Exhausts have four main functions:
- to control noise
- to direct exhaust fumes away from passengers
- to improve the performance of the engine
- to improve fuel consumption.
An exhaust is a series of pipes that links the engine to a silencer and a catalytic converter.
The tailpipe is the part of the exhaust that you can see extending from the back of the car. The silencer joins onto the tailpipe, then a series of further pipes joins the silencer to the catalytic converter and then the engine.
The silencer contains metal plates or tubes that have a series of holes bored into them. Exhaust gases leave the engine at very high pressures, and the holes in the silencer help to reduce that pressure so that they leave the car more quietly.
The lambda sensor measures and sends oxygen content information back to the engine management system which makes second by second adjustments to the fuel and air mix being used by the engine. This makes sure that harmful gases are burnt efficiently in the catalytic converter. If the lambda sensor becomes faulty, the engine management system sends a default amount of fuel to the chamber – it’s as if you are driving with the ‘choke out’. You may be using more fuel than necessary and might notice your car is not running as smoothly.