Travel support device

Abstract

To provide a technique capable of properly switching a travel mode of a hybrid vehicle according to the charging state of a battery.SOLUTION: When determining that a vehicle has entered an urban area EV control section (step S6; YES), a hybrid ECU 270 performs control of switching to an EV mode (step S8) after performing setting of lowering a recovery SOC level to a low recovery SOC level (step S7). When detecting that the vehicle has left the urban area EV control section, the hybrid ECU 270 determines that the execution of the urban area EV control should be terminated (step S9; YES), performs setting of returning to a normal recovery SOC level (step S10) and terminates the processing.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a driving support device for supporting the driving of a hybrid vehicle.

Background Art

[0002] Hybrid vehicles equipped with an engine and a motor as driving power sources have been widely popularized. In a hybrid vehicle, a state where the electric power stored in a battery that drives a motor or the like runs out (hereinafter, also referred to as a battery depletion state) may occur.

[0003] In view of such circumstances, a technique has been proposed to calculate a point at which the state of charge (SOC) of a battery becomes equal to or lower than a threshold value based on the electricity cost (power consumption per unit travel distance) uniquely obtained from vehicle type information (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when a hybrid vehicle enters a battery depletion state, the vehicle cannot return to the EV mode unless the SOC recovers to a set threshold level (for example, 20% or the like; hereinafter, the recovery SOC level).

[0006] Specifically, as shown in FIG. 1, when a hybrid vehicle 100 in a battery depletion state is switched to the battery charge (CHG) mode, the state of charge (SOC) of the battery gradually recovers. However, it cannot shift to the EV mode (using only the motor) unless it exceeds the set return SOC level. In this case, it has been pointed out that the driving mode has to be switched to the HV mode (using both the engine and the motor) for driving, which needlessly increases the SOC and deteriorates the fuel efficiency.

[0007] The present invention has been made in view of the above-described circumstances, and one of its objects is to provide a driving support technology capable of appropriately switching the driving mode of a hybrid vehicle according to the charge state of the battery.

Means for Solving the Problems

[0008] A driving support device according to an embodiment of the present invention is a driving support device for supporting the driving of a hybrid vehicle including a switching control unit that switches the driving mode of the vehicle to the EV mode when the charge state of the mounted battery satisfies the EV return condition, and includes an acquisition unit that acquires preview information related to the route of the vehicle, and a determination unit that determines whether or not the start condition or the end condition for driving support of the vehicle is satisfied based on the preview information. The switching control unit reduces or deletes the EV return condition when it is determined that the start condition for driving support is satisfied, and restores the EV return condition before reducing or deleting it when it is determined that the end condition for driving support is satisfied.

Effects of the Invention

[0009] According to the present invention, it becomes possible to appropriately switch the driving mode of a hybrid vehicle according to the charge state of the battery.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that since the basic concept, main hardware configuration, operating principle, and basic control methods of the control device for a vehicle are already known to those skilled in the art, detailed descriptions thereof will be omitted.

[0012] A. This Embodiment (Overview) FIG. 2 is an image diagram showing the features of this embodiment. As is clear from comparing FIG. 2 with FIG. 1, in this embodiment, when a predetermined condition is satisfied, the return SOC level is lowered (for example, to 16% etc.). Hereinafter, as an example of the predetermined condition, a specific section of an urban area where EV control is performed (hereinafter referred to as an urban EV control section) will be described, but it is not intended to be limited thereto. For convenience of explanation, the return SOC level before being lowered is referred to as the "normal return SOC level", and the return SOC level after being lowered is referred to as the "low return SOC level".

[0013] As shown in FIG. 2, when the hybrid vehicle 100 in a battery depletion state enters the urban EV control section, the return SOC level is lowered to the low return SOC level. At this point, since the SOC of the battery exceeds the set low return SOC level, the hybrid vehicle 100 can shift to the EV mode (using only the motor), and running control with better fuel efficiency than before becomes possible.

[0014] (Configuration) FIG. 3 is a diagram showing the schematic configuration of the driving support device 200 mounted on the hybrid vehicle according to this embodiment. The travel support device 200 includes a GPS 210, a navigation system 220, an air conditioner ECU 230, a sensor group 240, a display device 250, a battery actuator 260, a hybrid ECU 270, and the like.

