by Hank Hogan

Truck and bus OEMs face a series of short- and long-term fuel-related problems, according to Anders Röj, and it will take a global and synchronised effort to solve them. As a coordinator for fuels-related issues within the Gothenburg, Sweden-based Volvo Group, Röj is in a position to come up with possible solutions.

Röj outlined these issues at the UNITI Mineral Oil Technology Congress in Stuttgart, Germany, in April. His presentation covered heavy-duty vehicle emissions regulations, standardisation and international harmonisation of fuel quality, cold flow robustness and filter blocking, as well as fatty acid methyl esters (FAME) biofuel blends.

The issues are inter-related, yet fundamentally dissimilar, he said. “These issues are of somewhat different natures: short and longer term technical ones, administrative and harmonisation issues and cost associated with fulfilling legal obligations,” Röj said.

The short and medium term priority is the trucks and busses currently on the road and those about to enter the market, he said. These face steadily more stringent emission requirements, such as the more than 10-fold drop in diesel particulate matter and NOx mandated in 2013’s Euro VI, compared to pre-Euro I in the early 1990’s.

Achieving these targets while meeting customer expectations on vehicle performance can’t be done solely through engine and lubricant innovations. “The fuel is an engineering element, an essential part in the engineering process,” Röj said.

He also pointed to European legislation and standardisation process as a good example of how to tackle this issue. Regulations and standards have improved fuel quality in lockstep with more stringent emissions. For instance, sulphur in diesel fuel, which at one time could be in the thousands of parts-per-million (ppm), has been ratcheted down to less than 10 ppm. This, in turn, enables the use of efficient particulate and NOx emission control technology.

But, there are other fuel issues that are still not fully resolved. For example, Röj noted cold operability, particularly for fuels with FAME content. All aspects of the problem are not fully understood, although it seems to be related to quality of the biodiesel and also to the use of high levels of additives.

While the source may not be clear, the impact is: cars, trucks and busses that won’t start or fail to operate because of filter blocking. For OEMs like Volvo that can be problematic, particularly because of government mandates that require higher percentages of biodiesel in petroleum diesel. The industry is working on the problem but there is still no definitive solution.

The push for higher biodiesel blends, such as in Brazil, is being driven by the desire for more sustainable transport; thus, OEMs are exploring alternative fuels. Volvo, for instance, is looking into methane and dimethyl ether fuels, with both being either bio- or fossil-based. These will require new engines and vehicle arrangements.

That is not the case for synthetic diesel produced by a Fischer-Tropsch process and hydrotreated vegetable oils. These fuel alternatives are “drop in”, so they can be used in engines on the road today. These fuels are already available commercially. They are also closer than other alternatives to the cost of existing fuels.

“In the short and medium term, the second path – including sometimes hybridisation or electrification – will be the more likely one [chosen],” Röj said.

Röj also discussed recent regulations from CEN, the European Committee for Standardization, about paraffinic diesel fuels, like hydrotreated vegetable oils and ,gas-to-liquids (GTL). Increasingly, such fuels are being used in stand-alone applications, where they are not blended with anything and thus make up 100% of the fuel.

In those cases, there has to be a standard that governs these fuels and their parameters. A standard also would gain vehicle manufacturers acceptance of such fuels. EN15940, which covers paraffinic diesel fuels, was recently finalised.

When used as a blend component, such fuels will be governed by relevant diesel fuel standards, such as EN590 and ASTM D975, he said.

There is an ongoing requirement for regulatory clarity and consistency, which is being addressed through the Worldwide Fuel Charter, Röj said. The charter, which is being updated, categorises fuels according to market type. Markets with advanced emissions standards in place are recommended to use the most advanced fuels available in the market. While the charter is purely a recommendation from OEM groups such as ACEA, the European automobile manufacturers association, and JAMA, their Japanese counterpart, it’s an example of a step in the right direction, according to Röj.

“Longer term the over-arching priorities are related to having good, international global systems for fuel standards and related emissions and durability requirements,” he said.