Term of Award

Summer 2024

Degree Name

Master of Science, Mechanical Engineering

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Mechanical Engineering

Committee Chair

Valentin Soloiu

Committee Member 1

Marcel Ilie

Committee Member 2

Mosfequr Rahman

Abstract

As there is increasing concern over emissions of traditional fossil fuels, as well as the future of continued reliance on this dwindling resource, it is becoming increasingly evident that alternative fuels are a necessity. This research investigates the use of a Fischer-Tropsch fuel from natural gas feedstocks, S8, in an internal combustion research engine with a common rail fuel injection system. This synthetic kerosene fuel has a high DCN of 62, indicating high affinity to autoignition compared to conventional pump diesel (ULSD) at 48 DCN. However, due to the process by which it is produced, this fuel lacks the necessary lubrication qualities needed to be a proper substitute for ULSD. To mitigate this, Methyl Oleate, a biodiesel compound, was blended with S8 at 3% by mass, resulting in a blend with significantly improved lubricity while still maintaining the parameters that make S8 a desirable fuel for use in an IC engine. The high DCN contributed to a short Ignition Delay (ID) for the S8 + 3% Methyl Oleate blend which was observed both in the Constant Volume Combustion Chamber (CVCC) and in the instrumented research engine. In the engine, the short ID combined with the superior vaporization rate and spray quality resulted in a smaller premixed combustion event and more mixing controlled combustion, which resulted in smoother engine operation. Low Temperature Heat Release (LTHR) analysis of this fuel further solidified these findings. In conventional engine operation, this fuel blend resulted in lower NOx and soot emissions compared with ULSD. Furthermore, use of boost pressure, Exhaust Gas Recirculation (EGR), and Port Fuel Injection (PFI) of n-butanol was investigated as additional means to reduce emissions. PFI of n-butanol (a renewable alcohol capable of production from biomass) resulted in significant reduction in soot, at the cost of increased NOx. Combination with boost pressure reduced the amount of premixed combustion and improved NOx emissions. The overall results indicate that S8 with 3% Methyl Oleate as a lubricity improver can be a potential replacement for ULSD in IC engine operation.

Research Data and Supplementary Material

No

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