Spencer Harp

RCCI Operation With PFI of n-Butanol and DI of Biodiesel Compared With DI of Binary Mixtures of n-Butanol and Biodiesel

In this study the Reactive Controlled Combustion Ignition (RCCI) obtained by early port fuel injection (PFI) of n-butanol and direct injection (DI) of biodiesel were compared with in cylinder direct injected binary mixture of n-butanol and biodiesel with the same mass ratio of 3:1 in both fuelling strategies. The combustion and emissions characteristics were investigated at 5 bars IMEP at 1400 rpm. The ignition for DI of n-butanol-biodiesel binary blends showed a delay by approximately 7.5°CAD compared with the PFI case. For the binary mixture, n-butanol-biodiesel, the combustion pressure has decreased by 50% compared to the PFI of butanol. The maximum in cylinder gas temperature decreased by 100K for the n-butanol-biodiesel mixture versus ULSD#2 and has also experienced a 10° CAD delay. The premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC, and a second stage, ATDC for the PFI strategy. Increasing the load to 7.5 bars IMEP, heavy knock occurred for the PFI case. The soot emissions showed a 90% decrease with n-butanol injection PFI and by 98% reduction for DI of n-butanol binary mixture with the biodiesel, while the NOx emissions were reduced by 40% in both cases. The aldehyde emissions exhibited a significant 95% decrease for the n-butanol-biodiesel binary mixture compared with the n-butanol PFI. The mechanical efficiency at 80% and thermal efficiency and 38% were found similar, for both fuelling strategies.The results of this work suggest that the DI of n-butanol-biodiesel binary mixtures is more effective in reducing emissions than PFI of n-butanol combined with DI of biodiesel and also less likely to produce knock.Copyright

RCCI of synthetic kerosene with PFI of N-butanol-combustion and emissions characteristics

In this study, the combustion and emissions characteristics of Reactivity Controlled Compression Ignition (RCCI) obtained by direct injection (DI) of S8 and port fuel injection (PFI) of n-butanol were compared with RCCI of ultra-low sulfur diesel #2 (ULSD#2) and PFI of n-butanol at 6 bar indicated mean effective pressure (IMEP) and 1500 rpm. S8 is a synthetic paraffinic kerosene (C6–C18) developed by Syntroleum and is derived from natural gas. S8 is a Fischer-Tropsch fuel that contains a low aromatic percentage (0.5 vol. %) and has a cetane number of 63 versus 47 of ULSD#2. Baselines of DI conventional diesel combustion (CDC), with 100% ULSD#2 and also DI of S8 were conducted. For both RCCI cases, the mass ratio of DI to PFI was set at 1:1. The ignition delay for the ULSD#2 baseline was found to be 10.9 CAD (1.21 ms) and for S8 was shorter at 10.1 CAD (1.12 ms). In RCCI, the premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC from ignition of ULSD#2 or S8, and a second stage, ATDC from n-butanol combustion. RCCI with n-butanol increased the NOx because the n-butanol contains 21% oxygen, while S8 alone produced 30% less NOx emissions when compared to the ULSD#2 baseline. The RCCI reduced soot by 80–90% (more efficient for S8). However, S8 alone showed a considerable increase in soot emissions compared with ULSD#2. The indicated thermal efficiency was the highest for the ULSD#2 and S8 baseline at 44%. The RCCI strategies showed a decrease in indicated thermal efficiency at 40% ULSD#2-RCCI and 42% and for S8-RCCI, respectively.S8 as a single fuel proved to be a very capable alternative to ULSD#2 in terms of combustion performance nevertheless, exhibited higher soot emissions that have been mitigated with the RCCI strategy without penalty in engine performance.Copyright

