Control device of hybrid vehicle

Abstract

To provide a control device of a hybrid vehicle that can secure an opportunity for forcibly driving a starter.SOLUTION: A control device of a hybrid vehicle, which comprises an engine as a running power source, a motor that can start the engine and also can act as a running power source, and a starter that can start the engine, is provided with a determining part that determines whether a driver has instructed for forcibly driving the starter or not and a driving control part that forcibly drives the starter, when the determining part determines that the driver has instructed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Hybrid vehicles are known that include an engine as a power source for running the vehicle, a motor that can start the engine and also serve as a power source for running the vehicle, and a starter that can start the engine. In such hybrid vehicles, because the engine can be started by the motor, there is a risk that the starter will not be driven for a long period of time, causing corrosion of the starter. Therefore, there is a technology that prevents corrosion of the starter by forcibly driving the starter when a predetermined condition is met (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-167625 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above technique, the starter is not forcibly driven if the predetermined condition is not met.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for a hybrid vehicle that ensures an opportunity for forced driving of the starter. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a hybrid vehicle that is equipped with an engine as a driving power source, a motor that can start the engine and also as a driving power source, and a starter that can start the engine, the control device comprising: a judgment unit that judges whether or not the driver has instructed the starter to be forcibly driven; and a drive control unit that forcibly drives the starter if the judgment unit judges yes. [Effects of the Invention]

[0007] It is possible to provide a control device for a hybrid vehicle that ensures an opportunity for forced driving of the starter. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] 4 is a flowchart illustrating a starter forced drive control. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Hybrid vehicle configuration] FIG. 1 is a schematic diagram of a hybrid vehicle 1. In the hybrid vehicle 1, a clutch 30, a motor 40, and a transmission 50 are provided in this order in a power transmission path from an engine 10 to drive wheels 70. The engine 10 and the motor 40 are mounted as a drive source for running the hybrid vehicle 1. The engine 10 is, for example, a gasoline engine, but may also be a diesel engine. 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 power transmission path. When the clutch 30 receives a supply of hydraulic pressure, it changes from a released state to an engaged state, connecting the power transmission between the engine 10 and the motor 40. When the hydraulic pressure supply is stopped, the clutch 30 changes to a released state, cutting off the power transmission between the engine 10 and the motor 40.

[0011] The motor 40 is connected to the high-voltage battery 90 via the PCU 80. The motor 40 functions as a power source for driving the hybrid vehicle 1 in response to power supplied from the high-voltage battery 90. The motor 40 also functions as a generator that charges the high-voltage battery 90 in response to power transmitted from the engine 10 and the drive wheels 70.

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

[0013] An auxiliary battery 92 is connected to the PCU 80. The PCU 80 steps down the DC voltage from the high-voltage battery 90 and supplies it to the auxiliary battery 92. The rated voltage of the auxiliary battery 92 is lower than that of the high-voltage battery 90. The auxiliary battery 92 is charged by receiving a supply of DC voltage from the PCU 80.

[0014] The engine 10 is provided with a starter 12. The starter 12 is a motor that cranks the engine 10 when the engine 10 is started. The starter 12 is controlled by an ECU 100, which will be described later. The starter 12 is driven by power from an auxiliary battery 92. The auxiliary battery 92 is connected to the PCU 80. The power from the auxiliary battery 92 is also supplied to auxiliary equipment (not shown).

[0015] 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 that includes a processing circuit that performs various types of calculations related to vehicle driving control, and a memory that stores control programs and data. The ECU 100 is an example of a vehicle control device, and functionally realizes a determination unit and a drive control unit, which will be described in detail later.

[0016] The ECU 100 drives the hybrid vehicle in either a motor driving mode or a hybrid driving mode. In the motor driving mode, the ECU 100 stops the engine 10, disengages the clutch 30, and drives the vehicle using the power of the motor 40. In the hybrid driving mode, the clutch 30 is engaged and the vehicle drives using at least the power of the engine 10. In addition, in the hybrid driving mode, the drive of the engine 10 can be assisted by the output of the motor 40.

[0017] A display unit 110 and an input unit 112 are connected to the ECU 100. The display unit 110 is, for example, a display provided on an instrument panel of the hybrid vehicle 1. The input unit 112 is a touch panel or operation buttons provided on the instrument panel. The display unit 110 is controlled by the ECU 100, and displays a message when the starter 12 is being forcibly driven, as will be described in detail later. As will be described in detail later, the driver can forcibly drive the starter 12 by operating the input unit 112. In addition, the driver can set the drive period of the engine 10 that has been started by forcibly driving the starter 12, by operating the input unit 112. An ignition switch (not shown) is connected to the ECU 100.

[0018] A large-capacity capacitor 120 is connected to the ECU 100. The large-capacity capacitor 120 is charged by power supplied from the auxiliary battery 92 while the starter 12 is being forcibly driven. After the ignition is turned off, no power is supplied to the large-capacity capacitor 120, and the large-capacity capacitor 120 naturally discharges. As the large-capacity capacitor 120 naturally discharges, the voltage value of the large-capacity capacitor 120 decreases.

