Performance and emission characteristics of Baobab (Adansonia Digitata) bio-lubricant in four stroke spark ignition engine

Abstract

Over the years, the growing interest for bio-based alternatives to mineral products (i.e. fuel and lubricant) to save energy and improve environmental friendliness has become one of the most researched topics. According to world meteorological organization (WMO), Concentration of carbon dioxide (CO₂) reached 420.23 parts per million in April, 2022. In this research, the extract from baobab nuts was purified, degummed and epoxidized to form Bio-lubricant. The physicochemical properties of the formed bio-lubricants were determined and are within the index of American Society for Testing and Materials (ASTM). The Fourier Transform Infrared (FTIR) at different temperatures and Gas Chromatography Mass Spectroscopy (GC-MS) with two different acids were conducted on the products. The results depicted minimal changes with repeated oxidation at higher temperature and different acids respectively. A four-stroke spark ignition engine at three different speeds was used to validate the bio-lubricant by compared with SAE40 performances. Four engine parameters considered: specific fuel consumption (SFC), brake thermal efficiency, brake power and brake mean effective pressure. The bio-lubricant maintained a low values trend for the four parameters at engine speeds of 2000rpm, 2500rpm and 3000rpm with exception of brake thermal efficiency that depicts high value of 56% at both 2000rpm and 3000rpm. The SI engine lubricated with SAE40 has higher CO, HC and CO2 emissions.