Fuel system contamination can cause serious problems in any diesel engine. But today’s high-performance, low-emissions models – with their high injection pressures and extremely tight tolerances – are especially vulnerable to contaminants. Microscopic particles suspended in your fuel can be particularly damaging to injectors and control valves. As these critical components wear prematurely, engine power drops off, fuel consumption rises, emissions increase and the odds of a costly breakdown go up dramatically. It’s obviously in your best interests to control fuel system contamination. Here are eight things you can do to clean up your act:
Know the numbers
Contaminants are measured in units called microns. One micron is equivalent to one-millionth of a meter. A grain of salt is about 100 microns in diameter, a human hair, around 80. We can’t see particles smaller than 40 microns, yet a 5-micron particle can damage your fuel system. Most fuel filters are designed to trap particles ranging in size from 4 to 15 microns. For maximum protection, select a filter that’s effective against an absolute rating of 4-micron and larger particles.
Beware of ambiguous micronratings
Some filter manufacturers give their products“nominal” and “absolute” micron ratings. These ratings are normally based on a laboratory analysis called the multipass test. In multipass testing, a concentrated stream of artificial contaminants is added to an oil sample that flows through a testing unit at a constant rate. The oil moves through a filter, which is progressively loaded until a specified pressure drop is reached. During the test, particles entering and exiting the filter are sized and counted.
Then two metrics – called “beta ratios” – are calculated. The first beta ratio compares the number of particles 5 microns and larger upstream of the filter, versus the number downstream. The second compares particles 15 microns and larger. Some manufacturers use these ratios to define their products’ so-called nominal and absolute ratings. The truth is, ratings based on multi pass test data aren’t very meaningful. That’s because the test, though useful for product development, is not an ideal performance evaluation tool. It uses oil instead of fuel. It doesn’t simulate real-world conditions such as vibration and fuel pump pulsation. And it reports average filter efficiency, downplaying the impact that even a few contaminants can have on fuel system components. Given the limitations of multipass testing, it’s a mistake to place too much emphasis on micron ratings. In fact, the term “micron rating” has no official standing within the major industry technical groups like the Society of Automotive Engineers (SAE) or the National Fluid Power Association (NFPA). So when comparing filters, don’t be misled by the rating system. Focus instead on product features, structural integrity and consistency of quality.
Find out about the wear index
A better filter testing process called wear indexing was developed several years ago by an independent testing company at the request of a filter industry consortium. Wear indexing uses low sulfur fuel as a test fluid. It also incorporates vibration and pulsation into the analysis, so it provides results that are more meaningful and credible than those obtained throughmultipass testing. A filter’s wear index is based on a correlation between the amount of physical damage observed on the injectors and the number of 6-, 10- and 14-micron particles present in the fuel. A filter with a higher wear index provides less protection than one with a lower number. Independent researchers have tested a variety of filtration products to measure their wear indices.Results vary widely from a low of .04 to a high of more than 80. Ask your supplier if the filters you are using have been wear-index tested. Then determine if a lower-wear-index product is available to extend injector life, improve fuel economy and reduced emissions.
Manage fuel storage and transfer
Without proper storage and handling procedures, even the cleanest fuel can become contaminated. To keep sediment, dirt and other contaminants out of your fuel supply, periodically drain and flush all storage containers, including tanker trucks and stationary tanks. Make sure storage and machine fuel tanks are properly vented with breathers that keep 4-micron and larger particles out. Keep all fuel nozzles, hoses and other equipment clean. Maintain the hoses, gaskets and seals in your fuel storage and transfer equipment. Use line filters on all fuel transfer equipment, and never transfer fuel with buckets, funnels or other open containers. Bottom line: the way you store and handle fuel has a major impact on its cleanliness. Be sure your procedures are attacking not generating contaminants.
Involve operators
Operators play a key role in reducing fuel system contamination. At the start of each shift, they should perform a quick visual inspection. Any leaky lines should be repaired immediately. The fuel cap should be checked to ensure it’s properly installed and sealing effectively. If the gasket around the cap is damaged, it should be replaced immediately. Prior to machine start-up, it’s also important to confirm that fuel tank vent tubes are open and functioning correctly. During operation, a machine should never be run to the point where the fuel tank is completely empty. Doing so can draw sediment from the bottom of the tank into the fuel system. If the operator experiences hard starting (especially when warm), excessive smoke or any unexplained loss of power, maintenance or servicetechnicians should be notified immediately. Fighting contamination is everyone’s responsibility. Be sure your operators understand the critical role they play in improving fuel system cleanliness.
Train technicians
Contaminants often invade an engine while it’s being serviced. To minimize service-related contamination, technicians should be taught to use proper maintenance and repair processes. During filter changes, remove filters carefully so dirt and debris from the engine compartment doesn’t get into any openings. Keep new filters in their original packaging until they’re installed. And don’t pre-fill them prior to installation. Doing so allows some fuel to bypass the filter altogether. For other types of engine service, use a high-pressure wash to blast mud, dust and other grime off the engine before opening it for repairs. Cap or plug all openings. Clean reusable parts with solvents and proper cleaning and drying processes. Never place components on the ground,and keep all new parts in their packages until needed. Don’t reuse seals – replace them. Be sure to inspect fuel line connections from the tank to the pump. And maintain a regular schedule for draining machine fuel tanks – weekly or severely dusty conditions and every three months for normal applications.
Contaminated fuel robs your engine of power. It reduces fuel efficiency, Mine Property Exchange Where Mining Properties are Bought and Sold! www: PropertyExchange.InfoMine.com Conveniently browse our database of hundreds of available properties from around the globe by country, commodity and deposit type. Expose your mineral property to the largest online mining community through InfoMine’s Property Exchange. http://propertyexchange.infomine.com + 1 604 683 2037 increases emissions, shortens component life and paves the way for engine failure. You can minimize the effects of dirty fuel by choosing high-quality filtration products and using proper storage, handling, maintenance and service processes. It pays to fight back against contamination. So clean up your act, and bring home the benefits: better performance, longer life, lower operating costs and a higher return on your engine investment.
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