JP2002038984A - Idle stop vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an idle stop vehicle capable of preventing various failures of electric load caused by a drop in voltage, by restraining the drop in voltage of a battery in cranking. SOLUTION: This idle stop vehicle stops an engine when the engine stopping condition is established, and starts the engine by operating a starter means when the engine starting condition is established. When the engine starting condition is established and when the battery voltage is lowered to a first set value or less with the operation of the starter means 4, a voltage compensation means 6 is operated by a control means 7 to compensated the battery voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle stop vehicle for automatically stopping an engine temporarily when a vehicle stops at a traffic light or the like.

[0002]

2. Related Background Art In recent years, an idle stop vehicle has been put to practical use in which an engine is temporarily stopped automatically for the purpose of saving fuel consumption and reducing emissions when the vehicle is stopped at a traffic light or the like. Have been. In this type of vehicle, an engine stop condition such as a vehicle speed of 0 km / h, idle operation, clutch connection, etc. is satisfied, and the engine is automatically stopped when it is assumed that the vehicle is stopped, and then operation such as clutch disconnection is performed. When an engine start condition indicating a driver's intention to start is satisfied, the engine is automatically started by the starter to prepare for start.

[0003]

As is well known, a starter for cranking an engine requires a considerable amount of power consumption. Therefore, especially in an urban area where frequent stops and starts are repeated, the start frequency of the engine is reduced. With the increase, the consumption of the battery as the power source becomes severe. Also, for example, even if the compressor of the air conditioner is not driven due to the stop of the engine, it is possible to supply cool air for a while by using a low-temperature evaporator. The operation of the air conditioner fan has been continued,
Such control is also a factor promoting the consumption of the battery.

As a result, a phenomenon occurs in which the battery voltage temporarily drops at the moment of cranking. As a result, for example, the ECU (electronic control unit) for controlling the engine is reset, and the learning contents and the like up to that point are reset. Or the lighting of the instruments is temporarily darkened, and the quality of the vehicle is greatly impaired.

It is an object of the present invention to provide an idle stop vehicle capable of suppressing a voltage drop of a battery at the time of cranking and preventing various problems of an electric load caused by the voltage drop. is there.

[0006]

In order to achieve the above object, the invention according to claim 1 stops the engine when a preset engine stop condition is satisfied, and sets a starter means when the preset engine start condition is satisfied. In an idle stop vehicle that starts the engine by operating the engine, a voltage compensating unit that is provided between the battery and the electric load of the vehicle to compensate the battery voltage, and that the engine start condition is satisfied and the starter unit operates. Control means for activating the voltage compensating means when the battery voltage falls below the first set value.

For example, in an urban area where the vehicle is repeatedly stopped and started, the frequency of starting the engine is significantly increased. Therefore, the power consumption due to the operation of the starter is larger in the idle stop vehicle than in the normal vehicle. As a result, the battery is easily consumed. When the battery voltage decreases below the first set value due to the operation of the starter means due to the consumption of the battery, the control means activates the voltage compensating means to compensate the battery voltage. Therefore, the electric load continues to operate normally and various troubles caused by the voltage drop, for example, the ECU
This prevents problems such as the disappearance of the learning contents or the like due to the resetting of the vehicle or the deterioration of the quality of the vehicle due to the temporary darkening of the lighting of the instruments.

According to a second aspect of the present invention, the control means stops the operation of the voltage compensating means when the battery voltage becomes equal to or higher than the second set value due to the operation of the alternator upon completion of the start of the engine. It is configured as follows. Therefore, when the battery voltage becomes equal to or higher than the second set value due to the alternator power generation, the operation of the voltage compensating means is stopped, assuming that the battery voltage need not be compensated.

