INTAKE SYSTEM


  1. CONSTRUCTION


    1. A variable nozzle vane type turbocharger is used. A water jacket is provided in the bearing housing to improve the cooling performance of the turbocharger.

    2. This turbocharger has achieved great improvements in low-speed torque, maximum output, fuel consumption, and emission reduction. These improvements have been accomplished through variable control of the nozzle vane position, and an optimal velocity of the exhaust gas inflow to the turbine at all times in response to the engine condition.

    3. The ECM outputs a signal to the turbo motor driver, which actuates the DC motor, to control the nozzle vane position.

    4. The variable nozzle vane type turbocharger consists primarily of a compressor wheel, turbine wheel, nozzle vane, unison ring, drive arm, driven arm, DC motor, linkage and nozzle vane position sensor.

      B002MZ6C01
      *1 DC Motor *2 Nozzle Vane Position Sensor
      *3 Compressor Wheel *4 Turbine Wheel
      *5 Water Jacket *6 Nozzle Vane
      *7 Unison Ring *8 Full-close Stopper
      *9 Linkage *10 Driven Arm
      *11 Drive Arm - -

      Tech Tips


      • To control the nozzle vane position, the turbo motor driver renders the contact position of the linkage with the full-close stopper (thus fully closing the nozzle vane) as the zero point for the nozzle vane position sensor.

      • If the turbocharger has been reinstalled or replaced, turn the ignition switch from ON to off once, and make sure that the linkage comes in contact with the full-close stopper.

      • The full-close stopper position, which is adjusted at the factory at the time of shipment, is not serviceable in the field. For this reason, if the linkage does not come in contact with the full-close stopper during an inspection, the turbocharger sub-assembly must be replaced. Never attempt to loosen or tighten the lock nut of the full-close stopper because it will adversely affect the performance of the engine.

      • For details, refer to the Repair Manual.

        B002NJDC01
        *1 Linkage *2 Full-close Stopper
        *3 Lock Nut - -
        *a Open *b Closed

  2. OPERATION


    1. The exhaust gas from the exhaust manifold goes through the nozzle vane inside the turbo charger housing, and flows to the exhaust pipe through the turbine. The speed of the turbine (supercharging pressure) differs depending on the flow velocity of the exhaust gas going through the turbine and the flow velocity of the exhaust gas is controlled by the opening. In such a time of idling, when the exhaust gas is less, the nozzle vane is almost fully closed, but as there is a slight clearance between the vanes, the exhaust gas flows through this clearance to the exhaust pipe. Therefore, there is no bypass.

      B002NAZC01
      *1 Nozzle Vane - -
      B002N8P Intake Air B002NKU Exhaust Gas

    2. When the engine is running in a low speed range, the DC motor presses down the linkage by a signal from the turbo motor driver. The tip of the linkage rotates the unison ring counterclockwise through a drive arm. The unison ring contains a driven arm, which is placed through the cutout portion of the unison ring. This driven arm also moves in the direction of the rotation of the unison ring. The fulcrum of the driven arm is an axis that is integrated with the nozzle vane behind the plate. When the driven arm moves counterclockwise, the nozzle vane moves toward the closing direction. This results in increasing the velocity of the exhaust gas flowing to the turbine, as well as the speed of the turbine. As a result, torque is improved when the engine is running at low speeds.

      B002NA2C01
      *1 Nozzle Vane *2 Plate
      *3 DC Motor *4 Linkage
      *5 Unison Ring *6 Driven Arm
      *7 Drive Arm *8 Fulcrum
      *9 Cutout Portion of Unison Ring - -
      *a Gas Flow *b Movement of Linkage
      *c Rotation Direction of Unison Ring - -

    3. When the engine is running in a medium-to-high speed range, the DC motor pulls up the linkage by a signal from the turbo motor driver. With this, the driven arm moves clockwise and this opens the nozzle vane and holds the specified supercharging pressure, thus lowering the back pressure and improving the output and fuel consumption.

      B002MUJ