[0015] The GPS (Global Positioning System) 210 is a device that detects the position of a vehicle based on signals transmitted from a plurality of GPS satellites. The navigation system 220 is a system that guides the host vehicle to a set destination and includes a map information database DB1. The navigation system 220 communicates with a traffic information management center 300 via a DCM (Data Communication Module) and the like. When a destination is set, the navigation system 220 sets a route based on the destination information, the current location information (the current position of the host vehicle) acquired by the GPS 210, and the information stored in the map information database DB1. Then, the navigation system 220 communicates with the traffic information management center 300 every predetermined time (for example, every 3 minutes or every 5 minutes) to acquire traffic information and the like, and generates route guidance information and preview information related to a section along the upcoming route based on the traffic information. The preview information includes, for example, information indicating the road type, presence or absence of congestion, section distance, speed limit, driving power, etc. of the upcoming section, and flag information indicating the presence or absence of an urban EV control section.

[0016] The air conditioner ECU 230 is configured as a microcomputer centered on a CPU, and includes a ROM, a RAM, a flash memory, an input port, an output port, a communication port, etc. in addition to the CPU. The air conditioner ECU 240 drives and controls an air conditioner compressor (not shown) in the air conditioning device so that the temperature inside the vehicle becomes the set temperature.

[0017] The sensor group 240 includes a vehicle speed sensor, an acceleration sensor, a brake sensor, a mode switch, etc. The vehicle speed sensor detects the vehicle speed based on the wheel speed, etc. The acceleration sensor detects the acceleration in the longitudinal direction of the vehicle and the acceleration in the lateral direction (sideways) of the vehicle. The accelerator sensor detects the accelerator opening corresponding to the depression amount of the driver's accelerator pedal, etc. The brake sensor detects the brake position as the depression amount of the driver's brake pedal, etc. The mode switch is a switch for switching various modes (for example, CHG mode, HV mode, EV mode, etc.).

[0018] The display device 250 is incorporated in, for example, the installation panel in front of the driver's seat and displays various information. The display device 250 has a driving state indicator and a meter that represent the driving state. The driving state indicator lights up the EV indicator and turns off the HV indicator when the motor is running, for example, and turns off the EV indicator and lights up the HV indicator when the vehicle is running in hybrid mode. The meter is incorporated in, for example, the installation panel in front of the driver's seat.

[0019] The battery actuator 260 detects the state of the battery 261, such as the terminal voltage, charge / discharge current, and battery temperature, and manages the battery 261 based on these. The battery actuator 260 obtains the state of charge (SOC) as the ratio of the remaining charge capacity to the total charge capacity based on the charge / discharge current and outputs it as SOC information to the hybrid ECU 270, etc. Also, the battery actuator 260 calculates the allowable maximum output power (output limit Wout), the allowable maximum input power (input limit Win), etc. based on the SOC of the battery 261, the battery temperature, etc. The battery 261 is configured as a rechargeable secondary battery, and for example, a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, etc. can be used.

[0020] The hybrid ECU 270 is configured as a microcomputer centered around a CPU, and in addition to the CPU, it is equipped with a ROM, a RAM, a flash memory, an input port, an output port, a communication port, and the like. The hybrid ECU 270 controls each part of the host vehicle and sets the driving mode and the like. Further, the hybrid ECU 270 sets the target operating point (target rotational speed and target torque) of the mounted engine and the torque command of the motor based on the set driving mode, various information supplied from the sensor group 240, the SOC information from the battery actuator 260, the output limit Wout, the input limit Win, and the like.

[0021] When the hybrid ECU 270 travels in the EV mode (electric driving), it sets the required driving force and required power based on the accelerator opening and vehicle speed from the sensor group 240, sets the torque command of the motor so as to output the required driving force and required power to the vehicle, and transmits the set torque command to an accelerator actuator (not shown). Further, the hybrid ECU 270 switches the setting of the SOC recovery level according to whether or not the vehicle in the battery depletion state has entered the urban EV control section (details will be described later).

[0022] When the hybrid ECU 270 travels in the HV mode (hybrid driving), it sets the target operating point of the engine and the torque command of the motor so as to output the required driving force and required power to the vehicle, and transmits the target operating point and the torque command to the accelerator actuator. Further, when the brake pedal is depressed, the hybrid ECU 270 sets the required braking force based on the brake position and vehicle speed from the sensor group 240, sets the torque command for regenerative control of the motor based on the required braking force and vehicle speed, sets the target braking force by the braking device, transmits the torque command to the accelerator actuator, and transmits the target braking force to the brake actuator. Each part of the driving support device 200 described above is mutually connected via a CAN (Controller Area Network) 280 or the like.

