阅读说明：本技术 具有变道防撞系统的混合动力车辆 (Hybrid vehicle with lane-changing collision avoidance system ) 是由 李解 于 2021-03-03 设计创作，主要内容包括：本发明涉及一种混合动力车辆,尤其涉及一种具有变道防撞系统的混合动力车辆。根据本发明的混合动力车辆可包括检测单元、信息处理单元、速度控制单元、警告单元和转向控制单元,根据本发明的混合动力车辆可提高变道安全性。(The present disclosure relates to hybrid vehicles, and particularly to a hybrid vehicle with a lane-change collision avoidance system. The hybrid vehicle according to the present invention may include a detection unit, an information processing unit, a speed control unit, a warning unit, and a steering control unit, and may improve lane change safety.)

1. A hybrid vehicle, characterized in that the hybrid vehicle includes a lane change collision avoidance system, the lane change collision avoidance system comprising:

a detection unit (21) that determines a first distance D1 between the host vehicle (10) and a first obstacle vehicle (11) in an adjacent left lane, a second distance D1 between the host vehicle (10) and a second obstacle vehicle (12) in an adjacent left lane, a third distance D3 between the host vehicle (10) and a third obstacle vehicle (13) in an adjacent right lane, and a fourth distance D4 between the host vehicle (10) and a fourth obstacle vehicle (14) in an adjacent right lane, and that detects a vehicle speed V0 of the host vehicle, a first vehicle speed V1 of the first obstacle vehicle (11), a second vehicle speed V2 of the second obstacle vehicle (12), a third vehicle speed V3 of the third obstacle vehicle (13), and a fourth vehicle speed V4 of the fourth obstacle vehicle (14), wherein the first obstacle vehicle (11) is located ahead of the second obstacle vehicle (12), and the third obstacle vehicle (13) is located ahead of the fourth obstacle vehicle (14),

an information processing unit (22) that receives the information of the host vehicle, the first obstacle vehicle, to the fourth obstacle vehicle sent by the detection unit (21) and determines whether to perform a lane change operation based on the information,

a speed control unit (23) that receives the engine information, the motor information, and the battery information transmitted by the detection unit (21) and calculates an expected lane change vehicle speed,

a warning unit (24) that displays lane change related information to the driver,

a steering control unit (25) that receives a driver's steering intention and indicates a lane change direction;

the lane-changing anti-collision system executes lane-changing operation by the following method:

in step S300, it is determined whether the driver intends to make a lane change based on a signal instructed by a steering control unit (25), and when it is determined that the driver intends to perform a steering operation, step S301 is performed,

in step S301, the type of steering indicated by the steering control unit (25) is judged, and if it is determined that the driver intends to change lane to the left, step S303 is executed,

in step S303, the presence or absence of a first obstacle vehicle (11) and a second obstacle vehicle (12) is detected, step S316 is executed if the first obstacle vehicle (11) and the second obstacle vehicle (12) are not detected, step S305 is executed if the first obstacle vehicle (11) and the second obstacle vehicle (12) are detected,

in step S305, a first distance D1 between the host vehicle (10) and the first obstacle vehicle (11) and a second distance D2 between the host vehicle (10) and the second obstacle vehicle (12) are determined, then step 307 is performed,

in step 307, comparing the first distance D1 with the first safe distance S1 and the second distance D2 with the safe distance S2, the first safe distance S1 and the second safe distance S2 are calculated by the following formula:

S1=(V1-V0)*T+D1+∆S’，S2=(V2-V0)*T+D2+∆S’

wherein T is the expected time of the master vehicle (10) to change lanes, Δ S' is a first safety threshold,

if the first distance D1 is greater than the first safe distance S1 and the second distance D2 is greater than the second safe distance S2, step 309 is performed, otherwise, step 305 is performed,

in step 309, the speed V0 of the host vehicle (10), the first speed V1 of the first obstacle vehicle (11) and the second speed V2 of the second obstacle vehicle (12) are detected, and then step 311 is executed,

comparing the second speed V2 of the second obstacle vehicle (12) with the road speed limit of the current lane, if the second speed V2 reaches the road speed limit, alerting the driver, if the second speed V2 is less than the road speed limit, at step S311, executing step S313,

in step S313, an expected lane change vehicle speed and a corresponding lane change time are determined according to the first distance D1, the second distance D2, the speed V0, the first speed V1, and the second speed V2, and then, step S315 is performed,

in step S315, engine state information, motor state information, and battery state information of the host vehicle are received, if the expected lane change vehicle speed is greater than the predetermined vehicle speed or the battery level is less than a predetermined value, the lane change operation is implemented using the engine, if the expected lane change vehicle speed is less than the predetermined vehicle speed and the battery level is greater than the predetermined value, the lane change operation is implemented using the motor, and then, step S316 is performed,

in step S316, the expected lane change vehicle speed is displayed and the driver is prompted to perform the lane change operation.

