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Valve Operation and Air Flow

In the figure below, divided by the diaphragm, the part above X is charged with atmospheric air pressure, and the part below X is charged with tank pressure. Also, the part above Y is charged with tank pressure, and the part below Y is charged with canister pressure.

If the atmospheric air pressure port is A, tank pressure port is B, and canister pressure port is C, the air flows according to pressure difference from each port as shown in the table below.

Fig 1: Valve Operation And Air Flow Diagram
G05955722Courtesy of SUBARU OF AMERICA, INC.
MAP SPECIFICATION

Condition of pressure Flow
A < B (solenoid OFF) B → C
B < C (solenoid OFF) C → B
Solenoid ON B ↔ C