emission controls l.
Skip this Video
Loading SlideShow in 5 Seconds..
Emission Controls PowerPoint Presentation
Download Presentation
Emission Controls

Loading in 2 Seconds...

play fullscreen
1 / 85

Emission Controls - PowerPoint PPT Presentation

  • Uploaded on

Emission Controls. Before beginning to understand emission controls you should know the reason why emission controls were installed into the automobile. 1. To reduce the amount of pollutants entering the atmosphere . . Emission Controls. Smog is a term developed from smoke and fog

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

Emission Controls

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
emission controls2
Before beginning to understand emission controls you should know the reason why emission controls were installed into the automobile.

1. To reduce the amount of pollutants entering the atmosphere .

Emission Controls
emission controls3
Smog is a term developed from smoke and fog

Smog is form when airborne pollutants is formed with oxygen and other atmospheric gasses to produce a grayish yellow smoke. The resulting smoke is called photochemical smog.

Emission Controls
  • Smog is can be a major problem in larger cities (New York and LA)
  • Smog can be harmful to
    • A. Humans
    • B. Plants
    • C. Animals and even effect paint rubber and other materials.
  • One of largest producer of photochemical smog is the automotive internal combustion engine.
  • The EPA (environmental protection agency) begin putting restriction on automotive manufactories in the mid 60.
motor vehicle emissions
Motor Vehicle Emissions
  • Motor vehicle emission are emission produce by motor vehicles. They include
    • A. Hydrocarbons (HC)
    • Carbon monoxide (CO)
    • Oxides of nitrogen (NOx)
exhaust gasses
Hydrocarbons (HC) are emission of unburned petroleum products being released into the atmosphere.

All petroleum products and made of hydrocarbons (hydrogen and carbon compounds) this includes:

Gasoline LP-gas.

Diesel motor oil.

Exhaust Gasses
exhaust gasses8
Hydrocarbons are produced because of incomplete fuel combustion or fuel evaporation.

Hydrocarbons emission is considered a hazardous form of air pollution because of.



Lung irritation.

And possibility cancer.

Exhaust Gasses
exhaust gasses9
Exhaust Gasses
  • In north Carolina a vehicle must not exceed 220 ppm of hydrocarbons emissions.
  • High hydrocarbon emission are the results of a:
    • cylinder misfire.
    • Improper ignition timing
    • Worn cylinder rings (pumping oil into the combustion chamber
exhaust gasses10
Exhaust Gasses
  • Carbon monoxide emission are exhaust emission that is the result of partially burned fuel.
  • A high carbon monoxide emission can be caused by a:
    • Restricted or dirty air cleaner.
    • Advance ignition timing.
    • Clogged fuel injectors.
exhaust gasses11
Exhaust Gasses
  • Oxides of nitrogen, (NOx) are emission produced by extreme heat.
  • Air consist of approximately 79% nitrogen and 21% oxygen
  • When combustion chamber temperature reaches 2500 degrees F or 1370 degrees C nitrogen and oxygen combine to produce oxide of nitrogen (NOx)
In North Carolina the standard for Carbon Monoxide is 1.2 % of the total exhaust output.


HC 220 ppm

CO 1.2%

Exhaust output

exhaust gasses13
Exhaust Gasses
  • Oxides of nitrogen is responsible for the dirty brown color is SMOG.
  • NOx is a eye and respiratory irritant.
  • Newer high compression, learn air fuel mixture and hotter running engine produces more NOx than earlier engine.
exhaust gasses14
Exhaust Gasses
  • The same factors that increases NOx will tend to improve fuel mileage and lower HC and CO2 production.
  • This means that to increase fuel economy and lower HC and CO2 production NOx will increase.
  • For this reason emission controls have beedn added to lower all form of emissions
exhaust gasses15
Exhaust Gasses

NOx increases

HC increases



14.7 – 1 AFR

Hc and Co decreases

NOx decreases

exhaust gasses16
Exhaust Gasses
  • Before understanding emission controls we need to first understand where they come from.
  • Particulates: are solid particle of carbon soot and fuel additives that blow out the tail pipe.
  • Engine crank case blow by. Caused by heating of oil and unburned fuel vapors that blow past the engine rings.
exhaust gasses17
Exhaust Gasses
  • Fuel vapors: different chemicals that enter the atmosphere as fuel evaporates.
  • Engine exhaust gasses: are harmful chemical that are produced inside the combustion chamber and are blow out the tail pipe.



