Analysis of performance, emission, combustion and endoscopic visualization of micro-arc oxidation piston coated SI engine fuelled with low carbon biofuel blends

Abstract

The low carbon biofuel (pine oil) derived from the pine tree is endowed with enhanced fuel properties with good octane rating and can be used for SI engine applications. In order to operate pine oil blends with improved fuel efficiency, engine design modification is required. This work investigates the change reflected on the engine characteristics of the port fuelled SI engine due to a thin thermal barrier coating layer formed on the piston crown using the Micro-arc oxidation technique. Furthermore, an endoscopic visualization technique was adopted to compare the combustion flames of uncoated and coated piston engines fuelled with pine oil blends. The coated piston engine fuelled by pine oil blends displayed improved peak in-cylinder pressure and heat release rate. Among the pine oil blends, P20 (20% pine oil + 80% gasoline) blend showed superior engine characteristics at all engine load conditions. The brake thermal efficiency of the coated piston engine fuelled with the P20 blend was improved by 1.8% compared to the uncoated piston fuelled with gasoline. With the P20 blend, the CO, HC emissions were decreased by 8% and 14% respectively and NO emission was increased by 19% for coated piston when compared to gasoline with an uncoated piston engine.