Chrysler Diesel Exhaust Fluid System Previews NOx Reduction Solutions for 2010

DEF Display in Ram Information Display

It’s been said that heavy-duty pickup truck owners who haul and tow frequently have diesel running through their veins. They crave diesel’s high torque at low rpms and extended driving range between fill-ups. Soon, many will have to think about making pitstops for another fluid: urea.

Urea is the same organic compound found in urine, which has forced drivers (at least most drivers) to pause for bio-breaks ever since the car was invented. It turns out that urea, which is being sold under the more marketable name “diesel exhaust fluid,” is also a chemically efficient way to reduce nitrogen oxide emissions produced by diesel engines.

NOx is a major air pollutant that contributes to smog, asthma, and respiratory and heart diseases. It's a byproduct of diesel’s high combustion temperatures, which results from the high frictional heat levels created by compressing air in the cylinders to the point where it can ignite diesel fuel without using a spark. This is unlike a gas engine, which uses spark ignition to burn petrol.

Come 2010, all new diesel-powered pickups will have to meet tougher federal diesel emission standards that will reduce allowable nitrogen oxide levels by 90 percent from today and by 96 percent from 1994.

The so-called Tier 2 Bin 5 regulations also mandated the use of diesel particulate filters and ultra-low-sulfur diesel fuel to cut soot emissions by 90 percent in 2007 from 2006 levels. At 15 parts per million, ULSD contains 97 percent less sulfur than the 500 ppm low sulfur diesel it replaced.

EPA Emission Standards for Diesel

There are three ways to lower NOx emissions in diesels: The first is exhaust gas recirculation. EGR recirculates a portion of the engine's exhaust back into the engine at a lower temperature. The cooled gases have a higher heat capacity and contain less oxygen than air, lowering combustion temperatures and reducing the formation of NOx. EGR is prevalent in today’s clean diesel engines to reduce NOx, but it’s not efficient enough in current form to meet 2010 emissions levels.

Navistar is the only diesel engine manufacturer that says it will use in-cylinder EGR only to reduce NOx next year, but it will be limited to large over-the-road truck applications and not HD pickups and chassis cabs.

The second way is the use of EGR plus a special “adsorber” catalyst material to soak up and break down remaining NOx molecules before they leave the tailpipe. Chrysler is the only heavy-duty pickup manufacturer in the segment to use this approach in its Dodge Ram 2500 and 3500 trucks. The current 2007-09 6.7-liter Cummins six-cylinder diesel powertrain reached 2010 NOx emissions requirements three years early; it will carryover into 2010 and beyond without change in these models while Ford and GM are expected to update their next-generation diesel engines for 2010 using the last technology, below.

The third, and newest, approach is selective catalytic reduction using DEF. The urea-based solution (32.5 percent industrial urea and 67.5 percent deionized water) is held in a separate storage tank and injected as a fine mist into the hot exhaust gases. The heat turns the urea into ammonia that - when combined with a special catalytic converter - breaks down the NOx into harmless nitrogen gas and water vapor.

Like Ford and GM, Chrysler will use diesel exhaust fluid to scrub NOx from the exhaust but only in its new 2010 Dodge Ram 3500, 4500 and 5500 commercial Chassis Cabs.

The Dodge Ram Chassis Cabs use the same Cummins 6.7-liter diesel as the 2500 and 3500 pickups.

You might be wondering why Chrysler is using a NOx adsorber on its HD pickups and urea SCR on its Chassis Cabs. It’s because the NOx adsorber depends on rare earth metals. Until recently, the prices of these metals had been sky high. DEF is much cheaper than rhodium or palladium. The drawback against urea though is it requires periodic maintenance and driver action.

Urea SCR Process Diagram

For demonstration purposes, Chrysler had a specially labeled Ram Chassis Cab on the floor at the 2009 Work Truck Show in Chicago to show off its new urea SCR components.

“The 2010 [Ram] Chassis Cabs start with an eight-gallon tank to hold urea,” said Kevin Mets, senior development manager for Dodge trucks. “The eight gallons gives us a good range [approximately 4,000 miles] even though the entire package [DEF plus SCR hardware] weighs about 200 pounds. We don’t rob as much payload capacity as a tank that, say, has a capacity of 16 gallons.”

DEF is expected to cost about $2.75 a gallon when pumped at truck stops and other retailers, according to the North American SCR Stakeholders Group, an ad-hoc industry alliance of truck and engine manufacturers, regulatory agencies and associations, and DEF infrastructure partners and suppliers. It will be packaged in many ways including 2.5 gallon jugs, bulk storage and DEF dispensing units.

