SFI SYSTEM


  1. FUNCTION


    1. For the turbocharger control, wastegate valve control which controls the turbo pressure and air bypass valve control which prevents the surge phenomenon* are used.

      Tech Tips

      *: Surge phenomenon: This phenomenon is when the intake airflow reverses. As a result, an abnormal noise is generated during deceleration.


      1. The ECM cooperatively controls the throttle valve, VVT-iW, VVT-i and wastegate valve to achieve a driving condition with optimal fuel efficiency during normal driving. Also, the ECM controls each actuator in accordance with the driver's intentions during acceleration to achieve a high torque response.

    2. Wastegate Valve Control


      1. During Engine Start


        • The ECM controls the vacuum regulating valve assembly to block the vacuum from the vacuum pump assembly to the actuator and open the wastegate valve. As a result, high temperature exhaust gases are supplied for the catalyst and warm-up time is been reduced.

      2. During Light Loads


        • The ECM controls the vacuum regulating valve assembly to block the vacuum from the vacuum pump assembly to the actuator, opening the wastegate valve and decreasing the exhaust manifold pressure. As a result, fuel economy has been enhanced due to reduced pumping loss and improved combustion (reduction of remaining gas).

      3. During Acceleration and High Loads


        • The ECM controls the vacuum regulating valve assembly to control the vacuum from the vacuum pump assembly to the actuator and close the wastegate valve. As a result, an increase in engine torque and response during acceleration have been achieved.

        A01MQVWE02

        Tech Tips


        • During racing, the wastegate valve is open and the opening and closing operation does not operate.

        • When starting the engine, sound is generated near the wastegate valve that is used to quickly warm up the catalyst, but this is not a malfunction of the turbocharger. When engine warm-up is complete, sound is no longer generated.

    3. Air Bypass Valve Control


      1. The ECM opens and closes the air bypass valve in accordance with driving conditions to prevent the surge phenomenon.

        A01MQS9E02

        Tech Tips


        • During racing, the air bypass valve is closed and the opening and closing operation does not operate.