JP6790979B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device.

Conventionally, it is provided with an internal combustion engine which is a driving force source for traveling, an alternator capable of generating electric power by the rotation of the internal combustion engine, a starter for starting the internal combustion engine, and a battery which is charged by the alternator and supplies electric power to the starter. Vehicles are known (see, for example, Patent Document 1).

Such a vehicle control device is configured to be capable of executing idling stop control for temporarily stopping the internal combustion engine. In this idling stop control, the internal combustion engine is automatically stopped when the idling stop start condition is satisfied, and the internal combustion engine is automatically restarted when the idling stop end condition is satisfied. This makes it possible to improve fuel efficiency.

JP-A-2015-220863

Here, the vehicle control device permits idling stop control when the SOC (State of Charge) of the battery is equal to or higher than a predetermined value, and prohibits idling stop control when the SOC of the battery is less than a predetermined value. It is configured as follows. Further, the vehicle control device estimates the initial SOC before the ignition is turned on (during the ignition off), and adds the amount of change in the SOC to the initial SOC to calculate the current SOC. It is configured.

However, even if the ignition is turned off and the charging / discharging of the battery is stopped, it may take time to eliminate the influence of polarization, so that the initial SOC cannot be estimated. In this way, if the initial SOC cannot be estimated, the SOC becomes unknown, and it is conceivable that idling stop control is prohibited.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle control device capable of permitting idling stop control even when the charging state is unknown. Is to provide.

The vehicle control device according to the present invention is charged by an internal combustion engine, which is a driving force source for traveling, a generator capable of generating electric power by the rotation of the internal combustion engine, a starter for starting the internal combustion engine, and a starter. It is applied to vehicles equipped with a battery that supplies power to an internal combustion engine. The vehicle control device can execute idling stop control that temporarily stops the internal combustion engine and charge control that adjusts the generated voltage of the generator according to the running state, and generates power when the charge control is prohibited. It is configured so that the generated voltage of the machine is set to a predetermined value, and when the charging state of the battery cannot be estimated when the ignition is off, charging control is prohibited and idling stop control is permitted. ing.

With this configuration, the battery can be charged by the generator, so that idling stop control can be permitted even when the charging state is unknown.

According to the vehicle control device of the present invention, idling stop control can be permitted even when the charging state is unknown.

It is a figure which showed the schematic structure of the vehicle which comprises the ECU by one Embodiment of this invention. It is a block diagram which showed the ECU of FIG. It is a flowchart for demonstrating the control by the ECU of this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, the vehicle 100 including the ECU 5 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the vehicle 100 includes an internal combustion engine 1, an alternator 2, a starter 3, a battery 4, and an ECU 5. The vehicle 100 is configured to travel by a driving force from the internal combustion engine 1.

-Internal combustion engine-
The internal combustion engine 1 is a driving force source for traveling, and is, for example, a multi-cylinder gasoline engine. The internal combustion engine 1 is configured so that the operating state can be controlled by the throttle opening degree (intake air amount), the fuel injection amount, the ignition timing, and the like. An alternator 2 and a starter 3 are mechanically connected to the output shaft of the internal combustion engine 1.

-Alternator-
The alternator 2 is configured to be capable of generating electricity by rotating the internal combustion engine 1. In this alternator 2, it is possible to adjust the amount of generated power by adjusting the generated voltage. The electric power generated by the alternator 2 is used for charging the battery 4 and driving the electric parts of the vehicle 100. The alternator 2 is an example of the "generator" of the present invention.

-Starter-
The starter 3 is provided to start the internal combustion engine 1. The starter 3 is configured to be driven by the electric power supplied from the battery 4. That is, the starter 3 is configured to crank the internal combustion engine 1 by the electric power from the battery 4.

-Battery-
The battery 4 is configured to store the electric power generated by the alternator 2 and supply the stored electric power to the electric parts of the vehicle 100 such as the starter 3. That is, the alternator 2 and the starter 3 are electrically connected to the battery 4. The battery 4 is, for example, a lead storage battery having a rated voltage of 12 V.

-ECU-
The ECU 5 is configured to control the vehicle 100. As shown in FIG. 2, the ECU 5 includes a CPU 51, a ROM 52, a RAM 53, a backup RAM 54, an input interface 55, and an output interface 56. The ECU 5 is an example of the "vehicle control device" of the present invention.

