СИСТЕМА SFI


  1. FUNCTION OF MAIN COMPONENTS


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

      Component Outline Quantity Function
      ECM 32-bit CPU 1 The ECM performs overall control of the engine control system to suit the operating conditions of the engine in accordance with the signals provided by the sensors.
      Intake Mass Air Flow Meter Sub-assembly Hot-wire Type 1 This sensor has a built-in hot-wire to directly detect the intake air mass.
      Intake Air Temperature Sensor Thermistor Type 1 Detects the intake air temperature by means of an internal thermistor.
      Engine Coolant Temperature Sensor Thermistor Type 1 Detects the engine coolant temperature by means of an internal thermistor.
      Crank Position Sensor [Rotor Teeth] Pick-up Coil Type [36-2] 1 Detects the engine speed and performs cylinder identification.
      Cam Position Sensor [Rotor Teeth] Magnetic Resistance Element (MRE) Type [3] 2 (1 each bank) Performs cylinder identification.
      Accelerator Pedal Position Sensor Linear (Non-contact) Type 1 Detects the amount of pedal effort applied to the accelerator pedal.
      Throttle Control Motor DC Motor 1 Regulates the opening of the throttle valve in accordance with the signals from the ECM.
      Throttle Position Sensor Linear (Non-contact) Type 1 Detects the throttle valve opening angle.
      Knock Control Sensor Built-in Piezoelectric Type (Non-resonant Type/Flat Type) 2 (1 each bank) Indirectly detects an occurrence of engine knocking from the resulting vibration of the cylinder block.
      Camshaft Timing Oil Control Valve Assembly Solenoid Type 2 (1 each bank) Changes the oil passage to the VVT-i controller in response to signals from the ECM.
      Air Fuel Ratio Sensor Heated Type (Planar Type) 2 (1 each bank) Detects the oxygen concentration in the exhaust emissions as with the oxygen sensor. However, it detects the oxygen concentration in the exhaust emissions linearly.
      Oxygen Sensor Heated Type (Cup Type) 2 (1 each bank) Detects the oxygen concentration in the exhaust emissions by measuring the electromotive force which is generated in the sensor itself.
      Fuel Injector Assembly 12-hole Type 6 (3 each bank) The fuel injector assembly is an electromagnetically-operated nozzle which injects fuel in accordance with signals from the ECM.
      Ignition Coil Assembly Type with Igniter 6 (3 each bank) Incorporates an igniter and provides a high level of voltage necessary for ignition in accordance with signals from the ECM.
      Spark Plug Long-reach Type 6 (3 each bank) Sparks a high level of voltage from the ignition coil assembly inside the cylinder.

  2. SYSTEM CONTROL


    1. The engine control system has the following features. The ECM controls these systems:

      System Outline
      Sequential Multiport Fuel Injection (SFI)

      • An L-type SFI system directly detects the intake air mass with the hot wire type mass air flow meter.

      • The fuel injection system is a sequential multiport fuel injection system.

      • Fuel injection takes 2 forms:


        • Synchronous injection, which always takes place with the same timing in accordance with the basic injection duration and additional correction based on signals provided by the sensors.

        • Non-synchronous injection, which takes place at the time of an injection request based on signals provided by the sensors is detected, regardless of the crankshaft position.

      • Synchronous injection is further divided into group injection during a cold start, and independent injection after the engine is started.
      Electronic Spark Advance (ESA)

      • Ignition timing is determined by the ECM based on signals from various sensors. The ECM corrects ignition timing in response to engine knocking.

      • This system selects the optimal ignition timing in accordance with signals received from the sensors and sends ignition signals (IGT) to the igniters.
      Electronic Throttle Control System-intelligent (ETCS-i) Optimally controls the throttle valve opening in accordance with the amount of accelerator pedal effort and the condition of the engine and the vehicle.
      Variable Valve Timing-intelligent (VVT-i) Regulates operation of the intake and exhaust camshafts to ensure an optimal valve timing in accordance with the engine conditions.
      Air Control Induction System (ACIS) The intake air passages are switched based on engine speed and throttle valve opening angle to provide high performance in all engine speed ranges.
      Fuel Pump Control

      • Fuel pump speed is controlled by the fuel pump relay and the fuel pump resistor.

      • The fuel pump is stopped when the Supplemental Restraint System (SRS) airbags are deployed.
      Air Conditioning Cut-off Control*1 By turning the air conditioning compressor assembly on or off in accordance with the engine condition, driveability is maintained.
      Air Fuel Ratio Sensor and Oxygen Sensor Heater Control Maintains the temperature of the air fuel ratio sensors or oxygen sensors at an appropriate level to increase the detection accuracy of the exhaust gas oxygen concentration.
      Brake Override System The driving torque is restricted when both the accelerator and brake pedals are depressed. (For the activation conditions and inspection method, refer to the Repair Manual.)
      Starter Control (Cranking Hold Function)*2 Once the engine switch is pushed, this control continues to operate the starter until the engine is started.
      Engine Immobiliser Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.

      *1: Models with air conditioning system

      *2: Models with entry and start system

  3. FAIL-SAFE


    1. When the ECM detects a malfunction, the ECM stops or controls the engine in accordance with the data already stored in memory.

  4. DIAGNOSIS


    1. When the ECM detects a malfunction, the ECM diagnoses and memorizes the failed section.