When will the intake valve of South Sudan open?

Ignition sequence is 1, 3, 4, 2. That is to say, when 1 cylinder does work, cylinder 3 is in compression state, cylinder 4 is in intake state, and cylinder 2 is in exhaust state. According to the ignition sequence 1, 3, 4, 2, the difference between intake valve and exhaust valve is as follows:

1 and 1 The intake valve and exhaust valve of the cylinder are closed (work is done and the piston is at the top dead center position).

The exhaust valve of cylinders 2 and 3 is closed, and the intake valve is just closed (compression starts, and the piston is at the bottom dead center position).

The exhaust valves of cylinders 3 and 4 have just closed and the intake valves have just opened (the beginning of intake can be understood as the end of exhaust, the beginning of intake, and the piston at the top dead center position).

The exhaust valves of cylinders 4 and 2 have just been opened, and the intake valves are closed (exhaust starts, and the piston is at the bottom dead center position).