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In this study, Premixed Charge Compression Ignition (PCCI) was investigated with alternative fuels, S8 and n-butanol. The S8 fuel is a Fischer Tropsch (FT) synthetic paraffinic kerosene (SPK) produced from natural gas. PCCI was achieved with a dual-fuel combustion incorporating 65% (by mass) port fuel injection (PFI) of n-butanol and 35% (by mass) direct injection (DI) of S8 with 35% exhaust gas recirculation. The experiments were conducted at 1500 rpm and varied loads of 1-5 bar brake mean effective pressure (BMEP). The PCCI tests were compared to an ultra-low sulfur diesel no. 2 (ULSD#2) baseline in order to determine how the alternative fuels effects combustion, emissions, and efficiencies. At 3 and 5 bar BMEP, the heat release in the PCCI mode exhibited two regions of high temperature heat release, one occurring near top dead center (TDC) and corresponds to the ignition of S8 (CN 62), and a second stage occurring ATDC from n-butanol combustion (CN 28).

Alternative fuels are sought after because they produce lower emissions and sometimes, they have feedstock and production advantages over fossil fuels, but their wear effects on engine components are largely unknown. In this study, the lubricity properties of a Fischer-Tropsch Gas-to-Liquid alternative fuel (Synthetic Paraffinic Kerosene-S8) and of Jet-A fuel were investigated and compared to those of Ultra Low Sulphur Diesel (ULSD). A pin-on-disk tribometer was employed to test wear and friction for a material pair of an AISI 316 steel ball on an AISI 1018 steel disk when lubricated by the fuels in this research work. Advanced digital microscopy was used to compare the wear patterns of the disks. Viscosity and density analysis of the tested fluids were also carried out. Tribometry for the fuel showed that S8 fell between Jet-A and ULSD when friction force was calculated and showed higher wear over time and after each test when compared to that of Jet-A and ULSD.

In order to advance the current research engine to operate in advanced combustion modes such as reactivity controlled compression ignition RCCI a diesel common rail fuel injection system for the experimental research engine has been designed and developed through testing the hydraulic, electrical and electronics, mechanical subcomponents, and the controls strategies. This study presents the process taken based on the verification and validation model of design and development for the fuel injection system incorporating hardware-in-the-loop (HIL) testing prior to engine operation and subsequent engine validation. Software verification was completed through signal converting circuits to confirm precise injection timing and to test the system in a mean effective model to incorporate a PI speed controller along with consistent rail pressure.

This study evaluates the combustion and emissions characteristics of methyl oleate (C₁₉H₃₆O₂ CAS# 112-62) produced by transesterification from oleic acid, one of the main fatty acid components of biodiesel. The ignition delay of ultra-low sulfur diesel#2 (ULSD) and its blends with methyl oleate (O20-O50), varied between 6.5-9.7 CAD, depending on speed, at constant load of 8 bar imep (100% load). The CN was 47 for ULSD and increased up to 51 for O50, which resulted in the start of combustion's premixed phase being advanced by about 2 CAD while reducing the maximum apparent heat release of about 30%. The combustion duration varied in the range of about 56-67 CAD and the maximum total heat flux rate, presented values from 4.2 to 5.5 MW/m₂, which correlate well with the increase of the convection flux because of the speed increase. The maximum cycle temperature was in the range of 2500K for the speeds from 1200 to 1800 rpm for both fuels.

With the growing prices of fossil fuels and the concerns of global warming, the need to seek alternative fuels in the transportation sector is rapidly gaining momentum. This need of change has lead researchers to look beyond the typical alternative fuels for diesel engines and focus on Fatty Acids Methyl Esters (FAME), due to their high calorific value, widespread availability, and relative low cost. The authors investigated the injection and combustion of poultry fat FAME 20-50% by weight in diesel no. 2 mixtures. The dynamic viscosity of the FAME-diesel mixture has been investigated between 25-45°C and ranged from 3-5cSt increasing in correlation with the amount of FAME and lowered by the temperature increase. The new fuel containing up to 50% poultry fat FAME by weight in diesel fuel (B-50) has been injected by a piston-plunger type pump injection system. The injector had a 1x0.200 mm nozzle with a pintle tip needle and the injection pressure was 147 bar.