2. The hybrid vehicle of claim 1, wherein the lane-change operation further comprises the method of:

when it is determined that the driver intends to make a lane change to the right, step S302 is performed,

in step S302, the presence of a third obstacle vehicle (13) and a fourth obstacle vehicle (14) is detected, step S316 is executed if the third obstacle vehicle (13) and the fourth obstacle vehicle (14) are not detected, step S304 is executed if the third obstacle vehicle (13) and the fourth obstacle vehicle (14) are detected,

in step S304, a third distance D3 between the host vehicle (10) and the third obstacle vehicle (13) and a fourth distance D4 between the host vehicle (10) and the fourth obstacle vehicle (14) are determined, then step 306 is performed,

in step 306, comparing the third distance D3 with the third safe distance S3 and the fourth distance D4 with the fourth safe distance S4, the third safe distance S3 and the fourth safe distance S4 are calculated by the following formula:

S3=(V3-V0)*T+D3+∆S，S4=(V4-V0)*T+D4+∆S

wherein T is the expected time of the master vehicle (10) to spend when changing lanes, and S is a second safety threshold;

if the third distance D3 is greater than the third safe distance S3 and the fourth distance D4 is greater than the fourth safe distance S4, step 308 is performed, otherwise, step 304 is performed,

in step 308, the speed V0 of the host vehicle (10), the third speed V3 of the third obstacle vehicle (13) and the fourth speed V4 of the fourth obstacle vehicle (14) are detected, and then step S310 is executed,

at step S310, a fourth speed V4 of the fourth obstacle vehicle (14) is compared with the road speed limit of the current lane, a warning is issued to the driver if the fourth speed V4 reaches the road speed limit, if the fourth speed V4 is less than the road speed limit, step S312 is executed,

in step S312, an expected lane change vehicle speed and a lane change time are determined according to the third distance D3, the fourth distance D4, the speed V0, the third speed V3, and the fourth speed V4, and then, step S314 is performed,

in step S314, engine state information, motor state information, and battery state information are received, if the expected lane change vehicle speed is greater than a predetermined vehicle speed or the battery charge is less than a predetermined value, the lane change operation is implemented using the engine, if the lane change vehicle speed is less than the predetermined vehicle speed and the battery charge is greater than the predetermined value, the lane change operation is implemented using the motor, and then, step S316 is performed.

3. The hybrid vehicle according to claim 1, characterized in that: the hybrid vehicle further includes a camera module and a radar module provided on a front or right side body of the host vehicle.

4. The hybrid vehicle according to claim 2, characterized in that: the Δ S' is greater than Δ S.

5. The hybrid vehicle according to claims 1-4, characterized in that: the steering control unit includes a steering instruction unit including a steering rod located near a steering wheel, a steering execution unit, and the like.

6. The hybrid vehicle according to claims 1-5, characterized in that: if the lane change vehicle speed is less than the predetermined vehicle speed and the battery charge is greater than half or more of the battery state of charge, a lane change operation is implemented using the electric machine.

Technical Field

The invention belongs to the field of vehicles, and particularly relates to a lane changing anti-collision system for a hybrid vehicle and the hybrid vehicle with the lane changing anti-collision system.

Background

When there are many vehicles traveling on adjacent lanes and the vehicle speed is high, many drivers may not capture the lane change timing or may erroneously determine the lane change timing due to insufficient judgment ability and driving experience, which affects road driving safety.

Disclosure of Invention

The invention aims to provide a hybrid vehicle with a lane-changing anti-collision system.

The method is realized by the following technical means:

the hybrid vehicle includes lane change collision avoidance system, the lane change collision avoidance system includes:

a detection unit that determines a first distance D1 between the host vehicle and a first obstacle vehicle in an adjacent left lane, a second distance D1 between the host vehicle and a second obstacle vehicle in the adjacent left lane, a third distance D3 between the host vehicle and a third obstacle vehicle in an adjacent right lane, and a fourth distance D4 between the host vehicle and a fourth obstacle vehicle in the adjacent right lane, and detects a vehicle speed V0 of the host vehicle, a first vehicle speed V1 of the first obstacle vehicle, a second vehicle speed V2 of the second obstacle vehicle, a third vehicle speed V3 of the third obstacle vehicle, and a fourth vehicle speed V4 of the fourth obstacle vehicle, wherein the first obstacle vehicle is located forward of the second obstacle vehicle, and the third obstacle vehicle is located forward of the fourth obstacle vehicle.

