In Australia, the landscape of biodiesel consumption has undergone notable changes over the past half-decade, reflecting a broader global shift towards renewable energy solutions.

As a nation endowed with vast agricultural resources, Australia has seen a growing interest in biodiesel to reduce greenhouse gas emissions and enhance energy security. Policy frameworks, such as the Renewable Energy Target and Australia’s bio energy roadmap, have played pivotal roles in encouraging biodiesel production and consumption.

Technological advancements have also been instrumental in expanding Australia’s biodiesel capacity. Innovations in feedstock processing, such as the use of waste oils and fats from the food industry, have made biodiesel production more economically viable and environmentally sustainable.

Users of the new diesel engine reported their fuel filters were clogging much faster than expected. Scanning electron microscopy (SEM) analysis showed the filters were caked with ultra-fine, gel-like deposits in the 1 to 2 μm size range.

Unforeseen Consequences

The changes in biodiesel blends occurred rapidly and came with a consequence no one anticipated: premature plugging of fuel filters. This was the case for a global original equipment manufacturer (OEM) that launched a new engine around the same time these new blends hit the market.

Users of the new diesel engine around the world reported premature clogging of fuel filters that resulted in service intervals 30 to 50% shorter than expected.

The filters were caked with an unusually high amount of soft, gel-like deposits of an ultra-fine (1 to 2 μm) nature. Chemical analysis revealed the deposits were metal salt carboxylates. But where did they come from?

What happened next can only be accomplished through filtration science: the collective blend of analytical expertise and laboratory capabilities of the Fleetguard team of engineers, chemists, biologists and specialists.

Chemical analysis by Fleetguard revealed the soft contaminants plugging fuel filters were metal salt carboxylates. Carboxylates are known contributors to the formation of soaps, which are insoluble in diesel fuel and stick to filter media, accelerating plugging.
Chemical analysis of the source fuels found no spike in carboxylates, however, suggesting they may have been forming in the engine.

Discovering the Contamination Source

Working closely with the engine OEM, Fleetguard collected fuel samples from multiple locations globally to determine if the contaminants came from the fuel itself.

“None of the fuel samples contained a significant presence of carboxylates. That led us to wonder if the contaminants formed in the engine,” says Matthew Gillard, technical specialist at Fleetguard.

After running fuel samples through test cells that recreated engine and fuel conditions, Fleetguard’s specialists confirmed the carboxylates were indeed forming within the engine, under the high temperatures and pressures of the high-pressure common rail (HPCR) fuel injection system.

Then, uncombusted fuel — containing the newly formed carboxylates — was recirculated back through the fuel system.

Uncombusted fuel containing carboxylates that formed inside the HPCR fuel injection system was recirculated (blue path) back through the fuel system and filters, causing them to clog prematurely.

Increasing Filter Capacity for Real-World Conditions

Now that the team understood what was happening, it was time to determine how to modify the filter designs to address the issue.

“Our filters targeted and captured the particle sizes of contaminants present with a very high efficiency,” Matthew says. “What we discovered, however, is that the filters lacked the capacity to hold the volume of soft organics created from the new biodiesel blends”.

The fuel filters originally supplied by Fleetguard for the engine incorporated a nanofiber technology called NanoNet to protect engine applications with tighter component tolerances from hard contaminants such as sand and dust.

After evaluating many different combinations of media, Fleetguard filtration experts decided to add a proprietary glass layer that would hold the high volume of soft contaminants they were encountering and still meet the OEM’s original service intervals.

“Testing validated our approach,” Matthew says.

“The redesigned filters provide seven times greater life and more than double the carboxylate removal efficiency compared to our original filter design.”

Fleetguard also tested its redesigned filters against a competitor filter the OEM had been considering. Initial testing indicated the competitor filter would provide longer filter life than the original filter. Further testing, however, showed the competitor filter was less effective at capturing contaminants, accounting for its longer service life.

Those tests demonstrated the original filter design removed more of the soft contaminants than the competitor’s filter would, Matthew says.

The results of these tests gave the OEM confidence the new filters would meet their specified maintenance interval.

The response by Fleetguard also demonstrated the ability to apply filtration science quickly and effectively to tailor technologies to suit OEM needs. Shortly afterward, the OEM awarded Fleetguard additional business as the sole provider of fuel filtration technologies on a significant part of its engine portfolio.

Tests showed redesigned media would extend filter life by more than seven times over the original design. They also showed that the new filter media — and even the original filter design — is significantly more efficient at removing the soft carboxylate contaminants than a competitor’s filter.

Filtration Science Protects Your Investment

Diesel engine OEMs and equipment operators encounter new challenges every day. You can be confident that your engines and equipment will go further — no matter the circumstances — with the protection of filtration science.

Because you need to safeguard the investments you make in your equipment, Fleetguard invests in research and develops superior filtration products that extend the limits of performance.