Exhaust System Exhaust system components n n 1

Exhaust System

Exhaust system components: n n 1 -Catalytic Converter 2 -Muffler 3 -Resonator 4 -Tail pipe

Catalytic converter n n Came about in 1975. It converts harmfull pollutants into less harmful emissions.

The main emissions of acar engine 1 -Nitrogen gas (N 2 ) Air is 78 -percent nitrogen gas. 2 - Carbon dioxide (CO 2) This is aproduct of combustion, the carbon in the fuel bonds with the oxygen in the air. 3 -Water vapor ( H 2 O) This id aproduct of combustion , the hydrogen in the fuel bonds with the oxgen in the air. n

Catalytic converter are designed to reduce all three 1 - carbon monoxide (co) Is apoisonous gas that is colorless and odorless. n 2 - Hydrocarbons or volatile organic compounds (Vocs) Are major component of smog. n 3 - Nitrogen oxides (NO and NO 2 called Nox) Are a contributor to smog and acid rain. n

Catalytic converter structure There are two different types of catalyst at work 1 - a reduction catalyst. 2 - and an oxidation catalyst. Both types of aceramic structure coated with a metal catalyst , usually platinum , rhodium and or palladium.

How catalytic converter work A- The Reduction catalyst. Is the first stage of the catalytic converter , it usesplatinum and rhodium to help reduce the nox emission. n B-The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide. n C- Control system (O 2 sensor ) that monitors the exhaust stream, and uses this information to control the fuel injection system. n

The catalytic converter works efficiently at afairly high temperature We can reach this By : n 1 - move the catalytic converter closer to the engine. n 2 - preheating the catalytic converter.

Catalytic converter in diesel engines Do not work as well in reducing Nox.

2 - Muffler n Cancel out most of an engine’s noise. (sound wave).

Where Does the sound come from ? n Pulses are created when an exhaust valve opens and a burst of high – pressure gas suddenly enters the exhaust system.

? How can you cancel out sounds If the first wave is at its maximum pressure , the second wave is at its minimum. If both of these waves hit your ear drum , you wouldnot hear anything. n

Inside a Muffler

Resonator

: Common problems n n n 1 - corrosion… or more commonly known as Rust 2 - short trips. 3 - oxygen sensor wearing. 4 -The rust in the muffler. 5 - the catalytic converter will become clogged.

References : n n http: //auto. howstuffworks. com/turbo. htm http: //auto. howstuffworks. com/muffler. htm