Regeneration - Do's and Dont's?

[meerschm]

http://pics.tdiclub.com/data/517/820433_EA288.pdf

see page 42.

perhaps someone is willing to log some values, if possible,

G235 Exhaust Gas Temperature Sensor 1
G495 Exhaust Gas Temperature Sensor 3
G648 Exhaust Gas Temperature Sensor 4

as well as measured and calculated soot levels, requested regens, distance and fuel since last regen....

a session which captures a regen should be informative.

 

[Sosin]

I would not worry about it.

remember that the way the system heats up the DPF is by sending extra unburnt fuel through the exhaust valves, past the turbo, and into the cat, where it increases the temperature.

should not really increase exhaust temps in the turbo.

if VW thought you should run the engine, the engine would stay running, not just the fan!

Makes sense Mike! Thank you for the reassurance!

Ronnie

 

[atl630]

I would not worry about it.

remember that the way the system heats up the DPF is by sending extra unburnt fuel through the exhaust valves, past the turbo, and into the cat, where it increases the temperature.

should not really increase exhaust temps in the turbo.

if VW thought you should run the engine, the engine would stay running, not just the fan!

I agree that I would not worry too much about interrupting an occasional regen (I did so occasionally in my MK6). However I saw my first regen yesterday with my Scangauge II and saw high pre-turbo EGT temps when it was happening. I think I am going to follow VeeDubTDI's advice and shutoff/restart the car for a few minutes if I have to interrupt one.

 

[VeeDubTDI]

I would not worry about it.

remember that the way the system heats up the DPF is by sending extra unburnt fuel through the exhaust valves, past the turbo, and into the cat, where it increases the temperature.

should not really increase exhaust temps in the turbo.

if VW thought you should run the engine, the engine would stay running, not just the fan!

But it does increase exhaust temps at the turbo... to ~1300°F.

 

[Sosin]

But it does increase exhaust temps at the turbo... to ~1300°F.

Okay so can this damage anything then?

 

[VeeDubTDI]

Okay so can this damage anything then?

As long as the engine is running and oil is flowing through the turbocharger, no, it is well within the design range of the components. However, when you turn the engine off and the oil stops flowing, the oil in the turbo is left to cook at whatever temperature the turbo happens to be.

Over time, given enough hot shutdowns, the coked oil will build up a film on the turbo's main bearing, which can lead to reduced turbocharger life. I don't know how many of these hot shutdowns you get before the cumulative damage becomes too much (dozens/hundreds/thousands?), so my recommendation is to avoid hot shutdowns when possible to maximize the life of your turbocharger.

I monitor exhaust temps with a ScanGaugeII and let the engine idle until the pre-turbo EGT is below 450°F.

 

[Korab]

As long as the engine is running and oil is flowing through the turbocharger, no, it is well within the design range of the components. However, when you turn the engine off and the oil stops flowing, the oil in the turbo is left to cook at whatever temperature the turbo happens to be.

Over time, given enough hot shutdowns, the coked oil will build up a film on the turbo's main bearing, which can lead to reduced turbocharger life. I don't know how many of these hot shutdowns you get before the cumulative damage becomes too much (dozens/hundreds/thousands?), so my recommendation is to avoid hot shutdowns when possible to maximize the life of your turbocharger.

I monitor exhaust temps with a ScanGaugeII and let the engine idle until the pre-turbo EGT is below 450°F.

Turbo failure = big turbo conversion. I shut it off whenever I sense a regen.

 

[astarguy]

I like Korabs plan!!!

 

[Sosin]

As long as the engine is running and oil is flowing through the turbocharger, no, it is well within the design range of the components. However, when you turn the engine off and the oil stops flowing, the oil in the turbo is left to cook at whatever temperature the turbo happens to be.

Over time, given enough hot shutdowns, the coked oil will build up a film on the turbo's main bearing, which can lead to reduced turbocharger life. I don't know how many of these hot shutdowns you get before the cumulative damage becomes too much (dozens/hundreds/thousands?), so my recommendation is to avoid hot shutdowns when possible to maximize the life of your turbocharger.

I monitor exhaust temps with a ScanGaugeII and let the engine idle until the pre-turbo EGT is below 450°F.

Hi VeeDubTDI,

I dont have a ScanGuage just yet. I've been meaning to get one but haven't had time to research which one I should get for the MK7. Until I get one and learn how to read it and such.....how long does it take for the pre-turbo EGT to get below 450°F? How many minutes should I let it idle and cool down after the regen before I shut it down?

Ronnie

 

[meerschm]

But it does increase exhaust temps at the turbo... to ~1300°F.

I stand corrected on the increased exhaust temperature through the turbo during regeneration. ( I credit your observations and re-read the self study guide one more time)

I still maintain that VW engineers addressed this issue during design and development.

