Engine Emissions and Air Pollution Notes | EduRev

: Engine Emissions and Air Pollution Notes | EduRev

 Page 1


Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_1.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Engine Emissions and Air Pollution
The Lecture Contains:
Principal Engine Emissions
Sources of Engine/Vehicle Emissions
Emissions and Pollutants
Photochemical Smog
Photochemical Reactivity of Hydrocarbons
Health Effects of Air Pollutants
Historical Overview: Engine and Vehicle Emission Control
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 2


Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_1.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Engine Emissions and Air Pollution
The Lecture Contains:
Principal Engine Emissions
Sources of Engine/Vehicle Emissions
Emissions and Pollutants
Photochemical Smog
Photochemical Reactivity of Hydrocarbons
Health Effects of Air Pollutants
Historical Overview: Engine and Vehicle Emission Control
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Principal Engine Emissions
SI Engines CO, HC and NOx
CI Engines CO, HC, NOx and PM
CO = Carbon monoxide, HC = Unburned hydrocarbons, NO
x
 = Nitrogen oxides mainly  mixture of NO and
NO
2 
 , 
PM = Particulate matter
Other engine emissions include aldehydes such as formaldehyde and acetaldehyde primarily from the alcohol
fuelled engines, benzene and polyaromatic hydrocarbons (PAH).
Sources of Engine/Vehicle Emissions
Figure 1.3 shows the sources of emissions from a gasoline fuelled SI engine viz., exhaust, crankcase blow by
and fuel evaporation from fuel tank and fuel system
 
Figure. 1.3
Emission sources in a gasoline
fuelled car
From a diesel engine powered vehicle the emission sources are shown in Fig. 1.4.
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 3


Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_1.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Engine Emissions and Air Pollution
The Lecture Contains:
Principal Engine Emissions
Sources of Engine/Vehicle Emissions
Emissions and Pollutants
Photochemical Smog
Photochemical Reactivity of Hydrocarbons
Health Effects of Air Pollutants
Historical Overview: Engine and Vehicle Emission Control
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Principal Engine Emissions
SI Engines CO, HC and NOx
CI Engines CO, HC, NOx and PM
CO = Carbon monoxide, HC = Unburned hydrocarbons, NO
x
 = Nitrogen oxides mainly  mixture of NO and
NO
2 
 , 
PM = Particulate matter
Other engine emissions include aldehydes such as formaldehyde and acetaldehyde primarily from the alcohol
fuelled engines, benzene and polyaromatic hydrocarbons (PAH).
Sources of Engine/Vehicle Emissions
Figure 1.3 shows the sources of emissions from a gasoline fuelled SI engine viz., exhaust, crankcase blow by
and fuel evaporation from fuel tank and fuel system
 
Figure. 1.3
Emission sources in a gasoline
fuelled car
From a diesel engine powered vehicle the emission sources are shown in Fig. 1.4.
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
Figure 1.4
Emission sources in a diesel engine powered
bus.
 
Page 4


Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_1.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Engine Emissions and Air Pollution
The Lecture Contains:
Principal Engine Emissions
Sources of Engine/Vehicle Emissions
Emissions and Pollutants
Photochemical Smog
Photochemical Reactivity of Hydrocarbons
Health Effects of Air Pollutants
Historical Overview: Engine and Vehicle Emission Control
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Principal Engine Emissions
SI Engines CO, HC and NOx
CI Engines CO, HC, NOx and PM
CO = Carbon monoxide, HC = Unburned hydrocarbons, NO
x
 = Nitrogen oxides mainly  mixture of NO and
NO
2 
 , 
PM = Particulate matter
Other engine emissions include aldehydes such as formaldehyde and acetaldehyde primarily from the alcohol
fuelled engines, benzene and polyaromatic hydrocarbons (PAH).
Sources of Engine/Vehicle Emissions
Figure 1.3 shows the sources of emissions from a gasoline fuelled SI engine viz., exhaust, crankcase blow by
and fuel evaporation from fuel tank and fuel system
 
Figure. 1.3
Emission sources in a gasoline
fuelled car
From a diesel engine powered vehicle the emission sources are shown in Fig. 1.4.
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
Figure 1.4
Emission sources in a diesel engine powered
bus.
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_3.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Emissions and Pollutants
Engine emissions undergo chemical reactions in atmosphere known largely as ‘photochemical’ reactions
and give rise to other chemical species which are hazardous to health and environment. Linkage of
engine emissions and air pollutants is shown in Fig. 1.5.
 
