lhamblin

DEF (Diesel Exhaust Fluid)

19 posts in this topic

I am in the process of purchasing a new 2011 Motor Coach and I am having some second thoughts after reading the following article that was in the Monaco Newsletter.

http://monaco.rvnewsletters.com/the-truth-...ced-egr-726.htm

Has anyone had any experience with DEF on a new coach and have you experienced any of "Facts" that were stated in this article?

I would appreciate any first hand information that users have experienced so that I can hopefull make the decision on whether to buy a new Tiffin Allegro Bus or a Monaco Camelot.

Share this post


Link to post
Share on other sites

The only FACT in the article that I saw as incorrect was:

DEF freezes at 12O F, and storage isn’t recommended above 77O F.

Clearly, the article is slanted sharply toward their (Navistar) approach to the 2010 EPA emissions-- high amounts of EGR (Exhaust Gas Recirculation) vs use of Urea injection downstream of the engine.

Those "of an age" to remember gasoline cars in 1975 may remember there were a few holdouts on going to catalytic converters (which many felt at the time would be the death of the car business). Instead, they choose retarded timing and use high concentrations of EGR to reduce combustion temperatures. And, those manufacturers who did not go the converter route heavily advertised that fact. However, within a short time, everyone switched to converters, as the engines produced more HP, better MPG and better throttle response with the converter than retarded timing and high EGR.

Urea injection has been used on diesels in Europe for years to meet their stiffer emissions requirements.

Urea injection would NOT keep me from buying a new diesel any more than a catalytic converter kept me from buying a 1975 (and all years after that right up to today) model gasoline car.

Brett

Share this post


Link to post
Share on other sites

According to Monaco's web site, the 2011 Camelots come with

" Cummins® ISL 425 HP Engine with Allison® 3000 MH 6-Speed World Transmission and Electronic Shifter; Torque: 1,200 Ibs./ft. Max; Engine Displacement: 8.9L/538 cu. in."

Not a Navistar engine. This is the same engine that is found in the Allegro Bus.

"Cummins ISL 450 HP / 1250 Lb. Torque" according to Tiffins web site.

Note that the Tiffin version has higher HP and Torque.

This is a DEF engine! They probably put Navistar engines is some of their smaller diesel coaches, probably not in Pushers. You can get the Navistar engine in a Tiffin Breeze, if you want that engine and a small coach. See the December FMCA magazine for an article on the Tiffin Breeze. You will probably be happier with Tiffin's after the sale support than with Monaco's, based on my experience with Tiffin and what I have heard about Monaco!

Share this post


Link to post
Share on other sites

We just traded in our 2009 Tiffin Phaeton for a new 2011 Bus. The bus has the DEF technology on it. I have talked with several dealer service shop folks and they all claim they are hearing good things from people that are running them.

"For what that's worth?"

Good luck

Share this post


Link to post
Share on other sites
The only FACT in the article that I saw as incorrect was:

DEF freezes at 12O F, and storage isn’t recommended above 77O F.

Clearly, the article is slanted sharply toward their (Navistar) approach to the 2010 EPA emissions-- high amounts of EGR (Exhaust Gas Recirculation) vs use of Urea injection downstream of the engine.

Those "of an age" to remember gasoline cars in 1975 may remember there were a few holdouts on going to catalytic converters (which many felt at the time would be the death of the car business). Instead, they choose retarded timing and use high concentrations of EGR to reduce combustion temperatures. And, those manufacturers who did not go the converter route heavily advertised that fact. However, within a short time, everyone switched to converters, as the engines produced more HP, better MPG and better throttle response with the converter than retarded timing and high EGR.

Urea injection has been used on diesels in Europe for years to meet their stiffer emissions requirements.

Urea injection would NOT keep me from buying a new diesel any more than a catalytic converter kept me from buying a 1975 (and all years after that right up to today) model gasoline car.

Brett

Brett, How about a little lesson on the DEF for diesel engines. I for one don't know much about this new technology. I am sure there other in the same boat as myself.

Thanks in advance.

Share this post


Link to post
Share on other sites
Brett, How about a little lesson on the DEF for diesel engines. I for one don't know much about this new technology. I am sure there other in the same boat as myself.

Thanks in advance.

