Intake/exhaust valve and operation control method for internal combustion engine

An intake/exhaust valve for an internal combustion engine, comprising:

• a housing provided on an intake port and/or an exhaust port, which communicates with a combustion chamber, the housing having a plate-shaped portion provided with a plurality of fixed slits radially extending from a central axis of the port;
• a valve element provided adjacent to the plate-shaped portion, the valve element being rotatable about the central axis and being provided with a plurality of movable slits radially extending from the central axis;
• and
• a drive mechanism rotating the valve element about the central axis to change a relative positional relationship between the fixed slits and the movable slits;
• wherein the drive mechanism comprises an annular member, provided in the housing to be rotatable about the central axis and has permanent magnets arranged evenly distributed around the central axis, and electromagnets, provided outside the housing and disposed at positions corresponding to the permanent magnets,
• the electromagnets are arranged such that first and second ends of iron cores are close to the annular member, the permanent magnets are arranged such that an N-pole or an S-pole is close to the first and second ends of the iron cores, and when the first end faces one of the electromagnets, the second end is offset from the other electromagnet.