[0023] Next, the driving support control process executed by the hybrid ECU 270 will be described with reference to FIG. 4.

[0024] (2) Operation FIG. 4 is a flowchart showing the driving support control process. The hybrid ECU 270 determines whether the preview information generated by the navigation system 220 has been updated (step S1). As already described, the preview information includes, for example, information indicating the road type of the next section, the presence or absence of traffic congestion, the distance, the speed limit, information representing the driving power, and flag information indicating the presence or absence of an urban EV control section.

[0025] When the hybrid (acquisition unit) ECU 270 determines that the preview information has been updated (step S1; YES), it acquires the updated preview information from the navigation system 220 (step S2) and proceeds to step S3. On the other hand, when the hybrid ECU 270 determines that the preview information has not been updated (step S1; NO), it skips step S2 and proceeds to step S3.

[0026] The hybrid ECU (judgment unit) 270 determines whether urban EV control can be performed based on the preview information and the like (step S3). For example, the hybrid ECU 270 determines that urban EV control can be performed when the driving support device 200 is operating normally. Note that the conditions for determining that urban EV control can be performed (i.e., the start conditions for driving support) are not limited to the above, and conditions such as the driver instructing the execution of urban EV control or the vehicle being driven on route may be added.

[0027] When the hybrid ECU 270 determines that urban EV control can be performed (step S3; YES), it refers to the flag information indicating the presence or absence of an urban EV control section included in the preview information, and determines whether there is an urban EV control section in the upcoming driving route (step S4). When the hybrid ECU 270 determines that there is an urban EV control section in the upcoming driving route (step S4; NO), it calculates the energy required for driving in the urban EV control section (hereinafter referred to as EV driving energy) Egeo (step S5). The hybrid ECU 270 can calculate the EV driving energy Egeo by using, for example, the distance and speed of the urban EV control section included in the preview information.

[0028] After calculating the EV driving energy Egeo, the hybrid ECU 270 determines whether the vehicle has entered the urban EV control section based on the preview information and the route guidance information (step S6).

[0029] <When entering the urban EV control section> When the hybrid ECU (switching control unit) 270 determines that it has entered the urban EV control section (step S6; YES), after setting the return SOC level to the low return SOC level (step S7), it performs control to switch to the EV mode (step S8).

[0030] Thereafter, the hybrid ECU (judgment unit) 270 determines whether the urban EV control should be terminated based on the preview information and the route guidance information (step S9). For example, when the hybrid ECU 270 detects that the vehicle has exited the urban EV control section, it determines that the urban EV control should be terminated (step S9; YES). Then, the hybrid ECU (switching control unit) 270 sets the lowered return SOC level back to the normal return SOC level (step S10) and ends the process.

[0031] On the other hand, when the hybrid ECU 270 determines that the execution of the urban EV control should not be terminated (step S9; NO), it returns to step S1 and repeatedly executes the above-described series of processes. Note that the conditions for determining that the execution of the urban EV control should be terminated (i.e., the end conditions for driving support) are not limited to the above, and may be conditions such as the driver instructing the end of the execution of the urban EV control, or the vehicle is running outside the route, etc.

[0032] <When not entering the urban EV control section> When the hybrid ECU 270 determines that it has not entered the urban EV control section (step S6; NO), based on the SOC information supplied from the battery actuator 260, it determines whether the current battery remaining amount Erem is sufficiently larger than the EV driving energy Egeo (step S11; see Equation (1)). Erem > Egeo + α ···(1) α; surplus

[0033] When the hybrid ECU 270 determines that the current battery remaining amount Erem is sufficiently larger than the EV driving energy Egeo (step S11; YES), it proceeds to step S7 and sets the return SOC level to be lowered to the low return SOC level.

[0034] On the other hand, when the hybrid ECU 270 determines that the current battery remaining amount Erem is not sufficiently larger than the EV driving energy Egeo (step S11; NO), it determines whether the current battery remaining amount Erem is less than or equal to the EV driving energy Egeo (step S12; see Equation (2)). Erem ≦ Egeo ···(2)

[0035] When the hybrid ECU 270 determines that the current battery remaining amount Erem is equal to or less than the EV driving energy Egeo (step S12; YES), it performs control to switch to the battery charge (CHG) mode in order to fully charge the battery (step S13). Thereafter, the hybrid ECU 270 proceeds to step S9 and determines whether to end the urban EV control. However, the subsequent processing has already been described and will be omitted here.

