JP3000758B2 - Power supply for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for a vehicle power supply, and more particularly to a control apparatus for a vehicle power supply capable of appropriately changing a power generation voltage of a generator to improve fuel efficiency of a vehicle required for power generation.

[0002]

2. Description of the Related Art In a conventional control device for a vehicle power supply, a voltage generated by a generator is generally controlled to a constant voltage, and the voltage is controlled by a battery open terminal in order to quickly charge the battery. The voltage is determined to be higher than the voltage (for example, 12.8 V) and to a level that does not cause extreme overcharge when the battery is fully charged (for example, 14.5 V).

[0003] Japanese Utility Model Publication No. 55-52779 attempts to regenerate braking energy and improve fuel efficiency by increasing the power generation target voltage value of a regulator during vehicle deceleration.

[0004]

In the case where the power generation target voltage value is increased at the time of vehicle deceleration as described above, if the battery is fully charged, naturally, the battery cannot be charged with a large current, so that the braking energy is regenerated. May be difficult, and may overcharge and adversely affect the battery.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a vehicle power generator capable of regenerating braking energy and improving fuel efficiency without causing overcharging of a battery.

[0006]

A power generator for a vehicle according to the present invention is driven by an engine to supply power to a predetermined electric load and charge a battery, and a deceleration state detector for detecting a deceleration state of the vehicle. Means, a battery initial state detecting means for detecting an initial charge amount of the battery based on a battery starting characteristic when starting a starter for driving the engine, and a discharge amount of the battery after the starter is started. A battery capacity change detecting means for detecting, and a power generation target voltage value of the generator during the deceleration state detection until the discharge amount from when the initial charge amount is equal to or higher than a predetermined level reaches a predetermined threshold level. Power generation, wherein the power generation target voltage value is set to a first predetermined voltage and the power generation target voltage value is set to a second predetermined voltage lower than the first predetermined voltage when the deceleration state is not detected. It is characterized in that it comprises a pressure setting means.

In a preferred aspect, the power generation voltage setting means determines whether the deceleration state is not detected until the discharge amount from when the initial charge amount is equal to or higher than a predetermined level reaches a predetermined threshold level. The power generation target voltage value of the generator is set to the second predetermined voltage, and when the initial charge amount is not equal to or higher than a predetermined level, and when the initial charge amount is equal to or higher than a predetermined level, and the discharge amount is equal to a predetermined threshold. When the value level is reached, the power generation target voltage value is set to a third predetermined voltage higher than the second predetermined voltage and lower than the first predetermined voltage.

The above-mentioned initial charge and discharge amounts of the battery may be directly detected as capacity or may be estimated based on other parameters having a correlation with these initial charge and discharge amounts. The power generation voltage setting means is configured to control the power generation target during at least a part of a deceleration state detection period until the discharge amount reaches a predetermined threshold level when the initial charge amount is equal to or higher than a predetermined level. As long as the voltage value is set to the first predetermined voltage, the power generation target voltage value is set to be smaller than the first predetermined voltage in at least a part of the period in which the deceleration state is not detected. What is necessary is just to set to a low 2nd predetermined voltage.

In a preferred embodiment, when the initial charge amount has not reached the predetermined level, and when the initial charge amount has reached the predetermined level but the subsequent discharge amount has exceeded the predetermined level, the battery In order to prevent over-discharge of the power generation, the power generation voltage is set to the third power generation target voltage value corresponding to the conventional power generation voltage (for example, 14.5 V). In a preferred aspect, the second predetermined voltage is equal to or higher than a terminal opening voltage calculated from an electrolyte specific gravity when the battery is fully charged.

[0010] In a preferred aspect, the battery initial state detecting means obtains the initial charge amount based on at least a battery voltage value and a battery discharge current value at the time of starting the starter. In a preferred aspect, the battery initial state detecting means obtains the initial charge amount based on at least the engine speed during starter startup.

[0011] In a preferred aspect, the battery capacity change detecting means determines the amount of battery discharge based on at least the amount of charge / discharge current of the battery current after the engine is started. In a preferred aspect, the battery capacity change detecting means is obtained from the accumulated time during which the conductivity of the semiconductor switch that controls the exciting current of the generator is equal to or more than a predetermined value.

[0012]

The battery initial state detecting means detects the initial charge amount of the battery based on the battery starting characteristic when starting the starter, the deceleration state detecting means detects the deceleration state of the vehicle, and the battery capacity change detecting means. Detects the amount of battery discharge after the starter is started.

