SFI SYSTEM


  1. CONSTRUCTION


    1. A planar type air fuel ratio sensor and a cup type heated oxygen sensor are used. The basic construction of the heated oxygen sensor and the air fuel ratio sensor is the same. However, they are divided into the cup type and the planar type, according to the different types of heater construction used.

    2. The planar type air fuel ratio sensor uses alumina, which excels in heat conductivity and electrical insulation, to integrate the sensor element with a heater, thus improving the warm-up performance of the sensor.

    3. The cup type heated oxygen sensor contains a sensor element that surrounds the heater.

      A0121MEC01
      *1 Air Fuel Ratio Sensor (Planar Type) *2 Heated Oxygen Sensor (Cup Type)
      *3 Diffusion Resistance Layer *4 Alumina
      *5 Platinum Electrode *6 Sensor Element (Zirconia)
      *7 Heater *8 Atmosphere

    4. As illustrated below, the conventional heated oxygen sensor is characterized by a sudden change in its output voltage at the threshold of the stoichiometric air fuel ratio (14.7:1). In contrast, the air fuel ratio sensor data is approximately proportionate to the existing air fuel ratio. The air fuel ratio sensor converts the oxygen density to current and sends it to the ECM. As a result, the detection precision of the air fuel ratio has been improved. The air fuel ratio sensor data can be viewed using the Global TechStream (GTS).

      A0121KGE58