Open Access

ARTICLE

Influence of Ethanol-Diesel Blends on Pollutant Emissions and Engine Behavior in Compression Ignition Engines

Shaymaa H. Abdulmalek^1,*, Atheer F. Mahmood², Ali R. Mahdi³, Miqdam T. Chaichan^4,5, Hasanain A. Abdul Wahhab³
1 Electromechanical Engineering Department, University of Samarra, Samarra, Iraq
2 Oil and Gas Engineering College, University of Technology—Iraq, Baghdad, Iraq
3 Training and Workshop Center, University of Technology—Iraq, Baghdad, Iraq
4 Energy and Renewable Energies Technology Center, University of Technology—Iraq, Baghdad, Iraq
5 Faculty of Engineering, Sohar University, Sohar, Oman
* Corresponding Author: Shaymaa H. Abdulmalek. Email:
(This article belongs to the Special Issue: Sustainability Through Advancements in Energy Processes, Systems, Materials, and Policies)

Energy Engineering https://doi.org/10.32604/ee.2026.086929

Received 08 June 2026; Accepted 08 July 2026; Published online 10 September 2026

Abstract

In response to the current energy crisis and escalating concerns about pollution, research efforts have increasingly focused on reducing fuel consumption and minimizing the emission of toxic substances from combustion processes. This has led to the exploration of non-petroleum, renewable, sustainable, and environmentally friendly fuels, unlike conventional energy sources such as natural gas, oil, and coal, which are non-renewable. Renewable and sustainable resources can be used to produce alcohol, such as ethanol. This study compares the combustion and emission characteristics of neat diesel fuel with those of ethanol-diesel fuel blends. Experiments were conducted under steady-state conditions using a four-cylinder, direct-injection diesel engine operating at various load and 1500 rpm. The results showed that blending ethanol with Diesel at 10%, 15%, 20%, and 25% significantly reduced carbon monoxide emissions by 10.06%, 20.89%, 40.34%, and 49.13%, respectively. For unburned hydrocarbons (HC), the reduction rates were 6.3%, 14.86%, 19.70%, and 28.62%, while the nitrogen oxides (NOx) reduction rates were 19.73%, 10.53%, 17.65%, and 12.69%, respectively, compared to Diesel. However, due to ethanol’s lower calorific value, ethanol-diesel blends increased specific fuel consumption by 12%, 8.9%, 5.4%, and 2%, respectively, when the engine was operated at the optimal injection timing for each fuel type. When the engine was operated at the optimal diesel timing, the BSFC was reduced by 2%, 5.4%, 8.9% and 12%, compared to diesel, respectively. These results suggest that ethanol can be efficiently blended with diesel and used in existing engines without modifications.

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Keywords

Compression ignition engines; cetane number; diesel-ethanol solution; oxygenate; noise

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