JPS6114969B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a battery capacity display device, and more particularly, to a battery capacity display device that indirectly detects and displays the charging capacity of a vehicle-mounted battery based on the engine cranking rotation speed at the time of engine startup.

Generally, starting an automobile engine becomes difficult as the charging capacity of the battery decreases, the battery deteriorates, and the outside temperature decreases. Therefore, in order to always ensure good starting conditions, it is necessary to monitor the charging capacity of the installed battery.

Conventionally, methods for directly measuring the charge capacity of this type of battery include a method by measuring the specific gravity of battery fluid and a method by discharging. However, the specific gravity of the battery liquid is not uniform within the battery, and the apparent specific gravity increases due to the floating of living matter due to deterioration, making the former method difficult in practice.
Furthermore, in the latter method, the battery is discharged while measuring its capacity, so even if it becomes possible to measure the capacity, it is not suitable for measuring the capacity of a vehicle-mounted battery.

The present invention has been made in view of the above points, and an object thereof is to provide a battery capacity display device that can indirectly detect and display the charge capacity of a battery.

In order to achieve the above object, the present invention includes a timer circuit that responds to turning on of a starter contact of an ignition switch and determines a detection time, a rotation detector that converts the engine rotation speed into an electrical signal and outputs it, and the timer circuit. This battery capacity display device includes a display device that detects and displays the battery capacity based on the output signal of the rotation detector obtained during the detection time determined by the circuit.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the relationship between outside air temperature and engine speed at engine startup. Curves A, B,
C and D indicate the charging capacity of the battery, respectively, and curve A
is fully charged, curve B is 3/4 charged, curve C is 1/2 charged, and curve D is 1/4 charged. As can be seen from this figure, when looking at curve A, the engine speed N changes depending on the temperature change of +20°C to -20°C even for the same charging capacity. This is curve B,
The same applies to C and D. Furthermore, when looking at the engine speed N with the temperature constant, for example, 20° C., the engine speed N changes depending on the charging capacity of the battery. This means that the charging capacity of the battery can be determined by measuring the engine speed N when the engine is started.
Note that a curve E intersecting each of the curves A, B, C, and D indicates an area where the engine cannot be started, and the lower part of the curve E, that is, the area shown by diagonal lines is this area. Therefore, if a curve E' drawn above the curve E is taken as a warning level, it is possible to detect that the engine speed N is at a point on this curve E' and know that the battery capacity has decreased.

Next, FIG. 2 shows the relationship between the engine rotational speed N and the starter ON time T at the time of engine starting. In FIG. 2, F indicates the starter is in the ON state. In the figure, when the starter is turned on, the engine speed N changes and increases in stages. That is, during the time t after the starter is turned on, the engine rotational speed N increases in a quadratic manner, but eventually becomes slow and reaches a constant rotational speed N ₀ for a time Δt, and further increases as the engine starts. The constant rotation speed N ₀ shown in FIG. 2 is related to the charge capacity of the battery as shown in FIG. 1, and when the charge capacity is low, the rotation speed N ₀ also decreases in proportion to it. Therefore, by measuring the engine speed N ₀ within time Δt after t time has elapsed since the starter was turned on, the value of the charging capacity of the battery can be determined.

Based on the above measurement principle, the battery capacity display device of the present invention will be explained in detail with reference to FIG.

FIG. 3 shows a preferred embodiment of the battery capacity display device.

In the figure, a starter contact 1A is turned on by operating an ignition switch 1, and after turning on a starter contact 1A, a timer circuit 2 is driven after a time t shown in FIG. 2 has elapsed. The on time of this timer circuit 2 is set to the Δt time shown in FIG. By turning on the timer circuit 2, the excitation coil 3A of the relay 3 is excited, and its relay contact 3B is turned on. At this time, the on/off waveform 4A of the distributor point 4 as a rotation detector is shaped by the waveform shaping circuit 5 and input to the integrating circuit 6.

