SFI SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


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

      Components Outline Quantity Function
      ECM 32-bit CPU 1 Optimally controls 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 Air Flow Meter Hot-wire Type 1 Uses a built-in hot-wire to directly detect the intake air mass.
      Intake Air Temperature Sensor Thermistor Type 1 Detects the intake air temperature.

      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)

      Magneto-Resistance Element (MRE) Type

      (3)

      		 1 Performs cylinder identification.
      Throttle Body Assembly Throttle Position Sensor Linear (Non-contact) Type 1 Detects the throttle valve opening angle.
      Throttle Control Motor DC Motor 1 Regulates the opening of the throttle valve in accordance with the signals from the ECM.
      Knock Control Sensor Built-in Piezoelectric Element Type (Flat Type) 1 Detects an occurrence of engine knocking indirectly from the vibration of the cylinder block caused by the occurrence of engine knocking.
      Engine Coolant Temperature Sensor Thermistor Type 1 Detects the engine coolant temperature.
      E.F.I. Engine Coolant Temperature Sensor Thermistor Type 1
      Air Fuel Ratio Sensor Heated Type (Planar Type) 1 Detects the oxygen concentration in the exhaust emissions by measuring the electromotive force which is generated in the sensor itself.
      Oxygen Sensor Heated Type (Cup Type) 1
      E.F.I. Vacuum Sensor Assembly Semiconductor Silicon Chip Type 1 Detects the pressure in the intake manifold and sends signals to the ECM.
      EGR Valve Assembly Step Motor Type 1 Opens and closes based on signals from the ECM and controls the flow rate of the exhaust gas in the EGR bypass.
      Fuel Injector Assembly 12-hole Type 4 This injector is an electromagnetically-operated nozzle which injects fuel in accordance with signals from the ECM.

  2. SYSTEM CONTROL


    1. The engine control system has the following features:

      Components Function
      Sequential Multiport Fuel Injection (SFI)

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

      • 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 selects 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 conditions.
      Variable Valve Timing-intelligent (VVT-i) Controls the camshaft (intake) to an optimal valve timing in accordance with the engine operating conditions.
      Cooling Fan Control Cooling fan operation is controlled by signals from the ECM based on the engine coolant temperature, air conditioning operation conditions, and hybrid system coolant temperature.
      Water Pump Control Engine water pump assembly operation is controlled by signals from the ECM.
      Fuel Pump Control

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

      • The fuel pump is stopped when any of the SRS airbags deploy.
      Dual-passage Cooling Control Divides the engine coolant system into 2 circuits, and depending on the engine conditions, maintains effective heater operation while reducing coolant flow through the engine.
      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 ability of the sensors to accurately detect the oxygen concentration.
      Exhaust Gas Recirculation (EGR) Control Based on the signals received from the sensors, the ECM determines the EGR volume in accordance with the engine operating conditions.
      Evaporative Emission Control The ECM controls the purge flow of evaporative emissions (HC) from the canister in accordance with the engine operating conditions.
      Fail-safe When the ECM detects a malfunction, the ECM stops or controls the engine according to the data already stored in memory.
      Diagnosis When the ECM detects a malfunction, the ECM records the malfunction and information that relates to the fault.

  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 will also store Diagnostic Trouble Codes (DTCs) of the malfunctions. The DTCs can be accessed by using the Global TechStream (GTS).

    3. For details, refer to the Repair Manual.