SFI SYSTEM


  1. FUNCTION


    1. The Direct Ignition System (DIS) is used. Each ignition coil assembly is equipped with a built-in igniter, and one ignition coil assembly is provided for each cylinder. The ECM performs ignition timing control in accordance with the engine status based on the signal from the sensors.

    2. The ECM calculates the most appropriate ignition timing and the time that current is applied to the primary windings of the ignition coil based on the signals sent from various sensors. The ECM then sends an ignition command signal to the igniter of the ignition coil assembly. The default ignition timing is set at 5° before top dead center (BTDC).

    3. The ignition timing is obtained using the following formula:

      Ignition timing = A or B + C

      Where: A: Base ignition timing, B: Basic advance, C: Compensation advance

      Ignition Timing Controls
      A. Fixed advance characteristics The base ignition timing is 10° BTDC. It is fixed to 5° BTDC while the engine is starting.
      B. Basic advance characteristics The most appropriate ignition timing is selected from a map based on the signals from a variety of sensors.
      C. Compensation advance characteristics The ignition timing is advanced or retarded depending on the signals from a variety of sensors.
      C-1. Warm engine advance characteristics When the engine coolant temperature is low, the ignition timing is advanced in accordance with driving conditions to enhance drivability.
      C-2. Idle stabilization advance characteristics If the idle speed drops, the ignition timing is advanced to stabilize the idle speed. If the idle speed increases, the ignition timing is retarded.
      C-3. Transition compensation retard To prevent knocking, the ignition timing is retarded during sudden acceleration at a coolant temperature of 60°C (140°F) or more.
      C-4. Timing retardation during fuel cut recovery The ignition timing is retarded when the engine is recovered from fuel cut control, reducing shock.
      C-5. Retard when accelerating The ignition timing is temporarily retarded during acceleration to enhance drivability.
      C-6. Knock compensation retard If knock occurs, the ignition timing is corrected based on the signal from the knock control sensor.
      C-7. Timing advance during EGR adjustment Adjustment is performed to advance the ignition timing in accordance with the EGR volume.