What Is A Particulate Filter

Removes diesel particulate thing or soot from the exhaust gas of a diesel engine

A diesel particulate filter (top left) in a Peugeot

Off-road - DPF installation

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.^{[1] [2]}

Mode of action [edit]

Wall-menses diesel fuel particulate filters commonly remove 85% or more of the soot, and under certain conditions tin can attain soot removal efficiencies budgeted 100%. Some filters are single-use, intended for disposal and replacement in one case full of accumulated ash. Others are designed to burn off the accumulated particulate either passively through the apply of a catalyst or past active ways such as a fuel burner which heats the filter to soot combustion temperatures. This is achieved by engine programming to run (when the filter is full) in a manner that elevates exhaust temperature, in conjunction with an extra fuel injector in the exhaust stream that injects fuel to react with a catalyst element to burn off accumulated soot in the DPF filter,^[3] or through other methods. This is known equally filter regeneration. Cleaning is also required as function of periodic maintenance, and it must be done carefully to avoid damaging the filter. Failure of fuel injectors or turbochargers resulting in contamination of the filter with raw diesel or engine oil can also necessitate cleaning.^[4] The regeneration process occurs at route speeds higher than can generally be attained on city streets; vehicles driven exclusively at depression speeds in urban traffic tin crave periodic trips at higher speeds to clean out the DPF.^[five] If the driver ignores the warning calorie-free and waits besides long to operate the vehicle above sixty km/h (40 mph), the DPF may non regenerate properly, and continued performance past that point may spoil the DPF completely so it must exist replaced.^[6] Some newer diesel engines, namely those installed in combination vehicles, can also perform what is chosen a Parked Regeneration, where the engine increases RPM to around 1400 while parked, to increase the temperature of the exhaust.

Diesel engines produce a variety of particles during combustion of the fuel/air mix due to incomplete combustion. The composition of the particles varies widely dependent upon engine type, age, and the emissions specification that the engine was designed to run across. Two-stroke diesel engines produce more particulate per unit of ability than do four-stroke diesel engines, as they burn the fuel-air mix less completely.^[seven]

Diesel particulate matter resulting from the incomplete combustion of diesel fuel produces soot (black carbon) particles. These particles include tiny nanoparticles—smaller than one micrometre (one micron). Soot and other particles from diesel engines worsen the particulate thing pollution in the air and are harmful to health.^[eight]

New particulate filters tin capture from 30% to greater than 95% of the harmful soot.^[9] With an optimal diesel particulate filter (DPF), soot emissions may be decreased to 0.001 one thousand/km or less.^[10]

The quality of the fuel also influences the formation of these particles. For case, a loftier sulphur content diesel produces more particles. Lower sulphur fuel produces fewer particles, and allows use of particulate filters. The injection pressure of diesel fuel besides influences the formation of fine particles.

History [edit]

Diesel particulate filtering was showtime considered in the 1970s due to concerns regarding the impacts of inhaled particulates.^[11] Particulate filters accept been in employ on non-road machines since 1980, and in automobiles since 1985.^{[12] [thirteen]} Historically medium and heavy duty diesel engine emissions were not regulated until 1987 when the first California Heavy Truck dominion was introduced capping particulate emissions at 0.60 one thousand/BHP Hour.^[14] Since so, progressively tighter standards have been introduced for low-cal- and heavy-duty roadgoing diesel-powered vehicles and for off-road diesel engines. Similar regulations take also been adopted by the European Matrimony and some individual European countries, most Asian countries, and the balance of North and South America.^[fifteen]

While no jurisdiction has explicitly fabricated filters mandatory, the increasingly stringent emissions regulations that engine articles must meet mean that eventually all on-road diesel fuel engines will be fitted with them.^[14] In the European Spousal relationship, filters are expected to be necessary to see the Euro.Half dozen heavy truck engine emissions regulations currently nether discussion and planned for the 2012-2013 fourth dimension frame. In 2000, in anticipation of the time to come Euro 5 regulations PSA Peugeot Citroën became the first company to make filters standard on rider cars.^[xvi]

As of Dec 2008 the California Air Resource Board (CARB) established the 2008 California Statewide Truck and Bus Dominion which—with variance according to vehicle type, size and usage—requires that on-route diesel heavy trucks and buses in California be retrofitted, repowered, or replaced to reduce particulate matter (PM) emissions by at least 85%. Retrofitting the engines with CARB-approved diesel fuel particulate filters is i manner to fulfill this requirement.^[17] In 2009 the American Recovery and Reinvestment Human action provided funding to aid owners in offsetting the cost of diesel retrofits for their vehicles.^[18] Other jurisdictions have also launched retrofit programs, including:

