[delusional_fool]

Thanks for this thread, its very informative especially for a newbie car owner like me who just bought a BS6 Diesel I20.

I have a few more questions apart from the ones answered already -

1. Does all the BS6 cars have active regen functionality? I own a BS6 I20 diesel and don't see anything about active regen in the manual and don't any active regen indicator in the IC.

2. For passive regen, how can I find if my DPF is running at 250-400degC? Is it ok to assume that if I drive my car for more than 25 Mins at speeds >20KMPH, passive regen would have happened clearing the soot?

3. Should I be consciously driving always above 2K RPM in order to avoid DPF issues? Even though the user manual is suggesting to shift gears between 1.5 to 1.8K RPM? Does this mean the 6th gear has pretty much no use even in highways since my car cruises at 100 to 105 KMPH at around 2K RPM in the 5th gear

So far I've been doing mostly highway runs but starting Jan, I will be using my car primarily in the city - Roughly 18KM one way that will take ~50mins with ~40% of the distance involving frequent start-stops and I'm worried its gonna affect the DPF. Any suggestions for avoiding DPF issues in this scenario, maybe once a month highway joyride? Will that be sufficient?

[nischaltopno]

@ninjanayak, thank you so much for providing so much of information regarding DPF. .

Question: The calibration requires a software or/and a hardware tweak? In case of hardware changes how much is the %age of change expected for vehicles manufactured at the beginning of BS6 era - can that be easily retrofitted/changed?

[Capt.Ashu]

Hello to all members of Team BHP. This is my first post.
A brief introduction: I have been following Team-BHP for a long time now, finally decided to join as a member. I am a seafarer by profession and hail from Uttarakhand. I have been driving and sailing for the past 20 years. Both DL and my Certificate Of Competency are due for renewal in 2022

Coming back to topic at hand, first of all thank you @ninjanayak for providing your technical expertise to clear our doubts.

Please provide your valuable feedback on my below queries:
1. What special precautions would you recommend to people who drive 90% in mountains, where maintaining constant RPM is a challenge?
2. Diesel has always been the primary fuel in our region as Petrol engine means low fuel economy = low range (Petrol pumps with good quality fuel are scarce) and low torque. Based on the above, how are the BS VI compliant commercial vehicles dealing with DPF issue?
3. Does colder atmospheric temperature affect DPF clogging frequency? If yes, what special precautions required?
4. Because of job my car stays unused for a period of 3 months. I would like to buy XUV 7OO with AWD but it is only available in diesel, will it pose extra threat with regards to DPF (I know diesel vehicles should not be kept stationary for such a long period but say I keep minimum fuel in tank during that period and follow empty-refill cycle before reusing the car)?

Regards,
Ashu

[ninjanayak]

Originally Posted by Ravi Parwan

Why do we need to inject fuel to raise the temperature in the DPF? can this not be done using an electric heater?

Active regen requires 600+degC temperature in the DPF sustained for approx. 25 mins depending on the vehicle. This amount of energy would require a very high current or voltage power supply if electrical heaters are to used.
Diesel is a very energy dense fuel, so a small amount of diesel is sufficient to reach this temperature. Its not that electric heaters cant be used, its just a matter of efficiency.

Originally Posted by delusional_fool

1. Does all the BS6 cars have active regen functionality? I own a BS6 I20 diesel and don't see anything about active regen in the manual and don't any active regen indicator in the IC.

Congrats on the new car!! All DPFs will require active regen functionality.

2. For passive regen, how can I find if my DPF is running at 250-400degC? Is it ok to assume that if I drive my car for more than 25 Mins at speeds >20KMPH, passive regen would have happened clearing the soot?

Yes, driving at >20kmph speeds after the vehicle has warmed up should suffice in getting these temps.

3. Should I be consciously driving always above 2K RPM in order to avoid DPF issues? Even though the user manual is suggesting to shift gears between 1.5 to 1.8K RPM? Does this mean the 6th gear has pretty much no use even in highways since my car cruises at 100 to 105 KMPH at around 2K RPM in the 5th gear

2000rpm is a generic speed value I suggested, if the manual suggests you to maintain 1500 to 1800rpm for gear changes you could stick to it.

