EMISSION CONTROL SYSTEM


  1. OUTLINE


    1. 2 Three-Way Catalytic converters (TWCs) are used in the exhaust system in order to reduce exhaust emissions.

    2. The ECM performs air-fuel ratio feedback control based on signals from the air fuel ratio sensor and the oxygen sensor, and controls the fuel injection amount so that the air-fuel ratio comes close to the stoichiometric air-fuel ratio at which the highest purifying efficiency of CO, HC and NOx is obtained.

    3. Air fuel ratio sensor and oxygen sensor heater control, which maintain the temperature of the respective sensors at an appropriate level, are used to improve the detection accuracy of the exhaust gas oxygen concentration.

    4. EGR control, together with the high efficiency EGR cooler, offers high fuel efficiency. In addition, the manifold absolute pressure sensor detects the intake manifold pressure. This information is used to diagnose EGR valve assembly operation.

    5. A blowby gas ventilation system is used. This system reduces emissions by forcibly drawing blowby gas, which includes a large amount of HC, into the intake manifold for combustion.

    6. The evaporative emission control system takes in fuel vapors generated inside the fuel tank into the canister, preventing them from being released into the atmosphere. The ECM controls the purge VSV in accordance with the driving conditions in order to direct the fuel vapors into the engine, where they are burned.