
The battery voltage (discharge voltage) and discharge current at the time of starting (starter operation) are measured. Here, since the current of the starter motor 2 is large and easy to detect, the current at this time is taken as the battery discharging current. and obtain current data. Note that the discharge current and discharge voltage were collected using the same method as in JP-A-60-74920, that is, the discharge current and the battery voltage value at that time were taken out several times when the operating waveform of the starter was in a stable state. This is to find the average value of each.

The discharge W1 current-voltage data obtained here is used when calculating the battery life as described later.

Next, the process moves to step 26, and the presence or absence of the circuit pulse is checked again. If the rotation pulse is still detected, it means that the engine continues to rotate, and step 27.2
Proceed to step 8. As the engine continues to rotate, the battery begins to be charged, and in step 27, the battery charging current and temperature T are measured. Here, similarly to step 22, when the temperature T is the lowest in the past week, the value T min
is recorded.

Therefore, in step 28, the sum 'II l is calculated. Generally, the relationship between charge q and current i is J″i, = 9 (1), and the charge can be found by integrating the current value over time. , the time integration is performed by integrating the current values that are inputted moment by moment).Based on such calculations, the amount of charge to be charged to Panteri 1 is determined.As long as the engine continues to rotate, , repeat steps 26, 27 and 28.

Integral calculation continues. When the rotation of the engine has stopped, the process moves to step 29 and first the battery life is calculated. The battery life is calculated by determining the battery liquid specific gravity ρ and internal resistance γ.

-ρ generally uses the open circuit voltage Eo, and in the case of a 12V system, p = (Eo -5,04) / 6 - according to the following formula (experimental formula).
It is expressed as (2). Also, the internal resistance γ is the discharge current value ■
Using the terminal voltage E at ', γ=(EoE)/I'...(3)
It can be found as Here, Eo is the battery open voltage value immediately before the ignition switch 5 is turned on.

Then, the values of ρ and α calculated in this way are compared with the life determination map shown in FIG. 3, and it is determined whether or not they are within the battery life range. In the life determination map shown in FIG. 3, the horizontal axis shows the specific gravity ρ of the battery fluid, and the vertical axis shows the internal resistance γ.

The battery life range determined by these correlations (the shaded area) was defined as the battery life range I and ■, but it was divided into two stages, I and II, depending on the progress of battery life. ing. The identification conditions at this time are (1) When ρ>ρ2 and γ>γ2, the battery life region (
2) ρ>ρ1 and γ>γwork and ρ 1- ρ 2 ρ 1-
When ρ is 2, the battery life is in the region ■.

The battery life range (2) is set to be an indicator when the battery life is short, and when the battery life range (2) has been reached, it is set to be an indicator when the battery life has reached its limit.

Next, in step 30, the remaining charge amount of the battery at the next time the engine is started is estimated. In this embodiment, the battery remaining charge amount is calculated by converting it into battery liquid specific gravity. The relationship between battery temperature T and superpower Eo is Ea = Eo (25°C) + 0.012 (T-25) - (4
), and by substituting equation (4) into equation (2) to find the change in ρ with respect to temperature change, a p / a T = 0.002 −
(5) is obtained. Assuming that the battery temperature has decreased to the lowest temperature Tm1n in the past week measured in step 22.27, temperature correction of the specific gravity ρ is performed using the following formula.

ρmin =, o+o, o02 (T resistance n-T)
(6) Here, ρ and T are values calculated from the measured values immediately before starting the engine. Next, according to equation (1),
The minimum specific gravity ρmin is corrected based on the amount of charge charged in the battery 1 while the engine is rotating.

The coefficient of this correction amount (corrected battery remaining charge amount) differs depending on the battery capacity, but ρmin = , omin +K ・ΔQ
- Obtained by executing the formula (7).

However, K: proportionality coefficient ΔQ: Charge amount (current x time) It is.

Next, from the viewpoint of startability of the starter motor, the minimum specific gravity ρm
It is determined whether the engine is in the difficult-to-start region based on in and the lowest temperature Tm1n. FIG. 4 is a map showing the starting difficulty region based on Tmin and ρmin. The boundary line with this difficult-to-start region is the battery 1. It can be determined experimentally based on the combination of starter motor 2 and engine performance.

Next, the process proceeds to step 31, in which an audio signal is generated to notify the driver of the determination results of the lifespan and remaining charge amount. Regarding the speech synthesis technology, by using the speech synthesis technology known in Japanese Patent Application Laid-open No. 55-2234, Japanese Patent Application Publication No. 55-4003, etc., and compressing the information of the voice characteristic parameters and registering it in the memory device, It is possible to store voice messages for a long time with a small memory capacity. Applying the above technology,
The following audio warnings will be given.

(i) When the battery life range ■ is reached: ``The battery is about to reach the end of its life.'' (ii) When the battery life range ■ is reached: ``Please replace the battery.'' (iii) Difficulty starting. When reaching the area "Insufficient charge. Please charge the battery." After the above process, the process returns to step 22 and 23, and the battery open voltage Eo and temperature T are maintained until the ignition switch 5 is turned on. Take measurements.

According to this embodiment, a warning of battery abnormality is given before the driver stops the engine and leaves the driver's seat.

