[5252rpm]

I have some queries on the same.

1. How much fuel will help? If BS6 fuel is used in BS6 diesel car , are the cases of DPF issue any better? What is the status of BS6 fuel availability in our fuel stations?

2. Will a remap help ? Has anyone noticed any changes?

[Aviator_guy]

Originally Posted by 5252rpm

I have some queries on the same.

1. How much fuel will help? If BS6 fuel is used in BS6 diesel car , are the cases of DPF issue any better? What is the status of BS6 fuel availability in our fuel stations?

Did not get your question. Only BS6 fuel is sold now after the norms have kicked in from 2020.

[5252rpm]

Originally Posted by Aviator_guy

Did not get your question. Only BS6 fuel is sold now after the norms have kicked in from 2020.

Even though the norm came in Mar 2020, not every fuel stations was having BS6 fuel then. I am not sure if this is fixed now. BS4 fuel in BS6 cars were a concern back then, getting attributed to recurring DPF issues. Now across the nation, are we getting only BS6 fuel?

[Aviator_guy]

Originally Posted by 5252rpm

Even though the norm came in Mar 2020, not every fuel stations was having BS6 fuel then. I am not sure if this is fixed now. BS4 fuel in BS6 cars were a concern back then, getting attributed to recurring DPF issues. Now across the nation, are we getting only BS6 fuel?

Well, this is news to me that BS4 fuel can still be sold legally. May be someone could throw more light.

[abirnale]

Originally Posted by Omkar

Requesting you to please contribute with additional tips for cars with DPF.
….
BHPian ph03n!x has done over 55,000 km with his Thar and hasn’t had any DPF related issues.

Even though our cars are getting modern and a lot of induced abstraction from the tech for owner, it would still help to be an informed owner vs just a regular owner who doesn’t understand what his/her machine is. What I am trying to say is - one must do a few things always in their automobile ownership journey:

• Understand your car as much as you can - this involves spending some time with the machine.
• Read your Car’s user manual thoroughly - it helps not just technically to understand what it is made up of but also helps deal with it’s tantrums if any.
• The car is meant to be used - cannot be forever parked in garage and used for only routine commutes that doesn’t even see the RPMs above 1800 - 2200 band or beyond the speeds of 30kmph! You probably should have bought an EV or a gasoline car and not a diesel mill.

Like the Thar mentioned above, my XUV7OO is so far trouble free from DPF related issues. It’s been almost 50K kms in about 18 months or so - last three months the car has not even done 1000kms total though! The point I am trying to make is - the PDF problems don’t happen overnight. It takes time to accumulate soot/ particulate matter and get to the level of catastrophe! Almost the whole of of July, August and Sept - my car did not attain the speeds more than 50kmph, did not run in one go for more than 10kms. But what I definitely kept doing in such times is - a random morning, take it out for a spin on NICE road for about 20kms and try it to rev higher (use mode M on gear-stalk as needed!). Not sure if that is a right thing to do, but I am pretty sure that this isn’t the phase my car will see for long. She isn’t a garage queen - she is meant to be on the prowl

[Airavat]

Originally Posted by Omkar

No lugging or driving at low revs
Attachment 2503568
This one’s for the manual transmission owners and a good practice in general too. Once you have your car properly warmed up, don’t drive at slow speeds in higher gears. Keep the engine hot and let the soot burn off. For automatic cars, the gearbox logic takes this into account and keeps the engine revs high and never lugs.

Thanks for this informative post Omkar.

I drive a Toyota Hilux MT which has done over 8000 kms. My weekly drive is up to 250 kms (in 4 days) in free flowing traffic. The passive regeneration starts when the DPF level is at 4 bars. It reaches this level at every 300/325 kms with my driving pattern. The regen completes within 10 kms of drive. During the regen I drive in lower gears trying to maintain the revs over 1500 rpm.

The question I have is, if the soot only burns when the regen is in progress or it burns off even during normal operation.
What is the recommended in gear rpm that should be maintained ideally in a diesel engine (note that I have switched from a Swift petrol to Hilux, so this is my first time with a diesel)?

Thanks!

[Revvatron]

Originally Posted by Airavat

Thanks for this informative post Omkar.

The question I have is, if the soot only burns when the regen is in progress or it burns off even during normal operation.
What is the recommended in gear rpm that should be maintained ideally in a diesel engine (note that I have switched from a Swift petrol to Hilux, so this is my first time with a diesel)?

Thanks!

The regen only kicks in after soot accumulated reaches a certain level. If you are driving on highways or any long distance then soot burns off normally due to high temperature which is reached during such drives.

For your second question, if you are driving long regularly(at 60-80kmph) for certain period of time then rpm doesn't matter much. Otherwise around 2000 rpm should be good incase you had too many short drives continuously.

[SKC-auto]

Originally Posted by Airavat

The question I have is, if the soot only burns when the regen is in progress or it burns off even during normal operation.
Thanks!

As I understand, during regen more fuel is injected, which means more unburnt fuel reaches the DPF, where it burns the soot, during normal operation too we will have some unburnt fuel which will reach the DPF to burn the soot.

[Drlmtukkar]

A big thank you Omkar for making things so simple and interesting. I’ve understood the facts so clearly now - all thanks to you. And yes I’ve shared this link with lots of my friends. Yes everyone using a BS6 diesel needs to understand this one accept clearly.
I’ve got just one question - Can the passive regen be done at speeds of 90-110kmph or we need to drive only around 60-70kmph.

