EMISSION CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the EGR system are as follows:

      Component Function
      ECM Controls the emission control system based on signals from each sensor.
      Electric EGR Control Valve Assembly Actuated by the ECM, this valve controls the flow rate of EGR gas.
      EGR Valve Position Sensor (Built into Electric EGR Control Valve Assembly) Detects the EGR valve position.
      Diesel Throttle Valve Actuated by the ECM, this valve controls the flow rate of intake air.
      No. 1 EGR Cooler* Cools EGR gas.
      No. 2 EGR Valve Assembly* Switches the flow passage of EGR gas in 2 stages.

      *: Models with EGR cooler

    2. The main components of the catalyst support control are as follows:*

      Component Function
      ECM Controls the emission control system based on signals from each sensor.
      Differential Pressure Sensor

      • Monitors the differential pressure before and after the DPF.

      • Compares this data with the PM accumulation amount calculated by the ECM. If there is a large deviation in the comparison result, the ECM corrects the PM accumulation amount.
      Exhaust Fuel Addition Injector Assembly Injects fuel into the exhaust manifold.
      Exhaust Gas Temperature Sensor Detects the exhaust gas temperature.
      No. 2 Exhaust Gas Temperature Sensor
      No. 3 Exhaust Gas Temperature Sensor
      Air Fuel Ratio Sensor Detects the oxygen concentration in exhaust gas.

      *: Models with catalyst support control

    3. The main components of the UREA SCR system are as follows:*

      Component Function
      ECM Receives the signals from No. 4 Exhaust gas temperature sensor and NOx sensor (nitrogen oxides sensor) and sends the signals to UREA pump control ECU.
      UREA Pump Control ECU Controls the UREA SCR system based on signals from each sensor.
      No. 4 Exhaust Gas Temperature Sensor Detects the exhaust gas temperature.
      NOx Sensor (Nitrogen Oxides Sensor) Detects the concentration of NOx in the exhaust gas.

      *: Models with UREA SCR system

  2. FUNCTION


    1. The main function of the emission control system is as follow:

      Function Outline
      EGR Control This system is designed to help reduce and control NOx formation due to a reduction of peak temperature in the engine combustion chamber, which is accomplished by the introduction of an amount of inert gas into the intake manifold.
      Catalyst Support Control*1

      • When an extremely large amount of PM is accumulated in the DPF, the back pressure of the engine increases and the PM is combusted at once, potentially damaging the filter. In order to prevent that, it is necessary to forcibly combust the accumulated PM. Therefore, the accumulated PM is combusted by increasing the temperature of the filter.

      • If the temperature of the DPF does not increase and the PM keeps accumulating in the DPF, a message is displayed on the multi-information display*3 or the DPF warning light*4 illuminates or blinks to notify the driver.
      UREA SCR System*2 Urea solution is injected by the urea injector set to purify NOx in the exhaust gas.

      *1: Models with catalyst support control

      *2: Models with UREA SCR system

      *3: Models with multi-information display

      *4: Models without multi-information display