Recent news of an updated legal interpretation to the regulations imposed on glider kit makers has acted as another reminder of the strides the industry has made in increasing fuel efficiency while reducing emissions.
From a practical standpoint, the introduction of the high-pressure common rail (HPCR) system has forever changed engine technology. From the perspective of Donaldson Filtration and other filter suppliers, the changes have meant significant advancements in filtration technology to keep pace.
Clean fuel has never been more important for proper equipment maintenance and minimized downtime. The sophistication of today’s vehicles requires higher fuel cleanliness to meet the demands of precision-designed fuel system pumps and injectors. The HPCR system used in today’s low-emission engines provides higher pressure and better burn, but the downside is the fuel systems are much more susceptible to damage from contaminants 20 times smaller than the diameter of a human hair. Contamination can result in poor engine performance, lower efficiency/fuel mileage and ultimately engine failure.
Prior to the last emissions requirement update in 2010, the industry focused on removing particles of 7 microns or larger. With today’s tighter tolerances since the regulation took effect, we’re removing particles that are only two to four microns and larger.
Today, the first symptom of poor fuel quality could be plugged filters on bulk storage tanks or trucks. Instead of assuming that it is a problem with the filter, it may be time to look at the source: fuel contamination.
However, keeping diesel fuel clean is more complex because of higher concentrations of water emulsions in fuel and organic contaminants that can foul the system. Fortunately, advancements in fuel filtration are helping to meet growing fuel cleanliness requirements of modern diesel engines for increased performance.
Water hazards
Water is a particularly challenging contaminant in fuel. It can reduce lubricating qualities and cause injector seizure and engine damage. Water in the fuel supply is a significant hurdle in achieving the best performance and can also cause fuel filter plugging, injector deposit buildup, fuel instability and even bacterial growth in onboard and bulk fuel tanks. Most engine manufacturers require strict fuel water separation before the fuel reaches the HPCR fuel system.
To achieve more reliable fuel-water separation, primary filters are transitioning to advanced filtration technology referred to as coalescing filtration. This style of filter features multi-layered filter media and multiple stages of filtration and separation to collect finer water droplets into larger ones so that they can be more easily removed from the fuel.
Biodiesel blends
The increased use of biodiesel blends has also put more pressure on filtration systems. While glycerin and other related glycerols — byproducts of biodiesel production — are in biodiesel blends, they won’t cause immediate problems as long as they remain warm and in liquid form. At low temperatures, however, glycerin assumes a solid, wax-like state where it can drop to the bottom of tanks, get caught in fuel filters and form sticky, corrosive engine deposits. Ultimately, these deposits can immobilize a fleet.
The exact blend percentage, temperature and water content can all affect how much glycerin a fuel can hold in solution. Once it precipitates, or comes out of solution, glycerin can negatively impact filterability in ways similar to excess additives and drastically reduce expected filter life.
To help mitigate this issue, Donaldson recommends operators look for blends with lower glycerin levels. Storage practices that keep the fuel clean and dry will also help.
Filtration technology
For fleet maintenance managers, it’s important to understand what goes into a modern fuel filter. In the past, cellulose was the “go-to” material for fuel filtration, and it evolved to incorporate micro-glass and other synthetics to achieve high efficiency in a single-layer media.
Today, advanced fuel filtration media formulations use more synthetics and synthetic/micro-glass formulations, and they rely on multi-layer structures to achieve high efficiency and long life by allowing effective storage of both hard and soft particles in the media. This is a key area of fuel filter performance differentiation. As the high-efficiency filter picks up more fine contaminants, what could have passed through a filter in previous years can now be a contributing factor to plugging today’s tighter filters. Proven media technologies like Synteq XP, used in Donaldson Blue fuel filters, address this by delivering a high level of efficiency and contaminant retention.
In addition to fuel filter media advances, fuel filtration solutions are engineered at the system level.
Today, it is very common to use a fuel filtration system that utilizes more than one filter, each with varying degrees of performance. Donaldson also encourages filtration upgrades at the bulk storage stage to head off contamination and fuel quality problems before they reach the fleet.
Real-life conditions
As the filtration industry looks to the future, we are continuing to evolve and refine the technology. Advancements are also being made to ensure that filtration research and development takes into account the dynamic environments in which the products ultimately operate. This includes factoring in engine vibration, fuel pump pulsations and varying fuel flows, among other operating conditions.
The three critical performance objectives of efficiency, capacity and retention and pressure drop must be delivered by filters under these dynamic and often severe conditions. Testing, which represents performance under real-world dynamic challenges, has become a mainstay request from customers using HPCR systems and is becoming an important tool to differentiate filter technology and allow customers to make the best decision on how to protect fuel injection systems. Fuel filtration is on the front line of your defense against downtime and operational expenses.
Contaminants in diesel fuel such as hard particles, dirt, water and organic soft particles can have a wide range of impacts to equipment, some of which can have profound issues relating to warranty and the total cost of ownership.
Jason De Guelle is the Product Manager of Engine Liquid Filtration solutions at Donaldson Company. During his 13 years with Donaldson, he has worked on exhaust emissions technology, chemical process filtration, air intake systems and engine fuel, lube and coolant filtration. Jason earned his Bachelor of Mechanical Engineering degree from the University of Minnesota-Twin Cities.