Chrysler has located the DEF-fill port on the same side of the truck as the diesel-tank door.

“We put the urea-fill neck on the same side as the fuel neck,” Mets said. “When a guy is at the fuel station, he fills up and can do the urea [simultaneously] so his time into both is the same.”

DEF Tank

DEF lines run from the DEF tank to DEF injectors that squirt the urea-water mix into the exhaust stream, behind the diesel particulate trap. There the DEF solution decomposes into ammonia, which mixes with the nitrogen oxide to break down into nitrogen and water. It also cools extremely hot gases exiting the DPF, which acts like a self-cleaning oven during its regeneration process to incinerate trapped soot to begin the soot-trapping cycle again. Coolant lines near the DEF injectors ensure they run at the optimal temperature for the ideal chemical reaction.

DEF starts to freeze around 11 degrees, so heating lines are necessary to keep the fluid warm in very cold weather.

“It kind of goes from a liquid to a slush, like Jell-O, though it would take a long time to freeze an eight-gallon tank,” Mets said.

Heating lines, which use engine coolant, run through the DEF reservoir to warm it up when sensors in the tank determine DEF temperatures are too low.

It may take a long time for the engine to warm up in very cold conditions with sufficient extra-heat capacity to warm the DEF heating lines, especially if the truck is being used over short distances or idling. In that case, combustion temps will also be lower, reducing the amount of NOx created and requiring less or no DEF to clean the exhaust. 

DEF fluid may need to be replaced in hot climates where a truck sees little to no use for extended periods. DEF slowly converts to ammonia around 120 degrees, and the process accelerates as temperatures rise.

Of key interest is what happens if the DEF tank runs dry? Chrysler says it will provide plenty of warning to drivers before the truck is prevented from restarting without a urea supply.

DEF Flow and Heater and Coolant Lines

“It’s all mileage based,” Mets said. “The [electronic vehicle information center] will show a low-urea/fill-urea warning when there’s a 1,000-mile range left to go. As the driver gets closer [to zero] then the inducement strategy kicks in.”

That inducement strategy includes more frequent use of the low-DEF warning light, chimes that provide auditory warnings and a countdown of how many miles are left until the DEF tank is empty and the truck is immobilized.

“If the countdown goes to zero, then the next stop the driver makes and turns that vehicle off, then goes to restart, he’ll get a ‘vehicle will not restart’ message,” Mets said. “There’s plenty of warning. We’ve got a 52-gallon [diesel fuel tank], which has a range of about 600 miles or less. Eventually he’s got to fill the fuel tank back up, so he has to get off the road and make that stop, and he has to do it at a fueling station that will have a urea system there. It’s all part of the strategy.”

For those thinking of ways to defeat the DEF fluid-level system, don’t. Sensors can determine the composition of the DEF added to the truck, so substitutes like pure water or (ahem) pee can’t be used. The truck will know. It will also detect if you try to mix agricultural-grade urea and demineralized water to brew a homemade batch of DEF.

One concern we had when we saw the demo setup was the placement of the DEF tank below the crew cab, where it rode next to and below the frame rails. Mets said that was the best place to put the DEF reservoir on the truck, so it was out of the way of aftermarket upfitters adding purpose-built job hardware to the trucks. He also said Chrysler engineered the tank to have minimal impact on the truck’s breakover angle for offroad use, and it’s protected off-road by the frame.

Come Jan. 1, 2010, most new diesel pickup truck buyers are going to have to go with the flow when it comes to dealing with urea for clean emissions.


Seriously!?! You wont be able to start your truck. That is a bad move in my opinion. Someone WILL find a way around this system. There should be a Emergency/limp home mode.

Or, you could just FILL THE TANK UP!

As the article says, you get plenty of warning. If your too stupid to keep the tank filled you deserve to walk.

I am sure glad I have an 06 Cummins. I willl be keeping it for a long time. Just another way for the government to get in your pocket. I pitty the Ford and Chevy pick up diesel guys.

this year epa regulation down here in mexico changed for less contaminant diesel engines for any tipe or range. urea equiped diesel engines are the worst of them all: simply they're not ergonomic or easy to use. volvo uses them and theyre having problems. Diesel fuel rises every month down here and urea is 200% more expensive. So this will fail.
Hope scorpion engine uses heat exchangers and lots of EGR system as Detroit Diesel engines uses for EPA04 and is ready for EPA10.

