[ajmat]

Originally Posted by saur95

There is a high possibility of the DPF getting clogged early and it is quite an expensive part. They will have to replace it under warranty too.

Bingo!

After the DSG debacle, VAG do not want to take a chance, they cannot afford to deal with various consumer cases pertaining to this. BS6 diesels are useless in Indian usage conditions where 70% of the usage is in cities.

It will be interesting to see how Mercedes fares. One possible reason is that in a longitudinal engine, the DPF unit can be fitted close to the manifold and hence will be extremely hot which helps in the filter process.

In transverse engines, read VAG, LandRover Discovery Sport/Range Rover Evoque, the DPF is located further away and in a short run/stop start situ does not reach optimum temperature hence gets clogged.

JLR had big issues with the transverse mounted Ingenium engines.

[saur95]

Originally Posted by ajmat

Bingo!

After the DSG debacle, VAG do not want to take a chance, they cannot afford to deal with various consumer cases pertaining to this. BS6 diesels are useless in India usage conditions where 70% of the usage is in cities.

It will be interesting to see how Mercedes fares. One possible reason is that in a longitudinal engine, the DPF unit can be fitted close to the manifold and hence will be extremely hot which helps in the filter process.

In transverse engines, read VAG, LandRover Discovery Sport/Range Rover Evoque, the DPF is located further away and in a short run/stop start situ does not reach optimum temperature hence gets clogged.

JLR had big issues with the transverse mounted Ingenium engines.

Absolutely. I observed that some Seltos diesel customers are already experiencing trouble with the DPF when I went through the thread. I doubt they'll be as kind to VAG considering their reputation.

Your theory on longitudinal vs transverse implementations does make sense. Thank you for pointing it out.

Also, not sure if Mercedes has an auto idle-up function to regenerate the DPF. Most implementations require the driver to press a DPF Regeneration switch when prompted (Like Toyota) or need them to drive at a higher RPM for a stipulated amount of time (Kia). Might get ignored just like the turbo-idling rule.

As for the facelifted Superb, let's hope they launch the Hybrid soon. Considering current prices and the FAME incentives, they should be able to undercut the Camry and Accord by a decent margin. It'll be perfect for chauffeur driven executives.

[gururajrv]

Originally Posted by saur95

I'm also guessing that the BS6/Euro6 VW diesels may not be suited for the BS4 fuel available currently.

There is a high possibility of the DPF getting clogged early and it is quite an expensive part. They will have to replace it under warranty too.

I'm sure it will require a lot of testing and changes to make a BS6 vehicle suited for BS4 fuels which may not pay off considering their volumes. Better to wait it out perhaps?

Exactly. I read somewhere Seltos folks are already facing check engine light due to clogged DPF (correct me if I’m mistaken) as Seltos is having BS6 compliant engine running on BS4 fuel. Why can’t our fuel industry giants bring in BS6 fuel and sell it in few designated pumps in big cities? I know it’s a ordeal of it’s own but still when they can have octane rated fuels available in pumps, believe they can arrange for an alternative before its made available for wider masses once BS6 kicks in?

Audi made a smart move for now but is going to lose out in the long run if they don’t get their amazing diesels here.

[Hayek]

I am not that sure about whether a longitudinal engine configuration will be enough to solve the problems with Indian real world driving conditions leading to clogged DPFs.

Found a very interesting UK article on DPFs.

Key points that it makes:

1) DPFs are generally designed to burn off soot through passive regeneration - which requires driving at UK motorway speeds (60 mph) for 30-50 minutes on a regular basis. Barring some BHPians, virtually no one in India does that regularly. So Passive Regeneration will not work for most users.
2) They also use active regeneration - by injecting extra fuel to burn off the soot if the filter is 40% clogged. But even that requires a 10 minute drive at sustained speeds of more than 40 mph - once again impossible in most Indian cities for peak hour driving. If the active regeneration fails, the warning lights stay on - and this can lead to greater damage to the DPF which becomes fully clogged. And of course, the extra fuel burn galls our Kitna Deti Hai obsessed crowd.
3) Forced regeneration can be done by garages - but it is costly (GBP 100+) and not a 100% guaranteed fix
4) Some models move into limp home mode or won’t start with DPF errors
5) Poor maintenance, poor fuel quality and certain engine oils also damage DPFs. By the way, the clogged DPFs for Seltoses is probably due to urban driving cycles and not just due to BS 4 fuel.

In short, I am amazed how any manufacturer thinks that DPF equipped cars are viable in India.

The more I read on this topic, the more convinced I get that VAG and Maruti have made the right call here by abandoning diesels for the Indian market - and that other manufacturers will either face customer complaints (if they build fail safes to prevent cars with clogged DPFs from driving) or potential fines (if they let customers ignore DPF failures and keep polluting).

[StarrySky]

Originally Posted by Hayek

1) DPFs are generally designed to burn off soot through passive regeneration - which requires driving at UK motorway speeds (60 mph) for 30-50 minutes on a regular basis. Barring some BHPians, virtually no one in India does that regularly. So Passive Regeneration will not work for most users.
2) They also use active regeneration - by injecting extra fuel to burn off the soot if the filter is 40% clogged. But even that requires a 10 minute drive at sustained speeds of more than 40 mph - once again impossible in most Indian cities for peak hour driving. If the active regeneration fails, the warning lights stay on - and this can lead to greater damage to the DPF which becomes fully clogged. And of course, the extra fuel burn galls our Kitna Deti Hai obsessed crowd.

