1. Emission Control Topics covered in this presentation:
Types of Emissions
Emission Control Devices
ClassAct SRS enabled.

2. Emission Types Vehicles produce harmful emissions.
Hydrocarbons (HC) are unburnt fuel entering atmosphere.
Oxides of Nitrogen (NOX) are nitrogen mixed with oxygen at high pressure and temperature 1400°C (2500°F).
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3. Emission Types Carbon Monoxide (CO) is invisible poisonous gas.
Particulates are soot particles from fuel additives.
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4. Question 1
Which of the following is NOT a major component of harmful exhaust emissions?
A) Soot particles
B) Unburnt fuel
C) Oxides of Nitrogen
Correct Answer = D
D) Carbon Dioxide

5. Emission Control Systems
Modern vehicles are fitted with systems to reduce emissions, including:
A catalytic converter.
Air injection system.
Exhaust gas recirculation (EGR) system.
Evaporative emissions control (EVAP) system.
Positive crankcase ventilation (PCV) system.
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6. Oxidization converter
Catalytic Converter
Removes harmful gases that exit exhaust.
Contains honeycomb coated with platinum and palladium (oxidation converter) and rhodium (reduction converter).
Oxidization converter changes HC and CO into H2O and CO2 (carbon dioxide).
Catalyst honeycomb
Reduction converter
Oxidization converter
Reduction converter changes NOX into N2 (nitrogen) and O2. (oxygen).
Steel shell
Inlet
Outlet
Conversion temperatures up to 900°C (1600°F).
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7. Question 2 What is the common name for this chemical?
A) Di-hydrogen oxide
B) Water
C) Carbon dioxide
Correct Answer = B
D) Oxygen hydroxide

8. Air Injection System
Forces air into exhaust ports to burn excess hydrocarbons.
Diverter valve
to air injection hose
Air injection manifold
Check valve
Air pump to diverter valve hose
Vacuum source and line
Air pump
Air pump provides a supply of pressurized air, via air injection manifold.
Diverter valve stops air flow under deceleration.
Check valve stops hot exhaust gases coming back up air hose.
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9. Question 3
Which part stops hot exhaust gases coming back up the air hoses?
A) Air pump
B) Diverter valve
C) Check valve
Correct Answer = C
D) Vacuum line

10. Temperature switch (TVV)
Exhaust Gas Recirculation (EGR) System
Reduces NOX by feeding inert exhaust gases into inlet manifold, therefore lowering combustion temperature.
EGR valve can be vacuum and/or electronically controlled.
Early EGR valves operated by ported vacuum.
Exhaust gas
Inlet
manifold
EGR valve
Throttle valve
Vacuum
Temperature switch (TVV)
Ported vacuum
Exhaust gas flow
(Closed)
(Open)
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11. Question 4
What is the main cause of oxides of nitrogen being produced in a vehicle exhaust system?
A) High temperatures
B) Impure fuel
C) Additives in the fuel
Correct Answer = A
D) Too much pressure in the fuel pipe

12. Pressure voltage signals
Electronic EGR Components
ECU uses data from sensors to determine amount of EGR.
Metering
orifice
Exhaust gas
Inlet
manifold
Vacuum output
EVR duty cycle
control signal
Pressure voltage signals
EGR flow
Exhaust
pressure
Intake
vacuum
DPFE sensor
ECU
EVR
EGR valve
ECU operates electronic vacuum regulator (EVR) valve to control EGR valve.
Differential pressure feedback (DPFE) sensor provides feedback confirmation that EGR is operating (EOBD requirement).
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13. Question 5
How many intakes from the exhaust are there for a DPFE sensor in an EGR system?
Enter your answer and press SEND.
Correct Answer = 2

14. Electronic Evaporative Emissions Control
Fuel stored in a container (fuel tank) produces vapours.
Older vehicles had vented fuel system, allowing vapours into atmosphere.
Modern vehicles have sealed fuel system.
Fuel tank is fitted with sealed cap and air dome for fuel expansion.
High pressure
release cap
Air dome
Fuel outlet
Vent line
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15. Roll over valve/ vapour separator
Electronic Evaporative Emissions Control
Vent line connects to charcoal canister, via roll over/vapour separator valve.
Charcoal canister stores fuel vapours.
Purge valve controls vapour removal into inlet manifold, via purge line.
Purge valve operated by vacuum (shown) and/or ECU.
Vacuum
Fuel vapour
Air
Purge line
Fuel tank
Charcoal canister
Non-vented cap
Inlet manifold
Throttle valve
Roll over valve/ vapour separator
Purge valve
Vent line
Vacuum line
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16. Question 6
In an electronic evaporative emissions control system, where does the vapour end up being vented?
A) In the charcoal canister
B) Back into the fuel tank
C) In the inlet manifold
Correct Answer = C
D) In the exhaust manifold

17. Positive Crankshaft Ventilation (PCV)
Combustion gases leak past piston rings, into crankcase - blowby.
Fresh air enters through the air cleaner
Vapours pass into the inlet manifold
Air flow
Blowby
Fresh air mixes with blowby gases in the crankcase
PCV valve
Older vehicles vented gases into atmosphere.
Modern vehicles use a PCV system to remove gases to be burnt in the inlet manifold.
PCV system operation is regulated by a PCV valve.
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18. Question 7 Where does blowby occur? A) Past the piston rings
B) At the exhaust
C) In the inlet manifold
Correct Answer = A
D) At the air cleaner

19. PCV Valve Spring loaded valve that is shut when engine is off.
At idle, maximum vacuum defeats spring pressure and minimal crankcase vapours flow.
At normal engine speeds, plunger moves to a central position and maximum vapours flow.
Spring
To manifold
Valve
Seal seat
From crankcase
= Vapour
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20. Question 8
What is the position of the plunger when maximum vapour flows in a PCV valve?
A) Maximum in
B) Central
C) Maximum out
Correct Answer = B

21. Summary You should now be aware of: Types of Emissions
Emission Control Devices
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