Solid particulate

Catalytic Converter

Exhaust manifold

Fuel Tank


Fuel Pump





exhaust gasses19
Exhaust Gasses
  • Automotive manufactures agree the best way to lower exhaust emission is to burn all the fuel entering the combustion chamber.
  • Modern engine have introduced several modification to ensure all fuel entering the combustion chamber is burned.
exhaust gasses20
Exhaust Gasses
  • Some engine modification are:
  • Lower compression ratio, by lowering compression ratio vehicle can burn unleaded fuel. The use of unleaded fuel allows for catalytic converters that help reduce HC and CO emissions.
  • Lower compression ratio also lower combustion temperature reducing NOx emission.
exhaust gasses21
Exhaust Gasses
  • Smaller combustion chambers, allows for more heat to remain inside the combustion chamber that can aid in the burning of fuel.
  • Reduce quench areas, the areas between the piston and the cylinder head is the quench area. If this areas is to close fuel will not burn completely increasing HC and CO emissions. Modern engine are design to reduce high quench areas.
exhaust gasses22
Exhaust Gasses

Quench area

exhaust gasses23
Exhaust Gasses
  • Decrease valve overlap, is used to decrease exhaust emission. A larger valve overlap increases power but dilutes incoming fuel mixture and requires a richer air fuel mixture at lower engine speed therefore increasing HC and CO emissions.
exhaust gasses24
Exhaust Gasses


Intake Exhaust

exhaust gasses25
Exhaust Gasses
  • Higher combustion chamber temperature, are used to reduce HC and CO emissions.
    • Today vehicles used hot thermostats than earlier model helping to increase combustion chamber temperature.
  • Leaner air-fuel mixtures help fuel burn better lower HC and CO emissions.
  • Wider spark plug gaps, are used to burn the leaner fuel mixture and helps prevent spark plug fouling.
exhaust gasses26
Exhaust Gasses

