JP2003148310A - Engine starting power source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine starting power source device capable of compensating for a voltage drop in a battery by a small capacitor upon starting an engine. SOLUTION: This system has the capacitor 2 for compensating for the voltage drop in the battery 1 when restarting an engine. The capacitor 2 is used when starting a starter 5, and is arranged in a charging circuit for charging the capacitor 2 with the battery 1 and a discharge circuit for impressing capacitor voltage on the starter 5 by adding the capacitor voltage obtained by electric charge stored in the capacitor 2 to battery voltage. The charging circuit and the discharge circuit can be selectively switched by a switching relay 11 controlled by an ECU 4. Thus, the capacitor 2 is charged by selecting the charging circuit at time except for engine starting time, and is switched to the discharge circuit at engine starting time. The capacitor voltage is added to the battery voltage, and is impressed on the starter 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine starting power supply device that uses a battery and a capacitor together.

[0002]

2. Description of the Related Art Conventionally, when starting an engine of a vehicle,
Since the starting current of the starter is large, there is a problem that the voltage drop of the battery becomes large and the operation of the starter is affected (for example, the starting time becomes long). Also, for example, in a vehicle equipped with an eco-run system (also called an idle stop system) that automatically stops the engine when temporarily stopped at an intersection or the like, when the engine is restarted, the voltage drop of the battery causes It may also affect the operation of the installed electric equipment (for example, an accessory equipment such as a navigator or an audio equipment). On the other hand, measures such as securing a power supply (capacitor) dedicated to the starter separately from the battery or setting a backup power supply (capacitor) for each electric device have been adopted.

[0003]

However, even if a power source dedicated to the starter is provided or a backup power source is set for each electric device, the capacity of one capacitor is small, so that the starter and the electric device are rated. In order to secure the voltage, it is necessary to connect a plurality of capacitors (capacitor becomes large). In this case, there is a problem in that not only the control circuit becomes complicated because the connected individual capacitors are evenly filled, but also the cost increases. The present invention has been made based on the above circumstances, and an object thereof is to provide an engine starting power supply device capable of compensating for a voltage drop of a battery at the time of engine starting with a small capacitor.

[0004]

(Invention of Claim 1) The present invention relates to a charging circuit for storing charges in a capacitor by a battery voltage, and a discharging circuit for applying the voltage of the charged capacitor to a load in addition to the battery voltage. And a circuit switching means for switching from a charging circuit to a discharging circuit at the time of starting the engine, wherein the charging circuit includes a first resistor that limits a charging current of the capacitor in series with the battery. Is connected to the battery in parallel with the capacitor, and the capacitor can generate a capacitor voltage sufficient to compensate for the voltage drop of the battery at the time of engine start. It has a capacity and is charged according to the voltage division ratio of the first resistance and the second resistance.

According to this structure, the voltage drop of the battery can be compensated by applying the capacitor voltage to the load in addition to the battery voltage when the engine is started. Further, since it is sufficient for the capacitor voltage to be able to compensate for the voltage drop of the battery at the time of starting the engine, it is not necessary to increase the capacity of the capacitor more than necessary or to connect a plurality of capacitors, and it is possible to reduce the size of the capacitor (for example, 1 Individual capacitors are sufficient).

(Invention of Claim 2) In the engine starting power supply device according to claim 1, the engine is automatically stopped when a predetermined stop condition is satisfied after the engine is started, and then the predetermined start condition is satisfied. It is used in vehicles equipped with an eco-run system that automatically starts the engine when it is operated, and the circuit switching means is composed of a switching relay for selectively switching between the charging circuit and the discharging circuit and a control circuit for controlling the operation of this switching relay. The control circuit is configured to control the switching relay to switch from the charging circuit to the discharging circuit when the engine is restarted by the eco-run system.

