Particulate Filter Regen

[Applejack]

How often does your engine call for particulate filter regen during:

1) Highway speed driving

2) City driving

3) Idling

[Applejack]

How often does your engine call for particulate filter regen during:

1) Highway speed driving

2) City driving

3) Idling

[rotts4u]

I only have about 4000 miles on my 08 with a Cummins 8.3L ISC engine but so far it has not gone into REGEN ever.

[Ecker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Applejack:
How often does your engine call for particulate filter regen during:

1) Highway speed driving

2) City driving

3) Idling </div></BLOCKQUOTE>
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The question can't be answered as posed -too many variables. As noted in the message just before yours the process was described. I'll repeat it here. Note the difference between passive and active regeneration; it is doing one or the other in effect continuously.

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The DPF displayed was configured for vertical installation and was only a little larger than a conventional muffler. It has an oxycatalyst stage ahead of the monolithic particulate filter with temperature sensors at the inlet, mid-chamber and at the outlet and pressure sensors measure the pressure drop across the filter stage.
The oxycat oxidizes nitrous oxide in the engine-out exhaust to nitrogen dioxide which – if the filter matrix is at a high enough temperature – will react with the carbon to produce carbon dioxide and nitrous oxide, purging the particulate matter from the filter. This continuous purging of the carbon is passive regeneration and in many applications goes on in normal truck operation. For extreme cold or in applications where the exhaust cannot be brought to temperature, active regeneration sees a very small dose of fuel injected into the exhaust stream to heat the matrix to promote the chemical reaction that removes the carbon. .

[Spikester]

As stated above Regen cycle depends a lot of variables, so hard to put parameters on it. I have about 7000 miles on my 08 6.7L 350HP ISB and have not seen a regen cycle to date. About 98% of the miles have been @ highway speeds. Low Speeds and excessive idling, city driving increases the need for Regen.

Spike

[Tom Williams]

I see there are a few out there with the new 07 engines with the new emissions. Could you give us a short report on any issues you have had, performance, and MPG.
I have not heard anything on the new engines

[Spikester]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Could you give us a short report on any issues you have had, performance, and MPG. </div></BLOCKQUOTE>

We have the 08 6.7L 350HP, 760FtLb torque version of the Cummins ISBXT with an Allison 3000MH transmission in our 28K GVW motorhome with approx. 7000 miles on it. We are are extremely happy with its performance and economy.

Have had no drive train issues to date.

Performance is excellent, pulls all 6%, and greater, grades with cruise control set at 60MPH in the economy mode, speed will dip to about 56MPH before down shift to 5th when towing. On long grades I will manually select 5th as top gear to prevent transmission hunting between 5th & 6th cruise will then maintain 60MPH.

Average fuel mileage is 9.5MPG when towing, 10.7 with no vehicle in tow. This is in the mountainous Pacific Northwest, have not had opportunity to operate in the flat part of the country yet, but I would expect to see some MPG increase when not operating in mountainous regions of the US.

Spike

[Applejack]

My understanding is that the re-gen process takes 20- 30 minutes. What happens if the re-gen is initiated but not completed and you have reached your destination and the engine is turned off ?

[Ecker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Applejack:
My understanding is that the re-gen process takes 20- 30 minutes. What happens if the re-gen is initiated but not completed and you have reached your destination and the engine is turned off ? </div></BLOCKQUOTE>
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Your statement seems to indicate some confusion about the regeneration process. Under normal driving i.e. above ~20MPH the DPF will be continously doing what is called passive regeneration. This means that hot exhaust gases passing through the precious metal filter will convert the particulate matter (soot) to carbon dioxide and will be performed without any external input and will be going on continuously.

If one drives in low ambient temperatures or lightly loaded conditions to point where the exhaust gases never get the filter up to temperature then active regeneration is performed by injecting a very small amount of fuel into filter to burn and raise the temperature to where the normal conversion process can occur. This active process occurs automatically and may require 15-20 minutes of time. In either case the driver has nothing to do.
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There are situation in trucks and possibly buses where parked regeneration is required and a button is placed in drivers cockpit to activate.This process can take from 20-40 minutes. However, I don't believe any RV's have this option unless it might be the Prevost guys.
This process could vary from chassis builder to chassis builder so consult their manual for exact process.
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Let me make one more comment. It relates to messages talking about cleaning the DPF. There is nothing left to be cleaned from the soot burn up; it is a gas that is expelled out the tailpipe. However, any oil that leaks through the DPF will be turned to ash and need to be cleaned. One is supposed to use only CJ-4 oil in 2007+ engines since this oil is very low ash designed to minimize this problem. In any case, Federal Law requires that the DPF be able to run 150,000 miles before cleaning and Cummins has said they estimate 200,000-400,000 before cleaning is required. This cleaning must be done on specialized equipment but I don't think RVers are going to accumulate these high mileages for years if ever.

[Applejack]

Thanks Leo !

[Applejack]

On April 4th I was to take delivery of my 2008 Ellipse (400 Cummins). When doing the walk through noticed that the "check engine light" was on with the particulate filter symbol displayed. Needless to say I did not take the unit at that time.

Finally took delivery yesterday (April 26), the dealer had sent the unit to Freightliner to have the issue resolved. The freightliner invoice indicated that they had initiated a manual re-gen and cleared the error code. The dealer told me that the code was the result of excessive idleing, which he could not understand because after the motorhome was delivered from the factory to the dealer only the PDI was performed on it. I am wondering if perhaps the unit was filled with LSD at some point in the delivery from the factory to dealer.