ENGINE UNIT


  1. CONSTRUCTION


    1. A camshaft control actuator (camshaft timing gear assembly) which is operated by the cam timing control motor with EDU assembly is used for the intake side Variable Valve Timing-intelligent by Electric motor (VVT-iE) system.

    2. The 2-stage cycloid reduction unit which reduces the speed of the cam timing control motor with EDU assembly and varies the phase of the intake camshaft is used for the camshaft control actuators (camshaft timing gear assembly).

    3. The ECM rotates the planetary gear using the camshaft control actuators (camshaft timing gear assembly) installed to the timing chain cover assembly on the front end of the camshaft control actuators (camshaft timing gear assembly) via the reduction unit. By rotating the planetary gear, the phase of the intake camshaft which is fixed to the cam sprocket and camshaft gear can be varied.

      B0056A1C01
      *1 Cam Timing Control Motor with EDU Assembly *2 Sprocket Gear
      *3 Bearing *4 Eccentric Shaft
      *5 Planetary Gear *6 Camshaft Gear
      *7 Sprocket *8 Intake Camshaft
      *a Cycloid Reduction Unit - -
      B0056PTC01
      *1 Cam Timing Control Motor with EDU Assembly *2 Sprocket Gear
      *3 Bearing *4 Eccentric Shaft
      *5 Planetary Gear *6 Large Gear
      *7 Small Gear *8 Camshaft Gear
      *9 Sprocket *10 Intake Camshaft
      *a Cycloid Reduction Unit - -

  2. OPERATION


    1. Reduction unit


      1. The reduction unit consists of a sprocket gear, an eccentric shaft, a planetary gear and a camshaft gear.

      2. The eccentric shaft is circular and offset from the axis of the camshaft, and drives the planetary gear.

      3. The sprocket gear has 1 tooth more than the large gear of the planetary gear and the camshaft gear has 1 tooth more than the small gear of the planetary gear.

      4. When the eccentric shaft rotates, the planetary gear is forced to move eccentrically which causes it to rotate as its teeth are engaged with the sprocket gear and camshaft gear.

      5. For every 1 turn of the eccentric shaft by the cam timing control motor with EDU assembly, the planetary gear moves 1 tooth on the sprocket gear and 1 tooth on the camshaft gear.

        B0056QBC01
        *1 Sprocket Gear *2 Eccentric Shaft
        *3 Planetary Gear (Large Gear) *4 Camshaft Gear
        *5 Planetary Gear (Small Gear) - -
        *a Eccentric shaft rotates 120° *b Eccentric shaft rotates 240°
        *c Eccentric shaft rotates 360° *d Rotates by 1 tooth of planetary gear

    2. Operation when advancing or retarding


      1. When advancing


        • By rotating the motor faster than the camshaft speed in accordance with a signal from the ECM, the camshaft gear rotates via the reduction unit in the direction shown in the illustration. As the intake camshaft is directly connected to the camshaft gear, the camshaft timing advances.

          B0056V0C01
          *1 Cam Timing Control Motor with EDU Assembly *2 Sprocket Gear
          *3 Eccentric Shaft *4 Planetary Gear
          *5 Camshaft Gear *6 Sprocket
          *a Sprocket Speed *b Camshaft Speed
          *c Advance Side *d Camshaft Gear Cross Section

      2. When retarding


        • By rotating the motor slower than the camshaft in accordance with a signal from the ECM, the camshaft gear rotates via the reduction unit in the direction shown in the illustration. As the intake camshaft is directly connected to the camshaft gear, the camshaft timing retards.

          Tech Tips

          The motor rotates in the forward or reverse direction depending on the camshaft speed.

          B005643C02
          *1 Cam Timing Control Motor with EDU Assembly *2 Sprocket Gear
          *3 Eccentric Shaft *4 Planetary Gear
          *5 Camshaft Gear *6 Sprocket
          *a Sprocket Speed *b Camshaft Speed
          *c Retard Side *d Camshaft Gear Cross Section

      3. When holding


        • When the target valve timing has been reached, the ECM rotates the motor at the same rotational speed as the camshaft until the target valve timing changes.