According to a third aspect of the present invention, the control means inhibits the operation of the voltage compensating means when a predetermined time has elapsed since the engine was stopped, or when the start is not completed even when the starter means is operated. It is composed. Therefore,
In a situation where the battery has been significantly depleted, e.g., when a predetermined time has elapsed since the engine stopped or when the engine failed to start, the operation of the voltage compensating means is prohibited and the engine start is prioritized, and the current from the battery is used to start the engine. When used effectively, the probability of successful startup is increased.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an idle stop vehicle with a manual transmission will be described below. FIG. 1 is a block diagram showing an electric configuration of an idle stop vehicle according to the present embodiment. A battery 1 mounted on the vehicle includes various electric loads 2 of the vehicle, for example, an ignition system (ignition coil or the like) of an engine (not shown). ), A fuel injection system (such as an injector), an ECU that controls the engine, lights of the vehicle, an air conditioner, and the like. Further, an alternator 3 is connected to the battery 1, and the alternator 3 supplies a current generated by driving the engine to the electric load 2 and charges the battery 1 with surplus current. A starter 4 as starter means is connected to the battery 1, and the starter 4 is operated by a current from the battery 1 in response to a start operation of an ignition key by a driver to crank an engine.

An E / G stop / start controller 5 is connected to the starter 4.
Is an idle stop process that is capable of interrupting the operation of the engine ignition system and fuel injection system and of activating the starter 4, and that automatically stops the engine temporarily when the vehicle stops, as described later. Is to be executed.

A voltage compensation circuit 6 as voltage compensation means is interposed between the battery 1 and the electric load 2, and a voltage compensation controller 7 as control means is connected to the voltage compensation circuit 6. The voltage compensation controller 7 includes:
The engine stop signal from the E / G stop / start controller 5, the operation signal from the alternator 3, and the battery 1
The input voltage (that is, the battery voltage) to the voltage compensating circuit 6 is input from the power supply.

FIG. 2 is an electric circuit diagram showing a simple example of the voltage compensating circuit 6. The battery 1 is connected to an electric load 2 via a diode 11, and a discharge circuit is provided between the diode 11 and the electric load 2. It is grounded via a switch 12, a diode 13, and a capacitor 14. Diode 13
A resistor 15 and a diode 1
6, connected between the battery 1 and the diode 11 via the charging switch 17;
And the charging switch 17 is switched by the voltage compensation controller 6.

When the discharging switch 12 is opened and the charging switch 17 is closed, the current from the battery 1 is supplied to the capacitor 14 via the charging switch 17, the diode 16, and the resistor 15, and the capacitor 14 is charged. You. When the discharging switch 12 is closed and the charging switch 17 is opened, the current discharged from the capacitor 14 is supplied to the electric load 2 via the diode 13 and the discharging switch 12.

Next, the idle stop process of the idle stop vehicle configured as described above and the accompanying voltage compensation process will be described. As described above, the idle stop process is executed by the E / G stop / start controller 5. The E / G stop / start controller 5 constantly determines whether or not a preset engine stop condition is satisfied during operation of the engine. In the present embodiment, it is considered that the engine stop condition is satisfied when all of the following three requirements are satisfied.

1) The vehicle speed is 0 km / h. 2) The engine is running idle. 3) The clutch is engaged. The E / G stop / start controller 5 is detected by a vehicle speed sensor (not shown). The above requirements are determined based on the vehicle speed, the engine speed detected by the engine speed sensor, and the clutch connection / disconnection state detected by the clutch stroke sensor. When all the requirements are satisfied and the engine stop condition is satisfied, it is considered that the vehicle is stopped and the engine can be stopped, and the operation of the ignition system and the fuel injection system of the engine is stopped to stop the engine, and the engine stop signal is output. Is output to the voltage compensation controller 6.

While the engine is stopped, the E / G stop / start controller 5 determines whether or not a preset engine start condition is satisfied. In the present embodiment, it is determined that the engine start condition is satisfied when only the condition 3) is not satisfied from the state where the engine stop condition is satisfied as described above. Therefore, when the driver determines that the clutch is to be disengaged and the driver intends to start the vehicle, the E / G stop / start controller 5 restarts the operation of the ignition system and the fuel injection system of the engine and starts the starter. 4
Activate As a result, the engine is cranked and started to prepare for the subsequent start.

The idling stop process is performed as described above. For example, in an urban area where stop and start are frequently repeated, the engine start frequency (in other words, the starter 4) is used.
Operation frequency) will be significantly increased. Therefore, compared to a normal vehicle, the idle stop vehicle consumes much more power due to the operation of the starter 4,
The battery 1 is much more likely to be consumed. At the time of starting, the alternator 3 does not generate electric power, and the starter 4 is operated only with the current supplied from the battery 1. Therefore, a phenomenon occurs in which the battery voltage temporarily drops at the moment of cranking. In order to cope with such a voltage drop, the voltage compensation controller 7 performs a voltage compensation process.

