Forester F4-2.5L SOHC (2004)
Refueling Vapor Recovery System: Description and Operation
On-board Refueling Vapor Recovery (ORVR) System
GENERAL
The on-board refueling vapor recovery system allows the fuel vapors in the fuel tank to be introduced directly into the canister through the vent valve
when the fuel tank inside pressure increases as a result of refueling.
The diagnosis of the system is performed by monitoring the fuel tank inside pressure data from the fuel tank pressure sensor while forcibly closing the
drain valve.
OPERATION
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While driving
On-board Refueling Vapor Recovery (ORVR) System
Since the back side of the diaphragm in the pressure control solenoid valve is open to the atmosphere, the diaphragm is held pressed by the
atmospheric pressure in the position where only the external air is introduced into the canister. When the fuel vapor pressure acting on the other
side of the diaphragm increases and overcomes the atmospheric pressure, it pushes the diaphragm and opens the port through which the fuel
vapors make their way to the canister.
-
While refueling