JPH06296332A - Electric power controller for motor vehicle - Google Patents

Abstract

PURPOSE:To provide an electric power controller for a motor vehicle capable of maintaining small voltage fluctuation in main battery means, of eliminating overcharging or overdischarge and also of efficiently storing regenerative power during deceleration by temporarily storing regenerative power during deceleration in standby battery means and releasing it except a deceleration time. CONSTITUTION:Regenerative power produced by an alternator 3 through traveling engine 8 rotated by tires 9 during deceleration is temporarily stored in standby battery means 7. And the power charged to the standby battery means 7 is supplied to a vehicle electric load 2 in preference to main battery means 1 during driving by acceleration, constant speed driving and idling except the deceleration of a motor vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes the kinetic energy of a vehicle during deceleration to regenerate the electric power generated by a vehicle generator to a preliminary power storage means, and extracts the power from the preliminary power storage means except during deceleration. Thus, the present invention relates to a vehicle power control device that reduces the amount of power generated by the vehicle generator except during deceleration to improve fuel efficiency.

[0002]

2. Description of the Related Art Since a vehicle generator is connected to an engine and its rotation speed changes over a wide range, a regulator for controlling a generated voltage to a predetermined value is provided. The regulator normally turns on and off the field current of the vehicle generator.
Then, the power generation voltage is controlled by intermittently generating power from the power generator, and when the load on the power generator increases, the power generation time is lengthened in order to maintain the power generation voltage constant. By the way, in recent years, the electrical components of vehicles have rapidly increased, and along with this, the size of vehicle generators has also increased. A large-capacity vehicle generator imposes a heavy load on the engine during power generation, impairing the acceleration performance of the vehicle. On the other hand, when the vehicle is decelerating, it is preferable to positively generate electric power to accelerate the braking of the engine and regenerate the energy that is wastefully dissipated to the battery. However, the usage of electrical components fluctuates day or night or depending on the season.If the power generation time is forcibly shortened for acceleration, the so-called generator, which uses many electrical components, has a large battery load. It causes discharge and flickering of the lamp. On the other hand, if no electric components are used and the load of the generator is small and the power generation time is forcibly lengthened during deceleration, the battery may be overcharged or the lamp may run out. Therefore, shorten the power generation time only when the vehicle is accelerating and the load on the generator is small,
It is desired to realize a regulator that prolongs the power generation time only when the vehicle is decelerating and the load of the generator is large. Japanese Patent Laid-Open No. 59-106900 detects the acceleration state of a vehicle by the amount of change in the number of revolutions of a generator and the load state of the generator by the conduction rate of a switching element that controls the field winding current. An object of the present invention is to provide a regulator that appropriately controls a power generation time by generating a set value of a generator output voltage according to a running state of a vehicle and a load state of a generator.

[0003]

However, when the vehicle is decelerating and the load is large, the regenerative electric power is stored in the battery by raising the set voltage of the regulator, and when the vehicle is accelerating and the load is small, the set voltage is kept constant. In a vehicle generator control device that reduces the load on the generator by reducing the output of the vehicle generator to improve fuel efficiency, the battery voltage fluctuates greatly, and the set voltage is reduced when the generator load is small. If the power is raised, the main storage means will run out of liquid and the lamp will burn out due to overcharging. On the other hand, if the set voltage is lowered by accelerating with a large generator load,
A flicker phenomenon occurs in the lamp due to an increase in voltage fluctuation due to over-discharge of the battery and a decrease in regulator ON time. Further, the fully charged main power storage means has a low power density during charging, and therefore cannot efficiently store regenerative power during deceleration. The present invention has been made to solve the above problems, and a main power storage unit is provided by providing a spare power storage unit to temporarily store regenerative electric power in the spare power storage unit at the time of deceleration and release the regenerated power at times other than deceleration. It is an object of the present invention to provide a power control device for a vehicle, which has a small voltage fluctuation, is free from overcharge and overdischarge, and can efficiently store regenerative power during deceleration.