Herman,

Here is a good explanation from Cummins-- several good "clickables" on the page:

http://cumminsengines.com/sites/every/misc...ent_System.page

Here is a 2 page PDF you can download from Cummins as well:

http://cumminsengines.com/assets/pdf/4971166.pdf

Brett

Share this post


Link to post
Share on other sites

What Brett said, plus, I'm copying in something I posted on another forum just yesterday...

"I read up on the DEF vs EGR engines before we bought our new rig. The claims of higher mpg (Cummins estimates 6%) is in comparison to an engine of similar power meeting the '07 emissions requirements. The HP and torque are also increased, using the exact same engine as the pre 2010 emissions engines, as the DEF allows the electronics to be 'tweaked' without adversely affecting what's coming out the tailpipe. To get similar HP and torque from an EGR engine would require a slightly larger displacement and weight. As a practicle matter, only Monaco is building DPs with an EGR, vs DEF, engine, the Tiffin Breeze aside. I'd estimate that the new engine added, maybe, $7500 to our final purchase price, after discounts. No doubt the newer EGR (Navistar) engines cost more too, although I've never heard a number and doubt it is as much.

Cummins estimates a 2% usage rate for DEF to fuel. In my very limited experience so far, I'm running a bit under that. Once readily available, DEF will likely cost less than fuel, but certainly no more. This is more than off set by the estimated increase in fuel economy.

Oh, and the DEF engine does still have a 'regeneration' cycle. Seems about once every 1k miles on ours, but is no doubt influenced by how the rig is driven. The particle filter remains part of the system and must be purged every once in a while."

Someone, on that other forum, reported he'd seen DEF offered, at the pump, at $1.99 per gallon. I expect this will be the norm, once there is wide distribution.

Share this post


Link to post
Share on other sites

Having been employed in the trucking industry for 45 years, this sounds like the pro's and con's to the "ABS brakes, air disc brakes, auto transmissions, and electronic controled diesels. I remember having to repair the wireing harness on many ABS equipped units, because " those brakes will kill you". As we all know we have all those systems on motor coachs today and would not have them any other way. The final on this is, many trucking companies have purchased 100's of 2010 and now 2011 units with this system and it works. Don't be fear it, embrace it. PS< sorry but you don't want to know how much this system increases the price of the unit. Gary

Share this post


Link to post
Share on other sites
Herman,

Here is a good explanation from Cummins-- several good "clickables" on the page:

http://cumminsengines.com/sites/every/misc...ent_System.page

Here is a 2 page PDF you can download from Cummins as well:

http://cumminsengines.com/assets/pdf/4971166.pdf

Brett

Brett,

Thanks I have printed both and will review them tonight.

Herman

Share this post


Link to post
Share on other sites

About the only negative I've read about the DEF system is that is adds considerable weight (about 1K lbs) to the rear axle. If considering a coach with DEF, take a look at the legal NCC before buying. Know how much rear axle weight is left for your stuff.

Share this post


Link to post
Share on other sites

I've got one of the 'DEF' engines and can't imagine how it would add 1000 lbs. There's a 10 gallon DEF tank, some additional electronic gizmos and a big muffler like device, similar in size to the particulate filter. I can't say where, but I'm thinking I read somewhere it may add a couple hundred pounds.

Share this post


Link to post
Share on other sites

Hi Jay,

Newmar executives made this comment at a session held at one of their rallies. This is why all Newmar coaches at 40' now have a tag axle. The components are not over the rear axle. They hang off the coach some distance from the rear axle. This increases the load on the rear axle to be much more than the weight of the components themselves. The statement includes all the components of the DEF system.

Share this post


Link to post
Share on other sites

Monaco is using up all their existing ISL07 engines until they run out and then probably use the Navistar engines with EGR in leiu of DEF. All the ISL07 engines are rated at 425 HP and only have the particulate filter system, no DEF . The new ISL9 engines are rated at 450 HP and use DEF. I bought a new 2011 Monaco and was also told adding the DEF was a considerable cost addition and added significantly to the coach's weight.

