Automobile emission control systems

Automobile Emission Control Systems

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who is the Most Beneficial &
Most Merciful. ”

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Automobile Emission
Control Systems
USPCASW MUET Jamshoro
Presented by:
IHSAN ALI WASSAN
MS(Environmental Engineering)
U.S -Pakistan Center for Advanced Studies in Water
Mehran University of Engineering and Technology, Jamshoro

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Mobile sources of Air Pollution and their broad classification
Types of auto emissions
Air Pollution reasons
Emission control systems
Laws and regulatory standards
Policies and Programs for the Management of Air Quality in Pakistan
Conclusion
References
Outlines

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Mobile sources of Air Pollution
Mobile source air pollutionincludes anyair pollutionemitted by
-motor vehicles,
-airplanes,
-locomotives, and
-otherengines
Google (source)

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Broad Classification
Road sources
Cars
Light Duty & Heavy Duty Trucks
Buses
Motorbikes
Non-road sources
Aircraft
Motorboats(Diesel & Gasoline)
Locomotives
Construction Equipment
Diesel exhaust –Wikipedia (source)
Car emissions and global warming –union of concerned scientists (source, Google)
Google (source)

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Types of Auto Emissions
Evaporative Emissions (From Carburetor, Crankcase blow-by)
Refueling Losses( from Fuel tank )
Exhaust Emissions
Carbon Dioxide (CO2)
Nitrogen Oxides (NOx)
Carbon Monoxide (CO)
Aldehydye and other emissions (H2S and SO2 gases, Ash dust, H2SO4)
Smoke and particulate (White , Black smoke)
Theoretical combustion
Incomplete combustion of fuel
by liquid droplets of lubricating oil and fueloil
Incomplete combustion of fuel

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Source: EEA Report -Exploring road transport emissions -a non technical guide
(2016)
Types of Auto Emissions

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Source: BEIS/ Defra Greenhouse Gas Conversion factors 2019 (BBC)

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To prevent unnecessary damage to human health and
the environment, environmental regulatory agencies
such as theU.S. Environmental Protection Agencyhave
established policies to minimize air pollution from
mobile sources
Mobile sources of Air Pollution

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Air Pollution Reasons
Incomplete combustion of carbonaceous fuel
Evaporation Loss
Exhaust Emission
Low Quality Fuel

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Elements of a comprehensive vehicle
pollution control strategy
Traffic &
Demand
Management
Clean Fuels
Appropriate
Maintenance
Zero
Emission
Vehicles
Clean
Vehicle
Technology

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Emission control systems
Modern vehicles are fitted with emission control systems,
designed to reduce emissions. These include:
Catalytic Converter
Air injection (AIR) system
Exhaust gas recirculation (EGR) system
Evaporative emissions control (EVAP) system
Positive crankcase ventilation (PCV) system

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https://www.alamy.com/stock-photo-fuel-exhaust-and-emission-control-systems-25485645.html

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A catalytic converter removes the harmful gases that exit the tailpipe
A three-way converter contains honeycombcoated with platinum, rhodium
and palladiumto form oxidization and reduction converters
Pt and Rh (reduction catalysts, pull of nitrogen and oxygen)
Pt and pd (oxidation catalysts, use oxygen, help to bind them with CO to get
CO2, also oxidize any unburned HC)
Catalytic Converter
The oxidization converter stores oxygen when the
air/fuel mixture islean (when AFRis higher than the
stoichiometric ratios)

15. Catalytic Converter
The conversion process produces temperatures upto 1600°F
Rhodiumis best Catalyst to control NOx keeping A/F ratio within 14.6:1 to14.7:1
Catalyst honeycomb
Outlet
Oxidization converter
Reduction converterSteel shell
Inlet

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Air Injection System
•Clean air into exhaust ports by
a vane type air pump to ignite
unburned fuel (hydrocarbons),
within the exhaust manifold
•Vacuum operated diverter valve is used to
stop air flow during deceleration, otherwise
backfiring may occur
•A check valve is placed in the line to stop
hot exhaust gasestraveling back up the air
hose
Figure . https://www.pistonheads.com

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•The EGR system reduces NOX emissions
•It feeds inert exhaust gases back into the intake manifold, where they dilute the
air/fuel mixture, without altering the air/fuel ratio. With less oxygen and fuel,
combustion temperatures (and therefore NOx levels) are lower.
•The system uses an EGR valve that can be either vacuum and/or electronically
controlled.
•Early EGR valves were operated by ported vacuum. They did not function until
engine was at operating temperature and above idle speed.
Exhaust Gas Recirculation (EGR) System

18. Exhaust Gas Recirculation (EGR) System
Throttle plate
TVV
Exhausted gas flow
Fresh Air flow
EGR valve
Air filter
Figure Principle of Exhaust Gas Re-circulation (EGR) (Source: YouTube)
Electro-pneumatic
pressure transformer

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•Fuel produces vapors, if stored in a container, the fuel tank has a sealed cap
that may contain valves to relieve fuel pressure and allow air in
•The tank contains an air dome that allows for fuel expansion and a vent line
for vapor removal
•It connects to a charcoal canisterthat stores vapors when the engine is
switched off
•A purge valve is used to control vapor removal from the canister
•Vapors are drawn into the intake manifold via a purge line
•In modern engines, the ECU controls valve (Engine control unit) operation
for optimum engine efficiency
Evaporative emissions control (EVAP) system

