Here's why:
* Power Stroke: This is the stage where the burning fuel pushes the piston down, creating power.
* Closed Intake Valve: The intake valve is closed to prevent any fresh air-fuel mixture from entering the cylinder while the combustion process is taking place.
* Closed Exhaust Valve: The exhaust valve is also closed to trap the expanding gases within the cylinder, maximizing the pressure on the piston and therefore the power output.
Key Points:
* The intake and exhaust valves are only open during specific stages of the four-cycle process.
* The power stroke is the only stage where both valves are closed.
* This creates a sealed environment within the cylinder, allowing for efficient combustion and power generation.