Ed Robbins

Share this post


Link to post
Share on other sites

I really wonder if these regulation are worth while and end up with over rationalized more regulations. This could all lead to some kind of device to limit methane gas emissions from animals and humans since methane is many time more green house gas than CO2. :-)

Share this post


Link to post
Share on other sites

RVBusiness magazine had some stories about the difference between EGR and SCR on new diesel engines.

http://www.rvbusiness.com/2010/11/monaco-c...pro-scr-letter/

Pages 46 through 52 on the link below have stories written by Monaco and Freightliner describing why they support their systems:

http://www.rvbusiness.com/wp-content/uploa...ness1011_12.pdf

I think the bottom line is that there are pluses and minuses on each system. They both add some weight. One may slightly improve mileage and power but probably not enough to notice and the other doesn't require the DEF, but only time will tell what problems either one have in actual use on RVs.

Share this post


Link to post
Share on other sites

The first thing I love about the Monaco link is how the claim to be "customer focused". Aren't they the same company that recently filed Chapter 11 and left all their customers holding the bag with regard to warranty claims?

There are already a lot of intelligent and insightful replies to this original post.

As an actual owner of a DEF equipped coach, I must say that while there is some added work, I haven't found it to be more than about 5 minutes per time when I've had to deal with the DEF itself. And, that doesn't happen every time I stop for fuel. I haven't had any trouble finding DEF. I'm not too keen on paying the extra money. But, it is what it is. No matter what I do, they're going to get it all anyway.

I tell myself that some smart guy somewhere convinced everyone that the world would be a bit cleaner with this approach. And some smart sales person somewhere sold it to the government and to the industry. So, here I am. The Monaco approach is just a different way to achieve the same thing. I'm not smart enough to say which way is better or cheaper or longer lasting. But, given the way Monaco dumped on their owners in the past, I would be very reluctant to purchase one of their coaches.

I've had conversations with the Spartan folks about usage. They tell me that their equipment uses DEF at a rate of 2% of the fuel. That means for 100 gallons of fuel, I can expect to use two gallons of DEF. I have a gauge on the dash telling me how much DEF I have in the tank. I carry one extra gallon on board because I'm just a risk adverse sort of person. So, if I'm silly enough to get into the middle of the desert, I've got enough DEF to carry me as far as 50 gallons of fuel will take me. I've seen DEF from $5 per gallon at my RV dealer to $7.99 and Pilot.

As far as loss of bin space. I've had to give up about 6 inches in the rearmost bin on the passenger side. The DEF tank is five gallons and is built into the chassis behind the rear tag axle wheel with only the spout encroaching into the bin.

All things considered, I'm spending what equates to between 1.4 and 2 cents a mile (50 gal. of fuel times 7 (conservative estimate pulling a toad) mpg divided by $5 to $8). The result is a slightly cleaner environment (in theory).

One last thing about the Monaco link. They say that DEF freezes at 120 F. I believe that what they are trying to say is that DEF freezes as 12 degrees F. I would expect that the engine will warm the area above 12 degrees F relatively quickly. Maybe their writers and their proof readers were having a bad day. And following that logic, we shouldn't store DEF above 770 F. Well, that equates to 77 degrees F. We'd all better move to Canada. The inside of my coach approaches 105 degrees F when it's sitting in the sun without the AC. I would suspect that the bin areas get warmer than that. I'll have to do some research here. There are a lot of mitigating circumstances here. If I didn't know better, I would have to think that Monaco is trying to skew the truth to make their solution sound better.

Good luck with your decision making. I hope I was able to provide some answers to your thought processes.

Kevin

Share this post


Link to post
Share on other sites

All Monaco and Holiday Rambler Diesels manufactured by Navastar use the Double EGR system including the Cummins engines. I have looked at several and have confirmed this.

One of my problems I see with the DEF is storage. If a person does not use up the DEF before it spoils (within a year) the tank has to be cleaned and the old fluid removed. If the computer does not read the fluid is within tolerances than this is required.

Dosage for 2011 is a 1% rate meaning for 150 gallons of fuel you would require 1.5 gallons of DEF. In 2013 (I think) they will have to dose the system at 2% to meet the almost zero requirements of the EPA. The tanks I have seen on other brands are 15 gallons which at the 1% rate should last about 10,000 miles or so. If for some reason you don't travel this far in a year then you have the spoilage issue to deal with. Of course you can always put less in the tank but sometimes plans change and you might have a full tank.

I realize that this is a new technology, similar to what we had years ago with the catalytic converters but DEF is a PIA for an RV'er. Just another thing to have to watch, monitor and service. Rather than jump through hoops to get zero emissions out of diesel fuel why don't we go to natural gas? I guess we all know the reason for that!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now