JP7615792B2 - Hybrid vehicle control device - Google Patents

Description

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

Patent document 1 discloses a technology that switches to a motor driving mode in which the vehicle runs only on the motor when the accelerator pedal operation amount is below a predetermined value, and switches to hybrid driving in which the engine is also used when the accelerator pedal operation amount exceeds the predetermined value.

JP 2011-140275 A

However, with conventional technology such as that proposed in Patent Document 1, when traveling on a flat road, for example when there is an uphill road in the direction of travel and torque is required, in a situation where it is desired to start the engine in advance, the driver must depress the accelerator pedal more than a certain amount in order to start the engine. Therefore, in cases where it is desired to start the engine in advance as described above, the driver must depress the accelerator pedal even in situations where it is not necessary to depress the accelerator pedal much, and there is a possibility that the engine will not start as intended by the driver.

In addition, some vehicles are equipped with a switch on the instrument panel that prevents the engine from automatically stopping, but this requires an operation separate from driving operations while driving, which poses the problem of low operability.

The present invention has been made to solve the above problems, and aims to provide a control device for a hybrid vehicle that can improve the operability of prohibiting automatic engine stop.

The control device for a hybrid vehicle according to the present invention includes an engine, an electric motor, and an accelerator pedal, and when the accelerator pedal is depressed to a predetermined amount or less during hybrid driving in which the vehicle runs on power output from the engine or the engine and the electric motor, the control device automatically stops the engine and transitions to motor driving in which the vehicle runs on power from the electric motor. The accelerator pedal is provided with a sensor that detects contact with a part of the accelerator pedal, and has a control unit that prohibits the automatic stopping of the engine when the contact is detected by the sensor.

The present invention provides a control device for a hybrid vehicle that can improve the operability of prohibiting automatic engine shutdown.

FIG. 1 is a schematic diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a conceptual diagram for explaining the arrangement of contact sensors in one embodiment of the present invention, in which (a) shows an example of a state in which the accelerator pedal is depressed in a situation in which it is not necessary to depress the accelerator pedal heavily, and (b) shows an example of a state in which the accelerator pedal is depressed in a situation in which it is necessary to depress the accelerator pedal heavily. FIG. 3 is a flow chart showing the automatic engine stop control operation of the control device for a hybrid vehicle according to one embodiment of the present invention.

A control device for a hybrid vehicle according to one embodiment of the present invention includes an engine, an electric motor, and an accelerator pedal, and when the accelerator pedal is depressed to a predetermined amount or less during hybrid driving, in which the vehicle runs on power output from the engine or the engine and the electric motor, the control device automatically stops the engine and transitions to motor driving, in which the vehicle runs on power from the electric motor. The control device for a hybrid vehicle according to one embodiment of the present invention is characterized in that the accelerator pedal is provided with a sensor that detects contact with a part of the accelerator pedal, and has a control unit that prohibits automatic stopping of the engine when contact is detected by the sensor. As a result, the control device for a hybrid vehicle according to one embodiment of the present invention can improve operability for prohibiting automatic stopping of the engine.

Below, a hybrid vehicle equipped with a hybrid vehicle control device according to one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the hybrid vehicle 1 includes an engine 2, a clutch 3, a high-voltage motor 4, drive wheels 5, an inverter 6, a high-voltage battery 7, an ISG 8, a starter 9, a low-voltage battery 10, and an ECU (Electronic Control Unit) 11 as a control unit.

Engine 2 has multiple cylinders. In this embodiment, engine 2 is configured to perform a series of four strokes for each cylinder, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Engine 2 generates power by performing a series of four strokes.

The clutch 3 is, for example, a normally closed type dry clutch. The clutch 3 connects or disconnects the power transmission path between the engine 2 and the high voltage motor 4. A transmission (not shown) is provided in the power transmission path between the clutch 3 and the high voltage motor 4.

The transmission provided in the power transmission path between the clutch 3 and the high-voltage motor 4 may be a manual transmission such as an MT (Manual Transmission), or an automatic transmission such as a CVT (Continuously Variable Transmission), an AT (Automatic Transmission), a DCT (Dual-Clutch Transmissions), or an AGS (Auto Gear Shift).

