Honda developed VTEC (Variable Timing and Lift Electronic Control) to improve the volumetric efficiency of a four-stroke internal combustion engine. Ikuo Kajitani, engineer at Honda was the first involved in the development of these four-valve engines. The Honda’s VTEC system uses two camshaft profiles and hydraulically selects between profiles.
Image source: hdabob.com
VTEC system was used by Honda for good fuel economy and smooth operation of vehicle.
Further Reading:
The VTEC Engine ~ world.honda.com
Checkout the video explains how VTEC system works