Findings from a fleet test on the performance of two engine oil formulations in automotive CNG engines

Abstract

This work presents a comparative assessment of engine oil performance on field test using urban transport vehicles powered by CNG engines using two different mineral oil formulations approved by engine manufacturer. The first one is considered as a baseline reference, and the second one is a higher quality formulation in terms of base-stock refining and additive content. Higher quality oil has shown a significant enhanced lubricant performance, leading to reach the oil drain interval defined by engine manufacturer on these engines without penalties in maintenance costs.In order to assess oil performance, an oil analysis program has been established for oil samples collected from vehicles operated under real service conditions in an urban transport fleet. Monitored parameters include: oxidation, nitration, aminic antioxidant additives depletion, anti-wear additives depletion, TAN, TBN and RUL number (as an estimation of antioxidant additive depletion including aminic and ZDDP).Results obtained in more than 90 samples from 15 different vehicles have shown higher degradation rates for low quality lubricant oil formulation. This deviation can be explained taking into account factors related with lower antioxidant additives content and lower thermal stability that can be mainly related with the base stock quality. This lower oil performance can be finally converted into higher vehicle maintenance cost and lower engine reliability

Assessment of low-viscosity oil performance and degradation in a heavy duty engine real-world fleet test

“…[27][28][29] On the other hand, FT-IR has been assessed recently as an analytical technique to detect presence of certain types of additives (due to the presence of characteristic molecular bonds), and some methodologies have been developed to quantify them. 30 In this study, it has been used to quantify the aminic and antiwear additive depletion, using FT-IR spectra methodology measurement procedures based on ASTM D6810 31 and ASTM D6971. 32 In Table 1, a basic description of the FT-IR quantification measurement procedures is presented.…”

Oxidative Stability of the Plain and Additized Mineral Base Oil Samples Monitored through Gas Chromatography–Mass Spectrometry

“…Many analytical methods have been reported in the literature for monitoring oil degradation in the absence and presence of antioxidants. These include Fourier transform infrared spectroscopy (FTIR), pressure differential scanning calorimetry (PDSC), gel permeation chromatography (GPC), flow injection analysis (FIA)–visible spectrometry, X-ray absorption near-edge structure (XANES), nuclear magnetic resonance (NMR), and gas chromatography–mass spectrometry (GC–MS) . Among these methods, GC–MS has been reported to be an effective method for analysis of residual products, including organic acids, which are commonly formed in lube oils via chemical oxidation .…”