Air engine with rotatable intake-exhaust mechanism

An air engine, comprising:

• a cylinder;
• a piston capable of reciprocating in the cylinder;
• a gas supply supplying a compressed gas to move the piston;
• and
• an intake-exhaust mechanism, which is connected to the cylinder and the gas supply and comprises:
• a body having a chamber, and an intake channel, an exhaust channel, an inlet port and an outlet port, which communicate with the chamber, wherein the intake channel and the exhaust channel communicate with the chamber and the cylinder;
• and
• an intake-exhaust assembly, which is rotatable within the chamber, controls the inlet port to be connected to the intake channel or not upon rotation, and controls the outlet port to be connected to the exhaust channel or not upon rotation, so that the compressed gas enters the cylinder via the inlet port and the intake channel to drive the piston, wherein after driving the piston, the compressed gas becomes an exhaust gas, which is exhausted from the cylinder via the exhaust channel and the outlet port.