Step by step guide on how an automotive oxygen sensor works, this article pertains to most vehicles.
Step 1 - An oxygen sensor is an electronic component that is designed to measure levels of oxygen in an automotive engine exhaust system.
Step 2 - Typically, the oxygen sensor is mounted
to the exhaust system tube or on the side of a catalytic converter, with the sensor
part inside the tube. This measures the oxygen mixture by generating a small amount
of electricity due to the difference in atmosphere, oxygen and carbon dioxide. The
computer PCM monitors this voltage and adjusts fuel delivery accordingly. Oxygen
sensors can usually be found in the exhaust pipe near the engine (primary sensor)
although sometimes they are mounted in the exhaust manifold itself where the exhaust
pipe connects. Sensors found after or on the catalytic converter is the secondary
unit.
Step 3 - The sensor's job is to measure the amount of oxygen
required to burn any fuel remaining in the exhaust stream and relay that information
back to the computer PCM (Powertrain Control Module) where it is compared with other
live information so that adjustments can be made to maximize fuel efficiency and
power via proper air-fuel mixture and ignition timing in the engine. Oxygen sensors
do this through a chemical reaction inside the sensor itself; in this article we
will explain the evolution and application of this very important piece of the fuel
injection puzzle. Oxygen sensors work through a chemical reaction. The core or element
of the sensor is Zirconia ceramic with a thin layer of platinum. Since these materials
are reactive and are applied as layers they will eventually wear out reducing their
efficiency.
Step 4 - The voltage created by the sensor is then
relayed to the computer where it will compare it with other live information to
make the necessary mixture and timing adjustments. The oxygen sensor is in continuous
communication with the engine control unit giving it the information necessary to
adjust fuel delivery for optimum combustion.