![\"Combustion-related](\"https:\/\/fleetimages.bobitstudios.com\/upload\/trucking-info\/content\/article\/2021-01\/hdt-jan21-dpf-2-chevron-__-720x516-s.jpg\"){kind=icon}
If that ash is not manually removed regularly from the tiny channels within the filter core, it packs in tighter and tighter. Eventually it turns into a concrete-like substance that will, over time, significantly reduce the carrying capacity of the DPF, shortening the backpressure-induced regen intervals. And the high-temperature regens can actually accelerate this \u201csintering\u201d of the ash, compounding the problem.<\/p>\n
\u201cThe DPF pressure differential sensor doesn\u2019t know the difference between ash and soot. It just knows that the backpressure is higher, and that triggers a regen,\u201d says Jeremy Anderson, national sales manager for DPF cleaning machine producer FSX. \u201cBecause the ash is taking up space in the DPF, it can\u2019t inventory as much soot before the pressure differential sensors go off and start another regen. When the time between regens starts to shorten, you know it\u2019s time to service the DPF.\u201d<\/p>\n
Servicing vs. Replacing DPFs<\/h2>\n
There\u2019s some confusion surrounding the need for hands-on maintenance of the DPF. Doing a regen isn\u2019t the same as de-ashing the DPF with a cleaning procedure. And that\u2019s not the same as ditching the DPF and exchanging it for a new or reconditioned unit.<\/p>\n
\u201cWhen the OEMs talk about high-mile DPF service intervals, they are using the best-case scenario: trucks that run heavily loaded in high-mile, on-highway applications where passive regeneration can deal with soot loads in the DPF,\u201d says Steve Hoke, president of aftertreatment service center Diesel Emissions Service.<\/p>\n
However, high rates of passive regeneration do little to solve the buildup of ash, which accumulates as oil is consumed.<\/p>\n
\u201cAll the unburned blow-by oil, fuel droplets, and stuff that isn\u2019t atomized in the cylinder goes out the exhaust,\u201d Hoke says. \u201cPre-2007, it was no big deal. All that stuff just disappeared. But now it doesn\u2019t.\u201d In an ideal world, he explains, it goes through the oxidation catalyst, which oxidizes the soot as it goes through, and all the DPF sees is clean, light, fluffy ash.<\/p>\n
\u201cBut in the real world, the efficiency of the DOC drops over time because it\u2019s poisoned by coolant and oil leaks, etc. An older DOC might be no more than 50% to 70% efficient in its capacity for oxidizing soot, so you have more unburned particulate or unoxidized soot going into the face of the DPF.\u201d<\/p>\n
So even in the best-case scenario, as the truck ages, there\u2019s a good chance that ash, not soot, is mucking up your DPF \u2014 and all the regens in the world won\u2019t make it go away.<\/p>\n
Removing the DPF from the truck and having it cleaned is about the only way to deal with ash. Lots of shops and most dealers provide the service, and some large fleets buy their own cleaning machines. It\u2019s usually an overnight job, but depending on the volume at the shop, it can stretch to a couple of days.<\/p>\n
A popular alternative when uptime is critical is to buy a replacement new or reconditioned DPF.<\/p>\n
\u201cReplacing the original with a reman can get you back on the road in a few hours,\u201d says Anderson. However, he notes, \u201ca reman DPF will cost you about three times as much as a cleaning, and you won\u2019t know anything about the history of the reman filter, other than it\u2019s covered by some warranty.\u201d<\/p>\n
DPF Cleaning Methods<\/h2>\n
Cleaning a DPF usually involves removing the filter from the truck and using a high-pressure, high-volume \u201cair knife\u201d to loosen material from the tiny channels within the DPF. Next, the filter is flow-tested to check the level of restriction still present. Several individual channels are measured with a length of wire to see if any material remained behind. A high degree of remaining material may require the DPF to be \u201cbaked,\u201d exposed to very high temperatures for up to eight hours, to further reduce the residue to a finer, looser material that can be blown out.