Oxygen Sensor

Oxygen Sensor

The oxygen sensor is located in the exaust manifold before the catalytic converter. This is a ziconia type oxygen sensor with four wires. 2 wires for the heater circuit and a signal and a ground. The oxygen sensor needs to reach a tempeature of about 300 degrees celsius to work, therefore the heater is in the oxygen sensor for it to heat up quickly. This a very important sensor in the engine fuel control system. the sensor produces a voltage signal that recognises the amount of oxygen in the exhaust. More air will tell the engine is runnig lean and less air will tell the ecu that the engine is runnig rich. In closed loop the sensor goes rich and lean to control emissions. Heated oxygen sensor are good as it gets to closed loop quicker which improves fuel economy and reduces emmisions.

A- protector
B-Ziconia sensor tip
C-Heater
D-sealing ring
E-Housing
F-Protective sleeve
G-21% outside oxygen to 2% exhaust oxygen runs lean
H-21% outside oxygen to 0% exhaust oxygen runs preferred
I-21% outside oxygen to 2% exhaust fuel runs rich

Voltage ranges from 0.2 volts (lean) to 0.8 volts (rich). A perfectly balanced fuel mixture gives an average reading of around 0.45 volts.

We carried out the experiment by connecting a multimeter to read voltage to the oxygen sensor. We then heated it up by a LPG gas torch and saw how it went rich when we had the torch close to it and and how it went lean when we took the torch away. when we had the flame on the sensor we got 0.9 v which told us that its detecting that its a rich condition. When we take the flame away the voltage drops to 0.2v this shows us thats its a lean condition.

I tried uploading the video here but did not work so i uploaded it on youtube. this is the link to it. http://www.youtube.com/watch?v=zejlhtYntsk. it clearly shows how we a get a voltage to a rich and lean (no flame to sensor) condition.