23937116 diesel fuel filters

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Diesel Filter

A diesel particulate filter, sometimes called a DPF, is a device designed to remove

diesel particulate matter or soot from the exhaust gas of a diesel engine. A diesel-powered vehicle equipped with a functioning filter will emit no visible smoke from itsexhaust pipe. Wall-flow diesel particulate filters usually remove 85% or more of thesoot, and can at times (heavily loaded condition) attain soot removal efficiencies of

close to 100%.

3 Already in recent years several numerical models have been developed tosimulateglobally the soot loading capacity, the pressure drop evolution and the

regenerationbehaviour in typical ceramic wall-flow filters [13, 19]. Less effort hasbeen devoted tothe development of dedicated models for the simulation of themicrostructuralthermo-mechanical behaviour of the ceramic filter at high temperature, to evaluatetheresistance to thermal fatigue (crack formation and evolution), corrosion(ashescontact), substrates oxidation and filtration efficiency evolution (porosity andmicro-cracks modifications).Furthermoremacrostructural

properties of the filter and the mat in order to optimisethe canning process and in

service durability should be predicted by computermodelling. Among the mat failuresto be foreseen, the vermiculite collapse at hightemperature, the incomplete binder

burning and the fibre erosion due to strongvibrations are the most important ones.Sofar no modelling software in the Automotive industry is available, where the micro-structural evolution of filter material and the macroscopic behaviour of thecompleteengine exhaust system due to soot deposition/burn off and temperatureinducedstresses can be computed, let alone mesh generators of typical porous filtermaterial.Multiscale simulationsThe need for engineering modelling tools to assist DPF and overall exhaustsystemdesign optimization already in the past has let to different approaches on the

basis of1D and 3D [11] models. However, all of them are applied solely onamacroscopic level, where homogeneous porosities and measured permeabilitiesareused to model the effect of filter material on the exhaust gas flow. Withoutextensiveexperimental calibration the predictive capability of these models proved to

belimited.Only a few attempts [10, 16] are known to compute micro-structural flowphenomenain filters using the Lattice-Boltzmann-Method (LBM). The work therebyfocussed onthe computation of cold flow and particle deposition in porous media andnot on heattransfer and chemical surface reactions due to inherent limitations of the

LBM in thisarea.Recently also the explicit coupling of 1D and 3D software [20] withrespect to filterregeneration modelling was attempted. The approach showed certain


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problems. Inparticular the initial filter temperature and accumulated soot distributionat the onsetof the regeneration process (at the so called

balance point), which has a significanteffect on the subsequent temperature evolution in the filter,

could not be takenphysically plausible into account.In what follows, the basic tools toanalyse on a purely theoretical basis physical andchemical phenomena in DPFs arepresented.

OpenFOAMOpenFOAM is a C++ library, used primarily to create executables, knownasapplications. The applications fall into two categories: solvers, that are eachdesignedto solve a specific problem in continuum mechanics; and utilities, that aredesigned toperform tasks that involve data manipulation. The OpenFOAMdistribution containsnumerous solvers and utilities covering a wide range of problems

[18].One of the strengths of OpenFOAM is that new solvers and utilities can becreatedby its users with some pre-requisite knowledge of the underlying method,

physicsand programming techniques involved [17].For all the above reasons,OpenFOAM is the perfect basis for a multiscale,multiphysics software tool that can

be used for exhaust gas aftertreatmentdevelopment.DexaSIMIn the past extensive research and software development on Diesel exhaustsystemmodelling has already been performed The result is the software calledDieselEXhaust gas Aftertreatment SIMulation, in short: DexaSIM DexaSIM in its

current experimentally validated development statuspermits the simulation of filterloading due to soot deposition on a microscopicmaterial level and globally in theexhaust system. In the latter case also heatconduction processes in the solid filtermaterial can be taken into account.Additionally chemical reaction schemes to modelfilter regeneration on a microscopicand macroscopic level are already integrated. Anoverview of DexaSIM and all itsmultiscale, multiphysics [14, 29] modules is shownin Figure 1. Highlighted are themodules that are important for the multiscaleapproach.Figure 1 General structure of DexaSIM, highlighted are the multiscale modules


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5 Computational Fluid Dynamics (CFD) in the microstructures based on theOpenSource software OpenFoam [31] is used to bridge the gap between thematerialsmicroscopic structure and the macroscopic properties needed in the globalanalysisof the complete exhaust system.The microstructural CFD moduleMicroFOAM computes the permeability of clean andsoot loaded filter materialsamples. The global permeability data as a function of sootloading are stored in adatabase and can be subsequently accessed by the moduleMacroFOAM, whichenables the analysis of the complete exhaust systems. In bothsoftware modulesmodelling of soot particle flow and deposition is based on theMethod-of-Moments

