Emissions Systems
What % comes from fuel evaporation?
20%
What % comes from the crankcase vapors?
20%
Monolithic converter
Ceramic honeycomb catalyst
Catalyst monitor
Checks the oxygen content of the exhaust gases after eating the catalytic converter to determine if the catalyst elements are working
Dual Bed
Contains 2 separate catalyst units enclosed in a single housing
Purge valve
Controls the flow of vapors from the canister to the intake manifold
Enhanced EVAP system has several components and features not found on what?
Conventional EVAP systems
EGR Monitoring
Cools down, lowers NOX
Non-vented fuel tank cap
Prevents fuel vapors from entering the atmosphere through the tanks filler neck
Actuator Monitoring
Proper amount of current
2 way catalytic converter
Reduce 2 types of exhaust emissions (HC & CO) and coated with platinum
Air injection system
Reduces hydrocarbons and carbon monoxide and forces fresh air into the exhaust ports or catalytic converter to reduce (burn off) HC and CO
Pellet catalytic converter
Small ceramic beads are used
Particulates
Solid particles of carbon soot and fuel additives that blow out the vehicles tailpipe
Liquid vapor separator
Sometimes used to keep fuel from entering the evap emissions system
Charcoal canister
Stores fuel vapors when the engine is not running and usually around the fuel tank
Closed PCV
System that is always sealed uses a sealed oil filler cap
Thermastatic air cleaner system
TAC system help speed engine warmup and keeps air entering the engine warm
Catalyst Monitor
Works with both O2 sensors and checks the oxygen content of the exhaust gases engine misfire monitoring
Photochemical smog
Yellow-gray cloud of pollution after sunlight hits it
3 way reducing
all 3 types
EVAP Monitoring
Prevents HC
Evaporative emissions control system (EVAP)
1. Air cleaner carbon element 2. Prevents toxic fuel system vapors from entering the atmosphere
What are some engine modifications to reduce emissions?
1. Lower compression ratios 2. Smaller combustion chamber surface volume 3. Reduce quench areas in the combustion chambers 4. Higher operating temperature 5. Leaner air-fuel mixtures 6. Wider spark plug gaps
Emissions system purpose?
1. Reduces the amount of chemicals released into the atmosphere 2.Helps keep the air clean
What % comes from engine exhaust?
60%
Exhaust gas recirculation (EGR) system
Allows burnt exhaust gases to enter the engine intake manifold to help reduce NOX emissions
Air pollution is caused by what?
An excess amount of chemicals in the air
Catalyst
Any substance that speeds a chemical reaction without itself being changed
Blowby gases
Caused by pressure leakage past the piston rings on the power stroke.
Oil-air separator
Device that makes oil vapors condense and flow back into the oil pan
Oxides of Nitrogen (NOX)
High combustion temperature (2500F) *dirty color*
OBD II
Monitors major emissions control system and ECM sets trouble code and illuminates malfunction indicator light when problems are detected
Oxygen sensor
Monitors the exhaust gases for oxygen content and measure O2 in the exhaust
What is in the place of the PCV valve?
Oil-air separator
Catalytic Converter
Oxides (burns) the remaining HC and CO emissions that pass into the exhaust system
Carbon Monoxide (CO)
Partially burned fuel
Hydrocarbons (HC)
Unburned fuel vapors into the atmosphere
PCV valve
Used to control the flow of air through the PCV system
Rollover valve
Used to vent line from the fuel tank. Keeps liquid fuel from entering the vent line in case the vehicle rolls over during an auto accident
PCV
Uses engine vacuum to draw blowby gases into the intake manifold for reburning in the combustion chambers
Computerized emission control system
Uses various engine sensors a 3 way catalytic converter, an ECM, electronic fuel injection to reduce pollution levels from the vehicle