[0004]

As a concrete means for solving the above problems, the present invention provides a vehicle power source including a vehicle generator driven by a running engine and a main power storage means, and a spare power storage means. A DC-DC converter which is bidirectionally switchable and connectable between the vehicle power source and the reserve power storage means and bidirectionally voltage convertible; The DC means for charging the means, discharging the charged electric power in preference to the main power storage means, and supplying the electric power to the vehicle electrical load except during deceleration.
An electric power control device for a vehicle is provided, which comprises: an electronic arithmetic unit that controls switching of a DC converter.

[0005]

According to the vehicle power control device having the above structure, the DC-DC converter is switch-controlled by the electronic arithmetic unit so that the regenerative power obtained during deceleration is stored in the auxiliary power storage means. In addition, during acceleration other than deceleration, during constant speed running, during idling, etc., the electric power charged in the auxiliary power storage means is supplied to the vehicle electrical load with priority over the main power storage means, and in other cases. The electric power is supplied to the vehicle electrical load by the generator and the main power storage means, and the electric power by the generator is stored in the main power storage means.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle power control device of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a vehicle power control device. The battery 1 forming the main power storage means charges the electric power generated by the alternator 3 forming the vehicle generator and discharges it to the vehicle electric load 2. In addition, when the power generation voltage of the alternator 3 is lower than the charging voltage of the battery 1 as when the engine 8 is stopped and started, the battery 1 supplies the electric load 2 with the power generated by the chemical action of the battery 1 itself. The voltage of the alternator 3 when the battery 1 can be charged is usually 13V to 15V. Inside the alternator 3, a regulator and a rectifier (not shown) are built in, and the regulator turns ON / OFF the field current flowing through the rotor of the alternator 3 to supply 13V to the stator.
A three-phase AC voltage of 15V is generated, and the rectifier rectifies the AC voltage of the stator into DC. The electric load 2 is an electric device that consumes electric power, such as various lamps such as a headlight, a hazard lamp, and a flasher, and various devices such as a starter, an air conditioner, a wiper, and a radio. The alternator 3 is connected to the engine 8 and is driven by the engine 8 when idling, accelerating and traveling at a constant speed, but the throttle valve is fully closed when the vehicle is decelerating. Driven through.

The DC-DC converter 4 is a device for switching and controlling the charging and discharging of the electric double layer capacitor 7 which constitutes the preliminary storage means, and is, for example, a DC / AC exchanger on the low voltage side, a transformer, and a rectifier. , A one-way diode, and a switching electronic switch, and the electronic switch is switched by the ECU 5 forming an electronic arithmetic unit to charge and discharge the auxiliary power storage means 7. E
The CU 5 performs calculation when idling, acceleration, constant speed traveling, deceleration, engine 8 stop, and the voltage signal of the battery 1 are detected at the signal receiving terminal 6. Then, the switching control signal is sent to the DC-DC converter 4 based on the calculation result. The electric double layer capacitor (hereinafter referred to as the electric double layer capacitor 7) forming the preliminary storage means 7 is a capacitor that uses an electric double layer generated at the interface between a solid and a liquid, and uses activated carbon having a large surface area per unit volume as the solid. The capacity is increased by using dilute sulfuric acid as the liquid. Therefore, the capacity is several thousand times or more that of a general capacitor, which is a large capacity. And DC-DC
The converter 4 performs switching control to charge regenerative electric power or supply electric power to the vehicle electric load 2.

An outline of the operation of the vehicle power control device having the above configuration will be described first. When the ECU 5 detects the deceleration traveling by the input signal to the signal receiving terminal 6, the ECU 5 detects whether the battery voltage (Vbat) of the battery 1 is at a constant level (for example, 13V). When the battery voltage is above a certain level, the DC-DC converter 4 is controlled to charge the electric double layer capacitor 7 with a constant current up to its withstand voltage level. In addition, during acceleration of the vehicle other than during deceleration, during constant speed driving, and during idling, the ECU
Reference numeral 5 controls the DC-DC converter 4 to discharge the electric double layer capacitor 7 so as to supply the vehicle electric load 2 with a current of about 10 A required for the regular electric load of the vehicle. In this case, the electric double layer capacitor 7 is not discharged so that the battery 1 is not overcharged, for example, when the battery voltage is 15 V or higher.

