Automotive: Fuel economy and emission controls challenge diesel fuel filtration - Part 1

5 min read
Figure 1: There are wide regional differences in meeting diesel fuel filtration requirements.
Figure 1: There are wide regional differences in meeting diesel fuel filtration requirements.
Figure 2: Reducing emissions is a global priority.
Figure 2: Reducing emissions is a global priority.
Figure 3: Before and after fuel conditioning (Courtesy of Algae-X).
Figure 3: Before and after fuel conditioning (Courtesy of Algae-X).

Global and local factors

According to Andrew Shepard, director of global market management in the engine and industrial filtration division at Hollingsworth and Vose (H&V), 22% of global energy consumption and over a quarter of global carbon emissions are the result of transportation and, as a result, the world’s governments have implemented tighter fuel economy and emission controls. “Examples like the new 54.5 MPG fuel economy requirement for passenger cars in the United States, becoming law in 2025,” Shepard explained, “and a first of its kind fuel requirement for heavy trucks in 2018, have put increasing pressure on liquid and air filtration requirements.” While reducing emissions is a global priority, actual filtration requirements follow different regional needs. Shepard added: “For example, within the dynamic diesel fuel filtration market segment, regional factors that are impacting filtration requirements include local emission requirements, type and percentage of biofuels, as well as particulate and water concentrations within the local fuels. Meeting these diverse regional differences requires a broad product portfolio, unique development tools and local technical expertise - Hollingsworth and Vose has all three.”

Filtration media

According to Shepard, H&V’s broad portfolio of different media addresses all particulate and water removal requirements to meet the legislative requirements of Euro VI, US Tier IV and China IV. H&V has refined its conventional wet laid cellulose products to achieve high efficiencies cost effectively, higher dirt loading capacities and increased lifetime as required through most of this range. The company’s highest performance glass fibre fuel media enables greater than 99.5% efficiency at 4μm rating with associated high permeability and capacity. “We design and produce our own glass fibres,” Shepard explained, “allowing us to specify unique fibre diameters and diameter distributions to tailor to each filtration need.” As market interest has grown for a glass-free solution to address potential health, recyclability and fuel injector scoring issues, H&V has invented new high-performance, glass-free media. Its synthetic composition - a combination of different forms of nano and submicron fibres into a layered media composite - contains no glass microfibres. “The media achieves greater than 99.5% efficiency at 4μm rating with correspondingly high capacity and permeability to reset the standard for the most demanding applications,” Shepard said. “These newest products address the desire in many markets for higher efficiencies and increased filtration lifetime in a glass-free media to meet future emission requirements while also providing a low market-leading pressure drop,” he added.

Hollingsworth & Vose innovations

Development and optimisation of synthetic nanofibre production is one of H&V’s key initiatives. Shepard explained: “Our particulate optimisation model works in tandem with an ability to form submicron fibres and craft web formations according to specific design requirements.” The unique geometry of these small diameter fibres can change the traditional properties of a product. H&V works closely with filter manufacturers to optimise these composite constructions for specific filtration applications. The need for both clean and dry fuel has become a key requirement for internal combustion engines to meet both current legislation and engine performance levels, and nowhere is this more important than in diesel fuels. Water in diesel can cause cavitation, hydrogen embrittlement, loss of lubrication and corrosion, resulting in engine damage and reduced lifetime. In Western Europe the maximum admissible content of water in fuel is 200 ppm (according to DIN EN 590). The concentration of water in diesel fuel may exceed this maximum value significantly in other regions with high humidity and where large daily temperature differences exist. Shepard told us that H&V is able to cater for these environmental variations by manipulating resin type, fibre geometry, manufacturing processes, and composite layering. “As a result,” Shepard explained, “we can develop the required level of water shedding or coalescing that is specific to the particulate micron rating and desired design of our customer’s filter.” “Our scientists work closely with regional leaders,” Shepard went on to explain, “and they draw from broader global experience to develop products that best fit local requirements.” The company’s newest Tier IV products offer greater than 99% efficiency at 4 μm rating and greater than 200 g/m2 of dust holding capacity (DHC). For the Chinese market, H&V’s China III products are designed to provide 98.5% efficiency at 4 μm rating with greater than 130 g/m2 DHC. H&V’s ongoing fuel platform optimisations for Euro VI and China IV include glass-free media at greater than 99.5 % initial efficiency and 4 μm rating, a market-leading low pressure drop, greater than 250 g/m2 DHC, and an extremely high (over 60 minutes) ISO 4020 lifetime. Shepard added: “Our worldwide technology and marketing experts understand the complexity of regional needs while drawing on a broad global footprint of technical research facilities and manufacturing mills across the Americas, Europe and Asia to meet our global customer requirements.”