So, the solution to this whole urea thing is buying a well-preserved '99 Ram with Cummins and holding on to it for many years to come :-)

i wonder what effect this will have on the use of biodiesel? I know there are issues because of the DPF, but will this additional system make it even less friendly towards blends higher than B5?

Hmm DEF Delete, anyone??

LOL- DEF Delete. Gotta love the EPA...we'll protect the enviroment by adding all these emissions crap meanwhile robbing the engines of xxx amount of horsepower and causing them to burn more feul with even less mileage. EPA, Get your asses outta your heads and hands outta our pockets. Morons. This is why i love my 5.9 Cummins with straight exhaust.

Face it diesel is dead has been for years.Go back to gas less B.S.

i think this is dumb yall are messing up perfectly amazing diesels like cummins with the epa crap the diesel trucks cant breath they dont run right just costing everyone money diesels are suppose to black smoke no matter what go back to the rignal 5.9 cummins is the only way to go wast of everyones time stupid epa crap

The EPA is doing the right thing! If we don't start protecting our enviroment there will be more poisen pumped into our air causing many deaths to come. Poisening people so you can pull a 50ft trailer at 150mp come on wake up.

The system works fine in our 90 BMW X5 35d, the tailpipe is so clean your finger is clean after wiping it. The urear fill last 9-10K miles, consumption is 1.5% fuel and the dealer fills it up free the first 50K miles, and the vehicle gets 50% better mileage than the equivalent gas model (X5 4.8i).
That said, for a truck used for international travel I'd delete the EGR, DPF and SCR (urea). There are commercially available systems for 07 and later diesel pickups "for offroad and racing only" already for DPF/EGR delete which do not cause error messages, limp mode or shutdown.
Thank God I don't live in California.

From all the new Dodge Diesel truck owners I hear about their terrible fuel economy compared to their previous truck my 2003 350 dodge gets 10liter/100Km's or aproximately 25 MPG to the old imperial Gal. and unfortunately if they don't fix the milage thing I'm fixing the old truck till it dies. I would like to get a new truck after all I've bought five Cummins engines and they fixed the dodge truck up around the motor but this green agenda as I see it wrong headed less fuel burned less CO2 more fuel burned more CO2 and more cost. It's still about the money and the cost of operation fix this is all I've got to say. then I'll buy a new truck.

OK...I work in the automotive industry and most customers are telling me they are getting 25% on average less fuel economy on their trucks (Ford, Dodge and GM) with the particulate filter that is on these trucks now. Sure it helps clean up the exhaust, but now they need to burn 25% more desiel, which means the refineries need to produce 25% more diesel, which will likely mean more oil drilling rigs working, more oil-sands monster excavators digging up oil sands, more 18 wheelers delivering fuel to stations, etc. Will the pollution saved on the diesel 3/4 and one ton trucks really offset all the additional pollution from this diesel production system? Never! I agree with some of the technology coming on these trucks, like the urea injection systems to clean up the exhaust, but let's face it, they need to clean up the exhaust while still getting BETTER milage so we can burn less diesel in the first place.

The answer is HCCI. While still a high compression ratio very efficient engine cycle, and like a diesel has no throttle losses, its high excess air cooler burn produces way less NOx, and combustion is very complete. It’s said this engine cycle can achieve gas engine emissions on diesel fuel. NOx then should not be a problem. PM and NMHC should also cease to be a problem.

It’s time to get back to basics. Adding item after item in series to a diesel engine exhaust system is no answer. The engine will become a maintenance headache and emissions in the end will be worse, costs will increase, and folks will do what they are saying here, keep their old engines running as long a possible.

I believe I’ve invented the economical HCCI engineering changes (patent pending) needed to make this cycle work at full speed and loads with cold starts (even in 2 cycle engines). The key now is to get the engine makers to check it out. I predict they will find it is the breakthrough to HCCI success they have all been seeking. Anyway, engine makers must make HCCI work because it’s the only sensible and economic answer to emissions.

Study this cycle, it’s unique, Google it, see Wikipedia. It is in effect a gas engine converted into a high compression ignition engine without throttle losses. Because the fuel is added on the intake stroke, it has time to heat up and vaporize before combustion, thus an instant and very clean burn, and hence (since fuel is vaporized and very hot before combustion) the ability to be a really lean cooler (thus much lower NOx) burn. But making HCCI work like a regular diesel is tricky business, hence the need for the invention. Lloyd Weaver, Harpswell, ME.

