Using Terahertz Time-Domain Spectroscopy to Discriminate among Water Contamination Levels in Diesel Engine Oil

doi:10.13031/trans.59.11448

Cited by 24 publications

(6 citation statements)

References 57 publications

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“…The highest standard deviation of measurements for the samples at 1.0 THz was 0.0001. The 1.0 THz refractive index of the 0 h sample was within 0.0001 of the refractive index of fresh diesel engine oil from a prior study using a similar THz-TDS configuration [28]. The refractive indices of oxidized diesel engine oil were higher than oxidized gasoline engine oil refractive indices of 1.4666-1.4672 at 1.0 THz for thermal oxidation times of 0-144 h [29].…”

Section: Refractive Index For Single Cuvettesupporting

confidence: 59%

“…Increased oxidation time resulted in an increase in the refractive index for diesel engine oil, similar to water contamination [28]. The increased refractive index with oxidation time was similar to oxidized gasoline engine oil [29] and increased viscosity of gasoline engine oil [25].…”

Section: Refractive Indexmentioning

confidence: 74%

“…Gasoline engine oil (SAE 5W20) was contaminated with 0%, 4%, 8%, and 12% gasoline fuel and characterized by THz-TDS, resulting in both the refractive index and absorption coefficient being used to distinguish among the contamination levels [27]. Both the refractive index and absorption coefficient of THz-TDS distinguished among 0%, 0.1% and 0.2% water contamination of diesel engine oil with the refractive index and absorption coefficient increasing with water contamination [28]. When gasoline engine oil (SAE 5W20) was thermally oxidized for 0 h, 48 h, 96 h, and 144 h and submitted to THz-TDS, the absorption coefficient was able to distinguish among the four oxidation times when the same cuvette was used [29].…”

Section: Of 10mentioning

confidence: 99%

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Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

et al. 2019

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Diesel engine oil was subjected to thermal oxidization (TO) for six periods of time (0 h, 24 h, 48 h, 72 h, 96 h, and 120 h) and was subsequently characterized by terahertz time domain spectroscopy (THz-TDS). The THz refractive index generally increased with oxidation time. The measurement method illustrated the potential of THz-TDS when a fixed setup with a single cuvette is used. A future miniaturized setup installed in an engine would be an example of a fixed setup. For the refractive index, there were highly significant differences among the oxidation times across most of the 0.3–1.7 THz range.

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Section: Refractive Index For Single Cuvettesupporting

confidence: 59%

Section: Refractive Indexmentioning

confidence: 74%

Section: Of 10mentioning

confidence: 99%

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Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

et al. 2019

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“…In this context, an improved knowledge of the optical and dielectric properties of these fuels and their mixtures is interesting because they are related to the nonlinearities in some properties of relevance for internal combustion engines [13,14]. An additional possibility is their use as onboard indicators of the fuel quality [15] and the presence of impurities [16,17] and as quality control indicators on production and blending processes [18].…”

Section: Introductionmentioning

confidence: 99%

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

Patiño-Camino

Cova-Bonillo

Rodríguez–Fernández

et al. 2021

J Infrared Milli Terahz Waves

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Binary blends of ethanol-diesel, n-butanol-diesel, ethanol-biodiesel, and n-butanol-biodiesel have been analyzed with terahertz time-domain spectroscopy in a full range of concentrations and at room temperature. The real and imaginary parts of the complex dielectric constant of the blends were obtained from the spectra and fitted to the Debye model at low volume concentrations (up to 7.5% for ethanol in diesel and up to 20% for butanol in diesel, ethanol in biodiesel, and butanol in biodiesel blends), considering the number of relaxation processes recommended in the literature for each pure component (single for diesel, double for biodiesel, and triple for alcohols). The results indicate that the faster relaxation time in low alcohol mixtures is longer than in pure alcohols. This relaxation time increases as the alcohol content increases. The excess of the real and of imaginary parts of the dielectric constant were individually determined. The analysis of such excess and of its different contributions (volume, contrast, and interactions) suggests that the intermolecular interactions between the different components of the blends dominate the relaxation dynamics in each pseudo-binary system. Ethanol was found to move blends further away from ideal behavior than n-butanol. In fact, these latter blends showed the most ideal behavior, suggesting that the length of the alcohol carbon chain plays an important role. This information allows a possible link between the nonlinear behavior of the physicochemical properties of the blends (e.g., viscosity and surface tension) and the molecular interactions between their constituent molecules. This relation could have direct application for monitoring the fuel composition and quality in the vehicle control systems.

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“…These include viscosity sensors [19], mass sensors [21], cyclic voltammetry [23], carbon nanotube sensors [25], and photoacoustic detection [28]. Other methods have included Fourier-transform infrared (FT-IR) spectroscopy [1,[30][31][32][33][34][35], to determine oxidation [30,31,36] and water contamination [33,34,37], and terahertz timedomain spectroscopy [38,39].…”

Section: Introductionmentioning

confidence: 99%

UV-Visible Spectrophotometer for Distinguishing Oxidation Time of Engine Oil

et al. 2021

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Samples of gasoline engine oil (SAE 5W20) that had been exposed to various oxidation times were inspected with a UV-Visible (UV-Vis) spectrophotometer to select the best wavelengths and wavelength ranges for distinguishing oxidation times. Engine oil samples were subjected to different thermal oxidation periods of 0, 24, 48, 72, 96, 120, and 144 hours, resulting in a range of total base number (TBN) levels. Each wavelength (190.5–849.5 nm) and selected wavelength ranges were evaluated to determine the wavelength or wavelength ranges that could best distinguish among all oxidation times. The best wavelengths and wavelength ranges were analyzed with linear regression to determine the best wavelength or range to predict oxidation time.

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Using Terahertz Time-Domain Spectroscopy to Discriminate among Water Contamination Levels in Diesel Engine Oil

Cited by 24 publications

References 57 publications

Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

UV-Visible Spectrophotometer for Distinguishing Oxidation Time of Engine Oil

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