When I was using a diesel Octavia (1.6 TDI), I was running many short trips in terms of distance as well as time - office was only 6km away (max speed 50km/h, took me about 10mins to get to office) and nearest shopping centre less than 2km away. Especially during winter, my usage was down to 450-500km a month. With this usage pattern, I did not have any DPF issues and never saw the DPF light come on, even in winters with temperatures dropping down to -28 degree Celsius on occasion and remaining below -10 degrees Celsius for weeks at a time. I have even seen the engine temperature dropping while the car was being driven at 40km/h I guess I have to thank active regeneration for keeping the DPF working. If a regeneration is interrupted because the car is switched off, the regeneration resumes the next time the car is driven. My car also had start/stop feature which automatically gets disabled if a regeneration is going on, so stopping at a signal or being stuck in traffic will not interrupt a regeneration.

I am not sure there would be DPF issues in Indian driving conditions if active regeneration works as intended. Of course, this means FE will take a nosedive as I have also experienced.

[ajmat]

Originally Posted by StarrySky

(max speed 50km/h, took me about 10mins to get to office) and nearest shopping centre less than 2km away. Especially during winter, my usage was down to 450-500km a month. With this usage pattern,

I am not sure there would be DPF issues in Indian driving conditions if active regeneration works as intended. Of course, this means FE will take a nosedive as I have also experienced.

The problem is that urban speeds in India barely touch 20km/h. Other issue is whether drivers will heed the active regeneration norms

[AnandB]

If this is true of DPF then it is going to be a major problem here in India.

Are these issues only because of BS4 diesel or will remain with BS6 fuel as well?

[StarrySky]

Originally Posted by ajmat

The problem is that urban speeds in India barely touch 20km/h. Other issue is whether drivers will heed the active regeneration norms

How does speed influence the process in normal use? Both my old Octavia and now the Karoq manuals mention:

We encourage you to avoid constant short journeys. This supports the correct function of the particulate filter.

There is no mention of driving at any speeds in normal use. Speeds are mentioned only in connection with the DPF warning light coming on.

My understanding is that the passive regeneration process takes care of clearing the DPF, but if the regeneration is interrupted too many times (by constant short journeys) then the DPF may get clogged and the DPF light will come on - and at that point some 15-20 minutes driving at constant high speeds is needed.

As I mentioned, I was almost always doing short journeys, but still did not see the DPF light ever come on.

[ajmat]

Originally Posted by StarrySky

How does speed influence the process in normal use? Both my old Octavia and now the Karoq manuals mention:
.

Short and a lower speed mean that the engine many not reach the optimum temperature and also at such low speeds in low gear, the relative load and RPM burns more fuel and hence more particulate is emitted

[StarrySky]

Originally Posted by ajmat

Short and a lower speed mean that the engine many not reach the optimum temperature and also at such low speeds in low gear, the relative load and RPM burns more fuel and hence more particulate is emitted

Not contradicting any of this, however, I have used DPF-equipped car in the similar conditions - short trips, low speed, engine unable to reach optimum temperature - and did not face issues. The speeds may have not been as low as urban conditions in India, but on the other hand temperatures have been far lower, almost always preventing engine from reaching optimum temperature (especially in winter). The big variable I see is the fuel quality available here and in India.

Of course, if the user is not aware of the DPF and active regeneration, it could end up being an expensive repair.

[ajmat]

Originally Posted by StarrySky

Not contradicting any of this, however, I have used DPF-equipped car in the similar conditions - short trips, low speed, engine unable to reach optimum temperature - and did not face issues. The speeds may have not been as low as urban conditions in India, but on the other hand temperatures have been far lower, almost always preventing engine from reaching optimum temperature (especially in winter). The big variable I see is the fuel quality available here and in India.

Of course, if the user is not aware of the DPF and active regeneration, it could end up being an expensive repair.

Those were my theories.

As you have mentioned, there are 3 variables

1: Type of usage
2: User knowledge - regarding regeneration
3: Quality of fuel

We contradict on 1: but 2 and 3, am in agreement. VAG may not want to take the risk for 2 and 3

[d3mon]

Confirmed straight from the horse's mouth. The Superb & Kodiaq are both going to get 2.0L TSIs, while the 2.0TDI will be playing truant for some time post BS6.

https://www.autocarindia.com/car-new...-engine-415134

Some quotes:

“We will have a very strong petrol engine for the Kodiaq. For someone who thought the 150hp diesel was slightly underpowered, we need to have a strong petrol coming in.”
“Now is a great time to buy diesel cars, particularly from Skoda, because when it comes to BS6, there will be a period of time that we don’t have a diesel offering in the market,”

[volkman10]

Skoda Superb on tests, no diesels as of now from the group.

the facelifted Skoda Superb will come with a powerful 2.0-litre TSI engine that’ll replace the existing 1.8-litre TSI and 2.0-litre TDI engine. Even Audi India has reported that it will launch petrol and electric models in the country in the BS6 era.

Link

[jailbird_fynix]

Skoda Superb facelift with 2.0 TSI India launch in May 2020

The same engine will be introduced the Kodiaq later in 2020.

ACI

[itwasntme]

Not easy to find a solid in-depth review of the new Superb with the 190 bhp 2.0 TSI. Please post here if anyone finds it.