SFI SYSTEM CONTROL VARIABLE VALVE TIMING CONTROL

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