[28].By using this approach of combining the flexibility of OpenFOAM and the GUIofDexaSIM, multiscale simulation methods are embedded in one single

programsystem, whereby the visualisation of all computed results is done via theOpenSource Post-Processing software ParaView [32].Modelling on a microscopic scaleThe microstructural geometry generator contained within DexaSIM permitsthereconstruction of material samples from 2D Computer Tomography (CT) dataandfrom 2D Scanning Electron Microscopy (SEM) data. By using statisticalfunctions(e.g. pore diameter distribution, pore distance autocorrelations, lineal path

functions,etc.) material samples are mathematically characterised. These data arestored in adatabase (see Figure 1) and can be retrieved to change or modify viavariation ofmathematical parameters a certain material sample and to design newmaterials withimproved performance. Additionally via clustering/filtering of CT greyscale images,deposited soot or accumulated ashes can be detected [4].Isotropic material reconstruction methodThe reconstruction of an isotropic digitised model (mesh) of any porous structurecanbe summarised by the following steps:1. obtaining a 2D digital image of thematerial2. retrieving statistic parameters of the image using DexaSIM [2, 6, 22, 26,33]3. reconstruct 3D digital model or mesh according to statistical parameters [1,

8]An example of the reconstruction of a foam structure from a 2D CT image canbeseen in Figure 2.The previous described algorithm creates a 3D computational


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model out of a 2Dimage. This always returns an isotropic computational model withthe same statisticalcharacteristics in all main directions

Diesel engines are relatively simple devices. They only require three things: clean air,clean oil and clean fuel. On a boat, clean air is easy, just keep the air filter clean andyou're good. Clean oil is slightly more difficult, but as long as you follow the

manufacturers' suggested oil change schedule, it too can be had.

It is the need for clean fuel where things start to get dicey.

Depending on the source of the fuel and your storage arrangements, diesel fuel can beinfiltrated by water, particulates and various chemical contaminates. Water, in

particular, can be very damaging to the precision fuel management components in adiesel engine. Under the typical pressures used in diesel fuel pumps and injectors,water can actually act as an abrasive, quickly wearing down components.

And so, every engine has a filtration system to combat contamination. Note that I said"system," because proper and effective fuel filtration should include two types of fuelfilters: a primary filter and a secondary filter.


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RACORThe Racor 120 is a widely used spin-on element fuel filter.Installing a dieselfuel filter is easily done by the average boater. But you must take your time and doyour homework. This is, after all, your fuel systeman organ your engine cannot runwithout. Do it right, however, and your engine will be easier to service and run more

reliably.

FILTER BASICS

Most diesel engines come equipped with a secondary filter as part of the engine-mounted fuel delivery system. This on-engine filter is most often rated at two microns(see graphic). This is sufficient to remove hard particles that can damage precisionfuel delivery components.

However, a secondary filter typically does not usually remove water from the fuel.

That job is handled by a primary filter, which is usually added by the boat builder orengine installer between the tanks and the engine.

If your boat lacks a basic two-filter system, you can install new filters easilyandyou should. Single-filter systems are much more prone to clog and lose effectiveness.

Diesel fuel filters can be divided roughly into two groups" spin-on or drop-in. Spin-on fuel filters utilize a paper element to strain fuel, which is then encased in a metalliccase, similar to an oil filter. These filters screw onto a bracket and have a separate

bottom bowl that screws onto the filter unit. This style of filter is usually relegated to

lower capacity applications (capacity is rated in Gallons Per Hour, or GPH).

One popular diesel filter is the Racor model 120RMAM. This filter is available withspin-on elements of either two microns or 30 microns (the 30 micron is used for

primary filtration). This unit is rated at 15 GPH. It has a metal bowl and requires only2-inches of service clearance underneath the unit for removing the spin-on filterelement. It has two inlet and two outlet ports, to accommodate multiple tanks andengines, or inlets and outlets can be plugged for use in a single-engine or single-tankinstallations. The filter is less than 6-inches high and 4-inches wide, allowing a

compact installation.

Drop-in element filters have a housing that can be opened up to receive a separatedrop-in element. These filters usually accommodate higher capacity than spin-onfilters. One example of a widely-used drop-in element filter is the Racor 500FG. Thisfilter is rated at 60 GPH with a 10 micron element. This filter is much larger than thespin-on type, at 11.5-inches high and 5.8-inches wide. The inlet and outlet ports arealso larger, at -16 UNF. You will also need more room under the filter unit formaintenance, 4 inches in this case. This unit is also available in a dual filter setup, the75/500FGX.


