crank case emission control1
TRANSCRIPT
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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.