[ambarkhan]

I spent 2 weeks with my 2020 Thar Diesel Manual in Laddakh and Zanskar. Which involved driving in very slow tracks for 2 days. For two days, we averaged about 15-20kmph. Before entering Ladakh, I was also worried, but we didn't encounter any issues. We never lugged the engine, it was always doing proper rpms for the speed.

We met a local road contractor *who sold his BS6 Scorpio in 3 months just because it didn't have the option of manual regeneration, and for his commute the DPF would clog every 3rd day. He then moved to Petrol Thar to avoid this.

[Mortis]

Would an additive like acetone added to the diesel help alleviate or delay these issues ? Acetone added to fuel makes it easier to combust and also increases the exhaust temperatures.

[ramzsys]

Originally Posted by Mortis

Would an additive like acetone added to the diesel help alleviate or delay these issues ? Acetone added to fuel makes it easier to combust and also increases the exhaust temperatures.

Dhabhar Behram's words 'Just remember - there is only one way to do any job and that is the correct way'

Which in this case is

Originally Posted by ambarkhan

We never lugged the engine, it was always doing proper rpms for the speed.

[ashis89]

Originally Posted by shancz

I think they ran out of options/time to make the diesels BS6 compatible, they made it work but with riders. Let's how the next gen diesels pan out.

These BS6 diesels and DPF technology have been used for quite some time now and was launched in India only recently. Manufacturers would have had sufficient learning time already.

Originally Posted by Big Smoke

No, what I was meaning to say is that can't we manually idle the car for 30 mins at high RPMs for the filter to de-clog? I believe that should solve the issue. It can be done in any BS6 Diesel car.

Theoretically, yes. However, depends on the ECU programming. If the logic is word for word of what's mentioned in the manual, ECU might wait for car to be in motion and maintain the RPM (to reach the temperature) before triggering the regeneration. Only someone who wrote or read the logic can confirm this.

Originally Posted by abhishek46

One thing to note, this Active Regeneration is not good for the engine, if it is performed multiple times. (As per Hyundai Diesel Owner's Manuals)
Looks like there is risk of Engine Oil Dilution, if these activities are frequently performed.

What's the link between regeneration and engine oil here?

Originally Posted by amit_purohit20

5) What about ensuring regeneration is done before entering high altitude zones? To ensure we start with a cleaner DPF thus taking more time to clog. Probably would give us a better chance of completing our journey before DPF gets clogged entirely.

In 'normal' operating conditions, DPF can get clogged in 600-1000 kms. In high altitudes, it should be sooner. A "range" of ~500 kms to complete the mountain circuit and return to plains, might be insufficient.

[shancz]

Originally Posted by ashis89

These BS6 diesels and DPF technology have been used for quite some time now and was launched in India only recently. Manufacturers would have had sufficient learning time already.

In that case then doesn't it look like the end of road for diesels going forward ?
Currently this specific use case and cars being run primarily in city are facing it but eventually won't it become a headache for everyone when stricter norms take place ?

IMO with electrics gaining popularity this might eventually limit the diesels only to long distance trucks and buses(and some niche SUVs) like it was supposed to be used.

[ashis89]

I am raising few queries, just out of curiosity and academic interests. Not intended to target anyone here.

Originally Posted by ambarkhan

We never lugged the engine, it was always doing proper rpms for the speed.

OP was driving an automatic car. Wouldn't the gearbox be selecting the correct gear on its own to prevent the engine from lugging?

Even in manual mode, I wonder if you can lug an automatic although it allows you to over-rev it.

Originally Posted by Mortis

Would an additive like acetone added to the diesel help alleviate or delay these issues ? Acetone added to fuel makes it easier to combust and also increases the exhaust temperatures.

Would be an experiment. But wouldn't the OEMs, who have spent crores and years developing this tech, have explored all options already?

Originally Posted by shancz

In that case then doesn't it look like the end of road for diesels going forward ?

IMO, yes.

Currently this specific use case and cars being run primarily in city are facing it but eventually won't it become a headache for everyone when stricter norms take place ?

IMO with electrics gaining popularity this might eventually limit the diesels only to long distance trucks and buses(and some niche SUVs) like it was supposed to be used.

