While it might seem that hybrids and EVs need less maintenance, in reality, specific lubricants are required as are specific service intervals.
As conversations about the future of the automobile continue, with a current emphasis on electrification, lubricants are and will continue to play a crucial role.
When it comes to the protection of the moving parts and maintenance, as Jörg Spanke, General Manager and Lubricant Specialist at Shell’s operations in Hamburg, Germany notes, there are some specifics to consider.
Dispelling EV and hybrid maintenance myths
Autosphere: There is still an inaccurate consensus that hybrids and EVs need little to no maintenance, but often such an approach from consumers can drastically shorten the lifespan and operation of these vehicles. Can you perhaps dispel some of these myths?
Jörg Spanke: Absolutely.
Let’s start with the hybrids. With a full hybrid, you have a regular internal combustion engine and also an electric motor that works in parallel with each other.
The electric motor supports the internal combustion engine and depending on vehicle speeds and driving situations the full hybrid can alternate between the electric motor and internal combustion engine for propulsion.
Because the internal combustion engine appears to be working less than that of a conventional car you would expect the demand on engine oils for hybrid engines to be less, but in reality, the opposite is true.
Because the internal combustion engine in a hybrid is not operating all the time and is frequently stopping and starting, it runs at much lower engine temperatures most of the time, which means that in terms of lubrication, you need an oil that provides superior protection for cold starting where most of the internal engine wear occurs, because the oil has to circulate through the engine and coat the moving parts.
Frequent stop-starting is hard on bearings so having adequate protection for repeated cold starting is essential on a hybrid, so regular oil changes are very necessary and OEM service recommendations must be followed.
There is also an issue with condensation as well isn’t there? Can you explain a little about this?
JS: When an internal combustion engine is operating at colder temperatures, another side effect is a build-up of water via condensation which leads to oxidation and corrosion.
Therefore, for a hybrid gasoline engine, you also need an oil that is designed to work in an environment where you have greater condensation. When you look at it in detail, hybrid internal combustion engines require oils with specific formulations and protection properties.
Also, on the battery-electric side, you need to consider heat transfer properties and wear on the transmission, so if you plan on servicing hybrid and/or electric vehicles, these are all things you need to consider when it comes to fluids and maintenance.
Development of E-fluids technology
Can you tell us how Shell’s research and development regarding E-fluids has evolved regarding advances made in EV technology?
JS: Several years ago, we started working on developing E-fluids and E-greases in our conventional laboratory and E-facility alongside the work on hybrid engine oils.
We’ve also been working on transmission fluid development and testing as well as battery research and testing. As a result of all this, we’ve created a specific energy centre at our R&D facility in Germany where we focus on battery performance and testing as well as charging options for the batteries, including some that provide higher power than what is currently available on the market.
There is also research happening regarding the interaction between the vehicle, the charger and also the electrical grid. Another aspect of this research is collaborating with OEMs and battery suppliers, which is absolutely key to making it all work.
What are the key aspects of EV operation where good lubrication and protection are essential for optimum performance and reliability?
JS: There are several factors to consider. For the electric-drive units, you need a thermal fluid with very good heat transfer capability.
Because corrosion is one of the greatest enemies of electric motors you can’t use conventional water/ethylene glycol coolant, instead you require specifically formulated fluids with effective heat transfer properties that are compatible with an electric drivetrain.
You also have to consider that electric motors operate at very high rpm so for the transmission in these types of vehicles, you need to ensure the fluid has adequate wear protection to withstand these operating conditions.
When it comes to E-greases, besides protection, there are also specific things you need to consider like low noise characteristics, since in a battery electric vehicle (BEV) there is no internal combustion engine, meaning that consumers can be exposed to a whole range of different sounds they previously did not experience, so these are all things you need to consider.
Shell’s approach to thermal efficiency
A major issue with some early EV battery systems was keeping them sufficiently cool. What’s been Shell’s approach to thermal efficiency to tackle this issue?
