[TDIwyse]

Originally Posted by Puerto Rican 335d

I thought we could not use BIODIESEL in our engines so I read.

If I did a lot of city driving, I'd try to stay below 5% due to oil dilution risks. But with my particular driving cycle the car is able to do a complete regen on my normal commute. For instance this morning my car was at the 400 ml point since its last regen and like clockwork it did another regen. Attached some screen shots I took of my Torque App gauge cluster. The first one is mid regen cycle. Once I get into town, if it's not complete, the stop lights/idling really messes with things as it can't maintain the proper temp in the DPF. So the regen cycle would take a lot longer, and oil dilution risks would increase.

The second one is just after the regen is over and the DPF temps start coming down, and the EGR/Throttle behavior returns to "normal".

The third one is yesterday after a 3rd gear full fueling run. Notice how much hotter the EGT's (the red dot shows the max recorded ~ 850F) are during regens than during a full fuel run (although during a 1/4 mile pull I see EGT's closer to regen temps).

[floydarogers]

Thank you so much (I'm not usually so effusive, forgive me ) for posting these plots. Thanks for all the great posts.

[TDIwyse]

You're welcome.

[TDIwyse]

This is BT data during a regen from awhile back (has a lot more detail than the Torque OBD can access). It shows the post injection events and how they're used to control the DPF regen. Logging starts before the regen starts and continues until awhile after it has finished (regen finishes when the post injection events go to 0). Also showing the DPF soot and ash loading over the same time span. Kinda neat to see the Soot mass decrease as its burned off...

[Ron1n]

Originally Posted by floydarogers

I don't understand this: DPF is upstream of DEF injection and I can't see much correlation, other than the fact that the DEF injector is at the end of the DPF/CAT.

I also don't understand your "don't have". All three big trucks and the new Jeep have DEF. Not sure about the new GM small car...

You're right. It's injected just above the flex that connects to the midpipe. you're also right that it doesn't factor into the issue I had. Not sure why I posted that. However, that doesn't change the composition of biodiesel, and it's capability of clogging the DPF (presumably, especially, if it hasn't done a regen cycle).

The more research I do, the more I'm certain the meth injection had nothing to do with the overheating. I'm even more certain considering I've run the car post sensor repair with meth running again (at a less rich mixture, mind you, for now) with no issues whatsoever, even sans SCR cat.

[Puerto Rican 335d]

I almost bought a kit from a guy here in PR for do it yourself at home thing and when I told him I had a 2011 335d, he FLATLY told me I wont sell it to you since BMW has a different configuration for BIODIESEL. He did not want to be liable for any misfotunes on my car. He has a Jetta TDi

[Mik325tds]

Originally Posted by TDIwyse

For instance this morning my car was at the 400 ml point since its last regen and like clockwork it did another regen.

TDI, what do you mean by 400 ml point? Miles or milliliter? I'd like to figure out when my next one is due.
Also, do you remember what the outside temp was during that regen?
Was your coolant temp stable at 87C / 190F? I watched a regen on the highway today and while doing 75mph the coolant went up to 91C/176F and then some traffic brought it up to 98C/208 while outside temp was 27C/80F.

What was the second tool you were using to see the soot mass?

[TDIwyse]

Originally Posted by Mik325tds

TDI, what do you mean by 400 ml point? Miles or milliliter? I'd like to figure out when my next one is due.
Also, do you remember what the outside temp was during that regen?
Was your coolant temp stable at 87C / 190F? I watched a regen on the highway today and while doing 75mph the coolant went up to 91C/176F and then some traffic brought it up to 98C/208 while outside temp was 27C/80F.

What was the second tool you were using to see the soot mass?

400 "mile" point. It was very consistent and hardly varied. On long trips without much stop/start/city it would push out to ~450 miles. But don't recall it ever going further than that. I'd reset the trip odometer after each regen and watch the miles until the next one occurred.

I don't recall the outside temp for the images above. But I do recall in the hot summer months the coolant would rise to ~195-200F under certain conditions.

The 2nd tool was the Bavarian Technic product. It gives way more detailed data than the Torque app, but is more fussing around to setup and use.

[Mik325tds]

Thanks TDI. I figured you meant miles, but with the others seeing regens anywhere from 250 miles on, I was hoping you have found another way of predicting a regen.
Bavarian Technic seems to be a good product. Probably much nicer to use than the original BMW tools GT1, Rheingold, INPA. If I want to do tracing like that, I have to hook into the CAN directly and use CANoe.

[32valves]

How do you know when the car is doing a regen?

[TDIwyse]

Originally Posted by 32valves

How do you know when the car is doing a regen?

