EmissionsAir is made up of :Fuel is primarily made up of :Perfect combustion =Imperfect combustionStoichiometricThink about itHC - HydrocarbonsCommon causes of high HCNot so common causes of HCCO - Carbon monoxideCauses of high COO2 - OxygenCO2 - Carbon dioxideNOx - Oxides of nitrogenCauses of high NOxSmog, what is it?State emissions testingIM240 testASM testWashington State testRemote sensing deviceEmission ControlsPCV systemsPurpose of PCVPCV historyComponents of PCVPCV system problemsPCV system diagnosis / testingInspect / replace at tune up intervalsEvaporative emissions systemEvap system purposeEvap system componentsSlide 34Evap system operation (purging)Slide 36Evap system problemsEarly fuel evaporation systemsEFE system purposeSlide 40Four types of EFET.A.C. componentsSlide 43T.A.C. problemsEFE grid componentsEFE grid operationEFE grid problemsCoolant passagesHeat riser valve purposeHeat riser valve componentsHeat riser problemsAir systems purposeTwo types - air pump and air suction (pulseair)Air pump systemAir pumpDiverter and gulp valvesCheck valveAir manifolds and pipesAir on CCC carsPulseair systemPulseair system problemsSlide 62EGR systemsPurpose : flows exhaust gas into intake to lower combustion temps which lowers NOxEGR detailsThree methods to obtain EGRControl of EGR needed for three reasonsEGR valve is a means of controlling EGR flowBackpressure TransducerElectronic controlsProblemsEGR testingSlide 73Catalytic convertersTwo types of convertersOxidizingMonolith construction (honeycomb)Pellet constructionOxidizing operationReducing catThree way or dual bedFirst part (bed) reducingSecond part oxidizing bedNeeds to be close to stoichiometric to workSlide 85Symptoms of plugging:Testing backpressureEfficiency lossSymptoms:DO NOT USE USED CATSOBDII efficiency monitorEfficiency testingSlide 93Using the bible sticker underhood to id componentsEmissionsAir is made up of :21%O278%N1% other gasses (mostly argon)Fuel is primarily made up of :HCPerfect combustion =HC, O2, N2 inHeat, H2O, CO2 and N2 outImperfect combustionAdds HC, CO, NOx and O2 to exhaustStoichiometricMuch of our emissions are related directly to A/F mixturesTheoretical best a/f ratio for emissions, economy, performance is 14.7:114.7 pounds of air to 1 pound of fuelThink about itGasoline weighs 6 pounds per gallonAir weighs 1 pound per 100 gallonsAt 15:1 it takes 9000 gallons of air to burn 1 gallon of fuel–9000 Gallons of air is equal to a single car garageHC - HydrocarbonsUnburned fuelCurrently measured in parts per million (ppm)Common causes of high HCMissfiring will cause HCs–Ignition –Mechanical –LeanA/f ratios off either wayTiming too advanced–Cools exhaust and cylinder wallsNot so common causes of HCQuench areas in combustion chamber–Carbon –Poor combustion chamber designCam profiles too aggressiveCO - Carbon monoxideCurrently measured in %EXTREMELY deadly gas!!!Partially burned fuelToo much fuel or too little O2–Combustion process ran out of airCO directly related to a/f ratiosCauses of high COHard to use as an A/F guide over 15:1 due to flattening out of curveMust use O2 above stoichiometricO2 - OxygenCurrently measured in %Unused air in exhaustO2 directly related to A/F Can also come from dilution–Air pump, exhaust leaksMisfires will raise O2If O2 is > 5% and vehicle running OK then it must be from dilutionCO2 - Carbon dioxideCurrently measured in %Byproduct of complete combustion Peak indicates good A/FAny problems pull CO2 away from peakUsed by Washington State to determine exhaust system integrityNOx - Oxides of nitrogenCreated when peak combustion temps. exceed 2500FCauses of high NOxAdvanced timing Inoperative EGRCarbon build upAnything that overheats combustion chamberSmog, what is it?Ground level ozone - O3Three ingredients; HC, NOx and sunlightCO is a pollutant all by itselfState emissions testingAttainment areas vs. non-attainment areas–Ozone and/or COCentralized vs. non-centralized testingIM240 testVarying load test with a constant volume samplerIdle testEvaporative emissions testTesting all three gasesVisual inspectionASM testLoaded test with constant load with a CVSIdle testWith or without an evaporative emissions testTest all three gassesWashington State testVariation of a ASM testLoaded cruise test except special vehiclesIdle test No NOx measuring in effect yetRemote sensing deviceLike photo radarUsed in CaliforniaEmission ControlsPCV systemsPurpose of PCV Control of blowbye gasses (HC)Reducing moisture and acids extending oil lifePCV historyRoad draft tube was responsible for 20-25% of vehicles emissionsCompletely sealed systems on all domestics since 1968Components of PCVBreather to filter incoming airPCV valve–Calibrated vacuum leak to intake manifold–Controls flow rates based on strength of vacuum–Eliminates backfiring path to crankcaseBleed orifice type / dual bleed typePCV system problemsCan flow up to 20% of the total a/f mixture at idlePlugged system could cause high CO at idleStuck open valve could cause lean or high idle speedPCV system diagnosis / testingValve should snap back at idle Rattle testCheap valves pass both tests but could flow wrongInspect breathers for pluggingOil dilution–1% Change = too much dilution or blowbyeInspect / replace at tune up intervalsEvaporative emissions systemEvap system purposeTo control HC during fuel evaporationEvap system componentsGas cap–Important seal of system–Easily over looked–Allows air in but pressure out only if >1 psiVapor liquid separatorEvap system componentsCanister–Stores evaporating vapors–Approx. 1.5 Lbs. Activated charcoal–Can hold twice it’s own weight in fuel–Chrysler used the crankcase in 1971Vapor line(s) from tank(s)Carb bowl venting–Electronic solenoids–Switching with purge valveEvap system operation (purging)Uses stored fuel vapors in canisterVariable type-hose to air cleaner snorkelConstant purge type-vacuum to manifold–Uses TVS and orificeEvap system operation (purging)Demand system–None at idle–Uses ported vacuum as control–Manifold vacuum does purging–Needs TVSComputer controlsOBDII diagnosticsEvap system problemsFailed purge valves / diaphragms rupturingPlugged filtersFailing TVS