[0036] On the other hand, when the hybrid ECU 270 determines that the current battery remaining amount Erem is not less than the EV driving energy Egeo (step S12; NO), it determines whether it can be said that the current battery remaining amount Erem is not sufficiently larger than the EV driving energy Egeo (step S14; see Equation (3)). Egeo < Erem ≦ Egeo + α ···(3)

[0037] When the hybrid ECU 270 determines that it cannot be said that the current battery remaining amount Erem is sufficiently larger than the EV driving energy Egeo (step S14; YES), it performs control to switch to the HV mode in order to maintain the state of charge (SOC) of the battery while driving (step S15). Thereafter, the hybrid ECU 270 proceeds to step S9 and determines whether to end the urban EV control. However, the subsequent processing has already been described and will be omitted here.

[0038] As described above, according to the present embodiment, when a hybrid vehicle in a battery depletion state enters the urban EV control section or even before entering the urban EV control section, if the current battery remaining amount is sufficient, a setting is made to lower the return SOC level. At this time, since the SOC of the battery exceeds the low return SOC level, the vehicle can be shifted to the EV mode (using only the motor), and fuel-efficient driving control can be achieved as compared with the conventional case.

[0039] B. Modification Example The present invention is not limited to the above-described embodiments, and can be implemented in various other forms without departing from the gist of the present invention. Therefore, the above embodiments are merely illustrative in all respects and should not be construed in a limiting sense. For example, each of the above-described processing steps can be arbitrarily changed in order or executed in parallel as long as there is no contradiction in the processing content.

[0040] In this embodiment, when it is determined that the vehicle has entered the urban EV control section, etc., the setting is made to lower the return SOC level to the low return SOC level. However, for example, the setting of the return SOC level itself may be deleted. For the deleted return SOC level, for example, when it is determined that the vehicle has exited the urban EV control section, etc., the return SOC level may be restored (revived).

[0041] Also, when it is determined that urban EV control can be implemented (that is, it is determined that the start condition for driving support is satisfied), the return SOC level may be lowered to the low return SOC level regardless of whether the vehicle has entered the urban EV control section.

[0042] Also, the threshold value of the low return SOC level itself may be set. For example, if the threshold value of the low return SOC level is too low, there is a possibility that even if the SOC value of a vehicle in a battery depletion state exceeds the low return SOC level, it will immediately fall below the low return SOC level. Therefore, the threshold value of the low return SOC level (for example, 18% etc.) may be set so that the state of exceeding the low return SOC level can be maintained for a certain period of time or more (that is, the EV mode can be continued).

[0043] C. Others The program for implementing the driving support control process described in this specification may be stored in a recording medium. By using this recording medium, the above program can be installed in the hybrid ECU 270. Here, the recording medium storing the above program may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, but may be a recording medium such as a CD-ROM, for example.

Explanation of Symbols

[0044] 100…Hybrid vehicle, 200…Driving support device, 210…GPS, 220…Navigation system, 230…Air conditioner ECU, 240…Sensor group, 250…Display device, 260…Battery actuator, 261…Battery, 270…Hybrid ECU, 300…Traffic information management center, DB1…Map information database.

Claims

【Claim 1】 A driving support device for supporting the driving of a hybrid vehicle, comprising a switching control unit that switches the driving mode of the vehicle to an EV mode when the state of charge of the mounted battery satisfies the EV return condition, an acquisition unit that acquires preview information related to the route of the vehicle, and a determination unit that determines whether or not the start condition or the end condition of the driving support of the vehicle is satisfied based on the preview information, wherein the switching control unit lowers or deletes the EV return condition when it is determined that the start condition of the driving support is satisfied, and returns the EV return condition to before it is lowered or deleted when it is determined that the end condition of the driving support is satisfied, the start condition of the driving support is that urban EV control is feasible, the determination unit determines whether or not there is an urban EV control section in the upcoming driving route based on the preview information, the switching control unit, when it is determined by the determination unit that there is an urban EV control section and the vehicle has not yet entered the urban EV control section, and when it is determined based on the SOC information that the current battery remaining amount is greater than a predetermined amount than the EV driving energy required for driving in the urban EV control section, lowers or deletes the EV return condition. Driving support device.

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