Absorption Wavebands for Discriminating Oxidation Time of Engine Oil as Detected by FT-IR Spectroscopy

Varnish Formation and Removal in Lubrication Systems: A Review

This study presents the current literature regarding the investigation of varnish contamination among the various types of lubricant contaminations. As the duration of use of lubricants increases, the lubricant deteriorates and may become contaminated. Varnish has been known to cause filter plugging, sticking of the hydraulic valves and fuel injection pumps, flow obstruction, clearance reduction, poor heating and cooling performance, and increased friction and wear in various lubrication systems. These problems may also result in mechanical system failures, performance degradation, and increased maintenance and repair costs. To improve the problems caused by varnish contamination, an adequate understanding of varnish is required. Therefore, in this review, the definitions and characteristics, generating machinery, generating mechanisms, causes, measurement methods, and prevention or removal methods of varnish are summarized. Most of the data presented herein are reports from manufacturers related to lubricants and machine maintenance that are included in published works. We expect that this summary will be helpful to those who are engaged in reducing or preventing varnish-related problems.

UV-Visible Spectrophotometer for Distinguishing Oxidation Time of Engine Oil

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.

FTIR Spectrometry with PLS Regression for Rapid TBN Determination of Worn Mineral Engine Oils

The TBN (Total Base Number) parameter is generally recognized by both engine oil processors and engine manufacturers as a key factor of oil quality. This is especially true for lubricating oils used in diesel and gas engines, which are exposed to relatively high temperatures and, therefore, require more effective protection against degradation. The FTIR spectrometry method together with a multivariate statistical software helped to create a model for the determination of TBN of worn motor oil SAE 15W-40 ACEA: E5/E7, API: CI-4. The best results were provided using a model FTIR with Partial Least Squares (PLS) regression in an overall range of 4000–650 cm−1 without the use of mathematical adjustments of the scanned spectra by derivation. Individual spectral information was condensed into nine principal components with linear combinations of the original absorbances at given wavenumbers that are mutually not correlated. A correlation coefficient (R) between values of TBN predicted by the FTIR-PLS model and values determined using a potentiometric titration in line with the ČSN ISO 3771 standard reached a value of 0.93. The Root Mean Square Error of Calibration (RMSEC) was determined to be 0.171 mg KOH.g−1, and the Root Mean Square Error of Prediction (RMSEP) was determined to be 0.140 mg KOH.g−1. The main advantage of the proposed FTIR-PLS model can be seen in a rapid determination and elimination of the necessity to work with dangerous chemicals. FTIR-PLS is used mainly in areas of oil analysis where the speed of analysis is often more important than high accuracy.

Determination of Tractor Engine Oil Change Interval Based on Material Properties

This article focuses on the issue of motor oils used in the engines of non-road mobile machinery (NRMM), more specifically tractors. The primary goal of the paper is to determine the appropriate replacement interval for these oils. The physical properties of the examined samples were first determined by conventional instruments. Furthermore, the concentrations of abrasive metals, contaminants, and additive elements were measured using an optical emission spectrometer. Lastly, the content of water, fuel, and glycol and the products of oxidation, nitration, and sulfation were determined by using infrared spectrometry. The measured values were compared to the limit values. Based on the processing and evaluation of these analyses, the overall condition of the oils was assessed and subsequently the optimal exchange interval of the examined oils was determined. In addition, a risk analysis of the outage was performed. Due to the high yields of crops, farmers can lose a significant amount of product when a tractor is not functioning during the harvest period. This loss is calculated in the paper.

Evaluating petrol engine oil deterioration through oxidation and nitration parameters by low-cost IR sensor

For the proper working of the internal combustion engine, engine oil plays a significant role. The performance of the engine is greatly affected by oil that has degenerated. In order to determine the optimal gap between oil changes, it is crucial to measure the deterioration in the engine oil. Multiple parameters like oxidation, nitration, viscosity and so on are brought into use. One of the methods used to quantify the deterioration in the engine oil is the Fourier Transform Infrared (FTIR) spectroscopy. The main parameters of the engine oil are distinguished by this method by utilizing Infrared (IR) absorption at different bandwidths. The two significant parameters in engine oil deterioration are oxidation and nitration. However, the limitation of the FTIR method is that it is more expensive and since it uses huge machinery, it requires a lot of area. Hence, the use of this method is not possible in the field area due to the need for space. It is this major limitation that is the motivation for proposing an inexpensive, yet handy system, using an IR sensor set up, in this paper. This system is used for measuring the transmittance of engine oil that has degenerated. For this paper, we collected random samples at various times from service stations that were specifically authorized. These samples were used in experiments based on the FTIR spectroscopy and UV spectrophotometer and the results were compared using the IR sensor setup. Investigation of the experimental results showed that monitoring oil transmittance using an IR sensor setup is possible, and a robust relationship between oxidation and nitration and the transmittance of the oil was observed. Moreover, a pattern of deterioration for a specific engine oil (SAE 5W30) which is utilized for passenger cars and light duty vehicles was also established.