B Y W A LT E R K U D L I C H
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urrent and future legislation is forcing original equipment manufacturers to find ways to improve fuel economy and reduce carbon dioxide emissions across their vehicle fleet. Thus, improved fuel economy will remain the key driver for future powertrain
designs. In the past, engine oil additives contributed to fuel economy in two ways. First, additives supported the development of engine designs that improved fuel economy without compromising performance while maintaining durability over the oil drain interval. Second, new additive technologies and engine oil formulations, tailor-made for oil companies and OEMs, improved fuel economy in their own right. Today, the potential remains to improve fuel economy even more by moving to low and ultra-low viscosity oils and by redesigning hardware. The optimum approach is a co-engineered solution where engine and lubricant are developed in parallel. However, limiting the approach to fuel economy alone is not sufficient. A holistic viewpoint is needed that considers all performance requirements of future engine oils, keeping in mind that performance cannot be defined based solely on chemical limits.
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Meeting the Regs The industry faces major challenges in the next decade and beyond. All regions are broadly driving down emissions at a nominally similar rate. However, while the preceding decade saw about a 25 percent reduction in absolute carbon dioxide emissions, a 40 to 50 percent absolute reduction is projected for the next decade. The European Union has the most stringent requirements for fuel economy today. Car makers that fail to meet carbon dioxide limits after 2020 will face massive penalties. While carbon dioxide limits for commercial vehicles are still under development, the system for trucks will go much further than for cars, controlling every unit and component that impact fuel economy. Different regulations and consequences for violations are under discussion for the key regions of the EU, United States and China. For example, China will probably take the initiative in major cities and might only allow full electric vehicles in certain urban areas. Formulating FE Additives Lowering lubricant viscosity is one measure being taken to reduce fuel consumption. However, the downside of this approach can be higher wear. An example is a field trial of a lowviscosity gear oil in 10 trucks totaling
more than 500,000 kilometers. The gears showed increased wear with thinner oil, although part condition still met OEM requirements. Ideally, hardware can be redesigned to compensate for the use of lower viscosity oils, but reformulation using additives at higher treat rates can also help offset the effects of lower viscosity. But OEMs and additive or oil companies have to work hand-inhand from the start of a new development project to ensure reliable performance. An example where this approach was followed successfully is Mercedes’ latest generation automatic transmission. Because the company worked closely with the lubricant supplier, it is able to use by far the thinnest ATF on the global market, gaining a 1.5 percent fuel economy benefit from just the fluid in the new hardware. It is a simple concept to grasp that lower viscosity equals fuel economy benefits, but the ability to both measure this value and to tailor the fluid to the engine and vehicle platform is more challenging. For instance, Afton testing showed a 1.8 percent fuel economy benefit for a specific vehicle using an SAE 0W16 engine oil. However, in a different vehicle, moving to lower and lower high-temperature high-shear viscosities showed the opposite effect. Lower viscosity is not a bottom-
JUNE 2017 • LUBES‘N’GREASES EUROPE-MIDDLE EAST-AFRICA