Patent ID: 8776768

Claim:
An exhaust gas recirculation system for an internal combustion engine having multiple cylinders comprising: a recirculation pipe unit having a gas inlet port connected to an exhaust gas passage of the engine, the recirculation pipe unit further having multiple branched-off pipe portions, each one end of the branched-off pipe portions being communicated to the gas inlet port and each other end of the branched-off pipe portions being respectively connected to each injection port opening to each of intake ports of the engine, so that exhaust gas injected into the respective intake ports flows into respective combustion chambers and flows along an inner wall of the corresponding combustion chamber so as to form swirl flow therein; and multiple EGR control devices respectively provided in each of the branched-off pipe portions, wherein each of the EGR control devices opens each of the corresponding branched-off pipe portions during an exhaust gas recirculation period which is a part of a valve-opening period of a corresponding intake valve, so that the exhaust gas is re-circulated from the exhaust gas passage into the respective combustion chambers for which the corresponding intake valve is opened, and each of the EGR control devices closes the corresponding branched-off pipe portions at least during a valve-closing period of the corresponding intake valve in each combustion cycle in which the exhaust gas is re-circulated.