<\/p>\n DPFs are baked for several hours at high temperatures to remove entrained sintered ash. Credit: FSX<\/p>\n<\/figcaption><\/figure>\n Daimler Trucks North America, however, does not endorse the so-called \u201cbake and blow\u201d cleaning method, saying it does not clean the DPF as thoroughly as a liquid wash.<\/p>\n \u201cWe designed our DPF to be liquid cleaned,\u201d says Len Copeland, Detroit product marketing manager at DTNA. \u201cWe recommend that our customers run their DPFs through our reman program. The DPFs are washed and serviced, and the customer can just swap out the old DPF for a clean one and they are on their way with minimum downtime.\u201d<\/p>\n Detroit\u2019s system is set up to throw an ash cleaning code after the truck has burned a certain amount of fuel, based on the application. When the ash accumulator is reset, it assumes that the customer has installed a reman filter and resets the cleaning interval to the prescribed number.<\/p>\n Diesel Emissions Service is offering a new process, saying it can do an aqueous wash of the DPF using a surfactant to remove sintered ash during the time the truck is down for an A-service preventive maintenance service, with an oil change, etc. DES has begun selling the machines to its core customers and fleets will soon be able to acquire them for use in their own shops.<\/p>\n \u201cWhen done according to our recommendations, this process will produce the same results as an overnight \u2018bake-and-blow\u2019 cleaning, but in about two hours,\u201d Hoke says. \u201cThe service is available in our shops now, but you\u2019ll pay more for it than you would a traditional cleaning. The obvious advantage is the fast turnaround time.\u201d<\/p>\n The process doesn\u2019t cut corners, and it\u2019s not a shortcut to the next cleaning interval, Hoke says. \u201cOur new aqueous process is subject to all the same standards as a bake-and-blow cleaning. It goes by the same flow numbers, the same weighing process. It passes or fails based on the same specs.\u201d<\/p>\n Anything that goes through the combustion chamber is going to wind up the DPF eventually. Oil, coolant, even dust from the air intake can foul the filter substrate. Coolant and oil are among the worst, because they coat the face of the DPF and lower its efficiency. Excess fuel from a failed injector can raise soot levels dramatically, but there are no longer any visible symptoms. Any upstream failure should be a red flag to check the DPF too, Hoke says.<\/p>\n It\u2019s hard to track drivers adding make-up coolant or oil to the engine, but if they are doing so, it suggests the fluids are going somewhere \u2014 possibly into the DPF. Drivers should be told to advise maintenance when they are topping off fluids so consumption can be tracked.<\/p>\n \u201cThe worst case would be a turbo failure,\u201d says Anderson. \u201cThat will torpedo an entire aftertreatment system very quickly.\u201d<\/p>\n Various DPF failure modes have signature appearances. A well-trained eye can tell at a glance what has gone wrong. Photo: Webasto<\/p>\n<\/figcaption><\/figure>\n EGR failures are also responsible for a number of DPF issues, but cleaning and servicing the EGR system can be expensive and time-consuming. According to Hoke, just removing the EGR coolers from one brand of engine is a nine-hour job. Add nine more hours for reassembly and the time it takes for cleaning, and it\u2019s easy to see why fleets avoid it.<\/p>\n Hoke offers a service where the EGR system can be cleaned while the truck in in the shop for regular service without removing the coolers and valves.<\/p>\n \u201cThe process is completely self-contained,\u201d he says. \u201cAfter removing the aftertreatment system, you hook the machine up to the air intake system and run a few liters of cleaning and flushing solution through the engine while it\u2019s running. It takes about 30 to 45 minutes and costs about 500 bucks parts and labor.\u201d<\/p>\n The DPF\u2019s ability to passively oxidize soot is highly dependent on exhaust temperature. Exhaust from lightly loaded engines or trucks that idle a lot isn\u2019t hot enough to efficiently oxidize the soot. Cold-weather operations can further reduce the efficiency of the aftertreatment system.