Control device for hybrid vehicle

Abstract

To provide a control device for a hybrid vehicle, capable of suppressing overdischarge of a battery.SOLUTION: A hybrid vehicle includes: an engine as a travel power source; a fuel tank storing fuel supplied to the engine; a battery; and a motor which, when there is a request to charge the battery, can generate electric power for charging the battery therewith, using power of the engine, and which is supplied with electric power from the battery and can be driven as a travel power source. A control device for the hybrid vehicle includes: a first determination section for determining whether a fuel dilution ratio is a threshold or greater, the fuel dilution ratio being a ratio of an amount of fuel newly supplied to the fuel tank to an amount of fuel in the fuel tank before fuel supply; a second determination section for determining whether there is a request to charge the battery; a third determination section for determining whether an SOC of the battery is a determination value or less; and a notification control section for notifying a driver of a warning of urging the driver to stop the vehicle when affirmative determinations are made by the first, second, and third determination sections.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle.

Background Art

[0002] A hybrid vehicle equipped with an engine and a motor as driving power sources is known. The motor can generate electricity using the output of the engine, and the electricity generated by the motor is charged into the battery (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a hybrid vehicle, an incompatible fuel may be accidentally refueled. For example, when light oil is refueled into a hybrid vehicle equipped with a gasoline engine, or when gasoline is refueled into a hybrid vehicle equipped with a diesel engine. In such cases, the output of the engine decreases, and there is a risk that the battery will be over-discharged without being charged.

[0005] Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that suppresses over-discharge of the battery.

Means for Solving the Problems

[0006] The above object is achieved by a control device for a hybrid vehicle having an engine as a driving power source, a fuel tank storing fuel supplied to the engine, a battery, and a motor capable of generating electric power for charging the battery using the power of the engine when there is a charging request for the battery and capable of being driven as a driving power source by receiving power from the battery. The control device includes a first determination unit that determines whether a fuel dilution rate, which is a ratio of the amount of fuel newly supplied to the fuel tank to the amount of fuel in the fuel tank before refueling, is equal to or greater than a threshold value, a second determination unit that determines whether there is a charging request for the battery, a third determination unit that determines whether the state of charge (SOC) of the battery is equal to or less than a determination value, and a notification control unit that executes a notification process for notifying a driver to stop when an affirmative determination is made by the first, second, and third determination units.

Effect of the Invention

[0007] It is possible to provide a control device for a hybrid vehicle that suppresses over-discharge of the battery.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] [Schematic Configuration of Hybrid Vehicle] Figure 1 is a schematic configuration diagram of the hybrid vehicle 1. In the hybrid vehicle 1, a clutch 30, a motor 40, and a transmission 50 are sequentially provided in the power transmission path from the engine 10 to the drive wheels 70. The engine 10 and the motor 40 are mounted as driving sources for the running of the hybrid vehicle 1. The engine 10 is, for example, a gasoline engine, but it may also be a diesel engine. The engine 10 is supplied with fuel stored in the fuel tank 12. The transmission 50 and the left and right drive wheels 70 are connected via a differential gear 60. The transmission 50 includes a torque converter and an automatic transmission.

[0010] The clutch 30 is provided between the engine 10 and the motor 40 on the same power transmission path. Note that the clutch 30 may not be provided, and the power of the engine 10 may be constantly transmitted to the motor 40.

[0011] The motor 40 is connected to the battery 90 via the PCU 80. The motor 40 functions as a driving power source for the running of the hybrid vehicle 1 in response to the power supply from the battery 90. Further, the motor 40 also functions as a generator that charges the battery 90 in response to the power transmission from the engine 10 or the drive wheels 70. The motor 40 can start the engine 10 by cranking the engine 10 when the clutch 30 is engaged.

[0012] The PCU 80 is controlled by the ECU 100 described later. In the case of a power running operation in which the motor 40 outputs torque, the PCU 80 converts the DC voltage of the battery 90 into an AC voltage and adjusts the power supplied to the motor 40. In the case of a regenerative operation in which the motor 40 generates electricity, the PCU 80 converts the AC voltage from the motor 40 into a DC voltage and adjusts the regenerative power supplied to the battery 90.