Thermostats are now 190 degrees

Wider spark plug gap

Some are .080 thousands

learning quiz
Learning Quiz
  • 1. When is photochemical smog formed?
  • A. when airborne pollutants is formed with oxygen and other atmospheric gasses
  • B. When Oxygen is mixed water inside the catalytic converter.
  • C. When exhaust gasses is heated to over 2500 degrees
  • D. All the above
learning quiz28
Learning Quiz
  • 2. Smog can be harmful to:
    • A. Humans
    • B. Plants
    • C. Rubber and medals
    • All the above
learning quiz29
Learning Quiz
  • 3.Technician A says CO is a hazardous exhaust emission. Technician B says HC is a hazardous exhaust emission. Who is correct?
    • A. Technician A only
    • B. Technician B only
    • C. Both technician A and B
    • D. Neither technician A nor B
learning quiz30
Learning Quiz
  • 4. Oxides of Nitrogen is produced when:
    • A. Combustion chamber temperature is to cold.
    • B. Combustion chamber temperature is too hot.
    • C. Atmospheric condition is humid.
    • D. all the above
learning quiz31
Learning Quiz
  • 5. High hydrocarbon are caused by:
    • A. Cylinder misfire
    • B. Dirty air filter
    • C. Low fuel pressure
    • D. Defective air filter.
learning quiz32
Learning Quiz
  • 6. A rich fuel mixture will cause and increase in:
    • A. Hydrocarbons
    • B. Oxides of Nitrogen's NOx
    • C. Both a and B
    • D. Neither A nor B
learning quiz33
Learning Quiz
  • 7. In North Carolina the maximum amount of Hydrocarbon emission allowed by a vehicle is:
    • A. 1000 ppm
    • B. 1.2% by exhaust volume
    • C. 220 ppm
    • D. 1% by exhaust volume
learning quiz34
Learning Quiz
  • 8.Technician A says Oxides of Nitrogen emission increases when combustion chamber temperature decreases. Technician B says Hydrocarbon emission is the result of a cylinder misfire. Who is correct?
    • A Technician A only B. Technician B only
    • C. A and B D. Neither A nor B
learning quiz35
Learning Quiz
  • 9. The best way to decrease exhaust emission is to:
    • A. Increase valve overlap.
    • B. Increase compression Ratios.
    • C. Increase combustion chamber size.
    • D. Burn all fuel enter the combustion chamber.
learning quiz36
Learning Quiz
  • 10.Technician A says crankcase blowby is not a source of vehicle emission. Technician B says modern vehicle use unleaded fuel to increase emissions and allow for the use of catlic converters. Who is correct?
  • A. Technician A only B. Technician B only
  • C. A and B D. Neither A nor B
vehicle emission control systems
Vehicle Emission Control Systems
  • There are several different types of emission control system used on modern vehicles.
    • Positive crankcase ventilation system (PCV) is used to recalculate engine crankcase fumes back into the combustion chamber.
vehicle emission control
Vehicle Emission Control
  • A PCV valve uses manifold vacuum to draw blow-by gasses from the engine into the intake manifold for reburying by the engine.
  • In earlier years automotive manufactories uses road draft tubes to remove crankcase blowby gasses.
vehicle emission control39
Vehicle Emission Control
  • The uses of road drift tube allowed for blowby gasses containing HC, CO, particulates, sulfur and small amounts of water to be vented in the atmosphere.
  • At idle when there is high engine vacuum the PCV value is pulled open to remove blow-by gasses from inside the engine.
vehicle emission control40
Vehicle Emission Control
  • At part throttle when vacuum is lower a spring inside the PCV valve forces the valve partially closed. But still allows for some blowby gasses to be vented back into the intake manifold for burning by the engine.
vehicle emission control41
Vehicle Emission Control

When engine Vacuum is High

PCV valve plunger is nearly


When engine vacuum is low plunger

Opens. Allowing exhaust gasses into




evaporative emissions control systems evap
Evaporative Emissions Control SystemsEVAP

The EVAP system prevents Hydrocarbons in the form of fuel vapors from entering the atmosphere even when the vehicle is not running.

An EVAP system is considered a closed system.

Fuel vapor are stored in a charcoal canister when the engine is off.

evaporative emissions control systems evap44
Evaporative Emissions Control SystemsEVAP
  • When the engine is started vacuum pulls fuel vapors into the engine for burning.
  • EVAP system different from per emission vehicle because no fuel or vapor is vented into the atmosphere.

Unvented Fuel Cap

Rollover Valve

Intake Manifold Vacuum

Charcoal Canister

Fuel Tank

A rollover valve is uses to prevent fuel spillage in case of a rollover.
  • A liquid-vapor separator is sometime used to prevent liquid fuel from entering the charcoal canister.
  • A charcoal canister is used to store fuel vapor when the engine is not operating.
Most modern vehicles electrically control the EVAP system to ensure a cleaner burning engine.
  • The EVAP system uses purge lines to connect the fuel tank to the charcoal canister and the intake manifold.

