Jump to content

Diesel Regeneration


Recommended Posts

We will be looking at trucks within the next year or so. I'm thinking of moving up to a 3/4 ton truck for better for capacity. I started another thread with questions on the 6.0, but have a diesel question here.

 

With the new emissions equipment on the diesel trucks I am wondering if they would even be feasible for my style of use. We tow approx. 25% of the time. But the other 75% of the time the truck is used more or less as a daily driver.

 

I've read that in order for regeneration to occur properly the truck needs to be driven at highway speeds in order to get the operating temps up. One comment mentioned needing to run 40 miles or so a couple of times a week in order for things to work as designed.

 

My normal use might not see 40 mile trips for a couple of months at a time. When I tow, it tends to be long distances. And we do take long trips 5 or 6 times each year. But when I'm at home my average trip is 10 miles round trip to town and back. It's not that often that I run more than 20-25 miles before stopping. Buti drive it pretty much daily, and might easily put on 2-3,000 miles of shorter trips before hitting the road again.

 

Will using a truck the way I have been cause problems down the road with the regeneration systems? From what I've read, repairs can be extremely expensive.

I sure don't want to have to go drive around for an hour a couple of times a week just to work through regeneration cycles.

Link to comment
Share on other sites

If everything emission wise is working properly the new diesel 2011+ will run up to 750 miles between DPF cleanout mode. During mode exhaust temps top 1250 degrees. I say that last about 20-25 minutes. I say its better once you know the truck is in regeneration to drive until it complete than to shut off while in mode.

 

The problem is GM has put no stock indicator inside the truck to know when the truck is doing this. An aftermarket Reader helps greatly to understand what is going on with these newer diesel. I have an Edge Insight CTS I use.

Link to comment
Share on other sites

So there is no way with factory equipment to know that is in regen? What you are saying about driving it until it finishes the cycle makes sense to me, but if GM doesn't put an indicator in the truck they must not think it is very important?

If it needed to happen once every 750 miles I suppose it wouldn't be the worse thing in the world, But I just know it would always happen at an inopportune time when I don't want to take the additional time to drive around for an extra half hour. Is that really what all owners of the newer diesels do?

Is there a way to manually put it into regen at a time when it is convenient?

 

I recently bought a used tractor instead of a new one primarily so that I could avoid the new regenerating exhaust systems on the new tractors. The requirements are brand new on tractors, and I didn't like the idea of testing new technology for them. I guess I was hoping that the diesel truck requirements have been in place long enough to have the bugs worked out.

Edited by Whip
Link to comment
Share on other sites

Length between regen intervals will eventually shorten. And I believe the best way to prolong this is drive the truck until the process is complete. If shut off in regen and the truck cools down. That means after start up the truck exhaust has to go back up to 1250 degrees and continue the process. Most people I think don't even pay attention to the the process. Not really a way to put it in regen manually.

 

Only way to tell without reader is smell of exhaust is different, and slightly different engine tone.

  • Like 1
Link to comment
Share on other sites

You bet the smell of the exhaust is different. Some of the nastiest stuff. I frequently deal with diesel doing regens running up and down the highway every week. A daily occurrence of having to smell that rot coming out of them. It is really a PITA to be on a hard pull on a hill and have the semi truck in front of me go into regen and I have to live in that crap for a few minutes. I even have upgraded, charcoal activated cab filters on my semi truck and that smell still makes it thru. One of the reasons I have a pre-emission motor in my 2013 semi truck.

 

Can't speak to the Dmax version, but I have talked with farmers around me that have Dodge and Ford diesels that have stated than once it hits regen, the ECM keeps the truck running until completed. One of these guys has experienced a few times where he got to the house and had to wait for the regen to finish before he could shut down. 10-15 minutes in most situations. What a waste of fuel. And it supposedly leads to cleaner air.

Edited by Cowpie
Link to comment
Share on other sites

I'll reply later

Its later now!!! I have an Edge CTS Insight to watch mine and the only thing that I have noticed about it if I am doing in town driving during a regen that it only goes down to below 10 Grams of soot, if I am running down the highway at any speed it will go all the way down to 0-1 before it ends. I have been tracking my regens for about 2 years now, looking at starting mileage, ending mileage, starting soot, ending soot, hour meter at start and at finish and just started sometime ago doing DIC mileage at start and finish. I have built a Excel spread sheet and tried to share it here but it gets junked up when I post it. My 11 has 83,000 miles on it now and it has had some long runs but 75% of it has been to work and back a total of 20 miles round trip. :jester:

Sent from my iPhone using Tapatalk

Edited by doverarjim
Link to comment
Share on other sites

GM intended that the regen process not be noticed by the operator, hence no indicator.