[Deucalion]

My family owns a 2022 Altroz Diesel and have been using it mainly in the city for a year or so since we bought it, my dad primarily uses it for to and fro from his office to our house, which is a short distance of 2 kms one way. We have only seen the DPF light glow once and since my father works in a dealership, we got regen done at the service centre. The car has run around 14k till date and the DPF symbol appeared only once, that is because whenever I take the car out for a spin, my nature of driving is aggressive in general so I rev and don't change gears outside 2.5-3k rpm and take the car out on a bypass close to my house and rev for 15 minutes or so at speeds of around 80-100 in 3rd or 4th gear specifically. We take the car out on highways occasionally and that is a contributing factor too. But, there is an issue of Diesel mixing in oil and the oil level rising. Still have no idea how to deal with that.

[Innysta]

Originally Posted by Drlmtukkar

I’ve got just one question - Can the passive regen be done at speeds of 90-110kmph or we need to drive only around 60-70kmph.

For passive regen in city drives, it is advisable to do above 1200rpm (60-70kmph) with AC and Lights ON. Better fuel quality (the best we can do is stick to crowded pumps*/COCO outlets), Driving at optimum gears (do away engine lugging (Toyota Innova Crysta : Official Review)) are the key factors.

*I was avoiding crowded pumps but resulted in entire DPF unit replaced (Toyota Innova Crysta : Official Review) under warranty. Later came to know from localites that the pumps i used were known for adulteration.

[audioholic]

Originally Posted by Airavat

The question I have is, if the soot only burns when the regen is in progress or it burns off even during normal operation.
What is the recommended in gear rpm that should be maintained ideally in a diesel engine (note that I have switched from a Swift petrol to Hilux, so this is my first time with a diesel)?

Thanks!

The key element to soot burn off or passive regeneration is high exhaust gas temperature over an extended amount of time. This is achieved only under high load and high speed conditions. However with a large engine like the 2.4 or 2.8 Toyotas, the engine is hardly under load and EGT never rises to the levels that soot can burn off. Only if you are doing a highway run with full load of people and luggage, the engine would actually reach higher EGT. The Toyota GD engine is also one of the most thermally efficient engines which means less heat is let out or wasted. Thats the reason to support DPF regeneration, they have a fifth fuel injector at the exhaust which will inject diesel and burn it to increase EGT.

That's the reason with these engines, no matter how hard you drive, there is a practical limitation against passive regen. In my car, the regen frequency only changes with fuel and FE and never by driving condition. Hence, there is no point in trying to run at high RPM or driving hard in these engines. Just let the system do it's job. In fact if we drive with a light foot the soot accumulation is also reduced and the regen interval automatically becomes higher.

Perhaps for a smaller engine like 1.5L this driving hard trick would work, but definitely not for the larger engines. It might just make matters worse. In my Crysta, it sees prolonged city usage or highway usage and never a mixed use. Even then in the last 34k kms of use, there was never a need to do manual regeneration or DPF light blinking. Regen kicks in 200-250kms or so and does it's job in ten minutes be it on the highway or in bumper to bumper traffic.

[Kosfactor]

Originally Posted by Deucalion

We take the car out on highways occasionally and that is a contributing factor too. But, there is an issue of Diesel mixing in oil and the oil level rising. Still have no idea how to deal with that.

I do not think driving the engine at a higher speed is going to do anything, just drive on the highway for a hour or so at normal speeds and it would take care of itself. Specific to Altroz we have a few other cases of oil dilution elsewhere in the forum, it may need to be inspected before you pack up the engine for good.

[narayans80]

Before taking a plunge, had invested enough time reading through the diesel candidate threads. Nearly a year later 385xx on the clock without any DPF issues, here's how it is operated:

• The only thing I consciously take care in my BS 6.1 Alcazar is the pumps where it is being fueled. According to my stats, 54% out of 64 refuels it has been at the Singaperumalkoil IOCL COCO pump, only once has it been refueled outside a COCO pump.
• The car is mostly driven in the higher gears, because its owner wants to preserve his sanity over the 80 km a day commute.
• It is driven in a fuel efficient manner 9 out of 10 days. Seeing 2000 rpm is a once a month/quarter type event, mostly sees 1500-2000 rpm on a daily basis.
• Running a diesel car has bigger risks like injector failures than the DPF failures. Even my petrol engined cars were not driven that dry.
• So far never paid attention to the engine oil.

One of the contrarian case study in the forum is Naetik30's Alcazar Diesel AT. He drives 60 km a day, takes it on highways and yet sees a DPF regen problem every 10K. The latest being right out of a highway drive.

Is it fuel quality? Or is it the way AT is shifting aggravating the problem?

Courtesy of Covid, I haven't seen a BS6 diesel that's gone into the 6-digit figure yet. The highest so far in the forum is Ashis' Seltos at 65K. So the long term behavior is yet to be seen.

[gauravdgr8]

Originally Posted by Omkar

If you don’t want to deal with the DPF and the strings that it comes attached with, you can opt for a used car that doesn’t have a DPF. But if your usage is primarily going to be short trips around the city, it’s best if you consider other fuel types like petrol, hybrid or even electric.

Brilliantly explained Omkar. Would surely make it super easy for any one to understand what's going on with the car and whether one should go for Diesel with their usage pattern.

Originally Posted by ashis89

And I avoid premium diesels at all cost (this is recommended by OEMs as well). During early days of BS6, anyone filling premium diesel into their Seltos used to get DPF clogged.

Why would this be. Any specific reason identified? Isn't premium diesel supposed to be much cleaner?