Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation

Abstract

Experiments were carried out in a spark-ignition engine fueled with iso--propanol/gasoline blends. Emission characteristics of this engine were investigated experimentally, including gaseous emissions (HC, CO, NOx) and particulate matter emission in term of number and size distributions. The effects of different iso-propanol percentages, loads and exhaust gas re-circulation rates on emissions were analyzed. Results show that the introduction of exhaust gas re-circulation reduces the NOx emission and NOx emission gives the highest value at full load condition. HC and CO emissions present inconspicuous variations at all the loads except the load of 10%. Additionally, HC emission shows a sharp increase for pure propanol when the exhaust gas re-circulation rate is up to 5%, while little variation is observed at lager exhaust gas re-circulation rates. Moreover, the particulate matter number concentration increases monotonically with the increase of load and the decrease of exhaust gas re-circulation rate. There exists a critical spark timing that produces the highest particulate matter number concentration at all the blending ratios.