(Invention of claim 3) In the engine starting power supply device according to claim 2, the control circuit prohibits the automatic stop of the engine by the eco-run system until a predetermined amount of charge is stored in the capacitor. If the eco-run system is made to function in the state where the capacitor does not store a predetermined charge, the voltage drop of the battery cannot be compensated by the capacitor voltage when the engine is restarted. Therefore, by prohibiting the automatic stop of the engine by the eco-run system until the electric charge necessary to compensate for the voltage drop of the battery at the time of engine start is stored in the capacitor, the voltage of the battery for the operation of the starter or the operation of electrical equipment The effect of descent can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a circuit configuration diagram of an engine starting power supply device. This system is installed in a vehicle having an eco-run system that automatically stops the engine when it is temporarily stopped at an intersection or a traffic jam, for example. When the engine is temporarily stopped and then restarted, the voltage drop of the battery 1 is removed. A first capacitor 2 and a second capacitor 3 for supplementary auxiliary power supply, and an ECU 4 for controlling the eco-run system are provided.

The first capacitor 2 is used when starting the starter 5, and is stored in the first charging circuit for charging the first capacitor 2 with the battery 1 and the first capacitor 2. It is provided in the first discharge circuit that applies the capacitor voltage obtained by the generated charge to the starter 5 in addition to the battery voltage. Second capacitor 3
Is used as an auxiliary power source for maintaining the operation of the electric device 6 (for example, an accessory device such as a navigator or an audio device), and a second charging circuit for charging the second capacitor 3 with the battery 1. , A second discharge circuit that applies the capacitor voltage obtained by the charge accumulated in the second capacitor 3 to the battery voltage and applies the voltage to the electric device 6.

The first charging circuit connects a resistor 7 for limiting the charging current of the first capacitor 2 to the battery 1 in series with the first capacitor 2 and divides the battery voltage. A resistor 8 is connected to the battery 1 in parallel with the first capacitor 2, and the resistor 7 and the resistor 8 are connected.
The first capacitor 2 is charged according to the voltage division ratio of The first discharge circuit includes a battery 1 and a first discharge circuit for the starter 5.
Is connected in series with the capacitor 2, and the motor contact 10 of the electromagnetic switch 9 provided in the starter 5 is turned on,
And the first switching relay 11 is turned on (relay coil 11
It is closed by energizing a and turning on the relay switch 11b to the ON terminal 11c).

The second charging circuit connects a resistor 12 for limiting the charging current of the second capacitor 3 to the battery 1 in series with the second capacitor 3 and divides the battery voltage. Second resistor 13 to battery 1
The capacitor 3 is connected in parallel with the capacitor 3 and charges the second capacitor 3 in accordance with the voltage division ratio of the resistors 12 and 13. The second discharge circuit is configured by connecting the battery 1 and the second capacitor 3 in series to the electric device 6,
It is closed by turning on the second switching relay 14 (energizing the relay coil 14a and turning on the relay switch 14b to the ON terminal 14c).

In the first charging circuit and the second charging circuit, the electric charge stored in the first capacitor 2 and the second capacitor 3 is a value capable of compensating for the voltage drop of the battery 1 when the engine is started. The respective partial pressure ratios are set so that

Next, the operation of this embodiment will be described. When the IG key 15 is pushed to the ST position 15a by a user's manual operation, the coil 16a of the starter relay 16 is energized and the relay switch 16b is closed, so that the exciting coil 9a incorporated in the electromagnetic switch 9 is energized. The motor contact 10 turns on. At this time, the first switching relay 11 is turned off
In the case of (when the relay switch 11b is turned on to the OFF terminal 11d), only the battery voltage is applied to the starter 5 and the field coil 5a and the armature coil 5b are energized.

On the other hand, when the first switching relay 11 is ON, the first capacitor voltage is added to the battery voltage and applied to the starter 5. However, when the user manually operates the IG key 15 to insert it into the ST position 15a, it is still the first
Since the required charge is not stored in the capacitor 2 of
Normally, the first switching relay 11 is turned off by the ECU 4. When the first switching relay 11 is OFF, the first capacitor 2 is connected to the battery 1 in parallel with the starter 5 to form the first charging circuit, and the resistor 7 and the resistor 8 are connected. The first capacitor 2 is charged according to the voltage division ratio.

When the switch 17 of the electric device 6 is turned on after the IG key 15 is put in the ST position 15a, the second switching relay 14 is off (the relay switch 14b is
Only the battery voltage is applied to the electric device 6 in a state in which the electric power is supplied to the OFF terminal 14d), and the electric device 6 is energized through the diode 18 for preventing backflow from the battery 1.