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SYSTEM CONFIGURATIONS

Most primary filters are installed on the vacuum side of the fuel pump. Vacuumgauges are also sometimes installed to gauge the health of the primary filter. Whenthe vacuum gauge rises to a given level, it is time to change filters.

A filter change can result in some additional problems when air is induced into thelines, requiring the dreaded "bleed" of the fuel system. To avoid this, new filtersshould be filled with clean diesel before being installed. In fact, many drop-in elementfilters have ports on the top of the filter to pre-fill the assembly. This helps reduce thechances of getting air into the fuel systemand the need to bleed.

You can also minimize the chance of getting air in your fuel lines and make filtermaintenance much easier by installing dual filters and plumbing that allows you toisolate each filter. In this arrangement, a two-way valve allows you to switch from theclogged filter to a new filter. The clogged filter then can be changed out while theengine is still running.

Many filter manufacturers, including Racor, offer these units pre-plumbed, thoughthey can be expensive. Typically, the two filters are mounted side-by-side on a metal

mounting bracket, with the filter selector valve between the two. Another option is tocreate the system yourself, creating a plumbing scheme with a bypass feature that willallow you to switch the filter out of the fuel line. It requires three on-off fuel valvesand some extra plumbing, but the price is much more reasonable than a preassembledcommercial unit.

The system has an on-off fuel valve before and after the filter unit. A bypass fuel linewith another on-off valve is installed before the first valve and after the second valve(see graphic). By closing the valves before and after the filter and opening the valve inthe bypass line, the fuel will flow around and the filter. After changing out the filterelement, you open the two valves in the main line and close the bypass valve, putting


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the filter back on line. If the stars are aligned and your luck holds, bleeding the enginewon't be necessary. You take a slight chance running on bad fuel while the filter ischanged, but the secondary filter should still protect the engineand the cost savingsis substantial.

RACORThe Racor 500 seriesis a popular drop-in fuel filter.In addition to the vacuum gauges, several other filteroptions are available. Water probes can be installed in some filters, as can manual fuel

pumps to make bleeding the filter and engine easier. Some diesel fuel filters are

available with an optional see-through bowl on the bottom. This makes it easy toinspect the quality of the fuel and drain off any water using the fuel drain on the

bottom of the bowl. However, a little-known ABYC (American Boat and YachtCouncil) standard requires any fuel filter installed in an engine space have a firerating. This requires a metallic bowl or bowl protector.

A standard option in Racor filter elements is something called Aquabloc. This is achemical treatment for the element paper that keeps water from passing through thefilter. This water then drops down to the filter bowl where it can be drained. The onecaveat with this treatment is that the effective life for the treatment is one year, afterwhich its effectiveness falls off.

INSTALLATION CONSIDERATIONS

Once you have decided on the rating of your primary filter (10, 20 or 30 microns),your next decision is the size of the filter in GPH. Most engine manuals will provide afuel consumption curve or maximum fuel consumption figure. If not, you can roughlyestimate the fuel consumption of your engine by using the formula:

Gallons Per Hour = Horsepower (max) x 0.18


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In other words, maximum fuel consumption in GPH is 18 percent of the maximumhorsepower rating.

Proper sizing is important because many diesels pump much more fuel than isactually consumed. That additional fuel is used to cool parts of the fuel system and toinsure sufficient fuel is present for throttle increases without any lag. The excess fuelis then returned to the tank.

Unless properly rated, filters should be installed outside of the engine or generatorspace. Size-up the hose requirements before starting any installation. Check therouting of each hose to avoid any hot spots or areas where the hose may rub or chafe.Plan on supporting the hose every 18 inches or so to avoid any unnecessary flexing orrubbing. Resist the temptation to increase the size of the fuel line; a larger fuel linemeans an increase in the weight of the fuel to be pumped and may overtax the fuel

pump.

Pay particular attention to the size and style of the hose connections. Most filterscome with female NPT ports into which you can screw different fittings. Never useTeflon plumbers tape when installing these fittings. Use a thread sealant instead.

RACORThis is an example of

a pre-packaged dual filter unit.In some cases, standard barbed fittings and hoseclamps are used. In many larger installations, specialized hose ends and fittings arerequired. In all installations, do not assume that fittings are compatible. For example,JIC fittings are machined with a 37-degree bevel on the sealing end. SAE fittings, onthe other hand, have a 45-degree bevel, so the two are definitely not interchangeable.If you don't know exactly what type of fitting is used, take a sample hose to a localchandlery or diesel shop and have them identify it.

