HSDI Diesel Engine Optimisation for GTL Diesel Fuel

A Mercedes E320 CDI vehicle has been modified for more optimal operation on Gas-To-Liquids (GTL) diesel fuel, in order to demonstrate the extent of exhaust emission reductions which are enabled by the properties of this fuel. The engine hardware changes employed comprised the fitment of re-specified fuel injectors and the reduction of the compression ratio from 18:1 to 15:1, as well as a re-optimisation of the software calibration. The demonstration vehicle has achieved a NOx emission of less that 0.08 g/km in the NEDC test cycle, while all other regulated emissions still meet the Euro 4 limits, as well as those currently proposed for Euro 5. CO₂ emissions and fuel consumption, were not degraded with the optimised engine. This was achieved whilst employing only cost-neutral engine modifications, and with the standard vehicle exhaust system (oxidation catalyst and diesel particulate filter) fitted. The project outcome has demonstrated that GTL diesel fuel can be an enabler for cost efficient reductions in exhaust emissions, which can be implemented without compromising engine efficiency or performance.