ENGINE UNIT


  1. CONSTRUCTION


    1. VVT-i controllers consist of the housing driven from the timing chain and the vane coupled with the intake camshaft.

    2. The oil pressure sent from the advance or retard side path at the intake camshaft causes rotation in the VVT-i controller vane circumferential direction to vary the intake valve timing continuously.

    3. When the engine is stopped, the intake camshaft will be in the most retarded state to ensure startability.

    4. When hydraulic pressure is not applied to the VVT-i controller immediately after the engine has started, the lock pin locks the movement of the VVT-i controller to prevent a knocking noise. Thereafter, when hydraulic pressure is applied to the VVT-i controller, the lock pin is released.

      A01KWT5C01
      *1 Timing Rotor *2 Outer Housing
      *3 Vane *4 Lock Pin
      *5 Timing Chain Sprocket *6 Intake Camshaft
      *a Engine Operating *b Engine Stopped
      *c Coupled to Intake Camshaft - -
      B005L08 Oil Pressure - -

  2. OPERATION


    1. Advance


      1. When the cam timing oil control valves are positioned as illustrated below by the advance signals from the ECM, the resultant oil pressure is applied to the timing advance side vane chamber to rotate the camshaft in the timing advance direction:

        A01KX03C01
        *1 Vane *2 Cam Timing Oil Control Valve Assembly
        *3 ECM - -
        *a Advance Side Vane Chamber *b In
        *c Drain - -
        B005L08 Oil Pressure B005L0G Rotation Direction

    2. Retard


      1. When the cam timing oil control valves are positioned as illustrated below by the retard signals from the ECM, the resultant oil pressure is applied to the timing retard side vane chamber to rotate the camshaft in the timing retard direction:

        A01KX6QC01
        *1 Vane *2 Cam Timing Oil Control Valve Assembly
        *3 ECM - -
        *a Advance Side Vane Chamber *b Drain
        *c In - -
        B005L08 Oil Pressure B005L0G Rotation Direction

    3. Hold


      1. After reaching the target timing, the engine valve timing is maintained by keeping the cam timing oil control valve in the neutral position unless the engine operating conditions change. This maintains the engine valve timing at the desired target position by preventing the engine oil from running out of the oil control valve.