Next, the operation of the vehicle power control device having the above-mentioned configuration will be described with reference to the flowchart shown in FIG. FIG. 2 shows the main program P1 in the ECU 5.
10 is a flowchart showing 00. When the engine is started, the alternator 3 continues to output a constant voltage under the control of the regulator. Then, in step S110, it is determined by the input signal of the signal receiving terminal 6 whether or not it is in the idling state. If it is in the idling state, in step S111, if the battery voltage is 15 V or less, the DC-DC converter. 4 is switched and the electric current of about 10 A required for the regular electric load of the vehicle is supplied from the electric double layer capacitor 7 to the vehicle electric load 2. When the battery voltage exceeds 15V, electric double layer capacitor 7 does not discharge so that battery 1 is not overcharged, so that electric power is supplied to vehicle electric load 2 by alternator 3 or battery 1. Then, during acceleration traveling (steps S120 to S121) and during constant speed traveling (step S).
Also in 130 to S131), the determination and the processing according to the battery voltage similar to those in the idling state (steps S110 to S111) are performed. And step S
When the deceleration traveling is confirmed by the input signal of the signal receiving terminal 6 in 140, the electric double layer capacitor 7 is charged to the withstand voltage by the DC-DC converter 4 when the battery voltage is 13 V or more in step S141.
Further, in step S141, the battery voltage is 13V.
When it is less than, the battery 1 is charged. Next, in step S150, it is determined whether the engine is stopped, and if it is not stopped, step S110
If it is stopped, the program ends in step S160.

According to the above embodiment, by controlling the charging / discharging of the electric double layer capacitor 7 as described above, the power generation amount of the alternator 3 exceeds the power consumption amount of the vehicle electric load 2 when the battery 1 is full. It should be noted that excess power that cannot be regenerated by the battery 1 can be used when the battery 1 is not in a full state and the amount of power generated by the alternator 3 is insufficient, so that power is not wasted and power generation by the alternator 3 is eliminated. The fuel consumption of the engine can be improved by reducing the amount. Further, since the regulated voltage of the regulator is always constant regardless of the traveling state, unlike the method of charging the battery 1 by significantly increasing the regulated voltage of the regulator during decelerating traveling, the voltage fluctuation of the battery 1 is small and the lamps There is no flicker. Further, since the number of times of charging / discharging the main power storage means can be reduced, the life of the main power storage means can be extended.

The DC-DC converter 4 and the ECU
If the vehicle 5 and the electric double layer capacitor 7 are combined into one package and the vehicle deceleration signal is detected by the brake lamp, the vehicle can be easily mounted even on a vehicle that has already been sold and is on the market. Furthermore, in vehicles that use injection to perform fuel cut during deceleration, if the deceleration signal is detected from the fuel cut signal,
Only during deceleration traveling can be detected more accurately, and electric power can be regenerated more effectively.