On the other hand, when the second switching relay 14 is ON, the second capacitor voltage is added to the battery voltage and applied to the electric device 6. However, when the user manually operates the IG key 15 to insert it into the ST position 15a, it is still the second position.
Since the necessary charge is not stored in the capacitor 3 of
Normally, the second switching relay 14 is turned off by the ECU 4. When the second switching relay 14 is OFF, the second capacitor 3 is connected to the battery 1 in parallel with the electric device 6 to form the second charging circuit, and the resistor 12 and the resistor 13 are connected. The second capacitor 3 according to the voltage division ratio of
Is charged.

Next, the control procedure when the engine is temporarily stopped by the eco-run system and then restarted will be described with reference to the flowchart shown in FIG. Step10… Detect the start signal to restart the engine. Step 11 ... Turn on the starter relay 16. Step 12 ... Turns on the first switching relay 11. This allows
The first charging circuit is switched to the first discharging circuit. Step 13 ... Turns on the second switching relay 14. This allows
Switching from the second charging circuit to the second discharging circuit. Step14 ... Turn on the electromagnetic switch 9.

Step 15: Energize the starter 5. Here, the first capacitor voltage is added to the battery voltage and applied to the starter 5. Step16 ... The first switching relay 11 and the second switching relay 1
Detect the energization stop signal for turning OFF 4. Step 17 ... The rotation of the starter 5 is transmitted to the engine and the engine starts. Step18… Turn off the starter relay 16. Step 19 ... Turns off the first switching relay 11. As a result, the first discharging circuit is switched to the first charging circuit. Step 20 ... Turns off the second switching relay 14. As a result, the second discharging circuit is switched to the second charging circuit.

(Effect of First Embodiment) According to the present system described above, the first capacitor voltage and the second capacitor voltage are applied to the starter 5 and the electric device 6 in addition to the battery voltage when the engine is started. The influence of the voltage drop of the battery 1 on the operation of the starter 5 or the operation of the electric device 6 can be prevented.

Further, the first capacitor voltage and the second capacitor voltage only need to compensate for the voltage drop of the battery 1 at the time of starting the engine, so the capacitances of the first capacitor 2 and the second capacitor 3 are required. There is no need to increase the size or connect a plurality of capacitors. As a result, the first capacitor 2 and the second capacitor 3 can be miniaturized (in the present embodiment, only one capacitor is required) and the control is easy, so that the cost can be significantly reduced.

(Second Embodiment) FIG. 3 is a flowchart for determining whether or not to permit automatic stop of the engine based on the capacitor voltage. In this embodiment, when the necessary charge is not stored in the first capacitor 2, the automatic stop of the engine by the eco-run system is prohibited. A specific control method will be described based on the flowchart of FIG.

Step 100 ... It is judged whether or not the engine automatic stop condition is satisfied. For example, the following items are applied as the automatic engine stop condition. The vehicle speed is 0 km / h. The brake pedal is depressed. The gear is in neutral. Here, when all of the above items (1) to (4) are satisfied, it is determined that the engine automatic stop condition is satisfied, and Step 110
Go to. When the engine automatic stop condition is not satisfied,
Proceed to Step 130.

Step 110 ... It is determined whether the first capacitor voltage is equal to or higher than a predetermined value. Here, it is determined whether or not the first capacitor voltage can compensate for the voltage drop of the battery 1 (see FIG. 1) at the time of engine start. If this determination result is YES, Ste
The process proceeds to p120, and if the determination result is NO, the process proceeds to Step130. Step120… Automatically stop the engine. Step130… Prohibit the automatic stop of the engine.

(Effect of Second Embodiment) In the eco-run system described in the first embodiment, the engine is automatically stopped when the vehicle is temporarily stopped at an intersection or a traffic jam, and then the starter is started when the start condition is satisfied. Then, it is a system that restarts the engine. In this case, if the starting time becomes long when the engine is restarted, not only the driver of this vehicle will be annoyed but also other vehicles (drivers) will be annoyed, so it is desirable to restart as soon as possible. .