EGT (Exhaust Gas Temp) and EGR (Exhaust Gas Recirculation) behavior. As the DPF starts burning off the particulates the EGT skyrockets to the ~1150-1190F range. The EGR also shuts off (0%) during this mode. The EGT's will start coming down and EGR go back to normal operation when the regen is complete.

[kiel_dafo_kenyg_as]

Water in the DPF causes the ash residue forming some glass-like stuff which clogs the DPF.
That's why you can't clean a DPF just by flushing it with a garden hose or pressure washer

[Hoooper]

Originally Posted by whiteblue

Water in the DPF causes the ash residue forming some glass-like stuff which clogs the DPF.
That's why you can't clean a DPF just by flushing it with a garden hose or pressure washer

what information is that based on? There are thousands of reviews of people washing their DPFs with pressure washers and having success. Its probably better to do it another way, but to suggest you CANT is nonsense. For the most part, the only sites saying you cant clean a DPF with water are either environmentalist sites, DPF manufacturer sites, or DPF cleaning service sites.

How much glass do you figure I have built up in my DPF after 20k miles of w/m injection amounting to roughly 20 gallons of w/m mixture going through it?

[BB_cuda]

Originally Posted by Hoooper

what information is that based on? There are thousands of reviews of people washing their DPFs with pressure washers and having success. Its probably better to do it another way, but to suggest you CANT is nonsense. For the most part, the only sites saying you cant clean a DPF with water are either environmentalist sites, DPF manufacturer sites, or DPF cleaning service sites.

How much glass do you figure I have built up in my DPF after 20k miles of w/m injection amounting to roughly 20 gallons of w/m mixture going through it?

Just hand waving here but it would seem to me the water/meth mixture would be super heated vapor by the time it made it to the DPF after combustion. Perhaps acting a little like a steam cleaner to the exhaust tract downstream of the exhaust valves.

Was the earlier person making a point that LIQUID water would harm the DPF versus evaporated water? Meth/water inject would have to be strictly vapor going through the DPF. Temps in DPF have to be appreciably above 100°C. I'm not even certain that the water isn't disassociated into other compounds from combustion level temperatures.

Like i say, just hand wavin here.

[Hoooper]

Originally Posted by BB_cuda

Just hand waving here but it would seem to me the water/meth mixture would be super heated vapor by the time it made it to the DPF after combustion. Perhaps acting a little like a steam cleaner to the exhaust tract downstream of the exhaust valves.

Was the earlier person making a point that LIQUID water would harm the DPF versus evaporated water? Meth/water inject would have to be strictly vapor going through the DPF. Temps in DPF have to be appreciably above 100°C. I'm not even certain that the water isn't disassociated into other compounds from combustion level temperatures.

Like i say, just hand wavin here.

yeah I dont know what the theory is. All I know is that A LOT of people report success power washing their DPF when it gets clogged, and a bunch of people here and on other diesel forums run meth with a DPF and I cant think of any reported issues. When power washing the DPF, there is a lot of emphasis put on making sure you get it really well dried out, so maybe the issue comes up when you have a water logged DPF that is starting out cold and warming up slowly. I can imagine that could be an issue.

[only9balls]

TDI,
What app are you using in those images you posted?

[TDIwyse]

Originally Posted by only9balls

TDI,
What app are you using in those images you posted?

post 26 was data collected using the Bavarian Technic tool that I purchased as a group deal with the JBD 3-4 years ago. Data is saved in .csv format and imported into a spreadsheet and graphed.

post 23 has screen shots from one of my gauge displays from the android Torque app. It can also save data files to be imported into other tools, but the list of things it can see is limited compared to the Bav Tech.

[m9bm]

Why isn't the meth kit by BMS available anymore?

[Hoooper]

Probably wasnt worth the hassle. I doubt they sold many since it wasnt even advertised on the website

[only9balls]

Originally Posted by TDIwyse

post 26 was data collected using the Bavarian Technic tool that I purchased as a group deal with the JBD 3-4 years ago. Data is saved in .csv format and imported into a spreadsheet and graphed.

post 23 has screen shots from one of my gauge displays from the android Torque app. It can also save data files to be imported into other tools, but the list of things it can see is limited compared to the Bav Tech.

Thanks!

[DWR]

I've really learned a lot from this forum and thought it was time I contributed something helpful. At compression ratios and hence temperatures we have in our engines, all practical concentrations of H2O/methanol are flammable. So, any over heating of a DPF would have to do with the rate or amount of methanol injection and not the concentration itself.

[GreekboyD]

Originally Posted by DWR

I've really learned a lot from this forum and thought it was time I contributed something helpful. At compression ratios and hence temperatures we have in our engines, all practical concentrations of H2O/methanol are flammable. So, any over heating of a DPF would have to do with the rate or amount of methanol injection and not the concentration itself.

I'm sure most people running meth have removed/gutted the DPF.