The Cottonseed biodiesel combustion, sound and vibrations have been evaluated in a medium duty single cylinder DI engine (1.1L/cyl) by comparison with s ULSD#2 reference values. The engine was supercharged and had 20% EGR and all tests were conducted at 1400 rpm and at 4 bar BMEP load. Cylinder pressure was determined using a Kistler piezoelectric transducer. Combustion pressures peaked at 76 bar for both fuels. Ignition delay for CS100 decreased by 0.16 ms when compared to the ULSD#2 baseline. This would lead to a 23% lower peak heat release rate when operating CS100. The pressure rise rate for CS100 was 20% lower than ULSD#2, which related to the reduced ringing intensity for the biodiesel. The sound and vibrations were measured using a B&K condenser type multi-field microphone, and a tri-axial, piezoelectric accelerometer. All noise & vibration signals were analyzed with CPB and FFT Analysis, and Crank Angle Domain Analysis with B&K Pulse Platform software.

The authors investigated the injection and combustion characteristics of a methyl oleate (Methyl 9(Z)-octadecenoate C19H36O2; Mw 296.495), in blends with diesel No. 2 of 20-50% (wt./wt.) in order to evaluate the possibility of using it as an additive to full-bodied biodiesel for performance improvement. The FAME test fuel has been injected in an experimental single-cylinder separate combustion chamber engine with 77 mm bore, with a compression ratio of 23.5:1 at a pressure of 147 bars that proved capable of atomizing the higher viscosity fuel. The diesel fuel was blended with Methyl Oleate up to 50%, (O50) and the mixtures have shown favorable ignition characteristics, with the ignition delay of about 1.03 ms for petroleum diesel (D100) and slightly decreased for O50 at 2000 rpm with about 1% or 0.01 ms.

This paper investigates the performance of an indirect injection (IDI) diesel engine fueled with Bu25, 75% ultra-low sulfur diesel (ULSD#2) blended with 25% n-butanol by mass. N-butanol, derivable from biomass feedstock, was used given its availability as an alternative fuel that can supplement the existing limited fossil fuel supply. Combustion and emissions were investigated at 2000 rpm across loads of 4.3-7.2 bar indicated mean effective pressure (IMEP). Cylinder pressure was collected using Kistler piezoelectric transducers in the precombustion (PC) and main combustion (MC) chambers. Ignition delays ranged from 0.74 - 1.02 ms for both operated fuels. Even though n-butanol has a lower cetane number, the high swirl in the separate combustion chamber would help advance its premixed combustion. The heat release rate of Bu25 became initially 3 J/crank-angle-degree (CAD) higher than that of ULSD#2 as load increased to 7.2 bar IMEP.

This study evaluates the performance of an indirect injection (IDI) diesel engine fueled with cotton seed biodiesel while assessing the engine's multi-fuel capability. Millions of tons of cotton seeds are available in the south of the US every year and approximately 10% of oil contained in the seeds can be extracted and transesterified. An investigation of combustion, emissions, and efficiency was performed using mass ratios of 20-50% cotton seed biodiesel (CS20 and CS50) in ultra-low sulfur diesel #2 (ULSD#2). Each investigation was run at 2400 rpm with loads of 4.2 - 6.3 IMEP and compared to the reference fuel ULDS#2. The ignition delay ranged in a narrow interval of 0.8-0.97ms across the blends and the heat release rate showed comparable values and trends for all fuel blends. The maximum volume averaged cylinder temperature increased by approximately 100K with each increase in 1 bar IMEP load but the maximum remained constants across the blends.

This study investigates the use of a natural gas derived fuel, synthetic Fischer-Tropsch (F-T) paraffinic kerosene, in both it’s neat form and blended with ultra-low sulfur diesel (ULSD#2), in a naturally aspirated indirect injected engine. A blend of a mass ratio with 20% of the F-T fuel and 80% ULSD#2 was studied for its combustion characteristics, emissions, and efficiency compared to conventional ULSD#2 at a constant speed of 2400 RPM and operating at IMEP range from 4.5 to 6.5 bar. The F-T blend produced ignition delays 17% shorter than ULSD#2 resulting in slightly lower peak apparent heat release rates (AHRR) along with decreased peak combustion temperatures, by up to 50°C. Nitrogen Oxide (NOx) emissions of the F-T blend decreased by 4.0% at 4.5 bar IMEP and at negligible amounts at 6.5 bar IMEP. The F-T blend decreased soot significantly at 5.4 bar IMEP by 40%. Efficiencies of the F-T blend were similar to ULSD#2.

