Nanofibers Offer Finer Oil, Air Filtration, But Some in Maintenance Question Value
This story appears in the Jan. 30 print edition of Transport Topics.
Nanofiber technology, already used in premium fuel filters, also is appearing in oil and air filters to help prevent maintenance problems on modern truck engines. Although nanofiber media offer improved performance, it comes at a cost.
Some maintenance managers aren’t convinced that finer filtration justifies the additional expense over conventional cellulose filters. Others are embracing nanotechnology as heavy-duty diesels run ever-tighter clearances to meet 2017 and future greenhouse-gas regulations.
In September, Cummins Filtration introduced the NN series to its Fleetguard product line, naming the new nanofiber media NanoNet, with the first application on the Cummins ISX/X15 engine. In the same timeframe, Baldwin Filters Inc. launched its next-generation, highly engineered media in the BD50000 for the Cummins engine.
Other examples include Donaldson Co.’s premium Blue line of lube filters, featuring Synteq XP media, another proprietary name for highly engineered synthetic media. Amsoil’s range of EaO filters also features nanofiber media.
Nanofiber technology also is increasingly found in air filters, where the ability to filter down to 2 microns with a far lower pressure drop than conventional paper or cellulose filters is adding life and performance to heavy-duty diesels.
“They do provide higher initial and overall efficiencies when tested in the lab using standard test contaminants,” said Roma Fatima, lube product line manager for Cummins Filtration. “It is typical for fine fiber media to allow [80% to 90%] less contaminant to reach the engine compared to standard cellulose media.”
They also offer enhanced service life, said Steve Carter, manager of aftermarket air applications at Donaldson Co., a supplier of filtration products. “Donaldson actually offers a ‘Twice the Life’ guarantee for Donaldson Blue filters with Ultra-Web media, when used in over-the-road truck applications.”
Nanofibers are not new, nor are they particularly new in vehicle filtration: The Abrams M1A1 battle tank has used nanofiber air filters for more than 25 years.
Nanofiber use is a trending technology for engine filters, Carter said. “However, it’s not new to Donaldson.”
“We have been providing nanofiber, or fine fiber, media in engine intake air filters for over 20 years for both off-road and on-road applications,” Carter said.
“The first commercialization by Donaldson of fine fiber media was over 25 years ago in industrial applications, so we have extensive experience in this area and in how best to apply it to provide the optimum filtration solutions for today’s trucks.”
The nanofibers are extremely fine — about 1/500 the diameter of a human hair. In an oil filter, they are combined into a mat that is supported most often by a regular cellulose filter matrix or as a separate filter stack. With the latter, the nanomaterial can be fashioned as a bypass filter that can take out particles down to 1 to 2 microns while the cellulose fibers will remove 98% of the 20-micron particles on each pass through the main filter.
“Fleetguard uses a unique lamination process that pairs the company’s NanoNet and StrataPore media together to create a single filter element,” said Brad Long, senior engineering technical advisor at Cummins Filtration. “This media combination yields a perfect balance of protecting the engine from larger damaging particles and removal of the finest particles through oil recirculation.
“It’s designed to optimize capacity and service life and further reduce flow restriction, allowing the latest generation of diesel engines to operate more efficiently with less parasitic power loss, which can lead to better fuel economy and lower CO2 emissions.”
U.S. Xpress Enterprises is acknowledged as an early adopter of new technologies.
“We have converted over most of our engine makes to an NN-rated filter about a year ago,” said Gerry Mead, senior vice president for maintenance at the Chattanooga, Tennessee-based carrier, which ranks No. 19 on the Transport Topics Top 100 list of the largest U.S. and Canadian for-hire carriers. “We can say that we actually saw a change in oil samples that proves the claims. Our TBN, or total base number, has held at more acceptable levels, which obviously has an effect on wear and fuel economy,” Mead said.
“We will be looking at filter capacity here in 2017, especially with increasingly fine filtration as more wear debris is being captured,” he said. “We want to ensure we still are properly caring for our engines and making appropriate decisions on life cycle.”
But Doug White, maintenance vice president at Dunbar Armored, does not see the value of the new nanotechnology for oil or air filters.
“If fleets are using restriction gauges, they will still replace the air filter at 18 to 20 inches of restriction, anyway,” White said, referring to the air restriction gauge that measures the pressure drop across an air filter. The reading rises as the filter loads up with dirt and dust. It also may be a simple color-change gauge.
Either way, a filter change will become necessary as indicated on the gauge. The units of measure are inches of water — and 18 to 20 inches for a water gauge is about 0.7 to 0.8 psi.
Disturbing the air filter as little as possible during its useful life is the recommended practice. Every time it’s removed, there is a danger of some residual dust falling off the filter and finding its way into the engine.
“I suspect that there are fleets out there that still allow the service technician the latitude to replace the air filter when it looks ‘dirty,’ so they would not see any benefit to the new and improved filter. They would just see additional cost,” said White, who also is general chairman of American Trucking Associations’ Technology & Maintenance Council. “And with the age of our equipment, I struggle to make the additional dollar-cost work.
“It may be that, in the future, it becomes necessary on the next generation of engine, but I do not see the benefit in our fleet at this time.”
Darry Stuart, limited time maintenance executive and principal of DWS Fleet Management, shares those sentiments.
“I think conventional filters do an adequate job, providing as they do 98%-plus removal of harmful contaminants,” said Stuart, who is a past general chairman of TMC. “From the research I’ve done, it’s hard to justify the additional expense that these filters cost, and I would never let a technician service an air filter except by restriction. I even have a field on my service sticker for this purpose.”
U.S. Xpress’ Mead, however, is adamant that the nanolube filters are a great investment.
“The [return on investment] is in the prevention of failures,” he said.
With numerous EPA regulations, “more and more contamination is being forced into the oil,” Mead said. “This leads to premature failures in all areas — aftertreatment, bearing, turbos. [NanoNet Designs] filter technology, coupled with the correct oil choice, has an astounding effect not only on mpg but overall maintenance in general.”
Long, of Cummins, maintains that depending on the quality of oil used, its NanoNet “is capable of longer service intervals, which help fleets reduce operating costs on replacement filters over the course of an engine’s life.”