The high-voltage motor 4 is connected to the drive wheels 5 so that it can transmit power to them. The high-voltage motor 4 functions as an electric motor, and drives the drive wheels 5 with power supplied from a high-voltage battery 7 via an inverter 6. The high-voltage battery 7 is composed of a rechargeable secondary battery, and is, for example, a lithium-ion battery capable of generating an output voltage of 100 V.

The high-voltage motor 4 also functions as a generator, converting the power generated by the engine 2 or the driving force of the drive wheels 5 into electricity and supplying it to the high-voltage battery 7 via the inverter 6, thereby charging the high-voltage battery 7.

The ISG8 functions as an electric motor and restarts the engine 2 from a stopped state. The ISG8 can also assist the running of the hybrid vehicle 1. The starter 9 provides the rotational force to the engine 2 when starting it.

The ISG 8 and the starter 9 are driven by power supplied from a low-voltage battery 10. The low-voltage battery 10 is composed of a rechargeable secondary battery, for example a lead battery capable of generating an output voltage of 12 V.

The ECU 11 is composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports, output ports, and a communication module.

The ROM of this computer unit stores various constants, maps, etc., as well as a program that causes the computer unit to function as the ECU 11.

In other words, the CPU uses the RAM as a working area to execute the programs stored in the ROM, causing this computer unit to function as the ECU 11 in this embodiment.

The input port of the ECU 11 is connected to various sensors including an accelerator opening sensor 13 that detects the amount of operation of the accelerator pedal 12 (hereinafter also referred to as "accelerator opening") and a contact sensor 14 that detects contact with a part of the accelerator pedal 12. The output port of the ECU 11 is connected to various control objects including the inverter 6, ISG 8, and starter 9.

The contact sensor 14 is, for example, composed of a piezoelectric element. As shown in FIG. 2(a), when the driver does not need to depress the accelerator pedal 12 much, the driver does not depress the accelerator pedal 12 all the way, and as shown in FIG. 2(b), when the driver needs to depress the accelerator pedal 12 much, the driver tends to depress the accelerator pedal 12 all the way. Therefore, the contact sensor 14 is provided in the front of the accelerator pedal 12. The front of the accelerator pedal 12 refers to the toe side of the driver's foot who depresses the accelerator pedal 12, or the upper side in the example shown in FIG. 2. The contact sensor 14 may be provided in a position where the driver does not normally depress the accelerator pedal 12. For example, a protruding piece is provided on the left, right, or upper side of the upper end side of the accelerator pedal 12, and the contact sensor 14 is provided on the protruding piece.

In FIG. 1, the ECU 11 controls the engine 2 and the high-voltage motor 4 by outputting control signals to various control objects connected to the output ports in response to detection signals input from various sensors connected to the input ports.

The ECU 11 switches the driving mode between hybrid driving, in which the vehicle runs on power output from the engine 2 or the engine 2 and the high-voltage motor 4, and motor driving, in which the vehicle runs on power output from the high-voltage motor 4.

For example, when the accelerator pedal 12 is depressed to a predetermined amount or less during hybrid driving, the ECU 11 automatically stops the engine 2 and switches the driving mode to motor driving. The predetermined amount is an appropriate value determined through verification so that the required torque can be output while maintaining high fuel efficiency.

When the contact sensor 14 detects contact during hybrid driving, the ECU 11 prohibits the automatic stopping of the engine 2. In other words, when the contact sensor 14 detects contact during hybrid driving, the ECU 11 prohibits the automatic stopping of the engine 2, and allows the automatic stopping of the engine 2 while the contact sensor 14 does not detect contact.

Therefore, for example, in a situation where the driver does not want the engine 2 to automatically stop while the hybrid vehicle 1 is traveling on a flat road, such as when it is known that torque is required due to an uphill road in the direction of travel of the hybrid vehicle 1 during hybrid driving, the driver can prohibit the engine 2 from automatically stopping by contacting the contact sensor 14.

