[DeOetelaar]

Hi!

Don´t blame me but what is the problem with indian petrol exactly?
I don´t know much about engines but in case of the TSI the smaller engines can use 91 octane here in Europe...... the engine will adapt then but it´s not recommended due to a bit less power.

[Sutripta]

^^^
Hi,
In the context of this thread, sulphur content.
In general, adulteration (of both petrol and kerosene) with kerosene/ naptha.

Also higher octane fuels difficult to obtain, esp. outside metro areas.

Regards
Sutripta

[DeOetelaar]

Originally Posted by Sutripta

^^^
Hi,
In the context of this thread, sulphur content.
In general, adulteration (of both petrol and kerosene) with kerosene/ naptha.

Also higher octane fuels difficult to obtain, esp. outside metro areas.

Regards
Sutripta

Hi,
Thank you. I have also doubt regarding the TSI engines. As I bought my new car 2 years ago I remember that there were only TSI engines available from VW. Later on the other VW brands followed with the TSI and so I got maybe one of the last cars with an old standard engine. Main reason was that the car and engine should be durable and the maintenance should be easy. I think just the FSI had a problem with too much sulphur. It might destroy the catalytic converter but this should be fixed by an update. I didn´t catch anything about sulphur and TSI but no enigine should have a problem with it. I decided against the TSI due to the charger. If you ran out of warranty and the charger will be broken the replacement in Germany would cost 1000-1500 EURO I think. It´s strange for me that nobody here has doubt regarding the charger.

[Sutripta]

Originally Posted by DeOetelaar

It´s strange for me that nobody here has doubt regarding the charger.

In India, mention DSG to an out of warranty car owner, and watch him go white in the face. Actually too many things to worry about. So enjoy the ride while it is running. (Here, sorry to say, German cars do not have a reputation for reliability.)

Regards
Sutripta

[vinj14]

So if 91 and 95 RON have the same sulphur content and if sulphur content is the issue which causes a loss in performance and fuel economy, why would there be a loss in performance and fuel economy when using 91 octane?

[Aroy]

Originally Posted by vinj14

So if 91 and 95 RON have the same sulphur content and if sulphur content is the issue which causes a loss in performance and fuel economy, why would there be a loss in performance and fuel economy when using 91 octane?

Sulfur content impacts the catalytic converter, RON the engine performance. Engines with higher compression run better with higher RON fuel, so using lower RON fuel will reduce efficiency. Many German Petrol engines are higher compression engines so that they can deliver more specific power. Older engines and most of the Japanese engines have lower compression ratios hence are tolerant to lower RON petrol.

[Rehaan]

SUPERB thread, Neil.Bhujbal!

Learnt quite a bit about TSI that i did not know of before!

Originally Posted by anandpadhye

For me, one definate way to check the factuality of the claim in this thread (that TSi is useless in India ...because of our petrol quality) is to use a tankful of speed97 and see if TSi (which is already returning decent FE of around 12kmpl @160kmph, 15/16kmph @100kmph and 9/10kmpl in city traffic), becomes super efficient with speed97 or not.

Would be keen to hear your results on this test!

Remember to drive very light-footedly for the true best results (by forcing stratified mode).

Also, you might need to run for a while (perhaps a tank full?) first, so as to clean out the cat-con of the NOX, before the car switches over to stratified mode?

Originally Posted by Shivank

Now come back to India. Because 91 RON is more popular here than 95, the stratified mixture is now made to run much richer compared to what's offered in European cars, i.e, instead of setting stratified mixture at 1:40 manufacturer now changes the Fuel-air ratio as per the the quality of fuel used here. Let's say, reduces it from 1:40 to 1:25 or 1:20.

You've raised an interesting point here. In some ways, this problem is its own solution.

Lower RON fuel in India --> Less extreme stoichiometric ratio --> Less NOX produced --> Counterbalances the higher sulphur content in most Indian fuel ?

Though of course, IF this is true, the end result is still a less effective stratified mode, with regards to fuel efficiency.

What say?

cya
R

[Shivank]

Originally Posted by Rehaan

You've raised an interesting point here. In some ways, this problem is its own solution.

