24/04/2025
What are VVTI and VTEC?💨🛠️🔧👇
An engine operates by burning a fuel-air mixture, which expands and exerts pressure. If more air is introduced, the pressure on the piston increases, resulting in greater power output. This process is known as cylinder charging.
However, in a naturally aspirated (non-turbo) engine, there is a limit to how much cylinder charging can be increased under atmospheric pressure. Various methods have been developed to improve cylinder charging efficiency.
Why does cylinder charging decrease?
In a 4-stroke engine, the fuel-air mixture enters through the intake valve during the intake stroke. The intake valve opens to allow air to enter the cylinder and closes at the end of the stroke. However, since an engine completes a cycle in just milliseconds, the time available for the intake valve to remain open is very short, especially at high RPMs.
When an engine runs at high speeds, there isn't enough time to fully fill the cylinder with air, leading to reduced pressure on the piston during combustion. This, in turn, reduces power and efficiency.