In addition, when the contact sensor 14 detects contact for a predetermined time (e.g., 3 seconds) or more during hybrid driving, the ECU 11 sets the automatic stop prohibition state to prohibit automatic stopping of the engine 2 until the hybrid vehicle 1 comes to a stop, even if the contact sensor 14 no longer detects contact. As a result, even if the contact sensor 14 does not continue to detect contact, the automatic stop of the engine 2 can be prohibited for a long period of time by setting the automatic stop prohibition state.

In addition, to allow the driver to cancel the automatic stop prohibition state at his/her discretion, the ECU 11 cancels the automatic stop prohibition state if the contact sensor 14 detects another contact while the automatic stop prohibition state is in effect.

The engine automatic stop control operation of the ECU 11 configured as above will be described with reference to FIG. 3. Note that the engine automatic stop control operation described below is repeatedly executed at a predetermined time interval during hybrid driving.

As shown in FIG. 3, in S1, the ECU 11 determines whether or not contact has been detected by the contact sensor 14. If it is determined in S1 that contact has been detected by the contact sensor 14, the ECU 11 executes the process of S2. If it is determined in S1 that contact has not been detected by the contact sensor 14, the ECU 11 executes the process of S6.

In S2, if automatic stopping of the engine 2 is not prohibited, the ECU 11 prohibits automatic stopping of the engine 2. After executing the process of S2, the ECU 11 executes the process of S3.

In S3, the ECU 11 determines whether the period during which contact is detected by the contact sensor 14 is equal to or longer than a predetermined time. If it is determined in S3 that the period during which contact is detected by the contact sensor 14 is equal to or longer than the predetermined time, the ECU 11 executes the process of S4. If it is determined in S3 that the period during which contact is detected by the contact sensor 14 is not equal to or longer than the predetermined time, the ECU 11 executes the process of S5.

In S4, if the automatic stop prohibition state is not set, the ECU 11 sets the automatic stop prohibition state. When the hybrid vehicle 1 stops, the ECU 11 cancels the automatic stop prohibition state. After executing the process of S4, the ECU 11 ends the engine automatic stop control operation. In S5, if the automatic stop prohibition state is set, the ECU 11 cancels the automatic stop prohibition state. After executing the process of S5, the ECU 11 ends the engine automatic stop control operation.

In S6, the ECU 11 determines whether or not the automatic stop prohibition state is in effect. If it is determined in S6 that the automatic stop prohibition state is in effect, the ECU 11 ends the engine automatic stop control operation. This maintains the automatic stop prohibition state. If it is determined in S6 that the automatic stop prohibition state is not in effect, the ECU 11 executes the process of S7. In S7, the ECU 11 permits automatic stopping of the engine 2. After executing the process of S7, the ECU 11 ends the engine automatic stop control operation.

As described above, the control device for a hybrid vehicle according to this embodiment can prohibit the automatic stopping of the engine when contact is detected by the contact sensor 14 provided on the accelerator pedal 12, regardless of the accelerator opening. This allows the automatic stopping of the engine 2 to be prohibited simply by changing the position at which the accelerator pedal 12 is depressed, thereby improving the operability of prohibiting the automatic stopping of the engine 2.

In addition, the control device for the hybrid vehicle according to this embodiment can prohibit the automatic stopping of the engine when contact is detected by the contact sensor 14 provided on the accelerator pedal 12, regardless of the accelerator opening degree, and can control the engine 2 by distinguishing between a situation in which the accelerator pedal 12 is depressed and a situation in which the required torque is not high, i.e., the accelerator pedal 12 is not depressed.

In addition, the control device for the hybrid vehicle according to this embodiment can prohibit the automatic stopping of the engine simply by changing the position where the accelerator pedal 12 is depressed. This makes it possible to prohibit the automatic stopping of the engine 2 with a simple operation while driving, compared to a case where a switch for prohibiting the automatic stopping of the engine 2 is provided on the instrument panel.

In addition, the control device for the hybrid vehicle according to this embodiment can more accurately detect the driver's intention and prohibit the automatic engine stop in situations where the accelerator pedal 12 does not need to be depressed much by providing a contact sensor 14 at a position where the accelerator pedal 12 is not depressed.