The output of the distributor point 4, ie, the on/off waveform 4A, has a predetermined on time and off time as shown. In waveform 4A, the shaded portion is the on time. The opening and closing of this distributor point 4 is in response to engine rotation.
By measuring the time from opening to opening again, it is possible to know the engine speed N during starter cranking.

The time from when the distributor point 4 opens until it opens again is measured by the waveform shaping circuit 5, the integrating circuit 6, and the comparing circuit 7. The output wave 5A of the waveform type circuit 5 is integrated by the integrating circuit 6, and this integrated waveform 6A is input to the comparator circuit 7. The rising edge of waveform 5A corresponds to the trailing edge of waveform 4A, and the peak value of waveform 6A is proportional to the period of waveform 5A, that is, the time from opening to opening of distributor point 4. Note that a temperature compensation circuit 16 is added to this integration circuit 6.

The integration circuit 7 is given a comparison value 8A from the comparison value setting circuit 8 in advance, and the waveform 6A is the comparison value 8A.
compared to The comparison value 8A is set to a voltage value corresponding to the engine rotational speed N ₀ corresponding to the warning level E' shown in FIG. Therefore,
The comparator circuit 7 outputs a waveform of the waveform 6A to be compared that is larger than the comparison value 8A, and its output is input to the hold circuit 9 and held.

A display lamp 10 as a display device is connected to this hold circuit 9, and the display lamp 10 is turned on by the holding output. That is, indicator lamp 1
0 is lit only when the engine speed N is below a predetermined value, that is, below the warning level E', so the charging capacity of the battery can be known by the lighting of this indicator lamp 10.

Next, a specific circuit of the above embodiment will be explained based on FIG. 4.

FIG. 4 shows a specific circuit of the battery capacity display device.

In the figure, a battery (not shown) is supplied with power to the rotating contact 1B of the ignition switch 1, and a timer circuit 2 connected to the starter contact 1A.
consists of a resistor 20 and a capacitor 21.
The excitation coil 3A of the relay 3 is connected in parallel to the capacitor 21, and the excitation coil 3A is excited after a further t time has elapsed after the ignition switch 1 is turned on to the starter contact 1A. This opens relay contact 3B.

Ignition contact 1 of ignition switch 1
A waveform shaping circuit 5, an integrating circuit 6, and a hold circuit 9 are connected to and supplied with power.

The distributor point 4 is attached to the distributor 40 and is a contact point that turns on and off as the engine rotates.
This distributor point 4 functions as a circuit element of a waveform shaping circuit 5.

The waveform shaping circuit 5 includes a transistor 50, diodes 51, 52, 53, a capacitor 54, and a resistor 5.
It consists of 5, 56, and 57. Therefore, when the distributor point 4 is turned on, since one end of the capacitor 54 is grounded, the on/off of the distributor point 4 is generated as a differential waveform voltage at the other end of the capacitor 54. In response to this voltage, transistor 50 is turned on and off when relay contact 3B is open. Then, in response to this on/off operation, an integrated waveform voltage is generated from the integrating circuit 6 at the next stage.

The integrating circuit 6 includes a transistor 60 and a diode 6.
1, a bootstrap circuit consisting of capacitors 62 and 63 and a resistor 64. Therefore, an integrated waveform voltage is generated across the resistor 64 of the integrating circuit 6 during the time when the transistor 50 in the previous stage is turned off. The peak value of this integrated waveform voltage is proportional to the off time of the transistor 50, and therefore responds to the on/off state of the distributor point 4. Note that a positive temperature coefficient thermistor 66 as the temperature compensation circuit 16 is connected to the base of the transistor 60. This thermistor 66 avoids the effects of changes in outside temperature, such as summer and winter.

The output voltage of the integrating circuit 6 is applied to the cathode of the Zener diode 70 in the comparator circuit 7. In the case of this embodiment, the comparison circuit 7 is constituted by a Zener diode 70, and also serves as the comparison value setting circuit 8. That is, the comparison value 8A is given by the Zener voltage of the Zener diode 70 itself. Therefore, when the peak value of the output voltage of the integrating circuit 6 exceeds the Zener voltage, the Zener diode 70 is turned on, and at this time the Zener current flows into the hold circuit 9 at the next stage.