The power generation voltage setting means sets the initial charge amount to a predetermined level (for example, a capacity sufficient to restart the starter).
In this case, the target power generation target voltage value of the generator is set to a first predetermined value when the deceleration state is detected until the discharge amount decreases to a predetermined threshold level (for example, a level at which it is determined that it is better to charge the battery immediately). Voltage (for example, 15V)
In addition, when the above-described deceleration state is not detected, the power generation target voltage value is set to a second predetermined voltage (for example, 13 V) lower than the first predetermined voltage.

In other words, in the state other than the deceleration state, the amount of power generation is reduced to suppress charging of the battery, and in the state of deceleration, the amount of power generation is increased to increase the battery charge.

[0015]

As described above, the vehicle power generating apparatus according to the present invention has a power generation target of the generator when detecting the deceleration state until the discharge amount reaches the predetermined threshold level when the initial charge amount is equal to or higher than the predetermined level. A power generation voltage setting means for setting the voltage value to the first predetermined voltage and setting the power generation target voltage value to the second predetermined voltage lower than the first predetermined voltage when the deceleration state is not detected, A vehicle power generation device capable of recovering braking energy during deceleration to improve fuel efficiency and preventing overcharging, and capable of regenerating braking energy and improving fuel efficiency without causing overcharging of a battery. Can be.

Further, when the battery is near full charge during the deceleration, the battery is discharged by the polarization action inside the battery during the power generation voltage drop period immediately after the deceleration. The required power generation amount can be reduced, and the fuel efficiency improvement effect can be further improved.

[0017]

FIG. 1 is a block diagram showing one embodiment of a vehicular power generating apparatus according to the present invention. This device includes a generator 2 driven by an engine to supply power to a predetermined electric load and charge a battery, and a controller 7 for designating a power generation target voltage of the generator 2.

More specifically, the generator 2, which is a three-phase AC generator, includes a three-phase armature winding 21 and a three-phase full-wave rectifier 23 for rectifying each generated voltage of the three-phase armature winding 21. Has a field coil 22 having one end connected to the higher end of a three-phase full-wave rectifier 23, and a regulator 24, and is usually called an alternator. The high-order end of the three-phase full-wave rectifier 23 is connected to the high-order end of the battery 1 through the current sensor 6 for detecting the battery charge / discharge current, and the low-order end of the three-phase full-wave rectifier 23 and the low-order end of the battery 1 are grounded. .

The regulator 24 is composed of a power transistor 24a and a comparator 24b for controlling the base voltage of the power transistor 24a. The other end of the field coil 22 is connected to a grounded emitter. Transistor 2
4a. Comparator 24b
The terminal voltage of the battery 1 is divided and inputted to a minus input terminal of the battery, and a power generation target voltage value is inputted from the controller 7 to a plus input terminal thereof.

The comparator 24b compares the power generation target voltage Vp from the D / A converter 72, which will be described later, with the divided voltage VF of the battery 1, and controls the power transistor 24a to switch the power generation voltage. As a result, the power generation voltage is made to follow the power generation target voltage value Vp. The controller 7 comprises a microcomputer device 70 and an A / D converter 71
And a D / A converter 72, and constitute the battery initial state detecting means, the deceleration state detecting means, the battery capacity change detecting means, and the power generation voltage setting means in the present invention.

The microcomputer device 70 includes an I / O port 73,
A CPU 74, a RAM 75, and a ROM 76 are provided. More specifically, the A / D converter 71 A / D converts the battery terminal voltage and the battery charge / discharge current detected by the current sensor 6 and inputs them to the I / O port 73.
The A-converter 72 D / A-converts the power generation target voltage value output from the controller and inputs it to the + voltage input terminal of the comparator 32.

Reference numeral 5 denotes an electric load of the vehicle, which is supplied with power from the battery 1 through the switch 50. Reference numeral 3 denotes an engine, which is started by the starter 4 and drives the generator 2. The starter 4 is supplied with power from the battery 1 through the current sensor 6. The battery 1 is a lead battery using sulfuric acid as an electrolytic solution, and the terminal open voltage of a rated 12 V battery in a fully charged state and a stable state is about 1
2.8V. This terminal open voltage is proportional to the specific gravity of the electrolytic solution, that is, the charged state of the battery in a stable state where the battery is left without charging / discharging, and has the characteristics shown in FIG. The terminal open voltage has a characteristic that is higher immediately after charging and lower immediately after discharging than the characteristic in FIG. 2 due to the polarization action of the battery immediately after charging and discharging.

