Quest Minivan XE V6-2960cc 3.0L SOHC MFI (VG30E) (1998)
Canister Purge Volume Control Valve: Description and Operation
SYSTEM DESCRIPTION
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass passage in the EVAP canister purge
volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The
opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine
conditions. When the engine is operating, the flow rate of fuel vapor from the EVAP canister is regulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control valve uses a step motor to control the flow rate of fuel vapor from the EVAP canister. This motor has
four winding phases. It operates according to the output pulse signal of the ECM. Two windings are turned ON and OFF in sequence. Each time an
ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECM does not issue the pulse
signal A certain voltage signal is issued so that the valve remains at that particular opening.