Comparative Evaluation of Ethanol, n-Butanol, and Diethyl Ether Effects as Biofuel Supplements on Combustion Characteristics, Cyclic Variations, and Emissions Balance in Light-Duty Diesel Engine

Rakopoulos, Dimitrios C.; Rakopoulos, C.D.; Giakoumis, Evangelos G.; Komninos, N.P.; Kosmadakis, George; Papagiannakis, Roussos G.

doi:10.1061/(asce)ey.1943-7897.0000399

Cited by 78 publications

(19 citation statements)

References 48 publications

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“…In addition, too low cetane number will increase emissions of CO, HC, and NO x . The main reason is that the lower cetane number leads to unstable diesel engine operation owing to cyclic cylinder pressure variability or irregularity . Therefore, the surfactant additive not only can effectively dissolve mixtures of ethanol and diesel, but also should have a high cetane number to ensure the ignition of ethanol/diesel fuel.…”

Section: Introductionmentioning

confidence: 99%

Effects of polyoxymethylene dimethyl ethers on the solubility of ethanol/diesel and hydrous ethanol/diesel fuel blends

Jin

Zhang

Wang

et al. 2019

Energy Science & Engineering

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Ethanol is an oxygen‐containing renewable clean fuel. The use of ethanol in engines can reduce greenhouse emissions and pollutant emissions of NOx and soot. However, ethanol has limited solubility in diesel fuel. Polyoxymethylene dimethyl ethers (PODE) can improve the miscibility and cetane number of ethanol‐diesel blend. To evaluate the solubilizing ability of PODE on the mixture of ethanol and diesel, the phase behavior of the ternary system (PODE, anhydrous ethanol, and diesel) was investigated at different ambient temperatures. Additionally, the blend can easily absorb water from ambient humidity because of the additional ethanol, which may cause phase separation. Thus, the effect of water addition on the phase behavior of the system was studied. In the current study, the blend of ethanol (100%, 98%, 95% purity) and diesel fuel was used as a solute with different diesel blending ratios. Then, PODE was gradually added into blend until phase boundaries of ternary system appeared. Results show that the ability of PODE in the blend is greatly affected by ambient temperature, particularly above 10°C. The addition of water greatly destroys the phase stability of the ternary system and increases demand for PODE due to the hydrophobicity of diesel.

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Section: Introductionmentioning

confidence: 99%

Effects of polyoxymethylene dimethyl ethers on the solubility of ethanol/diesel and hydrous ethanol/diesel fuel blends

Jin

Zhang

Wang

et al. 2019

Energy Science & Engineering

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“…Cyclic variations affect the engine performance and emissions, especially in spark-ignition (SI) engines, possibly leading to engine instability regimes in the most extreme cases [1]. In diesel engines this phenomenon is less intensive [2,3], but with similar outputs [4,5]. Its main causes in SI engines are mostly related to the gas properties at the vicinity of the spark plug, such as the mixture velocity and inhomogeneity, the local turbulence level and intensity, as well as the spark plug specifications.…”

Section: Introductionmentioning

confidence: 99%

A Fast CFD-Based Methodology for Determining the Cyclic Variability and Its Effects on Performance and Emissions of Spark-Ignition Engines

Kosmadakis

Rakopoulos

2019

Energies

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A methodology for determining the cyclic variability in spark-ignition (SI) engines has been developed recently, with the use of an in-house computational fluid dynamics (CFD) code. The simulation of a large number of engine cycles is required for the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) to converge, usually more than 50 cycles. This is valid for any CFD methodology applied for this kind of simulation activity. In order to reduce the total computational time, but without reducing the accuracy of the calculations, the methodology is expanded here by simulating just five representative cycles and calculating their main parameters of concern, such as the IMEP, peak pressure, and NO and CO emissions. A regression analysis then follows for producing fitted correlations for each parameter as a function of the key variable that affects cyclic variability as has been identified by the authors so far, namely, the relative location of the local turbulent eddy with the spark plug. The application of these fitted correlations for a large number of engine cycles then leads to a fast estimation of the key parameters. This methodology is applied here for a methane-fueled SI engine, while future activities will examine cyclic variations in SI engines when fueled with different fuels and their mixtures, such as methane/hydrogen blends, and their associated pollutant emissions.