The CPU 51 executes arithmetic processing based on various control programs and maps stored in the ROM 52. The ROM 52 stores various control programs, maps to be referred to when executing the various control programs, and the like. The RAM 53 is a memory that temporarily stores the calculation result by the CPU 51 and the detection result of each sensor. The backup RAM 54 is a non-volatile memory that stores data and the like to be saved when the ignition is turned off.

A crank position sensor 61, an accelerator opening sensor 62, a throttle opening sensor 63, a vehicle speed sensor 64, a brake pedal sensor 65, a voltage sensor 66, a current sensor 67, a temperature sensor 68, an ignition switch 69, and the like are connected to the input interface 55. Has been done.

The crank position sensor 61 is provided to calculate the rotational speed (angular velocity) of the internal combustion engine 1. The accelerator opening sensor 62 is provided to detect the amount of depression of the accelerator pedal (accelerator opening). The throttle opening sensor 63 is provided to detect the throttle opening of the throttle valve. The vehicle speed sensor 64 is provided to calculate the vehicle speed of the vehicle 100. The brake pedal sensor 65 is provided to detect the presence or absence of depression of the brake pedal. The voltage sensor 66 is provided to detect the voltage of the battery 4. The current sensor 67 is provided to detect the charge / discharge current of the battery 4. The temperature sensor 68 is provided to detect the temperature of the battery 4. The ignition switch 69 is provided to switch the ignition on and off.

An injector 11, an igniter 12, a throttle motor 13, an alternator 2, a starter 3, and the like are connected to the output interface 56. The injector 11 is a fuel injection valve, and the fuel injection amount can be adjusted. The igniter 12 is provided to adjust the ignition timing by the spark plug. The throttle motor 13 is provided to adjust the throttle opening degree of the throttle valve.

The ECU 5 is configured to be able to control the operating state of the internal combustion engine 1 by controlling the throttle opening degree, the fuel injection amount, the ignition timing, and the like based on the detection results of each sensor.

Here, the ECU 5 is configured to be able to execute idling stop control for temporarily stopping the internal combustion engine 1. In this idling stop control, the internal combustion engine 1 is automatically stopped when the idling stop start condition is satisfied, and the internal combustion engine 1 is automatically restarted when the idling stop end condition is satisfied. This makes it possible to improve fuel efficiency.

In the ECU 5, for example, when the vehicle speed is equal to or lower than a predetermined value and the brake pedal is depressed, it is determined that the idling stop start condition is satisfied. Further, in the ECU 5, for example, when the depression of the brake pedal is released after the idling stop start condition is satisfied, it is determined that the idling stop end condition is satisfied.

Further, the ECU 5 is configured to be able to execute charge control for adjusting the generated voltage of the alternator 2. In this charge control, the generated voltage is adjusted so that the SOC (State of Charge) of the battery 4 is within a predetermined operating range. Further, in the charge control, the generated voltage of the alternator 2 is adjusted according to the traveling state of the vehicle 100. For example, during constant speed or acceleration, power is mainly supplied from the battery 4 to the electric parts of the vehicle 100, and power generation by the alternator 2 is suppressed to improve fuel efficiency, while deceleration braking is performed by the alternator 2. The battery 4 is charged by the regenerative power generated. That is, the battery 4 is charged by regenerative power generation when the internal combustion engine 1 is driven, while reducing the power generation load when the internal combustion engine 1 is driven to improve fuel efficiency.

Further, the ECU 5 is configured to be able to switch between permission and prohibition of idling stop control and charge control. The ECU 5 is configured to allow idling stop control and charge control when the SOC of the battery 4 is, for example, a predetermined value or more, and prohibit idling stop control and charge control when the SOC of the battery 4 is less than a predetermined value. Has been done. When charging control is prohibited, the generated voltage of the alternator 2 is set to a predetermined value. This predetermined value is, for example, a constant value preset so that the battery 4 is in a fully charged state. Therefore, when the SOC of the battery 4 is less than a predetermined value, idling stop control and charge control for improving fuel efficiency are prohibited, and charging of the battery 4 is prioritized. That is, this predetermined value is, for example, a preset value, and is a threshold value for determining whether or not it is necessary to prioritize charging of the battery 4 over improving fuel efficiency.

