On every engine, whether it is a stationary engine or the engine that is powering your vehicle, some sort of exhaust system will be fitted to help remove the burnt gasses from the engine to a safe distance away from the engine and also in majority of cases to reduce the amount of noise emitted from the vehicle whilst driving. On a modern Vehicle the exhaust system is also fitted with Oxygen Sensors and Catalytic Convertors, which are both implemented to help control and reduce potentially harmful emissions from being emitted from your vehicle, and also to assist in the overall efficiency of your motor.
Whenever we perform a Service or Inspection on a vehicle this is an area that we are sure to pay close attention to. We inspect for the overall condition of the exhaust pipe to ensure there are no holes or cracks in the piping, the condition of the mufflers to ensure the baffles have not come loose which can cause an annoying rattle or even make your exhaust slightly louder, and finally all of the mounting components.
With such a strong aftermarket parts industry readily available sourcing aftermarket exhaust systems for vehicles has become a very common practice when repairing or replacing an exhaust system as majority of parts can be sourced for a competitive price without compromising for the overall quality and effectiveness of the system.
As well as standard Exhaust Systems there are also aftermarket options which can be applied in order to increase the flow of the exhaust and increase the overall performance of the vehicle. When modifying an exhaust system for performance purposes it is important that enough research is done to ensure the most can be achieved out of the system and when used for every day driving still complies with the rules and regulations in regards to Roadworthy Vehicles.
Different Components of Exhaust Systems
Exhaust Manifold – The Exhaust Manifold is the first component of the Exhaust System. The Manifold is mounted to the Head of the Engine and is the first part that the Exhaust Gasses will pass through.
Catalytic convertor – The Catalytic Convertor is fitted to all new vehicles in order to help reduce harmful emissions from entering the atmosphere. With a honeycomb like design internally fitted to the pipe, this is designed to increase temperatures of the exhaust system and remove harmful emissions as they are passed through.
Muffler – The muffler does exactly what it suggests, muffles the noise of the engine. There are many different designs of mufflers which are suitable for different applications.
Oxygen Sensor – The Oxygen Sensor is a small sensor mounted into the exhaust system which is designed to determine whether the engine is running lean or rich. In most Exhaust Systems there are a minimum of 2 Oxygen Sensors, One located before the Catalytic Convertor and one located after.
Exhaust Piping – The Exhaust Piping is what joins all of these other crucial parts to one another and transfers the Exhaust Gases from the engine to the rear of the vehicle.
Design principles of an Exhaust System
Exhaust systems are designed to carry toxic and harmful gasses in the form of hydrocarbons, nitrogen oxides and carbon monoxide away from the front of the vehicle and the operator towards the rear of the vehicle. With advanced technology it’s particularly important to have a tuned exhaust system that not only allows limited restriction for the gases to escape but enough restriction to reduce noise to be comfortable while driving.
Explanation of Exhaust Components and how they work
Headers and manifolds are the first section of the exhaust system after the gases exit the engine head. In general production engines the exhaust manifold is a cast iron piece that is a cost effective unit to produce, in performance styled motors you will find mild steel tubing that is welded in “tuned lengths” between cylinder to add to performance, the principle here is as one cylinder fires there is a minor vacuum created until the next firing cycle, joining a second cylinder firing at 180degree intervals fills that vacuum and assists the even flow of gasses out of the pipes. Clearly there is a lot of research involved in design and length of header/extractor pipes.
A catalytic convertors primary function is to reduce air pollution by converting toxic gasses by catalysing a redox reaction (oxidation or reduction) into an acceptable form of less toxic gas. This happens by combining oxygen and carbon monoxide and unburned hydrocarbons to produce carbon dioxide (co2) and water (h2o), in conjunction with this they assist in reducing oxides of nitrogen (nox). The placement of the catalytic convertor directly behind the exhaust manifold allows the hotter gasses close to the engine to be more effectively dealt with as opposed to further along the exhaust system.
Muffler and resonator
A muffler and resonators primary function is to reduce noise. This can be achieved by a number of ways but the two most significant methods is to create chambers with internal piping running in opposite directions into two separate chambers allowing or forcing the rate of exhaust gas flow to change, this rapid change of flow “muffles “ the noise. Alternatively the muffler pipe can be straight through but with multiple holes, up to a thousand small holes and traditionally surrounded outside the pipe with a fibreglass insulation that allows the gasses to expand and contract therefore interfering with the harmonics and reducing the noise level.
A tail pipes primary function is to exit the exhaust into the atmosphere as far away as possible from the driver and vehicle occupants as possible. The rear of the vehicle is the most common position for this ensuring that no gasses are able to recirculate back into the inside of the vehicle.