Control method for improving fuel efficiency in adaptive cruise control system when preceding vehicle exists

A control method for improving fuel efficiency in an adaptive cruise control system when a preceding vehicle exists, the method comprising steps of:

• setting, by a controller, a target velocity profile based on a current velocity and a current position of a following vehicle when the following vehicle is driven by the adaptive cruise control system;
• determining, by the controller, whether the preceding vehicle exists while driving the following vehicle under the target velocity profile;
• comparing, by the controller, a minimum distance for preventing a collision between the preceding vehicle and the following vehicle in a case of applying the target velocity profile with a first distance which is a distance between the preceding vehicle and the following vehicle when the preceding vehicle exists;
• and
• performing, by the controller, fuel efficiency driving of the following vehicle when the minimum distance is larger than the first distance and performing driving of the following vehicle according to the target velocity profile when the minimum distance is smaller than the first distance,
• wherein the fuel efficiency driving is set by considering a first driving cost for maintaining the current velocity of the following vehicle, a second driving cost in a case of applying a new target velocity profile when the minimum distance is secured after deceleration, a velocity of the preceding vehicle, the current velocity of the following vehicle, a lowest driving velocity set in the following vehicle, a distance required to reach a current velocity of the preceding vehicle while maintaining the fuel efficiency driving, and a deceleration distance.