Hereinafter, various operations executed by the controller 7 will be described with reference to flowcharts. (Deceleration state detection subroutine) Hereinafter, a deceleration state detection subroutine constituting the deceleration state detection means according to the present invention will be described with reference to FIG.

First, the throttle opening is read by a throttle signal from a throttle opening sensor (not shown) provided coaxially with the throttle lever, and the vehicle speed is read by a vehicle speed sensor (not shown) connected to the axle. (20
0), and check whether the throttle opening is fully closed (20).
2) If not fully closed, proceed to step 208 to determine the non-deceleration state; if not fully closed, check whether the vehicle speed is 5 km or more (204). If not 5km, proceed to step 204 to enter the non-deceleration state. If it is 5 km or more, the routine proceeds to step 206, where it is determined that the vehicle is decelerating.

That is, when the throttle is fully closed and the vehicle speed is 5 km or more, it is considered that the vehicle is in a deceleration state, and the flag R is set to 1. Otherwise, it is determined that the vehicle is not in a deceleration state and the flag R is set to 0, and the routine is terminated. I do. (Battery Initial State Detection Subroutine) Hereinafter, the battery initial state detection subroutine constituting the battery initial state detection means according to the present invention will be described with reference to FIG.

[0026] The subroutine - Chin Star - starting i.e. key of motor 4 - other switches (not shown) - initiated by N'on, first reads the current I _B of the current sensor 6 (10
0), and waits until the current I _B is equal to or greater than 100A (10
2) Star If a more 100A - Star a timer set to 3 seconds as the data start start - reports open (104), reads the current I _B and the battery voltage V _B (106).

Next, it is checked whether or not the timer indicates that 3 seconds have elapsed (110).
Advances to 8, elapsed current unless I _B is examined whether 150A (112), 150A unless Step 1
16 at a current I _B is returned to step 106 if not reduced by examining whether drops below 60A.
Also, if 150A stores the battery voltage V _B read in step 106 in the memory (114), Rita to step 106 - the main routine.

[0028] Thus, after the current I _B becomes 100A, in the period until reduced to or 60A to three seconds, the last 10 of the battery voltage V _B is the memory point of the current I _B is 150A Is stored in Next, the average value of these 10 battery voltages V _B is calculated (11
8), the average battery voltage V _B m the calculated is examined whether greater than a predetermined level) A means at a predetermined threshold voltage (the invention (120), sufficiently Star larger - are the data restartable It is determined that the battery initial state is good, that is, the initial charge amount is sufficient, and the flag S is set to 1. Otherwise, it is determined that the battery initial state is bad, that is, the initial charge amount is insufficient, the flag S is set to 0, and the routine ends. (Battery Capacity Change Detection Subroutine) Hereinafter, the battery capacity change detection subroutine constituting the battery capacity change detection means according to the present invention will be described with reference to FIG.

This subroutine is also started when the starter 4 is started, that is, when a key switch (not shown) is turned on. First, in step 302, the accumulated value is accumulated in a built-in accumulator (not shown). after resetting the integrated value .SIGMA.I _B of the current I _B were to read the current I _B (304), the integrated value .SIGMA.I _B read I _B this was added to (this time 0) (306), the integrated value .SIGMA.I _B That is, it is determined whether or not the total discharge current is equal to or higher than the predetermined threshold level B (30).
8) If it is equal to or higher than the predetermined threshold level B, it is determined that the discharge amount has reached the predetermined threshold level, and the flag ΔS is set to 0.
(310), and if the predetermined threshold level B has not been reached, the flag .DELTA.S is set to indicate that the main charge of the present embodiment is the large charge at deceleration and the small charge at non-deceleration. It is set to 1 (310). Rita Step 304 - until down to the integrated value .SIGMA.I _B is equal to or greater than a predetermined threshold level B The subroutine - repeated routine. (Generation voltage setting subroutine) Hereinafter, the generation voltage setting subroutine constituting the generation voltage setting means according to the present invention will be described with reference to FIG.

This subroutine is also started when the starter 4 is started, that is, when a key switch (not shown) is turned on. First, at step 400, the flags R, S, .DELTA.
In addition to reading S, the operation state of a specific electric load (for example, headlight, indoor blower, etc.) in which the battery voltage fluctuation is not preferable is read, and the flag E is set to 1 when the specific electric load is on, and the flag E Is set to 0 (400).

