To make the smart hybrid solution, Hyundai introduces the first full hybrid system to use conventional 6-speed step ratio automatic transmission and lithium polymer battery. The simple and economical Sonata hybrid structure offers fun-to-drive characteristics with cooperative control of the engine and motor. The capacity of the electric power system for the Sonata hybrid system is relatively small compared to other existing hybrid systems, but provides smooth and delicate drivability in any extreme environmental situation. The engine clutch which is placed between engine and motor is the core component of the Sonata hybrid system. The precise control of the engine clutch enables optimal power distribution for the two power sources. Anti-jerk strategy is more important to the Sonata hybrid system because there is no active damping component such as a torque converter found in conventional automatic transmission. Finally, the Sonata hybrid system achieves best in class fuel economy and ultimate driving performance.