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Evaporative emissions control (EVAP) system
Fuel tank
Charcoal canister
Purge line
Purge valve
Intake manifold
Throttle plate
Vacuum line
Roll over/vapor separator
Vent line
Air
Fuel vapor
Vacuum
Non-vented cap

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•Combustion produces high pressure in a cylinder
•Some of the pressurized gas leaks past the piston rings into the crankcase,
even on a new engine and is known as 'blowby‘
•Older vehicles had a breather tube that vented these gases into the
atmosphere
•Modern vehicles are fitted with a PCV system
•Vacuumis used to suck blowby out of the crankcase and into the intake
manifold to be burned
•Fresh air replaces the gases in the crankcase
•System operation is regulated by a PCV valve
Positive Crankshaft Ventilation (PCV)

22. Air flow
Blowby
Fresh air mixes with blowby gases in the crankcase
Vapors pass
through the
PVC valve and
hose
Vapors pass
into the
intake
manifold
Fresh air enters
Positive Crankshaft Ventilation (PCV)

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https://www.youtube.com/watch?v=JotiMO3R8bQ
Positive Crankshaft Ventilation (PCV)
(Working)

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PCV Valve
https://www.youtube.com/watch?v=JotiMO3R8bQ

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•The PCV valve is a spring-loaded device, with an engine specific orifice size
•The valve is sealed shut when an engine is stopped to prevent backfires
•At engine idle speed, maximum vacuum defeats spring pressure and the
plunger moves to the other end of the valve, allowing minimal vapor flow
•At normal engine speeds, lower vacuum levels allow the plunger to move to
a central position and maximum vapor flow occurs
PCV Valve

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PCV Valve
To manifold
Valve
Seal seat
From crankcase
Vapor Spring

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First federal air pollutionlegislation
Funded research for scope and sources of air pollution
Authorized the development of a national program to
address air pollution related environmental problems &
techniques to minimize air pollution
Laws and regulatory standards
Clear Air Act (1963)
Air Pollution Control Act (1955)

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Motor Vehicle Air Pollution Control Act (1965)
The first federal legislation designed to control emissions from
automobiles
The act required a 72% reduction inhydrocarbonemissions, a 56%
reduction incarbon monoxideemissions, and a complete elimination
ofcrankcasehydrocarbon emissions for all light duty vehicles
produced after 1968, using a 1963 base year.
Laws and regulatory standards

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Air Quality Act (1967)
Authorized enforcement procedures for air pollution problems
involving interstate transport of pollutants and expanded research
activities
Authorized the establishment of National Ambient Air Quality
Standards and requirements for control of motor vehicle emissions
Clean Air Act Extension (1970)
Laws and regulatory standards

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Clean Air Act Amendments (1977)
Laws and regulatory standards
Authorized provisions related to the Prevention of Significant
Deterioration
Authorized programs for Acid Deposition Control, to control 189 toxic
pollutants, including those previously regulated by theNational
Emissions Standards for Hazardous Air Pollutants
Clean Air Act Amendments (1999)

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•Total emissions by the transport sector was estimated in 1998 by the National
Emissions Inventory of Pakistan in the “Male Declaration on Control and
Prevention of Air Pollution and it's likely Trans boundary Effects for South
Asia” at
•324,473 tons of NOx (over 90% by diesel, 9.5 %by gasoline; 65% share of
total NOx emissions by all sectors)
•35,362 tons of PM (93% diesel, 6.5% by gasoline; 6%share of total emissions)
•120,871 tons of SO2 (99% by diesel; 16% share of total SO2 emissions)
Policies and Programs for the Management of Air
Quality in Pakistan

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Policies and Programs for the Management of Air
Quality in Pakistan
www.environment.gov.pk

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Policies and Programs for the Management of Air
Quality in Pakistan
However, motor vehicle examiners who operate within the transport departments in
each province conduct arbitrary inspections and issue a certificate of fitness for public
and commercial vehicles
EPAs and the provincial traffic police are implementing a provincial motor vehicle
ordinance that allows them to apprehend private and public transport vehicles emitting
visible smoke, vapour, grit, sparks, ashes, cindersor oily substances and fine them Rs.
500 for such violation (ADB, CAI ASIA and Pakistan Clean Air Network 2006)

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Pakistan: Vehicle Registration Trends
1994 -2005

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References
•The selection of an appropriate engine
•A European Union-funded project, called “NICE” or New
integrated combustion system for future passenger car engines,
aiming to develop a new integrated combustion system
Conclusion

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References
•Atmospheric ecosystem, chapter 5, Source: Adapted from Pakistan EPA, Pakistan Clean Air Program
(2006); Pakistan EPA/World Bank (2006).
•Source: EEA Report -Exploring road transport emissions -a non technical guide (2016)
•BEIS/ Defra Greenhouse Gas Conversion factors 2019 (BBC)
•http://www.environment.gov.pk/images/environmentalissues/EstablishmentMotorvehicleemissionsInsp
ectionsystem.pdf
•https://www.youtube.com/watch?v=JotiMO3R8bQ
•https://slideplayer.com/slide/6167168/