12 Volts with engine on


EVAP Solenoid

Rollover Valve

Fuel Tank

Charcoal Canister

enhanced evap system
Enhanced EVAP system
  • An enhanced EVAP system has the following additional components.
    • Fuel tank pressure sensor: This sensor monitor internal fuel tank pressure
    • Canister Vent Solenoid: An electrically operated solenoid that replaces the Fresh air valve on earlier systems
    • Service Port: is a test point located in the engine compartment and is used for testing the EVAP system
enhanced evap system50
Enhanced EVAP system
  • A normally open purge solenoid allows fresh air to enter the charcoal when in purge mode.
  • An enhanced EVAP system requires the uses of a bi-directional scan tool for several diagnostic procedures.

12 Volts When ignition is on

EVAP Solenoid



Fuel Tank Pressure Sensor

Test port

Rollover Valve

Fuel Tank

Charcoal Canister

exhaust gas recirculation system egr
Exhaust Gas Recirculation System (EGR)
  • An EGR system has two important jobs
  • 1. The recirculation system is used to burn un-burns gasses (HC and CO) By recirculation of un-burn gasses lower emissions can be achieved.
  • 2.By Lowering combustion chamber temperature. By lowering combustion chamber temperature NOx emission can be lowered.
exhaust gas recirculation system egr53
Exhaust Gas Recirculation System (EGR)

EGR Control Solenoid PCM Controlled

Vacuum Line

Exhaust Gasses

To EGR valve

EGR Valve

Vacuum source



Vacuum Gauge

Vacuum off throttle

Exhaust Gasses

Exhaust Gasses to Engine

exhaust gas recirculation system egr55
Exhaust Gas Recirculation System (EGR)
  • Later model vehicles use an electronic EGR value.
  • The PCM is used to control the flow of vacuum to the EGR valve.
  • By controlling vacuum to the EGR valve better exhaust gas metering can be obtained.
electronic egr valve
Electronic EGR Valve


EGR Solenoid


Throttle Position Sensor

Vacuum present when Solenoid open by PCM

To better control EGR flow later model vehicles Have begin using digital EGR valves.
  • A digital EGR valve is constructed using 3 EGR valve and 3 Electrical solenoid
top of digital egr valve
Top of Digital EGR Valve


12 from ignition


Bottom of Digital EGR valve

Ports to Intake manifold

emission quiz
Emission Quiz
  • 1.Two important job or the EGR valve is to:
    • A. Increases ignition timing and lower compression ratio.
    • B. Increase HC and CO emissions
    • C. Decrease HC emission and increase ignition timing.
    • D. Recirculation of unburned gasses and lower combustion chamber temperature.
emission quiz62
Emission Quiz

2.Technician A says that a PCV valve is used to remove blow-by from the crankcase. Technician B says the PCV valve is used to prevent HC from being vented into the atmosphere. Who is correct?

A Both A and B B. Neither A nor B

C. A only D. B only

emission quiz63
Emission Quiz

3. Technician A says that the EGR valve should operate at idle with the engine cold. Technician A says the EGR flow should increase combustion chamber temperature. Who is correct?