On the other hand, in the present embodiment, the engine automatic stop is permitted only when the first capacitor voltage is equal to or higher than the predetermined value, and therefore the voltage drop of the battery 1 is calculated when the engine is restarted. The voltage can compensate. As a result, it is possible to prevent the starting time from being lengthened due to the voltage drop of the battery 1 when the engine is restarted, and it is possible to quickly start the engine. Further, when the first capacitor voltage cannot compensate for the voltage drop of the battery 1 when the engine is restarted, the automatic stop of the engine is prohibited, so that the above problem (starting time at restart is Can be avoided).

In this embodiment, it is determined whether or not the engine automatic stop is permitted based on the first capacitor voltage. However, whether or not the engine automatic stop is permitted is determined based on the second capacitor voltage. You may judge whether. in this case,
Since the engine automatic stop is permitted only when the second capacitor voltage is equal to or higher than the predetermined value, it is possible to eliminate the influence of the voltage drop of the battery 1 on the electric device 6 when the engine is restarted.

Further, the automatic stop of the engine is permitted only when both the first capacitor voltage and the second capacitor voltage are both above a predetermined value, and when at least one of the capacitor voltages is below the predetermined value, It may be configured to prohibit the automatic stop of the engine. In this case, the determination value (predetermined value) of the first capacitor voltage and the determination value (predetermined value) of the second capacitor voltage do not necessarily have to be the same value, and each load (starter 5, electric device 6) Different values can be set according to.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an engine starting power supply device.

FIG. 2 is a flowchart showing a control procedure at the time of starting the engine (first embodiment).

FIG. 3 is a flowchart for determining whether or not to permit automatic stop of the engine based on a capacitor voltage (second embodiment).

[Explanation of symbols]

1 Battery 2 1st Capacitor 3 2nd Capacitor 4 ECU (Control Circuit) 5 Starter (Load) 6 Electrical Equipment (Load) 7 Resistance that Limits Charging Current of First Capacitor (First
8) A resistor for dividing the battery voltage (second resistor) 11 A first switching relay 12 A resistor for limiting the charging current of the second capacitor (first resistor) 13 A resistor for dividing the battery voltage (second resistor) Resistance) 14 2nd switching relay 15 IG key

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 F02D 45/00 310G 310S F02N 15/00 F02N 15/00 E H02J 7/00 H02J 7/00 HK (72) Inventor Katsumi Kamiya 1-1, Showa-cho, Kariya city, Aichi F-term inside DENSO (stock) 3G084 BA28 CA01 CA07 DA13 FA03 FA36 3G092 AC03 CA01 EA11 FA30 FA50 GA01 GA10 HF02Z HF19 3G093 BA21 BA22 CA01 DA12 DB19 EC02 FA12 FB05 FB07 5G003 AA04 BA05 CC02 DA07

Claims (3)

[Claims] 1. A charging circuit for storing electric charge in a capacitor by a battery voltage, a discharging circuit for applying a charged voltage of the capacitor to a load in addition to the battery voltage, and a discharging circuit from the charging circuit to the discharging circuit at engine start. An engine starting power supply device comprising circuit switching means for switching, wherein the charging circuit connects a first resistor for limiting a charging current of the capacitor to a battery in series with the capacitor, and the battery voltage. Is connected in parallel with the capacitor with respect to the battery, and the capacitor has a capacity capable of generating a capacitor voltage sufficient to compensate for the voltage drop of the battery at the time of engine start. However, the engine is started according to the voltage division ratio between the first resistance and the second resistance. Movable power supply. 2. The engine starting power supply device according to claim 1, wherein the engine is automatically stopped when a predetermined stop condition is satisfied after the engine is started, and thereafter, the engine is stopped when the predetermined start condition is satisfied. Used in a vehicle equipped with an eco-run system that is automatically started, the circuit switching means includes a switching relay for selectively switching between the charging circuit and the discharging circuit, and a control circuit that controls the operation of the switching relay. The control circuit controls the switching relay to switch from the charging circuit to the discharging circuit when the engine is restarted by the eco-run system. 3. The engine starting power supply device according to claim 2, wherein the control circuit prohibits automatic stop of the engine by the eco-run system until a predetermined amount of charge is stored in the capacitor. Power supply for starting the engine.