Wikipedia
MIVEC (Mitsubishi Innovative Valve timing Electronic Control system) is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors. MIVEC, as with other similar systems, varies the timing of the intake and exhaust camshafts which increases the power and torque output over a broad engine speed range while also being able to help spool a turbocharger more quickly.
MIVEC was first introduced in 1992 in their 4G92 powerplant, a 1,597 cc naturally aspirated DOHC 16 valve straight-4. At the time, the first generation of the system was named Mitsubishi Innovative Valve timing and lift Electronic Control. The first cars to use this were the Mitsubishi Mirage hatchback and the Mitsubishi Lancer sedan. While the conventional 4G92 engine provided at 7000 rpm, the MIVEC-equipped engine could achieve at 7500 rpm. Similar improvements were seen when the technology was applied to the 1994 Mitsubishi FTO, whose top-spec GPX variant had a 6A12 1997 cc DOHC 24 valve V6 with peak power of at 7500 rpm. The GR model, whose otherwise identical powerplant was not MIVEC-equipped, produced at 7000 rpm by comparison.
Although initially designed to enhance performance, the system has subsequently been developed to improve economy and emissions, and has been introduced across Mitsubishi's range of vehicles, from the i kei car to the high-performance Lancer Evolution sedan to the Mirage/Space Star global economy car.
Newest developments have led to MIVEC system being evolved into a continuous variable valve timing and also being the first VVT system to be used into a passenger car diesel engine.