Denso has released a video which explains the vital job in managing emissions and performance that oxygen sensors fulfil. The 10 minute, comprehensive presentation answers some of the key questions relating to their role: 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.
Overview of oxygen sensors
Vehicle manufacturers must adhere to stricter emissions targets, and the sensors themselves allow the engine control unit to perform a growing list of tasks.
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 hold the alias of lambda sensors.
Fuel combustion creates harmful pollutants, not just for the environment, but for our own health. The three most dangerous – carbon monoxide, particulates and oxides of nitrogen – need to be controlled and reduced.
For this reason, 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: when a motorist wants or needs more power, like when accelerating, 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.
Oxygen sensors are one of the most important elements within modern engine management systems, and while Denso has outlined their significance, the video will offer more important and useful information. A greater understanding of how they work, their functions and efficiency will bode well for technicians undertaking work that enters their workshop.