  • A. Technician A only
  • B. Technician B Only
  • C. Both A and B
  • D. Neither A nor B
emission quiz64
Emission Quiz
  • 4.Technician A says lower combustion chamber temperature will increase NOx. Technician B says increasing combustion chamber temperature will lower HC. Who is correct.
  • A. Technician A only
  • B. Technician B only
  • C. Both A and B
  • D. Neither A nor B
emission quiz65
Emission Quiz
  • 5.Technician A says NOx is not a harmful exhaust emission. Technician A says that O2 is not a harmful exhaust emission. Who is correct?
  • Technician A only
  • Technician B only
  • Both Technician A and B
  • Neither A nor B
emission quiz66
Emission Quiz
  • 6. A says a lean misfire can be caused by stuck closed EGR valve.
    • A. True
    • B. False
emission quiz67
Emission Quiz
  • 7. Photochemical SMOG is harmful to:
    • A. Humans
    • B. Plants
    • C. Rubber and plastic
    • D. All the Above
emission quiz68
Emission Quiz
  • 8. Technician A says the charcoal canister is used to store fuel vapors. Technician B says the charcoal canister vents fuel vapor into the intake manifold. Who is correct?
  • A. Technician A only
  • B. Technician B only
  • C. Both A and B
  • D. Neither A nor B
emission quiz69
Emission Quiz
  • 9. Digital EGR valves are controlled.
    • A. Mechanically
    • B. By the PCM
    • C. Both A and B
    • D. Neither A nor B
emission quiz70
Emission Quiz
  • 10. Technician A says fuel vapor from the fuel tank should be vented into the atmosphere. Technician B says a defective PCV valve can cause engine oil to become diluted. Who is correct?
    • A. Technician A only B. Technician B only
    • C. Both A and B D. Neither A nor B
catalytic converters
Catalytic Converters
  • In the mid 70s automotive manufacture begin installing catalytic converters to assist in meeting tougher emission standards.
  • A Catalytic is a material that can speed-up chemical action without changing itself.
catalytic converters72
Catalytic Converters
  • Automotive catalytic converter are made of platinum, palladium and rhodium or a combination of these materials.
  • Platinum and palladium are used to change HC and CO into CO2 and Water.
  • Rhodium acts to reduce NOx emissions
catalytic converters73
Catalytic Converters
  • Due to enhance emissions standard later model catalytic converters now use cerium to attract and release oxygen inside the converter to aid in the process of changing HC and CO to CO2 and H2o
catalytic converters74
Catalytic Converters
  • The catalyst agent inside a catalytic converter is either ceramic beads or a honeycomb-shaped blocks.
  • All catalytic converters are encased in a stainless steal housing.
  • NOTE: stainless steal is used on newer vehicle with catalytic converters because the production of water will rust traditional exhaust system medals in only a few years
catalytic converters75
Catalytic Converters

Catalytic Converter

CO2 H2o

HC and CO


Exhaust Flow from engine through converter

catalytic converters76
Catalytic Converters
  • Stainless steal catalytic converter housing are design to resist heat.
  • Before the catalytic converter can operate an operating temperature of around 300 degrees F must be reached.
catalytic converters77
Catalytic Converters
  • This is a honey-comb block type catalytic converter.
  • Exhaust gasses flow thru the honey-comb block
catalytic converters78
Catalytic Converters
  • There are a few different types catalytic converters.
    • Monolithic Converter
    • Two way converter
    • Three way converter
    • Dual bed converter
catalytic converters79
Catalytic Converters
  • Monolithic converter uses a ceramic honey-comb catalytic
  • Small ceramic beads converter are referred to as a pellet type catalytic converter
catalytic converters80
Catalytic Converters
  • Two way catalytic converters only convert HC and CO
  • With a two way converter NOx is not converted
  • Two way converter are coated with platinum only
  • Two way converter are sometime referred to as oxidation converters
catalytic converters81
Catalytic Converters
  • Three way catalytic converters can convert all three exhaust gasses
    • HC
    • CO
    • NOx
catalytic converters82
Catalytic Converters
  • A three way catalytic converter is usually plated with rhodium and platinum
  • Three way converter are also called reduction converters.
catalytic converters83
Catalytic Converters
  • Dual bed catalytic converter is an oxidation and reduction converter built into one unit.

CO, HC and NOx

CO2 and H20

Mixing Chamber

catalytic converters84
Catalytic Converters
  • Dual bed catalytic converters must be at an operating temperature of 130 degrees F
  • When the engine is cold additional air is forced into the exhaust manifold to aid in the burning and reduction of HC and CO
catalytic converters85
Catalytic Converters
  • On a warn engine air is forced into the converter to aid in burning exhaust gasses.
  • As exhaust gasses flows iinto the front part of the converter HC,CO and NOx is reduced.
  • As exhaust flow into the mixing chamber additional air is added to continue the burning process.
  • Exhaust gasses is the passed into the rear part of the converter to reduce HC,CO2 and NOx ever more.