There are three main types of vehicle emissions: exhaust, evaporative, and crankcase. Exhaust emissions are produced during fuel combustion and include carbon monoxide, nitrogen oxides, and hydrocarbons. Evaporative emissions occur when gasoline vapors escape into the air through fuel evaporation processes like refueling, engine heating, and the hot soak period after the vehicle is turned off. Crankcase emissions leak from the gap between the cylinder and piston ring and contain blowby gases mixed with oil. Devices to control emissions include catalytic converters, which convert toxic gases into harmless gases, exhaust gas recirculation systems, which lower combustion temperatures to reduce nitrogen oxide formation, and positive crankcase ventilation systems.

1. 1 Written By: AMIR HASSAN
AUTO – MOBILE EMISSION CONTROL.
There are three different types of auto
1) Exhaust – Emission : due to combustion of fuel
 Produce’s CO, CO2, NOX
2) Evaporative – Emission:
emissions occur through several ways.
 Refueling: gasoline vapors are always present in fuel tanks. These vapors are forced out
when the tank is filled with liquid fuel.
 Running Losses: The hot engine & exhaust system can vaporize gasoline when the car is
running.
 Hot Soak: The engine remains
are continues.
2) Crankcase– Emission: Leakage of combustion gases to engine occur due to gap between
cylinder and piston ring produced gases which contain liquid oil called blowby gases.
AUTO – MOBILE EMISSION CONTROL DEVICES.
The Following devices are used to control
 Catalytic Converters.
 Exhaust Gases Recirculation (EGR) System.
 Positive Crankcase Ventilation (PCV) System.
 Fuel Evaporative Emission Control (EVAP) System.
AMIR HASSAN | Of Chemistry Department GPGC – MARDAN.
MOBILE EMISSION CONTROL.
There are three different types of auto – mobile emission occur which are :
due to combustion of fuel
X, and Hydrocarbons.
: HC’s escape into air through fuel evaporation. Evaporation
emissions occur through several ways.
: gasoline vapors are always present in fuel tanks. These vapors are forced out
when the tank is filled with liquid fuel.
: The hot engine & exhaust system can vaporize gasoline when the car is
engine remains hot for a period when car is parked & gasoline emission
Leakage of combustion gases to engine occur due to gap between
cylinder and piston ring produced gases which contain liquid oil called blowby gases.
MOBILE EMISSION CONTROL DEVICES.
The Following devices are used to control the auto – mobile emission
Catalytic Converters.
Exhaust Gases Recirculation (EGR) System.
Positive Crankcase Ventilation (PCV) System.
Fuel Evaporative Emission Control (EVAP) System.
HC’s escape into air through fuel evaporation. Evaporation
: gasoline vapors are always present in fuel tanks. These vapors are forced out
: The hot engine & exhaust system can vaporize gasoline when the car is
hot for a period when car is parked & gasoline emission
Leakage of combustion gases to engine occur due to gap between
cylinder and piston ring produced gases which contain liquid oil called blowby gases.
MOBILE EMISSION CONTROL DEVICES.

2. 2 Written By: AMIR HASSAN
1) Catalytic Converter :
 It’s a device used to reduce the
combustion engine.
 A catalytic converter is placed inside the tail pipe through which deadly exhaust
gases containing unburnt fuel, CO, NOX, are emitted.
 The function of catalytic converter is to convert these
(such as CO2, N2, O2) and water.
Types Of Catalytic Converters:
AMIR HASSAN | Of Chemistry Department GPGC – MARDAN.
Catalytic Converter :
It’s a device used to reduce the toxicity of gases emission occur from internal
converter is placed inside the tail pipe through which deadly exhaust
gases containing unburnt fuel, CO, NOX, are emitted.
The function of catalytic converter is to convert these gases into harmless gases
and water.
Types Of Catalytic Converters:
toxicity of gases emission occur from internal
converter is placed inside the tail pipe through which deadly exhaust
gases into harmless gases

3. 3 Written By: AMIR HASSAN
2) Exhaust Gases Recirculation (EGR) System.
 The Exhaust Gas Recirculation (EGR) system's purpose is to
contribute to air pollution.
 This keeps combustion temperatures below 1500 degrees
the reaction between nitrogen and oxygen that forms NOx.
 Exhaust gas recirculation reduces the formation of NO
exhaust gas to "leak" into the intake manifold.
3) Positive Crankcase Ventilation (PCV) System.
AMIR HASSAN | Of Chemistry Department GPGC – MARDAN.
Exhaust Gases Recirculation (EGR) System.
The Exhaust Gas Recirculation (EGR) system's purpose is to reduce NOx emissions that
contribute to air pollution.
This keeps combustion temperatures below 1500 degrees 0
C (2800 degrees F) to reduce
the reaction between nitrogen and oxygen that forms NOx.
Exhaust gas recirculation reduces the formation of NOX by allowing a small amount of
exhaust gas to "leak" into the intake manifold.
Positive Crankcase Ventilation (PCV) System.
reduce NOx emissions that
C (2800 degrees F) to reduce
lowing a small amount of

4. 4 Written By: AMIR HASSAN | Of Chemistry Department GPGC – MARDAN.
1) Fuel Evaporative Emission Control (EVAP) System.
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