An information processing unit that receives the information of the host vehicle, the first obstacle vehicle, to the fourth obstacle vehicle sent by the detection unit and determines whether to perform a lane change operation according to the information.

And a speed control unit receiving the engine information, the motor information and the battery information transmitted by the detection unit and calculating an expected lane change vehicle speed.

And a warning unit for displaying the lane change related information to the driver.

And a steering control unit receiving a steering intention of the driver and indicating a lane change direction.

The lane-changing anti-collision system executes lane-changing operation by the following method:

in step S300, it is determined whether the driver intends to make a lane change based on a signal instructed by the steering control unit, and when it is determined that the driver intends to perform a steering operation, step S301 is performed.

In step S301, the type of steering instructed by the steering control unit is judged, and if it is determined that the driver intends to change lanes to the left, step S303 is performed.

In step S303, the presence or absence of a first obstacle vehicle and a second obstacle vehicle is detected, and if the first obstacle vehicle and the second obstacle vehicle are not detected, step S316 is executed, and if the first obstacle vehicle and the second obstacle vehicle are detected, step S305 is executed.

In step S305, a first distance D1 between the host vehicle and the first obstacle vehicle and a second distance D2 between the host vehicle and the second obstacle vehicle are determined, and then step 307 is performed.

In step 307, comparing the first distance D1 with the first safe distance S1 and the second distance D2 with the safe distance S2, the first safe distance S1 and the second safe distance S2 are calculated by the following formula:

S1=(V1-V0)*T+D1+∆S’，S2=(V2-V0)*T+D2+∆S’。

wherein T is the expected time of the master vehicle when changing lanes, and S' is the first safety threshold.

If the first distance D1 is greater than the first safe distance S1 and the second distance D2 is greater than the second safe distance S2, step 309 is performed, otherwise, step 305 is performed.

In step 309, the speed V0 of the host vehicle, the first speed V1 of the first obstacle vehicle and the second speed V2 of the second obstacle vehicle are detected, and then step S311 is performed.

In step S311, the second speed V2 of the second obstacle vehicle is compared with the road speed limit of the current lane, and if the second speed V2 reaches the road speed limit, a warning is issued to the driver, and if the second speed V2 is less than the road speed limit, step S313 is executed.

In step S313, an expected lane change vehicle speed and a corresponding lane change time are determined according to the first distance D1, the second distance D2, the speed V0, the first speed V1, and the second speed V2, and then, step S315 is performed.

In step S315, engine state information, motor state information, and battery state information are received, if the expected lane change vehicle speed is greater than the predetermined vehicle speed or the battery charge is less than the predetermined value, the lane change operation is implemented using the engine, if the expected lane change vehicle speed is less than the predetermined vehicle speed, the lane change operation is implemented using the motor, and step S316 is performed.

In step S316, the expected lane change vehicle speed is displayed and the driver is prompted to perform the lane change operation.

The lane change operation further comprises the following method:

when it is determined that the driver intends to make a lane change to the right, step S302 is performed.

In step S302, the presence or absence of a third obstacle vehicle and a fourth obstacle vehicle is detected, and if the third obstacle vehicle and the fourth obstacle vehicle are not detected, step S316 is executed, and if the third obstacle vehicle and the fourth obstacle vehicle are detected, step S304 is executed.

In step S304, a third distance D3 between the host vehicle and the third obstacle vehicle and a fourth distance D4 between the host vehicle and the fourth obstacle vehicle are determined, and then step 306 is performed.

In step 306, comparing the third distance D3 with the third safe distance S3 and the fourth distance D4 with the fourth safe distance S4, the third safe distance S3 and the fourth safe distance S4 are calculated by the following formula:

S3=(V3-V0)*T+D3+∆S，S4=(V4-V0)*T+D4+∆S。

wherein T is the expected time of the master vehicle when changing lanes, and Δ S is the second safety threshold.

If the third distance D3 is greater than the third safe distance S3 and the fourth distance D4 is greater than the fourth safe distance S4, step 308 is performed, otherwise, step 304 is performed.

