GTL (Gas-To-Liquid) fuel is well known to improve tailpipe
emissions when fuelling a conventional diesel vehicle, that is, one
optimized to conventional fuel. This investigation assesses the
additional potential for GTL fuel in a GTL-dedicated vehicle.
This potential for GTL fuel was quantified in an EU 4 6-cylinder
serial production engine. In the first stage, a comparison of
engine performance was made of GTL fuel against conventional
diesel, using identical engine calibrations. Next, adaptations
enabled the full potential of GTL fuel within a dedicated
calibration to be assessed. For this stage, two optimization goals
were investigated: - Minimization of NOx emissions and -
Minimization of fuel consumption.
For each optimization the boundary condition was that emissions
should be within the EU5 level. An additional constraint on the
latter strategy required noise levels to remain within the baseline
reference.
Optimizing the calibration for GTL fuel led to further
substantial reductions of regulated emissions, i.e., achieving EU 5
levels with a former EU 4 vehicle, as well as significantly reduced
exhaust CO₂ emissions.
The use of GTL fuel in combination with a dedicated calibration
already achieves a significant benefit, even before consideration
of potential hardware modifications. This would allow an improved
emissions level for compliance with required local legislation.