Variable Valve Timing and Lift Electronic Control (VTEC) is a system developed by Honda to improve the volumetric efficiency of its internal combustion engines. Its operation modifies valve lift and duration at specific engine speeds to optimize performance across the RPM range. In essence, it alters engine valve behavior based on engine load and speed, transitioning from a low-RPM profile optimized for fuel efficiency and smooth operation to a high-RPM profile designed for increased power output. The specific engine speed at which this transition occurs varies by engine model and manufacturer tuning.
The benefit of such a system lies in its ability to provide both fuel efficiency and increased power within a single engine. Historically, achieving both of these characteristics was difficult due to the inherent trade-offs in valve timing. Early engines were designed with fixed valve timing, which could be optimized for either low-end torque or high-end horsepower, but not both simultaneously. VTEC solves this issue by dynamically adjusting valve timing and lift, resulting in a more versatile and efficient engine. The exact parameters are carefully considered by Honda to balance performance and durability within different applications.
