SFI SYSTEM


  1. FUNCTION


    1. The Dual Variable Valve Timing-intelligent (VVT-i) system is designed to control the intake and exhaust camshafts within a range of 40° and 35° respectively (of crankshaft angle) to provide valve timing that is optimally suited to the engine operating conditions. This improves torque in all the speed ranges as well as increasing fuel economy, and reducing exhaust emissions.

      A0120JBC01
      *1 Cam Timing Oil Control Valve Assembly (Bank 1 Exhaust Side) *2 Cam Timing Oil Control Valve Assembly (Bank 1 Intake Side)
      *3 VVT Sensor (Bank 1 Exhaust Side) *4 Engine Coolant Temperature Sensor
      *5 Cam Timing Oil Control Valve Assembly (Bank 2 Intake Side) *6 VVT Sensor (Bank 2 Exhaust Side)
      *7 Cam Timing Oil Control Valve Assembly (Bank 2 Exhaust Side) *8 VVT Sensor (Bank 2 Intake Side)
      *9 Crankshaft Position Sensor *10 VVT Sensor (Bank 1 Intake Side)
      *11 ECM *12

      Mass Air Flow Meter Sub-assembly


      • Intake Air Temperature Sensor
      *13

      Throttle Body with Motor Assembly


      • Throttle Position Sensor

      		 - -

    2. The dual VVT-i system delivers excellent benefits in the different operating conditions as shown in the table below.


      1. During Idling

        A0120HHE01
        *1 Earliest Timing (EX)
        *2 TDC
        *3 Latest Timing (IN)
        *4 BDC
        Objective Effect
        Eliminating overlap reduces blow back to the intake side.

        • Stabilized idling engine speed

        • Better fuel economy

      2. At Light Load

        A0120M8E01
        *1 TDC
        *2 To Advance Side (EX)
        *3 To Retard Side (IN)
        *4 BDC
        Objective Effect
        Eliminating overlap reduces blow back to the intake side. Engine stability is ensured

      3. At Medium Load

        A0120DBE01
        *1 To Advance Side (IN)
        *2 TDC
        *3 To Retard Side (EX)
        *4 BDC
        Objective Effect
        Increasing overlap increases internal EGR to reduce pumping losses.

        • Better fuel economy

        • Improved emission control

      4. In Low to Medium Speed Range with Heavy Load

        A0120A7E01
        *1 TDC
        *2 To Retard Side (EX)
        *3 To Advance Side (IN)
        *4 BDC
        Objective Effect
        Advancing the intake valve closing timing improves volumetric efficiency. Improved torque in low to medium speed range

      5. In High Speed Range with Heavy Load

        A0120EME01
        *1 TDC
        *2 To Retard Side (IN)
        *3 To Advance Side (EX)
        *4 BDC
        Objective Effect
        Retarding the intake valve closing timing improves volumetric efficiency. Improved output

      6. At Low Temperatures

        A0120HHE03
        *1 Earliest Timing (EX)
        *2 TDC
        *3 Latest Timing (IN)
        *4 BDC
        Objective Effect
        Eliminating overlap reduces blow back to the intake side to stabilize the idle speed during fast idle.

        • Stabilized fast idle engine speed

        • Better fuel economy

      7. Starting the Engine/Stopping the Engine

        A0120HHE03
        *1 Earliest Timing (EX)
        *2 TDC
        *3 Latest Timing (IN)
        *4 BDC
        Objective Effect
        Eliminating overlap reduces blow back to the intake side. Improved startability