Use of a paraffinic gasoil

A method for reducing build up of deposits in a high-pressure Exhaust Gas Recirculation (EGR) system of a compression ignition internal combustion engine, the method comprising the steps of:

• providing a compression ignition internal combustion engine having a high-pressure EGR system and a particulate filter, wherein the particulate filter is positioned downstream of the high pressure EGR;
• introducing into the engine a diesel fuel composition comprising:
• a paraffinic gasoil present at a level of from 50% v/v to 100% v/v, based on the total diesel fuel composition,
• wherein the paraffinic gasoil is selected from a Fischer-Tropsch derived gasoil comprising no more than 3% w/w of cycloparaffins, by weight of the Fischer-Tropsch derived gasoil and having a kinematic viscosity in a range from 2.0 to 5.0 mm2/s at 40° C., a density in a range from 0.775 to 0.785 g/cm3, an aromatics content below 0.1% w/w and a cetane number from 70 to 77, and a hydrotreated vegetable oil (HVO) derived gasoil, and mixtures thereof;
• and
• combusting the diesel fuel composition;
• wherein deposits in the EGR system after the fuel composition has been combusted in the compression ignition internal combustion engine for 24 hours continuously, at 2500 rpm and 5 kW test condition and at an engine coolant temperature controlled to 37° C., are reduced by 10% or more compared to the build up of deposits in an EGR system caused by an analogous fuel formulation which does not contain a paraffinic gasoil.