Crank Case Emission Control1

8/11/2019 Crank Case Emission Control1

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CRANK CASE EMISSION

CONTROL

PREPARED BY-D.B.LOKWANI(130150735005)

GUIDED BY PRO. A.S.SORATHIY A

Sub.- AMPC


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Emission Controls

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http://www.hunter.com/pub/undercar/index.htmhttp://www.hunter.com/pub/undercar/index.htm


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emission control system

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Purpose: control emissions and exhaust

from vehicleTurn the harmful gases the car

manufactures into harmless ones that

don't ruin the environmentProblem gases :

hydrocarbons (unburned) HC

carbon monoxide COnitrogen oxides NOx

sulfur dioxide SO2

phosphorus P


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Three (major) Pollutants

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Hydrocarbons (HC)

Un-burnt Gasoline

Carbon Monoxide (CO)CO results from the incomplete

combustion Fuel

Oxides of Nitrogen (NOx)NOx results from air being

overheated.


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HC

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HC results from gasoline that is not burned in theengine. This can be due from misfires, burning

rich, open loop operation, or excessive cranking.


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CO

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COresults from the incompletecombustion of organic materials.

gasoline, kerosene, natural gas,propane, coal, wood, charcoal, diesel

fuel, heating oil and almost any other

combustible material, such as tobacco

and paper.


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NOx

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Nitrogen oxides (NOx) are reactive gases

Cause a host of environmental concerns impacting adverselyon human health and welfare.

Nitrogen dioxide (NO2), in particular, is a brownish gas thathas been linked with higher susceptibility to respiratoryinfection, increased airway resistance in asthmatics, and

decreased pulmonary function. Other effects:

Principle cause of ground-level ozone formation

Contribute to acid deposition, which can damage trees at high

elevations and increases the acidity of lakes and streams,which can severely damage aquatic life

Contribute to increased levels of particulate matter by changinginto nitric acid in the atmosphere and forming particulate nitrate

combustion temperature gets above 2,500 degrees F


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Evaporation from the fuel tank. 5%

Blow-by gases which escape from the crankcase. 20-

25%

Tail pipe emissions. 60-75%

Carburetor evaporation from the float bowl on old cars.


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POLUTION

20 %

Crankcase

vapors20% Fuel

Vaporization

60% Exhaust

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Three Ways to Control Pollution

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1Improve combustion

2Capture the vapors and re-burn

them.3Treat the exhaust.


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Ways to Combat Pollution

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Capture the vapors and burn them

PCV

EGR

Charcoal Canister

Improve the combustion

Monitor mixture

Less Power

Treat the exhaust

Fewer Emission


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WHY 14.7:1

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Vapor Recovery Type Systems

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Positive Crankcase Ventilation (PCV)

Fuel Tank Vapor Recovery (VVR)


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Positive Crankcase Ventilation Uses manifold

vacuum toclean blow-bygases fromcrankcase.

Needs abreather tubefor fresh air.

Needs a PCV

valve toregulate theamount ofgases enteringthe intake

manifold.14


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PCV Operation

The PCV valve has

two funct ions:

1. To regulate the

amount of vaporentering the intake

manifold at various

engine speeds.

2. Prevent damage

from backfire.

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Regulating the PCV Vapor

Flow

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Amount

Condition

Manifold

Vacuum

Blow-by

Gases

Idle High

Vacuum

Small

Volume

H igh Speed Low Vacuum Large

Volume


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PCV (Positive Crankcase Ventilation System)

Uses engine vacuum to draw blow-by gases into the intake manifold for

reburning in the combustion chamber.

Vacuum or electronic controlled, mounted on the valve cover.


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PCV (Positive Crankcase Ventilation System)

At idle, high manifold

vacuum pulls the plunger

for minimum vapour flow

(prevents a lean air-fuel

mixture)

.

During acceleration, intakemanifold decreases. This

allows the PCV valve to

move to a center position

for maximum flow.

With engine off, a spring

pushes the valve against its

seat, closing the valve. A

backfire will also close the


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PCV Service

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Replace PCV valve every 3 years/30,000miles.

Clean the breather filter if applicable. Thevalve can be cleaned also if you dont want to

replace it. Inspect hoses for proper routing and

deterioration.

Check the air cleaner housing for oil build up.

Check PCV system function.

1) Use the PCV vacuum tester.

2) Use the tachometer and look for RPM

drop.


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PCV Trouble-Shooting Notes

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Defective PCV system can cause big timevacuum leaks. This can lead to a very fast idlespeed or stalling.

If the valve or hoses get clogged the vapors back-

up into the air cleaner clogging it too and puts oilin the air cleaner housing.

A strange problem is if a valve cover gasket startsleaking oil winds up in the air cleaner also.

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