regen frequency

[Newsa]

Newsa, that is generic information for any current Cummins ISB straight from the Cummins Service manual...as I stated it may not be exactly done that way on a Ram pickup but it is going to be close as Cummins manufactures the engine and the exhaust aftertreatment for the Ram.. anyway, when they refer to aftertreatment injection, what they are referring to is with a HPCR fuel system they also have the ability to inject small amounts of fuel on the exhaust stroke, which acts as an oxidizer for regeneration..

Thx for sharing

 

[AH64ID]

What year is that for? The ram trucks don't have "after injection "

Sure they do. They don't have a 7th injector, but they do inject fuel into the exhaust with the 6 main injectors. It accomplishes the same thing, and is often refereed to in a similar manner.

 

[Newsa]

Sure they do. They don't have a 7th injector, but they do inject fuel into the exhaust with the 6 main injectors. It accomplishes the same thing, and is often refereed to in a similar manner.

Yeah. I misunderstood the phrase "inject into exhaust stream". I was picturing in my mind a 7th injector in the exhaust stream.

Weird that EGT's are a concern for head gaskets and head bolts/studs, but not a concern for everything upstream of the DPF when an active regen is needed. I may never understand that concept.

I always thought that the "after injectuon" for the 4th gen was actually a late combustion cycle/combustion stroke injection rather than an exhaust cycle/exhaust stroke injection.

 

[AH64ID]

HG and stud's issues arrise from excessive cylinder pressure. A late injection event doesn't increase cylinder pressure, or even cylinder temperature much. It does increase exhaust temps, especially in the DPF, but not anywhere that melting is a concern.

Remember when we monitor EGTs the temperature is already on the way down from peak. Combustion temps peak at temperatures MUCH higher than the temp of the exhaust as it leaves the cylinder. By the time it's leaving the cylinder it's already hit peak temp and pressure and the rapid pressure drop creates a rapid temperature drop too.

To be honest I'm not sure when the post injection event occurs for regen. The post injection tables I can see in UDC pro aren't the regen timing tables.

 

[Newsa]

HG and stud's issues arrise from excessive cylinder pressure. A late injection event doesn't increase cylinder pressure, or even cylinder temperature much. It does increase exhaust temps, especially in the DPF, but not anywhere that melting is a concern.

Remember when we monitor EGTs the temperature is already on the way down from peak. Combustion temps peak at temperatures MUCH higher than the temp of the exhaust as it leaves the cylinder. By the time it's leaving the cylinder it's already hit peak temp and pressure and the rapid pressure drop creates a rapid temperature drop too.

To be honest I'm not sure when the post injection event occurs for regen. The post injection tables I can see in UDC pro aren't the regen timing tables.

Ok, Thx. I guess EGT's that people tap a sensor into the manifold for are just an indirect measure of pressure, then. Only a concern for those with a time on the engine, I'm sure.

 

[6V92TA]

Newsa, the raw fuel injected on the exhaust stroke doesn't actually ignite, but it acts as a catalyst or oxidizer. all the heat created for regen occurs as the exhaust passes over the diesel oxidation catalyst and then into the dpf proper

 

[SnoKing]

Heading toward 3 years and 40K+ and have never know when an active regen occurred. Put my hand in the door handle, climb in, push the start button and enjoy the ride. SnoKing

 

[Newsa]

Newsa, the raw fuel injected on the exhaust stroke doesn't actually ignite, but it acts as a catalyst or oxidizer. all the heat created for regen occurs as the exhaust passes over the diesel oxidation catalyst and then into the dpf proper

above, the small quantities of fuel injected into the exhaust will properly oxidize across the aftertreatment diesel oxidation catalyst, creating the additional heat required to actively regenerate the aftertreatment diesel particulate filter.

From your post in the ISB manual, the fuel DOES burn creating additional heat.

Combustion of hydrocarbons is just one type of oxidation reaction. A catalyst, on the other hand .... By definition (the catalyst in the for and the catalyst in the scr) doesn't create heat or enter into a reaction). They just provide an surface with activation conditions for the reaction to occur

 

[Cummins12V98]

Heading toward 3 years and 40K+ and have never know when an active regen occurred. Put my hand in the door handle, climb in, push the start button and enjoy the ride. SnoKing

53K and 3 years with no idea if and or when mine has done a re gen. I have to put my foot on the brake pedal before mine will start.

 

[Badunit]

My 2015 does an active regen every 24 (or so) hours of operation, which is about every 800-1000 miles. This is with a mix of highway and urban driving, minimal towing, and it doesn't matter how much of each, it is still every 24 hours. I can set the trip meter and it comes on like clockwork. 20 minutes later, it is done. I have never noticed one occur out of cycle. I monitor the DPF temperature and when it rises to 1000+ when the EGT is lower, that's when it is happening.

 

[Andrew Jahn]

My 2014 6.7 Ram has been regening every day for the past multiple months. No Codes - so the dealer says nothing is wrong. Its averaging 30 to 40 miles between regens.
I drive 20 miles to work and 20 miles home - all highway averaging 55 to 60 MPH.
When I first got the truck it wasn't like this. The MPG's have dropped from low 20's to mid 17's. Mostly due to the constant DPF regen.

I'm at a loss and with the dealer not showing anything I don't know what to do.

 

[Cummins12V98]

I would say NOT normal for your driving style! Different dealer?

 

[kthaxton]

Curious how you verify it is regening?

My normal mileage is between 15-16 mpgs.

 

[6V92TA]

My 2014 6.7 Ram has been regening every day for the past multiple months. No Codes - so the dealer says nothing is wrong. Its averaging 30 to 40 miles between regens.
I drive 20 miles to work and 20 miles home - all highway averaging 55 to 60 MPH.
When I first got the truck it wasn't like this. The MPG's have dropped from low 20's to mid 17's. Mostly due to the constant DPF regen.

I'm at a loss and with the dealer not showing anything I don't know what to do.

do youmean its flagging you witha warning ever day? how many miles are on the truck?

 

[Lynx0849]

Curious how you verify it is regening?

My normal mileage is between 15-16 mpgs.

Yes, I have added 3000 miles since I bought my 2015 but never noticed any regen messages?


Pro

 

[kthaxton]

Yes, I have added 3000 miles since I bought my 2015 but never noticed any regen messages?

I'm sorta confused....are you asking me a question?

 

[Andrew Jahn]

I have a monitor. I can see when the Soot level reaches 100% and when the computer triggers a regen. I do not get the EVIC message everyday. Its the background regen.

2014 with 79,000 miles.

 

[Lynx0849]

I'm sorta confused....are you asking me a question?

Sorry, I was agreeing with previous poster who asked how to tell when in regen.

My typing isn’t up to par this morning I guess...


Pro

 

[kthaxton]

I have a monitor. I can see when the Soot level reaches 100% and when the computer triggers a regen. I do not get the EVIC message everyday. Its the background regen.

2014 with 79,000 miles.

Yeah, somethings not right. It seems I've read in the past that there was a known issue like this and there was a flash to fix it. Might be worth calling a dealer....and/or searching this forum further.

 

[Andrew Jahn]

Yeah, somethings not right. It seems I've read in the past that there was a known issue like this and there was a flash to fix it. Might be worth calling a dealer....and/or searching this forum further.

I've had that done....