During the first test series, it was found
that FGR had little effect on NOx reduction.
Therefore, part way through the demonstration,
the FGR system was removed. At the
same time, the natural gas injectors were
replaced by high-velocity injectors, which
made greater use of the available natural gas
pressure. Also, the OFA ports were modified
to provide higher jet momentum, air
swirl capability, and velocity control. This
provided improved lateral coverage and turbulence
in mixing with unburned fuel. After
these modifications, the system was referred
to as Second Generation GR-LNB.