• 2001 - Hong Kong retrofit programme.^[19]
• 2002 - In Japan the Prefecture of Tokyo passed a law banning trucks without filters from entering the metropolis limits.^[20]
• 2003 - United mexican states City started a plan to retrofit trucks.^[21]
• 2004 - New York City retrofit program (non-route).^[22]
• 2008 - Milan Ecopass surface area traffic accuse – a hefty entrance tax on all diesel vehicles except those with a particulate filter, either stock or retrofit.^[23]
• 2008 - London low emission zone charges vehicles that do not meet emission standards, encouraging retrofit filters.^{[24] [25]}

Inadequately maintained particulate filters on vehicles with diesel engines are prone to soot buildup, which tin can cause engine problems due to high back pressure.^[4]

In 2018 the UK made changes to its MOT test requirements,^[26] including tougher scrutiny of diesel cars. Ane requirement was to have a properly fitted and working DPF. Driving without a DPF could incur a £grand fine.^{[27] [28]}

Variants of DPFs [edit]

Cordierite Diesel Particulate Filter on GM 7.8 Isuzu

Unlike a catalytic converter which is a flow-through device, a DPF retains bigger exhaust gas particles by forcing the gas to menstruation through the filter;^{[two] [29]} however, the DPF does non retain minor particles. Maintenance-free DPFs oxidise or burn larger particles until they are pocket-size enough to pass through the filter, though ofttimes particles "clump" together in the DPF reducing the overall particle count as well as overall mass.^{[30] [31]} There are a variety of diesel particulate filter technologies on the market place. Each is designed effectually like requirements:

1. Fine filtration
2. Minimum force per unit area drib
3. Low price
4. Mass product suitability
5. Production durability

Cordierite wall menstruation filters [edit]

The most mutual filter is made of cordierite (a ceramic fabric that is also used as catalytic converter supports (cores)). Cordierite filters provide excellent filtration efficiency, are relatively inexpensive, and accept thermal properties that make packaging them for installation in the vehicle unproblematic. The major drawback is that cordierite has a relatively low melting point (near 1200 °C) and cordierite substrates have been known to melt during filter regeneration. This is mostly an effect if the filter has become loaded more heavily than usual, and is more than of an issue with passive systems than with active systems, unless there is a organisation breakdown.^{[2] [32]}

Cordierite filter cores look similar catalytic converter cores that have had alternating channels plugged - the plugs force the exhaust gas menstruum through the wall and the particulate collects on the inlet face.^[33]

Silicon carbide wall flow filters [edit]

The second most pop filter textile is silicon carbide, or SiC. Information technology has a college (2700 °C) melting point than cordierite, however, information technology is not as stable thermally, making packaging an issue. Pocket-sized SiC cores are fabricated of single pieces, while larger cores are fabricated in segments, which are separated by a special cement and so that heat expansion of the cadre volition be taken up by the cement, and not the package. SiC cores are unremarkably more expensive than cordierite cores, however they are manufactured in like sizes, and one tin often be used to supplant the other. Silicon carbide filter cores also expect like catalytic converter cores that have had alternate channels plugged - again the plugs force the frazzle gas menstruation through the wall and the particulate collects on the inlet face.^{[two] [34]}

The characteristics of the wall flow diesel fuel particulate filter substrate are:

• broad ring filtration (the diameters of the filtered particles are 0.2–150 μm)
• loftier filtration efficiency (can be up to 95%)
• loftier refractory
• loftier mechanical properties
• high boiling point.^[34]

Ceramic fiber filters [edit]

Fibrous ceramic filters are made from several different types of ceramic fibers that are mixed together to grade a porous medium. This medium can be formed into almost any shape and can exist customized to accommodate various applications. The porosity tin can be controlled in order to produce high menstruation, lower efficiency or high efficiency lower volume filtration. Fibrous filters have an advantage over wall flow pattern of producing lower dorsum pressure. Gristly ceramic filters remove carbon particulates most completely, including fine particulates less than 100 nanometres (nm) diameter with an efficiency of greater than 95% in mass and greater than 99% in number of particles over a wide range of engine operating conditions. Since the continuous menstruum of soot into the filter would somewhen block it, it is necessary to 'regenerate' the filtration properties of the filter past burning off the collected particulate on a regular basis. Soot particulate burn-off forms water and CO₂ in modest quantities amounting to less than 0.05% of the CO_two emitted past the engine.^[2]

