Passat Active Regens - How Often [Fans run after shutdown]

Niner said:

I was kind of worried about that furnace blast hitting my front tire on my mountain bike, it was right in line.

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Niner, any long time rider knows you NEVER put the tires near the exhaust pipes or exhaust stream.

Besides, I thought you were at least my age and you are still riding? LOL! You know how the yung'uns on here think. I am still Mountain snowmobiling (not to be confused with trail riding by any means) so I can't really talk.

Caught a regen on video a couple nights ago while getting off the highway. Let it finish up in the driveway and watched it with the iPhone (ScanGauge, Niner... Not VCDS). Played around a bit and noticed that *elevating idle speed REDUCES the EGTs*...

Video coming.

VeeDubTDI said:

Caught a regen on video a couple nights ago while getting off the highway. Let it finish up in the driveway and watched it with the iPhone (ScanGauge, Niner... Not VCDS). Played around a bit and noticed that *elevating idle speed REDUCES the EGTs*...

Video coming.

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You guys been driving too much lately.

I think I've caught a total of 4 regens on mine in 5700 miles, only two at idle and a shut off, where then fan ran afterwards. Probably my very clean driving style not sooting up the DPF? A heavy foot blows soot.

I still haven't noticed a regen at 5500 miles.

After watching this regen in action, we will not be interrupting any regens if one is happening when we're ready to park.

Reason? 1100°F EGT on shutdown = coked turbo.

VeeDubTDI said:

After watching this regen in action, we will not be interrupting any regens if one is happening when we're ready to park.

Reason? 1100°F EGT on shutdown = coked turbo.

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Holy flamethrowers, Batman, someones goose could easily be cooked at those types of turbo bearing temps. Drive the car nice, and pray for lots of passive regenerations at highway speeds, I guess.

kalalp said:

I still haven't noticed a regen at 5500 miles.

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Then you are either driving it nicely, not hammering on it, or on highway or freeway or interstate a lot of those miles, where the regens are easy and passive, not active regens at idle or in city traffic.

If an active regen happens while driving you won't notice it.

-J

1.) Driving on the highway will not do a "passive regen." The car will still do an active regen whenever it wants. EGTs on the highway are not high enough to regenerate the DPF.

2.) Driving style really doesn't amount to much in terms of how often regens happen. Drive however you want and let the car regenerate when it wants.

3.) You won't notice a regen on the highway unless you are monitoring EGT and water temperature. Totally, completely, 100% seamless.

Active regen video - http://www.youtube.com/watch?v=FQznjhZgteA

Not at all exciting, but it shows the temps throughout the process. Note how long it takes to cool back down after the regen is complete. Idle speed doesn't drop back down to normal until EGTs get around 500°F. So by the time your idle speed drops back to 750 or whatever, it's pretty safe to shut down.

What does HPR designate, and version of firmware on Scangauge that you are running? Can I get this on a 3.81. pre 2011 version of Scangauge II? Or do I need a 4.0 or later version? Can it be reflashed by ScanGauge for the newer version?

HPR = horsepower

ScanGauge can flash your current unit to the most up to date version. Their turn-around is pretty fast, too.

I'll check what version ours has later.

VeeDubTDI said:

Caught a regen on video a couple nights ago while getting off the highway. Let it finish up in the driveway and watched it with the iPhone (ScanGauge, Niner... Not VCDS). Played around a bit and noticed that *elevating idle speed REDUCES the EGTs*...

Video coming.

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That's why I said earlier that elevating the idle with the accelerator pedal was counter productive. In the vehicles that I work with the regen a stationary regen has to be started manually (via a button) and if any operator inputs are changed then the regen cancels (accel pedal, brake, clutch, parking brake, etc.). Obviously VW has made regens better integrated but the expecation of the operator is different as are the operating conditions.

Right - just as I suspected. Increasing engine speed with no additional load will likely make the regen take longer, if it's even possible due to reduced EGTs.

VeeDubTDI said:

Right - just as I suspected. Increasing engine speed with no additional load will likely make the regen take longer, if it's even possible due to reduced EGTs.

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LOL! You guys just can't let it go, huh? Makes me wonder why the lady doth protest so much.

