Exhaust System

Exhaust systems reduce the amount of noise produced by the engine and channel the high-temperature, poisonous exhaust gases from the engine by safely routing them under the vehicle. Then, through a system of manifolds, pipes, and sound-absorbing mufflers, the gases are released out of the back of the vehicle.

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Emissions System

During normal vehicle operation, emissions are produced. While some of these emissions are harmless like water, heat, and oxygen, harmful byproducts—hydrocarbons (HCs), carbon monoxide (CO), and nitrogen oxide (NOx)—are also produced. One way the system reduces these harmful byproducts is by making the engine run more efficiently. The emissions system also recycles emissions back through the combustion process or converts them into harmless gases.

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Emissions System

During normal vehicle operation, emissions are produced. While some of these emissions are harmless like water, heat, and oxygen, harmful byproducts—hydrocarbons (HCs), carbon monoxide (CO), and nitrogen oxide (NOx)—are also produced. One way the system reduces these harmful byproducts is by making the engine run more efficiently. The emissions system also recycles emissions back through the combustion process or converts them into harmless gases.

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EVAP System

The evaporative control (EVAP) system captures any raw fuel evaporating from the fuel storage system. Under precise operating conditions dictated by engine temperature, speed, and load, the EVAP system purges these captured fuel vapors back into the combustion process.

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EGR System

The exhaust gas recirculation (EGR) system recycles a small amount of exhaust gas from the exhaust system and mixes it with the intake manifold air going into the combustion chambers. The addition of this inert (or non-combustible) exhaust gas limits the peak combustion temperatures to a point before the formation of nitrogen oxide (NOx) is known to occur.

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Secondary Air Injection System

Secondary air is used most commonly during the warmup cycle to help burn the rich air-to-fuel mixture needed to run a cold engine. Usually after two to three minutes, the catalytic converter is nearly at operational temperature, so the secondary air system shuts down. On some larger vehicles (e.g. trucks and SUVs), the secondary air system pumps air into exhaust manifolds during warmup and then directs the air into the catalytic converters during normal operation to help "burn off" the high fuel loads required to operate these heavy vehicles.

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