What does a dual VVT-i engine mean?
2 Answers
VVT is an English abbreviation, which stands for "Variable Valve Timing" in Chinese. It is controlled by an electronic control unit (ECU). The system mainly controls the intake camshaft, and the additional "i" is the code for "Intake" in English. 1. Introduction: VVT-i is a device that controls the valve timing of the intake camshaft. It optimizes the timing by adjusting the camshaft angle, thereby improving the engine's power and fuel economy across all speed ranges while reducing exhaust emissions. 2. Working Principle: When the engine shifts from low speed to high speed, the computer automatically directs oil pressure to the small turbine inside the intake camshaft drive gear. Under pressure, the small turbine rotates a certain angle relative to the gear housing, allowing the camshaft to rotate forward or backward within a 60-degree range. This changes the timing of the intake valve opening, achieving continuous adjustment of the valve timing.
When driving my Toyota Corolla equipped with the dual VVT-i system, I feel the engine response is incredibly sharp. Simply put, dual VVT-i is an intelligent valve timing technology that allows independent variation of both intake and exhaust camshafts. Previously, I drove a car with single VVT-i, which only adjusted the intake side, sometimes causing hesitation or jerking when climbing hills or in city traffic jams. But with the dual system fully operational, power surges instantly when I press the accelerator, resulting in smoother and more linear acceleration. This design significantly reduces fuel consumption; I often drive on highways and have measured savings of nearly 1 liter per 100 kilometers. It also cuts emissions because combustion is more complete. After driving it for over two years, the power remains consistently stable, and my mechanic says its simple and durable structure benefits from regular high-quality oil changes to keep the system running smoothly. Overall, dual VVT-i makes driving smarter and more eco-friendly.
