# US 10,308,248 B2 · Control apparatus and method for improving fuel efficiency in CACC system

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- Number: US 10,308,248 B2
- Document ID: US10308248B2
- Status: Granted
- Kind: B2
- Application number: 15/638,093
- Filed: 2017-06-29
- Published: 2018-01-04
- Granted: 2019-06-04
- Earliest claimed: 2016-07-01
- Assignees: Hyundai Motor Company; Kia Motors Corporation
- Applicants: Hyundai Motor Company; Kia Motors Corporation
- Inventors: Yoon Soo Kim; Dong Gyu Noh; In Yong Jung; Su Lyun Sung; Seung Wook Park; Jong Rok Park; Kyung Joo Bang; Cho Rong Ryu; Min Byeong Lee; Hahk Rel Noh; Dae Sung Hwang
- Web page: https://patentgrep.com/patent/US10308248B2

## CPC

- B60W 30/143: {Speed control (B60W30/16 takes precedence)}
- B60W 30/095: Predicting travel path or likelihood of collision
- B60W 30/0953: {the prediction being responsive to vehicle dynamic parameters}
- B60W 30/16: Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
- B60W 40/04: Traffic conditions
- B60W 2554/80: Spatial relation or speed relative to objects
- B60W 2554/802: Longitudinal distance
- B60W 2556/65: Data transmitted between vehicles
- B60W 2720/103: Speed profile
- B60W 2754/10: Spatial relation or speed relative to objects
- B60W 2754/30: Longitudinal distance
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT

## Abstract

Disclosed herein is a control apparatus and method for improving fuel efficiency in a CACC system, which can improve fuel efficiency through control of a vehicle speed so that a vehicle travels using an optimized cost in consideration of a target vehicle speed, current vehicle speed, minimum driving speed set in the vehicle, and a deceleration distance if the vehicle that uses the CACC system senses a forward vehicle and enters into a CACC active mode. The control method for improving fuel efficiency in a CACC system includes setting a target speed profile based on a target speed of the subject vehicle and an expected driving path, determining whether a target vehicle to be followed by the subject vehicle exists, and controlling the driving speed of the subject vehicle according to the set target speed profile depending on whether or not the target vehicle exists.

## Claims

### Claim 1

A cooperative adaptive cruise control (CACC) system of a subject vehicle to control a driving speed of the subject vehicle, the CACC system comprising:
a communication unit configured to receive vehicle information including position and driving information from neighboring vehicles using Vehicle to Vehicle (V2V) communications;
an information collection unit configured to collect driving information of a forward vehicle and vehicle information of the subject vehicle using sensors of the subject vehicle; and
a controller configured to select a target vehicle to be followed by the subject vehicle based on the vehicle information of the neighboring vehicles that is acquired by the communication unit and the driving information of the forward vehicle that is collected by the information collection unit, to control the driving speed of the subject vehicle based on a target speed of the subject vehicle if the target vehicle to be followed by the subject vehicle is not selected, and to control the driving speed of the subject vehicle based on speed information of the target vehicle, speed information of the subject vehicle, and a target time gap if the target vehicle to be followed by the subject vehicle is selected.

### Claim 2 (depends on 1)

The CACC system according to claim 1,
wherein the controller controls the driving speed of the subject vehicle.

### Claim 3 (depends on 1)

The CACC system according to claim 1, further comprising a driver vehicle interface (DVI) unit configured to receive an input of the target speed or the target time gap or both from a driver and to notify the driver of state information of the CACC system.

### Claim 4 (depends on 1)

The CACC system according to claim 1, wherein the controller is further configured to:
manage a state of the CACC system;
select the target vehicle to be followed by the subject vehicle based on the vehicle information of the neighboring vehicles that is acquired from the communication unit and the driving information of the forward vehicle that is collected by the information collection unit;
set a target speed profile based on the target speed of the subject vehicle and an expected driving path if there is not the target vehicle, and to set a target speed profile based on the speed information of the target vehicle, the speed information of the subject vehicle, and the expected driving path if there is the target vehicle; and
control the driving speed of the subject vehicle according to the set target speed profile.

### Claim 5 (depends on 4)

The CACC system according to claim 4, wherein the controller manages the state of the CACC system as one of an off state in which the CACC system does not operate, a standby state in which the CACC system operates, but does not control the driving speed of the subject vehicle, an ACC activation state in which the driving speed of the subject vehicle is controlled using only the information that is acquired from the subject vehicle in a state where there is no vehicle in a region of interest that is connected through V2V communications, and a cooperative activation state in which there is the neighboring vehicle in the region of interest that is connected through the V2V communications, and the driving speed of the subject vehicle is controlled using the information from the neighboring vehicle that is acquired through the V2V communications and the information that is acquired from the subject vehicle.

