Lean burn technology at work?

shutterfly

Veteran Member
Joined
Dec 29, 2005
Location
Houston, TX
TDI
2010 JSW
For a couple of times after I shut off the engine and I can hear the radiator fans working hard with keys off the ignition. At the same time I can smell burning rubber coming from underneath the car.
Is that lean burn tech at work, when the car burns off the carbon particles?
 

fleuger99

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Nov 25, 2009
Location
MA
TDI
2012 Touareg TDI
boerssd said:
You'll find several posts and topics on that here already. That is a DPF regen that you caught in process...
Indeed it is, I smelt it just Friday after getting to work. I thought my brakes were on fire ;)
 

Pelican18TQA4

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Sep 7, 2002
Location
Philadelphia, PA
TDI
'13 Jetta Hybrid
Diesels are, by their very nature, lean burn engines. That's part of the reason that they achieve better fuel economy than a similarly-sized gas engine :)
 

UberVW_TDI

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Sep 3, 2009
Location
Austin, TX
TDI
2010 Golf Variant TDI
I wrote VW and suggested that they include a DPF regen indication light on future TDI DPF models. I've caught mine in mid regen three times now. I could of kept driving in a couple of those occurances to allow the regen to finish.
It is concerning when you first experience this....fan kicks on and the "hot" smell.
 

mysql

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Jan 19, 2010
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United States
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Jetta wagon
For some reason I thought there was a regen light on the dash. I've been looking for it but never see it.

It makes sense that they do not show it to end users though. It's an automated process and users will freak out thinking there is an issue since the dash lights usualy indicate something went wrong: check engine, check coolant, check oil, etc.
 

UberVW_TDI

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2010 Golf Variant TDI
mysql said:
For some reason I thought there was a regen light on the dash. I've been looking for it but never see it.

It makes sense that they do not show it to end users though. It's an automated process and users will freak out thinking there is an issue since the dash lights usualy indicate something went wrong: check engine, check coolant, check oil, etc.

Your right, there is a indication light for the DPF already. But it only comes on when the DPF is clogged due to constant short trip driving. The symbol looks like a DPF and is yellow. If this indication light comes on, the manual says to take the car out and drive at least 37mph for 15 minutes, and to try to keep ~ 2000 rpm to allow the car to perform a regen.

I would like an indication light that says "DPF REGEN", maybe in green? I understand what your saying about people not understanding what the symbol means, and freaking out. For me, thats one of the things I really love about VW, I enjoy more interface with my car while driving.
 
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Pelican18TQA4

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'13 Jetta Hybrid
Under normal conditions, shutting down during a regen isn't harmful. Including an idiot light to tell people that a regen is going on will only freak them out, or piss them off, or both! You don't need to keep driving around to make sure the regen finishes before you shut the engine off so why have a light that tells people that a regen is happening? Nothing changes as far as the typical driver can tell when a regen is occurring, so why notify the driver at all? Also, if you're at all mechanically-astute or "in-touch" with your car, you can tell that a regen is going on so in theory, you should be able to tell even without an idiot light :)
 

dpg

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2013 JSW TDI, 2010 JSW - retired
Pelican18TQA4 said:
Under normal conditions, shutting down during a regen isn't harmful. Including an idiot light to tell people that a regen is going on will only freak them out, or piss them off, or both! You don't need to keep driving around to make sure the regen finishes before you shut the engine off so why have a light that tells people that a regen is happening? Nothing changes as far as the typical driver can tell when a regen is occurring, so why notify the driver at all? Also, if you're at all mechanically-astute or "in-touch" with your car, you can tell that a regen is going on so in theory, you should be able to tell even without an idiot light :)

one of the times i could tell it was running was that i was in city traffic and all of a sudden i smelled that burning smell. kinda smelled like burnt clutch and rubber combined. very distinctive smell though.
 

UberVW_TDI

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2010 Golf Variant TDI
Pelican18TQA4 said:
Under normal conditions, shutting down during a regen isn't harmful. Including an idiot light to tell people that a regen is going on will only freak them out, or piss them off, or both! .....

Why do you think an indication light letting the driver know a DPF regen was in progress would "piss them off"?
 

UberVW_TDI

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2010 Golf Variant TDI
This brings up some questions about the regen....

Does the regen get triggered due to increased back pressure, or is it strictly mileage based? I'd guess back pressure.

Once the regen is started, does the regen go though a set sub-routine and regen for a specific time? Or does it regen until the back pressure is reduced down to a specific pressure?