The hold circuit 9 includes transistors 90, 91, a diode 92, a capacitor 93, and resistors 94, 9.
It consists of 5,96. The current from the Zener diode 70 flows into the capacitor 93, the capacitor 93 is charged by the current, and the charging voltage turns on the transistor 90. The indicator lamp 10 is turned on by this ON operation. At this time, since the transistor 91 is turned off,
A feedback circuit consisting of a resistor 94 and a diode 92 maintains the on state of transistor 90. Therefore, the indicator lamp 10 is continuously lit by the ON operation of the transistor 90, indicating that the charging capacity of the battery is at a predetermined warning level. Note that the warning level in this embodiment is set lower than the warning level E' shown in FIG. Even if a high rotational speed signal is input to the circuit, it will not cause any problem in its operation. Therefore, in this circuit, the timer circuit 2 is turned on after time t shown in FIG. 2, and in response, the relay 3 is turned on for more than time Δt.

In the embodiment described above, the distributor point 4 was used as a means for detecting the engine speed, but instead of the distributor point 4, a speed sensor was used to detect the engine speed. The display device will be explained.

A preferred embodiment is shown in FIG.

In the figure, the ignition switch 1, timer circuit 2, and relay 3 are the same as those shown in FIG. 3, and the operation and setting time of the timer circuit 2 are also the same. Therefore, after t time elapses after the starter contact 1A is turned on, the relay contact 3B is turned on by the excitation of the excitation coil 3A.

The speed sensor 11 is used in place of the distributor point 4 shown in FIG. 3, and is specifically a rotation detector consisting of an electromagnetic pickup that detects the engine rotation speed from a ring gear.

The detection output of this speed sensor 11 is input to a frequency-voltage conversion circuit 12 (hereinafter referred to as F-V conversion circuit 12), and this F-V conversion circuit 12 converts the frequency of the detection output into a corresponding voltage. be done. This voltage is applied to the capacitor 13 when the relay contact 3B is on, and this capacitor 13 is charged.

When the charging potential of this capacitor 13 is raised to a predetermined potential, the hold circuit 14 is activated and its operation is held. The output of this hold circuit 14 is displayed on a voltmeter 15 as a display device.

Therefore, the battery capacity corresponding to the engine speed is displayed on the voltmeter 15, and the battery capacity can be known from this table.

Note that the F-V conversion circuit 12 includes a temperature compensation circuit 1.
6 is added to provide temperature compensation for the outside temperature.

As explained above, although the means for detecting the engine speed is different from the circuit shown in FIG. 3, the battery capacity can be detected in the same way as the circuit shown in FIG.

Next, a specific circuit will be explained based on FIG.

FIG. 6 shows a specific circuit of a battery capacity display device having a speed sensor.

The timer circuit 2 connected to the starter contact 1A includes transistors 25, 26 and capacitors 27, 2.
8, a diode 29, and resistors 30, 31, and 32, and the collector of each transistor 25, 26 is supplied with power from the ignition contact 1B.
An excitation coil 3A of the relay 3 is connected to the collector side of the transistor 26, and a diode 34 is connected in parallel to this coil 3A.

Therefore, when the starter contact 1A is turned on, at this point the transistor 25 is turned off and the transistor 26 is turned on, so that the excitation coil 3A of the relay 3 is excited, and the relay contacts 3B ₁ and 3B ₂ are turned off. That is, the relay contacts 3B ₁ and 3B ₂ are normally closed contacts, and are turned on only when the excitation coil 3A is de-energized. After turning on the starter contact 1A, when time t shown in FIG. 2 has elapsed, the capacitor 2
The charging potential of 7 becomes a value sufficient to turn on the transistor 25, and the transistor 25 turns on. Note that the setting of the t time is determined by a time constant based on the capacitance of the capacitor 27 and the value of the resistor 30.