Metal cobweb flow-through filters [edit]

Some cores are fabricated from metal fibers – generally the fibers are "woven" into a monolith. Such cores have the advantage that an electric current can be passed through the monolith to heat the cadre for regeneration purposes, allowing the filter to regenerate at low exhaust temperatures and/or low exhaust flow rates. Metal fiber cores tend to be more than expensive than cordierite or silicon carbide cores, and are mostly non interchangeable with them because of the electrical requirement.^{[2] [35]}

Paper [edit]

Disposable paper cores are used in certain specialty applications, without a regeneration strategy. Coal mines are common users – the frazzle gas is ordinarily first passed through a h2o trap to absurd it, then through the filter.^[36] Paper filters are too used when a diesel machine must be used indoors for short periods of time, such as on a forklift being used to install equipment within a store.^{[two] [37]}

Partial filters [edit]

In that location are a variety of devices that produce over 50% particulate matter filtration, but less than 85%. Partial filters come in a multifariousness of materials. The only commonality between them is that they produce more back pressure than a catalytic converter, and less than a diesel particulate filter. Partial filter applied science is pop for retrofit.^[38]

Maintenance [edit]

Filters crave more maintenance than catalytic converters. Ash, a byproduct of oil consumption from normal engine operation, builds up in the filter equally it cannot be converted into a gas and laissez passer through the walls of the filter.^[39] This increases the pressure earlier the filter. Warnings are given to the driver earlier filter restriction causes an issue with driveability or damage to the engine or filter develop. Regular filter maintenance is a necessity.^[iv]

DPF filters get through a regeneration process which removes this soot and lowers the filter pressure. There are 3 types of regeneration: passive, active, and forced. Passive regeneration takes identify normally while driving, when engine load and vehicle drive-cycle create temperatures that are loftier enough to regenerate the soot buildup on the DPF walls. Active regeneration happens while the vehicle is in use, when low engine load and lower exhaust gas temperatures inhibit the naturally occurring passive regeneration. Sensors upstream and downstream of the DPF (or a differential pressure sensor) provide readings that initiate a metered addition of fuel into the exhaust stream. There are two methods to inject fuel, either downstream injection straight into the exhaust stream, downstream of the turbo, or fuel injection into the engine cylinders on the frazzle stroke. This fuel and exhaust gas mixture passes through the Diesel Oxidation Catalyst (DOC) creating temperatures high enough to burn off the accumulated soot. Once the force per unit area drop beyond the DPF lowers to a calculated value, the process ends, until the soot accumulation builds upwardly again. This works well for vehicles that drive longer distances with few stops compared to those that perform brusque trips with many starts and stops. If the filter develops too much pressure and then the last blazon of regeneration must be used - a forced regeneration. This can be accomplished in two ways. The vehicle operator can initiate the regeneration via a dashboard mounted switch. Various signal interlocks, such as park brake practical, transmission in neutral, engine coolant temperature, and an absence of engine related mistake codes are required (vary by OEM and application) for this process to initiate. When the soot accumulation reaches a level that is potentially damaging to the engine or the exhaust system, the solution involves a garage using a calculator programme to run a regeneration of the DPF manually.

Rubber [edit]

In 2011, Ford recalled 37,400 F-Serial trucks with diesel engines subsequently fuel and oil leaks caused fires in the diesel fuel particulate filters of the trucks. No injuries occurred before the recall, though 1 grass fire was started.^[40] A similar think was issued for 2005-2007 Jaguar S-Blazon and XJ diesels, where large amounts of soot became trapped in the DPF In afflicted vehicles, smoke and burn emanated from the vehicle underside, accompanied past flames from the rear of the exhaust. The rut from the fire could cause heating through the transmission tunnel to the interior, melting interior components and potentially causing interior fires.^[41]

Regeneration [edit]

Metering pump for Diesel fuel or additive injection, iii Fifty/h at 5 bar

Diagram of the regeneration

Regeneration is the process of burning off (oxidizing) the accumulated soot from the filter. This is washed either passively (from the engine'south exhaust rut in normal performance or by adding a goad to the filter) or actively introducing very high heat into the exhaust system. On-board active filter management can apply a multifariousness of strategies:^[9]

1. Engine management to increment exhaust temperature through tardily fuel injection or injection during the exhaust stroke
2. Use of a fuel-borne catalyst to reduce soot burn down-out temperature
3. A fuel burner after the turbo to increment the exhaust temperature
4. A catalytic oxidizer to increase the exhaust temperature, with after injection (HC-Doser)
5. Resistive heating coils to increase the exhaust temperature
6. Microwave energy to increase the particulate temperature

