The Dual VVT-i Engine Toyota Corolla is a standout feature that takes this compact sedan to new heights in terms of both efficiency and performance. VVT-i, or Variable Valve Timing with Intelligence, allows the engine to adjust the timing of both the intake and exhaust valves, optimizing engine performance based on driving conditions. The "dual" aspect of this system means that it adjusts both intake and exhaust timing independently, providing more precise control.