Onboard Refueling Vapor Recovery; Orvr System Schematic - Chrysler 2000 LHS Owner's Manual

LH
DESCRIPTION AND OPERATION (Continued)
1 – FUEL CAP
2 – RECIRCULATION TUBE
3 – CONTROL VALVE
4 – FLOW MANAGEMENT VALVE
5 – PURGE
6 – W/LDP

ONBOARD REFUELING VAPOR RECOVERY

(ORVR)
DESCRIPTION
ORVR System Schematic and components.
OPERATION
The emission control principle used in the ORVR
system is that the fuel flowing into the filler tube
(appx. 1" I. D.) creates an aspiration effect which
draws air into the fill tube (Fig. 5). During refueling,
the fuel tank is vented to the vapor canister to cap-
ture escaping vapors. With air flowing into the filler
tube, there are no fuel vapors escaping to the atmo-
sphere. Once the refueling vapors are captured by
the canister, the vehicle's computer controlled purge
system draws vapor out of the canister for the engine
to burn. The vapors flow is metered by the purge
Fig. 5 ORVR System Schematic
7 – BREATHER ELEMENT
8 – W/O LDP
9 – CANISTER
10 – ROLLOVER VALVE
11 – FUEL TANK
12 – CHECK VALVE
solenoid so that there is no or minimal impact on
driveability or tailpipe emissions.
As fuel starts to flow through the fill tube, it opens
the normally closed check valve and enters the fuel
tank. Vapor or air is expelled from the tank through
the control valve to the vapor canister. Vapor is
absorbed in the canister until vapor flow in the lines
stops, either following shut-off or by having the fuel
level in the tank rise high enough to close the control
valve. The control valve contains a float that rises to
seal the large diameter vent path to the canister. At
this point in the fueling of the vehicle, the tank pres-
sure increase, the check valve closes (preventing tank
fuel from spiting back at the operator), and fuel then
rises up the filler tube to shut-off the dispensing noz-
zle.
If the engine is shut-off while the On-Board diag-
nostics test is running, low level tank pressure can
be trapped in the fuel tank and fuel can not be added
FUEL SYSTEM 14 - 5