DENSO has released a video which explains the vital job in managing emissions and performance that oxygen sensors fulfil.

The 10-minute presentation answers some of the key questions relating to their role, such as: how do they work? How do they influence the air/fuel ratio? How do they maximise the efficiency of the modern combustion engine? The animation, uploaded to DENSO Europe’s YouTube Channel, explains how oxygen sensors have been invaluable to engine management systems for the last four decades.

Oxygen sensors are found within the exhaust system, and they are designed to measure oxygen content in the outgoing exhaust gases, which is directly related to the air/fuel mixture at the engine intake. The most efficient combustion is 14.7: 1 – or lambda 1 – hence why oxygen sensors are often called lambda sensors.

It is vital that the air/fuel ratio of the mixture remains as close to lambda 1 as possible; however, that is not always possible such as when a motorist wants or needs more power. Here the engine will require a mixture that has a slight excess of fuel. Alternatively, when coasting, for example, the engine will require a lean mixture which will contain very little fuel.