During normal engine operation, the voltage compensation controller 7 operates the discharge switch 1 of the voltage compensation circuit 6.
2 and the charging switch 17 are both open to prevent charging and discharging of the capacitor 14. Then, as described above, the E / G stop / start controller 5
When the engine stop signal is input from the controller, the voltage compensation controller 7 closes the charging switch 17. Therefore, the current from the battery 1 is applied to the charging switch 1 of the voltage compensation circuit 6.
7, supplied to the capacitor 14 via the diode 16 and the resistor 15, and the charging of the capacitor 14 is started.

Thereafter, the voltage compensation controller 7 monitors the input voltage from the battery 1 to the voltage compensation circuit 6. As described above, the starter 4 is operated in accordance with the establishment of the engine start condition. However, when the consumption of the battery 1 is small (the battery charge amount is large), the input voltage does not decrease so much even at the moment of cranking. When the battery 1 is held at or above the first set value set in advance and the consumption of the battery 1 is large (the battery charge amount is small), the input voltage is greatly reduced and falls below the first set value.

As the first set value, a value is set that allows for a margin for the minimum operating voltage at which the electric load 2 can operate normally. As the minimum operating voltage, for example, about 6 volts or more is required for the ECU, and about 10 volts or more is required for lights and air conditioners. In this case, a value obtained by adding a margin to 10 volts is used. It is set as a first set value. When the input voltage is maintained at the first set value or more during the operation of the starter 4, the voltage compensation controller 7 does not perform any processing, but even in this case, the electric load 2 continues to operate normally. Become.

On the other hand, when the input voltage falls below the first set value during starter operation due to the consumption of the battery 1, the voltage compensation controller 7 opens the charging switch 17 and closes the discharging switch 12 at the same time. The capacitor 14 starts discharging, and its current is supplied to the electric load 2 via the diode 13 and the discharging switch 12. as a result,
The voltage applied to the electric load 2 is boosted as compared with the case where only the battery 1 is used. The applied voltage after boosting at this time is
In order to operate the electric load 2 normally, it is necessary that the voltage is equal to or higher than the minimum operating voltage. However, even if the voltage exceeds the adjustment voltage of the alternator 3, unnecessary power consumption is merely caused.

Therefore, the specification of the capacitor, for example, the capacitance, is set so that the voltage applied to the electric load 2 at the time of discharging the capacitor is within the above range (the range from the minimum operating voltage to the adjustment voltage). ing. Then, the electric load 2 continues to operate normally due to the increase of the applied voltage, and various troubles of the electric load caused by the voltage drop, for example, disappearance of learning contents or the like due to reset of the ECU, or lighting of instruments and the like. It is possible to prevent such a problem that the vehicle is temporarily darkened and the quality of the vehicle is impaired.

When the start of the engine is completed by cranking and the power generation by the alternator 3 is started, an operation signal from the alternator 3 is input to the voltage compensation controller 7. When the input voltage from the battery 1 to the voltage compensation circuit 6 becomes equal to or more than the second set value after the input of the operation signal, the voltage compensation controller 7 opens the discharge switch 12 and returns to the initial state. As the second set value,
For example, a value slightly lower than the adjustment voltage of the alternator 3 is set. That is, the discharge of the capacitor 14 is interrupted at an appropriate timing when the input voltage becomes equal to or higher than the second set value and the boosting is not required. Therefore, there is an advantage that the power required for the next charging is reduced by the power remaining in the capacitor 14 and unnecessary power consumption can be suppressed.

On the other hand, after the automatic stop of the engine, the voltage compensation controller 7 constantly monitors the operation signal from the alternator 3, and when the operation signal is not input for a predetermined time, the charging of the capacitor 14 is interrupted at that time, and After that, even if the engine start condition is satisfied and the input voltage falls below the first set value due to the operation of the starter 4, the above-described boosting by the voltage compensation circuit 6 is not performed. Similarly, when the start by the starter 4 is not completed even if the start is tried a predetermined number of times (when the start of the engine fails), similarly, the boosting by the voltage compensation circuit 6 is not performed.

