Page 66 - CNG/ LNG ESP Participant Guide 2024
P. 66

Module 8: LNG Vehicle Systems and Safety Practices

             Methane Detection
             System












                                  ▪  Two Zones
                                     o  Engine compartment
                                     o  Cab









           Lesson 8.3: Unsaturated LNG Fuel Systems and Components

             What is              ▪  LNG that has NOT been slightly warmed at the LNG station by heat exchanger(s)
             Unsaturated LNG?     ▪  Unsaturated fuel is colder than saturated
                                      o  Saturated refers to the amount of heat that has been absorbed by the fuel

             Comparing                         Saturated                           Unsaturated
             Saturated and                 (Warmed ~ -200⁰F)                      (Cold ~ -230⁰F)
             Unsaturated LNG       ▪  No accumulator                   ▪  Accumulator required
                                   ▪  LNG storage tank                 ▪  LNG storage tank with pump
                                   ▪  Fuel delivered via tank pressure    ▪  Fuel delivered via pump
                                   ▪  Tank pressure created by warming   mechanism
                                     the fuel                          ▪  Pump mechanism operated by
                                   ▪  Low pressure into airstream        engine’s power steering pump
                                   ▪  Requires an ignition system      ▪  High pressure direct injection
                                   ▪  Dedicated LNG operation only – no   into engine cylinder
                                     diesel on board                   ▪  Requires diesel as ignition source










                                           NGV Essentials and Safety Practices (CNG & LNG)                            © 2024 AFVi All Rights Reserved    Page 8-8
   61   62   63   64   65   66   67   68   69   70   71