This study investigates the combustion, emissions, and performance of biodiesel produced from poultry fat FAME (fatty acid methyl esters) in an indirect injection (IDI) engine. The poultry fat FAME blends were evaluated against ultra-low sulfur diesel #2 (ULSD#2) at 2600 rpm at 100% engine load. The tested biodiesel blends of poultry fat FAME included B20 to B50 measured by weight percentage in ULSD#2. Before engine testing, the energy content, dynamic viscosity, and thermal properties were measured for all poultry fat blends, 100% poultry fat FAME, and ULSD#2. Once the preliminary data had been obtained, it was determined that a blend of up to 50% poultry fat FAME would be within ASTM6751 requirements. The ignition delay stayed constant at 13 CAD for all blends tested and the gross heat release for ULSD#2 and B50 were 24.4 and 25.0 J/deg respectively.

In this study, a direct injection (DI) compression ignition engine fueled with biodiesel was supplemented with n-butanol port fuel injection (PFI) in order to simultaneously reduce in cylinder nitrogen oxides formation, decrease soot and favorable modify their trade-off. The combustion and emission characteristics were investigated for regimes of 1-5 bars IMEP at 1400 rpm. By applying this methodology, for the regimes in which the n-butanol PFI was applied, the premixed charge combustion has been split into two regions of high temperature heat release, an early one, BTDC, and a second stage ATDC, oxidizing the soot formed from biodiesel combustion and therefore modifying favorable the soot-NOx trade-off. With n-butanol injection, the soot emissions showed a significant decrease as much as 90%, concomitantly with a 50% NOx reduction at higher PFI rates. Non-regulated emissions measurements showed increases in acetaldehyde with n-butanol PFI.

This study presents the combustion and emissions characteristics of Reactivity Controlled Combustion Ignition (RCCI) produced by early port fuel injection (PFI) of low reactivity n-butanol (normal butanol) coupled with in cylinder direct injection (DI) of cottonseed biodiesel in a diesel engine. The combustion and emissions characteristics were investigated at 5.5 bars IMEP at 1400 RPM. The baseline was taken from the combustion and emissions of ULSD #2 which had an ignition delay of 13° CAD or 1.5ms. The PFI of n-butanol and DI of cottonseed biodiesel strategy showed a shorter ignition delay of 12° CAD or 1.45ms, because of the higher CN of biodiesel. The combustion proceeded first by the ignition of the pilot (cottonseed biodiesel) BTDC that produced a premixed combustion phase, followed by the ignition of n-butanol that produced a second spike in heat release at 2° CAD ATDC.

Diesel engines provide the necessary power for accomplishing heavy tasks across the industries, but are known to produce high levels of noise. Additionally, each type of fuel possesses unique combustion characteristics that lead to different sound and vibration signatures. Noise is an indication of vibration, and components under excessive vibration may wear prematurely, leading to repair costs and downtime. New fuels that are sought to reduce emissions, and promote sustainability and energy independence must be investigated for compatibility from a sound and vibrations point-of-view also. In this research, the sound and vibration levels were analyzed for an omnivorous, single cylinder, CI research engine with alternative fuels and an advanced combustion strategy, RCCI. The fuels used were ULSD#2 as baseline, natural gas derived synthetic kerosene, and a low reactivity fuel n-Butanol for the PFI in the RCCI process.

With the constant increase of fossil fuel prices and resources depletion, the researchers look beyond the usual alternative fuels for diesel engines. A lot of research is going on the employment of plastic polymers as fuels since they have a high potential to reduce diesel oil consumption and many of the aspects of their operation in diesel engines are not clarified yet. The major advantage of plastic polymers is the high calorific value, a widespread availability, and lower prices if they come from recycling. The paper presents the results from the research on a novel polyethylene blended diesel fuel and its use as alternative fuel for combustion in diesel generation plants. The authors investigated the formulation, injection, combustion and emissions of a new polyethylene-diesel fuel, obtained by an original process. The low density polyethylene (LDPE) has been mixed 5-40% by wt. with diesel by a new technology at 200 deg.