Then, when the transistor 25 is turned on, the base potential of the transistor 26 is lowered via the capacitor 28, and the transistor 26 is turned off. Therefore, the excitation coil 3A is in a non-excited state, and the relay contacts 3B ₁ and 3B ₂ are turned on. However, the ON time of the relay contacts 3B ₁ and 3B ₂ is only the Δt time shown in FIG. 2. This is because if the engine speed N is known within this Δt time, the battery capacity can be detected. That is, this △
The time t is given by a time constant determined by the values of the resistor 32 and the capacitor 28, and after this time has elapsed, the base potential of the transistor 26 is restored again and the transistor 26 is turned on. Therefore, relay contact 3
B ₁ and 3B ₂ are turned on for Δt time after t time elapses after the starter contact 1A is turned on.
Note that the diode 29 is for discharging the charge stored in the capacitor 27 to the ignition switch 1 and other circuits when the engine fails to start and is restarted.

The engine rotation speed N is detected by the detection output of the speed sensor 11 within this Δt time,
The battery capacity is detected from this engine speed N.

The specific circuit will be described in detail below. The engine sensor 11 is an electromagnetic pickup that detects the rotation speed of the crankshaft from the number of teeth of the ring gear that responds to the engine. FIG. 6 shows this pickup coil 110. There is. The output detected by this pickup coil 110, ie, the waveform output at point A, is an AC waveform shown in FIG. 7A. This AC waveform A is input to the F-V conversion circuit 12, where it is shaped into a predetermined waveform and then subjected to frequency-voltage conversion.

That is, the F-V conversion circuit 12 is an operational amplifier 20.
0, transistors 201, 202, 203, diodes 204, 205, 206, 207, 22
5. Capacitors 208, 209, 210, 21
1,212, resistance 213, 214, 215, 21
6,217,218,219,220,221,
It is composed of 222, 223, 224, and 226. The voltage of the AC waveform A is input to the diodes 204 and 205 through the resistor 213, and the diodes 204 and 205 constitute a limiter, so that the waveform shown in FIG. 7B is generated at point B. be done. In waveform B, +e ₁ and -e ₁ are peak values, and each forward voltage of each diode 204, 205
Determined by e ₁ . This waveform B is the capacitor 208
is input to the base of the transistor 201 via the transistor 201, and the waveform shown in FIG. A voltage having the waveform shown in FIG. 7D is generated.

This voltage having waveform D is input to operational amplifier 200 through resistor 216, which together with resistors 216, 217, and 218 constitute a Schmitt circuit, so that the voltage having waveform D is The waveform is converted, and a pulse signal shown in FIG. 7E is generated at point E.

This pulse signal E is input to the capacitor 211 via the resistor 220, and is differentiated by a differentiator circuit consisting of the capacitor 211 and the resistor 222, and a differentiated waveform shown in FIG. 7F is generated at point F. Note that the diodes 206 and 207 are for rectification, and therefore,
The differential waveform shown in FIG. 7F is half-wave rectified and has no negative waveform.

This waveform F is shaped by transistors 202, 203 and resistors 223, 224, and is formed at point G.
A pulse waveform shown in FIG. 7G is generated. The frequencies of this pulse waveform G are clearly the same by comparing waveforms G and A. The significance of converting the waveform in this way is that the output voltage detected by the speed sensor 11 is a pure AC waveform with other harmonic components superimposed on it, and it is difficult to directly measure it. The pulse waveform is used to facilitate measurement and to improve detection accuracy.

This waveform G is further connected to the diode 225.
a thermistor 16 as a temperature compensation circuit 16 including
It is integrated by an integrating circuit consisting of a resistance component of 0 and a capacitor 212, and an integrated waveform shown in FIG. 7H is generated at point H. That is, the voltage across the capacitor 212 is input to the hold circuit 14 when the relay contacts 3B ₁ and 3B ₂ are on.

The hold circuit 14 includes an operational amplifier 400, the aforementioned capacitors 13 and 401, and resistors 402 and 40.
It is composed of 3, and its composition is a filter,
When relay contacts 3B ₁ and 3B ₂ are off, it is a voltage follower circuit. Therefore, relay contact 3
When B ₁ and 3B ₂ are on, the voltage of capacitor 212 is input to capacitor 13 via resistors 402 and 403, and capacitor 13 holds this voltage. However, since the amplifier 400 constitutes a high impedance circuit, this held voltage is held even after the relay contacts 3B ₁ and 3B ₂ are turned off, and this held voltage is displayed on the voltmeter 15 as a display device. be done.