Makes me wonder how these commerical vehicles have been surviving/faring so far? They cover the length and breadth of our country, across all types of terrains. Is the setup on commercial vehicles any different from the DPF + LNT/SCR?

Again, since this tech has been in use for some time now, how do vehicles fare in other countries and under similar high altitudes?

A quick Google shows DPF issues reported by many global users and across cars. And yet, OEMs think this tech has potential and developed/launched across all categories of vehicles.


Anyone having a more thorough knowledge of this tech, please chime in.

[ambarkhan]

One observation I missed to add in my previous comment.

The local taxi drivers idle their engine for very long periods. Now this in pre BS6 era might have helped to reduce the cold wear and tear.
But in BS6 era this is recipe for disaster. One might copy locals and endup in trouble

[shancz]

Originally Posted by ashis89

1. Makes me wonder how these commerical vehicles have been surviving/faring so far? Is the setup on commercial vehicles any different from the DPF + LNT/SCR?
2. Again, since this tech has been in use for some time now, how do vehicles fare in other countries and under similar high altitudes?
3. A quick Google shows DPF issues reported by many global users and across cars. And yet, OEMs think this tech has potential and developed/launched across all categories of vehicles.

Did some reading and found these informative articles : Credits to Providers
1. businessfleet
2. fullbay

1. From what I gather commercial vehicles can have all three based on requirements but nothing different and DPF is common across vehicle types.
They too face similar issues but in their use case, mainly highways and high loads it doesn't occur that often.

2. All depends on driving conditions, with smooth traffic flow and highways it won't be that big a concern.
I don't think overseas, a lot of countries have that many diesel cars in city use and BS6 level norms at the same time.

3. Based on the links above and some other resources I have read in the past I think giving up on diesels was too much of a sales hit for them so they put in whatever they had. We still bash MSIL for not having diesels in their lineup and they've lost sales due to that as well. And why would manufacturers care, this is something they can directly blame on the customer's driving style and higher maintenance bills would just be an icing on the cake for the dealers.

Coming back top OP's post,
Like mentioned by sukarsan in his post

Originally Posted by sukarsan

There is another mode called passive regeneration. This would be of academic interest wrt this thread.

and quoting the fullbay link :

Passive Regeneration
Passive regeneration happens automatically. Once the exhaust temperature reaches a certain point, for example while driving at high speeds, the built up matter in the DPF turns to ash. No active changes in engine operation are involved. Diesel trucks on a heavy duty cycle, for example climbing a lot of hills, should have no problem passively regenerating their DPF. Under these conditions, soot burns off as fast as it is generated.

This had been bugging me since in my head this made sense : hills=high load/rpms=high temperatures=soot burn=DPF clean.
But his case is the opposite leading me to think that the DPF was reaching its limit while entering the hills and couldn't sufficiently regen contributed by the auto box keeping higher gears.
But this is a big concern since there doesn't seem to be any solution for it, globally.

Regarding the contributing factors and quoting the businessfleet link :

Keep it Clean
According to Dan Whittle, service manager for Cumberland Trucks, an international dealer serving Tennessee with its headquarters in Nashville, the following issues will cause premature clogging of the DPF filter:

City driving with a light load
Stop-and-go traffic
Excessive use of engine brakes
Inappropriate engine oil type: engines using non-low ash oil meeting the API performance classification CI-4/SL will retain soot and ash prematurely
Operator error

One thing that might also be looked at is the engine oil being used but since I am not competent on on that topic will leave it to more informed BHPians and BS6 diesel owners to check on it.

[Livnletcarsliv]

Is this not a significantly huge setback for diesel cars and manufacturers?
Is this not an economic and operational impact for tour operators and drivers in these regions?

From all the discussions above, I understand that BS6 diesel cars are at high risk to drive in the Himalayas and other oxygen-deprived places. So it's better to avoid BS6 diesel cars in these regions?

What is the permanent solution for this? What do the manufacturers have to say about this? Then, what are they testing these engines in these high altitudes for?

[anshu1101]

Have any issues of DPF clogging been reported with the BS6 Jeep Compass in these high altitudes? Does it have a manual regeneration option like the Fortuner/Innova?

