In the engine room
Approval processes for diesel engine oils vary according to the requirements of manufacturers and the many industry bodies. They can be time-consuming and costly but in the case of Shell Rimula R4 L CK-4, meeting the industry standard, is good news for transport managers, especially of mixed fleets.
It takes years to bring a new industry-wide specification into application. The process is complex as it involves various manufacturer’s requirements, months, and sometimes even years, of tests and data assessments, all of it coalesced through an industry body whose job it is to factor in market projections and technological innovations of Original Equipment Manufacturers (OEMs) and oil companies whose investments, will run into the millions of dollars.
Ultimately, the final result, which can take over a half decade to arrive at, yields an endorsement of product performance and reliability that gives customers, as they purchase oil products, peace of mind.
Bringing effective, low emission engine compatible oils for the new generation of heavy-duty diesel engines to market was one of the key factors in helping determine the specification of CK-4. After detailed consultation with OEMs and major oil companies, the American Petroleum Institute (API) produced CK-4, which is now the latest API diesel specification superseding the now more than 11-year-old API CJ-4 specification, as the new standard by which modern diesel engine oils, with their higher running temperatures and greater performance requirements in the areas of Oxidation Resistance, Shear Stability and Oil Aeration, would be tested.
According to Paul Smallacombe, Product Support Engineer, Viva Energy, changes to performance requirements for oils over the last couple of decades have largely been driven by emission standards for engines. Until recently, the focus has primarily been on reducing Particulate Matter and Nitrous Oxides (NOx), which are major contributors to smog and greenhouse gas effects. Moving forward there will be increasing focus on reducing Carbon Dioxide (CO2) emissions, which is most easily achieved by improving fuel consumption of vehicles. The focus until now on Particulate Matter and Nitrous Oxides has seen a reliance on exhaust after-treatment devices.
“When you run an engine there is always a small amount of oil that gets in the combustion process and ends up in the exhaust,” he says. “This means anything that’s in the oil formulation can potentially cause an issue with the exhaust after-treatment devices.”
Because oils are formulated from not only the base lubricating oil, but also from chemical additives, it is important for industry bodies to include limits on these chemical additives, particularly the so-called “SAPS” additives, which stands for Sulphated Ash, Phosphorous and Sulphur. Sulphated Ash relates to metallic components in the engine oil formulation, like zinc, magnesium and calcium that usually forms the detergent and anti-wear packages of the oil. It is this Sulphated Ash along with Phosphorous and Sulphur based ingredients found within engine oils that can pollute the after-treatment devices, reducing their effectiveness. In the last 20 years guidelines for emissions, limiting the amount of Particulate Matter and Nitrous Oxide heavy vehicles can release, by the kilometre, have become standardised across many international territories including the United States, Japan, Europe and Australia. This has produced a number of different technologies for emission reduction, two of the more common being Diesel Particulate Filters (DPF) and Selective Catalytic Reduction (SCR).
“For oil formulators that means that they have more limitations than ever on how much of these additives they can use in the oil, so it gets more challenging to formulate an oil,” Smallacombe says. “Parallel to that is the development of engine technology. Engines are more powerful and efficient than ever before, with longer oil drain intervals. All those things lead to increasing stress on the engine oil and requirements of an oil to perform at a higher standard.”
CK-4, as a recognised standard, is the result of realising higher performing products from newer technologies. There are other specifications, and many OEMs, according to Smallacombe, often have their own in place, which they need to meet for testing.
“If you look at a product sheet for one of the Rimula products, it isn’t just CK-4 that it is approved against, but a whole raft of other specifications which it meets. So there will be approvals for different manufacturers from Detroit Diesel, Cummins and Mercedes-Benz for example,” he says. “If an engine manufacturer is required by US legislation, to say, reduce Greenhouse Gas emissions, it will factor in tests using a technology designed for this by which the oil may need better oxidisation resistance for example. There will be different properties of the oil that might need improvement or will need to be at a higher level than the previous specification. So they might propose a laboratory bench test or an engine test. Then they’ll debate that and eventually come to an agreement as what those tests should be.”
It’s an expensive process. For CK-4 there are nine separate engine based tests to determine if the oil is up to specification. There are an additional number of bench or laboratory tests that might also need to be covered. Smallacombe estimates that Shell spends about $1.3 million on each of the engine tests for CK-4, developing its range of Shell Rimula products as candidates for approval. Every OEM specification, however, will not necessarily require the same number or breadth of tests.
“An OEM might use the CK-4 specification as a basis and have an additional requirement on top of that, for which the oil needs to pass in their testing,” he says.
“So you could go and get the CK-4 specification that might cost $10 million and then you can go to the OEM and they might require one or two additional tests. It could be a bench test, which is cheaper than a field test. The cost there could be at the cheaper end or more expensive depending on what additional tests they need on top of the CK-4. But most of the OEM specs use an industry body spec as the basis.”
Despite the costs and rigorous testing inherent in approvals some operators risk using non-approved derivative oils, blended from “off the shelf” base oils and an additive to meet the requirements without the quality control or testing regime afforded an officially approved product.
At present, Australia does not have the same licensing requirements as the US for claiming an API rating. Smallacombe says this allows some second tier manufacturers to cut corners.
“We typically find that the cost of the approvals means that the larger oil companies like Shell tend to do the work and spend the money to get the approvals. In the transport sector, smaller oil suppliers are reasonably common. You see them around enough to notice they are not just a small part of the market. The question is do they have the money to spend on getting their product officially approved?”
The issue soon becomes one of warranty. Most OEMs are in the habit of publishing a list of approved oils. According to Smallacombe if a product doesn’t appear on the list the manufacturer may deny warranty coverage. Because Shell is a vertically integrated company across the whole chain of supply, from exploration and production of crude oil, refining base oils and sourcing their own additives Smallacombe says they work closely with OEMs who are developing new engines, each step of the way, as they develop new oil formulations like Shell Rimula R4 L CK-4.
“It can get quite expensive if you don’t use an approved oil and you have an issue,” he says. “Where it falls down though is that there is no guarantee of quality control. Once a blender has purchased the additive and purchased the base oil, no one is coming back and checking how well you have blended it, what your quality control is like. Has it been tested, in any engine or lab tests? There’s no oversight of the quality, so, there’s always question marks around the quality. Products that have been officially approved can be tested to ensure they comply to the approved spec, which holds the manufacturer to account to meet those approvals into the future.”
This can lead to companies making claims, particularly around OEM specs, that they have met the requirements, by using terminologies such as ‘suitable for’ or ‘meets requirements of’ when they haven’t gone to the OEM and paid the money to be tested.
“They’re making the claim that it will meet the performance requirement of that industry standard or OEM specification”, Smallacombe says. “For the customer, however, there is no guarantee that it has been tested to guarantee that performance.”