[0019] The ECU 100 forcibly drives the starter 12 when a predetermined condition is met. The predetermined condition is as follows: (1) The voltage value of the large-capacity capacitor 120 is equal to or less than a threshold value; (2) The cumulative time is equal to or greater than the specified time. In condition (1), if the voltage value of the large-capacity capacitor 120 is equal to or lower than the threshold value, it is considered that the period during which the ignition is off, i.e., the period during which the hybrid vehicle 1 is stopped, is long, and the starter 12 is forcibly driven.

[0020] The cumulative time in condition (2) is the accumulated time from the start of the engine 10 by the starter 12 to the next start of the engine 10 by the starter 12. If the cumulative time exceeds a predetermined time, the starter 12 is forcibly driven as it has not been driven for a long period of time. The cumulative time is measured as follows: The elapsed time is measured by a soak timer during the ignition-off period, and the elapsed time is measured by a time counter during the ignition-on period. The sum of the elapsed time measured by the soak timer and the elapsed time measured by the time counter is calculated as the cumulative time. The soak timer is built into the ECU 100, and power is supplied from the auxiliary battery 92 even while the ignition is off. The time counter is functionally realized by the ECU 100.

[0021] [Starter forced drive control] FIG. 2 is a flowchart illustrating the starter forced drive control. This control is repeatedly executed while the ignition is on. The ECU 100 determines whether or not the driver has issued a command to forcibly drive the starter 12 (step S1). If the answer is No in step S1, this control ends. Step S1 is an example of processing executed by the determination unit.

[0022] If the answer to step S1 is Yes, the ECU 100 forcibly drives the starter 12 (step S2), thereby starting the engine 10. Step S2 is an example of a process executed by the drive control unit.

[0023] Next, the ECU 100 notifies the driver that the starter 12 has been forcibly driven by displaying a message on the display unit 110 (step S3). This allows the driver to confirm that the starter 12 has been forcibly driven. The notification to the driver may be made, for example, through a speaker mounted on the hybrid vehicle 1.

[0024] Next, the ECU 100 starts charging the auxiliary battery 92 based on the start of the engine 10 (step S4). Charging of the auxiliary battery 92 starts based on the power generated by the motor 40 when the engine 10 is driven, or the power of an alternator that converts part of the power of the engine 10 into electric power. This prevents a decrease in the charge amount of the auxiliary battery 92.

[0025] Next, ECU 100 turns on the forced drive flag (step S5). Next, ECU 100 starts charging large-capacity capacitor 120 based on the forced drive flag being on (step S6), and resets the accumulated time (step S7). Because charging of large-capacity capacitor 120 starts when starter 12 is forcibly driven, the accuracy of determining whether condition (1) is met is improved. Furthermore, because the accumulated time is reset when starter 12 is forcibly driven, the accuracy of determining whether condition (2) is met is improved.

[0026] Next, ECU 100 turns off the forced drive flag (step S8), and terminates charging of large-capacity capacitor 120 based on the fact that the forced drive flag is off (step S9).

[0027] Next, the ECU 100 stops the engine 10 after the driving period of the engine 10 set by the driver via the input unit 112 has elapsed (step S10). Next, the ECU 100 ends charging of the auxiliary battery 92 based on the stopping of the engine 10 (step S11).

[0028] Next, the ECU 100 notifies the driver that the forced driving of the starter 12 has ended and the engine 10 has stopped by displaying a message on the display unit 110 (step S12). The notification to the driver may be made, for example, through a speaker mounted on the hybrid vehicle 1.

[0029] Next, the ECU 100 determines whether or not an ignition-off command has been issued (step S13). If the result of step S13 is No, step S13 is executed again. If the result of step S13 is Yes, the ECU 100 starts counting the elapsed time using a soak timer (step S14) and stops the system (step S15).

[0030] As described above, the starter 12 can be forcibly driven based on the driver's instruction, thereby ensuring opportunities for forcibly driving the starter 12.

[0031] In the above embodiment, the hybrid vehicle 1 is illustrated as having the engine 10 and the motor 40 as a driving power source, but is not limited to this. For example, the hybrid vehicle may be equipped with an engine and first and second motors as driving power sources, and further equipped with a planetary gear mechanism that transmits the power of these motors to the drive wheels.

[0032] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0033] 1 Hybrid vehicle 10 Engine 12 Starter 40 Motor 100 ECU (control unit, determination unit, drive control unit) 110 Display section 112 Input section

Claims

[Claim 1] A control device for a hybrid vehicle including an engine as a driving power source, a motor capable of starting the engine and also serving as a driving power source, and a starter capable of starting the engine, a determination unit that determines whether or not a driver has issued an instruction to forcibly drive the starter; a drive control unit that forcibly drives the starter when the determination unit makes a positive determination.

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