All on-board agile systems utilise extra fuel, whether through burning to heat the DPF, or providing extra power to the DPF'south electric system, although the employ of a fuel borne catalyst reduces the energy required very significantly. Typically a computer monitors one or more than sensors that measure back pressure level and/or temperature, and based on pre-programmed ready points the calculator makes decisions on when to activate the regeneration cycle. The additional fuel can be supplied by a metering pump. Running the cycle besides ofttimes while keeping the back pressure in the frazzle system depression will result in high fuel consumption. Not running the regeneration wheel soon enough increases the gamble of engine damage and/or uncontrolled regeneration (thermal delinquent) and possible DPF failure.

Diesel fuel particulate thing burns when temperatures above 600 °C are attained. This temperature tin be reduced to somewhere in the range of 350 to 450 °C past use of a fuel-borne catalyst. The actual temperature of soot fire-out will depend on the chemistry employed. The start of combustion causes a further increase in temperature. In some cases, in the absenteeism of a fuel-borne goad, the combustion of the particulate matter can raise temperatures above the structural integrity threshold of the filter cloth, which can cause catastrophic failure of the substrate. Diverse strategies accept been developed to limit this possibility. Notation that different a spark-ignited engine, which typically has less than 0.5% oxygen in the exhaust gas stream before the emission control device(south), diesel engines accept a very high ratio of oxygen bachelor. While the corporeality of bachelor oxygen makes fast regeneration of a filter possible, it also contributes to runaway regeneration problems.

Some applications use off-lath regeneration. Off-board regeneration requires operator intervention (i.e. the car is either plugged into a wall/floor mounted regeneration station, or the filter is removed from the machine and placed in the regeneration station). Off-board regeneration is not suitable for on-road vehicles, except in situations where the vehicles are parked in a central depot when not in use. Off-board regeneration is mainly used in industrial and mining applications. Coal mines (with the bellboy explosion risk from coal damp) utilise off-board regeneration if non-disposable filters are installed, with the regeneration stations sited in an expanse where not-permissible mechanism is immune.

Many forklifts may as well use off-lath regeneration – typically mining machinery and other mechanism that spend their operational lives in one location, which makes having a stationary regeneration station practical. In situations where the filter is physically removed from the machine for regeneration at that place is besides the advantage of being able to inspect the filter core on a daily basis (DPF cores for non-road applications are typically sized to exist usable for one shift - so regeneration is a daily occurrence).^[44]

Come across besides [edit]

• Air pollution
• Selective catalytic reduction
• Smog
• Ultra-low sulfur diesel

References [edit]