Cotton Seed FAME Combustion and Emissions Research in a DI Diesel Engine

This study investigates the combustion characteristics of cotton seed fatty acid methyl esters (FAME), with C100 (100% cotton seed biodiesel) and C20 (20% cotton seed biodiesel, 80% ultra-low sulfur diesel #2), in a direct injection diesel engine and compares the results with ultra-low sulfur diesel #2 (ULSD#2). The dynamic viscosity of C100 was found to meet the American Society for Testing and Materials (ASTM) standard. The lower heating value obtained for C100 was 37.7 MJ/kg, compared to 42.7 MJ/kg for ULSD#2. ULSD#2 and C100 displayed ignition delays of 9.6 crank angle degrees (CAD) and 7 CAD representing 1.14 ms and 0.83 ms respectively and a combustion time of 4ms (35 CAD) at 1400 rpm and 8 bar indicated mean effective pressure (IMEP) (100% load). The apparent heat release of the tested fuels at 8 bar IMEP showed both a premixed and diffusion phase and produced maximum values of 122 and 209 J/CAD for C100 and ULSD#2 respectively, with a decreasing trend occurring with increase in percentage of FAME. The 50% mass burnt (CA50) for 100% biodiesel was found to be 3 CAD advanced, compared with ULSD#2. The maximum total heat flux rates showed a value of 3.2 MW/m2 for ULSD#2 at 8 bar IMEP with a 6% increase observed for C100. Mechanical efficiency of ULSD#2 was 83% and presented a 5.35% decrease for C100, while the overall efficiency was 36% for ULSD#2 and 33% for C100 at 8 bar IMEP. The nitrogen oxides (NOx) for C100 presented an 11% decrease compared with ULSD#2. Unburned hydrocarbons value (UHC) for ULSD#2 was 2.8 g/kWh at 8 bar IMEP, and improved by 18% for C100. The carbon monoxide (CO) emissions for C100 decreased by 6% when compared to ULSD#2 at 3 bar IMEP but were relatively constant at 8 bar IMEP, presenting a value of 0.82 g/kWh for both fuels. The carbon dioxide (CO2) emissions for C100 increased by 1% compared with ULSD#2, at 3 bar IMEP. The soot value for ULSD#2 was 1.5 g/kWh and presented a 42% decrease for C100 at 8 bar IMEP. The results suggest a very good performance of cotton seed biodiesel, even at very high content of 100%, especially on the emissions side that showed decreasing values for regulated and non-regulated species.Copyright

NVH of RCCI With DI ULSD and PFI With 50% N-Butanol

The noise of diesel engines is dependent upon numerous factors such as: load, speed, fuel injection strategies and fuel type, design of the piston, piston-pin and cylinder and their tolerances, bearings, valves and rocker arm clearances, and designs of the manifolds.In this study, engine sound and vibrations analysis have been conducted using two types of fueling and combustion strategies: classical ULSD combustion and the new RCCI with n-butanol injected in the intake manifold. The analyses add to the understanding of the influence of combustion characteristics’ effect on mechanical noise and vibrations throughout the engine’s operating cycle.The sound and vibration signals were both analyzed in the frequency and angle domain spectrum. Overall NVH spectrum from ULSD combustion was compared to that of RCCI with 50% by mass PFI of n-butanol (the 50% remaining ULSD fuel was directly injected).Frequency analyses were performed using the FFT and CPB methods with Bruel & Kjaer’s Pulse sound and vibrations analysis software. Angle domain analyses were performed, referencing 0 CAD as TDC in combustion.The engine tests were conducted at 1500 rpm and 4 bar IMEP. The COV of IMEP for DI ULSD and RCCI were 2.4 and 2.2, respectively. The correlations between sound, three dimensional vibration levels, and timings were found for: pressure gradients from combustion process, intake and exhaust valve actuations and gas exchange, and piston slap on the cylinder liner.The measurements were extracted and analyzed, and the results determined that virtually all the noise and vibration values pertinent to RCCI were lower than those of ULSD classical combustion.Copyright

Indirect Combustion Technology With Renewable Non-Edible Transesterified Oil Feedstock

This investigation focused on the combustion and performance of an indirect injection (IDI) diesel engine powered by a non-edible biodiesel blend, Brassica Carinata. This oilseed has become an attractive non-edible feedstock for biodiesel in the United States, given potential agronomical advantages. A small bore, single cylinder IDI engine was run at 2000 rpm and 5.5 bar indicated mean effective pressure (IMEP) using ultra-low sulfur diesel #2 (ULSD#2) and compared with C50, a 50% Carinata biodiesel-ULSD#2 blend (by mass). The apparent heat release for C50 reached a maximum of 22.04 J/deg which was 6.3 % lower and peaked 1.80 CAD before ULSD#2. The radiation and convection heat fluxes had similar maximum values of 0.62 MW/m2 and 1.34 MW/m2, respectively. The brake specific fuel consumption (BSFC) of C50 was 211.05 g/kWh, which was 9% higher than for ULSD#2. The mechanical efficiency was maintained relatively constant at 55% while the indicated thermal efficiency of the engine reached 59%. Both fuels produced similar nitrogen oxide (NOx) emissions with ULSD#2 and C50 producing 2.29 g/kWh and 2.23 g/kWh, respectively. The results indicate that the IDI engine can optimally work with concentrations up to 50% biodiesel.Copyright

