When the piston reaches TDC, the intake valve is opened and the solenoid is activated to keep it open; when current to the solenoid coil is switched off, the intake valve closes (cutoff).
When the piston reaches TDC, the intake valve is forced opened and the control circuit activates the solenoid to keep the valve open. When control circuit switches off the current to the solenoid coil, the intake valve closes (steam cutoff).