EMISSION CONTROL SYSTEM GENERAL


  1. OUTLINE


    1. TWCs (Three-Way Catalytic converters) are used in the exhaust manifold and the front exhaust pipe assembly.

    2. An EGR control, which reduces the combustion temperature by recirculation of exhaust gas and improves fuel economy, is used.

    3. The ECM performs the 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.

    4. A blowby gas ventilation system, which efficiently ventilates blowby gas containing HC from the crankcase, is used.

    5. An evaporative emission control, which regulates the purge flow of evaporative emission (HC) into the canister in accordance with the engine conditions, is used.

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