Further, the ECU 5 is configured to calculate the SOC of the battery 4. Specifically, the initial SOC is estimated before the ignition is turned on (during the ignition off), and the amount of change in the SOC is added to the initial SOC to calculate the current SOC. The initial SOC regards the voltage of the battery 4 at the time of ignition off (the battery voltage in a state where the influence of polarization is eliminated) as the OCV (Open Circuit Voltage) of the battery 4, and the OCV and SOC of the battery 4 It is calculated based on the OCV-SOC map showing the relationship with. That is, the OCV-SOC map is stored in the ROM 52 of the ECU 5, and the initial SOC is derived from the voltage of the battery 4 (detection result of the voltage sensor 66) at the time of ignition off using the OCV-SOC map. The amount of change in SOC is calculated based on the integrated value of the charge / discharge current of the battery 4.

Here, even if the ignition is turned off and the charging / discharging of the battery 4 is stopped, it takes time to eliminate the influence of polarization, so that the initial SOC may not be estimated in some cases. For example, if a predetermined time elapses while the voltage of the battery 4 is stable after the ignition is turned off, it can be determined that the influence of polarization has been eliminated. Therefore, the voltage of the battery 4 at that time is used for the initial SOC. However, if the ignition is turned on before the predetermined time elapses while the voltage of the battery 4 is stable, the initial SOC cannot be estimated. Therefore, in the present embodiment, the ECU 5 is configured to prohibit charge control and allow idling stop control when the initial SOC cannot be estimated.

-Control by ECU-
Next, the control by the ECU 5 of the present embodiment will be described with reference to FIG. The following flow is repeated at predetermined time intervals. Further, each of the following steps is executed by the ECU 5.

First, in step S1 of FIG. 3, it is determined whether or not the ignition is turned on. For example, when the ignition switch 69 is turned on, it is determined that the ignition is turned on. Then, when it is determined that the ignition is turned on, the process proceeds to step S2. On the other hand, when it is determined that the ignition is not turned on (when the ignition off is continued), the process proceeds to step S6.

Next, in step S2, it is determined whether or not the initial SOC can be estimated during the ignition off (in step S6 described later). Then, when it is determined that the initial SOC has been estimated, the process proceeds to step S3. On the other hand, if it is determined that the initial SOC cannot be estimated, the SOC becomes unknown, so the process proceeds to step S7.

Next, in step S3, the current SOC is estimated by adding the amount of change in SOC to the initial SOC. The amount of change in SOC is calculated based on the integrated value of the charge / discharge current of the battery 4 detected by the current sensor 67.

Next, in step S4, permission and prohibition of idling stop control and charge control are determined based on the current SOC. For example, if the current SOC is greater than or equal to a predetermined value, idling stop control and charge control are permitted, and if the current SOC is less than a predetermined value, idling stop control and charge control are prohibited.

When the idling stop control is permitted, the internal combustion engine 1 is automatically stopped when the idling stop start condition is satisfied, and the internal combustion engine 1 is automatically restarted when the idling stop end condition is satisfied. Further, when the charge control is permitted, the generated voltage of the alternator 2 is adjusted according to the current SOC, the running state of the vehicle 100, and the like.

When the idling stop control and the charge control are prohibited, the internal combustion engine 1 is not automatically stopped and the generated voltage of the alternator 2 is set to a predetermined value. This predetermined value is, for example, a constant value preset so that the battery 4 is in a fully charged state. Therefore, the electric power generated by the alternator 2 charges the battery 4 and drives the electric parts of the vehicle 100.

Next, in step S5, it is determined whether or not the ignition is turned off. For example, when the ignition switch 69 is turned off, it is determined that the ignition is turned off. Then, when it is determined that the ignition is not turned off (when the ignition is continued on), the process returns to step S3. On the other hand, if it is determined that the ignition is turned off, the process proceeds to step S6.

Next, in step S6, the initial SOC is estimated. For example, when a predetermined time elapses in a state where the voltage of the battery 4 is stable after the ignition is turned off, the initial SOC is estimated based on the voltage of the battery 4 at that time, and the return is started. On the other hand, if the voltage of the battery 4 is stable and the predetermined time has not elapsed after the ignition is turned off, it is determined that the initial SOC cannot be estimated, and the process proceeds to return. The stable voltage of the battery 4 is a state in which the voltage of the battery 4 is within a predetermined range. Further, the predetermined time is, for example, a preset time for determining whether or not the influence of polarization is eliminated.

If the initial SOC cannot be estimated (step S2: No), charge control is prohibited in step S7. Therefore, the generated voltage of the alternator 2 is set to a predetermined value. Therefore, the electric power generated by the alternator 2 charges the battery 4 and drives the electric parts of the vehicle 100. That is, if the internal combustion engine 1 is in operation, the battery 4 is not discharged.

