How Does an Exhaust Work?

Installing an aftermarket exhaust system is a fairly common sports car upgrade. For those buying used vehicles, the overall health of the exhaust system is a key deciding factor. In order to understand this, you need to understand how an exhaust works.

In this article, we describe the various components of the exhaust system of a car. These components are as follows:

1. Exhaust manifolds

Exhaust manifolds make sure that the combustion gases go into the exhaust system. Depending on the size of the engine of your car, the exhaust system might have two exhaust manifolds. As the fundamental objectives dictate, exhaust manifolds connect directly to the engine of the vehicle.

An exhaust manifold has passages that improve the flow of the exhausts. In order to do this job effectively, exhaust manifolds have smooth and curved passages. Exhaust manifolds can be made of steel, aluminium, stainless steel, or cast iron.

You need exhaust manifolds to function properly. If you are buying a used car, then get them inspected so that common problems like cracking, warping, and leakages can be identified.

2. Oxygen sensors

In modern cars, exhaust systems need to measure how much oxygen is present in the exhaust system and inform the in-vehicle computer. The in-vehicle computer uses this information to calculate how much fuel it should allow into the engine. This computation allows the vehicle to achieve optimal fuel economy and performance. Oxygen sensors present in the exhaust system gather this information about the presence of oxygen, as a result, these are key components.

Exhaust systems in vehicles with 4-cylinder engines have two oxygen sensors. One of these is located in the exhaust manifold in front of the catalytic converter, which is another key component of the exhaust system. The other sensor is located on the exhaust pipe after the catalytic converter.

If you have four oxygen sensors in cars with V6 or V8 engines. two censors are situated before the catalytic converter, with one each on each cylinder bank. The location of the other two oxygen sensors is after the catalytic converter, and these too are situated on the respective cylinder banks.

3. Catalytic Converters

Catalytic converters in an exhaust system help the car meet regulatory standards concerning emissions. These converters use a filtering process to reduce the harmful chemicals released in the environment by the exhaust system.

A catalytic converter is located between the exhaust manifold and the muffler, which is another key component of the exhaust system.

Catalytic converters use metals or chemicals as catalysts. Catalysts facilitate chemical reactions, however, they don’t get impacted by those reactions. Catalysts could be precious metals like platinum, palladium, or rhodium. Aided by the heat, these catalysts cause chemical reactions. These reactions convert carbon monoxide and other hydrocarbons to produce water vapor and carbon dioxide.

Carbon dioxide is less harmful to the environment than carbon monoxide. By converting harmful substances to less harmful ones, catalytic converters help your vehicle meet emission-related regulations.

4. Resonators

A resonator in an exhaust system does what a muffler does to a lesser extent. Exhaust gases travel through a resonator, which is an empty chamber. These gases bounce around within the resonator. This movement reduces some of the noise, however, it doesn’t eliminate it completely. The location of a resonator can be either before the muffler or after it.

5. Exhaust pipes

Exhaust pipes connect the entire exhaust system from one end to the other. Also called exhaust downpipes, such pipes allow the exhaust gas to travel efficiently through the exhaust system. This way, exhaust pipes keep hot exhaust gases away from the heat-sensitive components in the engine compartment.

Manufacturers use steel to manufacture exhaust pipes. To make exhaust pipes corrosion-resistant, they might use aluminized steel or stainless steel.

Exhaust pipe manufacturers might use the “mandrel bending” technique to manufacture exhaust pipes. Mandrel bending has the effect of making the exhaust pipe like a flexible straw, which helps to reduce back pressure. This technique also reduces the turbulence in the flow of exhaust gases.

6. Muffler

The muffler in an exhaust system reduces the noise created by the engine of your vehicle. You typically see two types of mufflers. In one type of muffler, baffled chambers cause the sound to bounce off the baffles. This reduces noise.

The other type of mufflers channels the exhaust gases through a perforated pipe. Manufacturers use metal, fiberglass, or other materials that absorb sound to build these pipes. The second type of mufflers also helps to reduce back-pressure.

7. Tailpipes

This is the only part of an exhaust system that you can see from the outside. A tailpipe is located after the muffler, and you can see it around the rear bumper of the vehicle. Tailpipes release the exhaust gases outside, and some vehicles might have more than one of them.

A tailpipe could have a straight or angled cut in the end. Some tailpipes have a diameter that’s larger than the pipes in the rest of the exhaust system, therefore, they reduce the pressure of the exhaust gas.