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Savant Labs
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Addressing the Need for Electric Driveline Fluid Testing - CEC L-48 Oxidation

CEC L-48

Savant Author:  Canika Owen-Robinson, New Business Integration Leader 

Savant is happy to announce the addition of CEC L-48 Oxidation Stability of Lubricating Oils Used in Automotive Transmissions by Artificial Aging, an oxidation test to address future needs for electric driveline fluids. There is an upcoming SAE instruction document SAE J3200 Electric Drivetrain Fluids (DEF), under development in the ballot stage with a focus on thermal and electrical conductivity, oxidation, and copper corrosion which includes CEC-L-481. This lab-scale oxidation method ages oil in laboratory glassware. The method is used to evaluate key parameters that are related to longer oil service lifetime, better protection, fuel efficiency improvement and durability, reduced carbon emissions, and lower operating costs which have also led to higher operating temperatures for axle lubricants. These higher operating temperatures have placed more severe demands on the thermal and oxidative performance of axle lubricants. 

CEC L-48 assesses resistance of lubricants to high temperature oxidation and the ability to resist oil degradation and sludging. A lubricant is heated and aerated under controlled conditions. The samples are tested for kinematic viscosity, Figure 1, and infra-red spectroscopy, Figure 2. The viscosity increase and the degree of oxidation are determined by comparing the fresh and aged oil. Lubricant performance is evaluated by measuring the change in kinematic viscosity at 40°C and 100°C. The degree of oxidation is measured by FTIR in accordance with ASTM D7214 which quantifies the Peak Area Increase (PAI) in the carbonyl region. Oxidation peak height is also measured in accordance with DIN 51453. In both cases, the smaller the increase the better. In addition, sludge rating is determined by visual examination of the aged oil. Typical conditions are temperature: 150°C to 170°C and 192 hrs duration.

                                                                Viscosity Change OTH Q3

                                                                                                          Figure 1.

                                                        FTIR OTH Q3

                                                                                                             Figure 2. 

OEV enginexidation can lead to oil degradation, resulting in increases in viscosity, acid number, and/or sludge and deposit tendencies. An increase in KV can lead to increased friction and lower wear-prevention, which can reduce efficiency and increase wear. Increase in acid number will form undesirable gums and lacquers. Sludge enhances corrosion rates due to acidic compounds which can lead to malfunctioning of valves, confined space blocking, and orifice clogging. If a lubricant shows ability to resist degradation in these bench tests, it can indicate its ability to provide longer oil life and better protection.

As a reminder, our On the Horizons Q4, 2021 issue focused on Electric Vehicle Lubricant and Fluids Testing. In addition to characteristics common to all drivetrain lubricant performance, such as wide temperature range and anti-wear protection, Savant also offers the Conductive Deposit Test (CDT) which exists to determine to what extent conductive deposits will form on exposed copper in tight spaces exposed to lubricant or vapor and the Wire Corrosion Test (WCT) which identifies the rate of corrosion and depletion of copper on the test wire in both fluid and vapor states.

The advancements of electric vehicles and their specialized lubricants are creating opportunities for innovation in fluids and fluid testing. Savant Labs has been developing expertise in these new areas and is available to support our customers' testing needs.   

Contact us to learn more.