5 GAS DIAGNOSTICS

What Goes In Must Be Consumed, If Not It Comes Out!

Steve Zack

204/21/2306/11/97

Agenda

• The Theory of 5 Gas

• Diagnostics with a 5 Gas Analyzer

The Theory Of 5 Gas

The Theory of 5 Gas

• Air Contains 77% to 78% Nitrogen, N2

• N2, 2 Elements of N

• N2 Absorbs Heat– In the Atmosphere– In the Combustion Chamber

• N2 Separates Under Pressure and Temperature

N N

Nitrogen - N2

The Theory of 5 Gas

• Remaining Air Contains 21% Oxygen, O2• O2, 2 Elements of O• O2 is an Oxidizer• Remaining Portions of Air

– Argon, Ar– Helium, He– Hydrocarbons, HC – Etc.

O O

Oxygen - O2

The Theory of 5 Gas

• Intake Valve Opens Exposing Low Pressure

• Injector Sprays Atomized HC

• HC, Gasoline– 1 Element of H - Hydrogen – 1 Element of C - Carbon

• 14.7 Psi Pushes Air and Fuel in

H C

Gasoline - HC

The Hexane Value Gas Analyzers Measure

Atomized

Liquid

GASOLINE FORMULA: 27% AROMATIC (BENZENE C6H6), 12% OLEFINS (CnH2n), 1% BENZENE (C6H6), 305PPM SULFUR (S), 11% MTBE (METHYL TERTIARYBUTYL ETHER), 2% OXYGEN (O)

OO

OO

OO

NN

H C

HCO

O

The Theory of 5 Gas

• Piston Rises in Compression Stroke, Pressure Builds

• The Compounds Will Rub Together

• This Causes Friction of the Elements

• Friction Causes Heat

The Theory of 5 Gas

• Heat Absorbed by the Elements

• O2 Absorbs Heat Separates to O and O

• HC Absorbs Heat Separates to H and C

• O2 and HC Now Vapor

O O

H CPressure and Heat

Now Vapor

The Theory of 5 Gas

• Piston Continues to Rise

• Friction Causes 2300 F

• Pressure has Increased

• N2 Will Absorb Heat at 2300 F

• N2 Will Separate to N and N, Now Vapor

Extreme Heat and Pressure

N N

Now Vapor

OO

OOO

O NN

H C

H C

OO

The Theory of 5 Gas• The Spark Plug Ignites, Pressure Increase

– Voltage is Pressure

• The O Elements Will Oxidize with N, C, and H– 2O Elements to 1C Element = CO2

– 1O Element to 2H Elements = H2O

– XO Elements to 1N Element = NOx

• Oxidation, O Elements Attaching to Other Elements

The Theory of 5 Gas

• Oxidation Creates as the Elements Collide

• All the Combined Appear as

• Oxidation Creates Energy Through Heat

• The Heat Energy Forces the Piston Down

Sparks

Sparks

Fire

H

O

H

C

O

O

N

O

OH

H

N

O

OCO

O

O O

OOON

N

H

C

H

C

O

O

The Theory of 5 Gas

• As Combustion Occurs a Good Running Engine Produces

– H2O - 2 H - Hydrogen Elements and 1 O - Oxygen Element

– CO2 - 1 C - Carbon Element and 2 O - Oxygen Elements

H

O

H

Water - H20

A Product of Combustion

C

O

O

Carbon Dioxide - CO2

A Product of Combustion

Displaces N2 in Atmosphere

The Theory of 5 Gas

• As Result of Driving Conditions Most Engines Will Produce – H2O

– HC - 1 H - Hydrogen Element and 1 C - Carbon Element

– CO - 1 C - Carbon Element and 1 O - Oxygen Element

– O2 - 2 O - Oxygen Elements

– CO2

– NOx - 1 N - Nitrogen Element and Unknown O - Oxygen Elements

The Theory of 5 Gas

• The Catalytic Converter Will Oxidize and Reduce– HC to H2O and CO2– CO to H20 and CO2– NOx to CO2 and H2O and N2

