The Variable Valve Timing (VVT) that most of us see in our shops is actually variable “camshaft” timing.

This ­improves low- and high-speed torque by advancing or retarding the camshaft timing on single overhead camshaft (SOHC) engine applications.

In contrast, some double-overhead camshaft (DOHC) applications perform those same functions by separately advancing or retarding the intake and exhaust camshafts.

Variable Valve Timing (VVT)
Variable Valve Timing (VVT)

How does Variable Valve Timing (VVT) work?

  • Your car engine needs to breathe. In addition, Engine valves control the intake of fresh air and the fuel mixture and the exhaust of combustion gases.  VVT adjusts the engine’s timing and breathing based on the operating conditions of the engine. Conventional valve control systems provide a single fixed timing duration. So, This means engine breathing is not adjusted or optimized for the differing requirements.
  • Good timing between the intake and exhaust valves is crucial for optimal engine efficiency. If this timing can be controlled and changed in real-time, based on engine operating parameters, the engine could perform better. As a result, The engine would need less fuel to provide the same amount of power.
  • In addition, VVT helps to optimize combustion, which provides several benefits, including improved engine operation, increased engine power (which allows the use of a smaller engine to achieve the same performance), reduced fuel consumption and decreased emissions.
  • Manufacturers have adopted various VVT design approaches and technologies to control the timing and how long the intake and exhaust valves remain open. The simpler approaches provide just two timing modes (e.g. a camshaft that has lobes of different heights used for lower and higher engine speeds). More sophisticated approaches provide continuously variable timing (e.g. a camshaft that dynamically adjusts its position and timing)

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Each automotive manufacturer has their own unique VVT system.