Original: https://doi.org/10.1080/14786451.2026.2614788
Waste cooking oil (WCO) can be used as a renewable fuel for diesel engines. However, it is thicker (more viscous) than regular diesel, which makes it difficult to use directly in engines.
To solve this problem, higher alcohols like n-octanol can be added. Adding n-octanol improves the fuel’s flow and combustion properties, and it does not require a chemical conversion process (such as transesterification).
In this study, researchers examined how two factors affect engine performance and emissions:
- Engine load (how hard the engine is working)
- Amount of n-octanol in the fuel blend
They tested different mixtures of diesel, WCO, and n-octanol in a 10-kW stationary diesel engine. They used a structured experimental method and statistical modeling to analyze the results. Their prediction models were accurate, with errors less than ±8%.
The best fuel mixture was:
- 50% diesel (D50)
- 30% waste cooking oil (W30)
- 20% n-octanol (O20)
At 65% engine load, this blend gave the best overall results. Compared to regular diesel fuel, it:
- Reduced CO (carbon monoxide) by 5.70%
- Reduced NOX (nitrogen oxides) by 33.56%
- Reduced HC (unburned hydrocarbons) by 12.24%
- Reduced smoke by 22.85%
- Maintained similar engine efficiency (BTE)
Overall, the study shows that adding alcohol to waste cooking oil is a practical way to make diesel engines run cleaner while keeping good performance.