<\/p>\n \u201cEach fleet is going to have their own sweet spot, so to speak, upon which the preventative maintenance schedule should be based,\u201d says Anderson. \u201cIt should not be based on a pre-determined timetable, but based on the routes, the trucks, the engines, the loads, and the drivers. All those variables play a part in determining the optimum cleaning intervals.\u201d<\/p>\n Fleets have spent years streamlining their preventive maintenance processes, but because aftertreatment maintenance can\u2019t be based strictly on a one-size-fits-most mileage recommendation, fleets have to learn to restructure the PM if they want to reduce DPF headaches.<\/p>\n Anderson strongly recommends setting up alerts in a fleet\u2019s maintenance management system to flag when the regens are becoming more frequent. Barring that, get drivers to report regen events so they can be tracked and regen histories built around the data.<\/p>\n Darry Stuart, an independent \u201climited-time executive\u201d who provides maintenance and operational expertise for dozens of fleets, says the 2.5-hour PM is a thing of the past.<\/p>\n Among other things, DPF canisters should be inspected regularly for possible damage, cracking, and breakage. He also suggests inspecting and cleaning the sensors and their exposed contacts to ensure they have good electrical connections and are not gummed up by contaminants that could cause false fault codes.<\/p>\n \u201cWe\u2019re just now beginning to accept that we have to do things differently from what we have been doing all our lives in order to maintain the aftertreatment system,\u201d he says.<\/p>\n The new lower-ash CK-4 engine oils contain about 1% ash by volume, but Chevron\u2019s new Delo 600 ADF<\/a> is said to contain just 0.4% ash. It also contains no zinc or phosphorus in the additive package \u2014 both at least partially responsible for ash buildup in DPFs. According to Jason Gerig, commercial on- and off-highway sector manager for Chevron Lubricants, Americas, this low-ash engine oil can reduce ash buildup in the DPF by a significant margin.<\/p>\n \u201cWe have used a CT scan machine to observe the ash content of in-service DPFs,\u201d he says. \u201cWith typical CK-4 oils, we\u2019ll see about 1 millimeter of ash buildup for every 10 to 20 hours of operation, generally speaking. But with Delo 600 ADF, we see that same 1 millimeter of ash for 100 to 800 hours of operation.\u201d<\/p>\n Fleets can avoid self-inflicted wounds by steering clear of cheap, off-brand oil as make-up oil. If the truck is consuming oil, it\u2019s probably winding up in the DPF as ash, coating the diesel oxidation catalyst and the DPF face. Low-ash oils such as Delo 600 ADF may still wind up in the DPF, but it won\u2019t cause as much ash buildup, Gerig says.<\/p>\n During a cold start, diesel engines pass a lot of unburned fuel through the exhaust system. In pre-DPF days, cold starts produced clouds of smoke when they were first cranked to life. They still do that, but you can\u2019t see the smoke \u2014 because it\u2019s trapped by the DPF.<\/p>\n The solution, according to Webasto, is to preheat the engine before starting. The company has been researching diesel-fired engine coolant heaters since before DPFs were mandated in 2007. Findings show that warming the engine coolant to 165 degrees before turning the key reduced soot by about 66% at a 40-degree ambient temperature, and by 27% at a 70-degree ambient temperature.<\/p>\n \u201cWe saw a significant reduction on [preventive maintenance] when we preheated the engine using a coolant heater, but we saw other benefits, too,\u201d says Duane Bratvold, western regional business development manager for Webasto Thermo & Comfort North America. \u201cDepending on the outside temperature, it can take 35 to 45 minutes for the DPF to heat up enough to start oxidizing soot. By preventing much of the cold, damp soot from getting into the filter in the first place, the DPF has a chance to heat up like it\u2019s supposed to before it\u2019s overloaded.\u201d<\/p>\n Bratvold explains that coolant heaters left running on equipment with frequent on and off cycles, such as yard trucks or food-service delivery trucks, can help keep engines closer to normal operating temperature when they are restarted, lowering soot production. \u201cThey are also great alternatives to idling for all the same reasons,\u201d he says. \u201cIdling kills DPFs.