Next, as another embodiment, an embodiment in which the present invention is applied for the purpose of suppressing the rotation fluctuation caused by the repetition of combustion and compression of the engine at idling,
A description will be given based on the flowchart. Since the rotation of the engine is repeatedly accelerated in the combustion stroke and decelerated in the compression stroke, there is a rotation fluctuation of about several tens rpm even during idling. This fluctuation in rotation during idling causes the lamps to flicker and the tachometer pointer to quiver. In addition, since irregular vibrations are given to the passengers and the passengers feel uncomfortable, it is important to suppress the rotational fluctuation during idling in order to improve the quality of the vehicle. FIG. 3 is a flowchart showing a program P200 for controlling this rotation fluctuation. When the increase tendency of the engine speed due to combustion is detected in step S210, D is detected in step S211.
The C-DC converter 4 is switch-controlled to charge the electric double layer capacitor 7. Therefore, the electric double layer capacitor 7
By supplying electric power to the engine, the electric load of the alternator 3 is increased, and the increase in engine speed can be suppressed. In addition, when the decrease tendency of the engine speed due to compression is detected in step S220,
On the contrary, in step S221, the DC-DC converter 4 is switch-controlled to supply the electric power of the electric double layer capacitor 7 to the vehicle electric load 2. Therefore, it is possible to reduce the electric load on the alternator 3 and suppress the reduction in the engine speed. By repeating the above-described two operations, it is possible to suppress fluctuations in rotation during idling and stabilize the rotation. Therefore, it is possible to eliminate the fluctuation of the output voltage of the alternator 3, which is caused by the fluctuation of the rotation, the flicker of the lamps, and the unpleasant engine vibration.

Further, an embodiment to which the present invention is applied to suppress the fluctuation of the engine speed due to the use of an intermittent electric load such as a hazard and stabilize the engine rotation will be described with reference to a flow chart P300 shown in FIG. If an intermittent electric load such as a hazard is used when idling,
The engine speed is 50 due to the load change of the alternator 3.
It fluctuates about rpm. In that case, when it is detected that the intermittent electric load is ON (hazard or the like is lit) in step S310, a part of the electric power required by the intermittent electric load is switched to the DC-DC converter 4 in step S311, and the electric double layer capacitor 7 is switched. By supplying the power, the load originally applied to the alternator 3 is supplemented. Also, step S3
When it is detected that the intermittent electric load is OFF (a hazard or the like is off) at 20, the DC-DC converter 4 is switched to store the electric power consumed by the intermittent electric load in the electric double layer capacitor 7. By repeating the above two operations, the electric load of the alternator 1 can be made constant when the intermittent electric load is used, and the rotation fluctuation of the engine can be suppressed and the rotation can be stabilized. Therefore, as in the case of suppressing the rotation fluctuation caused by the repetition of combustion and compression described above, the pulsation due to the intermittent electric load of the output voltage of the alternator 3 caused by the rotation fluctuation disappears, and the flicker of the lamps during the intermittent load use, the meter There is an effect that panel flicker and unpleasant engine vibration can be eliminated.

[0014]

The electric power control apparatus for a vehicle of the present invention has the above-mentioned configuration, and by providing the preliminary power storage means, the regenerative power at the time of deceleration is temporarily stored in the preliminary power storage means and is discharged at times other than during deceleration. As a result, the voltage fluctuation of the main power storage means is small, there is no overcharge or overdischarge, and regenerative power during deceleration can be efficiently stored.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an overall configuration of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 3 is a flowchart showing an embodiment in which the present invention is applied to stabilization of the engine speed during idling.

FIG. 4 is a flow chart showing an embodiment in which the present invention is applied to voltage stabilization when using an intermittent electric load during idling.

[Explanation of symbols]

1 ... Main power storage means (battery), 2 ... Vehicle electric load,
3 ... Vehicle generator (alternator), 4 ... DC
-DC converter, 5 ... Electronic processing unit (ECU),
6 ... Signal receiving terminal, 7 ... Spare storage means (electric double layer capacitor), 8 ... Engine, 9 ... Tire, P100-P300 ... Program, S110
~ S340 ... Step

Claims (1)

[Claims] 1. A vehicle power source including a vehicle generator driven by a running engine and a main power storage unit, a backup power storage unit, and a bidirectional switch connected between the vehicle power supply and the backup power storage unit. A DC-DC converter that is connectable and capable of voltage conversion, detects the running state of the vehicle, charges the auxiliary power storage unit during deceleration, and discharges the charged power in preference to the main power storage unit except during deceleration. An electric power control device for a vehicle, comprising: an electronic arithmetic unit that controls switching of the DC-DC converter so that the electric power is supplied to an electric load of the vehicle.