How to Fix Variable Valve Timing in Your Car (VTEC)
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Know Your Toyota Mechanical: Variable Valve Timing with Intelligence (VVT-i)
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Toyota VVT (Variable Valve Timing)
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Toyota VVT-iE, Variable Valve Timing
In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with variable valve lift systems. There are many ways in which this can be achieved, ranging from mechanical devices to electro-hydraulic and camless systems. Increasingly strict emissions regulations are causing many automotive manufacturers to use VVT systems.
Background theory
Challenges
History
Automotive nomenclature
Methods for implementing Variable Valve Control (VVC)