Originally posted by shorto85 on Feb/15/04
Ok I see people asking about various things that have to do with smogging their car. I found some great links to help everyone out!
Aftermarket, Performance, and Add-On Parts Regulations - Replacement Parts Guidelines
Stories of cars required to be Refereed
Thank you to Cory for the following information:
California Automotive Emission Information
As of August 2002
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What does it take to have combustion? (what goes into the combustion chamber)
a) 78% Nitrogen, 21% Oxygen, 1%Other
b) Fuel (aka HC)
c) Ignition (spark)
d) Compression -
What is the Combustion Process Objective?
Burn ALL of the Fuel (Hydrocarbon or HC) while using up ALL the Oxygen (O). -
Five reasons for IMCOMPLETE combustion:
a) Quench areas due to combustion chamber design
b) Variations in air/fuel ratio
c) High combustion temperatures due to engine load
d) Carbon build up
e) Engine design -
What causes smog to form?
[HC + Nox + Sunlight] = Smog -
Carbon monoxide (CO)
a) Carbon monoxide is one carbon atom and one oxygen atom
b) It is measured in percentage (%)
c) CO forms when there is a SHORTAGE of oxygen
d) The Higher the CO % the RICHER the mixture
e) The Lower the CO % the LEANER the mixture -
When you get your smog results:
CO is a good indicator if the system is too RICH but is a poor indicator if the mixture is too LEAN -
HYDROCARBONS: (HC)
a) HC are unburned fuel that passed through the combustion chamber (incomplete combustion)
b) They are measured in parts per million (PPM) -
Oxides of Nitrogen: (NOx)
a) Oxides of Nitrogen are One Nitrogen atom and a varying oxygen atom
b) We measure NOx using Parts Per Million (PPM)
c) NOx is produced at a temperature of 2500 degrees -
NOx is controlled by use of:
a) low compression ratios
b) camshaft timing
c) Ignition timing
d) EGR Systems (not present on an Integra/Civic)
e) 3-Way converters -
Carbon Dioxide: (CO2)
a) Carbon Dioxide is formed when one Carbon Atom (from HC) bonds with two atoms of oxygen (from O2)
b) We measure it in percentage (%)
c) CO2 is produced in two places:
Low at rich mixtures
low at lean mixtures
higest at optimum combustion a/f ratio (14.7:1, stoichiometric) -
Oxygen: (O2) a) self explanatory, it is measured in percentage (%)
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What is a lean misfire?
a) It is when there is too much AIR and not enough FUEL present to support combustion!
b) Little fuel passes through unburnt = High HC
c) Lowest at rich mixtures, slightly higher at stoichiometric (14.7:1) and highest at lean mixtures -
What is a rich mixfire?
a) When there is to much fuel and not enough oxygen present to support combustion, (will give you high HC and CO from test results)
General Rules that are good to know!
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O2, CO, & CO2 Relationships:
a) High O2, low CO & low CO2 = lean
b) Low O2, high CO & low CO2 = rich
c) Low 02, low CO & high CO2 = OK (good) -
If the mixture is STOICHIOMETRIC, then the O2, and CO should be very low and about equal
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If CO exceeds O2 than the A/F ratio is richer than ideal
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If O2 exceeds CO than the A/F ratio is leaner than ideal
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When the air/fuel mixture is either rich or lean, the levels of oxygen and carbon monoxide will be opposite one another.
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What is Lambda?
a) ideal a/f = 1.0 lambda
b) rich a/f = lower numbers (.9 and lower)
c) lean a/f = higher numbers (1.1 and higher) -
What is ideal operating A/F?
a) ideal = 14.7:1 = stoichiometric = lambda
b) richer = 13.5:1
c) lean = 15.5:1 -
How to check for an internal vacum leak!
Watch HC, CO and O2 while adding propane to the crankcase. If HC and O2 go down and CO goes up, then you have an internal manifold leak.
Positive Crankcase Ventilation (PCV)
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Introduced in CA in 1961 and federally in 1971
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Crankcase emissions are responsible for 20% of total emissions!!!
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PCV systems reduce and control HC emissions
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There are only two types of systems used on today’s cars:
a) Type 3: Sealed System
non vented fill cap
tube to air cleaner
does not have a PCV valve
b) Type 4
non vented filler cap
PCV Valve (may or may not have)
tube from air cleaner to valve cover -
Operational Modes (ie. On/off, open closed etc etc)
a) Min. flow: (high engine vacum)
It is in this state when in idle, low speed and deceleration
b) Max. flow:
It is in this mode while cruising
c) Off/Closed: (“0” engine vacum)
It is in this mode while Cranking, Starting, WOT and Intake Backfire -
Blowby is the gases that escape past piston rings into the crankcase.
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If system is failing to operate properly operator will complain of:
a) If PCV valve stick in the Max. flow position: Will result in Hard starting an rough idle, the engine will be running to lean
b) If PCV valve sticks in the Off/Closed position:
Poor fuel mileage and oil in the air cleaner or intake manifold, engine running to rich -
On a regular tune up it does not hurt to replace the PCV valve and the PCV inlet filter if applicable (they are only a few dollars in most cases)
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To test for excessive fuel in the crankcase resulting from blowby:
Allow the PCV valve to pull fresh air. If CO decreses by more than 1.0% the crankcase is contaminated with fuel. The owner should change the oil before performing a smog inspection. -
If the PCV valve is plugged off the idle rpm should drop 50 rpm if the system was working properly
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Will not pass visual if PCV system lines are replaced with heater hose!
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Bad things without it working properly:
a) low engine temps
b) oil can thicken and sludge prematurely -
Breathers: you will not pass visual with one of those pep boys air breathers…I know there is a common topic on it but they do not serve a good pupose and only create a hole in the pcv system and you will not be putting the air back into the car to recycle it…ie you might not even pass the actual test with one on there! And if you do it would not be by much!
