1. What does an oxygen sensor do?
Also known as a ‘lambda sensor’ or an ‘O2 sensor’, an oxygen sensor ensures ideal conditions for the catalytic converter by providing constant measurement of the air-fuel ratio. The optimum air to fuel mixture for an internal combustion engine is one that has a ratio of 14.7kg air to 1kg fuel: This specific air-fuel combination is called the stoichiometric ratio, which corresponds to a value of lambda 1. This ratio, however, isn’t automatically guaranteed, which is the reason why oxygen sensors play such an important role.
2. How do oxygen sensors work?
Oxygen sensors measure the percentage of oxygen in the exhaust system and then report this information back to the vehicle’s engine control unit (ECU). Often, the air-fuel mixture is either too rich or too lean for the catalytic converter to do its job properly. If the mixture is too rich, the exhaust system contains not enough oxygen, while if the mixture is too lean, there is too much oxygen present. In both cases, ultimately, an efficient function of the catalyst is not possible. To counter this, the oxygen sensor relays its findings to the ECU which then adjusts the air-fuel mixture as close to lambda 1. This results in more efficient combustion, which not only benefits the environment by decreasing emissions, but also results in fuel savings and a reduction in engine wear and tear.