So it is not a bad idea to let regen finish, or stop and let the engine idle for a minute or two if you interrupt, and can stand the wait, but also not the end of the world if you cannot do so.

if the idle speed is back close to 800 rpm, and the radiator fan is not blowing, do you think this is cool enough for those who want to minimize this stress, but do not have the capability to measure exhaust temperatures?

 

[meerschm]

Still seems like a good idea if someone can log some data against the new engine and exhaust system.

 

[VeeDubTDI]

Hi VeeDubTDI,
I dont have a ScanGuage just yet. I've been meaning to get one but haven't had time to research which one I should get for the MK7. Until I get one and learn how to read it and such.....how long does it take for the pre-turbo EGT to get below 450°F? How many minutes should I let it idle and cool down after the regen before I shut it down?
Ronnie

60 seconds is usually sufficient unless the engine is in regen, in which case it could take 5-10 minutes or more.

ScanGaugeII will work with your Mk7 just fine. http://www.scangauge.com/products/scangaugeii/

 

[Sosin]

60 seconds is usually sufficient unless the engine is in regen, in which case it could take 5-10 minutes or more.
ScanGaugeII will work with your Mk7 just fine. http://www.scangauge.com/products/scangaugeii/

Awesome! Thanks for the help again VeeDubTDI!

Ronnie

 

[whizznbyu]

I am having a difficult time understanding regen & the fan staying on after the engine is turned off, the electric coolant pump continuing to circulate coolant to vital parts, etc. Regarding the turbocharger: once the engine is turned off during a regen, oil stops circulating. Does the coolant cool the oil in the turbocharger? Is this enough to prevent "coking"? Ideally, a car should ldle until the regen is complete however this is not convenient in many cases. If there is cause for concern about shortened turbo life due to "coking", is it sensible to shorten the OCI?

 

[Lightflyer1]

No do not shorten the oil change interval. If you have real concern about coking, don't interrupt it. If it is happening that often for you, you really should take an active role in monitoring them and taking the appropriate action. It only takes minutes (5 or 10 maybe) to cool. I watch VAGDPF and if I am starting a regen or one is in progress I will keep driving until finished. But I always leave early as I hate being late for anything. The few extra minutes don't matter for me.

 

[rocky raccoon]

Has anyone rigged a telltale lamp for regeneration? I would like a positive indicator.

 

[Lightflyer1]

The VAGDPF app is pretty good. Cheap app/BT dongle/android phone/tablet and good to go. I use one of my old android phones for dedicated car use. VAGDPF and Torque app run on it. Torque can even be set to sound alarms when temps exceed a threshhold.

 

[rocky raccoon]

Sounds o.k. flyer but I just want something to tell me a regen is in progress while driving down the road.

 

[bigb]

Has anyone rigged a telltale lamp for regeneration? I would like a positive indicator.

P3 Vent Gauge (VW) (Mk5- Mk7)

Kerma TDI features p3 gauges multiple oprions multiple prices.

kermatdi.com

If you are cash rich this is an easy option, although you will know when a regen is happening by watching EGTs you won't get any specifics like you will with the Smartphone apps mentioned above, and you may see regen temps displayed under heavy load (like mountain grades) even though a regen may not actually be in progress, you'd have a small learning curve there....The easy part is you don't have to set up your phone app every time. The phone apps are not really a hindrance to me as I use my trip odometer to know when a regen is approaching and open the Smartphone app only when I know one is close.
(note: the above linked gauge, set up for OBD which is necessary for EGT, is close to $400. The base price of $229 only includes boost)

 

[Lightflyer1]

There is no cheap "red light on" solution for what you want. You must tap into the computer to get regen info.

Sounds o.k. flyer but I just want something to tell me a regen is in progress while driving down the road.

I told you of the only thing I have ever heard of or read about here. If you have an android phone $20 +/- should get you what you want. There is no red light on when regens are happening installed or available. All of that info is in the computer. Temps alone will not tell you what you want necessarily. To get what you want you have to go to the computer.

 

[rocky raccoon]

Thank you both.

 

[Lightflyer1]

There is some electronic gizmo that gives you some of this info right in your MFD display in the dash. I can't remember the name now. Posted about here though. Fairly expensive and somewhat dependent on what car you have as to whether it works right or not. But it should be able to do what you are asking without any additional phones or anything.

Here is the in dash thing.

Polar FIS PF04, updated hardware

https://mailchi.mp/auto-polar/pf04-polarfis-mk568p-new-hardware-revision-1793369?e=0f68bb5f50 looks like this will be the solution for MQB cars. (including the MK VII)

forums.tdiclub.com

PolarFIS - AutoPolar

www.autopolar.net

 

[rocky raccoon]

All excellent answers Troopers but Too Much Information. I don't want to be distracted while driving by a display I must manipulate. I would like to just rig an LED that alerts me to regeneration in progress. There must be some point in this overcomplicated system that can be accessed.

Thanks anyway.

 

[Lightflyer1]

Good luck with that! Post what you eventually end up with.