Oil Dilution From Frequent DPF Regens

whiplash willy

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I had been tracking the frequency of my DPF active regens for a couple of months. I noticed that my regens seem to happen about ever 200-300 miles. I believe that is more frequent then most.

From myturbodiesel.com's DPF Thread

The active regeneration "self clean" occurs when filter soot loading is beyond 45% or every 466-621 miles
It is my understanding that active regens cause an increase in oil dilution, due the late cycle injection, which can get absorbed by the cylinder walls.

Since I have more frequent Active Regens then the average person, should I be concerned about increased oil dilution?

To make matters worse, I am in oregon that has mandated 5% Bio in their diesel. Biodiesel has a higher flash point and contributes to a higher rate of oil dilution. Using B5 and my more frequent Active Regens, worries me a little about my oil dilution at 10,000 miles.

From the following article:
http://www.biodieselmagazine.com/articles/2290/understanding-the-post-injection-problem/

A New Understanding of Biodiesel's Dilution Effect
Volkswagen is using post-injection for regeneration and according to Stuart Johnson with the Engineering and Environmental Office of Volkswagen Group of America, the issue of oil dilution from biodiesel is a real concern for the automakers. "We can tolerate up to 50 percent fuel mix in the oil but no more," he said at the 2008 National Biodiesel Conference.

Volkswagen tests using B5 and post-injection showed 45 percent oil dilution after 10,000 miles, but surprisingly no engine damage was evident upon inspection. "Using B10 at 10,000 miles surpasses that 50 percent threshold-and that is unacceptable," Johnson said. "We want longer oil change intervals as a car company, so it's hard for us to talk about this." The implications are that increased fuel dilution due to biodiesel blends could lead to premature engine wear if oil changes are not done more often.
So 50% oil dilution will start causing premature engine wear. The standard driver using B5 will have 45% oil dilution at 10,000 miles. If my Active Regens are happening about twice as often as the standard driver, my guess is that I will have >50% oil dilution at 10,000 miles.

I currently have about 8500 miles on my TDI (CR), with its original oil, and am planning to change it at 10,000 miles. I will be sending an oil analysis to Blackstone Labs at 10,000 miles. It should be interesting to see what they find.

Also, I wounder what it is about my driving that causes such frequent Active Regens.
 

JSWTDI09

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Also, I wonder what it is about my driving that causes such frequent Active Regens.
My guess is that you will get more frequent active regens when there are not enough passive ones. Passive regens occur during extended highway driving (rpms consistently over 2000). If much of your driving is city driving and/or short trips your car will not be able to do many passive regens. Therefore, more active ones will be necessary. Also, driving style could also influence regen frequency. More soot produced would mean that the DPF will "fill up" sooner and need to be regenerated more often. There are probably many possible factors involved.

Have Fun!

Don
 

CedarPark68

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whiplash,

I like your thought process and if I were you, I would be wondering the same thing.

Why not consider to simply lower your OCI?

This board is full of the the "do what the book says / save the whales / changing your oil too soon will cause damage / Mom "Germany" knows best / this is a modern oil" crowd.

If you have concern, and based on your assessment, 'perhaps' you should, then let a UOA be your guide and decide what YOUR best course of action should be.
 

RNDDUDE

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Willy, please post your oil analysis after you get it done. I am very interested in this topic, oil dilution, also.
 

740GLE

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Another thing to worry about is, are you sure the stations cary just B5 not a blend thats rated from B5 to B20? If your running B20 and not knowing it then I'd be more concerned.

UOA is the only way to know for sure, make sure you ask them to look for Bio as well as D2 dilution.
 

whiplash willy

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Thanks guys. I think I will let the oil analysis dictate my OCIs. I will make sure to have them check for D2 and Bio dilution. I will be sure to post the results.

I don't drive freeway normally, only on the occasional road trip. Most of my driving is backroads and city, and I do hit a fair bit of traffic. Each time I take her out, I do a couple heavy throttle accelerations to 4000rpm, but other then that, my DSG likes to keep the rpms in the low 1000s for the most part.

I almost exclusively fill up at the same Shell Station, which has a B5 sticker on the pump, but no more details then that. How do I know if it is just B5, and not a B5-B20 blend? Also, even if they say it is just B5, and that is what the station put in their tanks, can't things settle, which would vary the actual percentage of bio that comes out of the pump and into your tank?
 

tdiatlast

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I would doubt the fuels would separate in the brief time it's held at the service station tank...assuming it's a high-turnover station.

