SFI SYSTEM


  1. FUNCTION


    1. The VALVEMATIC effects coordinate control with the Dual VVT-i. It effects continuously variable control of the amount of intake valve lift, intake valve action angle and intake valve timing, as well as control of the exhaust valve timing, in accordance with the engine conditions. This results in improved engine performance and better fuel economy.

    2. The intake valve action angle varies between 106° CA and 260° CA, and the amount of intake valve lift varies between 0.9 mm (0.0354 in.) and 10.9 mm (0.429 in.).

    3. The VALVEMATIC consists of a continuously variable valve lift controller assembly at the actuator and VALVEMATIC mechanism.

    4. Along with the use of this system, a vacuum pump assembly is provided in order to provide the proper brake control vacuum.

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      *1

      Continuously Variable Valve Lift Controller Assembly


      • EDU

      • Motor Position Sensor

      • Action Angle Sensor

      		 *2 Vacuum Pump Assembly
      *3 Various Sensors *4 ECM
      *a VALVEMATIC Mechanism *b CAN (Local Bus)

    5. The continuously variable valve lift controller assembly operates the VALVEMATIC mechanism in accordance with signals from the ECM in order to control the amount of intake valve lift and the intake valve action angle.

    6. The VALVEMATIC effects coordinate control with the Dual VVT-i and ETCS-i.

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    7. The VALVEMATIC controls the amount of intake valve lift, intake valve action angle, intake valve timing and exhaust valve timing in order to achieve the following effects:


      1. Upon Starting and Stopping Engine

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        Amount of Valve Lift/Valve Action Angle Objective Effect

        • Intake valve action angle is fixed at 200° CA.

        • During cranking, if the ECM determines that the engine has started, the intake valve action angle moves to 255° CA.

        		 Eliminating overlap to reduce blow back to the intake side

        • Stabilized idling speed

        • Better fuel economy

      2. At First Idling

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        Amount of Valve Lift/Valve Action Angle Objective Effect
        Intake valve action angle is fixed at 255° CA. Increasing overlap to increase internal EGR Improved emission control

      3. Before Engine Warm-up (Except First Idling)

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        Amount of Valve Lift/Valve Action Angle Objective Effect
        Intake valve action angle is fixed at 240° CA. Improving intake air charging efficiency

        • Improved output

        • Better fuel economy

      4. At Light and Medium Load (After Warm-up)

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        Amount of Valve Lift/Valve Action Angle Objective Effect

        • Effects coordinate control with Dual VVT-i and ETCS-i.

        • Amount of intake valve lift is variable.

        • Intake valve action angle is variable within a range between 106° CA and 245° CA.

        		 Closing the intake valve early to reduce pumping loss Better fuel economy

      5. At Heavy Load (After Warm-up)

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        Amount of Valve Lift/Valve Action Angle Objective Effect

        • Effects coordinate control with Dual VVT-i.

        • Amount of intake valve lift is variable.

        • Intake valve action angle is variable within a range between 230° CA and 260° CA.

        		 Closing the intake valve late, thus retarding the injection timing, to improve volumetric efficiency

        • Improved output

        • Better fuel economy

        • Reduction of exhaust gas temperature