In step 308, the speed V0 of the host vehicle, the third speed V3 of the third obstacle vehicle and the fourth speed V4 of the fourth obstacle vehicle are detected, and then step S310 is performed.

In step S310, the fourth speed V4 of the fourth obstacle vehicle is compared with the road speed limit of the current lane, and if the fourth speed V4 reaches the road speed limit, a warning is issued to the driver, and if the fourth speed V4 is less than the road speed limit, step S312 is executed.

In step S312, an expected lane change vehicle speed and a lane change time are determined according to the third distance D3, the fourth distance D4, the speed V0, the third speed V3, and the fourth speed V4, and then, step S314 is performed.

In step S314, engine state information, motor state information, and battery state information are received, if the expected lane change vehicle speed is greater than a predetermined vehicle speed or the battery charge is less than a predetermined value, the lane change operation is implemented using the engine, and if the lane change vehicle speed is less than the predetermined vehicle speed, the lane change operation is implemented using the motor, and then, step S316 is performed.

The invention has the following effects:

the method comprises the following steps that 1, the speed of each barrier vehicle and the distance between a host vehicle and each barrier vehicle are calculated in real time through a camera module/radar module, different safe distances are set between the host vehicle and each barrier vehicle, the collision between the host vehicle and other vehicles during lane changing can be avoided more accurately, and the safety is improved.

2, when the main vehicle changes lanes, considering that the road speed limit of the left lane is usually higher than that of the right lane, by distinguishing the left lane change and the right lane change, the safety threshold value can be increased when the left lane change overtaking vehicle runs, and the lane change safety is improved.

3, at high vehicle speeds, the engine is generally in a high efficiency region and responds faster to high speeds, so lane changing time can be shortened by operating the engine to perform a lane changing operation. Further, at a low speed of the vehicle, the motor is usually in a high efficiency region and responds quickly to the low speed, and therefore, the lane change time can be shortened by operating the motor to perform the lane change operation, improving lane change safety.

Drawings

Fig. 1 shows a schematic diagram of a road change type according to an exemplary embodiment.

Fig. 2 shows a configuration diagram of a lane change collision avoidance system according to an exemplary embodiment.

FIG. 3 shows a flowchart of a control method of a lane change collision avoidance system according to an exemplary embodiment.

Detailed Description

Referring to fig. 1, a schematic diagram of a road change type according to an exemplary embodiment is shown.

In one embodiment, the host vehicle 10 attempts to merge across the lane line 15 into the right lane, for example, where the driver intends to exit a ramp, make a right turn, etc., a situation where the host vehicle 10 desires to merge into the right lane may occur. In another embodiment, the host vehicle 10 attempts to merge into a left-hand vehicle across the lane line 16, such as may occur if the host vehicle 10 desires to merge into a left-hand lane if the driver intends to cut-in, make a left turn, or the like.

Referring to fig. 2, a configuration diagram of a lane change collision avoidance system of a hybrid vehicle according to an exemplary embodiment is shown. The lane change collision avoidance system 20 of a hybrid vehicle according to an exemplary embodiment may include a detection unit 21, an information processing unit 22, a speed control unit 23, a warning unit 24, and a steering control unit 25.

The detection unit 21 is used to determine the relative positional relationship between the host vehicle and other vehicles in the current lane, the relative positional relationship between the host vehicle and other vehicles in the adjacent lane, and other environmental information in the vicinity of the host vehicle. For example, the detection unit 21 may include a camera module/radar module disposed at the front, left side, right side, and/or rear of the vehicle. Further, the detection unit 21 may further include a sensor for detecting vehicle information of the host vehicle, for example, the detection unit 21 may include a speed sensor for detecting a current speed of the host vehicle, an acceleration sensor for detecting an acceleration, an engine speed sensor for detecting an engine state of the host vehicle, a motor speed sensor for detecting an operation condition of a motor of the host vehicle, a battery level sensor for detecting a power condition of a battery of the host vehicle, and the like.

The information processing unit 22 is used to receive host vehicle information, environmental information, and the like transmitted by the detection unit 21 to determine whether to perform a lane change operation.

The speed control unit 23 is configured to receive the vehicle speed information, the engine information, the motor information, and the like transmitted from the detection unit 21 and the lane change information transmitted from the information processing unit 22 to control the traveling speed of the host vehicle. Further, the speed control unit 23 also calculates a speed for maintaining a safe distance, thereby avoiding a collision between the host vehicle and the lane-change vehicle.