I'm still getting a lot of stammering from the VW dealerships I've spoken to about B5-20, oil dilution, and VWoA's continued stance mandating <5% bio. I've not gotten a clear answer to VWoA's policy in those states that have gone to bio in excess of 5%.
 

Jack Frost

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I noticed that my regens seem to happen about ever 200-300 miles. I believe that is more frequent then most.

Also, I wounder what it is about my driving that causes such frequent Active Regens.
Your regens interval look fine to me. These cars will regen after that milage whether the DPF needs it or not. VW documentaiton states that this is about every 500 miles but others on the forum with Vagcom seem to think that it is 300 miles.

If you drive in such a way, your engine will produce a lot of soot, then the regens could be sooner. Short trips will cause more frequent regens.
 

TornadoRed

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To make matters worse, I am in oregon that has mandated 5% Bio in their diesel. Biodiesel has a higher flash point and contributes to a higher rate of oil dilution. Using B5 and my more frequent Active Regens, worries me a little about my oil dilution at 10,000 miles.
(snip)
I currently have about 8500 miles on my TDI (CR), with its original oil, and am planning to change it at 10,000 miles. I will be sending an oil analysis to Blackstone Labs at 10,000 miles. It should be interesting to see what they find.
I don't think used-oil analysis on such a new engine will tell you anything useful. But, I am curious about the testing for fuel dilution -- will it look for biodiesel or just pure petro diesel?
 

Jack Frost

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So 50% oil dilution will start causing premature engine wear. The standard driver using B5 will have 45% oil dilution at 10,000 miles. If my Active Regens are happening about twice as often as the standard driver, my guess is that I will have >50% oil dilution at 10,000 miles.
You could look at this way Whiplash. If it is true that there is 50% oil dilution, then it make sense that you would see your engine oil level about two litres too high on your dipstick. Unless of course, your engine as consumes about that much.

But since I am sure that your engine does not consume anywhere that much oil, and since I am sure your dipstick does not indicate the oil level is too high; then I would conclude that you don't have to worry about oil dilution from biodiesel.

You can drive with less worry.;)
 

heidelberger75

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I just posted my UOA from Blackstone and got 3.5% fuel dilution after about 16k miles. What does the article mean by saying 45-50% fuel dilution? Does that actually mean half of what is in the crankcase is not oil but fuel?? I would imagine that would of course be detrimental to engine life!

I use fuel that is up to 7.5% bio in Germany.

Also, that article is from 2008....
 

whiplash willy

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You could look at this way Whiplash. If it is true that there is 50% oil dilution, then it make sense that you would see your engine oil level about two litres too high on your dipstick. Unless of course, your engine as consumes about that much.

But since I am sure that your engine does not consume anywhere that much oil, and since I am sure your dipstick does not indicate the oil level is too high; then I would conclude that you don't have to worry about oil dilution from biodiesel.

You can drive with less worry.;)
I never really thought of it that way. I check my oil regularly, and the level is always the same. I would still like to get the oil analysis just because I am curious. Ive got 9200 miles now, so the oil chance/analysis isn't too far away!
 

Plus 3 Golfer

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whiplash you need to disregard what is stated in the article on VW's tests as it is heresay. Look at this study published in 2009 by NREL.

This paper assesses the oil dilution impacts on an engine operating in conjunction with a diesel particle filter (DPF), oxides of nitrogen (NOx) storage, a selective catalytic reduction (SCR) emission control system, and a 20% biodiesel (soy-derived) fuel blend. ...

For the NOx storage system (which requires a late in-cylinder fuel injection for regeneration), biodiesel oil dilution levels ranged from 5%10%. For the SCR system (which used a urea solution as a reductant and late in-cylinder fuel injection for diesel particle filter regeneration), biodiesel oil dilution ranged from <4%8%. These observations were made over typical oil drain intervals....

...the oil sample/change interval started at ~50 hours at the start of aging (approximately every 10,000 miles) and then changed to ~100 hours toward the end of aging (approximately every 20,000 miles).
 

TornadoRed

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whiplash you need to disregard what is stated in the article on VW's tests as it is heresay. Look at this study published in 2009 by NREL.
Excellent article, so thank you for linking to it.

