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Car Exhausts

car exhaust

Some information about car exhaust.

Exhausts have four main functions

  1. to control noise,
  2. to direct exhaust fumes away from passengers,
  3. to improve the performance of the engine,
  4. and 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.

Exhausts can corrode from both the inside and outside. How long your exhaust lasts for depends on how far and how often you drive your car rather than the length of time it has been fitted. Vehicles used for short trips around town tend to corrode their exhausts in a much shorter time and distance than cars used predominately for long journeys.

The lambda sensor

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.

How does my exhaust system work?

It's only when you hear or drive a car with a damaged silencer that you realise what a huge difference it makes to reducing noise levels.

And the way a silencer works is quite fascinating. It contains a deceptively simple set of tubes that are finely tuned to reflect the sound waves produced by an engine so that they cancel each other out.

If there is a hole in the silencer then the sound waves are no longer forced through the tubes and escape outside - increasing the noise level.

Other key components of your exhaust include exhaust pipes that are designed specifically for each car model and route exhaust fumes to the exit at the back of the car.

The exhaust manifold acts as a funnel. It collects exhaust gases from all cylinders of the engine then releases them through a single opening, often referred to as the front pipe.

The exhaust centre section works with the silencer to reduce noise and the tail pipe at the rear carries gases away from the vehicle. All of the components of an exhaust system are connected with a series of clamps, hangers, flanges and gaskets.