WEICHAI & PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY.COM SYSTEM OVERVIEW STOICHIOMETRIC, RICH BURN CONTROL The 4G engine control module is the backbone of the EControls control system. Proven in a multitude of applications around the world, the 4G based engine control system delivers reliable operation and optimal engine operation no matter the environment. The 4G engine control system for highly regulated emission countries enables operation at the stoichiometric air / fuel ratio with Rich Burn and a three- way catalyst (TWC). Stoichiometric engine operation ensures that there is precise amount of air delivered to completely burn all the fuel.
The stoichiometric Air Fuel Ratio (AFR) for natural gas is 17.7:1 and for propane is 15.5:1. Figure 1 shows the required 4G engine control system configurations for Propane (VPG), Natural Gas (NG) and Bi-Fuel (VPG and NG) with the TWC. Figure 1 WP4GNA Non-Emergency Schematic Bi-FUEL The 4G Engine Controls System has full engine software control authority, therefore switching from Natural Gas (NG) to Propane (LPG/VPG) fuel is a software command from the operator console or a switch input into the 4G ECM. The Weichai WP04GNA engine is capable of operating in bi-fuel mode starting from VPG/LPG and switching to NG after the NG pressure develops from operation.
With the proper valve and sensor arrangement the fuel supply transition can be made while in operation, under full load, and automatically. NG/VPG is WP04GNA standard configuration. With an add-on option, WP04GNA can also support LPG, manual or automatic switching. WEICHAI EMISSION-RELATED INSTALLATION INSTRUCTIONS GET YOUR WEICHAI & AFTERMARKET SERVICE PARTS AT FLYPARTSGUY.COM