What is diesel exhaust fluid?

[B Hoofed]

The DEF is injected into the exhaust to reduce NOx emissions, how do you figure it increases mileage if it is used post detonation?

Edit: nevermind, I see that it can allow the engine to be tuned different....do you really see an appreciable difference in mileage?

I see 2 or 3 mpg on average improvement compared to previous 6.4L Powerstorke that had a diesel particulate filter, but did not use DEF. This is for a truck that has 50 more horsepower and 150 ft. Lb. more torque compared to the previous model. The EPA tightened the NOx emissions requirements in 2010, so the fuel economy would have been a lot worse with the engine running really rich and using a lot more EGR to prevent NOx formation. This generates a lot of soot, which requires frequent regeneration of the particle filter. The DEF addition in the exhaust allows the engine to run leaner and at higher combustion temperatures, which is more efficient. The DEF takes care of the higher NOx levels that are formed as a result of running the engine more efficiently.

 

[art]

For us that work with the big tractors basically coming from the last round of emmision cuts tier III where everyone was able to clean up to pass by retarding the timing. For tier IIII the fluid has allowed those that chose to go with it to advance the timing and gain power and fuel economy. Deere didn't and currently is recalling large tractors to add it to get back into the market again.

 

[k0ua]

For us that work with the big tractors basically coming from the last round of emmision cuts tier III where everyone was able to clean up to pass by retarding the timing. For tier IIII the fluid has allowed those that chose to go with it to advance the timing and gain power and fuel economy. Deere didn't and currently is recalling large tractors to add it to get back into the market again.

Art, maybe you can answer this, the thing that concerned me the most about DEF is the fact it freezes at 12 deg. F.. so the truck uses battery power to maintain a small heater to prevent freezing?. that seems like a big problem to me. How is that going to work for a 40 horse CUT that might sit for a month in the winter without starting? I don't understand this
Thanks

James K0UA

 

[PoorPlowboy]

DEF is stored in a tank on board the vehicle, and injected into the exhaust stream by a metering system at a rate of 2% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimises the tank's obtrusion into vehicle packaging space. An Electronic control unit adjusts the addition of fluid in accord with such parameters as engine operating temperature and speed.

Diesel Exhaust Fluid is offered to consumers through a variety of quantities by manufacturers ranging from containers of it for single or repeated small usage to bulk carriers for consumers that require a large amount DEF. It's recommended that it be stored in a cool, dry, and well-ventilated area that is out of direct sunlight.

copied from wikipedia

Obtruding tank? I guess wiki hasn't seen a new Duramax with it's belly dragging on the passenger side behind the front wheel. Luckily the aftermarket is there to meet our demands...

Skyjacker DEF Tank Skid Plate for Duramax Diesel

 

[Code54]

We have a 2011 F350 diesel that uses DEF. It's really no problem at all to deal with. The tank holds 10 gallons, which is enough for 5-10 thousand miles depending on the type of driving. It's easy to fill the tank and you can get a 5 gallon bottle for $10 - $15 at most auto parts stores or Walmart. The DEF allows the truck to get much better fuel economy, which outweighs the additional cost of the DEF. The only negative I see is added complexity to an already complex powertrain, and one more system to fail. The early 6.7 powerstrokes have had some issues with DEF pumps and sensors failing.

WOW, you are doing a lot better than us in WV - we pay about $6-$7 a gallon around here. Even Wal-Mart is $13.99 for 2.5 gallons, you got a deal.
It seems it is not a bad way to go, they say it costs about $.01 a mile, which is not too bad. My truck does a Regen where it allows fuel to go in to the exhaust system and burn the soot out of the DPF. I am sure that costs me more in fuel than the DEF.....

 

[swines]

Art, maybe you can answer this, the thing that concerned me the most about DEF is the fact it freezes at 12 deg. F.. so the truck uses battery power to maintain a small heater to prevent freezing?.

It doesn't really freeze at 12F - it gets slushy. There is a heater in the tank and the DEF lines and both are heated when the truck is started. The truck runs without DEF injection in the exhaust until the DEF is liquid and will flow through the DEF lines. My understanding, from talking with a Ford tech, is that it takes about 10-15 minutes after the truck is started to get DEF liquid at 0F. I've had no trouble with my 2011 F350 in the 2-1/2 years I've owned it.

 

[SPYDERLK]

WOW, you are doing a lot better than us in WV - we pay about $6-$7 a gallon around here. Even Wal-Mart is $13.99 for 2.5 gallons, you got a deal.
It seems it is not a bad way to go, they say it costs about $.01 a mile, which is not too bad. My truck does a Regen where it allows fuel to go in to the exhaust system and burn the soot out of the DPF. I am sure that costs me more in fuel than the DEF.....

Would water work?

 

[WD40]

118Pilot Travel CenterI-30, Exit 121Benton AR, US$2.7998

You may want to check the Pilot Truck stop near you but it, $279.9 here in Benton, AR.
Doug

 

[WD40]

118Pilot Travel CenterI-30, Exit 121Benton AR, US$2.79.9

You may want to check the Pilot Truck stop near you but it, $2,79.9 here in Benton, AR.
Doug

 

[k0ua]

It doesn't really freeze at 12F - it gets slushy. There is a heater in the tank and the DEF lines and both are heated when the truck is started. The truck runs without DEF injection in the exhaust until the DEF is liquid and will flow through the DEF lines. My understanding, from talking with a Ford tech, is that it takes about 10-15 minutes after the truck is started to get DEF liquid at 0F. I've had no trouble with my 2011 F350 in the 2-1/2 years I've owned it.

OK, so if if understand you correctly, the truck just lets the DEF go ahead and freeze when the temp gets low enough, and does not try to heat the fluid while the truck is not running, but once the truck is started it then heats the fluid and will then start injecting when it is a liquid. I guess the tank and lines will not split when the fluid freezes. OK That makes more sense. Thanks.

James K0UA