Combustion Performance, Noise, and Vibrations of an IDI Engine Fueled With Carinata Biofuel

The performance of an indirect injection engine fueled with a biodiesel blend was investigated at 2400 rpm and 6 bar IMEP. The single cylinder experimental engine was run using C50 and compared to a ULSD#2 baseline. Brassica carinata oilseed was studied as it can potentially provide improvements for existing fuel infrastructures. Cylinder pressure data for C50 showcased a lower heat release and slightly higher injection pressure due to higher SMD. Brake specific fuel consumption was 6% higher for C50 given the characteristic LHV of biodiesel. Vibrations and sound measurements were analyzed in the frequency and crank angle domain through the Bruel & Kjaer PULSE software platform. Sound pressure correlations were determined according to the piston normal force on the cylinder liner, intake and exhaust valve timing, and operating speed. For both fuels, vibrations parallel to the cylinder axis reached 1.6–2.6 m/s2 in the 40–120 Hz frequency range; noise reached 80–87 dB at frequencies of 1–4 kHz. C50 produced 0.4 g/kWh fewer NOx emissions which correlate to a lower maximum bulk gas temperature and richer air-fuel ratio. The average ringing intensity was 0.05 MW/m2 for both fuels due to a comparable pressure rise rate. When the engine was run with C50, the reference mechanical efficiency of 53% was effectively maintained. This offers validation for further implementation of blended biodiesel fuel in IDI engines.Copyright

Fabrication of Polyacrylonitrile Nanofiber Membranes Functionalized With Metal Organic Framework for CO2 Capturing

Crystalline particles known as Metal Organic Frameworks (MOF’s) are known for their large surface area and high adsorption and storage capacity for CO2 gas. Electrospun nanofibers are considered as ideal substrates for synthesizing the MOF particles on the fiber surface. In this project, Polyacrylonitrile (PAN) and a Cu-based MOF known as HKUST-1 were selected as substrate fibers and adsorbent particles respectively. A precursor solution of PAN polymer hybridized with HKUST-1 particles dissolved in Dimehtylformamide (DMF) is used as the primary component solution for electrospinning. SEM images of the electrospun fibers showed small MOF particles formation into the fiber structure. A secondary solvothermal process of MOF particles growing on the fibers was then executed to increase the amount of MOF particles for effectual gas adsorption. The secondary process consists of multiple growth cycles and SEM images showed uniform distribution of porous MOF particles of 2–3μm in size on the fiber surface. EDS report of the fiber confirmed the presence of MOF particles through identification of characteristic Copper elemental peaks of HKUST-1. Thermogravitmetric analysis (TGA) of HKUST-1 doped PAN fiber displayed 32% of total weight loss between 180°C and 350°C thus proving the as-synthesized MOF particles are thermally stable within the mentioned temperature range. A comparative IR spectroscopic result between the gas-treated and gas-untreated fiber samples showed the presence of characteristic peak in the vicinity of 2300 and 2400cm−1 which corroborates the assertion of adsorption of CO2 on the system. Further step involved is to investigate the gas adsorption capacity of the filter system in an experimental test bench. Non-dispersive Infrared (NDIR) CO2 sensors will be used at the gas inlet and outlet parts to measure the concentration of CO2 and determine the amount of gas uptake by the filter system.Copyright

Design of an Ankle Stiffness Testing and Therapeutic Device

The research objective of this project is to design an ankle stiffness testing and therapeutic device. The hypothesis is that the ankle stiffness of people afflicted with diabetes mellitus (DM) is significantly different from that of healthy subjects. The validation of this hypothesis will allow us to clarify the relationship between ankle stiffness and ulceration or other pathologies. If we can use this objective device to prove that increased stiffness does play a significant role in ulcerations and other pathologies of the foot and ankle, the same device can also be used as a therapeutic device to help reduce ankle stiffness and thus prevent foot ulcers.Copyright