In making this assessment, OELCHECK diagnostic engineers benefit from their extensive experience and our comprehensive database. Click here for details. That doesn’t bode well for motorists driving modern turbocharged vehicles that create increased heat compared to older vehicles. Bench oxidation tests have a difficult time replicating field oxidation mechanisms. This means the lubricant can be heated above its recommended stable temperature. In addition, rust and corrosion can also form on the equipment.
Or metal. A clear peak is visible in the IR spectrum of an oxidised mineral oil at a wave number of about 1,710 cm-1. The introduction has been well intended with the key benefits of reduced test costs and less time required for lubricant performance evaluation. Oxidation occurs more rapidly in high temperatures and in the presence of water, acids, or catalysts such as copper. Currently, the main drivers for engine oil developments are improving fuel economy, engine wear protection, cost reduction and more specific issues including low speed pre-ignition. Since oxidation is one of the key oil degradation mechanisms, Infineum wanted to better understand if currently used bench oxidation tests produce realistic data. In PHEVs specifically, no. Making it harder to develop lubricants that can meet the needs of future hardware. Motor oil isn’t immune to oxidation.
As you might expect, oxygen causes engine oil oxidation. In some cases, additive depletion and a breakdown in the base oil can also occur.
For example, antioxidant additives help slow the rate of oxidation. Aug 15, 2019 | Agriculture, Automotive, Construction, Engine Oil, Fleet.
And, because AMSOIL synthetic lubricants don’t contain contaminants like conventional oils, their base composition doesn’t accelerate oxidation. This is down to the mechanism of viscosity increase, which in the bench test is disproportionally affected by the high temperatures and Fe(AcAc)3 present compared with the chassis dynamometer. Suddenly, the 5W-30 motor oil your engine was designed to use is now essentially a 5W-20 oil, and wear protection may be compromised. Based on the Arhenius Rule, for every 10°C increase in temperature above 40°C, the oil life is halved. The process of oxidation is naturally occurring in the oil, but the rate at which this happens depends on the following factors: Temperature – the higher the temperature, the shorter the oil life. Until then, we at OELCHECK wish to assure our customers that when assessing the ageing of modern engine oils we do not rely solely on oxidation as determined in accordance with DIN 51453, which is not usable in this situation.
Motor oil can deteriorate by becoming contaminated, the additives depleting over time or both. The mechanisms of real engine oil oxidation are fundamentally different to those of bench oxidation tests. These results lead us to the conclusion that the CEC L-109 bench test, and the many other similar bench tests, although well intended, have limitations. NITRATION — Nitration is of concern in engine oils, particularly natural gas engine oils. Though all motor oils eventually deteriorate, synthetic oils last longer than conventional oils and deliver improved protection against wear and deposits. Fuel dilution – Fuel can wash past the piston rings and contaminate the motor oil, causing it to lose viscosity. Oxygen comprises about 20 percent of our atmosphere. During the wear process in a real engine for example, tiny wear iron particles are created. Through industry testing conducted as part of the transition to API CK-4, United Super Premium Fleet SAE 15W-40 exhibited a 45% improvement in oxidative stability over the specification limit and better protection against increased viscosity as set forth in the Volvo T-13 test.
Perhaps the time has come for industry to apply a high level of scrutiny and to conduct a cost/benefit analysis of bench and analytical tests to ensure they can model real field phenomena and are relevant to modern engines. Everyone knows that oxygen will quickly cause a cut apple to turn brown. The value at 1,710 cm-1 often lies on a shoulder of the peak, giving rise to what appears to be strongly varying oxidation values. In fact, AMSOIL Signature Series Synthetic Motor Oil performs so well you can go up to 25,000 miles/one year between oil changes (15,000 miles/one year in severe service) if you want, saving money. Every 18ºF (10ºC) increase in temperature doubles the rate of oxidation. In his 2016 UNITI presentation, Dave built upon the presentation he delivered in 2015, in which he examined the effect of oil degradation on lubricant performance [Read the Insight article here]. Long periods of oil use, relatively high operating temperatures or rising contamination levels aggravate oil oxidation and the associated formation of acidic reaction products.
Even the best oils eventually require you to change them. Infineum International Limited, Facebook We use cookies to distinguish you from other users, to improve your user experience and to understand how you use our site. The majority of additive packages are designed to perform specific functions and are used up during the life of the oil.
Oxidation results can be followed by measuring the increase in the acid number of the fluid (or the loss in base number in engine oils caused by the formation of acids), viscosity (caused by the formation of condensation products), FTIR carbonyl oxidation (the ketones, aldehydes, esters and acids formed form the oxidation reactions) and insoluble products. Ask about our Used Oil Analysis Program.
AMSOIL synthetic lubricants are formulated using base oils with a saturated molecular structure, meaning oxygen is prevented from attaching. Looking at the viscosity increase response, a much bigger difference can be observed, with the CEC L-109 test generating a large viscosity increase when compared with the chassis dynamometer. However, as Infineum's Dave Coultas explained at this year’s UNITI conference, the bench oxidation tests currently in use are unable to mimic the mechanisms of real engines and may restrict future formulation developments. In assessing how much longer a gas engine oil can be used or whether an oil change is necessary, oil ageing or oil oxidation is a crucial factor. This innovation increases the interaction between oil molecules, creating a greater resistant molecular structure. While these drivers push oil formulations in one direction, unfortunately bench tests, like the CEC L-109, are driving the formulation space in exactly the opposite direction and can hinder innovation. Oxidation – The interaction between oxygen molecules and motor oil molecules naturally leads to chemical breakdown.