There is much material here to discuss, but I will just mention a couple points.
1) I doubt that the usual commercial testing sites measure for fatty acid methyl ester (FAME) content in the lube oil. So the reported fuel dilution figures almost certainly understate the true level of total fuel dilution.

2) The engine used for the test was a direct-injection inline-4 diesel. The study did not mention if it was turbocharged, or if the turbo was lubricated by the engine oil, or if the turbo components were examined for wear or sludge. In fact, the article did not mention sludge at all, neither presence nor absence.

But the article mentioned that the test vehicle met Euro 4 emissions standards, so we can probably assume it was turbocharged.

3) At each age, measured in hours of operation, the biodiesel dilution percentages were 100-150% greater than the diesel dilution percentages. So if existing commercial test are not looking for FAME content, then the reported numbers greatly understate the true levels of fuel dilution.
 

Plus 3 Golfer

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Excellent article, so thank you for linking to it.

There is much material here to discuss, but I will just mention a couple points.
1) I doubt that the usual commercial testing sites measure for fatty acid methyl ester (FAME) content in the lube oil. So the reported fuel dilution figures almost certainly understate the true level of total fuel dilution.

2) The engine used for the test was a direct-injection inline-4 diesel. The study did not mention if it was turbocharged, or if the turbo was lubricated by the engine oil, or if the turbo components were examined for wear or sludge. In fact, the article did not mention sludge at all, neither presence nor absence.

But the article mentioned that the test vehicle met Euro 4 emissions standards, so we can probably assume it was turbocharged.

3) At each age, measured in hours of operation, the biodiesel dilution percentages were 100-150% greater than the diesel dilution percentages. So if existing commercial test are not looking for FAME content, then the reported numbers greatly understate the true levels of fuel dilution.
Just to make sure people reading this thread (they likely won't read the NREL report:D) understand what you point out:

1) The oil dilutions are caluculated for both the FAME content (biodiesel oil dilution) and diesel fuel oil dilution. It's likely that if whiplash sends his oil for analysis, the lab doing the analysis will not measure FAME but only diesel fuel oil dilution:

The fatty acid methyl ester (FAME) content in the vehicle’s lube oil was determined using a modified version of ASTM D7371, which covers FAME content in diesel fuel oil...

Four standard checks were performed to verify calibration from both soy- and animal-derived FAMEs. Recoveries of these checks averaged 106%. Repeatability was acceptable; each of the 19 samples was run twice, and all showed an average variation of 5%. ...

The JPI5S23 method was used to measure the petroleum diesel fuel oil dilution in each sample.
2) The specs for the engine used in the test are:
ENGINE HARDWARE  The engine used for this project in the test cell as well as in the vehicle was a 4-cylinder
2.15 L high-speed direct injection (HSDI) diesel engine. The original engine calibration complied with Euro 4 emission standards. The engine utilized a conventional high-pressure exhaust gas recirculation (EGR) loop, a second-generation common-rail fuel injection system (1600 bar maximum injection pressure, solenoid injectors) with all actuators electrically controlled.
Engine Power 113 kW at 4000 rpm
Peak Torque 360 Nm at 2000 rpm
Maximum Engine Speed 4700 rpm
Maximum BMEP 21 bar
Cylinder Arrangement 4-Cylinder Inline
Firing Order 1 – 3 – 4 – 2
Valve Train 4 Valve DOHC
Bore to Stroke Ratio 1.0034
Displacement 2.15 L
Compression Ratio 18:1
Fuel Injection System 2nd Generation Common Rail


3) Athough we don't know if the engine was turbo charged or not, after the tests the engine was run for the equivalent of 240k miles on B20 and then analyzed for excessive wear. There was no mention of sludge build up and one would assume if there was an issue with sludge using B20 it would have been mentioned.

After the completion of the durability tests for the NAC and the SCR system, the engine had undergone an accelerated aging schedule representative of twice its useful life, or approximately 240,000 miles. At the conclusion of the project, the engine was disassembled and each component was carefully analyzed. All moving parts such as bearings, pistons, and piston rings were inspected and measured. None of the components of the engine, including the injectors, showed signs of excessive wear or other signs of deterioration as a result of the extended biodiesel operation.
 
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