What is the difference between variable valve timing and variable valve lift?

I've heard the terms variable valve timing and variable valve lift used interchangeably, but are they actually the same thing? And if not, what are the key differences?

Variable valve timing (VVT) and variable valve lift (VVL) are two distinct technologies, but they work together to improve engine performance. VVT adjusts the timing of the engine's valves, while VVL adjusts the height of the valves. This allows for more precise control over the air and fuel mixture entering the engine, resulting in improved fuel efficiency and power output.

Think of VVT as the speed and VVL as the amount. VVT controls when the valves open and close, while VVL controls how much they open. This allows the engine to optimize valve timing and lift for different driving conditions, such as low speeds for better fuel efficiency and high speeds for more power.

It's important to note that while VVL is a newer and more advanced technology, not all engines have it. It's usually found in high-performance or luxury cars, while VVT is more common in everyday vehicles. However, both technologies play important roles in improving engine efficiency and performance.