## 4 Conclusions  
2-ethylhexyl nitrate (EHN) has proven to be an effective solvent for reducing the viscosity of straight vegetable oils (SVOs), with blends of 65% EHN for sunflower oil and 75% for castor oil meeting viscosity requirements. Additionally, the combustion properties of these blends are similar to those of fossil diesel, positioning EHN as a promising candidate in a new category of low-viscosity, high-caten (LVHC) solvents. Unlike traditional low-viscosity, low-caten (LVLC) solvents, which tend to lower cetane numbers, EHN enhances both biofuel performance and diesel engine compatibility. A notable advantage of LVHC solvents is their higher calorie value, maintaining power output levels similar to fossil diesel. By increasing the cetane number, EHN also improves combustion efficiency, reducing ignition delay and ensuring stable emissions with only minor NOx increases.  
Significantly, the pure Bio100 CO blend achieved a notable 12.6% improvement in power output compared to fossil diesel, while Bio100 SO showed an 8% increase, demonstrating both blends as viable substitutes for fossil diesel. Among the triple blends, Bio60 SO and Bio60 CO were the most efficient, achieving the highest power outputs and enabling substantial fossil diesel reduction. Specifically, Bio60 SO also achieved significant reductions in soot and CO emissions by 30% and 80%, respectively, compared to fossil diesel, while maintaining comparable NOx emissions. These findings suggest that both pure biofuels and triple blends can serve as renewable and high-performance alternatives to fossil diesel. The Bio100 CO blend, in particular, shows potential for reduced fuel consumption, underscoring EHN and other renewable nitrocompounds as promising LVHC solvents for sustainable diesel engine applications. To further advance the potential of LVHC solvents like EHN, future research could explore other renewable nitrocompounds and LVHC solvents to broaden the spectrum of biofuel compatibility. Additionally, long-term studies on engine performance and maintenance with these biofuel blends are essential to ensure durability and reliability, providing comprehensive insights into their practical applications in various engine types and conditions.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app142411968/s1](https://www.mdpi.com/article/10.3390/app142411968/s1)]([https://www.mdpi.com/article/10.3390/app142411968/s1](https://www.mdpi.com/article/10.3390/app142411968/s1)), Table S1: Technical description of the Diesel Engine Electric Generator Set: Table S2: Measurement accuracy of the different parameters.  
R.E.: Conceptualization, Supervision, Writing-review and editing, Investigation; F.J.L.-T.: Investigation, Writing-original draft, Writing--review and editing; V.M.: Investigation, Formal Analysis; A.A.R.: Formal Analysis; F.M.B.: Funding acquisition, Project administration, formal analysis; D.L.: Formal Analysis, Conceptualization, Supervision, writing--review and editing. All authors have read and agreed to the published version of the manuscript.  
The authors are thankful to MCIN/AEI/10.13039/501100011033 (project PID2022/142275 OB-I00), MCIN/AEI/10.13039/501100011033 and Union Europea \"NextGenerationEU/PRTR\" (project TED2021/132224B-I00), and F.J.L.T. is thankful to the program FEDER-Andalucia 2021-2027, Junta de Andalucia (Project PP2F_L1_21).  
Not Applicable.  
Data Availability Statement: Data are contained within the article.  
The authors are thankful for the technical assistance of the staff at the Central Service for Research Support (SCAI) and that provided by the Instituto Quimico para la Energia y el Medioambiente (IQUEMA).