Was not aware of all the listed Diesel engine problems. Was
thinking of buying a new Dodge diesel pickup for higher fuel
economy. I have had two and they were very good. Looks
like time has caught up with me. Going to keep my gasoline
powered car and save the money from buying a new truck.
Thank you for such an interesting article.

HCCI technology is very interesting, but so far it has been shown only in small cars yes? What about an engine capable of 500hp/1000tq? I've wanted Cummins to build such a motor...

This new epa and smog equipment on trucks is a waste of time and money...It ruins a perfectly good engine and also ruins the possible fuel mileage they could reach and perform without this know years ago there used to be hazes or clouds above major cities due to emissions or coal being burnt..but today there is nothing to this nature we can see just fine the emissions are at the best they have ever been and the people living in those cities and the older times lived to be as old as we live we put this garbage on vehicles they are less relible need to be serviced more frequently , bring initial costs for purchase up and for operating due to lack of fuel mileage .. but hey now you by twice the fuel so twice the money to the government hmm sounds funny.. but hey were all worried about emissions and now most are unemployed because hey lets face is industry like coal mining , wood cutting cant compete with the epa and its prices so they move overseas..its all great but when were all unemployed and cant afford anything we will have our clean emissions.. on second thought if u park a car in a garage and let it run the emissions will kill you but a diesel wont it might make u sick ,but hey you guys are the experts right..

Get used to it, folks. If you have any concerns, voice them to the US EPA... not that they really care.

BTW, if you environmental wacks out there think only the vehicle and business owners pay for this extraneous crap on their equipment, guess again. YOU are paying for it in the cost of goods you buy because business operational costs always get passed down to the consumer. Many of my fellow lefty Americans love to feel good about forcing hooey like this onto "big, bad business" but the fact remains - this kind of regulation cost jobs and raises the cost of products purchased off the shelf... not to mention that all this stuff is a big pain in the posterior and typically is riddled with problems.

The wisdom of our elected (and unelected, unaccountable, bureaucratic) officials!!

I agree that the EPA needs to take steps forcing the auto industry to lower emmisions, diesels included. However, it is rediculus to ruin the economy of what was the longer lived & more fuel efficient option for pickup truck buyers. EGR shortens engine life because exhaust soot is circulated through the engine unfiltered. DPF cuts fuel economy by 25% (pretty much the undisputed number by those that drive diesel), there goes the better fuel mileage. Now diesel owners are being faced with DEF which drastically increases the overall operationg costs of a diesel.

In summary we have taken vehicles that were good for 500,000 miles and decreased the average rebuild life to 250,000 miles courtesy of the EGR. We have taken a truck that did get 20 MPG and made it get 15, granted still a little better than the gasoline equivalent of 12 or so. Now we have to add DEF every oil change at an estimated cost of $10/gallon.

Here are a few ideas to solve these issues:
Outlaw petroleum lubricants, utilize synthetics instead as they have been proven to last for 2 to 3x as long.

Instead of futile attempts at reducing NOx, reduce fuel consumption which inturn reduces emissions overall. Lighter weight metals are rarely used in vehicles due to cost but they are available and if the industry called for it they could be manufactured for less. Aluminum bodies for example could maintain strength but cut weight in half. Aluminum vehicle frames could be engineered as well. Not to mention vehicle rust would be eliminated.

Magnesium crankshafts could reduce the rotating mass of an engine drastically reducing its fuel consumption.

Engine driven fans rob any vehicle of it's economy, electric fans are far less expensive to maintain & add 2 or so MPG.

I am all for saving the environment, but not at the expense of my wallet when there are better alternatives. Perhaps I am unique in caring about over all cost of vehicle ownership, but I dont think I'm the only one.

Miven Mayfran manufacturer a wide range of conveyors like Slat conveyors and Coolant filtration for handling metal chips generated during metal cutting operation in India. much for us Baby Boomers! Here's another reason we can't enjoy retirement. We are going to be like in the game of Monopoly...our pockets are pulled out and we are broke! It is bad enough that we are paying so much for our medical and have the donut hole to worry about now we can't even enjoy traveling without our pockets being dug into even more!

Magnesium crankshafts??????? I take it you have never seen a magnesium fire!!! NOTHING puts one of those out , that I'm aware of. It has to burn up. Probably not a "clean" burn either.

