Experience with new SCR engines?

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Oram, Sep 8, 2012.

  1. Cat sdp

    Cat sdp . .

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    I have a dumb question . You park your new 2013 truck and shut it off, it's -20f outside. Not to worry the truck is plugged in and in my case it would be in my driveway. So the def fluid freezes.
    I know the def tank has a heating element , but there is no way that fluid is ready to go when you start out on a morning at -20. So your spewing out exhaust that does not meet the emissions regs , or do I have it all wrong?
     
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  3. Sportster2000

    Sportster2000 Road Train Member

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    The EPA mandates that the DEF has to thaw within a certain amount of time for the engine to stay complient with the regulations. For a while the engine is cold enough that it won't put out that much nox. Once it is warm then yes you are right it will be putting out more nox than allowed but there are times when the EPA decided that it was allowable and that is one of those times.
     
  4. durallymax

    durallymax Medium Load Member

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    Not really wrong at all.

    When the engine is cold and idling, the NOX emissions are very low to begin with. Particulate emissions are the main concern then.

    However like you state, the fluid will not thaw immediately. The fluid is cooled either with coolant or with an electric heater. For ones using coolant heaters the engine goes into a fast warmup mode generally.

    The EPA allows 30 minutes for off road engines to thaw the DEF before it will de-rate the engine. What the exact rule is for on road engines I cannot remember.
     
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  5. carrkool

    carrkool Heavy Load Member

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    def thaws fast. when you start the truck the heater comes on. by the time the motor has warmed up and requires a burn off the def tank is thawed. i think the tested showed a completely gelled 18 gallon( the big tank) thawed in just under 30 minutes. remember the def does not flow or run all the time. only when the burn chamber reaches a certain sutt level. than it turns on and burns off the camber.
     
  6. carrkool

    carrkool Heavy Load Member

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    these new motors are so bad that the days of glider kits have come back. frieghtliner has been offering new trucks with 12.7 litter detroits for some time now. Also to the guy who said i was full of it. Def motors which frieghtline calls the SCR system burns at 2500 to 3000 degress F. So hot infact after the first year they had to redesign the system to move it back and away from the turbo because the where wiping turbos out from heat damage. They had the same effect as the old trucks that we added spark plugs to the tips to flame the stacks showing off. burnt oil....When i first heard of this i was driving a temp truck. a frieghtliner cascada hunk of junk...lol i could not believe it either. I pulled a refeer and had a infred temp gauge. I shot the burn chamber and got a reading of 2350 degrees. that right under the bunk area about where the curtain on the pass side hangs...i was told about this because i was talking with some guys and said how i could not keep a drink cold sitting on the floor. how a new cold drink was like a fresh cup of coffee in about an hour...
     
  7. highside

    highside Medium Load Member

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    Buddy, you need to go back and learn how these things REALLY work, instead of mis-informing people who are uneducated on the matter, and come here for help.

    The DEF pump doesn't come on only when a certain soot level is reached. That's an active regen, and it's when the doser injector is turned on.

    The DEF pump operates whenever the engine is running. The amount of DEF injected is based on how much NOx is being detected in the exhaust gas by the NOx sensor. DEF is always being injected, just at varying rates. Rule of thumb is DEF consumption is roughly 2 -3% of fuel consumption. It is correct that the ECM allows for a certain amount of time for frozen DEF to thaw before setting a fault code.

    I find it extremely difficult to believe that a drink left on the floor of your truck will get as hot as a cup of coffee after just an hour. If that were truly the case, you'd never need a heater in the winter, but one hell of an air conditioner in the summer.
     
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  8. DrtyDiesel

    DrtyDiesel Road Train Member

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    I have a dpf only maxxforce. The floor gets hot but DEFINITELY not that hot. All it did was make my soda Luke warm.

    Ethan
     
  9. durallymax

    durallymax Medium Load Member

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    You have to figure in the trucker talk exaggeration rate. Many times people do experience things, however do to their poor grammar, lack of knowledge on what any of the systems do or how they function and the exaggeration they have along with their sources of "hearsay" , they loose credibility to some people. The big issue is that many others don't know any better either and believe these claims and add in their own exaggeration. Suddenly a system that starts passively regenerating at 600* and during an active Regen is forced to 1200* turns into a system operating at temperatures that would melt through the exhaust system and melt the catalysts inside the chambers.

    Sent from my SCH-R530U using Tapatalk 2
     
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  10. durallymax

    durallymax Medium Load Member

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    You need to check your facts before posting about how the system works. A simple Google search would've set all of your statement s straight.

    For the umpteenth time the SCR system has no direct relationship with the DPF system. There is no burn off for the SCR system. Furthermore the SCR system is not a filter rather it's a chemical reaction.

    SCR is the acronym for Selective Catalytic Reduction. That is the industry standard not a brand name. It is not feeightliners name. They don't call DEF SCR because the two are not an interchangeable term. DEF is the ingredient needed for the SCR system to function.

    Glider kits have been around for a long time. Some are becoming more popular but the latest generation of trucks are running better and for anyone other than a small fleet or owner/operator the hassle of a glider doesn't pencil out.

    The DEF is injected as needed.

    The DPF active regeneration process heats the DPF to 1200* F at the inlet. The 3,000* temperatures you are claiming would melt the exhaust components.
     
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  11. DrtyDiesel

    DrtyDiesel Road Train Member

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    I think even Wolverine's bones from xmen wouldn't stand up to 3,000°F.



    Ethan
     
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