It should be i-VTEC and VVT-i; the former is the English abbreviation of variable valve timing and lift electronic control system, which is a system developed by Honda that can control both valve opening and closing time and lift at the same time. The valve control system under different conditions can appropriately adjust the valve timing and valve lift as the engine speed, load, water temperature and other operating parameters change, so that the engine can achieve the highest efficiency at both high and low speeds; the latter It is the English abbreviation of Intelligent Variable Valve Timing System. It is Toyota's patented technology. However, the VVT-i system can continuously adjust the valve timing, but it cannot adjust the valve lift. Hope I can help you~~