Page 198 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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182 Automobile mechanical and electrical systems

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Figure 2.206 Positive crankcase ventilation (PCV) system oil separator on the side of a block:
1, PCV valve; 2, PCV hose; 3, crankcase vent oil separator; 4, crankcase vent oil separator
retaining bolt. (Source: Ford Motor Company)

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Figure 2.207 Positive crankcase ventilation (PCV) connection from rocker cover to the air
cleaner box: 1, PCV hose to valve cover connector; 2, PCV hose; 3, PCV hose to air cleaner
connector. (Source: Ford Motor Company)

2.4.6.2 Evaporative emission control
Safety fi rst Fuel vapour and particularly petrol vapour is harmful. It is given off from petrol at

Fuel vapour, particularly petrol quite low ambient temperatures. Fuel is stored in underground tanks to reduce
(gasoline) vapour, is harmful. vapour formation. However, during fi lling up and when fuel is in the tank, vapour
can escape into the atmosphere. Modern vehicles are fi tted with fuel systems
that prevent vapour loss from the vehicle ( Fig. 2.208 ).
An evaporative emission control system (EVAP) has a sealed tank and fuel lines
( Fig. 2.209 ). It allows for expansion and reuse of the fuel through a charcoal
canister ( Fig. 2.210 ). Air can pass through but the fuel vapour is trapped. To
prevent the fi lter becoming saturated it is cleaned, or purged, by drawing air