21
ADJUSTABLE PARAMETERS
This engine has been certified by the US EPA to operate on pipeline quality commercial Natural Gas fuel
as well as commercial LPG/propane.
The Fuel System is non-adjustable and it can compensate for changes within commercial fuels at
different locations in the US. Customers can use a fuel switch (PG Switch in Figure 21) to switch
between NG and LPG operation. The default setting is for NG,
the other position “PG” is for fuels with
LPG/VPG (short Engine Interface Pin G & R).
Figure 19 Fuel Switch for Different Fuels
WARNING: ADJUSTMENTS MADE TO THE FUEL DELIVERY SYSTEM WILL INFLUENCE THE TAILPIPE
EXHAUST EMISSIONS.
IT IS THE OWNER/OPERATOR’S RESPONSIBILITY TO TEST THE SPECIFIC FUEL TYPE
AT EACH SITE OF INSTALLATION AND DETERMINE THE CORRECT FUEL SYSTEM SETTINGS.
Fuel Pressure
Fuel Pressure need to be checked for the first start as in the Table 1
Table 1 EPR inlet pressure specification
Maximum EPR Rated Pressure
kPa
6.9
Maximum Running pressure to Electronic Pressure Regulator (EPR)
kPa
2.7
FUEL SYSTEM DIAGNOSTIC
FUEL SYSTEM DESCRIPTION
The Engine Control Module (ECM) receives information from various engine sensors in order to control
the operation of the Integrated Electronic Pressure Regulator (EPR) and Shut-Off Valve. The Shut-Off
Valve solenoid prevents fuel flow unless the engine is cranking or running.
At Key ON, the DEPR valve receives a two (2) second prime pulse from the ECM, allowing time
for the fuel to flow through the fuel filter and fuel lines to the IEPR.
The fuel is then to the mixer. Engine cranking generates vacuum which provided lift for the mixer air
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