When a external fuel injector isn't used. The extra fuel needed for regen gets injected late in the combustion cycle to create some extra heat. Some of that late injected fuel makes its way out of the combustion chamber and into the exhaust where it then gets oxidized in the DOC i.e. creates more heat to oxidize the soot in the DPF.
My 6.7 Cummins is having a daily regen. Do I need to worry about oil dilution?
- Thread starter Redhawk454
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Diesel fuel doesn’t flash off like gasoline. If diesel fuel gets in the oil it’s in the oil.
Just my $0.02
I’d check your oil daily and watch for the level to climb.
What year 6.7L do you have? If it’s an iT4 it’s probably a bigger issue than a FT4 (DEF) unit. The DEF units use less fuel during the regeneration hence the urea.
Just my $0.02
regen process amounts to trace amounts( we are talking minuscule amounts) of fuel injected on the exhaust stroke to act as an oxidizer in the DOC.. diesel oxidation catalyst for you people in Rio Lindo.
most claims about fuel dilution in the motor oil due to regeneration are nonsense.. so drive it until you get it in the shop/.
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It’s a 2022 so final tier 4
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Diesel is harder to flash but it does still flash with prolonged high oil temps. It's an ultra light oil. If most pcmo's average a noack of 10-13% i could only imagine what diesel would be.
That's because people have no idea how it works.
The regen increases the RPM, but they don't inject "extra" fuel to make more heat. Unburnt diesel, even gasoline creates a ton of soot. That would be quite stupid during a regen cycle.
Any extra diesel injected has to make it directly to the exhaust and burn there, to raise the DPF temperature. So if there is no extra injector at the DPF, that fuel is injected late in the exhaust cycle and pushed out by the pistons into the exhaust system.
Regens don't cause fuel dilution, stuck or dirty injectors do.
actually, what you are referring too sounds like a stationary or parked regen and if you have been around this stuff long enough, you might have seen a diesel engine with an extra injector in the exhaust stream.. Some ISM did it that way..
but I digress, there are 2 other types of regeneration, both which occur while driving.
passive regen
and active regen.
Stationary or parked or forced regeneration is the type that you are referring too.
True, what I described mostly happens during stationary regen, however even during driving, the extra fuel cannot be added during the compression stroke because the air/fuel mixture is already at optimum so adding more fuel would result in partial combustion, which in turn creates a lot of soot. That fuel needs to skip the combustion process in order to be effective.
yeah... they can still add a bit of fuel on the exhaust stroke during an active regeneration while driving, if necessary...
I drove a school bus for a couple years after I retired from a real job,. and the one old bus I drove was an 09 with DPF only, and that bus would go thru an active regen cycle about every day and a half.. hi exhaust temp light would come one and it would take about half n hour of steady driving before it completed... I drove a newer bus with the DPF and SCr systems, it would only go thru an active regen cycle about once a week..
There is a known issue whereby non-OEM air filters cause frequent regens anmd CEL’s especially in the 2022 and 2023 models. Something to do with overly restrictive filter media. Even MOPAR and the dealers are confused on the correct part number. Bottom line, you either want the MOPAR filter without the glue strips, or a Fleetguard filter. Fleetguard AF27684 is the correct one.
In my 2010 motorhome with the ISB 6.7 (non DEF) I never know when it is regenerating. No lights tell me, cannot feel a change in the drivability or power, nothing. Since I got this one in 2020 I've put about 17K miles and never can tell when it's regenning.
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From a performance standpoint I can’t tell if it’s in regen mode. The only reason I know is because I’m proactive and cycle through my dash to check on things such as the DPF
There has been a lot of people having regen issues because of incorrect air filters. I don’t know why they are so picky about the filters but it is an issue. I run the FleetGaurd AF 27684 in my 22 2500 and it made a big difference in the way the truck runs. Mine was regening about every 375-425 miles, 10-14 engine hours. Haven’t run it enough after the filter change unloaded. I made a trip towing for about 400 miles and another 210 unloaded and the gauge is still on zero. I think some of the dpf or regen problems can be because of fuel dilution from excessive regens.
FWIW, Hotshot's Secret EDT claims to reduce DPF regens by up to 50%. Couldn't hurt to give some a try.
I have used it and it works. But I used the Extreme and it definitely makes the fuel burn cleaner and hotter.
Really the only way to know how much fuel dilution you are getting is with a UOA. I wouldn’t want to try doing 15K OCI’ with it regening every or every other day without proof of it not happening.
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Finally got my first regen since the new filter. 24 hours and 1003 miles since the last one. Lots of highway miles though.
And the DPF gauge was on zero when it regened.
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turns out my DPF junked out completely. Dealer replaced it under warranty for 3,200$
Once great engines tarnished by all this emissions crud...
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I’m getting like 13 hours between each regen on my new DPF. I don’t know if that’s normal or not. I never measured it before on the previous DPF. People say 24 hours between each regen but I’ve never seen that number and my manual doesn’t mention anything and on Cummins website they don’t publicly publish regen times other than generic 12-24 hour for some of the first generation of DPF’s.
13 hours and 500 something miles for me. In the past month i put over 2,500 miles on my 6.7 so I do a lot of highway driving with 3-4 minutes of idle for cool down when climbing the mountain.
13 hours and 500 something miles for me. In the past month i put over 2,500 miles on my 6.7 so I do a lot of highway driving with 3-4 minutes of idle for cool down when climbing the mountain.