Fuel conditioning technology

Among the product lines from AXI within the automotive sector are particulate filtration and water separation technologies, essential components for diesel fuel systems, but an additional focus of the company is on fuel conditioning before in enters the vehicle. Bill O’Connell, president of Algae X International (AXI), explained: “Changes in the production of fuels, including catalytic cracking and reduction of sulphur, have negatively impacted on fuel stability. This in turn results in sediment formation in the fuel, causing short filter life, poor combustion characteristics – loss of power, excessive particulate emissions, damage to injectors and fuel pumps, and dirty fuel tanks.” Fuel conditioning reverses the processes through which these sediments form, thereby improving fuel quality. Filter life is extended, engine performance is optimised, emissions are reduced, and the frequency and intensity of engine maintenance is also reduced. “Only a small percentage of our business is in the automobile, truck and transit bus markets,” O’Connell added. “Automated fuel maintenance systems and tank cleaning systems are our primary focus in the automotive industry, along with high performance chemical processes.”

Algae-X innovations

The Algae-X Fuel Conditioner is AXI’s most innovative product line. “Its importance,” O’Connell went on to explain, “is in dispersing insipient sediments in the fuel, essentially restoring optimal fuel quality, therefore resulting in longer fuel filter life, improved combustion, better power production and reduced emissions, longer injection system component life and clean fuel tanks. Basically, it saves money and improves the performance of the vehicle.” Figure 3 shows the fuel quality before and after fuel conditioning. We asked O’Connell about research and development and he told us that his company’s focus is on engineering larger scale fuel transfer and delivery systems, alongside continual research into the development of fuel additive packages. A significant driver affecting the filtration and separation industry is the growth of emerging markets. Whilst the global automotive market continues to grow, emerging markets such as China have increased market share substantially over the last 10 years. We asked O’Connell whether there is any evidence of a shift in filtration design and production away from North America and Europe to where the vehicle production levels are increasing. O’Connell replied: “Our focus is the continued expansion into the automobile and trucking markets throughout the Caribbean, Latin American and African regions where poor fuel quality is the norm. We do see many new companies emerging in China, India and Indonesia.” We went on to discuss other issues that are important drivers of developments in diesel filtration, including legislation to reduce emissions, increasing health concerns, energy efficiency improvements and the sustainability agenda. “We agree with many efforts to improve energy efficiency and reduce emissions,” O’Connell replied, “but we have major issues with biofuels as they are inefficient use of resources. For example, eight gallons of water are required for each gallon of biodiesel produced, and the product yields only about 90% the BTU values of hydrocarbon-based fuels. Additionally, the bio-components cause expensive maintenance and storage issues.” It would appear though that these drivers seem to be opening up new market opportunities. For example, passenger car technology developments are showing a trend from hybrid petrol/diesel to electric vehicles with the development of hydrogen fuel cell technology starting to gather pace. We asked O’Connell whether these developments are likely to displace diesel engines more than petrol ones and whether they provide any longer term opportunities for new innovations in filtration technology. “It is unlikely that any of these technologies will displace hydrocarbon-based fuels”, said O’Connell. “They are simply not cost effective, are inefficient, and cause new types of delivery, storage and maintenance problems.” “Our core focus is in fuel optimisation technologies – primarily applied physics and chemistry solutions, along with continued development of traditional technologies in filtration and water separation. Changes in injection systems mean that fuel filtration needs to be increased down to 2μm rating micron levels to prevent damage to expensive injection components. This is existing technology and will necessarily be increasingly applied to automobiles.”

Read Part 2 of this article