Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation
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, NO x ) 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 NO x
... duces the NO x emission and NO x 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.