When talking to end users about their filter choices, we often hear, “I have used XXX brand filter for years and never had any issues.” And, if we’re talking about older fuel systems, it’s actually not a surprising response, because those systems were inherently more tolerant of contamination. As demands for lower emissions, improved performance, and reduced fuel consumption have intensified, fuel injection system designs have changed. The most prominent design trend is a steady increase in maximum injection pressure in newer diesel engines. (Jääskeläinen, 2015). Where just 10 years ago injection pressures were in the sub 10,000 PSI (70 MPa) range; today they are exceeding 30,000 PSI (200 MPa).
Tier 4 fuel systems require better filtration
So the question is, how do increased injection pressures ultimately affect you and your equipment from a filtration perspective? The short answer—Tier 4 fuel systems are highly sensitive to contamination and thus require superior filtration. As injector pressures increase, maximum injector life is accomplished by limiting the size and number of particles that get through the fuel filter. All fuel filters remove some abrasive particles but many competitive filters are simply not effective at capturing and retaining the particles that are most damaging to fuel system components. In “engineer-speak”, fuel systems require filtration capable of removing particles in the sub-four micron range.
To put this into perspective, imagine your hand full of sand. You take that sand and throw it against a painted surface, say a car door. Not much happens right? Perhaps some minute scratches, but nothing overly noticeable. Now if you take that same handful of sand and apply added pressure from an air compressor, it will quickly and effortlessly remove the paint from that car door. In some scenarios it can actually create holes in the metal surface. This scenario is what takes place inside a fuel system when contaminates interact with the internal components at high pressure. They quickly erode away at various mating surfaces that ultimately have a negative impact on equipment performance and fuel economy.
Caterpillar puts high-efficiency fuel filters to the test
Caterpillar has completed testing on injector life in a Cat C9 engine fuel system. The test rig consisted of a factory cylinder head, fuel injectors, fuel pump, lines, and electronics. Highly contaminated fuel was circulated through the system at rated and high idle to simulate an extremely harsh operating environment. The test was terminated if the injector exhibited a leakage rate 3X that of new or achieved 50 hours in duration. The Cat 1R-0749 Advanced High Efficiency Fuel Filter was pitted against four similar competitive filter brands to compare injector life. Two filters for each brand were tested and the results averaged together to show the performance for each brand. The injectors with Cat filtration lasted 45% longer than the nearest competitor.
How can inadequate filtration affect your bottom line?
It’s challenging to determine the “true cost” of inadequate filtration because rarely can you draw a direct cause and effect line from a catastrophic failure to your choice of filters. However, if you monitor early hour failures across components in the system you can begin to calculate a bottom line cost. As part of Caterpillar’s injector study, we monitored early-hour failures across the life of the injectors when using different brands of filters.
When comparing the five top brands of fuel filters, you could realize a cost savings at the filter purchase ranging from 33 to 44% (on a $20 filter, that’s approximately $6.60 - $8.80 USD). And while you may start out ahead by a few dollars, the test data clearly shows you will quickly experience the effects of premature, early-hour injector failures. This could end up costing you thousands of dollars. Why take the risk?
How do you know if you have a fuel filtration problem?
To answer this question, we have to ask another one – what do you mean by filtration problem? A common complaint we hear from users is that Cat Filters “clog up too fast!” So they switch to another brand of filter and the filter no longer clogs. Let’s think about that: If the Cat filter is plugging and the non-Cat filter is not, what does that tell you? It tells you the problem is that the non-Cat filter is NOT capturing and holding contaminates and allowing them to pass freely through the fuel system. That is a real fuel filtration problem.
So, how do you know when a filter is clogged? Most newer machines will provide a fault code that basically is an indicator that differential pressure (Delta P) has increased to the point that the bypass valve is open. Once this occurs the filter should be changed out immediately. If you don’t, the machine will eventually de-rate to a low power state leading to decreased productivity and eventual downtime.
The trend for higher injection pressures is likely to continue. You’ll get the maximum return in performance and fuel system wear life by investing a few extra dollars in quality filters.
For more information about Cat’s studies on injector life, go to ChooseCatFilters.com.