Page 22 - CNG ESP Participant Guide2024

Module 2: High-Pressure CNG Fuel System Components

Fuel Receptacle ▪ Equipped with a one-way flow check valve
o Prevents gas from flowing out of the
fuel system
▪ Should always have a dust cover
▪ Check the O-ring condition
o Missing or damaged O-ring = unable
to safely fuel vehicle

Heavy-Duty Fuel
Receptacles

▪ Many heavy-duty natural gas vehicles have two sizes of 3,600 psi fuel receptacle
o The receptacle on the left is the larger receptacle, commonly referred to as the
NGV1 Heavy-Duty (HD)
o The one on the right is the standard NGV1 receptacle.
▪ Both receptacles provide 3,600 psi fuel—but the NGV1 HD flows fuel at a faster rate

Secondary Check ▪ Redundant valve to prevent escape of gas
Valve o If receptacle check valve fails to seal
o If receptacle is damaged

NGV Essentials and Safety Practices (CNG & LNG) © 2024 AFVi All Rights Reserved Page 2-4