I agree in normal conditions, cutting a regen short is not an issue. I also understand VW is trying to make the whole regen process invisible to the customer.

I would appreciate knowing when a regen is occuring. Yes, I can smell it sometimes, but it would be nice to be able to see an indication light when one notices a hot, burning smell coming from their car, instead of assuming its a regen and not a stuck rear brake or some other issue going on.
 
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dpg

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I'm thinking maybe in the MFD there could be just a ding, with the text for a min or so just as an FYI. Don't even need a light. There is a ding for temps below 40, so why not one for the regen. I can see something like that maybe
 

JSWTDI09

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Location
Las Vegas, Nevada
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2009 JSW TDI (gone but not forgotten)
There are a number of different things that can trigger a regen. Miles driven, DPF pressure differential, estimated soot load, etc. Your ECU is pretty smart and adaptable.

There are also several ways to tell if a regen is occurring. Hearing the fans, or smelling the odor are easy ones to understand. If you are paying attention, I've been told that you can also see a noticable drop in the instantanious fuel mileage, if you are paying attention (because extrra fuel is being injected on the exhaust stroke). If you have a boost gauge, this will tell you also. I've heard that the boost will go up during a regen (to compensate, so you don't notice a drop in power.

If you haven't already, you might want to read this thread. It's kinda long, but there's a lot of good info.

http://forums.tdiclub.com/showthread.php?t=266638

Have Fun!

Don
 
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jbright

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Indianapolis
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2009 Jetta DSG
The other day I noticed my rpm were higher than normal at a stoplight. I drove a few blocks to my destination and when I turned off the car, sure enough, regen.
 

JSWTDI09

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2009 JSW TDI (gone but not forgotten)
jbright said:
The other day I noticed my rpm were higher than normal at a stoplight. I drove a few blocks to my destination and when I turned off the car, sure enough, regen.
I forgot to mention that one.:rolleyes:
 

takebars

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Location
Denver
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2010 JSW DSG
I understand a lot of people disable them, but DRL has a nice green light on the dash. I really could care less either way, as I just enjoy driving my car. However, I think that the American public would be able to understand a nice green light on the dash, at least pointing them to a page in the owners manual. It would probably save countless calls to dealerships, and hundreds of threads in forums across the internet.
 

Pelican18TQA4

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'13 Jetta Hybrid
UberVW_TDI said:
Why do you think an indication light letting the driver know a DPF regen was in progress would "piss them off"?
Because there would be this light that comes on roughly every 300 miles and just when they get the owner's manual out to look it up or call the dealer to complain, the light will disappear since it's likely that it'll only take one drive to clear the DPF. Not to mention, if you do shutdown the engine during a regen, the regen does not start immediately the next time the engine is started; engine parameters have to be right before that will occur. My point is, the light would likely be coming on and off quite frequently.
 

ppcjbj

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central illinois
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2010 Sportwagen sold
I agree that it should show what is going on, my beautiful White Gold 2010 JSW with 487 miles, scared the life out of my wife, when it started the REGEN ( fans running extreme heat) , I was ready to pull it of of the garage, but I turned the car off and on and it finally cooled down, I lost sleep that night till VW opened and called the dealership...GUESS WHAT, they had no idea what caused it. Thats when I found out this great website and found out it was normal. :eek:
 

UberVW_TDI

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2010 Golf Variant TDI
Thank you ppcjbj.

More information is often better.

Dear VW,
Please add an indication light to future models to let people know when the car is doing a DPF regeneration. Your typical TDI driver can handle it. Most of your customers love the uniqueness of their VeeDubs, it won't make them mad or freak them out. In fact, it will give them a heads up that if they end up shutting down the car mid cycle, they might notice a slight burning smell and the cooling fans will kick on for 10 minutes or so.
More driver/machine interaction is a good thing. That's one of the selling points of most VW's anyway. Remember your sales line, "Drivers Wanted"? If we wanted a bland, stale, isolated driving experience we would of bought ourselves a Toyota Prius.
 

MaxHedrm

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Jul 5, 2006
Location
Dallas, Texas, USA
So that's what that was the other night. Good to know. I just thought maybe I finally managed to get it warmed up thoroughly. ;)

UberVW_TDI said:
More information is often better.

Your typical TDI driver can handle it.
The people that come to these forums are in no way typical drivers. Typical drivers (TDI or otherwise) might notice the smell, but I doubt it. & I doubt even more they would notice the fans. And what value does knowing this is going on add?
 
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