1. ^ Tom Nash (May 2003) "Diesels: The Smoke is immigration", Motor Vol.199 No. five, p. 54, Hearst Concern Publishing Inc.
2. ^ ^{a b c d east f g} Emission Technology: DPF - Diesel Particulate Filters, Axces.eu
3. ^ Jong Hun Kim et al. (November 2010) "NO2-Assisted Soot Regeneration Behavior in a Diesel Particulate Filter with Heavy-Duty Diesel Exhaust Gases", Numerical Heat Transfer Part A Vol.58 No.9 pp.725–739, Chonbuk National Academy, Korea doi:ten.1080/10407782.2010.523293
4. ^ ^{a b c} "DPF Maintenance" (January 2010) HDT Trucking Info
5. ^ "Diesel fuel dilemma" (7 Nov 2011) BBC News
6. ^ "DPFs reduce diesel soot emissions by 80% but they're not suitable for everyone" (v Dec 2013) The Automobile Clan
7. ^ "Report: 'Clean fuel' non always successful" (March 1, 2011) UPI NewsTrack, Vancouver, British Columbia
   "Canadian researchers say a program past one of the world's largest cities [New Delhi] to switch its vehicles to clean fuel has not significantly improved emission levels."
8. ^ "Emissions from new diesel cars are still far higher than official limit". TheGuardian.com. thirty August 2016.
9. ^ ^{a b} Barone et al. (August 2010) "An analysis of field-aged diesel particulate filter performance: particle emissions before, during, and later on regeneration", Journal of the Air & Waste Management Association Vol. 60 No.8 pp. 968-76 doi:10.3155/1047-3289.60.8.968
10. ^ DPF - Diesel Particulate Filters, Axces.eu
11. ^ Vincent D. Blondel: Recent Advances in Learning and Control, p. 233, Springer Science & Business Media, 2008, ISBN 9781848001541
12. ^ Diesel Particulate Regeneration
13. ^ ""Avant-garde Diesel Particulate Filters And Systems For Exhaust Cleaning", Huss LLC" (PDF). Archived from the original (PDF) on 2014-09-06. Retrieved 2014-09-05 .
14. ^ ^{a b} Bahadur et al. (2011) "Touch of California'due south air pollution laws on black carbon and their implications for direct radiative forcing", Archived 2014-09-06 at the Wayback Machine Atmospheric Environment Vol. 45 pp. 1162–1167, Scripps Institution of Oceanography, Academy of California San Diego
15. ^ Worldwide emission standards for diesel fuel vehicles and engines
16. ^ James Scoltock (June 2014) "Diesel Particulate Filter: PSA Peugeot Citroën was the first to bring in particulate filters to help brand diesels cleaner", Automotive Engineer p. 9
17. ^ "Frequently Asked Questions - Heavy-Duty DECS Installation and Maintenance". Retrieved 28 October 2011.
18. ^ American Recovery and Reinvestment Act Archived 2014-09-05 at the Wayback Car
19. ^ ""Technology from BASF makes Hong Kong's air cleaner" (April 02, 2008) BASF The Chemical Visitor". Archived from the original on September 23, 2015. Retrieved September 5, 2014.
20. ^ "In Introducing Diesel Vehicle Command" (PDF). Archived from the original (PDF) on 2012-10-30. Retrieved 2014-09-05 .
21. ^ "Cleaning Up Diesel Emissions in United mexican states City" (July 12, 2012) EPA
22. ^ "New York City passes diesel emissions rules" (Apr 21, 2005) FleetOwner
23. ^ "Milan's Ecopass To Evolve" (September ii, 2011) Italy Chronicles
24. ^ Low Emission Zone, Ship for london
25. ^ Fit a Filter, Transport for london
26. ^ "Pass Your 2018 MOT - New Rules Regulations
27. ^ "Europe Bans Diesel for Cleaner Air - Fixter Web log". Fixter Blog. 2018-07-12. Retrieved 2018-07-26 .
28. ^ "Laissez passer Your 2018 MOT - New Rules & Regulations - Fixter Blog". Fixter Blog . Retrieved 2018-07-26 .
29. ^ Diesel fuel particulate Matter – Emission Reduction Methods Archived 2012-10-17 at the Wayback Machine (2009) Mine Prophylactic and Health Administration (MSHA), U.Southward. Section of Labor]
30. ^ Particulate emissions from diesel engines: correlation betwixt engine technology and emissions
31. ^ DPF (Diesel Particulate Filters) Explained
32. ^ "Technical Papers" (2013) Corning Environmental Technologies
33. ^ "Cordierite" (2009) Diesel fuel Emission Technologies Inc.
34. ^ ^{a b} "Silicon Carbide (SiC)" (2009) Diesel Emission Technologies Inc.
35. ^ "Metallic Fiber & Mesh Filters" (2009) Diesel Emission Technologies
36. ^ "Best Practices For Underground Diesel Emissions" - CDC Stacks
37. ^ Technology Guide, DieselNet
38. ^ Jacobs et al. (2005) "Evolution of Fractional Filter Engineering science for HDD Retrofit", SAE International
39. ^ Kamp CS, et al. (April 2016). "Ash Permeability Determination in the Diesel Particulate Filter from Ultra-Loftier Resolution 3D X-Ray Imaging and Image-Based Straight Numerical Simulations". SAE International. 2017-01-0927 (2): 608–618. doi:x.4271/2017-01-0927.
40. ^ "Ford recalls F-150s over tailpipe fire fear" (March 21, 2007) NBC News
41. ^ "Jaguar S Blazon XJ diesel fuel particulate filter recall" (22 Mar 2007) CarAdvice
42. ^ "Hino Standardized SCR Unit". Hino Motors. Archived from the original on 5 August 2014. Retrieved 30 July 2014.
43. ^ "The DPR Future" (PDF). Hino Motors. Retrieved xxx July 2014.
44. ^ Bruce R. Conrad Archived 2006-09-02 at the Wayback Machine, "Diesel fuel Emissions Evaluation Program - INCO" Diesel Emissions Evaluation Program Website (May 2006)

External links [edit]

What Is A Particulate Filter,

Source: https://en.wikipedia.org/wiki/Diesel_particulate_filter

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