SFI SYSTEM CONTROL VARIABLE VALVE TIMING CONTROL

  1. FUNCTION

    1. The dual variable valve timing system delivers excellent benefits during different vehicle operation states as shown in the table below.

      Table 1. During Idling

      Objective

      Effect

      Decreasing overlap to reduce blow back to the intake side.

      • Stabilized idle speed

      • Better fuel economy

      Table 2. At Light Load

      Objective

      Effect

      Decreasing overlap to reduce blow back to the intake side.

      Ensured engine stability

      Table 3. At Medium Load

      Objective

      Effect

      Increasing overlap to increase internal EGR to reduce pumping loss.

      • Better fuel economy

      • Improved emission control

      Table 4. In Low to Medium Speed Range with Heavy Load

      Objective

      Effect

      Advancing the intake valve close timing for volumetric efficiency improvement.

      Improved torque in low to medium speed range

      Table 5. In High Speed Range with Heavy Load

      Objective

      Effect

      Retarding the intake valve close timing for volumetric efficiency improvement.

      Improved output

      Table 6. At Low Temperatures

      Objective

      Effect

      Eliminating overlap to reduce blow back to the intake side leads to a lean condition and stabilizes the idle speed at fast idle.

      • Stabilized fast idle speed

      • Better fuel economy

      Table 7. Upon Starting / Stopping the Engine

      Objective

      Effect

      Eliminating overlap to reduce blow back to the intake side.

      Improved startability