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“…The theoretical and practical issues associated with the development, production, and the test results of turbocharged auto-tractor Diesel engines and their fuel systems with the high-pressure, electro-hydraulically controlled injectors to efficiently operate on alternative fuels such as dimethyl ester (DME) and a natural gas presents Reference [19]. The extended, comprehensive engine tests with straight vegetable oils [20][21][22] and rapeseed oil blends with diesel fuel [23,24], rapeseed biodiesel [25], and biodiesel blends with diesel fuel [26,27], ethanol-diesel [28,29], ethanol-diesel-biodiesel [30], n-butanol-diesel fuel blends [31][32][33], and binary blends of SVO or biodiesel with n-butanol or DEE [22] have been performed pursuing a wider use of renewable biofuels.…”

Section: Introductionmentioning

confidence: 99%

Study of the Effects of Biofuel-Oxygen of Various Origins on a CRDI Diesel Engine Combustion and Emissions

2019

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The paper presents the effects made by a fossil diesel–HRD (Hydrotreated Renewable Diesel) fuel blend containing Ethanol (E) or Biodiesel (B) on the combustion process, Indicated Thermal Efficiency (ITE), smoke, and pollutant emissions when running a turbocharged Common Rail Direct Injection (CRDI) engine under medium (50% of full load), intermediate (80% of full load), and full (100%) loads at maximum torque speed of 2000 rpm. These loads correspond to the respective Indicated Mean Effective Pressures (IMEP) of 0.75, 1.20, and 1.50 MPa, developed for the most common operation of a Diesel engine. The fuel-oxygen mass content was identically increased within the same range of 0 (E0/B0), 0.91 (E1/B1), 1.81 (E2/B2), 2.71 (E3/B3), 3.61 (E4/B4), and 4.52 wt% (E5/B5) in both E and B fuel groups. Nevertheless, these fuels still possessed the same blended cetane number value of 55.5 to extract as many scientific facts as possible about the widely differing effects caused by ethanol or biodiesel properties on the operational parameters of an engine. Both quantitative and qualitative analyses of the effects made by the combustion of the newly designed fuels with the same fuel-oxygen mass contents of various origins on the engine operational parameters were conducted comparing data between themselves and with the respective values measured with the reference (‘baseline’), oxygen-free fuel blend E0/B0 and a straight diesel to reveal the existing developing trends. The study results showed the positive influence of fuel-oxygen on the combustion process, but the fuel oxygen enrichment rate should be neither too high nor too low, but just enough to achieve complete diffusion burning and low emissions. The Maximum Heat Release Rate (HRRmax) was 3.2% (E4) or 3.6% (B3) higher and the peak in-cylinder pressure was 4.3% (E3) or 1.1% (B5) higher than the respective values the combustion of the reference fuel E0/B0 develops under full load operation. Due to the fuel-oxygen, the combustion process ended by 7.3° (E4) or 1.5° crank angle degrees (CADs) (B4) earlier in an engine cycle, the COV of IMEP decreased to as low as 1.25%, the engine efficiency (ITE) increased by 3.1% (E4) or decreased by 2.7% (B3), while NOx emissions were 21.1% (E3) or 7.3% (B4) higher for both oxygenated fuels. Smoke and CO emissions took advantage of fuel-oxygen to be 2.9 times (E4) or 32.0% (B4) lower and 4.0 (E3) or 1.8 times (B5) lower, respectively, while THC emissions were 1.5 times (E4) lower or, on the contrary, 7.7% (B4) higher than the respective values the combustion of the fuel E0/B0 produces under full load operation. It was found that the fuel composition related properties greatly affect the end of combustion, exhaust smoke, and pollutant emissions when the other key factors such as the blended cetane number and the fuel-oxygen enrichment rates are the same in both fuel groups for any engine load developed at a constant (2000 rpm) speed.

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Comparative Evaluation of Ethanol, n-Butanol, and Diethyl Ether Effects as Biofuel Supplements on Combustion Characteristics, Cyclic Variations, and Emissions Balance in Light-Duty Diesel Engine

Cited by 78 publications

References 48 publications

Effects of polyoxymethylene dimethyl ethers on the solubility of ethanol/diesel and hydrous ethanol/diesel fuel blends

Effects of polyoxymethylene dimethyl ethers on the solubility of ethanol/diesel and hydrous ethanol/diesel fuel blends

A Fast CFD-Based Methodology for Determining the Cyclic Variability and Its Effects on Performance and Emissions of Spark-Ignition Engines

Study of the Effects of Biofuel-Oxygen of Various Origins on a CRDI Diesel Engine Combustion and Emissions

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