Regular Article

Effects of ethanol addition to diesel–biodiesel blends on the CI engine characteristics

¹ Mechanical Modelling, Energy & Materials, National School of Engineers, Gabes University, Zrig, 6029 Gabes, Tunisia
² College of Engineering Technology, University of Doha for Science and Technology, Doha 24449, Qatar
³ Faculty of Engineering, Environment and Computing, Coventry University, Coventry CV1 2JH, UK
⁴ Mechanical Engineering Department, Engineering Faculty, Esentepe Campus, Sakarya University, Sakarya 54187, Turkey
⁵ Teamsan Co., Technology Development Zones, Sakarya University, Sakarya 54187, Turkey

^* Corresponding author: ridha.ennetta@issig.rnu.tn

Received: 17 May 2023
Accepted: 4 May 2024

Abstract

This research work investigates the effects of adding ethanol to biodiesel–diesel blends on the performance and emissions of a single-cylinder, four-stroke, air-cooled compression-ignition engine. The engine was half-loaded within a speed range of 1000–2500 rpm. Four different fuel blends are considered: B0 (no biodiesel or ethanol), B10 (10% biodiesel), B10E2.5 (10% biodiesel with 2.5% ethanol), and B10E5 (10% biodiesel with 5% ethanol). The findings show that adding biodiesel slightly affects the engine power at low and medium speeds but increases power by approximately 6% at high speeds. Ethanol addition has a more significant impact, with an increase in engine power of 16% at 1700 rpm and 13% at 2500 rpm for 2.5% and 5% ethanol blends, respectively. All blends show an increase in brake mean effective pressure (BMEP) compared to B0, with the maximum enhancement observed in B10 with an average increase of 13% across all speeds. Specific fuel consumption is reduced with both biodiesel and ethanol addition, with a slight advantage for biodiesel, particularly at low and medium speeds. Thermal efficiency shows a reverse behaviour, with a small negative impact of ethanol addition. Biodiesel addition significantly increases carbon monoxide (CO) emissions, reaching an average of 190% across all speeds. However, adding ethanol helps mitigate this increase, especially at low and medium speeds, with an average decrease of 32% for a 2.5% ethanol blend compared to B0. Carbon dioxide (CO₂) and nitrogen oxides (NO_x) emissions are reduced with biodiesel addition and further reduced with ethanol addition. Overall, CO₂ and NO_x emissions are reduced with both biodiesel and ethanol addition.