[0013] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the vehicle. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory in which control programs and data are stored. The ECU 100 is an example of a control device for the hybrid vehicle 1. Specifically, the ECU 100 functionally realizes a first determination unit, a second determination unit, a third determination unit, and a notification control unit, which will be described later in detail.

[0014] An ignition switch 3, a crank angle sensor 11, and a fuel gauge 14 are electrically connected to the ECU 100. The ignition switch 3 outputs a signal corresponding to the on / off state of the ignition to the ECU 100. The crank angle sensor 11 detects the rotational speed of the engine 10. The fuel gauge 14 detects the amount of fuel in the fuel tank 12. A display unit 110 is electrically connected to the ECU 100. The display unit 110 is controlled by the ECU 100 and is provided on the instrument panel of the vehicle.

[0015] The ECU 100 runs the hybrid vehicle 1 either in motor running or hybrid running. In motor running, the ECU 100 stops the engine 10 and releases the clutch 30, and runs by the power of the motor 40. In hybrid running, the clutch 30 is engaged and the vehicle runs at least by the power of the engine 10. Also, in hybrid running, the output of the motor 40 can assist the driving of the engine 10.

[0016] The switching between motor running and hybrid running is performed based on the required torque for the hybrid vehicle 1 obtained from the vehicle speed and the accelerator opening. For example, when the required torque is less than the starting threshold for starting the engine 10, motor running with the engine 10 stopped is selected to improve fuel efficiency. When the required torque is greater than or equal to the starting threshold for starting the engine 10, hybrid running with the engine 10 started is selected.

[0017] [Battery Protection Control] The ECU 100 executes battery protection control to prevent the battery 90 from being over-discharged when misfueling occurs. FIG. 2 is a flowchart illustrating the battery protection control. FIG. 3 is a timing chart illustrating the battery protection control. FIG. 3 shows the transition of the fuel dilution rate, circulation flag, charge request flag, charge limit flag, and SOC.

[0018] First, the ECU 100 determines whether the fuel dilution rate is equal to or greater than a threshold value (step S1). The fuel dilution rate is the ratio of the amount of fuel newly supplied to the fuel tank 12 to the amount of fuel in the fuel tank 12 before fuel supply. For example, when the fuel amount F2 immediately after ignition on is greater than the fuel amount F1 immediately before ignition off, it can be regarded as fuel supply. The fuel dilution rate in this case is calculated by (F2 - F1) / F1. Note that the amount of fuel in the fuel tank 12 is calculated based on the detection value of the fuel gauge 14. The threshold value is, for example, 50%, but is not limited to this. The threshold value is set to the minimum value of the fuel dilution rate at which there is a risk that the output of the engine 10 will decrease and the battery 90 will be over-discharged when misfueling occurs. If the result in step S1 is No, this control ends. Step S1 is an example of the process executed by the first determination unit.

[0019] If the result in step S1 is Yes, the ECU 100 turns on the dilution determination flag (time t1), and further determines whether the engine 10 is running (step S2). If the result in step 2 is No, this control ends.

[0020] If the answer in step S2 is Yes, the ECU 100 determines whether the fuel in the fuel tank 12 has sufficiently circulated in the engine 10 (step S3). Specifically, when the integrated rotation speed since the engine 10 started is equal to or greater than a predetermined value, it is determined that the fuel in the fuel tank 12 has sufficiently circulated in the engine 10. The integrated rotation speed is calculated based on the integrated value of the detection values of the crank angle sensor 11. The predetermined value is set to the integrated value of the rotation speed of the engine 10 required until the fuel in the fuel tank 12 sufficiently circulates in the engine 10 after the engine 10 starts. If the answer in step S3 is No, this control ends.