\u201d<\/p>\n Biodiesel supplier Renewable Energy Group claims that burning biodiesel emits less particulate matter than petroleum diesel, yielding fewer regens and less maintenance on the aftertreatment system. According to REG, the oxygen in biodiesel provides more complete combustion and produces 50% less soot than petroleum diesel.<\/p>\n \u201cLess soot means the DPF fills slower, resulting in fewer regens,\u201d REG told us. \u201cAlso, biodiesel particulates burn off easier than those from ultra-low-sulfer diesel.\u201d<\/p>\n<\/div>\n Originally posted on Trucking Info<\/a><\/p>\n <\/p>\n by Chris Brown<\/a><\/p>\n<\/div>\n https:\/\/plus.google.com\/112966626995148870245<\/a><\/p>\n<\/div>\n<\/div>\n Chris Brown is the executive editor of Business Fleet,\u00a0Auto Rental News\u00a0<\/em>and Fleet Forward<\/em>. Through these publications, online newsletters, trade events, and associations, Chris covers all aspects of the fleet world, including fleet management, the new mobility ecosystem, manufacturer fleet activities, the fleet leasing industry, vehicle remarketing, rental industry news, car rental taxation and legislation as well as automotive environmental initiatives and trends.\u00a0Chris produces the International Car Rental Show and the Fleet Forward Conference. Chris is relied on as industry resource in matters relating to car rental by major media outlets such as the Washington Post, New York Times, Forbes, Wall Street Journal,\u00a0and National Public Radio.<\/p>\n <\/p>\n<\/div>\n<\/div>\n Source: https:\/\/www.businessfleet.com<\/a><\/span><\/p>\n<\/div>\n The audit is a key tool to know the overall status and provide the analysis, the assessment, the advice, the suggestions and the actions to take in order to cut costs and increase the efficiency and efficacy of the fleet. We propose the following fleet management audit.<\/p>\n Photo: Jim Park We\u2019re just now beginning to accept that we have to do things differently from what we have always done in order to maintain our aftertreatment systems. We\u2019ve had 14 years to figure it out, yet diesel particulate filter maintenance remains a nightmare for many fleets. Why do DPFs elicit such gnashing of…<\/p>\n","protected":false},"author":3,"featured_media":9496,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[53],"_links":{"self":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/9495"}],"collection":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/comments?post=9495"}],"version-history":[{"count":2,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/9495\/revisions"}],"predecessor-version":[{"id":9498,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/9495\/revisions\/9498"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/media\/9496"}],"wp:attachment":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/media?parent=9495"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/categories?post=9495"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/tags?post=9495"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"DPFs](\"https:\/\/fleetimages.bobitstudios.com\/upload\/trucking-info\/content\/article\/2021-01\/hdtjan21-dpf-4-fsx-inc--__-720x516-s.jpg\")
Upstream Failures<\/h2>\n
![\"Various](\"https:\/\/fleetimages.bobitstudios.com\/upload\/trucking-info\/content\/article\/2021-01\/hdtjan21-dpf-5-webasto--__-720x516-s.jpg\")
Rethinking Diesel Particulate Filter Maintenance Schedules<\/h2>\n
3 Ideas for Getting Ahead of DPF Buildup<\/h2>\n
\u00a01. Use a low-ash engine oil <\/strong><\/h3>\n
2. Preheat your engine with a coolant heater<\/strong><\/h3>\n
\u00a03. Try biodiesel<\/strong><\/h3>\n
![\"Chris](\"https:\/\/fleetimages.bobitstudios.com\/upload\/authors\/cbphoto862014-thumb-__-100x100-a.jpg\")
<\/figure>\nChris Brown<\/h1>\n
Executive Editor<\/h3>\n
CUT COTS OF THE FLEET WITH OUR AUDIT PROGRAM<\/strong><\/a><\/h3>\n
![\"\"](\"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-content\/uploads\/sites\/3\/2020\/04\/nueva-ley-auditoria.jpg\")
<\/a><\/p>\nFLEET MANAGEMENT AUDIT<\/strong><\/a><\/h3>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"