So far I've been doing mostly highway runs but starting Jan, I will be using my car primarily in the city - Roughly 18KM one way that will take ~50mins with ~40% of the distance involving frequent start-stops and I'm worried its gonna affect the DPF. Any suggestions for avoiding DPF issues in this scenario, maybe once a month highway joyride? Will that be sufficient?

Since you mention that your commute will have ~40% time in start-stop conditions, maybe go to rural or slightly high speeds areas once every 10 days if possible along with the highway joyride.

Originally Posted by nischaltopno

Question: The calibration requires a software or/and a hardware tweak? In case of hardware changes how much is the %age of change expected for vehicles manufactured at the beginning of BS6 era - can that be easily retrofitted/changed?

I'm not sure what you mean by hardware or software changes? maybe clarify it a bit more. Software change would just entail re-flashing the ECU with new
calibration and hardware changes are rarely done since it is expensive.

Originally Posted by Capt.Ashu

1. What special precautions would you recommend to people who drive 90% in mountains, where maintaining constant RPM is a challenge?

As I mentioned in previous replies, avoiding overloading and driving at full throttle all the time in these conditions should be sufficient. During uphill driving the DPF should be able to clear the soot deposited.

Originally Posted by Capt.Ashu

2. Diesel has always been the primary fuel in our region as Petrol engine means low fuel economy = low range (Petrol pumps with good quality fuel are scarce) and low torque. Based on the above, how are the BS VI compliant commercial vehicles dealing with DPF issue?

Commercial vehicles have been thoroughly tested in these conditions and dont face DPF issues as the amount of passive regen is very high in trucks above 2L capacity. Small trucks could face some issues but no major field complaints so far.

Originally Posted by Capt.Ashu

3. Does colder atmospheric temperature affect DPF clogging frequency? If yes, what special precautions required?

During our testing, we didnt face any major problems with cold temps, so it should work just fine.

4. Because of job my car stays unused for a period of 3 months. I would like to buy XUV 7OO with AWD but it is only available in diesel, will it pose extra threat with regards to DPF ?

No problems to DPF if left unused for extended periods of time. Just ensure that no damages to wires or sensors happens during this due to pests or animals.

[nischaltopno]

Originally Posted by ninjanayak

I'm not sure what you mean by hardware or software changes? maybe clarify it a bit more. Software change would just entail re-flashing the ECU with new
calibration and hardware changes are rarely done since it is expensive.

Thanks for the response and to an extent I got the answer.
By "hardware" I meant mechanical changes and "software" I meant making changes to the ECU program/code - sorry that's a rub off from software industry. .

[John P Daniel]

Hi. Thanks for taking time to provide such insights into a highly debated topic. Coming to my queries,
1. Regarding active regen, I've heard of cases where even active regen has failed to clear DPF. In one such case, the car was driven at high rpm intentionally and only then the active regen was passed. From this observation, high rpm driving can negate the need for active regen. Is that correct?
2. Is there any modifications in fuel injector for BS6 compared to BS4? Many cases I heard mentioned the fuel injector was also damaged when active regen had failed.
3. Is it ok to fill BS4 fuel if BS6 fuel is unavailable? If so, what precautions to take to ensure it does not cause severe damage?

[ninjanayak]

Originally Posted by John P Daniel

1. Regarding active regen, I've heard of cases where even active regen has failed to clear DPF. In one such case, the car was driven at high rpm intentionally and only then the active regen was passed. From this observation, high rpm driving can negate the need for active regen. Is that correct?

No, its not practical to drive at high rpm all the time and its not guaranteed that passive regen will occur by driving at high RPMs, so active regen is required.

2. Is there any modifications in fuel injector for BS6 compared to BS4? Many cases I heard mentioned the fuel injector was also damaged when active regen had failed.