The warning unit 24 may include a visual warning, an audible warning (e.g., a speaker), and the like. When the host vehicle is not eligible to make a lane change, the warning unit 24 may provide a notification to the driver. Further, the warning unit 24 may also provide notification to the driver when it is appropriate to perform a lane change operation.

The steering control unit 25 may include a steering instruction unit that may receive a steering intention of the driver and indicate a lane change direction, and a steering execution unit. For example, the steering indicating unit may include a steering rod located near a steering wheel, and a steering signal of the steering indicating unit may be displayed by a steering indicator lamp provided at the rear of the vehicle. The steering execution unit may cause the host vehicle to execute steering and control a steering angle of the host vehicle, and the like.

The execution logic in the information processing unit 22, the speed control unit 23, and the steering control unit 25 will be described in detail hereinafter.

Referring to FIG. 3, a flow chart of a control method of a lane change collision avoidance system according to an exemplary embodiment is shown.

In step S300, the method determines whether the driver intends to make a lane change based on the instruction signal of the steering instruction unit of the steering control unit 25. When the driver inputs a lane change command (e.g., dials the steering lever), the method proceeds to step S301. Otherwise, the method returns to step S300.

In step S301, the method determines the type of steering indicated by the steering indication unit. As described above in fig. 1, the driver may intend to merge to the right side lane to the right or to merge to the left side lane to the left. For example, the method may determine the driver's steering direction intention based on a detected indication of a steering column. When it is determined that the driver intends to make a right lane change, the method proceeds to step S302, and when it is determined that the driver intends to make a left turn, the method proceeds to step S303.

In step S302, the detection unit 21 detects whether there are obstacle vehicles 13 and 14 located on the right lane of the host vehicle 10 using a sensor such as a camera module/radar module provided on the front or right side vehicle body of the host vehicle 10. If no obstacle vehicles 13 and 14 are detected, the method proceeds to step S316. If an obstacle vehicle is detected, the method proceeds to step S304.

In step S304, the method determines the distance of the host vehicle 10 relative to the obstacle vehicles 13 and 14. As an example, the third distance D3 between the host vehicle 10 and the obstacle vehicle 13 and the fourth distance D4 between the host vehicle 10 and the obstacle vehicle 14 may be determined from the detection results of the camera module/radar module or based on the position information of the onboard GPS or the like. Thereafter, the method proceeds to step 306.

In step 306, the method compares the third distance D3 to the safe distance S3 and compares the fourth distance D4 to the safe distance S4. The safe distances S3 and S4 may be preset distances and may be inversely related to the speed of the vehicle for ensuring that the host vehicle can safely perform the lane change operation.

As an example, the safe distances S3 and S4 may be calculated by the following equation:

S3=(V3-V0)*T+D3+∆S，S4=(V4-V0)*T+D4+∆S。

wherein T is the expected time of the master vehicle when changing lanes, and Δ S is the safe threshold.

In addition, the corresponding safe distance under different vehicle speeds can be found through the lookup table. If it is determined that the third distance D3 is greater than the safe distance S3 and the fourth distance D4 is greater than the safe distance S4, the method may proceed to step 308, otherwise, the method returns to step 304.

In step 308, the method proceeds by determining the speed V0 of the host vehicle 10, the third speed V3 of the obstacle vehicle 13, and the fourth speed V4 of the obstacle vehicle 14. As an example, the traveling speed of the host vehicle 10 may be directly acquired from a vehicle controller or an on-vehicle speed sensor, and the real-time speeds of the obstacle vehicles 13 and 14 may be obtained from the shared information of the on-vehicle GPS. Further, the traveling speeds of the obstacle vehicles 13 and 14 may also be calculated in real time from the information of the camera module/radar module, however, the method of obtaining the speeds of the obstacle vehicles 13 and 14 is not limited thereto. After detecting the speed V0 of the host vehicle 10, the third speed V3 of the obstacle vehicle 13, and the fourth speed V4 of the obstacle vehicle 14, the method proceeds to step S310.

At step S310, the method compares the fourth speed V4 of the obstacle vehicle 14 to the road speed limit. If it is determined that the fourth speed V4 reaches substantially the same road speed limit for the current lane (e.g., the fourth speed V4 reaches 90% of the road speed limit for the current lane), the lane change operation is delayed and the driver is alerted to alert information, such as speed information, through the warning unit 24. If it is determined that although the fourth speed V4 is less than the road speed limit by the predetermined value, the method proceeds to step S312.