JS: There are really two points to mention here. The first is battery testing via immersion cooling that allows us to bring coolant into the battery and test it.
At our R&D facility, we have also built up data simulation models so we can simulate various conditions including heat transfer to monitor battery performance and longevity. The second aspect concerns collaboration and working with OEMs and battery suppliers to maintain optimum battery efficiency and performance.
A good example is using immersion cooling for lithium-ion batteries that are powering many of the current battery-electric vehicles on the road such as those from Tesla.
E-transmission fluid development
Can you tell us a little about E-transmission fluid development and what are some of the key things to consider for optimum driveline performance and reliability from an E-transmission standpoint?
JS: As this technology evolves, one trend we are likely to see is combining fluids for both the transmission and the battery pack.
This means we need to combine maintenance and wear protection needed for the E-transmission and also must consider electric “compatibility” for the fluid, so it contains properties that protect but do not damage electrical components.
A good example is not having sulphur in the E-transmission fluid since it corrodes copper which is used extensively in electrical components. As a result, in developing these combined thermal E-fluids we’ve had to adopt new additives to protect the driveline.
Testing and development in motorsport, such as Formula-E and collaboration with OEMs such as Mahindra have been extremely useful in developing these formulations that provide good thermal properties/temperature control, good solar conductivity and oxidation protection.
Benefits of Helix Hybrid
Can you explain Helix Hybrid and some benefits of using it for aftermarket service shops?
JS: For aftermarket service shops, they must educate their customers who drive hybrids.
Going back to an earlier question it’s important that vehicle maintenance is performed regularly and specific oils like Helix Hybrid that have good cold starting and corrosion protection are utilized. It may seem counter-intuitive at a glance, but when you actually think about the number of times the gasoline engine switches on and off in a hybrid during operation, having oils with these properties is essential.
It’s also important to note that cold starting behaviour also impacts fuel economy, which is a key reason why consumers purchase hybrids, so this is something aftermarket shops should also consider when educating their customers.
Key elements of effective E-grease and E-fluids
Given the high rotational speeds of electric motors and friction emissions, what are some of the key elements an effective E-grease needs to ensure these motors can perform day in, day out with minimal wear on the bearing surfaces?
JS: Greases are even more complex than lubricants because not only do you have the base oil and additives, but also a third component—thickeners.
This provides both opportunities and challenges. If we think about a typical internal combustion engine, its maximum revolutions per minute are usually between 6,000 and 7,000 rpm. In our test facilities, we are testing e-greases that need to withstand up to 30,000 rpm and extremely high temperatures—beyond what traditional greases can cope with.
So, when you’re developing an E-grease, these are things you have to consider. That’s why having the right thickeners is so important since at very high temperatures electricity breakdown can lead to deposits, which quickly shortens the life of electric motor bearings.
You also want to consider the noise factor and to minimize that you want a very “clean” grease with low noise properties.
From a general perspective, in terms of service intervals, what do you recommend for E-fluids to ensure optimum EV reliability and operation?
JS: It is always a good strategy to look at the recommended maintenance intervals from respective OEMs and that goes for aftermarket service shops as well as dealers.
Ultimately, for a consumer, a vehicle is typically the second most expensive object they own and for it to provide good, reliable and long-term mobility, they need to look after it.
Our suggestion is to follow the OEM recommendations but also for service providers to understand how their customers drive, how often they drive and plan maintenance schedules accordingly.
Future of carbon-neutral lubricants
Is there anything else you’d like to mention?
JS: Currently, there is a big push toward becoming carbon neutral on the lubricants side both for transportation and also industrial applications.
At Shell we are looking at this from a cradle to grave perspective. Focusing not only on the energy-sourcing but the manufacturing, transportation to the customer and also the end-user impact.
This is a big step and in Europe, is now moving forward which is good news. Before, most of the focus has only been on CO2 emissions during the manufacturing or possibly the transportation stage and not focusing on the end-user.
Having a complete product lifecycle approach to reducing CO2 output is essential if we are to achieve carbon neutrality when it comes to lubricants.