The indicated value of this voltmeter 15 corresponds to the battery capacity, and by reading this indicated value, the battery capacity can be known.

Here, the indication of this voltmeter 15 and the samister 1
Looking at the relationship with the temperature compensation function of 60, the number of rotations at which the engine cannot be started generally increases as the temperature decreases, as shown in FIG. This is due to the fact that it becomes difficult to vaporize fuel such as gasoline as the temperature decreases, and that the viscosity of engine oil increases as the temperature decreases. In Figure 1, when looking at the same rotation speed N ₂ , the temperature is
If the temperature is 20 degrees Celsius or higher, the engine can be started even after 1/4 charge, but if the temperature is 0 degrees Celsius or lower, it cannot be started, which shows that the engine speed changes depending on the temperature. Therefore, the thermistor 160 compensates for such temperature dependence by changing its resistance, and for this reason, the indication on the voltmeter 15 is compensated so that it fluctuates slightly as the temperature decreases. It is.

Note that the diode 225 is for backflow prevention.
Resistor 226 constitutes a discharge circuit for capacitor 212. Further, when the relay contacts 3B ₁ and 3B ₂ are turned on and the capacitor 13 is charged, the capacitor 212 constitutes a feedback circuit, which is for smoothing the waveform shown in FIG. 7H.

Next, the speed sensor 11 will be explained based on FIG. 8.

In the figure, speed sensor 11 is located near teeth 501 of flywheel gear 500 and is fixed to clutch housing 502. This speed sensor 11 is provided with a magnet 111,
A pickup coil 110 is wound around this magnet 111. A lead wire 112 of this pickup coil 110 is led out from behind the speed sensor 11, and its output is taken out. Therefore, the rotation of flywheel gear 500 is caused by its teeth 5.
The movement of the pickup coil 110 is detected by applying a magnetic change to the pickup coil 110, and an alternating current signal is generated at its output. This AC signal is input to the F-V conversion circuit 12 shown in FIG. 7, and its operation is as described above.

In addition, in each embodiment, a relay 3 and its relay contacts 3B, 3B ₁ , 3B ₂ are used to open and close the circuit.
However, the present invention uses such a relay contact 3.
The present invention is not limited to B, 3B ₁ and 3B ₂ , and may be constructed by a non-contact switch, a switch circuit, or other switches operated by a timer circuit.

As explained above, according to the present invention, the charging capacity of the battery, that is, the degree of deterioration can be known from the cranking speed of the engine, and since the capacity can be displayed, the capacity can be easily checked before driving. You can know. Furthermore, since the charging capacity of the battery is indirectly detected from the cranking rotation speed, the capacity can be measured without adversely affecting the battery capacity and without requiring special operations.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the engine starting rotation with respect to outside temperature, FIG. 2 is an explanatory diagram showing the engine rotation speed at the time of engine starting, and FIG. 3 is a block diagram showing an embodiment of the battery capacity display device of the present invention. 4 is a circuit diagram showing a specific circuit of the block shown in FIG. 3, FIG. 5 is a block diagram showing another embodiment of the present invention, and FIG. 6 is a circuit showing a specific circuit of the block shown in FIG. 7 is an explanatory diagram of waveforms showing the operation of the circuit shown in FIG. 6, and FIG. 8 is a partial sectional view of the speed sensor. 1... Ignition switch, 1A... Starter contact, 2... Timer circuit, 4, 11... Rotation detector, 10, 15... Display device.

Claims (1)

[Claims] 1 A timer circuit that responds to the turning on of the starter contact of the ignition switch and determines the detection time; A rotation detector that converts the engine rotation speed into an electrical signal and outputs it; A rotation that is obtained during the detection time determined by the timer circuit; A battery capacity display device comprising a display device that detects and displays battery capacity based on an output signal from a detector.