Alabama Transportation Institute

Permanent URI for this community

https://ir.ua.edu/handle/123456789/8237

Browse

Browsing Alabama Transportation Institute by Subject "Alternative fuels"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    A comprehensive experimental investigation of low-temperature combustion with thick thermal barrier coatings
    (Pergamon, 2021) Yan, Ziming; Gainey, Brian; Gohn, James; Hariharan, Deivanayagam; Saputo, John; Schmidt, Carl; Caliari, Felipe; Sampath, Sanjay; Lawler, Benjamin; Clemson University; University of Alabama Tuscaloosa; State University of New York (SUNY) System; State University of New York (SUNY) Stony Brook
    Thick thermal barrier coatings (TBCs) have a significant potential to increase thermal efficiency by reducing heat transfer losses. However, in conventional combustion modes, the drawbacks associated with charge heating and higher propensity to knock have outweighed the efficiency benefits. Since the advanced low-temperature combustion (LTC) concepts are fundamentally different from the conventional combustion modes, these penalties do not exist in most of LTCs. The current experimental study shows the feasibility and benefits of thick TBCs with advanced LTC enabled by two different fuels: conventional gasoline and wet ethanol 80 (WE80, i.e., 80% ethanol and 20% water by mass). A total of five pistons were tested, including two metal baselines and three TBCcoated pistons with different thicknesses or surface finishes. A load sweep was conducted with each fuel on each piston within the same constraints. The thick TBCs extends the low load limit by about 15% for both gasoline and WE80 cases. A deterioration of the high load limit was not observed, which implies that the charge heating penalty does not occur in LTCs. The combustion efficiency increased for the thicker TBC by up to 2% points, and the fuel conversion efficiency was increased by up to 4.3%. The gasoline cases experience the largest benefits at low load, while the wet ethanol experiences the largest benefits at mid-to-high load. The intake temperature requirement is successfully reduced by 10-15 K. It is also observed that the dense sealing layer results in a significant improvement to UHC emissions. All of the coated pistons survived the 10-20 h of engine operation with no visual failure. (c) 2021 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item
    Experimental Study of Spark-Ignition Combustion using the Anode Off-Gas from a Solid Oxide Fuel Cell
    (2020) Ran, Zhongnan; Assanis, Dimitris; Hariharan, Deivanayagam; Mamalis, Sotirios; University of Alabama Tuscaloosa
    Hybridizing Solid Oxide Fuel Cells (SOFCs) with internal combustion engines is an attractive solution for power generation at high electrical conversion efficiency while emitting significantly reduced emissions than conventional fossil fueled plants. The gas that exits the anode of an SOFC operating on natural gas is a mixture of H2, CO, CO2, and H2O vapor, which are the products of the fuel reforming and the electrochemical process in the stack. In this study, experiments were conducted on a single-cylinder, spark-ignited Cooperative Fuel Research Engine using the anode off-gas as the fuel, at compression ratio of 11:1 and 13:1, engine speed of 1200 rev/min and intake pressure of 75 kPa, to investigate the combustion characteristics and emissions formation. A comparison was drawn with combustion with Compressed Natural Gas (CNG) at the same engine operating conditions. The experimental results revealed that the anode off-gas can be used as a potential alternative fuel for spark-ignition combustion, and an engine can be used to provide additional power to a hybrid SOFC-engine system. Combustion with the anode off-gas resulted in similar net indicated efficiency with CNG at CR of 13:1, but with negligible NOx emissions and zero total hydrocarbon emissions. However, combustion with the anode off-gas resulted in lower volumetric efficiency and lower load than CNG as a result of high levels of dilution in the off-gas, which greatly reduces the lower heating value of the fuel. This study demonstrated the feasibility of using the SOFC anode-off gas as a potential fuel for spark-ignition engines with good fuel conversion efficiency and minimal NOx and THC emissions.