"When I was a service engineer, I used to say, 'The way fuel filters look today is not how they are going to look in the future,'" says Steve Burnette, who is now mining and construction sales manager for Fleetguard. Today, fuel filters do indeed look different as filter makers address concerns created by advanced fuel injection engines, changing emissions regulations, new technological capabilities available for filter manufacturing, and a host of other issues.
Although the basic elements of fuel filtration have not changed greatly, improvements in monitoring, internal media, and improved drains contribute to the fuel-filtration system's overall ability to enhance engine performance.
Tighter emissions standards that demand lower-sulfur fuel have become a major issue affecting fuel filtration on heavy equipment. Lower sulfur content reduces lubricating properties in fuel just as heavy equipment engines are benefiting from refined fuel injection systems that increase performance.
"Compared to 1931, equipment today uses half as much steel and delivers 10 times the horsepower," says Greg Skeels, filter and fluids technology manager with Caterpillar. "That is why filtration and fluids are so important to what we do."
"Reduced lubricity in low-sulfur fuel can cause injector wear, which can lead to over fueling," he says. "When there was a pump in line, you could set it to compensate for over fueling. But you can't do that with new fuel injectors, and over fueling can eventually flood the machine." Or worse. Skeels says fuel injectors can cost $400 to $600 apiece, not including tune-up and adjustment of electronic systems.
Fleetguard has an innovative filter to address this issue. The FS 20000 Slow Release Lubricity-Enhancing Fuel Filtration System allows a lubricating fuel additive to be dissolved into the fuel as it passes through the filter. The FS 20000 is intended for use in Tier 2-compliant engines using Jet A, kerosene, winter fuel blends, or low-sulfur diesel below 50 ppm sulfur.
Particle size is another issue as the industry adjusts to GM's discontinuation of its AC Fine Test Dust, according to Nigel Atkins, market development manager with Pall's Strategic Business Development Group. While AC Fine Test Dust was available, particulate matter was measured in a relatively consistent manner, and fuel-filter manufacturers were able to rate their systems down to 1 micron or smaller using automatic particle counters.
When GM exited the test dust business, NIST instituted a new testing analysis method to classify a replacement dust and issued a new particle size distribution. This effectively meant that the same laboratory particle counters were now only able to resolve particles of approximately 4 micrometers, Atkins says. "Suddenly the same filter had a different micron rating on it."
While standards organizations address micron ratings, Atkins recommends paying close attention to claims of filter manufacturers and specifications from engine manufacturers. OEMs often use different issues of the same standard to retain compatibility with their existing test data, according to Atkins.
"This can make direct comparison between filter data sheets very difficult," he says.
With today's engines using injection pressures that can exceed 30,000 psi, Atkins says, "The systems require sophisticated pumps and injectors that are more sensitive to particles and water. The net effect is that water is more emulsified in the fuel."
Pall has developed a reverse-flow, depth media fuel-filtration system that uses the media to coalesce and separate emulsified water on a level that can be measured on a parts per million basis, according to Atkins. He says the system is used in Iveco equipment utilizing the "Cursor" engine developed in Europe.
Atkins says the filtration system is utilized on OEM equipment in North America where these Iveco engines are also used. Pall is currently talking with other U.S. engine makers to have them specify the system, which is based on technology successfully used in jet fuel handling and refineries. "We want to design for optimized-systems OEMs and do not plan on pursuing a generic after-market approach," he says.
Other filter makers have introduced new media to increase water capture. This is due, in part, to OEMs specifying fuel filters with increased water separation. Fleetguard, for example, has a new StrataPore synthetic filter media created through a melt-blown process that generates layers of polymeric fiber that can be adjusted for removal of specific particle sizes. It can remove more than 95 percent of both free water and emulsified water, according to Burnettte.
Donaldson also has developed new synthetic fuel media. Introduced last year, the advanced filtration system includes three layers of melt-blown media and a layer of silicon-treated cellulose. The synthetic media contributes to 95 percent emulsified water separation based on SAE 1488 testing procedures, according to Donaldson.
In addition to refining the media inside fuel filters, manufacturers are using new materials and techniques to make it easier to maintain the filters. Donaldson has introduced a patented Twist & Drain device to make it easier to drain water. The self-venting device requires only a half twist to open and provides an audible and tactile click when the drain is fully open. Donaldson also has an electronic sensor that can be placed in its P55 1003 filter. When the water reaches the sensor, a light in the cab indicates the device should be drained.
Engineered Products plans to introduce an electronic sensor for fuel filters this year. Filter Minders, a series of in-line visual indicators, measures how much restriction the filter is experiencing. The devices include clear plastic chambers and debris indicators to show how much useful life remains in the filter. "Filters tend to plug rapidly at the end of their life," says Ron Kelderman of Engineered Products. "They will run for long periods of time with no restriction and then at three-fourths of their useful life, they will clog up rapidly."
Fleetguard has also introduced an in-line fuel filter monitor. The Fuel Pro 180 line provides a similar visual indication of debris capture. "We will sell less filters because people will not be changing them unnecessarily," says Fleetguard's Burnette. "They will see when the debris has built up and will know exactly when to change it."
Clear plastic collection bowls are becoming more common on filtration systems. Parker Hannifin's Racor Division has a clear collection bowl as part of its 777R Series fuel filtration/water separator system that removes contaminants from fuel in two stages. In the first stage, fuel moves through a centrifuge that sends large solids and water droplets, which are heavier than fuel, to an outer surface. The water can drop to the bottom of the clear collection bowl, where an optional in-bowl water detection probe can activate a dashboard warning light. In the second stage, proprietary Aquabloc II cartridge elements repel water and remove fine contaminants from fuel.
The 777R includes a fuel primer port, an internal thermostat, and other optional features, such as a vacuum gauge kit and fuel heater, for even greater control and monitoring of fuel.
Easier draining technology, refined media, and improved monitoring have brought fuel filters into the future Steve Burnette was envisioning. Although fuel-filtration systems must continue to perform their basic function of helping deliver clean fuel, today's filters also help fleet managers more closely monitor their performance and efficiency.