Emissions

1. Emissions 5-Gas

2. Vehicular Air Pollutants Fuel Evaporation 20% Crankcase Vapors 20% Exhaust 60%

3. Emitted Gases • During combustion various reactions take place between the combusting air and fuel mixture • Five gases make up the majority of the resulting exhaust • Hydrocarbons (HC) • Carbon Monoxide (CO) • Carbon Dioxide (CO2) • Oxygen (O2) • Oxides of Nitrogen NOx

4. Optimal Combustion • Input • Air • 21% Oxygen • 78% Nitrogen • 1% Argon, CO2 and other gasses • Fuel (C8H15) • Output • H20 • CO2 • Nitrogen

5. Hydrocarbons (HC) • Hydrocarbons are unburned fuel • Hydrocarbons are made up of Hydrogen and Carbon • Gasoline (C8H15) • Ethanol (C2H6O) • Methanol (CH4O) • Propane (C3H8) • Excessive HC levels in the exhaust indicate incomplete combustion • HC should be less than 50 ppm

6. Carbon Monoxide (CO) • Poisonous odorless gas • Indicates a rich air/fuel mixture • Not enough oxygen present to combine with all of the fuel to produce CO2 • Should be less than .5%

7. Carbon Dioxide (CO2) • Harmless gas • Indicates efficient combustion • Enough oxygen is present to combine with the carbon and produce CO2 • Should be 12% - 17% • Greenhouse gas

8. Oxygen (O2) • Used during combustion • Atmosphere contains 21% • Exhaust contains .5% or less • If A/F ratio is rich barely any will be present after combustion • If A/F ratio is lean more will be present after combustion • Extremely high levels of O2 may indicate an exhaust leak or an improperly disabled AIR injection system

9. Oxides of Nitrogen (NOx) • Compound made up of one nitrogen atom and a number of oxygen atoms • NO, NO2, NO3, NO4 • NOx is produced when combustion temperatures reach 1500 F • NOx is produced rapidly when combustion temperatures reach 2500 F • NOx reacts with HC, O2 and sunlight to produce smog

10. Emissions Testing • Static • Test is done at idle • Gasses are measured as a percentage of the exhaust (I.e. PPM, %) • Illinois tests 1968-1979 vehicles this way • Illinois tests AWD and 4WD vehicles this way • Dynamic • Called the IM240 • Test lasts up to 240 seconds • Vehicle is driven on a dynometer to simulate city and highway driving • Illinois tests 1980-1995 vehicles this way • Emissions are measured by total weight of emissions • Grams per mile

11. IM240

12. IM240

13. IM240

14. Exhaust Gas Analysis • Two gas analyzers • HC and CO • Four gas analyzers • HC, CO, CO2, O2 • Five gas analyzers • HC, CO, CO2, O2, NOx

15. Emissions Testing • Pre-Cat (in front of the catalytic converter) • Lets you test exactly what is coming out of the engine • Post-Cat (behind the catalytic converter) • Tests what is actually coming out of the tailpipe • Engine efficiency + converter operation • Ensure the catalytic converter is up to temperature • Run engine at 2500 RPM for two minutes

16. Analyzer Hook-up Attach analyzer probe here for Pre-Cat readings Attach analyzer probe here for Post-Cat readings You may have to drill a small hole in the exhaust pipe to take a pre-cat reading (either weld it shut or install a fitting and plug)

17. Analyzer Hook-up

18. Emissions Diagnosis • Possible gas combinations • Low CO/High O2 • Indicates a lean mixture • High CO/Low O2 • Indicates a rich mixture • High HC/High O2 • Indicates a misfire/incomplete combustion • High CO2 • Indicates efficient combustion • High Nox • Indicates high combustion chamber temperatures

19. Stoichiometric Gas Chart - HC Rich Lean 1000 HC (ppm) 750 Exhaust Level ppm 500 HC 100 ppm or less good 250 10:1 20:1 “Best” Range 14.6 to 14.8 to 1 Air/Fuel Ratio

20. Stoichiometric Gas Chart - CO Rich Lean 15% CO Exhaust Level % CO About 1 % Good 0% 10:1 20:1 “Best” Range 14.6 to 14.8 to 1 Air/Fuel Ratio

21. Stoichiometric Gas Chart - O2 Rich Lean 15% Exhaust Level % O2 .1 to 7 typical- more, better 0% 10:1 20:1 “Best” Range 14.6 to 14.8 to 1 Air/Fuel Ratio

22. Stoichiometric Gas Chart -CO2 Rich Lean 15% Exhaust Level 0% CO2 about 8% 10:1 20:1 “Best” Range 14.6 to 14.8 to 1 Air/Fuel Ratio

23. High CO/Low O2 • Indicates a rich mixture • Possible Causes • Leaking fuel injector • High fuel pressure • Faulty ECM input • Low O2 Voltage • Thermostat stuck open • Plugged air filter • Faulty canister purge valve • Fuel saturated crankcase • Leaking carb gaskets, sticking choke etc.

24. Low CO/High O2 • Indicates a lean mixture • Possible Causes • Clogged injectors • Vacuum leak • Low fuel pressure • Faulty ECM input • High O2 voltage • Low float level, plugged jets, improper car adjustment

25. High HC/High O2 • Indicates a misfire (O2 and HC coming into the engine but are not being completely burned) • CO may be low, high, or normal • Possible causes • Ignition misfire • Plugs, Wires, Cap, Rotor, Timing • Low compression • Lean misfire • Rich misfire • Sticking EGR

26. High NOx • Indicates high combustion temperatures • Possible causes • Inoperative EGR • Lean mixture • High engine temperatures • High intake air temperatures • High compression ratio

27. High CO2 • Indicates efficient combustion • Uncatalyzed levels around 13% indicate efficient combustion • CO2 levels should increase when the catalytic converter starts operating • 14.5 % CO2 indicates combustion is efficient and catalytic converter is working

28. Low CO2 • If CO2 is below 10% proper combustion/catalyzation is not occurring • CO greater than .5%, O2 greater than CO • Catalyst isn’t working properly • CO greater than .5%, O2 lower than CO • Catalyst isn’t working • Air injection not providing enough O2 to catalyst • Missing downstream pipe • Switching valve problems • Engine pumping out too much HC or way to much CO