Oxygenated fuel components such as the alcohols of 1-butanol and ethanol are well-known for their
potential to improve engine combustion and PM emissions, and these particular fuels are receiving ever
greater attention due to their renewable nature giving them great CO2 emission reduction potential. This
paper investigates the effect of compression ratio and fuel properties on combustion, gaseous emissions
and PM emissions of an experimental single-cylinder direct injection spark ignition (DISI) engine. The
tests were carried out at an engine load of 8.5 bar, at various compression ratios between 10.7 and
11.5, with Bu20 (20%vol 1-butanol in gasoline) and E20 (20%vol ethanol in gasoline) fuel blends along
with a reference fuel of gasoline. The results show that 1-butanol and ethanol addition to gasoline is
effective to advance the MFB50 point and shorten the combustion duration. 1-butanol addition to gasoline
is effective to reduce PM number emissions, while NOx reduction is the main benefit of ethanol addition.
It is concluded that synergies between compression ratio and alcohol addition to gasoline enable to
simultaneously control gaseous and particulate matter emissions while improving fuel economy with
respect to standard gasoline combustion.