 
TSP = Total suspended particulate matter in air
PAN = Peroxy- acetyl nitrate
Figure. 1.5 
Air pollutants resulting from engine
emissions
 
Photochemical Smog
Photochemical smog is a brownish-gray haze resulting from the reactions caused by solar ultraviolet
radiations between hydrocarbons and oxides of nitrogen in the atmosphere. The air pollutants such as
ozone, nitric acid, organic compounds like peroxy- acetylnitrates or PAN ( CH
3
CO-OO-NO
2
) are
trapped near the ground by temperature inversion experienced especially during winter months. These
chemical substances can effect human health and cause damage to plants. The photochemical reactions
are initiated by nitrogen oxides emitted by vehicles into atmosphere. A simple set of reactions leading to
photochemical smog formation is as follows:
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 5


Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_1.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Engine Emissions and Air Pollution
The Lecture Contains:
Principal Engine Emissions
Sources of Engine/Vehicle Emissions
Emissions and Pollutants
Photochemical Smog
Photochemical Reactivity of Hydrocarbons
Health Effects of Air Pollutants
Historical Overview: Engine and Vehicle Emission Control
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Principal Engine Emissions
SI Engines CO, HC and NOx
CI Engines CO, HC, NOx and PM
CO = Carbon monoxide, HC = Unburned hydrocarbons, NO
x
 = Nitrogen oxides mainly  mixture of NO and
NO
2 
 , 
PM = Particulate matter
Other engine emissions include aldehydes such as formaldehyde and acetaldehyde primarily from the alcohol
fuelled engines, benzene and polyaromatic hydrocarbons (PAH).
Sources of Engine/Vehicle Emissions
Figure 1.3 shows the sources of emissions from a gasoline fuelled SI engine viz., exhaust, crankcase blow by
and fuel evaporation from fuel tank and fuel system
 
Figure. 1.3
Emission sources in a gasoline
fuelled car
From a diesel engine powered vehicle the emission sources are shown in Fig. 1.4.
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_2.htm[6/15/2012 2:55:11 PM]
Figure 1.4
Emission sources in a diesel engine powered
bus.
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_3.htm[6/15/2012 2:55:11 PM]
 Module 1: An Overview of Engine Emissions and Air Pollution
 Lecture 2: Engine Emissions and Air Pollution
 
Emissions and Pollutants
Engine emissions undergo chemical reactions in atmosphere known largely as ‘photochemical’ reactions
and give rise to other chemical species which are hazardous to health and environment. Linkage of
engine emissions and air pollutants is shown in Fig. 1.5.
 
 
TSP = Total suspended particulate matter in air
PAN = Peroxy- acetyl nitrate
Figure. 1.5 
Air pollutants resulting from engine
emissions
 
Photochemical Smog
Photochemical smog is a brownish-gray haze resulting from the reactions caused by solar ultraviolet
radiations between hydrocarbons and oxides of nitrogen in the atmosphere. The air pollutants such as
ozone, nitric acid, organic compounds like peroxy- acetylnitrates or PAN ( CH
3
CO-OO-NO
2
) are
trapped near the ground by temperature inversion experienced especially during winter months. These
chemical substances can effect human health and cause damage to plants. The photochemical reactions
are initiated by nitrogen oxides emitted by vehicles into atmosphere. A simple set of reactions leading to
photochemical smog formation is as follows:
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...nts%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture2/2_3.htm[6/15/2012 2:55:11 PM]
 
 
 is energy of a photon and UV is ultraviolet light radiations .
 
 
 
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