Idle Stop and Go (ISG), also known as Automatic Engine Stop/Start, has been widely implemented in production vehicles as one of the “Eco” functions that save fuel, and the application has been promoted to meet stringent fuel economy regulations throughout the world. However, the vibration and the hesitation caused by engine stop and restart often discourage the usage. Because a conventional ISG system usually restarts the engine when it sees the brake pedal release, the driver may perceive a delay in immediate vehicle launch. Furthermore, there are some driving conditions where engine on/off is undesirable or unnecessary. A quick stop-and-go situation such as making a complete stop at a stop sign is one of the conditions where ISG would be inappropriate, and in those cases, ISG may irritate the driver or even end up increasing fuel consumption with too frequent engine stop/start.
In order to mitigate aforementioned issues, a utilization of Advanced Driver Assistance System (ADAS) is proposed. With the surrounding traffic information obtained from the ADAS module, ISG control algorithm is able to determine when to turn on or off the engine prior to driver’s input. The applications demonstrated in this paper include the following usage examples: The ISG control logic monitors the movement of the vehicle in front and restarts the engine out of ISG mode before brake release, which eliminates the delay in the following vehicle launch. By employing traffic sign recognition and vehicle location info, the control logic is also able to inhibit engine off when the vehicle stops at stop signs which will avoid unwanted ISG activation.
In this paper, the advanced ISG control logic is introduced, and the real-world vehicle test results are provided with the description of prototype vehicle configuration.