EFFECT OF CARBON NANOTUBE ADDITIVES ON DIESEL ENGINE PERFORMANCE, COMBUSTION, AND EMISSIONS UNDER VARIABLE EGR CONDITIONS
Heat Transfer Research, cilt.57, sa.8, ss.63-98, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 57 Sayı: 8
- Basım Tarihi: 2026
- Doi Numarası: 10.1615/heattransres.2025061352
- Dergi Adı: Heat Transfer Research
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Sayfa Sayıları: ss.63-98
- Anahtar Kelimeler: carbon nanotubes (SWCNT and MWCNT), combustion characteristics, diesel engine performance, exhaust emissions, exhaust gas recirculation
- Bilecik Şeyh Edebali Üniversitesi Adresli: Evet
Özet
This study evaluates the effects of single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT) as diesel fuel additives on engine performance, combustion characteristics, and emissions under varying exhaust gas recirculation (EGR) rates (0%, 10%, and 20%) at a constant engine speed of 1800 rpm. The main purpose of the study is to determine the optimal carbon nanotube (CNT) type and concentration that enhance combustion efficiency while reducing exhaust emissions under different EGR conditions. SWCNT and MWCNT were blended with diesel at 25 ppm and 50 ppm concentrations to analyze their catalytic performance across different engine loads. All experiments were performed on a single-cylinder, four-stroke, air-cooled, direct-injection diesel engine (ANTOR 3LD510) with a displacement of 510 cm³ and a compression ratio of 17.5:1, operating steadily at 1800 rpm. The results showed that MWCNT at 25 ppm achieved the highest cylinder pressure of 71.14 bar at 100% load with 0% EGR, compared to 73.55 bar for diesel. Cumulative heat release (CHR) increased significantly with MWCNT at 25 ppm, delivering a maximum of 41.48 MJ at 100% load under 20% EGR, compared to 39.97 MJ for diesel. Similarly, MWCNT at 25 ppm achieved the highest heat release rate (HRR) of 90 J/°CA, representing a marked improvement over diesel. In terms of engine performance, MWCNT at 25 ppm reduced brake specific fuel consumption (BSFC) to 252.81 g/kWh at 100% load under 0% EGR, compared to 279.85 g/kWh for diesel. Thermal efficiency improved to 37.38% at 100% load with 20% EGR for MWCNT at 25 ppm, compared to 34.42% for diesel. These results underscore the superior energy conversion efficiency achieved with MWCNT additives. Emission analysis revealed that MWCNT at 25 ppm reduced CO emissions to 0.03% and HC emissions to 11 ppm at 50% load under 10% EGR, compared to 0.034% CO and 18 ppm HC for diesel. Soot emissions were reduced to 0.02 mg/m³ under 20% EGR at 100% load, compared to 0.21 mg/m³ for diesel. However, NOx emissions increased to 1104 ppm under 0% EGR at 100% load for MWCNT at 25 ppm, compared to 1274 ppm for diesel, with reductions observed as EGR rates increased. This study concludes that MWCNT at 25 ppm is the most effective additive for enhancing engine performance and reducing emissions. These findings highlight its potential for optimizing combustion efficiency and meeting stringent emission regulations in diesel engines.