EMISSION CONTROL SYSTEM CONTROL EMISSION CONTROL

  1. FUNCTION OF MAIN COMPONENTS

    1. The main components of the 1KR-FE emission control system are as follows.

      Component

      Function

      TWC

      Reduces emissions by oxidation of CO and HC in exhaust gas and reduction of NOx.

      Heated Oxygen Sensor

      Detects the oxygen concentration in the exhaust gas by measuring the electromotive force which is generated in the sensor itself.

      EGR Valve Assembly

      Opens and closes based on signals from the ECM and controls the flow rate of the exhaust gas in the EGR bypass.

      Ventilation Valve Sub-assembly

      Controls the flow rate of blowby gas by opening and closing a valve using vacuum generated in the intake manifold.

      Purge VSV

      Controls the flow rate of evaporative emissions by opening and closing a valve based on signals from the ECM.

      ECM

      • Controls the volume of fuel consumed based primarily on the signal from the heated oxygen sensor, with minor corrections based on the signal from the heated oxygen sensor. This control optimizes the air fuel ratio.

      • Regulates the EGR volume in accordance with the various sensor signals.

  2. SYSTEM CONTROL

    1. EGR Control

      1. This system is designed to reduce and control NOx formation due to a slight reduction of the peak temperature in the engine combustion chamber and to improve fuel economy, which is accomplished by introducing a small amount of inert gas into the intake passage.

      2. By sensing the engine driving conditions and actual amount of the EGR valve assembly opening, the ECM operates the EGR valve assembly and throttle control motor, and regulates the amount of exhaust gas.

      3. The EGR valve assembly regulates the flow volume of exhaust gas passing through the cylinder head sub-assembly and returns the gas to the intake manifold.

        W104790E02

    2. Blowby Gas Ventilation System

      1. By introducing blowby gas that has a large amount of HC into the air intake and burning it again, the system attempts to enhance the emission performance. The volume of returned blowby gas is regulated to the appropriate amount corresponding to the engine operating conditions, reducing the volume of engine oil and the impact on the engine idle speed.

      2. The Positive Crankcase Ventilation (PCV) valve passage returns blowby gas into the area after the throttle valve in accordance with the intake manifold vacuum.

      3. When the engine load is low, the passage from the cylinder head cover sub-assembly to the area before the throttle valve increases the air purification performance inside the crankcase by introducing fresh air, and when the engine load is high, the passage circulates the blowby gas together with the ventilation valve sub-assembly side passage due to the intake manifold vacuum.

      4. An oil separator chamber has been provided to reduce oil degradation and consumption.

        W104791C01

        *1

        Air Cleaner Case

        *2

        Intake Manifold

        *3

        Cylinder Head Cover Sub-assembly

        *4

        Ventilation Valve Sub-assembly

        *5

        Oil Separator

        *6

        Crankcase

        *a

        Fresh Air

        *b

        Blowby Gas