SFI SYSTEM


  1. FUNCTION


    1. The Variable Valve Timing-intelligent (VVT-i) system is designed to control the exhaust camshaft within a range of 55° (of crankshaft angle) to provide valve timing that is optimally suited to the engine operating condition. This improves torque in all the speed ranges as well as increasing fuel economy and reducing exhaust emissions.

      A01MQU2E02

    2. The following effects can be achieved due to the advanced angle and retarded angle of the intake and exhaust valves.

      Figure 1. Operation Model Diagram: Upon Starting and Idling

      A01MQUBE04
      *1 Exhaust Valve Opening (Advanced Position)
      *2 Intake Valve Opening (Intermediate Position)
      *3 Ensuring Starting Ability

      Figure 2. Operation Model Diagram: At Partial Load

      A01MQOHE03
      *1 Exhaust Valve Opening (Retarded Position)
      *2 Intake Valve Opening (Retarded Position)
      *3 Atkinson Cycle

      Figure 3. Operation Model Diagram: At Partial Load to Heavy Load

      A01MQT7E03
      *1 Exhaust Valve Opening (Retarded Position)
      *2 Intake Valve Opening (Advanced Position)
      *3 Using Internal EGR or Improving Exhaust Ability

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