[padmrajravi]

We are declaring the death of diesel engines here based on the performance of a single vehicle - Mahindra Thar. We all know how initial lot of Mahindra vehicles fare. I think this is most likely a software bug. Either Thar failed to let the user know of the manual regeneration requirement or it simply failed to detect the need. It should be something easily fixable through a software upgrade. Remember Mahindra just started manufacturing Bs6 vehicles a year back, so their processes may have flaws.

Internationally DPF equipped diesel engines have been in existence for a while now and there are no such cases of complete failures in hilly regions. We are not the only ones with hills and low oxygen concentration areas. I know there is a class action against Toyota diesel DPF issues, but that is not about complete breakdowns. It is about the higher noise, smoke and odour during auto DPF regeneration. And some issues regarding too frequent auto regeneration. These were supposedly fixed with software upgrades.

Unless there are more vehicles models and manufacturers experiencing such issues in hilly regions, I won't bother too much with this. The thread title is actually misleading. Over the full course of the thread, there are only instances mentioned - A Thar and a Scorpio. The title should read 'Mahindra BS6 diesels not performing in hilly regions'. Writing off all BS6 diesel engines based on evidence of two Mahindra diesel BS6 failures does not seem logical.

[shancz]

Originally Posted by padmrajravi

We are declaring the death of diesel engines here based on the performance of a single vehicle - Mahindra Thar.
Over the full course of the thread, there are only instances mentioned - A Thar and a Scorpio.

The OP's vehicle is a Hyundai Tucson so this assumption of yours is incorrect. Not to forget the issues being already faced by Ford and some Kia owners reported elsewhere.
We are not declaring deaths of anything, just curious about how this entire system(DPF-LNT-SCR) works. Reading up on it, going by common sense and logic it doesn't look too great.
Would be great if someone better informed can shed some light onto this.

Originally Posted by padmrajravi

Internationally DPF equipped diesel engines have been in existence for a while now and there are no such cases of complete failures in hilly regions.

I tried searching online and found some links from the people who would face it the most : truckers(international too), please see post #38(2 posts above yours).

[padmrajravi]

Originally Posted by shancz

The OP's vehicle is a Hyundai Tucson so this assumption of yours is incorrect. Not to forget the issues being already faced by Ford and some Kia owners reported elsewhere.

My bad, I was counting only the breakdowns that owners faced. I think a DPF warning light in hills, while concerning, is still not as bad as what the Thar faced. I think that is something Mahindra specific.

Originally Posted by shancz

I tried searching online and found some links from the people who would face it the most : truckers(international too), please see post #38(2 posts above yours).

The situations mentioned here are anyway accepted as a problem for BS6. Not just truckers, any vehicle that spends most of its time in city traffic or low rpm conditions will have a clogged DPF or go through a manual regeneration process. Apologies if it came out wrong, but the statements like 'this is the end of road for diesel' felt a bit overwhelming for me. Could be because I have a preference for large diesels and wants them to exist so badly

[shancz]

Originally Posted by padmrajravi

I think that is something Mahindra specific.

Very well could be like Fords are already struggling. Now that you've mentioned it, was it a shared tech during the Mahindra-Ford JV days ? Just kidding

Originally Posted by padmrajravi

but the statements like 'this is the end of road for diesel' felt a bit overwhelming for me.

Could be because I have a preference for large diesels and wants them to exist so badly

You're right the statement is overwhelming and I apologise if it made you feel that way. Just some unfiltered thought and also that was intended for the post BS7/8 era when the regulations would make it even stricter for diesels.

Could also be because I have a personal bias against them as mentioned

Originally Posted by shancz

Without the F, we feel the DP hitting out faces while you guys are accelerating out of those turns.

But that being said I do hope that some solution exists for the DPF issues since petrol doesn't make much sense in heavier vehicles.
Also there are other people with differing viewpoints as well.

[gururajrv]

Just being curious with this DPF scenario - I’ve seen threads / posts of customers facing issue with BS6 diesels with Mahindra, Ford, Toyota. Have I missed to notice threads or posts from Hyundai & Tata customers with their BS6 diesels?