PURGE CONTROL OPERATION [MZR 1.6]

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Determination of Purge Solenoid Valve Energization Time

•  The PCM determines the target purge flow amount according to engine operation conditions as the basic flow amount. The actual operation delays the build-up of operation current from coil inductance and corrects energization time according to fluctuation in battery voltage to cause operation delay based on the mass of the needle valve and plunger, and spring resistance. The lower the rate of battery positive voltage, the longer the energization time.

Calculation Method for Purge Flow Amount

•  The PCM determines the purge flow amount through the addition of each correction to the basic purge flow amount.

Contents

Calculation or determination method of purge flow amount and correction
Basic purge flow amount
The basic purge flow amount is determined by multiplying the intake temperature and barometric pressure correction to the purge mass volume which is calculated by multiplying the base purge rate and the intake air mass volume, which differs according to engine conditions.
correction
Purge start-up correction
Purpose: Prevents a sudden change in air/fuel ratio during the start-up of purge control.
During purge control start-up
•  When purge control operation conditions are met→correction
Volume decrease correction
Purpose: Decreases the amount of purge flow and stabilizes the air/fuel ratio.
When fuel injection control feedback correction value is unstable
•  According to the A/F sensor feedback condition


Operation condition

•  For purge control during normal driving, the PCM sends a duty signal to the purge solenoid valve when all of the following conditions are met.
―   Fuel injection control is in feedback zone or high load volume increase zone.
―  Airflow passage damage related DTC is not stored.
―  Engine coolant temperature is 80°{176°F} or more.