[0021] If the answer in step S3 is Yes, the ECU 100 turns on the circulation determination flag (time t2). Further, the ECU 100 determines whether there is a charging request to the battery 90 (step S4). Specifically, when the charging request flag is on, it is determined that there is a charging request. If the answer in step S4 is No, this control ends. Step S4 is an example of the process executed by the second determination unit.

[0022] If the answer in step S4 is Yes (time t3), the ECU 100 determines whether the SOC of the battery 90 is decreasing (step S5). Specifically, the SOC is acquired at predetermined time intervals, and when the current value of the SOC is lower than the previous value, it is determined that the SOC is decreasing. If the answer in step S5 is No, this control ends. Note that the SOC is calculated by the ECU 100 based on the voltage value and current value of the battery 90.

[0023] If the answer in step S5 is Yes (time t3), it indicates that although there is a charging request to the battery 90, the output of the engine 10 has decreased and sufficient power has not been charged to the battery 90. In this case, the ECU 100 determines whether there is a charging limit request to limit the charge amount of the battery 90 (step S6). Specifically, when the charging limit flag is on, it is determined that there is a charging limit request. If the answer in step S6 is Yes, this control ends.

[0024] If the answer is No in step S6 (time t3), it is regarded that misfueling has occurred. In this case, the ECU 100 determines whether the SOC of the battery 90 is equal to or lower than the notification determination value (step S7). If the answer is No in step S7, this control ends.

[0025] If the answer is Yes in step S7 (time t4), the ECU 100 executes a notification process for notifying the driver to stop the vehicle (step S8). Specifically, the ECU 100 causes the display unit 110 to display a warning prompting the driver to stop the vehicle. By stopping the hybrid vehicle 1 according to the warning, over-discharge of the battery 90 is suppressed. Note that the method of notification is not limited to this. For example, the above warning may be notified by sound through a speaker of the vehicle's audio system, navigation system, or the like. Step S7 is an example of the process executed by the third determination unit. Step S8 is an example of the process executed by the notification control unit.

[0026] Next, the ECU 100 determines whether the SOC of the battery 90 is equal to or lower than the system stop determination value (step S9). The system stop determination value is a value lower than the above-described notification determination value. If the answer is No in step S9, this control ends.

[0027] If the answer is Yes in step S9 (time t5), for example, if the driver ignores the above warning and continues to drive, the ECU 100 executes a system stop process for stopping the system (step S10). Specifically, the ECU 100 stops driving the engine 10 and the motor 40 to make the vehicle in a non-drivable state, and causes the display unit 21 to display that the system is stopped in order to protect the battery 90. Thereby, over-discharge of the battery 90 can be prevented.

[0028] In the above embodiment, as an example of a hybrid vehicle, one equipped with an engine 10 and a motor 40 as a driving power source was exemplified, but the present invention is not limited thereto. For example, a hybrid vehicle may be provided with an engine, a first motor, and a second motor as a driving power source, and further includes a planetary gear mechanism including a sun gear connected to the first motor, a drive wheel, a ring gear connected to the second motor, and a carrier connected to the engine.

[0029] As described above in detail with respect to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0030] 1 Hybrid vehicle 10 Engine 40 Motor 90 Battery 100 ECU (Control device, first determination unit, second determination unit, third determination unit, notification control unit)

Claims

【Claim 1】 A control device for a hybrid vehicle having an engine as a driving power source, a fuel tank storing fuel supplied to the engine, a battery, and a motor capable of generating electric power for charging the battery by using the power of the engine when there is a charging request to the battery and capable of being driven as a driving power source by receiving power from the battery, comprising: A first determination unit that determines whether a fuel dilution rate, which is a ratio of the amount of fuel newly supplied to the fuel tank to the amount of fuel in the fuel tank before refueling, is equal to or greater than a threshold value; A second determination unit that determines whether there is a charging request to the battery; A third determination unit that determines whether the state of charge (SOC) of the battery is equal to or less than a determination value; And a notification control unit that executes a notification process for notifying a driver to stop when an affirmative determination is made by the first, second, and third determination units. A control device for a hybrid vehicle.

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