That is, when the charged state of the capacitor is maintained for a long time, or when starting is attempted many times, it is presumed that the battery 1 is extremely consumed. The priority is given to completion, and the power consumption for charging the capacitor is suppressed. By this processing, the current from the battery 1 is effectively used for the starter operation, the ignition system, and the fuel injection system. Therefore, the probability of successful start is increased, and a situation in which starting is impossible can be avoided. .

Although the description of the embodiments has been completed above, embodiments of the present invention are not limited to these embodiments. For example,
In the above embodiment, the present invention is embodied in an idle stop vehicle with a manual transmission. However, the type of the transmission is not limited to this, and may be embodied in an idle stop vehicle with an automatic transmission. Further, in the above embodiment, the voltage compensating circuit 6 is configured to boost the input voltage from the battery 1 using the discharge from the capacitor 14, but the configuration of the voltage compensating circuit 6 is not limited to this. For example, the voltage compensating circuit 6 is constituted by a well-known DC-DC converter, and when the starter 4 operates and the input voltage from the battery 1 falls below the first set value, the input voltage is reduced by the DC-DC converter. , The minimum operating voltage may be secured.

Further, in the above-described embodiment, when the input voltage from the battery 1 becomes equal to or higher than the second set value due to the power generation of the alternator 3, the discharging switch 12 is opened to interrupt the discharging of the capacitor 14. It is not always necessary to interrupt the discharge. For example, the capacitor may be completely discharged while the discharge switch 14 is kept closed. On the other hand, in the above-described embodiment, the boosting by the voltage compensating circuit 6 is prohibited when a predetermined time has elapsed since the engine was stopped or the engine failed to start, but the voltage compensating circuit 6 is also operated in this case. You may make it pressurize.

[0029]

As described above, according to the idling stop vehicle of the first aspect, the voltage drop of the battery at the time of cranking is suppressed, and various problems of the electric load caused by the voltage drop are prevented. Can be prevented. According to the idle stop vehicle of the second aspect, in addition to the first aspect, the operation of the voltage compensating means can be stopped at an appropriate timing to suppress unnecessary power consumption.

Further, according to the idle stop vehicle of the third aspect of the present invention, in addition to the first aspect of the present invention, when the battery is extremely consumed, the operation of the voltage compensating means is inhibited and the current from the battery is supplied to the engine. Since it is used effectively for starting, a situation where starting is impossible can be avoided beforehand.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of an idle stop vehicle according to an embodiment.

FIG. 2 is an electric circuit diagram showing a simple example of a voltage compensation circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Electric load 4 Starter (starter means) 6 Voltage compensation circuit (voltage compensation means) 7 Voltage compensation controller (control means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/06 F02D 29/06 L F02N 11/08 F02N 11/08 XY 15/00 15/00 EF Term (reference) 3G092 AA01 AB02 AC03 BA08 BB10 CA01 CB04 CB05 EA14 EA15 EA21 EB08 EC03 FA30 FA32 FA40 FA43 FB05 GA01 GA10 GB01 HB01X HC08X HE01Z HF01X HF01Z HF15Z HF19Z HF20Z DA03BA01 DA03 BA09 DA03 BA09 EA05 EA12 EB09 EC01 FA01 FA06 FA11 FA12

Claims (3)

[Claims] 1. An idle-stop vehicle that stops an engine when a preset engine stop condition is satisfied and activates starter means when a preset engine start condition is satisfied to start the engine. A voltage compensating means provided between the electric load and the battery, for compensating a battery voltage; and when the engine start condition is satisfied and the battery voltage decreases to a first set value or less with the operation of the starter means. An idle stop vehicle comprising: a control unit for operating the voltage compensation unit. 2. The method according to claim 1, wherein the control means stops the operation of the voltage compensating means when the battery voltage becomes equal to or higher than a second set value in accordance with the operation of the alternator upon completion of the start of the engine. The idle stop vehicle according to claim 1. 3. The system according to claim 2, wherein the control means inhibits the operation of the voltage compensating means when a predetermined time has elapsed since the engine was stopped, or when the start is not completed even when the starter means is operated. 2. The idle stop vehicle according to 1.