The control device for the hybrid vehicle according to this embodiment prohibits automatic stopping of the engine 2 while contact is detected by the contact sensor 14, and permits automatic stopping of the engine 2 while contact is not detected by the contact sensor 14. Therefore, while contact is detected by the contact sensor 14, automatic stopping of the engine 2 is prohibited assuming that the driver intends to prohibit automatic stopping of the engine 2, thereby making it possible to prohibit automatic stopping of the engine 2 in accordance with the driver's intention.

In addition, the control device for the hybrid vehicle according to this embodiment can set the automatic stop prohibition state to prohibit the engine from automatically stopping until the hybrid vehicle 1 comes to a stop, eliminating the need for the driver to keep touching the contact sensor 14, further improving operability.

In addition, the control device for the hybrid vehicle according to this embodiment can release the automatic stop prohibition state when the contact sensor 14 detects another contact while the automatic stop prohibition state is in effect, so that even if the driver's intentions change, the engine 2 can be controlled in accordance with the driver's intentions.

In this embodiment, an example in which the contact sensor 14 is configured using a piezoelectric element has been described, but the contact sensor 14 may be configured using other components, such as a momentary type push button, as long as it detects contact with a part of the accelerator pedal 12.

In addition, the control device for the hybrid vehicle according to this embodiment may be provided with an optical sensor consisting of a light-emitting element and a light-receiving element instead of the contact sensor 14. In this case, a light-emitting element is provided either above the accelerator pedal 12 or in front of the accelerator pedal 12, and a light-receiving element is provided on the other side. When the light emitted from the light-emitting element is no longer received by the light-receiving element, the ECU 11 determines that contact with a part of the accelerator pedal 12 has been detected, and prohibits the automatic stop of the engine 2.

In addition, in this embodiment, the condition for prohibiting automatic stopping of the engine 2 is that the contact sensor 14 detects contact. However, for example, the condition for prohibiting automatic stopping of the engine 2 may be that the contact sensor 14 detects contact and the accelerator opening at that time is equal to or less than a predetermined value. In this case, it is possible to reliably detect that the driver has deliberately moved his/her foot to the position of the contact sensor 14 when the driver is not depressing the accelerator pedal 12. This makes it possible to accurately grasp the driver's intention.

In addition, the control device for the hybrid vehicle according to this embodiment only needs to be able to detect a slight change in the driver's driving operation in order to prohibit the automatic stopping of the engine 2, and may, for example, prohibit the automatic stopping of the engine 2 according to the strength with which the driver grips the steering wheel (not shown).

Although an embodiment of the present invention has been disclosed, it is apparent that modifications may be made by one of ordinary skill in the art without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 Hybrid vehicle 2 Engine 4 High voltage motor (electric motor)
11 ECU (control unit)
12 Accelerator pedal 14 Contact sensor

Claims (5)

The engine,
An electric motor;
An accelerator pedal;
A control device for a hybrid vehicle, which automatically stops the engine and transitions to a motor driving mode in which the vehicle runs on power output from the engine or the engine and the electric motor when an amount of depression of the accelerator pedal is equal to or less than a predetermined amount during hybrid driving in which the vehicle runs on power output from the engine or the engine and the electric motor,
The accelerator pedal is provided with a sensor that detects contact with a part of the accelerator pedal,
A control device for a hybrid vehicle, comprising: a control unit that inhibits an automatic stop of the engine when the contact is detected by the sensor. The control device for a hybrid vehicle according to claim 1, characterized in that the sensor is provided in front of the accelerator pedal. The control device for a hybrid vehicle according to claim 1 or 2, characterized in that the control unit prohibits the automatic stop of the engine while the contact is detected by the sensor, and allows the automatic stop of the engine while the contact is not detected by the sensor. The control device for a hybrid vehicle according to any one of claims 1 to 3, characterized in that, when the contact is detected by the sensor for a predetermined period of time or more while the hybrid vehicle is traveling, the control unit sets an automatic stop prohibition state in which the automatic stop of the engine is prohibited until the hybrid vehicle is stopped, even if the contact is no longer detected by the sensor. 5. The control device for a hybrid vehicle according to claim 4, wherein the control unit cancels the automatic stop prohibition state when the contact is detected again by the sensor during the automatic stop prohibition state.

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