Like everyone else here I wish they had left the old engines alone, but that is not happening. My F 250 went from low 20's mpg in my '99 to low teens in my '08. I hope my 2011 will be better and reliable.

It will FREEZE below 11 degrees. I guess that never happens, right?

Even more things to go wrong with diesel trucks. I bought an 2008 Dodge 6.7 and have had nothing but trouble with soot build up. DPF, ox sensor bad, egr bad, I am going back to gas and they can keep their piss trucks!

Stop voting for Democrats period! This is the party where socialist politics live. Going green and global warming are all socialist ploys to destroy are great country. Vote for the most conservative polititians and lets turn this bullshit around!

For all the earth first greenies out there that run bio fuel to help mother earth do what she's been doing for millenia without your hemp wearin butt, think about 28 bucks a gallon for a jug of glorified pee! And for the dodge guy who thinks he's funny "I feel sorry for the ford and chevy guys out there".... Really???? Cuz for and chevy didn't make a diesel before 2010? 06 duramax blows yur cummins outta the water bud.
Earth first? Yeah we'll log and strip mine the other planets later!!!! Soon the aftermarket will work out how to eliminate the pee injector and we will be back to buiseness as usual. At almost 4 bucks a gallon and rising, figure in 15-28 bucks a gallon every oil change. More than I'll pay, think I'll just wire around it. Lol take that obama.

For all the earthy people out there i have a question has anyone honestly died from diesel motor exhaust outside of a building or garage? and really i think that it should have some kind of limp home mode. i don't know if this is the way to go with motors but i don't think it is all bad

Lots of good and dumb comments. The guys are right when saying def is causing more crap in the environment over all due to more fuel use. The epa doesn't like to look at the big picture. Def is the same bad idea as hybrid cars. The batterys made for hybrids can't be made in the usa because of the epa. So they make them over seas. Still makin a mess of the ozone (if you believe in that b.s.), then they are shipped here on huge tankers which are like running 1000 old semis for a week. Then once here, loaded on trucks and shipped all over the country. Edf is the same deal, sure it makes your truck run cleaner, but the pollution created because of makin new trucks burn the stuff far outweighs the pollution that was being put out before def came along.
Besides, the ozone has not gotten worse, the world is not warming up or cooling off. Cars and trucks have not effected our planet one single bit in a bad way. It's all a theory, never been proven. If you don't agree, try researching it rather than swallowing everything that gets shoved down your throat. Global warming isn't real. Yet billions of tax dollars get eaten up every year because of it. Open your eyes friends! Big picture! Find out for yourself! But don't be blinded by your pride. I was. Then I looked at the facts and saw how wrong I was

I work in northern Alberta, what temp does the DPF freeze. What if it freezes. I see the new ford has heater hoses running throght the tank, so you run the truck for 5 months?

The third, and newest, approach is selective catalytic reduction using DEF. The urea-based solution (32.5 percent industrial urea and

This is the biggest pile of horse$hit I've ever seen or heard of in my life. The EPA is RETARDED. If it wasn't for them, we'd be getting BETTER MILEAGE IN ALL OF OUR CARS AND TRUCKS. This is also going to drive the prices of OLDER DIESEL TRUCKS INTO OUTER SPACE.....Anyone remember what the ill-concieved "Cash-For-Clunkers" did to the USED CAR AND TRUCK MARKET???? The prices have gotten RIDICULOUS! Everytime the government sets out to "solve" some supposed problem, they end up creating a whole slew of brand new ones!

Some very interesting comments here about DEF, and whether it is actually a good thing or not. Some great points on both sides

Great overview of DEF, which is becoming more and more common as newer vehicles continue to hit the road

Does the 2007 dodge 2500 have diesel exhaust fluid?
Or is it the 2010 and newer only?
The 07-09 is it just a egr valve an stuff? I would like to know thanks

Just bought a 2012 Ram 3500 w/ the Cummings 6.7 Diesel and it does NOT yet have the DEF system. I understand that for Dodge/Ram you're safe up till the 2013 model year.
BTW...LOVE my new truck!

When making fossil fuels you don't just stop the production of diesel fuel, it comes as a product with the rest of the chemicals that are projected, don't know where to put it, I suggest in your bath, for those that don't understand, unspent fuel DIEsel, in the 2.5 micron range, settle in your lungs and are absorbed in to the blood to cause cancer, go to Google 2.5 microns and read!

Does my 09 Dodge 2500 diesel have the DEF system?

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