The effect of fuel cetane improver on diesel pollutant emissions

A base fuel having a cetane number of 40.2 was split into nine batches. To eight of these batches, varying quantities of ignition improver were added, resulting in cetane numbers up to 62, The base full and each of the blends with ignition improver were used in a co-operative fuel research (CFR) diesel engine, and the exhaust emissions of NOx unburnt hydrocarbons (UHC) and smoke were measured, to ascertain the effect of varying cetane number on emissions when the basic chemical structure and physical properties of the fuel were almost unaltered. The results showed that the exhaust NOx progressively decreased with increasing cetane number, due to the reduction in ignition delay and amount of premixed fuel burnt, Similarly, the UHC decreased. However, the smoke increased due to the reduction in the amount of relatively smoke-free premixed fuel burnt.