Draw the valve timing diagram of 4 Stroke naturally aspirated and supercharged engine and why overlap period is more in pressure charged engine?

Advantage of large overlap period:

The large overlap period in the pressure charged engine allows complete expulsion of exhaust gases from the cylinder. During this period, a large amount of air passes through the inlet valve, cylinder, exhaust valve and cooling the parts in the process. This cooling helps to keep the surface temperatures of these parts at a lower value, which reduces thermal stresses.

After the exhaust valve closes, less heat is passed into the air that follows into the cylinder and a greater mass of air is therefore present when compression begins.