Shimadzu Solutions for Lubricant Monitoring

Importance of Lubricant Monitoring

Lubricants are critical to safe and efficient engine operation, providing friction reduction, cooling, and contaminant control. Over time, mechanical and chemical stresses degrade lubricant performance, leading to increased wear, higher maintenance costs, and potential engine failure. Routine chemical analysis of used oils enables early detection of degradation, contamination, and mechanical wear, much like blood tests reveal human health issues.

Objectives and Study Overview

This application note outlines standardized test methods for assessing lubricant condition and contaminant levels. It summarizes how Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and gas chromatography (GC) can be applied to monitor oxidation, additive depletion, soot loading, wear metals, and fuel dilution in engine oils.

Methodology

• FT-IR uses specific infrared absorption bands to quantify molecular changes such as oxidation (C–O), nitration (C–N), and water uptake (O–H), and to measure soot via strong carbon absorption between 1850–2000 cm⁻¹.
• ICP-AES analyzes metallic additives (e.g., Zn, Ca, Mo) and wear elements (e.g., Fe, Al, Cu) with low detection limits and high throughput, employing spike-recovery and dilution tests for accuracy.
• GC with flame ionization detection (FID) quantifies fuel dilution by separating and measuring unburned gasoline or diesel components in oil samples.

Used Instrumentation

• Shimadzu IRSpirit FT-IR spectrometer with Pearl Liquid Analyzer and Q-ATRS ATR prism for rapid, pretreatment-free liquid analysis.
• Shimadzu ICPE-9800 Series ICP-AES featuring a vacuum-purged optical bench and vertical torch for robust trace and major element measurement.
• Shimadzu GC-2030 gas chromatograph with ClickTek™ column connectors, large touchscreen, and optional AOC-6000 autosampler for automated sample prep and injection.

Main Results and Discussion

• FT-IR analyses revealed progressive increases in oxidation, nitration, and water incorporation in used oils, with soot levels tracked by baseline shifts in the 1850–2000 cm⁻¹ range.
• ICP-AES measurements showed consistent spike-recovery rates (~100 %) for additives and enabled detection of wear metals down to sub-µg/g levels, highlighting engine component erosion.
• GC-FID chromatograms of fuel-diluted oils exhibited clear, quantifiable peaks for diesel or gasoline fractions, supporting accurate fuel dilution assessment.

Benefits and Practical Applications

Implementing these analytical methods in routine maintenance programs allows early identification of lubricant breakdown, contamination sources, and emerging mechanical issues. This approach helps extend oil change intervals, prevent unplanned downtime, and optimize engine longevity and performance.

Future Trends and Potential Applications

Advances may include on-line spectroscopic sensors for real-time lubricant condition monitoring, integration of artificial intelligence for predictive maintenance, and miniaturized portable analyzers for field diagnostics in remote locations.

Conclusion

A multi-technique approach combining FT-IR, ICP-AES, and GC provides a comprehensive toolkit for lubricant monitoring. By tracking molecular degradation, elemental additives and wear metals, soot, and fuel dilution, operators can make informed maintenance decisions, reduce costs, and protect critical machinery.