Exhaust System Guide for the automotive automobile industry

What are Exhaust Systems?

Automotive exhaust systems are put in place in vehicles to channel out the gases produced during the combustion process within the engine. Manufacturing and production fitting of these depend on the type of vehicle and the amount of energy it uses up. 

Automobile companies can customize every aspect of the production pipeline, right from the cylindrical grid, pistons as well as end exhaust pipes. These standards are followed automobile industry-wide and are provided to every automobile maker throughout the world.

Exhaust System Types

Automotive exhaust comes in various shapes and sizes. There is a different version available for different types of vehicles. The exhaust of a high-performance sporting vehicle will be different from the exhaust of a high-performance pulling truck. These key differences are the mark-up in the production process.

Some different types of exhaust systems are: –

• Single Exit Pipe: The most common type of exhaust system, found in almost all commercial vehicles. A single pipe is responsible for circulating the gas.
• Dual Rear Exit: Two exhaust pipes are put on the opposite side of the vehicle to give it a sportier feel. This also enhances the sound of the engine.
• Opposite Dual Exhaust: These wrap around the vehicle wheel to carry out an extra filtration process.
• Dual Side Exhaust: Two pipes next to each other on the same side, pump out gases more efficiently than single exit pipes.
• High Performance: The more expensive option, but these are the best at filtering the gases out and providing efficient system performance.

The basic jest of the matter is that all of the automobile industry uses exhaust systems that are based on the same design principles and are varying in some minute details. The above-mentioned types are all the collective systems that are available in the market today. 

Exhaust System Design 

The design process of an exhaust system for automobiles depends on the engine components and the type of vehicle which is to use it.  Based on the due diligence, exhaust systems can be designed for the following vehicles: –

• Motorcycles: Earlier, motorcycles used to come with a single exhaust and muffler which increased performance but caused a lot of noise. Automobile companies then began finding different ways to increase performance. Nowadays a twin-cylinder bike has an independent exhaust system which is a two-in-one single exhaust. This is a significant increase in performance as compared to previous years.
• Trucks: Mostly the exhausts of these vehicles are hidden below the chassis. The silencers are coated with a perforated metal sheet to prevent any accidental heart incident. American trucks have their exhaust vertically upward, this blows the toxic gases away from people.
• Two-Stroke Engines: These types of engines have an expansion chamber that uses pressure to create a high amount of air and fuel into the cylinder during the intake stroke.
• Marine Engines: Marine engines have their room in a shipping vessel which is serviced by engineers throughout its run. The exhaust pipe is used to stop the engine from overheating.
• Outboard Motors: The exhaust system is a vertical passage that passes through the engine structure. It aims to reduce the water noise which blows out underwater. 

These are some of the types of engines and their corresponding exhaust mechanisms. These are designed for their specific vehicle counterparts are have significant guidelines to follow to make sure the automobile industry standards are met and the emissions are below the limit. 

Exhaust System Components

There are certain key components in an exhaust system that make it do what it does, the essential components are similar in all of the exhaust systems whether it’s high-performance or common use vehicles. These are the following: –

• Tailpipe and Exhaust: Basic component in any exhaust system. The tailpipe runs towards the back of the vehicle and is the end part of the exhaust system. It is also equipped with a silencer to reduce the noise and the final opening provides a last-minute reduction in pressure before the gas comes out.
• Catalytic Converter: This is the component that removes the harmful hydrocarbons and carbon monoxides. They work by converting these harmful components into water and carbon dioxides. Emission control policies have made it mandatory to use catalytic converters in exhaust systems with high flow rates to convert the maximum number of emissions before releasing them into the atmosphere.
• Exhaust Pipe: The individual components of an exhaust system are connected by piping. The diameter of the outer hole depends on the RPM of the engine and is specifically designed keeping those in mind.
• Muffler: It decreases the amount of noise coming from the engine. They are made with fiberglass materials and helps keep the sound at bay.
• Turbocharger: It contains a bunch of fans that increases the amount of air that is coming into the engine, which adds more power to it. This increases the efficiency of the vehicle.
• Lake Pipes: They allow lower suspension and sufficient height for effective engine tuning and provides the flexibility to swap out engine manifolds.

These basic key components collectively make up the entirety of the exhaust system of an automobile. The dimensions and overall integrity vary according to the kind of vehicle it is being made for; the blueprint of which gives the vehicle its signature engine sound and look. The working principle is the same for all the exhaust systems in any vehicle, which makes it a universally accepted design. The emissions from these exhausts have significantly improved in the last decade as the filtration process and the catalytic converters have improved providing less bulk and more eco-friendly conversion of byproducts.

Working of an Automotive Exhaust System

In automotive manufacturing, an ideal combustion engine would have converted every drop of fuel into energy without giving out any dirty bits in the form of gas. But the laws of thermodynamics don’t allow for such an ideal system to exist hence we have toxic products coming out of the exhaust every time an engine run. Some amount of fuel always remains unburnt or partially burnt and hence has to be evacuated out of the vehicle to keep it from breaking down.

The exhaust exits the engine and goes into the system through the exhaust manifold. It then travels through the interconnected pipes down the system until it exits through the tailpipe, put near the back bumper of the vehicle. The pipes help in cooling the exhaust, but they’re mostly a way for the exhaust to travel to the catalytic converter and muffler. The car industry design of this procedure has come a long way in just the last decade.

The catalytic converter has to be as close to the engine as possible because it isn’t fully functional until it rises to a desired operating temperature. In many cases, the manufacturer places the catalytic converter shortly after the manifold, so heat from the engine helps warm the catalytic converter and quickly bring it up to temperature.

After the gases pass through the catalytic converter, which will burn off and remove up to 90 percent of the exhaust’s toxins, the next step will be to filter out the sound of the engine. The muffler and resonator are usually situated right beyond the catalytic converter. This combination has many variations — some will soothe the exhaust as much as possible, while others are specifically tuned for aggressive tones. From there, the exhaust moves through the exhaust piping until it exits the vehicle.

All those chemicals inside an exhaust system make it wear out quite easily if not properly taken care of. A well-maintained exhaust system should last two to three years, but the pipes incur damage both inside and out. On the outside, they’re susceptible to road conditions, such as impact from debris and environmental factors, such as snow, ice, and road salt.

Internal degradation is a substantial problem when it comes to exhaust systems. There is no way of knowing if your piping is bad from the inside until its starts to show signs of rust from the outside as well. The continued use gives rise to acidic moisture which is extremely harmful to metals and makes them downright obsolete to be used again. Unfortunately, we cannot know or stop this internal rust from building up.

A rotting exhaust pipe can cause leakage problems and break the entire system. It is often coupled with a loud and chaotic banging sound which will give away the deficiency of the engine. But, if the leak occurs before the catalytic converter, then the issue is a major one as the toxic by-products aren’t being neutralized and are being directly released into the atmosphere. Due to this reason, regular maintenance of an exhaust system should be done and the piping, if possible, should be replaced every two to three years depending on the vehicle.

Conclusion

Automotive exhaust systems and auto components are designed based on the vehicle which is to be fitted with them, but the underlying principle remains the same. The cat converter is the most important part of this system as without it the system won’t even be a legal thing to use as per regulation and automobile manufacturing standards. The scope of this to reduced future environmental impact is an important thing to look forward to by the way technology is progressing.