ENGINE UNIT


  1. CONSTRUCTION


    1. A 4-blade vane type VVT-i controller (camshaft timing exhaust gear assembly) is used on the exhaust side.

    2. When the engine is stopped, a lock pin locks the exhaust camshaft at the most advanced position in order to enhance startability.

    3. A center spool structure that integrates the camshaft timing oil control valve with the camshaft timing exhaust gear assembly is used. With the shorter oil control circuit, the response of the engine and operation when cold is enhanced.

      Figure 1. VVT-i Controller (Camshaft Timing Exhaust Gear Assembly)

      B0022ZSC01
      *1 Camshaft Timing Oil Control Valve *2 Housing
      *3 Vane (Fixed on Exhaust Camshaft) *4 Lock Pin
      *5 Camshaft Timing Gear Cover RR (Sprocket) *6 Exhaust Camshaft

      Figure 2. Lock Pin

      B0023M7C01
      *a At a Stop *b In Operation
      B0082XT Oil Pressure - -

      Figure 3. Camshaft Timing Oil Control Valve

      B00239RC01
      *1 Camshaft Timing Oil Control Valve - -
      *a To Advance Side Vane Chamber *b To Retard Side Vane Chamber
      *c Engine Oil *d Drain

  2. OPERATION


    1. Advance


      1. The cam timing oil control solenoid assembly operates according to the advance signal from the ECM. When the oil control valve reaches the position shown in the following illustration, the advance side vane chamber of the VVT-i controller (camshaft timing exhaust gear assembly) is affected by oil pressure and the vane inside the VVT-i controller (camshaft timing exhaust gear assembly) rotates in the advanced direction. The exhaust camshaft fixed to the vane also rotates to the advanced side.

        B0023LNC01
        *1 Vane *2 ECM
        *3 Cam Timing Oil Control Solenoid Assembly - -
        *a Rotation Direction *b Retard Side Vane Chamber
        *c Advance Side Vane Chamber *d To Advance Side Vane Chamber
        *e From Retard Side Vane Chamber *f Drain

    2. Retard


      1. The cam timing oil control solenoid assembly operates according to the retard signal from the ECM. When the oil control valve reaches the position shown in the following illustration, the retard side vane chamber of the VVT-i controller (camshaft timing exhaust gear assembly) is affected by oil pressure and the vane inside the VVT-i controller (camshaft timing exhaust gear assembly) rotates in the retarded direction. The exhaust camshaft fixed to the vane also rotates to the retarded side.

        B0022V8C01
        *1 Vane *2 ECM
        *3 Cam Timing Oil Control Solenoid Assembly - -
        *a Rotation Direction *b Retard Side Vane Chamber
        *c Advance Side Vane Chamber *d From Advance Side Vane Chamber
        *e To Retard Side Vane Chamber *f Drain

    3. Hold


      1. The ECM calculates the target advanced angle according to driving conditions and performs control. After setting the target timing, timings are maintained by the neutral camshaft timing oil control valve assembly as long as driving conditions do not change. As a result, unnecessary engine oil discharge is suppressed while valve timings are aligned to the desired target position.