 

The exhaust tone is slightly different. Idle speed will be slightly higher.

 

Regen can be interupted on a dmax. Mine used primarily as a daily driver with 4 to 15 miles trips. Often the truck would be in regen for several trips, and sometimes over more than one day.

 

If the engine is unable to complete the regen after sufficient number of tries, it will put out a message to 'continue driving'. About 100,000 miles of dpf equipped dmax driving and I've never had the message come up. (I believe that the decision to put out the 'continue driving' message is actually based the calculated soot level continuing to rise when it has been trying to regen).

 

Life became simpler once I learned to just ignore the regen's and let the truck take care of itself.

 

No smoke, no diesel exhaust smell and I was happy with the fuel economy.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Each setup is different, but DPF filters do need to be removed on a maintenance interval and have a thorough cleaning thru a machine that does this. It is a good idea if folks check the maintenance schedule and see when GM suggests this be done. Unless GM is just going on the idea of do nothing till the DPF fails. That costs more than the cleaning method.

Edited by Cowpie
Link to comment
Share on other sites

GM doesn't have any such thing in the maintenance schedule and I haven't seen any discussion of needing one the any of the dmax forums I follow.

Edited by redwngr
Link to comment
Share on other sites

Well, I base that on dealing with myriads of commercial diesel trucks. DPF filters have a definitive life cycle. And if they are not properly maintained, the life cycle is significantly impacted. It is far cheaper to clean a DPF filter on a regular basis than replacing the entire unit. GM really is new to this whole thing. They are playing catch up on a lot of fronts when it comes to diesels and their various quirks. Not talking about the motors themselves so much as the emissions junk strapped on them.

 

If you were to follow more of the commercial articles and such, you would see why my comments were what they were. On commercial diesels, it is part of the maintenance schedule to have the DPF filter cleaned at between 100K and 150K. That is fairly large filters on 13-15L motors. The DPF on the Dmax is considerably smaller, to reflect the volume of exhaust, and there is a interval that the filter needs cleaned. If you look on youtube, you can see people having DPF filters cleaned from Pstroke and Cummins pickup motors.

 

Here is an example of DPF filter cleaning process from a pickup...

 

 

 

Now it is true, that the Dmax version is a sealed unit, but the filter can be cleaned occasionally to greatly extend full replacement. There are many shops that offer actual DPF cleaning. Not talking about a regen process, but a real cleaning of the DPF. There are even conversions that make the Dmax DPF unit a open and close serviceable unit, making it a easier process, saving thousands of dollars in DPF replacements. And those do not affect vehicle warranty in any way.

 

Of course, a total DPF/SCR delete is an option, but warranty goes bye-bye when you do that, and depending on where you live, you could incur some wrath from the government. Balance the odds and come up with your own decision on whether it is worth it or not.

 

But until it needs physical cleaning or replacement, operating the motor properly to facilitate proper regen sequences is imperative to long life of the filter. Here is a good recommendation on what to do.....

 

http://www.ehow.com/how_8561954_clean-dpf-66l-duramax.html

 

But eventually, the DPF unit will see the end of its useful life and will have to be replaced. That wallet busting ordeal can't be avoided. And GM doesn't have a schedule for DPF filter cleaning, nor have an easy open system that can be cleaned because they like making money from selling and installing new units. If I was in their shoes, I would to.

Edited by Cowpie
Link to comment
Share on other sites

  • 4 weeks later...

Don't get worried about the regens. The system is smart enough to compensate for your driving. On the highway about 30 miles will take a sytem from 45 gr of soot to 2 grams. I have done 700 + miles in one day on the highway with one regen.

Link to comment
Share on other sites

  • 1 month later...

Each setup is different, but DPF filters do need to be removed on a maintenance interval and have a thorough cleaning thru a machine that does this. It is a good idea if folks check the maintenance schedule and see when GM suggests this be done. Unless GM is just going on the idea of do nothing till the DPF fails. That costs more than the cleaning method.

GM doesn't have a dpf 'maintainance interval'.

Link to comment
Share on other sites

Yeah, that is because their methodology is use and replace. A more expensive way to do things and beneficial to them. But, that is not surprising. As opposed to a more cost effective machine cleaning of the DPF on a schedule basis, they just replace the unit when things clog up and it no longer works as it should.

Edited by Cowpie
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.