3
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 3 Way
Catalyst. Stoichiometric engine operation ensures that there is the precise amount of air delivered to
completely burn all the fuel. The stoichiometric Air Fuel Ratio (AFR) for natural gas is 17.2:1 and for
propane is 15.5:1. With rich burn there is slightly less air delivered relative to fuel resulting in slightly
less fuel efficiency, more power and a cooler combustion process.
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: WP10GNA 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 WP10GNA 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
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E480
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