Hybrid Electric City Bus Control Strategy Based on Driving Cycle

City bus driving cycle plays an important role on control strategy of Hybrid Electric Vehicle. A testing system based on Data Stream function of vehicle electronic control system was developed to test the city bus driving cycle. By measuring such parameters as engine speed, throttle position, vehicle speed and passenger number, statistic results indicated that parking time, vehicle speed, acceleration, deceleration and passenger number accorded with normal school. In all the running time of a city bus, idle speed time account for 25.3 percent, acceleration and deceleration time 69.1 percent, and even speed time account for 5.6 percent According to the driving cycle development, hybrid electric city bus control strategy was optimized. Research result indicates that engine consume less fuel as engine idle speed cycle limited. We use small power engine to improve engine's running state and adopt regenerative brake technique. Optimizing of powertrain control strategy was the key technique of Hybrid Electric Vehicle. Structure and control strategy of Series Hybrid Electric Vehicle and Parallel Hybrid Electric Vehicle were analyzed.