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The Coal-To-Liquid (CTL) synthetic aviation fuel, Iso-Paraffinic Kerosene (IPK), was studied for ignition delay, combustion delay, pressure trace, pressure rise rate, apparent heat release rate in an experimental single cylinder indirect injection (IDI) compression ignition engine and a constant volume combustion chamber (CVCC). Autoignition characteristics for neat IPK, neat Ultra-Low Sulfur Diesel (ULSD), and a blend of 50%IPK and 50% ULSD were determined in the CVCC and the effects of the autoignition quality of each fuel were determined also in an IDI engine. ULSD was found to have a Derived Cetane Number (DCN) of 47 for the batch used in this experimentation. IPK was found to have a DCN of 25.9 indicating that is has a lower affinity for autoignition, and the blend fell between the two at 37.5. Additionally, it was found that the ignition delay for IPK in the CVCC was 5.3 ms and ULSD was 3.56 ms.

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).

"The Single Fuel Forward Policy" legislation enacted in the United States mandates that deployed U.S. military ground vehicles must be operable with aviation fuel (JP-8). This substitution of JP-8 for diesel raises concerns about the compatibility of this fuel with existing reciprocating piston engine systems. This study investigates the combustion, emissions, and performance characteristics of blends of JP-8 and Ultra Low Sulfur Diesel (ULSD) fuels with similar cetane numbers (CN), 48 (JP-8) and 47(ULSD), respectively, in a direct injection (DI) compression ignition engine over the load range of 3-8 bar imep at 1400 rpm. The results showed that JP-8 blends and ULSD had ignition delays ranging from approximately 1.0-1.4 ms and an average combustion duration time in the range of 47-65 CAD. Cylinder maximum heat flux values were found to be between 2.0 and 4.4 MW/m₂, with radiation flux increasing much faster than convection flux while increasing the imep.

This study investigates combustion and emissions of Jet-A in an indirect injection (IDI) compression ignition engine and a direct injection (DI) compression ignition engine at 4.5 bar IMEP and 2000 RPM. The Jet-A was blended with ULSD that resulted in 75%Jet-A and 25% ULSD#2 by mass. Both engines were instrumented with Kistler pressure sensors in the main chamber and the IDI engine had a second pressure sensor in the pre-chamber. Combustion properties and emissions from both engines using the 75% jet-A blend (75Jet-A) were compared to a baseline test of Ultra Low Sulfur Diesel #2 (ULSD). The ignition delay was shorter when running on 75Jet-A compared to ULSD in the DI engine. For ULSD, the ignition delay was 1.8 ms and it reduced to 1.7 ms when operating on 75Jet-A (difference of 6%). In the IDI engine the ignition delay for both fuels was 2.3 ms based off the gross heat release in the Pre-Chamber.

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.

An investigation into emissions differences and their correlations with differing combustion characteristics between F24 and Jet-A was conducted. Raw emissions data was taken from a single stage jet engine by a FTIR gas analyzer. Measurements of H2O, CO2, CO, NOx, and total hydrocarbon emissions (THC) were taken at 60K, 65K, and 70K RPM. At 70K RPM Jet-A and F-24 the emissions were similar at approx.: 4% H2O, 3% CO2, 970 PPM CO, 28 PPM NOx. Jet-A THC emissions were approx.: 1200 PPM THC, F24 THC emissions were lower by over 60%. The significantly lower amount of THC emissions for F24 suggests more complete combustion compared to Jet-A.

In this study, the combustion and emissions characteristics of n-butanol/GTL and n-butanol/ultra-low sulfur diesel (ULSD) blends are compared in a single-cylinder experimental diesel engine. The n-butanol was blended with a Fischer-Tropsch (FT) gas-to-liquid (GTL) fuel, at 25% and 50% mass. N-butanol was also blended with ULSD at the same mass ratios. FT fuels are an attractive alternative to petroleum based fuels because they can be used as a drop-in fuel with existing infrastructure. N-butanol is renewable fuel capable of being produced from waste biomass sources. The investigations were conducted at 1500 rpm and three loads of 2.75, 4.75, and 6.75 IMEP, representative for the research engine. 15% exhaust gas recirculation was utilized along with a supercharger to increase the intake pressure to 1.2 bar absolute. Neat ULSD and GTL, respectively, were investigated as a baseline.

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.

In this study, a Premixed Charge Compression Ignition (PCCI) obtained by sequential dual fueling strategy of n-butanol port fuel injection (PFI) and direct injection of ULSD#2 was investigated against binary mixtures combustion (defined as premixed in the tank) of n-butanol and ultra-low sulfur diesel (ULSD#2) with the same n-butanol to diesel ratios (35%, 50%, 65% by mass) in an omnivorous compression ignition engine. The hypothesis of the study is that combustion phasing (respectively CA50) can be successfully controlled by the above named strategies. Both fueling strategies controlled the high reactivity of the ULSD#2 and slowed down the chemical reactions with the low cetane number fuel, n-butanol. These processes led to fuel reactivity stratification and an increase in the ignition delay observed as the amount of n-butanol increased.

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.

Recent legislation entitled “The Single Fuel Forward Policy” mandates that all vehicles deployed by the US military be operable with aviation fuel (JP-8). Therefore, the authors are conducting an investigation into the influence of JP-8 on a diesel engine's performance. The injection, combustion, and performance of JP-8, 20-50% by weight in ULSD (diesel no.2) mixtures (J20-J50) produced at room temperature, were investigated in a small indirect injection, high compression ratio (24.5), 77mm separate combustion chamber diesel engine. The effectiveness of JP8 for application in an auxiliary power unit (APU) at continuous operation (100% load) of 4.78bar bmep/2400rpm was investigated. The blends had an ignition delay of approximately 1.02ms that increased slightly in relation to the amount of JP-8 introduced. J50 and diesel no.2 exhibited similar characteristics of heat release, the premixed phase being combined with the diffusion combustion.

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.

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.

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.