Patent ID: 8646270

Claim:
An engine comprising: an exhaust passage; an intake passage; a controller comprising: a central unit, and a storage unit; and a plurality of superchargers, each of the superchargers comprising: a turbine rotatively driven by receiving exhaust gas flowing in the exhaust passage; and a compressor rotatively driven by the turbine and pressurizing intake air flowing in the intake passage, wherein the turbines of the plurality of superchargers are arranged in the exhaust passage in series, wherein the compressors of the plurality of superchargers are arranged in the intake passage in series, wherein at least one of the superchargers comprises: a supercharger rotation sensor configured to transmit a detection signal obtained from rotation of the corresponding compressor to the controller; a bypass passage for bypassing the exhaust gas from the corresponding turbine; and a bypass valve limiting the flow rate of the exhaust gas flowing in the bypass passage, wherein the controller is configured to execute programming stored in the storage unit to prepare a control signal based on the detection signal from the supercharger rotation sensor and transmit the control signal to the bypass valve so as to limit the rotational speed of each of the compressors so the absolute value of the remainder between an actual supercharger rotational speed of each of the superchargers and a target supercharger rotational speed of each of the superchargers is less than a predetermined value.