SFI SYSTEM


  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 optimally controls the SFI, ESA and ETCS-i to suit the operating conditions of the engine in accordance with the signals provided by the sensors.
      Mass Air Flow Meter Sub-assembly Mass Air Flow Meter 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 This sensor detects the intake air temperature by means of an internal thermistor.
      Engine Coolant Temperature Sensor Thermistor Type 1 This sensor detects the engine coolant temperature by means of an internal thermistor.
      Crank Position Sensor [No. of Rotor Teeth] Magneto- Resistance Element (MRE) Type [36 - 2] 1 This sensor detects the engine speed and crank angle.
      Camshaft Position Sensor (Intake) [No. of Rotor Teeth] Magneto- Resistance Element (MRE) Type [3] 1 This sensor performs cylinder identification and detects the intake VVT angle.
      Camshaft Position Sensor (Exhaust) [No. of Rotor Teeth] Magneto- Resistance Element (MRE) Type [3] 1 This sensor detects the exhaust VVT angle.
      Accelerator Pedal Sensor Assembly Linear (Non-contact) Type 1 This sensor detects the amount of pedal effort applied to the accelerator pedal.
      Throttle Body with Motor Assembly Throttle Position Sensor Linear (Non-contact) Type 1 This sensor detects the throttle valve opening angle.
      Tumble Control Valve Position Sensor Linear (Non-contact) Type 1 Detects the tumble control valve opening angle.
      Knock Control Sensor Built-in Piezoelectric Type (Non-resonant Type/Flat Type) 1 This sensor detects engine knocking indirectly through the vibration of the cylinder block caused by engine knocking.
      Air Fuel Ratio Sensor Heated Type (Planar Type) 1 As with the heated oxygen sensor, this sensor detects the oxygen concentration in the exhaust gas. However, it detects the oxygen concentration in the exhaust gas linearly.
      Heated Oxygen Sensor Heated Type (Cup Type) 1 This sensor detects the oxygen concentration in the exhaust gas by measuring the electromotive force which is generated in the sensor itself.
      Fuel Injector Assembly 12-hole Type 4 The injector is an electromagnetically-operated nozzle which injects fuel in accordance with signals from the ECM.

  2. SYSTEM CONTROL


    1. The engine control system of the 2AR-FE engine has the following features.

      System Outline
      Sequential Multiport Fuel Injection (SFI)

      • This is an L-type SFI system. It directly detects the intake air volume with a hot-wire type mass air flow meter sub-assembly.

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

      • Fuel injection takes 2 forms:


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

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

      • Synchronous injection is further divided into grouped 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 determines the optimal ignition timing in accordance with the signals received from the sensors and sends ignition (IGT) signals to the igniters.
      Electronic Throttle Control System-intelligent (ETCS-i) Optimally controls the opening angle of the throttle valve in accordance with the accelerator pedal input and the engine and vehicle operating conditions.
      Dual Variable Valve Timing-intelligent (Dual VVT-i) Controls the intake and exhaust camshafts to the optimal valve timing in accordance with the engine operating conditions.
      Acoustic Control Induction System (ACIS) Switches the intake air passages based on engine speed and throttle valve opening angle to provide high performance in all engine speed ranges.
      Tumble Control System Fully closes the tumble control valves during cold start and cold running conditions to reduce exhaust emissions while the engine is cold.
      Fuel Pump Control

      • Fuel pump operation is controlled by signals from the ECM.

      • The fuel pump is stopped when an SRS airbag is deployed in a collision.
      Air Conditioning Cut-off Control By controlling the compressor with pulley assembly in accordance with the engine operating conditions, drivability is maintained.
      Cooling Fan Control Steplessly controls the speed of the fans in accordance with the engine coolant temperature, vehicle speed, engine speed, and air conditioning operating conditions. As a result, cooling performance is improved.
      Cranking Hold Function (Starter Control) Once the engine switch is pushed, this control operates the starter until the engine starts.
      Air Fuel Ratio Sensor and Heated Oxygen Sensor Heater Control Maintains the temperature of the air fuel ratio sensor or heated oxygen sensor at an appropriate level to increase the ability of each sensor to accurately detect the concentration of oxygen.
      Evaporative Emission Control The ECM controls the purge flow of evaporative emissions (HC) from the canister in accordance with the engine operating conditions.
      Drive Start Control If an abnormal shift (R to D/M, D/M to R, N to R, P to D/M, P to R) is detected while accelerating, a warning is displayed in the combination meter assembly and engine output is reduced to limit the acceleration, helping to avoid a collision.
      Engine Immobiliser Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.
      Fail-safe When the ECM detects a malfunction, the ECM stops or controls the engine according to the data stored in memory.
      Diagnosis When the ECM detects a malfunction, the ECM records the malfunction and information that relates to the fault.
      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)

  3. FAIL-SAFE


    1. When a malfunction of any of the sensors is detected, there is a possibility of an engine or other malfunction occurring if the ECM were to continue normal control. To prevent such a problem, the fail-safe function of the ECM either relies on the data stored in memory to allow the engine control system to continue operating, or stops the engine if a hazard is anticipated. For details, refer to the Repair Manual.

  4. DIAGNOSIS


    1. When the ECM detects a malfunction, the ECM records information related to the fault. Furthermore, the Malfunction Indicator Lamp (MIL) in the combination meter assembly illuminates or blinks to inform the driver.

    2. The ECM also stores Diagnostic Trouble Codes (DTCs) for malfunctions it has detected. The DTCs can be accessed by using the Global TechStream (GTS).

    3. For details, refer to the Repair Manual.