In step S312, the speed control unit 23 may determine the expected lane change vehicle speed and the corresponding lane change time according to the above detected third distance D3, fourth distance D4, speed V0 of the host vehicle 10, third speed V3 of the obstacle vehicle 13, and fourth speed V4 of the obstacle vehicle 14. The method then proceeds to step S314.

In step S314, the speed control unit 23 receives the engine state information, the motor state information, and the battery state information, and implements the lane change operation using the engine if the expected lane change vehicle speed is greater than a predetermined vehicle speed (e.g., 80 km/h) or the battery charge amount is less than a predetermined value (e.g., 50% battery state of charge (SOC)), and implements the lane change operation using the motor if the lane change vehicle speed is less than the predetermined vehicle speed. The method then proceeds to step S316.

In step S316, the expected lane change vehicle speed is displayed by the warning unit 24 or other display unit, and the driver is prompted to perform the lane change operation. The method then ends.

In step 301, when it is determined that the driver intends to turn left, the method proceeds to step S303.

In step S303, the detection unit 21 detects whether there are obstacle vehicles 11 and 13 located on the right lane of the host vehicle 10 using a sensor such as a camera module/radar module provided on the front or right side vehicle body of the host vehicle 10. If the obstacle vehicles 11 and 12 are not detected, the method proceeds to step S316. If an obstacle vehicle is detected, the method proceeds to step S305.

In step S305, the method determines the distance of the host vehicle 10 relative to the obstacle vehicles 11 and 12. As an example, the first distance D1 between the host vehicle 10 and the obstacle vehicle 11 and the second distance D2 between the host vehicle 10 and the obstacle vehicle 12 may be determined from the detection results of the camera module/radar module or based on the position information of the onboard GPS or the like. Thereafter, the method proceeds to step 307.

In step 307, the method compares the first distance D1 to the safe distance S1 and compares the second distance D2 to the safe distance S2. The safe distances S1 and S2 may be preset distances and may be inversely related to the speed of the vehicle for ensuring that the host vehicle can safely perform the lane change operation.

As an example, the safe distances S1 and S2 may be calculated by the following equation:

S1=(V1-V0)*T+D1+∆S’，S2=(V2-V0)*T+D2+∆S’。

wherein T is the expected time of the master vehicle when changing lanes, Δ S 'is the safety threshold, and Δ S' may be greater than Δ S.

If it is determined that the first distance D1 is greater than the safe distance S1 and the second distance D2 is greater than the safe distance S2, the method may proceed to step 309, otherwise, the method returns to step 305.

In step 309, the method proceeds by determining the speed V0 of the host vehicle 10, the first speed V1 of the obstacle vehicle 11, and the second speed V2 of the obstacle vehicle 12. As an example, the traveling speed of the host vehicle 10 may be directly acquired from a vehicle controller or an on-vehicle speed sensor, and the real-time speeds of the obstacle vehicles 11 and 12 may be obtained from the shared information of the on-vehicle GPS. Further, the traveling speeds of the obstacle vehicles 11 and 12 may also be calculated in real time from the information of the camera module/radar module, however, the method of obtaining the speeds of the obstacle vehicles 11 and 12 is not limited thereto. After detecting the speed V0 of the host vehicle 10, the first speed V1 of the obstacle vehicle 11, and the second speed V2 of the obstacle vehicle 12, the method proceeds to step S311.

In step S311, the method compares the second speed V2 of the obstacle vehicle 12 to the road speed limit. If it is determined that the second speed V2 is substantially the same as the road speed limit of the current lane, the lane change operation is delayed and the driver is alerted to alert information, such as speed information, through the warning unit 24. If it is determined that although the second speed V2 is less than the road speed limit by the predetermined value, the method proceeds to step S313.

In step S313, the speed control unit 23 may determine the expected lane change vehicle speed and the corresponding lane change time from the above-detected first distance D1, second distance D2, speed V0 of the host vehicle 10, first speed V1 of the obstacle vehicle 11, and second speed V2 of the obstacle vehicle 12. The method then proceeds to step S315.

In step S315, the speed control unit 23 receives the engine state information, the motor state information, and the battery state information, and implements a lane change operation using the engine if the expected lane change vehicle speed is greater than a predetermined vehicle speed (e.g., 80 km/h) or the battery charge is less than a predetermined value (50% SOC), and implements a lane change operation using the motor if the lane change vehicle speed is less than the predetermined vehicle speed. The method then proceeds to step S316.

In step S316, the expected lane change vehicle speed is displayed by the warning unit 24 or other display unit, and the driver is prompted to perform the lane change operation. The method then ends.