Term of Award

Spring 2022

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

An investigation was conducted on the optimal engine parameters for facilitating lower NOX and soot emissions of PCCI combustion with either ethanol or n-butanol. The PFI fuels selected were tested at loads of 3, 4, and 5 Bar IMEP for a total of 28 total combustion tests with variations made to the EGR% and boost pressure for each test in order to find the optimal emissions strategy. A Mie-scattering spray fuel analysis was also conducted on the three fuels to gain insight on their influence on combustion/emissions characteristics. It was found that ethanol had a greater average Sauter Mean Diameter than n-butanol by 5 μm. This indicated that if the intake temperature is not sufficiently high, ethanol may not form a complete homogenous air-fuel mixture compared to n-butanol. Although ethanol had a lower reactivity than n-butanol it was found that the PPRR and subsequent AHRR was dramatically increased at loads of 4 and 5 bar IMEP. At 4 bar IMEP, PCCI with ethanol had an increased PPRR of 39% to PCCI with n-butanol and an increase of 39.67% for max AHRR. At 5 bar IMEP, PCCI with ethanol had an increased PPRR from PCCI with n-butanol of 38.94% and an increase of max AHRR of 50.98%. In concerns to the emissions, it was found that PCCI with n-butanol had greater reductions of NOX emissions than PCCI with ethanol while ethanol was found to greatly reduce soot emissions. At a load of 5 bar IMEP, PCCI with n-butanol had a simultaneous reduction of NOX and soot emissions of 53.2% and 36.7% respectively from CDC while PCCI with ethanol had emissions reductions of 21.3% and 72.28% respectively from CDC. In addition to this, the environmental impact of PCCI with either ethanol or n-butanol was shown to be considerably reduced by as much as 58.9% as indicated by the lower renewable carbon index. PCCI with n-butanol if incorporated at higher loads and a proper EGR/boost strategy, is a greater method of choice for reducing both NOX and soot emissions while reducing the environmental impact.

Research Data and Supplementary Material

No

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