Since the system prompts for battery replacement or supplementary charging, troubles such as inability to start can be avoided, which has a safety effect. Furthermore, since the warning is given by voice, it has a great effect on the driver's anxiety. Furthermore, this embodiment does not simply estimate the remaining battery charge amount from the battery terminal voltage, but also takes into account the integrated value of the battery charging current during operation to detect the remaining charge amount, so the remaining charge amount can be determined with high accuracy. You can know.

Furthermore, in this embodiment, when determining the remaining charge amount of the battery, the lowest temperature within a certain period is memorized based on the temperature data detected by the temperature detector, and this lowest temperature is stored before the next operation. Since the worst-case condition is predicted based on the assumption that the battery temperature will drop to the same temperature, the driver can be warned if the engine cannot be started next time under any circumstances.

Another embodiment of the invention is shown in FIG. In FIG. 5, parts given the same reference numerals as in FIG. 1 are the same parts as in FIG. In FIG. 5, 13 is an output register, which holds the digital signal output from the microcomputer 9.

14 is a resistor, 15 is a transistor, and 16 is a display lamp (light emitting element). In this embodiment, the display lamp 16 provides a warning instead of an audio warning. FIG. 6 shows a flow chart of this embodiment. The flow chart of FIG. 6 is constructed almost the same as that of FIG. 2, with only step 31a being different. That is, in step 31a, a battery abnormality warning is issued not by an audio warning but by a blinking pattern of the display lamp 16. FIG. 7 shows an example of the blinking pattern. The blinking cycle is set so that it becomes faster in the order of battery life region I, ■, and difficult-to-start region.

In this embodiment, the warning circuit is simple, and there is no need to have data for voice synthesis as in the first embodiment, and the ROM capacity can be small.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to monitor the state of battery charge during driving and notify the driver of insufficient battery charge before the driver leaves the driver's seat, thereby preventing the driver from suddenly being unable to start the car the next day. This avoids problems such as: This increases vehicle safety.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, FIG. 2 is a flowchart for explaining the operating state of the first embodiment, and FIG. 3 is a flow chart for determining the battery life in the first embodiment. FIG. 4 is a characteristic diagram representing a map used as a criterion for determining the remaining charge of the battery in the first embodiment, FIG. 5 is a circuit diagram showing the second embodiment of the present invention, and FIG. 7 is a flowchart for explaining the operating state of the second embodiment, and FIG. 7 is an explanatory diagram of waveforms for the indicator lamp for explaining the operating state of the second embodiment. 1...Battery, 2...Starter motor, 3...
Starting switch, 4... Ignition device, 5... Ignition switch (key switch), 6... Battery current detector, 7
... A/D converter, 9... Microcomputer (
calculation means. battery diagnosis means), 12... speaker, 13...
Output register, 16...Display lamp, 17...Temperature detector/
f Agent Patent Attorney Katsuo Ogawa Me $2 Prisoner $3 Kuimo 4 Meichi 1tO-30-20-10θ lθ 20 Kage Hi Onan (
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Claims (1)

[Claims] 1. A battery voltage detection means, a battery current detection means, a battery voltage detection value detected by the battery voltage detection means before or at the time of starting the engine, and a battery voltage detection value detected by the battery current detection means. a calculation means for calculating the remaining charge amount of the battery at the time when the engine is stopped based on the integrated value of the battery system charge flow after the engine is started; and a reference value preset for the remaining charge amount of the battery when the engine is stopped; A battery diagnostic means compares and determines whether or not it is possible to start the engine next time based on the battery remaining charge amount, and when the battery diagnostic means determines that the next engine start is impossible, A diagnostic/warning device for a vehicle battery, comprising an alarm means for issuing an alarm to warn of insufficient charging immediately after the key is turned off. 2. In claim 1, the in-vehicle battery diagnostic/warning device includes a temperature detector that detects the ambient temperature of the battery, and the calculation means detects the temperature detected by the temperature detector. Temperature data is input, and the lowest temperature within a certain period of at least one day among these temperature data is also used as a reference, and the remaining charge of the battery is determined based on the assumption that the battery liquid specific gravity will change when the lowest temperature is reached. A diagnostic/warning device for automotive batteries that is configured to compensate for temperature. 3. In claim 1 or 2, the calculation means is configured to calculate the battery open voltage before starting the engine, the battery voltage at the time of starting the engine, and the discharge voltage detected by the battery voltage detecting means and the battery current detecting means. The battery diagnosis means has a function of inputting a current and indirectly calculating battery internal resistance and battery specific gravity based on these input data, and the battery diagnostic means compares the battery internal resistance and battery liquid specific gravity with a reference value. A vehicle battery diagnostic/warning device having a function of determining battery life based on battery life. 4. In any one of claims 1 to 3, the alarm means includes a voice synthesizer and a speaker, and the battery diagnosis means detects the alarm according to the remaining charge amount of the battery or the stage of battery life. A vehicle battery diagnostic/warning device configured to select and generate multiple patterns of audio signals. 5. In any one of claims 1 to 3, the warning means comprises an indicator lamp, and the diagnostic means blinks the indicator lamp in accordance with the remaining charge amount of the battery or the step of battery life. A diagnostic/warning device for automotive batteries that is set to change the cycle.