If your installation will require hoses be made up at an outside shop, spend the time toproperlyand definitivelydetermine the hose path and lengths. Having to leave theboat to have a hose re-made will be more time consuming than measuring twice.


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ROOM TO WORK

It sounds elemental, but make sure there is enough clearance and access to properlyservice the filter. There should be plenty of room above the filter if you are using adrop-in filter, and room below to place an appropriate sized container to control anydrips or spills.

Your filters will also need an adequate surface for mounting. A filter full of fuelrepresents a considerable amount of weight, and that can stress weak bulkheads. Usethru-bolts and locking nuts for security.

One of the most critical steps in installing a filter is eliminating leaks. On the suctionside, air will leak into the fuel system, making successful bleeding problematic. Thisis why plumbers putty or thread compound, such as Permatex Pipe Joint Compound,

is used, rather than Teflon plumbing tape.

While the suction side of the system is the usual location for a primary filterinstallation, you can also install a filter on the pressure side of the pump. But themaximum allowable pressure and fuel flow ratings for the filter must be well abovethe fuel pump pressure and flow. The downside of this location is that the pressure,coupled with the need for more connections, can result in an increased chance of fuelleaks. While on the suction side, air will leak into the system, on the pressure side,fuel will leak out of the systemand under pressure at that.

No matter where you locate your filters, make sure you change them regularly. Checkthe filters evey time you check engine fluids. By monitoring the pressure gauges (forsystems on the vacuum side), you can see when filters need changing. Carry severalspares and change at the first sign of trouble, making sure to fill the unit with fuel toeliminate the need to bleed. Your engine will thank you

Bibliography[1] Bach, G.,ber die Bestimmung von charakteristischen Gren einer Kugelverteilung aus der

Verteilung der Schnittkreise, Zeitschrift frwissenschaftliche Mikroskopie65,1963, pp. 285-291[2] Borgefors, G., Nystrm, I.,Efficient shape representation by minimizing the set of centres of maximaldiscs/spheres, Pattern Recognition Letters, Vol.18,1996, pp. 465-472[3] Brandsttter, W., Wassermayr, C., Prenninger, P.,An Integrated Approach for the Design of Diesel Engine Exhaust Systems to meetEuro 4 and beyond Emissions Legislations


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, THIESEL 2002/Thermodynamic Processes in DieselEngines, 11.-13. September2002, Valencia[4] Brandsttter, W., Leixnering, J., Faraldi, P., Merlone Borla, E.,Ranalli, M.,Vlachos, N., Konstandopoulos, A.G.,The STYFF-DEXA Project: Advanced Simulation Tools for Ceramic Foam Diesel

Particulate Filters, ICE2005 - 7thInternational Conference on Engines for Automobile 11/09/2005 -16/09/2005[5] Brandsttter, W., Leixnering, J., Faraldi, P., Ranalli, M. and Vlachos,

N.,The STYFF-DEXA Project: Advanced Simulation Tools for Ceramic FoamDiesel Particulate Filters[6] Breu, H., Gil, J., Kirkpatrick, D., and Werman, M.,Linear Time Euclidean Distance Transform Algorithms, IEEE Transactions on Pattern Analysis andMachine Intelligence, Vol.17

, No. 5,1995, pp. 529-533[7] DexaSIM User manual, DexaSIM 0.9, ICEStrmungsforschung GmbH, 2007[8] Goldsmith, P.L., The calculation of true particlesize distribution from the sizesobserved in a thin slice, Brit. J. Appl. Phys.18, 1967, pp. 813-830[9] Gschaider, B.F.W., Honeger, C.C., Redl, C.E.P,Soot Particle Deposition within Porous Structures Using a Method of MomentsLattice Boltzmann Approach, Computational Science ICCS 2004, 4th International ConferenceKrakw Poland,June 6-9, 2004[10] Gschaider, B.F.W., Honeger, C.C., Redl, C.E.P.,

Soot Particle Deposition within Porous Structures Using a Method of Moments, Lattice Boltzmann

19Approach, Computational Science ICCS 2004 4th InternationalConferenceKrakw Poland, June 6-9, 2004[11] Janoske, U., Deuschle, T., Piesche,M.,Modelling of Filtration and Regeneration Processes in Diesel Particulate Traps, Mathematics in Industry,Vol.8Progress in Industrial Mathematics at ECMI 2004, part III, pp 252-256Springer BerlinHeidelberg, 2006[12] Konstandopoulos et al.,The Diesel Exhaust Aftertreatment (DEXA) Cluster: ASystematic Approach to DieselParticulate Emission Control in Europe, A.G.,SAE 2004-01-0694

23937116 diesel fuel filters

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