Gasohol Quality Control for Real Time Applications by Means of a Multimode Interference Fiber Sensor

Abstract

In this work we demonstrate efficient quality control of a variety of gasoline and ethanol (gasohol) blends using a multimode interference (MMI) fiber sensor. The operational principle relies on the fact that the addition of ethanol to the gasohol blend reduces the refractive index (RI) of the gasoline. Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the MMI peak wavelength response. Gasohol blends with ethanol contents ranging from 0% to 50% has been clearly identified using this device, which provides a linear response with a maximum sensitivity of 0.270 nm/% EtOH. The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends.

A Simple Optical Sensor Based on Multimodal Interference Superimposed on Additive Manufacturing for Diameter Measurement

“…Multimodal Interference (MMI) devices based on optical fibers have been extensively investigated and act as sensors in recent years for different applications, such as temperature [10], strain [11][12][13], air pressure [14], vibration [15], gasohol quality [16], structure health monitoring [17], flow rate [18,19], and so on. There exist several types of MMI structures, such as the Sagnac Interferometer [20], Fabry-Perot Interferometer [21], and Singlemode-Multimode-Singlemode (SMS) [22].…”

Gasoline Quality Sensor Based on Tilted Fiber Bragg Gratings

“…Optical fiber sensors for gasoline quality monitoring usually probe the refractive index changes, which are verified when different contents of the adulterated solvents are diluted in gasoline. Long-period gratings (LPG) [5,6], singlemode-multimode-singlemode (SMS) structures [7], and thinned Bragg gratings [8] are technologies able to evaluate fuel conformity. Moreover, gasoline sensors based on Fabry-Perot interferometers prepared on fiber tips [9] and on long-period gratings associated with fiber tapers [10] have been reported in the literature.…”

“…Moreover, gasoline sensors based on Fabry-Perot interferometers prepared on fiber tips [9] and on long-period gratings associated with fiber tapers [10] have been reported in the literature. However, in these investigations, the sensing experiments are based on spectral measurements [5][6][7][8][9] or make use of sophisticated interrogation schemes (such as the setup reported in [10], based on white light interferometry). Regarding the use of spectral measurements, even though they are highly useful for sensing, their realization involves the utilization of expensive optical spectrum analyzers, which can ultimately limit their application for practical purposes.…”

Sensitivity enhancement experimental demonstration using a low cutoff wavelength SMS modified structure coated with a pH sensitive film

“…In this paper, we present a less expensive pH sensor with higher sensitivity by unit compared to the previously cited researches. Particularly, the optical fiber pH sensors can be applied in: biochemistry [14,15], structural monitoring [16] and energy [17,18,19].…”