ENGINE UNIT


  1. CONSTRUCTION


    1. The camshaft timing gear assembly consists of an outer housing that is driven by the timing chain sprocket, and a vane sub-assembly that is coupled to the camshaft.

    2. The camshaft timing gear assembly uses a vane with 4 lobes.

    3. When the engine stops, the camshaft timing gear assembly is locked at the most retarded angle by its lock pin. This ensures excellent engine startability.

    4. The oil pressure sent from the advance or retard side passages of the camshaft (intake) causes rotation of the vane sub-assembly relative to the timing chain sprocket, varying the valve timing continuously.

      A01CSFCC01
      *1 Sprocket *2 Housing
      *3 Vane (Fixed on Intake Camshaft) *4 Intake Camshaft
      *5 Lock Pin - -
      *a At a Stop *b In Operation
      *c Retard Side *d Advance Side
      B002GEN Oil Pressure - -

  2. OPERATION


    1. When the camshaft timing oil control valve assembly is 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.

      A01CRWUC03
      *1 Vane *2 Housing
      *3 Sprocket *4 Intake Camshaft
      *5 Camshaft Timing Oil Control Valve Assembly *6 Spool Valve
      *a In *b Drain
      B002GEN Oil Pressure B002GEA Advance Direction

    2. When the camshaft timing oil control valve assembly is 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.

      A01CRT0C03
      *1 Vane *2 Housing
      *3 Sprocket *4 Intake Camshaft
      *5 Camshaft Timing Oil Control Valve Assembly *6 Spool Valve
      *a Drain *b In
      B002GEN Oil Pressure B002GEA Retard Direction

    3. After reaching the target timing, the engine valve timing is maintained by keeping the camshaft timing oil control valve assembly 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 camshaft timing oil control valve assembly.