BS6 injectors are capable of upto 7-8 injections per stroke (5 injections in case of cheaper variants), whereas BS4 injectors required only 3-4 injections per stroke, that is the main difference.
DPFs will not cause the failure of injectors, it is other way around. Faulty injectors cause the DPF to fill up quickly or the active regen to fail.

3. Is it ok to fill BS4 fuel if BS6 fuel is unavailable? If so, what precautions to take to ensure it does not cause severe damage?

It's best to avoid using BS4 fuel as much as possible, because higher Sulphur content of older gen fuel can poison the catalyst over the long term and cause all sorts of problems not just to the DPF.

[Nikhil Beke]

I think most of the common queries have been satisfactorily resolved: just adding two more to make this thread a complete guide to DPF queries:
1. Any truth in recommendations on a specific brand of diesel to ward off DPF issues? Few claims indicated Shell/Reliance usage led to fewer DPF problems.
2. What use (if any) are DPF cleaner fuel additives ("Liqui-Molly" et al)? Are they potentially hazardous? I was strictly told to stay away from them.

[Mortis]

@Ninjanayak very interesting and timely thread.

I had a question about diesel additives, though I'm not sure if it is something you have tested for.
The use of additives like Acetone/Addon D/System D help in getting rid of the black soot from diesel exhaust and reduce smoking. It is something that works very well and I myself have seen thier effect on my old diesel Swift.

I was wondering if their regular usage can help reduce or prevent DPF clogging in BS6 engines ? I'm especially interested in Acetone as an additive because it helps in fuel atomisation and a hotter, cleaner burn. The effects are noticeable in both diesel and petrol car emissions (PUC). Hopefully you could shed some light on this.

[ninjanayak]

Originally Posted by Nikhil Beke

1. Any truth in recommendations on a specific brand of diesel to ward off DPF issues? Few claims indicated Shell/Reliance usage led to fewer DPF problems.
2. What use (if any) are DPF cleaner fuel additives ("Liqui-Molly" et al)? Are they potentially hazardous? I was strictly told to stay away from them.

Originally Posted by Mortis

The use of additives like Acetone/Addon D/System D help in getting rid of the black soot from diesel exhaust and reduce smoking. It is something that works very well and I myself have seen thier effect on my old diesel Swift.
I was wondering if their regular usage can help reduce or prevent DPF clogging in BS6 engines ? I'm especially interested in Acetone as an additive because it helps in fuel atomisation and a hotter, cleaner burn. The effects are noticeable in both diesel and petrol car emissions (PUC). Hopefully you could shed some light on this.

I mean from a technical perspective, "premium fuel" with higher Cetane number should produce good combustion and reduce emissions. There may be some truth to it but a detailed study here would be necessary to conclude I guess.
For your piece of mind, you may use additives, but frankly most modern engines already are well optimized to meet emissions at all load points, hence these additives may cause very little or no change. Unless the OEM specifically suggests you to use a certain product, it's best to avoid these things I guess.

[fhdowntheline]

@ninjanayak, thanks for taking the time out to share your expertise. Referring to your points about SCR vs LNT, wherein you mentioned that SCR is a more robust and efficient system, is there any factor of the engine size here, i.e., its observed that most diesel engines 1500cc and below are using LNT (notably Hyundai), whereas the larger engines are using SCR. Is it the case that LNT may be sufficient for smaller capacity engines?

If this is not true, then what are the chances that over a period of time, the LNT based engines may actually degrade in terms of their ability to comply with NOX emissions?

[--gKrish--]

Originally Posted by ninjanayak

Here are some basics about BS6 and DPF in general.
BS6 emission regulation came into effect on April 1st 2020 all over India. The aim it is to improve air quality in our country and reduce tail pipe emissions. In diesel cars there is 70% reduction in NOx (Nitrogen Oxides) emissions and 90% reduction in PM (Particulate Matter) emissions compared to BS4.

Hi Ninjanayak,

Thanks a lot for this thread and all the information you are sharing with us.

