СИСТЕМА SFI


  1. FUNCTION


    1. This system ensures the negative pressure necessary for the brake booster when sufficient negative pressure is not being produced by the intake manifold, such as when the Dual Variable Valve Timing-intelligent (Dual VVT-i) system or Electronic Throttle Control System-intelligent (ETCS-i) system is malfunctioning.

    2. The negative pressure necessary for the brake booster is produced by using an ejector that utilizes the Venturi effect and by introducing outside air into the ejector.

      A01KX7VC01
      *1 Vacuum Check Valve *2 Brake Booster Assembly
      *3 No. 1 Vacuum Switching Valve Assembly (for Ejector) *4 Brake Booster Vacuum Ejector

    3. When the engine is started, negative pressure from the intake manifold travels to the brake booster via pipe A.

    4. When negative pressure in the intake manifold is low, the ECM opens the VSV, introducing outside air into the ejector. The flow speed of this outside air generates a high level of negative pressure. This negative pressure travels to the brake booster via pipe B.

    5. When the VSV is open, the amount of air intake increases owing to bypass air traveling through the ejector. Because of this, the ECM corrects the opening amount of the throttle valve, and controls fluctuations in the engine speed in accordance with the opening and closing of the VSV.

      A01KXMFC01
      *1 Engine *2 ECM
      *3 Intake Manifold *4 Throttle Control Motor
      *5 Air Cleaner *6 No. 1 Vacuum Switching Valve Assembly (for Ejector)
      *7 Brake Booster *8 Vacuum Check Valve
      *9 Brake Booster Vacuum Ejector - -
      *a Pipe A *b Pipe B
      *c Venturi - -