EMISSION CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the exhaust emission control system are as follows:

      Component Quantity Function
      ECM 1 The ECM controls the fuel injection timing, fuel injection volume and Exhaust Gas Recirculation (EGR) gas flow volume to reduce the exhaust gas emissions in accordance with the signals from the air fuel ratio sensor.
      Controls the air fuel ratio sensor heater.
      NOx Storage Reduction (NSR) Catalyst 1 Stores the NOx.
      Diesel Particulate Filter (DPF) Catalyst 1 Captures the Particulate Matter (PM).
      H2S Oxidation Catalyst 1 Reduces the H2S in the exhaust gas.
      Air Fuel Ratio Sensor 2

      Detects the oxygen concentration in the exhaust gas.

      For details, see the 2WW Engine Control section.

    2. The main components of the Exhaust Gas Recirculation (EGR) system are as follows:

      Component Quantity Function
      ECM 1 Based on the signals received from the sensors, the ECM determines the EGR volume in accordance with the engine operating conditions.
      EGR Temperature Sensor 1 Detects the EGR gas temperature.
      Exhaust Manifold Pressure Sensor 1 Detects the exhaust gas pressure in the exhaust manifold.
      EGR Valve Assembly EGR Valve 1 Actuated by the ECM, this valve controls the flow rate of EGR gas.
      EGR Valve Position Sensor 1 Detects the EGR valve position.
      EGR Cooler Assembly EGR Cooler 1 Cools EGR gas.
      EGR Cooler Bypass Switching Valve 1 Actuated by the ECM via the EGR bypass valve switching valve, this valve switches the flow passage of EGR gas in 2 stages.

    3. The main components of the catalyst regeneration control are as follows:

      Component Quantity Function
      ECM 1 Based on the signals received from the sensors, the ECM determines the injection volume, injection timing and diesel throttle valve opening angle.
      Differential Pressure Sensor Assembly 1 Monitors the differential pressure before and after the DPF catalyst to detect whether the DPF catalyst is clogged.
      Exhaust Gas Temperature Sensor 2 Detects the temperature of the exhaust gas.
      Air Fuel Ratio Sensor 2

      Detects the oxygen concentration in the exhaust gas.

      For details, see the 2WW Engine Control section.
      Injector Assembly 4

      Injects the fuel to the cylinder.

      For details, see the 2WW Fuel section.

      Diesel Throttle Body Assembly


      • Diesel Throttle Valve

      • Throttle Control Motor

      		 1

      Actuated by the ECM, the diesel throttle valve controls the flow rate of intake air.

      For details, see the 2WW Engine Control section and 2WW Intake / Exhaust section.

    4. The main components of the blow-by gas ventilation system are as follows:

      Component Quantity Function
      Pressure Control Valve 1

      Maintains a constant vacuum in the cylinder block sub-assembly.

      For details, see the 2WW Engine Mechanical section.
      Oil Separator 1

      Collects oil mist in the blow-by gas, reducing the oil consumption.

      For details, see the 2WW Engine Mechanical section.

  2. SYSTEM CONTROL


    1. The emission control system has following features:

      System Outline
      Air Fuel Ratio Sensor Heater Control The ECM controls the air fuel ratio sensor heater according to the engine condition in order to promote the warm-up of the air fuel ratio sensor.
      Exhaust Gas Recirculation (EGR) Control Based on the signals received from the sensors, the ECM determines the EGR volume via the EGR valve and EGR cooler bypass switching valve in accordance with the engine condition.
      Catalyst Regeneration Control The ECM judges the NSR catalyst condition based on the fuel injection volume, intake air mass, and exhaust gas temperature to control the injector assemblies for NSR catalyst regeneration control.
      The ECM judges the DPF catalyst condition based on signals from the exhaust gas temperature sensor, differential pressure sensor assembly and air fuel ratio sensor to control the throttle control motor and injector assemblies for DPF catalyst regeneration control.
      Blow-by Gas Ventilation System The amount of airflow through the cylinder block sub-assembly (blow-by gas introduction volume) is controlled in accordance with the engine operating conditions.