Biodiesel is promising alternative fuel to run the automotive engine but idling is the
main problem to run the vehicles in a big city. Vehicles running with idling condition cause
higher fuel supply and higher emission level due to being having fuel residues in the exhaust.
The purpose of this study is to evaluate the impact of alcohol additive on fuel consumption and
emissions parameters under idling conditions when a multicylinder diesel engine operates with
the diesel-biodiesel blend. The study found that using 5% butanol as an additive with B5 (5%
Palm biodiesel + 95% diesel) blends fuel lowers brake specific fuel consumption and CO
emissions by 38% and 20% respectively. But the addition of butanol increases NOx and CO2
emissions. Based on the result it can be said that 5% butanol can be used in a diesel engine
with B5 without any engine modifications to tackle the idling problem.