Coming to my question, I often see the comparison between the emissions from BS6 and BS4 engines but usually info about how we arrive at these numbers is missing. Is the comparison done for the total emission of BS6 and BS4 engine? (inclusive of the emission from BS6 when regen happens?).

I often see articles mentioning that EGR reduces upto XX% of NOx emission, but we all are aware that the emission reduction is different at different RPM ranges as the percentage of EGR varies across the RPM range.

So I believe, it should be specified along with the emission reduction, at what operating RPM and load%, these measurements were taken for both engines. Also, is the emission during regen and normal working cycle varying by a large extent?

[daspranab]

Originally Posted by ninjanayak

I am a Diesel Calibration Engineer by profession specializing in DPF calibration for Indian vehicles . I see a lot of queries and some misunderstanding about BS6 in general and DPF specifically on this forum. So as an expert I would like to clarify some of your doubts and questions regarding these things. So post your questions and queries below and I will try my best to answer them for you.

Here are some basics about BS6 and DPF in general.
BS6 emission regulation came into effect on April 1st 2020 all over India. The aim it is to improve air quality in our country and reduce tail pipe emissions. In diesel cars there is 70% reduction in NOx (Nitrogen Oxides) emissions and 90% reduction in PM (Particulate Matter) emissions compared to BS4. PM reduction was done by using a DPF which traps these PMs and NOx reduction is done with the help of either EGR+LNT(NSC) or EGR+SCR technology.

A DPF needs to periodically regenerated when its completely filled with soot particles coming from the Engine and this is generally done at high temperature inside the DPF. Diesel fuel is deliberately released in the exhaust of the vehicle which is burnt in the Oxidation catalyst (DOC) and the heat released from this combustion is used to burn the soot collected in the DPF.
This is the basic principle by which a DPF system works without getting too technical about it.

So post your questions below and lets learn

I have a naive ask: if I keep a diesel car (1) at home, with occasional travel to long distances; or (2) commute frequent short distances and take it for regeneration whenever there's a warning, will it be sufficient?

Let me explain: I'm very keen to have a diesel car for the aforesaid two purposes due to their (driveability ÷ fuel price) ratio, particularly since CNG/LNG/flex fuel are uncertain at best and I'm very fond of touring by road.

One more question: will the differential maintenance of a diesel car offset the savings on differential fuel price, given my usage pattern, in medium (~10 - 15k km/year) term?

Since used BS IV diesel cars are at a premium in comparison with new BS VI ones, I don't bother you by asking if going after a used one would be an option.

Please let me know if you have any specific recommendation, including model, make, trim, etc. knowing we would generally travel as couple occasionally accompanied by son.

Thank you for your illuminating post

[gadadhar]

Thanks for the very useful information

I own a 2021 Fortuner Diesel and was told not to switch off the engine while the DPF generation warning is on. What can be the consequences if the engine gets switched off by oversight ? Are there any further steps to be followed to minimize if there is an impact

[Wildy]

Hi,@Ninjanayak, Iam posting this query on behalf of my friend Mr. Dheerender Dev Singh from Jalandhar.


Thanks for this awesome thread with loads of great information. Maximum queries have been dealt in a detailed manner regarding DPF issues. I bought Fortuner 4x4 mainly to explore the places where roads are treacherous where 4x4 is a must and also to enjoy both the off-roading and the beautiful unexplored places.

My question is, if we have to drive in 4x4 low in 2nd/3rd gear or even on 1st on a steep inclined road where there is lots of rocks and pebbles, for 50 to 60 kms continuously with speeds varying from as low as 2km/hour (just crawling) to 20kmph, will DPF get clogged or would it regenerate normally?


I have been on such route once in Storme 4x4 in Padder Pangi Road till Sach Pass where one side is Jammu & Kashmir and the other side is Himachal Pradesh and the the total distance is about 60kms. Road is absolutely treacherous but equally thrilling. In Safari Storme BS4,I had got no problem whatsoever and it was driven the same way as I have mentioned above. I want to take my Fortuner there with my family and hence requesting you to guide me with your opinions/suggestions if any.

Thanks & Regards,

Dheerender Dev Singh