High sensitivity wide range ethanol concentration measurements in ethanol blended petrol using weakly tilted fiber Bragg grating

Abstract Due to worldwide increasing interest towards usage of bio-ethanol blended fuel, high accuracy measurement of ethanol content in ethanol blended petrol (EBP) is of high importance for fuel quality assurance. In the present work, we report high sensitivity detection of ethanol concentration in ethanol-petrol solution in wide concentration range using a tilted fiber Bragg grating (TFBG) sensor. This sensor relies on the spectral shift measurement of cut-off mode with the change in ethanol concentration. In addition, the TFBG core mode insensitivity towards surrounding medium refractive index was utilized for simultaneous and independent measurement of ethanol concentration and sample temperature. The ethanol blended petrol concentration measurements are done in the range of 0–100% v/v. The TFBG sensor shows excellent linearity with regression coefficient R 2 = 0.99949 throughout the investigated concentration range. The observed sensitivity of the TFBG sensor is 251.52 ± 1.8 pm/% v/v of ethanol and the resolution is ~ 0.1% v/v ethanol in EBP. To the best of our knowledge, these reported values are much better than earlier reported values in literature in terms of sensitivity, dynamic range, linearity, and resolution. Also, the present sensor does not require any coating material for ethanol detection which makes it more physically/chemically rugged and easier to fabricate and implement.