Next, it is checked whether the flag S is 1, the flag ΔS is 1, the flag R is 1, and the flag E is 0 (402).
If Yes, the initial charge amount is equal to or higher than the predetermined level, the discharge amount (accumulated discharge amount) has not reached the predetermined threshold level, the deceleration state is being detected, and the electric load that dislikes battery voltage fluctuation is turned on. As a result, the power generation target voltage value Vp is raised to 15 V (the first predetermined voltage in the present invention) (410), and then the power generation target voltage value Vp is raised to the D / A converter.
Then, the battery charge current is increased to perform regenerative braking (412).

If the determination result in step 402 is No, it is checked whether the flag S is 1, the flag ΔS is 1, the flag R is 0, and the flag E is 0 (404). It is assumed that the discharge amount (accumulated discharge amount) is equal to or higher than the predetermined level, the discharge amount (accumulated discharge amount) has not reached the predetermined threshold level, the deceleration state is not being detected, and the electric load that dislikes battery voltage fluctuation is not turned on. Value Vp is 13
V (the second predetermined voltage in the present invention) (40
8) Then, the power generation target voltage value Vp is set to the D / A converter 72.
(412), the battery charging current is reduced, and the battery 1 is maintained in a large chargeable state.

If the determination result in step 404 is No, the power generation target voltage value Vp is set to the normal 14.5 V (the third predetermined voltage in the present invention) (406), and the above-described fuel efficiency improving operation is performed. I refrain from doing it. With this configuration, since the generated voltage is reduced to 13 V at the end of the deceleration state, the electromotive voltage generated by charging the battery 1 during deceleration and generated by the polarization action inside the battery can be used for discharging, and fuel consumption can be reduced. Can be improved.

Further, when it is detected that the electric load which does not want to fluctuate the battery voltage is turned on, the power generation target voltage value Vp is set to the normal voltage, so that the electric load (headlight, indoor blower, etc.) due to the change of the power generation voltage is applied. Adverse effects can be avoided. Also, since the initial charge amount is detected at the start of the starter, the battery charge amount can be accurately detected, and when the discharge amount (cumulative discharge amount) reaches a predetermined threshold level, the power generation target Since the voltage value Vp is the normal voltage, it is possible to avoid an adverse effect on the restart of the starter.

The battery initial state detecting means is a starter.
Any method can be used as long as it is possible to determine whether there is sufficient power to restart the starter, and it is also possible to determine from the engine speed during starter start. Further, the battery capacity change detecting means only needs to detect the discharge amount of the battery 1,
It can also be determined from the operation state of the switching transistor 24a.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment;

FIG. 2 is a graph showing the relationship between electrolyte specific gravity of a battery and terminal open voltage;

FIG. 3 is a flowchart showing a deceleration state detection subroutine.
To

FIG. 4 is a flowchart showing a subroutine for detecting a battery initial state;

FIG. 5 is a flowchart showing a subroutine for detecting a change in battery capacity;

FIG. 6 is a flowchart showing a generated voltage setting subroutine.
To

FIG. 7 is a diagram corresponding to a claim;

[Explanation of symbols]

 1 is a battery, 2 is a generator, 7 is a controller

Claims (2)

(57) [Claims] A generator driven by an engine for supplying power to a predetermined electric load and charging a battery, a deceleration state detecting means for detecting a deceleration state of the vehicle, and starting a starter for driving the engine. Battery initial state detection means for detecting the initial charge amount of the battery based on the battery start characteristic at the time, battery capacity change detection means for detecting the discharge amount of the battery after starter start, and the initial charge amount Setting the power generation target voltage value of the generator to a first predetermined voltage during the detection of the deceleration state until the discharge amount from when the discharge amount is equal to or higher than a predetermined level reaches a predetermined threshold level, and A power generation voltage setting means for setting the power generation target voltage value to a second predetermined voltage lower than the first predetermined voltage when no is detected. Dual-use power generator. 2. The generator voltage setting means according to claim 1, wherein said deceleration state is not detected until said discharge amount from when said initial charge amount is equal to or higher than a predetermined level reaches a predetermined threshold level. The power generation target voltage value is set to the second predetermined voltage, and if the initial charge amount is not equal to or higher than a predetermined level, and if the initial charge amount is equal to or higher than a predetermined level and the discharge amount reaches a predetermined threshold level. 2. The vehicle power generation device according to claim 1, wherein, in such a case, the power generation target voltage value is set to a third predetermined voltage higher than the second predetermined voltage and lower than the first predetermined voltage.