Next, in step S8, it is determined whether or not the voltage of the battery 4 is equal to or higher than a predetermined value. This predetermined value is, for example, a preset value and is a threshold value for determining whether or not idling stop control can be permitted. When it is determined that the voltage of the battery 4 is equal to or higher than a predetermined value, the battery capacity for driving the starter 3 is secured in the battery 4 when the internal combustion engine 1 is restarted, so that step S9 Move on to. On the other hand, when it is determined that the voltage of the battery 4 is not equal to or higher than the predetermined value (when the voltage of the battery 4 is less than the predetermined value), the battery for driving the starter 3 when the internal combustion engine 1 is restarted. Since the capacity is not secured in the battery 4, the process proceeds to step S10.

Then, in step S9, idling stop control is permitted. Therefore, the internal combustion engine 1 is automatically stopped when the idling stop start condition is satisfied, and the internal combustion engine 1 is automatically restarted when the idling stop end condition is satisfied. When the internal combustion engine 1 is stopped, the alternator 2 does not generate electricity, and when the internal combustion engine 1 is restarted, electric power is supplied from the battery 4 to drive the starter 3. Then, the process proceeds to step S11.

Further, in step S10, idling stop control is prohibited. Therefore, the internal combustion engine 1 is not automatically stopped. Then, the process proceeds to step S11.

Next, in step S11, it is determined whether or not the ignition is turned off. Then, when it is determined that the ignition is not turned off (when the ignition is continued on), the process returns to step S7. On the other hand, if it is determined that the ignition is turned off, the process proceeds to step S6.

-Effect-
In the present embodiment, as described above, when the initial SOC cannot be estimated at the time of ignition off, the battery 4 can be charged by the alternator 2 by prohibiting the charging control and permitting the idling stop control. Therefore, even when the SOC is unknown, idling stop control can be permitted. As a result, deterioration of fuel efficiency can be suppressed.

Further, in the present embodiment, when the initial SOC cannot be estimated at the time of ignition off, idling stop control is permitted when the voltage of the battery 4 is equal to or higher than a predetermined value, and the voltage of the battery 4 is lower than the predetermined value. In this case, by prohibiting the idling stop control, the idling stop control can be permitted after the battery capacity for driving the starter 3 is secured in the battery 4 when the internal combustion engine 1 is restarted.

-Other embodiments-
It should be noted that the embodiment disclosed this time is an example in all respects and does not serve as a basis for a limited interpretation. Therefore, the technical scope of the present invention is not construed solely by the above-described embodiments, but is defined based on the description of the claims. In addition, the technical scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

For example, in the present embodiment, the internal combustion engine 1 is a multi-cylinder gasoline engine, but the present invention is not limited to this, and the internal combustion engine may be a diesel engine or the like.

Further, in the present embodiment, an example in which an alternator 2 functioning as a generator is provided is shown, but the present invention is not limited to this, and a motor generator functioning as a generator and an electric motor may be provided instead of the alternator.

Further, in the present embodiment, the example in which the battery 4 is a lead storage battery is shown, but the present invention is not limited to this, and the battery may be a nickel hydrogen secondary battery or the like. Further, the lead storage battery and the nickel hydrogen secondary battery may be connected in parallel.

Further, in the present embodiment, the ECU 5 may be composed of a plurality of ECUs.

According to the present invention, an internal combustion engine, which is a driving force source for traveling, a generator capable of generating electric power by the rotation of the internal combustion engine, a starter for starting the internal combustion engine, charging by the generator, and supplying electric power to the starter. It can be used as a vehicle control device for controlling a vehicle equipped with a battery.

1 Internal combustion engine 2 Alternator (generator)
3 Starter 4 Battery 5 ECU (Vehicle control device)
100 vehicles

Claims (1)

An internal combustion engine that is a driving force source for traveling, a generator that can generate electric power by the rotation of the internal combustion engine, a starter that starts the internal combustion engine, and a starter that is charged by the generator and supplies electric power to the starter. A vehicle control device applied to a vehicle equipped with a battery.
It is possible to execute idling stop control for temporarily stopping the internal combustion engine and charge control for adjusting the generated voltage of the generator according to a running state , and when the charge control is prohibited, the generator of the generator It is configured so that the generated voltage is set to a predetermined value .
A vehicle control device characterized in that when the charge state of the battery cannot be estimated at the time of ignition off, the charge control is prohibited and the idling stop control is permitted.

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