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

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). Next >

Emission Types Carbon Monoxide (CO) is invisible poisonous gas. Particulates are soot particles from fuel additives. Next >

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

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. Next >

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). Next >

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

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. Next >

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

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) Next >

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

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). Next >

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

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 Next >

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 Next >

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

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. Next >

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

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 Next >

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

Summary You should now be aware of: Types of Emissions Emission Control Devices End >