DoctorDawg
Veteran Member
Here ya go, Pilgrim: Long-term DPF data projectJSWTDI09 said:I eagerly await your next thread with even more information.
Here ya go, Pilgrim: Long-term DPF data projectJSWTDI09 said:I eagerly await your next thread with even more information.
I don't think that the regen occurs at 300 miles exactly. More likely that it might start somewhere in those 100 miles and you won't even notice it.sowegatdi said:Whoa!! You guys are waaaaay ahead of me on this. I was getting concerned because we had had two or three regens that just happened to be occurring when the vehicle was being pulled into the garage. So, you're telling me that if the car is driven close to 100 miles per day, and a regen occurs when the vehicle is put into the garage, there is a good chance that on the third day after that, another regen will occur in the garage. So don't worry about it, huh?
Well, I would definitely say "don't worry about it". If yer DPF light doesn't come on, yer golden (and if it does, you just need to go for a 15 minute highway drive). As to the specific scenario you pose, I really wouldn't hazard a guess. Too many factors. Trust the ECU to do the right thing, and don't let a few interrupted regens freak you out.sowegatdi said:Whoa!! You guys are waaaaay ahead of me on this. I was getting concerned because we had had two or three regens that just happened to be occurring when the vehicle was being pulled into the garage. So, you're telling me that if the car is driven close to 100 miles per day, and a regen occurs when the vehicle is put into the garage, there is a good chance that on the third day after that, another regen will occur in the garage. So don't worry about it, huh?
I don't know about ScanGauge, but it is possible with Vag-Com (VCDS). Read this thread:Dagw00d said:Have not seen this mentioned yet in this thread...
Has anyone used the "ScanGauge" to monitor Differential pressure or other to indicate an active or imminent Regen?
Does anyone know what parameters are needed to program the scangauge to read any of this?
Unless you have a manual transmission.Dieselfitter said:Yes, idle goes up, but you can't detect that at highway speeds.
I've never noticed that. I've never noticed the ECU increasing rpm for any additional load like a/c, fans, etc. Why would idle rpm need to increase during a regen?pleopard said:Idle rpm also increases by about 150rpm.
Why would instantaneous MPG go up??? Your using more fuel during an active regen not less.Dieselfitter said:I found a way of telling if your car is in a Re-Gen!
- Your Engine temp goes up to around 205F
- Your Instantaneous MPG goes up about 5MPG's.
As I understand it, the idle rpm goes up during a regen to increase exhaust gas temperature. EGT must be high enough to get the regen process started (and perhaps to keep it going). Therefore increasing the idle and perhaps closing the exhaust flap is all about raising the EGT to the required level.Plus 3 Golfer said:I've never noticed that. I've never noticed the ECU increasing rpm for any additional load like a/c, fans, etc. Why would idle rpm need to increase during a regen?
I don't know it to be 100% fact, but I believe the exhaust flap is for EGR purposes and does not affect the regen process.JSWTDI09 said:As I understand it, the idle rpm goes up during a regen to increase exhaust gas temperature. EGT must be high enough to get the regen process started (and perhaps to keep it going). Therefore increasing the idle and perhaps closing the exhaust flap is all about raising the EGT to the required level.
As for your thoughts on mileage - I agree completely. It goes down, not up.
Have Fun!
Don
You could quite easily be correct. That's why I included the word "perhaps". I am certainly no expert on these things. I do, however, believe that the increased idle speed is to raise EGTs for regen.Pelican18TQA4 said:I don't know it to be 100% fact, but I believe the exhaust flap is for EGR purposes and does not affect the regen process.
ECM J623 has five ways to increase the exhaust gas temperature for active regeneration.
1. Regulate intake air – MAP sensor regulates Throttle Valve Control Module and Exhaust Valve Control Module to increase/decrease free air and stoichiometric control.
2. Shut off EGR to increase combustion temperature and increase free oxygen in combustion chamber.
3. Delay Main Injection and initiate early Secondary Injection.
4. Initiate late Secondary Injection to create Hydrocarbon vapor in cylinder and push to exhaust.
(Injection Quantity Calculated by EGT sensor signal from between DOC and DPF.)
5. Hydrocarbons are ignited in the DOC raising EGT to degrees 650 C in the DPF.
Yup, even my analog boost gauge shows about 1 psi of boost at idle during an active regen.Diesel Fuel said:I could have sworn I saw on my scan gauge using x-gauge mode a reading of 1.2PSI of boost at idle during my last REGEN.
I usually see practically 0 at normal idle.
Anyone else noticed boost levels at idle like this?
I'm certainly not an expert in regeneration (nor much else) but I would expect boost to go up because air is needed not only for normal combustion but also for for active DPF regeneration (point 1 above in the quote on regulating air).Diesel Fuel said:I could have sworn I saw on my scan gauge using x-gauge mode a reading of 1.2PSI of boost at idle during my last REGEN.
I usually see practically 0 at normal idle.
Anyone else noticed boost levels at idle like this?
Passive regen requires 300 to 450C. Active regen temps are 550C to 650C. CR TDIs use secondary injection after the main injection to raise temps in the DPF. Here's a link to read.Westro said:I've always wondered what temps are required at the DPF to support regen? ie that temps do the heads/valves see? Or do the new Common Rail Motors have a 5th injector in the exhaust?
I'm concerned what all that extra heat maybe doing to the longevity of the top end of the motor and more importantly the turbo.
Hi Doc,DoctorDawg said:One minor correction to a very good post:
Due to weather and driving conditions this winter I have now had four (4) interrupted regens in a row. In none of these cases has a regen started again the next time I fired up the car (despite the fact that the next start-up was always a highway drive, with EGTs and revs that would otherwise have permitted a regen)...rather, in every case the ECU simply waited the standard 300 miles to initiate the next regen (I know this for sure because I'm collecting DPF data daily in preparation for a new thread on this topic...coming soon). I won't say that it would never be the case that the ECU wouldn't re-initiate a regen after the next start...maybe if some parameter such as DPF pressure differential or carbon load was way too high this might happen. But, based on my experience, it is not usually the case that an interrupted regen will be followed by another attempt when you next start the car.
I imagine that even if the block is aluminum it would have cylinder sleeves from a harder metal. Aluminum is too soft to handle the constant friction of the rings.TDIMeister said:There have never been any Volkswagen cylinder head made for passenger car engines made from cast iron. All are made from aluminum alloy.