Today we're talking about the variable valve timing system or VVT. How it works, using the VVTC as an example. The video you've all been waiting for! What is VVT or variable valve timing? How does a variable valve timing system regulate the engine's timing?

Every automaker calls a variable valve timing system differently, e.g. cvvt, vvt-i, vvc, vvt, vcp, VANOS, VTEC, VVEL, etc.

Why do you need a variable camshaft timing system in an engine? The camshaft rotates and the intake/exhaust valves open and close. Because of the constant camshaft shape, the valves always open at the same time and have the same stroke relative to the crankshaft. But there is one problem. The way the engine operates at high and low RPMs is different. For example, at high RPMs, the valves must open earlier than at low RPMs. Because it takes time for the combustion chamber to fill with air. That's where the shape of the cams comes from. They are shaped to compensate and equalize the valves. But the best solution is the variable valve timing system.

The variable valve timing system changes the valve opening time, valve stroke and opening duration, depending on the engine operating mode. I.e. the vvt adapts to the work of the engine and adjusts the timing of the car. The variable valve timing system increases torque and engine power and reduces emissions.

Let's talk about the timing system and how does it work? Many variable camshaft phasing systems use camshaft advancement to open the valve faster. Such a system is called a CVVT. How does this work? To do this, there is a hydraulic clutch (phasing unit) on the camshaft, which I'm sure you've heard of. This clutch or phasing unit turns the camshaft when needed. How does it work? See our video next.

A variable camshaft timing system can be installed on a camshaft that is responsible for both the intake and exhaust valves. Such a system is called variable dual valve timing. For example, there is VANOS in BMW, where there may be two phasing units, or there may be one.

The variable valve timing system has its own electronic control unit, which coordinates the operation of the system.
I told you about VVT , based on dovetailing, but there are other systems as well. For example, the Honda VTEC, where the cam timing system is based on different cam shapes. But we will talk about it in other videos.

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