Exhaust system isn’t a rocket science and has simple function that every car owner must know.
Similar to its counterpart – the air intake system, where air is sucked into the engine’s combustion chamber to produce power, the exhaust system emits the waste gasses from the combustion process into the air.
So in this short post, I will discuss the exhaust system – particularly its basic components and their functions.
What is an Exhaust System?
The exhaust system is the last “stroke” or process in an internal combustion engine. Lets say your engine is a 4-stroke engine, the engine strokes or processes include:
- Intake – suction of air
- Compression
- Combustion
- Exhaust – outlet of gasses
There are three key functions for this system. One is to carry away emissions. Second is to filter or even eliminate harmful and toxic gasses. And lastly, to control or minimize the exhaust noise as much as possible.
Like the air intake system, the exhaust system also contain several stages. Let me break it down for you one-by-one.
Exhaust Manifold
Also called as exhaust headers, it’s an assembly designed to collect and divert exhaust gas from 4 to 8 cylinders (depending on the engine) into one single exit pipe. Most manifolds are made of cast iron.
Exhaust manifold do have design restrictions due to many reasons such as lack of enough engine space or has been designed to be cost-effective. Due to this fact, most manifolds do not provide the best efficient job in venting gasses from the engine.
While manifolds in most production cars are enough to achieve power, car enthusiasts will settle for more performance by upgrading to intake headers to achieve optimal flow of the exhaust gasses.
Oxygen Sensors
After the manifold, gasses will pass through your system’s first oxygen sensor. As its name suggest, it monitors the fuel to air ratio that passes the exhaust pipe.
Why is this important?
The sensor ensures if your engine emits rich or lean fuel and if it detects that the pipe passes more air, then it signals the fuel management system to inject more fuel into the combustion chamber, and vice versa.
There are other sensors in the exhaust system, and if they found any irregularities, they will set the check engine light which signals that you need to fix something.
But what about if the sensor itself is bad? Well, read this post and learn the symptoms of a bad oxygen sensor.
Catalytic Converter
Not all vehicles have catalytic converter, and some automobiles even have two catalytic converters. So what are this component for?
The main function of catalytic converter is to significantly reduce harmful emissions such as hydrocarbons (vaporized fuel), carbon monoxide and nitrogen oxide (NOx) into the atmosphere.
It converts this harmful gasses into a more environment friendly gasses such as carbon dioxide and water.
Catalytic converters (like other filters) do clogged up due to carbon build up. So you may need to clean this component for every 100,000 mileage.
How do you know if its time to clean your catalytic converter? An oxygen sensor will notify you once your converter is due for cleaning maintenance. You can clean this by using catalytic converter cleaners (disassembly needed) or by using carbon cleaning agents that are poured directly into the fuel tank.
Resonator
The purpose of resonator in exhaust system is to make sound waves that will bounce back and forth inside the chamber, which results the sound wave to cancel each other out.
What does this mean? It means that resonators can either dampen the noise or can even enhance the sound of the exhaust.
This is the reason why some car manufacturers decide to completely ignore installing resonators in some of their vehicles. But most cars today have resonators to reduce noise as mandated by local authorities.
Some car enthusiasts especially those who are into racing, delete their car’s resonator thinking that it can help improve performance and add some power, in addition of producing louder and aggressive sound.
Muffler
Probably the most well-known part of the exhaust system, a muffler or sometimes called as “silencer” is a device designed to further reduce exhaust noise.
In short, it compliments or supports the job of an exhaust resonator. It is a a noise-deadening component found in most production cars worldwide.
For car geeks like me, I might consider removing the mufflers in my cars to get that growling sound coming from the engine. A free-flowing muffler is my choice but a chambered type is not too far in my mind!
After the muffler would be the tail pipe, which is the last part of the exhaust system and where the fumes exits the car.
Here is a video that I made discussing the basics of exhaust system. The video is in Tagalog language but has English subtitle. Enjoy!
Image Credits:
Jason Swaby – Flickr
https://www.flickr.com/photos/jswaby/2935686824/
Official Gazette Executive Order No. 180, s. 1948
https://www.officialgazette.gov.ph/1948/10/02/executive-order-no-180-s-1948/
Jason Swaby – Flickr
https://www.flickr.com/photos/jswaby/2935686824/
Three-Way Catalytic Converter
https://commons.wikimedia.org/wiki/File:DodgeCatCon.jpg
Exhaust Manifold
https://commons.wikimedia.org/wiki/File:Exhaust_manifold.jpg
Lain Cameron from Ellon Scotland
https://commons.wikimedia.org/wiki/File:Engine_LHS_Exhaust_Manifold_(40561340735).jpg
Ermestp Andrade -flckr
https://www.flickr.com/photos/dongkwan/5587768842
