Longer oil drains in China
As formulators look to meet consumer and OEM demands for lubricants that offer protection to their heavy-duty diesel engines over longer drain intervals, Infineum technologist, Haiyang Jiang, discusses the challenges presented by the complex conditions in China.
Deciding when to change the oil in a heavy-duty diesel (HDD) engine is quite a difficult but important question because it significantly affects fleet operational costs. Longer intervals are clearly inviting to the fleet operator, as they strive to maximise profits, as their trucks can stay reliably on the road for longer. But there are real trade offs that must be considered. Stretch the intervals too far and there is a risk of shortening the operating life of the engine and incurring the cost of early-unscheduled engine overhauls or even vehicle replacement. However, shortening the drain interval too much increases oil and maintenance expenses.
In today’s competitive market, engine manufacturers are working hard to increase sales. The introduction of advanced technology into their HDD vehicles, to cut emissions and meet reliability requirements, along with the promotion of ever-increasing oil change intervals are designed to increase the attractiveness of their products.
It is not surprising that both OEMs and end users are looking for oils that not only achieve extended oil drain intervals but also maintain robust engine performance.
The big question is how to meet these potentially conflicting requirements in the complex operating environment found in China. Different fuel types, inconsistent fuel quality, extremes of temperature and complex road conditions are some of the many variables that must be considered in the development of an effective extended oil drain interval lubricant for this market.
New longer drain lubricants will need to deliver higher levels of oxidation control, better TBN retention and improved soot-induced viscosity and wear control capability.
Infineum has been working to understand the complex nature of HDD oil degradation in China, and to find solutions for these challenges.
Understanding higher performance requirements
European ACEA oil sequences and API licensing standards are used to define engine oil quality in China. Although the performance requirements are clearly defined in the bench and engine test requirements, sometimes little help is offered to help marketers explain the difference between the categories. In ACEA for example, words like ‘excellent‘ vs. ‘effective’ or ‘very severe’ vs. ‘severe’ and even ‘significantly extended’ vs ‘extended’ do little to reflect the advantages E4 and E6 can deliver over E7 and E9.
Industry specifications provide a set of performance requirements that define oils that will run in today’s vehicles without causing problems.
Industry specifications deliver good quality lubricants that OEMs, oil formulators, oil marketers and end users can use confidently.
However, where there are additional challenges, some OEMs introduce additional requirements or tighter limits for specific parameters via their own in-house specifications. One example is the Scania Long Drain Field Trial (LDF), oils carrying the level 2 or 3 approval are considered to be extremely robust and able to provide extended drain performance. In our opinion, reaching this enhanced quality level is essential for lubricants designed for the Chinese market.
Challenges in China
One of the biggest challenges facing lubricant marketers looking at the Chinese market is the wide variety in the quality of diesel fuels. In the big cities China 5 fuels with low sulphur are available, but in other areas China 3 fuel and so-called ‘common diesel’ is still being sold. Vehicles could therefore be filled with fuels containing anywhere from 10 to 1000 ppm sulphur.
Fuel sulphur variability means that one of the key requirements for lubricants is the ability to deliver high and robust TBN for superior acid control.
However, designing a technology to meet or surpass the performance level demanded by the Scania LDF-3 field trial requires careful consideration of the full formulation approach. Many other factors must also be assessed to ensure extended oil drain engine oils continue to provide sufficient hardware protection:
- Controlling the deposits in turbochargers and pistons requires a good detergent system
- Maintaining excellent viscosity control means a highly shear stable VM is needed
- Delivering superior oxidation to minimise corrosion can be achieved with salicylate technology
Infineum has developed HDD technology to meet the requirements of the Chinese market using a careful combination of advanced chemistries. In bench and rig testing, the resulting SAE 10W-40 oil has demonstrated excellent performance against all these requirements.
Field trials confirm performance
Following the success of the initial tests, Infineum put the technology through an extended drain field trial. By running field tests it is possible to assess if the added performance measured in the laboratory is replicated in real world conditions.
The Infineum technology exhibited strong performance at a drain length of 120,000 km with minimal viscosity increase, excellent TBN retention and excellent protection against both mechanical and corrosive wear.
The resulting oil brings a number of benefits:
- Simplicity – one oil can be used across the entire fleet and will continue to meet warranty criteria
- Lower costs – Fewer oil changes and reduced service bills
- Peace of mind – Continued protection as confirmed by extensive field trials
Striking a balance
Extending oil drain in HDD applications is a careful balance. On one hand it is desirable to offer long drain capabilities to reduce operating costs for the end user. But, on the other hand, it is also essential that engine protection, engine cleanliness, low temperature performance and fuel economy are not compromised. Infineum long drain HDD technology has demonstrated excellent performance in a number of properties vital to the reliability of extended oil drain engine oil in carefully chosen engine and bench tests, which has been confirmed in field trials.
The potential to supply robust long drain lubricants for Chinese HDD applications presents an attractive proposition.
Using Infineum technology means lubricant marketers can be confident that their long drain lubricants will continue to deliver the required level of protection in the complex conditions encountered in this exciting growth market.