Page 62 - ESP (CNG & LNG) Participant Guide

Module 8: LNG Vehicle Systems and Safety Practices

LNG Enters the Tank

 LNG is pumped into the vehicle’s fuel tank through the fill connector
 Cold LNG travels into the top of the tank, cooling some of the vapor that has been
created by the natural warming of the LNG
 The tank fills to 90% of its total capacity, leaving room for vapor to accumulate

Vapor at the Top of
the LNG Tank
Creates Pressure

 If there is sufficient vapor in the top of the tank, the vapor travels through the
pressure control (economizer) valve and ultimately to the engine
 This process continues until enough of the vapor has been used that there is not
sufficient pressure (approximately 125 psi) for the economizer valve to remain open

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