Let it go? Merely following up with some empirical data and my own interpretation of what it means.

Another active regen going up the mountains in MD:



Note the EGT is 1041*F and the coolant temp is 215*F. Dash temp gauge still at 190*.

Keeping the coolant system in tip top shape is going to be critical on these cars.

-J

Looks like about 12 gallons burned in 509 miles... probably at or just under/over 43 MPG on that tank is my guess. What version of scan gauge firmware do you have?

Niner said:

Looks like about 12 gallons burned in 509 miles... probably at or just under/over 43 MPG on that tank is my guess. What version of scan gauge firmware do you have?

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Gonna be higher than that - I'm expecting 45 to 47 based on the MFI error I've been seeing.

Going up and down the mountains on I-68 in West Virginia, we saw EGTs going from 175 to 1150 during the regen period (due to 0 fuel injected going down hills). During the 7 minute process (I think it was extended due to being interrupted by the downhills), we went from one extreme to the other approximately 3 times.

NO - we didn't hook it up to VCDS and log it.

VeeDubTDI said:

Caught a regen on video a couple nights ago while getting off the highway. Let it finish up in the driveway and watched it with the iPhone (ScanGauge, Niner... Not VCDS). Played around a bit and noticed that *elevating idle speed REDUCES the EGTs*...

Click to expand...

as myself and others had pointed out earlier in this thread...

youre not doing it any favors by elevating the idle speed.

ValveCoverGasket said:

as myself and others had pointed out earlier in this thread...

youre not doing it any favors by elevating the idle speed.

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Right - and I was confirming that with actual data.

I'm actually really surprised that it will allow a regen to continue if the engine speed is raised at idle. I would expect that it would cancel the stationary regen at that point.

So after riding in a family members 2013 MB C200 in Heidelberg last week I switched my MFI to show l/100km values for fuel consumption (he has the economode feature that stops the engine when stopped and restarts once you release the brakes, just in time to take off), so I could compare his consumption with the 2.0 gasser with our TDIs. He was about 9.0 (25 mpg) l/100km and mine is about 6.1 (37 mpg) l/100km for reference.

Oh and they have two grades of diesel in German, regular Euro 1.50 per liter ($7.00 per gallon) and Super grade at euro 1.80 per liter ($8.37 per gallon).

Any rate while in this mode I noted a regen start as I was entering the work parking garage so I let it run.

First, it ran for 27 minutes before I ended it. I could not wait to get into work any longer. So it appears that regens can run quite a while.

Second, idle consumption is .8 l/hr.

With regen it was 1.1 l/hr. For reference turning on the A/C at idle was .4 l/hr and the regen was only .3 l/hr.

Just providing additional information.

TomB said:

...Second, idle consumption is .8 l/hr.

With regen it was 1.1 l/hr. For reference turning on the A/C at idle was .4 l/hr and the regen was only .3 l/hr...

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Am I reading this correctly? It doesn't make sense that at idle, fuel consumption is double w/o A/C...

According to the calculated horsepower display on the ScanGauge, A/C adds about 1 hp and a regen adds about 1 hp. Normal idle is somewhere around 13 hp if I remember correctly.

If you have Climatronic, A/C load is directly related to how much cooling is required to maintain cabin temperature. On a conventional climate control system, it adds heat to maintain zone temperature rather than reducing compressor output. In other words, Climatronic is more efficient than a conventional HVAC system.

...so...a/s adds 1hp, but consumes 1/2 the amount of fuel, according to TomB's post? Why am I so confused?

I think there was an error in the numbers that TomB posted. I'll have to check consumption when I get home.

I read Tom's post as Adding .4 l/hr. This would correspond to his statement that idle was .8 l/hr but with the regen it went to 1.1 l/hr resulting in the .3 l/hr he quotes at the very end of his statement.

Thus turning on the A/C at idle will result in using 1.2 l/hr.

That makes more sense! Thanks for the clarification.

So what you all are saying is to let the engine cool down after a long run? I drive 200 miles a day to work and back... in the mornings, I get no regeneration, but in the afternoons, I always get a regeneration.

Could any of you write a succinct step by step procedure for us?

Thanks!