SFI SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the 1NR-FE engine control system are as follows.

      Components 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.
      Crank Position Sensor [Rotor Teeth] MRE (Magnetic Resistance Element) Type [36 - 2] 1 This sensor detects the engine speed and the crank angle.
      Cam Position Sensor (No. 1 Crank Position Sensor) [Rotor Teeth] MRE (Magnetic Resistance Element) Type [3] 2 This sensor performs cylinder identification and detects the VVT angle.
      Knock Control Sensor Built-in Piezoelectric Element Type (Flat Type) 1 This sensor detects an occurrence of engine knocking indirectly from the vibration of the cylinder block caused by the occurrence of engine knocking.
      Intake Mass Air Flow Meter Sub-assembly Hot-wire Type 1 This sensor uses a built-in hot-wire to directly detect the intake air mass.
      E. F. I. Vacuum Sensor Assembly Semiconductor Silicon Chip Type 1 This sensor uses built-in semiconductors to detect the intake manifold pressure.
      Throttle Body with Motor Assembly Throttle Position Sensor Non-contact Type 1 This sensor detects the throttle valve opening angle.
      Oxygen Sensor Cup Type with Heater 1 This sensor detects the oxygen concentration in the exhaust emission by measuring the electromotive force generated in the sensor itself.
      Air Fuel Ratio Sensor Planar Type with Heater 1 As with the oxygen sensor, this sensor detects the oxygen concentration in the exhaust gas. However, it detects the oxygen concentration in the exhaust gas linearly.
      Accelerator Pedal Sensor Assembly Non-contact Type 1 This sensor detects the amount of pedal effort applied to the accelerator pedal.
      Fuel Injector Assembly 8-hole Type 4 The fuel injector assembly is an electromagnetically-operated solenoid with a nozzle which injects fuel in accordance with signals from the ECM.
      E. F. I. Engine Coolant Temperature Sensor Thermistor Type 1 This sensor detects the water temperature by means of an internal thermistor.

  2. SYSTEM CONTROL


    1. The engine control system of the 1NR-FE engine has the following systems.

      Components Function
      Sequential Multiport Fuel Injection (SFI)

      • An L-type SFI system is used, the intake air mass is detected with a hot-wire type intake mass air flow meter sub-assembly.

      • The fuel injection system is a sequential multiport fuel injection system.
      Electronic Spark Advance (ESA) The ECM determines the optimal ignition timing in accordance with the signals received from the sensors and sends an ignition (IGT) signal to the igniter. The ECM corrects ignition timing in response to engine knocking.
      Electronic Throttle Control System-intelligent (ETCS-i) Optimally controls the throttle valve opening in accordance with the amount of accelerator pedal effort, the throttle valve opening control request from the ECM, and the condition of the engine and the vehicle.
      Dual Variable Valve Timing-intelligent (VVT-i) Regulates operation of the intake and exhaust camshafts to ensure optimal valve timing in accordance with engine operating conditions.
      Fuel Pump Control Fuel pump operation is controlled by signals from the ECM. The fuel pump is stopped when the SRS airbags deploy.
      Cooling Fan Control The ECM steplessly controls the speed of the fan via the cooling fan ECU in accordance with the engine coolant temperature, vehicle speed, engine speed, and air conditioning conditions*1. As a result, good cooling performance is achieved.
      Starter Control (Cranking Hold Function)*2 Once the engine switch is pushed, this control operates the starter until the engine starts.
      Air Fuel Ratio Sensor and Oxygen Sensor Heater Control Maintains the temperature of the air fuel ratio sensor or oxygen sensor at an appropriate level to increase the detection accuracy of the exhaust gas oxygen concentration.
      Engine Immobiliser Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.
      Air Conditioning Cut-off Control*1 By turning the compressor with pulley assembly on or off in accordance with engine operating conditions, drivability is maintained.
      Brake Override System Restricts the driving torque when the brake pedal is depressed while the accelerator pedal is depressed. (For the Activation Conditions and Inspection Method, refer to the repair manual)

      *1: Models with air conditioning system

      *2: Models with entry and start system

  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 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.