Eco-efficient high-performance diesel operation with biodiesel–butanol blends optimized by soapnut-based bio-nano additives

¹ Department of Mechanical Engineering, Jawaharlal Nehru Technological University Anantapur, Ananthapuramu, Andhra Pradesh, India
² Department of Mechanical Engineering, K.S.R.M. College of Engineering, Kadapa, Affiliated to Jawaharlal Nehru Technological University Anantapur, Ananthapuramu, Andhra Pradesh, India
³ Department of Mechanical Engineering, JNTUA College of Engineering, Ananthapuramu, Constituent college of Jawaharlal Nehru Technological University Anantapur, Ananthapuramu, Andhra Pradesh, India

^* Corresponding author: alagalaharikrishna@gmail.com

Published online: 7 January 2026

Abstract

This study looks at how well a diesel-fueled compression ignition engine works and how much pollution it produces. It uses a 20% Chlorella vulgaris biodiesel blend (B20), a 5% butanol (B20+D75BU5) blend, and soapnut bio-nano particles (SNPs) at 30, 60, and 90 ppm. Adding butanol made the fuel more volatile and increased the amount of oxygen in it. SNPs, which are biodegradable catalytic agents, increased micro- turbulence and full oxidation. The Efficiency which is in brake-thermal has recorded maximum peak (B20+D75BU5+60 ppm SNP) i.e.33.6 percentage. At the maximum load the least BSFC i.e.0.137 kg/kWh has recorded. The reduction of CO and HC emissions by about 33 plus 58%, was accompanied by a small increase in CO₂, which is a clear indication of a more complete combustion. It has been observed that, there is a significant improvement in the NOx, since high temparatures in cylinder, whereas FSN was reduced by up to 23%, which means that the particles were being effectively suppressed. SNPs are advantageous over metal oxide nanoparticles in that they decompose naturally, are less toxic, and have better dispersion characteristics. Thus, there is less wear on engines and less damage to the environment. B20+D75BU5+60 ppm SNP blend was identified as the optimal blend as it enhanced efficiency, reduced fuel consumption, and controlled emissions without the need for engine modification. This is a clear indication that bio-nano additives can be utilized in the development of sustainable high-performance biodiesel-diesel applications.