### Claim 6 (depends on 4)

The CACC system according to claim 4, wherein the controller sets a new target speed profile if there is a possibility of collision when the driving speed of the subject vehicle is controlled according to the set target speed profile, and resets the target speed profile based on the speed information of the target vehicle, the speed information of the subject vehicle, and the expected path information.

### Claim 7

A control method for improving fuel efficiency in a cooperative adaptive cruise control (CACC) system that is provided in a subject vehicle to control a driving speed of the subject vehicle, comprising:
determining whether to start the CACC system operation;
setting a target speed profile based on a target speed of the subject vehicle and an expected driving path upon starting of the CACC system operation;
determining whether a target vehicle to be followed by the subject vehicle exists;
controlling the driving speed of the subject vehicle according to the set target speed profile if the target vehicle does not exist as the result of the determination;
comparing a minimum distance Ds that can prevent collision with the target vehicle even if the subject vehicle is driven according to the target speed profile with a current distance Dc to the target vehicle if the target vehicle exists as the result of the determination; and
controlling the driving speed of the subject vehicle according to the target speed profile if the current distance Dc is larger than the minimum distance Ds, and performing a fuel efficiency driving if the current distance Dc is smaller than the minimum distance Ds as the result of the comparison,
wherein the fuel efficiency driving is performed in consideration of a driving cost Cc in the case of driving to maintain a decelerated current speed after deceleration so that the minimum distance Ds becomes smaller than the current distance Dc, a driving cost Ccontrol in the case of driving according to a new target speed profile that is generated based on the decelerated current speed, a speed of the target vehicle, the speed of the subject vehicle, a minimum driving speed set in the subject vehicle, a distance required to reach the speed Vtarget of the target vehicle through an auxiliary decelerator, and a distance margin according to a deceleration method.

### Claim 8 (depends on 7)

The control method according to claim 7, wherein the performing the fuel efficiency driving comprises:
comparing the driving cost Cc in the case of current constant-speed driving after the deceleration of the subject vehicle so that the minimum distance Ds becomes smaller than the current distance Dc, with the driving cost Ccontrol in the case of the driving according to the new target speed profile that is generated based on the decelerated current speed;
maintaining the constant-speed driving at the current speed of the subject vehicle or performing the deceleration through comparison of the current speed of the subject vehicle with the speed of the target vehicle if the driving cost Cc is smaller than the driving cost Ccontrol as the result of the comparison; and
comparing the current speed of the subject vehicle with the minimum speed that is set in the subject vehicle if the driving cost Cc is larger than the driving cost Ccontrol as the result of the comparison,
wherein the comparing the current speed of the subject vehicle with the minimum speed that is set in the subject vehicle includes performing decelerated driving through the auxiliary decelerator if the current speed of the subject vehicle is higher than the minimum speed that is set in the subject vehicle, and performing the driving at the minimum speed that is set in the subject vehicle if the current speed of the subject vehicle is lower than the minimum speed that is set in the subject vehicle.

### Claim 9 (depends on 8)

The control method according to claim 8, wherein the maintaining the constant-speed driving at the current speed of the subject vehicle or performing the deceleration through comparison of the current speed of the subject vehicle with the speed of the target vehicle further comprises:
performing the driving at the current speed of the subject vehicle if the current speed of the subject vehicle is lower than the speed of the target vehicle; and
comparing a current distance Dc2 between the subject vehicle and the target vehicle with a sum of a distance Dcruise that is required to reach the driving speed of the target vehicle through the auxiliary decelerator and the distance margin M1 according to the auxiliary decelerator if the current speed of the subject vehicle is larger than the speed of the target vehicle.

### Claim 10 (depends on 9)

The control method according to claim 9, wherein the comparing the current distance Dc2 with the sum of the distance Dcruise and the distance margin M1 comprises:
performing the driving at the current speed of the vehicle if the current distance Dc2 is larger than the sum of the distance Dcruise and the distance margin M1; and
comparing the current distance Dc2 with a sum of a distance Dbrake that is required to reach the driving speed of the target vehicle through performing braking by a brake and a distance margin M2 that is required during the braking by the brake if the current distance Dc2 is smaller than the sum of the distance Dcruise and the distance margin M1.

### Claim 11 (depends on 10)

The control method according to claim 10, wherein the comparing the current distance Dc2 with the sum of the distance Dbrake and the distance margin M2 comprises performing the deceleration through the auxiliary decelerator of the vehicle if the current distance Dc2 is larger than the sum of the distance Dbrake and the distance margin M2, and performing the deceleration through the braking by the brake if the current distance Dc2 is smaller than the sum of the distance Dbrake and the distance margin M2.

### Claim 12 (depends on 7)

The control method according to claim 7, wherein the target speed profile is set in consideration of road information on a driving path of the vehicle.

### Claim 13 (depends on 12)

The control method according to claim 12, wherein the road information comprises a road curvature, a grade, and a radius of rotation.