Why are Lambda Sensors fitted?
The most popular method used by vehicle manufacturers to reduce vehicle emissions is the three-way catalyst. This device converts the main pollutants in the exhaust gas to less harmful gases. However the three-way catalyst only works efficiently if the air-fuel ratio can be kept within very tight limits. This is where the lambda sensor comes in. The lambda sensor continuously detects oxygen in the exhaust gas. As the output from the sensor changes, the ECU changes the quantity of fuel injected which alters the mixture strength. This is known as closed-loop control and ensures that the mixture strength is always correct enabling optimum catalyst efficiency.
