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what are your feelings about the DEF exhaust system on a Fire Apparatus
We purchased a new 2013 Kenworth 2000 gallon Tanker. We picked it up in Dec of 2012 and wasn't able to use it until March 2013 due to a problem with the DEF system. we took it to 5 different places via the dealers request. We are a small dept and only run about 120 responses a year. we have a lot of area and a major highway that runs through it. We were told that we had to run the truck for about 30 minutes at normal speed on the open highway once in a while. We did this once a month and it hasn't helped our tanker is back in the dealers shop for the same reason DEF System. I have asked surrounding Departments about their trucks. they had some problems also and a couple Departments have had to run their trucks once a week for the 30 minutes or more. With the cost of fuel and man hours that have to go into trying to prevent this problem it is to much for volunteer and paid departments to have to pay. I feel that it should be taken to proper authorities to develope a bill to allow all Fire Apparatus to be exempt from this regulation. What is your opinion?
Replies to This Discussion
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Permalink Reply by ashfire on
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I work for our county public works and many of the new small and large diesel trucks are using DEF and we have had to stock both jugs and 55 gal barrows which uses a portable pump station in our repair garage to keep these vehicles running. One day I walk into my volunteer fire station and there is a 55 gal barrow of DEF sitting at the door and its for our new Pierce Ladder Truck. It was a week before they got a electric pump to pump the fluid into the truck. I have heard that they have to pull the truck out on the ramp and run it for 30 min after they fill it. This is done by the career crew on duty around the clock.
I know it is a pain to have to store DEF and have enough on hand.
The same building I work in transportation bus operation have a wash bay and they have a large storage tank in there and they have bulk delivery and fill the buses at the end of the day when they run them trough the wash bay.
There was discussions to have tanks and pumps for DEF at all county gas and diesel pump stations around the county but that has been put on hold until there is money for it.
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Permalink Reply by Larry Curtis on
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Thank you. Having the DEF fluid isn't the problem. we are constantly getting a service code to service the def system. we don't use this fire truck enough to do it every day or week. there may be 2 or 3 weeks in between runs. other fire departments are also having this problem. as I see it ,the engine is suppose to slow down if the system is acting up and needs servicing while on an emergency. being a fire truck it could cause big problems if we are at a fire and in need of the 2000 gallons of water it is caring to us. this is one reason that emergency equipment shouldn't have this system.
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Permalink Reply by Marc Hansen on
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Larry,
Try this link see if it helps.
http://www.iafc.org/files/1EVM/FAMA_EmerVehEmissionsSysGuide.pdf
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Permalink Reply by Jason Hawes on
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The diesel federal emission standards changed in 2007.5 which required the addition of particulate filters to meet those requirements and in 2014 the standards rose yet again, forcing most the MFG's to implement DEF into the emission systems.
After the addition of particulate filters, vehicles have to go into a REGENERATION MODE where extra fuel is used to super heat the exhaust to burn off the garbage caught in the filter. This system works for commercial vehicles that spend hours operating at freeway speeds every day but can cause problems for private vehicles and fire engines as they may or may not operate at freeway speeds for a long enough period for the REGEN to complete. This system was extremely problematic in the beginning and has improved with software programming. These engines also have seen a noticeable loss in fuel mileage since it consumes more fuel for the REGEN MODE.
DEF (Diesel Exhaust Fluid) was implemented to take the place of the extra diesel fuel used for REGEN. Basically, the exhaust system works similarly to the 2007.5 + engines. Programming and design improvements have allowed these engines to work more efficiently under less than ideal conditions but still require some sort of REGEN. These engines have slightly improved fuel milage but the savings are ate up in DEF.
If the REGEN is not completed with a plugged particulate filter the engine can go into LIMP or SERVICE MODE on some models, rendering it useless. For us Firefighters and EMS personel, LIMP MODE could be catastrophic.
I've owned diesel powered pickups since 1992 so my opinion probably doesn't hold merit in this topic. However, I will make note that a lot of private and commercial vehicles have suffered expensive exhaust failures and problematic engines codes since 2007.5. I'm all for clean air but if hampers our efforts to save life and property, I'm hoping the Feds can make an exception for the Fire Dept and EMS services.
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Thank you this is what I'm saying. out truck has spent more time in the repair shop than in our station. it is there now and they don't know what to do..apparently they have called their tech line for help also. again we need our emergency vehicles to be exempted from this. tks
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thanks I have passed this to our Chief
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Permalink Reply by Kevin Fox on
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It sounds to me like you may have some bad information on how the DEF/Regen works on a truck.
First off, you can only do a regeneration on the truck when the vehicle calls for it. It should give you an indicator light on the dash. Once the truck calls for a regen, you can do it one of two ways. You can do a "passive" regeneration by driving it for 30 to 40 minutes at highway speeds until the light goes off or you can do a parked regeneration.
Regardless of what type of regen you are doing, 3 criteria must be met for it to successfully regenerate.
1) The vehicle must be calling for a regen. (light is on)
2) The engine RPM's must be over 1000
3) The engine temperature must be 175 degrees or higher.
If you are in the process of doing a regeneration and a firecall comes in, it's ok to stop the regen and drive it to a call. All that it will do is shorten the time before the next regen is required.
I could go deeper into the different stages of regen if you ignor the initial regen warning light, but you may have better luck doing some searches on the Kenworth regeneration system.
I hope this helped, and good luck.
I hope this has helped.
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thanks for the reply. we have done both ways. it is in the shop now and they don't know what to do with it either. Kenworth techs are working on the problem also. the service light keeps coming on and won't go away. I still feel that it should be exempted from emergency vehicles. tks
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I agree....The regeneration process for fire apparatus is always troublesome. These vehicles spend the majority of their lives driving short distances and idling for long periods of time, which is hard on the exhaust filtering systems.
Unfortunately even exempting them may not help since the motor manufufactures may not want to tool up their lines for both style of motors. The fire service just doesn't count for a big enough share of their market.
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Larry,
Instead of talking to Kenworth your people should be talking to the engine manufacture (detroit, cummins..etc). They are the ones that set the program for the computer and developed the exhaust filtration system used.
One other benefit to talking to the engine people is, that due to the custom nature of fire trucks there may have been a design change by kenworth that negates somethng in the exhaust regen. Remember the problem of Ford Explorers rolling over all the time, that was caused by the manufacturer using tires at lower pressure then the tire manufacture designed them for. You may have the same type of problem going on here.
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thanks Keven, maybe with all our commits it might help in the future. if we don't say anything then the powers to be might not understand our problems.
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Thanks Marc, both Cummings and Kenworth are working on our problem at this time but I think that the EPA regulations may have something to do with it also. I feel that emergency vehicles really should be exempted from having to use a regen system due to the the specific use of emergency vehicles, some are used many hours while some are short and not enough time to do a regen. yes we take the truck out every month and some of the surrounding depts have to take theirs out every week and run it on a 4 lane hwy so it can run it's program. Both companies have checked the software and made changes, the control center (computer) has been replaced and re-programed several times .. it's costly for us having to pay for fuel and being a volunteer dept, man power to run it to the shops and monthly runs etc... $170,000 financed for several years adds up for some thing that isn't reliable, remove this system and the problem should be gone also. Thank you for your reply.
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