Car Exhaust System
Car exhausts carry the poisonous combustion gases produced when the fuel and air are burned in the engine cylinders away from the driver and passengers to vent the gases away from where they are likely to enter the vehicle. An added benefit of this funnelling process is the dramatic reduction in engine noise. Exhaust failure is most noticeable by the blowing noise noticeable when the exhaust corrodes and forms a hole in the tube or baffle wall.
The Car Exhaust is comprised of a series of sections that are bolted or welded together. The exhaust parts include:-
Exhaust manifold
The exhaust manifold fits to the cylinder head and comprises a set of dedicated pipes; one for each cylinder. The manifold cylinder pipes normally converge into one pipe. The exhaust manifold system is often made from cast iron although aluminium, steel, or stainless steel can be used.
Header - Performance Enhancing Manifold Design
The header is a form of manifold that allows the engine to expel spent exhaust gases out of the cylinders. The header enhances performance by removing or significantly reducing exhaust back-pressure. This frees up the piston to transfer all its available energy into rotational force to increase the effective engine power.
The exhaust header aims to eliminate back pressure in the manifold by giving each cylinder its own exhaust pipe. The pipes are designed to give an identical exhaust gas path into a common collector to eliminate or greatly reduce back pressure.
Oxygen sensor
Every modern car built around a fuel injected engine has an oxygen or Lambda sensor to measure how much oxygen is present in the exhaust. A computer uses information from the sensor to adjust the amount of fuel injected.
Catalytic Converter
The catalyst in the converter forms a reactive surface where the carbon monoxide and unburnt or partially combusted hydrocarbons are converted into carbon dioxide and water. It relies upon the heat from the engine to optimise its catalytic efficiency.
Back Box or Muffler
The backbox does most of the noise reduction. It contains a deceptively simple system of baffles that bounce the sound waves from the combustion explosions of the engine. As the sound waves bounce back and forth they interfere and mostly cancel out. Some boxes are packed with fiberglass or other sound deadening packing.
Exhaust pipe:
The tubing connecting the exhaust sections together is known as the exhaust pipe and is uniquely shaped to fit each make and model of car.
Tailpipe
Fitting a larger tailpipe produces the characteristic big-bore sound, as the sound exiting the pipe is richer in low-frequency sound waves.
Exhaust Fittings
The exhaust uses a series of gaskets compressed between the connective flanges to clamp or bolt the exhaust sections together.
The exhaust is normally suspended on a series of rubber hangers that allow the exhaust to flex and reduce vibration and noise transfer into the cabin.