Evaporated fuel processing apparatus for internal combustion engine

An evaporated fuel processing apparatus for an internal combustion engine comprising:

• a canister configured to receive evaporated fuel from a fuel tank to be adsorbed temporarily in the canister, and
• a purge passage that supplies a purge gas including the evaporated fuel separated from the canister to an intake system of the internal combustion engine therethrough, and
• a pulsation pump that supplies the purge gas to the intake system by a pumping action responsive to intake pulsation generated in an intake passage of the internal combustion engine,
• the pulsation pump comprising:
• a first chamber,
• a communication passage directly communicating with the first chamber and the intake passage,
• an elastic body forming at least a part of a wall part sealing the first chamber and being deformed depending on pressure fluctuation of the first chamber,
• a second chamber formed so as to surround the elastic body,
• a suction port provided with a suction valve allowing inflow of gas into the second chamber, and
• a discharge port provided with a discharge valve allowing outflow of gas from the second chamber.