EMISSION CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


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

      Component Function
      Canister Contains activated charcoal to absorb the fuel vapor that is created in the fuel tank assembly.
      Purge VSV Opens in accordance with the signals from the ECM when the system is purging in order to send the fuel vapor that was absorbed by the canister into the intake manifold.
      ECM Controls the purge VSV in accordance with the signals from various sensors in order to achieve a purge volume that suits the driving conditions.
      Fresh Air Line Fresh air goes into the canister and the cleaned drain air goes out into the atmosphere.
      Canister Filter Prevents dust and debris in fresh air from entering the system.

  2. SYSTEM CONTROL


    1. Purge Flow Control


      1. When the engine has reached a predetermined state [closed loop, engine coolant temperature above 60°C (140°F), etc.], stored fuel vapor is purged from the canister whenever the purge VSV is opened by the ECM.

      2. The ECM will change the duty ratio cycle of the purge VSV, thus controlling purge flow volume. Purge flow volume is determined by intake manifold pressure and the duty ratio cycle of the purge VSV. Atmospheric pressure is allowed into the canister to ensure that purge flow is constantly maintained whenever purge vacuum is applied to the canister.

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