O

O O

OO2 SENSOR READS LEAN, PCM COMMANDS RICH, INCREASING CO

200mv SWITCH <100ms

C

O

H

C

N

OCO CAUSE THE CATALYST TEMPERATURE TO RISE

N

O

HC

C

O

H

C

N

O

HIGH CATALYST TEMPERATURE CAUSES ELEMENTS TO SEPARATE

H

C

N

O

C

O

H

C

N

O

H

C

N

O

O2 FROM CERAMIC SUBSTRATE COMES OUT

OO O O

OH

H C O

NN

O

CO

O COO

OXIDATION AND REDUCTION OCCURS

SO2, SULFUR DIOXIDE, ROTTEN EGG ODOR

SOO

O2 SENSOR READS RICH , PCM COMMANDS LEAN, REPLENISHING CATALYTIC CONVERTOR WITH O2

800mv SWITCH <100ms

Diagnosing 5 Gas

H CHydrocarbons - HC

Unburned Gasoline - HC

Toxicant

Diagnosing 5 Gas - HC

• Causes– Rich

– Contaminated Crankcase

– Lean

– Secondary Ignition• Spark Plugs

• Plug Wires

• Cap & Rotor

– Primary Ignition• Coil

• Low Primary Current

– Base Timing

• Causes– Preignition

– Charging System

– EGR

– Cooling System

– Engine Problems• Valves

• Rings

– Cam Timing

– Carbon• Intake Valve Throat

C O

Carbon Monoxide - CO

A Byproduct of Combustion

Colorless, Odorless, Toxicant

Diagnosing 5 Gas - CO• Causes

– Rich• MAP or MAF• TPS• IAC Closed• Injector Spray• Air Cleaner

– Evaporative Purge System– Contaminated Oil– Charging System– Engine Problems– Cam Timing– Base Timing

• Retarded

O OOxygen - O2

Unburned Oxygen - O2

Diagnosing 5 Gas - O2• Causes

– Lean• IAC Open• Vacuum Leak• Injector Spray• Fuel Volume

– Secondary Ignition– Primary Ignition– Base Timing– Preignition– Charging System– Cooling System– Engine Problems– Exhaust Valve– Carbon – Exhaust Leak

• Dilution

N O NO

O

+ = NOx

NO + NO2 = NOx

A Product of Combustion

NOx

Oxides of Nitrogen

Brown Color, Toxicant

Nitrogen Dioxide

Colorless, Odorless, Toxicant

Nitrogen Oxide

Diagnosing 5 Gas - NOx• Causes

– Lean

– Base Timing• Advanced

– Preignition

– EGR• EGR Flow

– Cooling System• Pump Vanes• Thermostat• Fan & Fan Belts• Coolant Level & Quality• Jacket Corrosion

– Cam Timing

– Exhaust Valve

– Carbon• Cylinder & Piston

Summary

Summary• NOx HC CO O2 CO2

• Rich L H H L L• Contaminated Oil L H H L L• Lean H H L H L• Secondary Ignition L H L H L • Primary Ignition L H L H L• Base Timing H H L H L• Preignition H H L H L• Charging System L H H H L• EGR H H L L L• Cooling System H H L H L• Engine Problems L H H H L• Cam Timing H H H L L• Exhaust Valve H H L H L• Carbon H H L H L• Exhaust Leak L L L H L• Test at 1000 RPM, Engine at Operating Temperature, H - High, L - Low

Fuel, OBD

Ignition

OBD

Mechanical

Summary

• NOx < 150 PPM to 300 PPM Max

• HC < 100 PPM Max

• CO < 0.5 % Max

• O2 < 0.5 % Max

• CO2 > 12 % to 15 % Min• Test at 1000 RPM, Engine at Operating Temperature

• Testing After the Catalytic Converter

10:1 14.3:1 15.1:1 18:1

14.7:1Stoichiometric

RICH O2 PCM Input O2 PCM Input LEAN

600mv O2 300mv O2 PCM Command PCM Command

Low IPW High IPW

600 PPM

500 PPM

400 PPM

300 PPM

200 PPM

100 PPM

0 PPM

15%14%13%12%11%10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0%

CO2

NOx

O2

HC

CO