Lower RON fuel in India --> Less extreme stoichiometric ratio --> Less NOX produced --> Counterbalances the higher sulphur content in most Indian fuel ?

Though of course, IF this is true, the end result is still a less effective stratified mode, with regards to fuel efficiency.

What say?

Well, of course, the mixture is less effective than what it should have been. But then, you cannot blame the manufacturer for using TSi as a wrong advertising gimmick, and also we can't conclude that these engines are useless here in our market. They are less effective, but they are, to some extent, more effective than conventional engines anyway.

[Sutripta]

Originally Posted by Rehaan

SUPERB thread, Neil.Bhujbal!

Sorry, I beg to differ.
This thread is entirely devoid of any hard facts. Seems to be based on one scrap of information presented in post# 35.

Lower RON fuel in India --> Less extreme stoichiometric ratio --> Less NOX produced --> Counterbalances the higher sulphur content in most Indian fuel ?

No, not really.
RON and stoichiometric ratio should be independent of each other.
If the fuel has sulphur, it is going to form Barium Sulphate in the NOx adsorber. Regeneration from NOx takes seconds. But Barium Sulphate is very stable. Regenerating from it takes minutes, rather than seconds. And an elevated temperature, possibly needing an auxillary heating source.

If the fuel has say 5 times the sulphur than design for, regeneration will occur 5 times as often. So optimal working:- no, but working nevertheless.

Question therefore is what permanent/ irreversible damage is caused by excess sulphur. Is the adsorber life determined by the number of regeneration cycles it has undergone, or by something else?

Even more important is what happens if say the sulphur content is 200 times the design limit. (This will happen if the vehicle runs on adulterated fuel (petrol/ kerosene mix). Sometime during its life, this will happen.) What happens then?

These questions are really not answered in this thread.

Regards
Sutripta

[Aroy]

Originally Posted by Sutripta

Even more important is what happens if say the sulphur content is 200 times the design limit. (This will happen if the vehicle runs on adulterated fuel (petrol/ kerosene mix). Sometime during its life, this will happen.) What happens then?

These questions are really not answered in this thread.

Regards
Sutripta

On a lighter vein, go get an old non-mpfi petrol or better still an DI/IDI diesel, and run merrily on adulterated fuel. Pollution be dammed (you cannot help - it is the bad fuel!)

On a more serious note. Excessive sulfur has to be absorbed in the CATCON, which it self has a limited capacity. 2 times may be border line, 5 times doubtful and more than that, you might as well as have no CATCON. I did read some where that Mercedes were having problems with high sulfur fuel, as the CATCON just got swamped with excess sulfur.

I was wondering, what happens when the CATCON is jammed and cannot function any more, due to excess pollutants in the fuel.

[Sutripta]

Originally Posted by Aroy

On a lighter vein, go get an old non-mpfi petrol or better still an DI/IDI diesel, and run merrily on adulterated fuel.
Certainly not merrily.

On a more serious note. Excessive sulfur has to be absorbed in the CATCON, which it self has a limited capacity. 2 times may be border line, 5 times doubtful and more than that, you might as well as have no CATCON.

Don't get what you are saying.

Regards
Sutripta

[Aroy]

Originally Posted by Sutripta

Don't get what you are saying.

Regards
Sutripta

From what I have read, the sulphur in the exhaust gasses is absorbed in the CATCON. This is then treated and released to atmosphere. If all the active material in a CATCON is used up before the absorbed sulphur is processed, then the CATCON cannot absorb more sulphur, and is rendered ineffective

The question is what will happen in such a case?

Mercedes Says Dirty Fuel Problematic in U.S.
How can you tell a catalytic converter is bad
The effects of the catalytic converter a... [Environ Sci Technol. 2002] - PubMed - NCBI

[Sutripta]

In the context of this thread, the reaction with sulphur of the NOx adsorber is an undesirable sideeffect. As long as the sulphur in the fuel is not zero, it will happen. And will have to be taken care of. By regeneration. As stated, regenration from the N compounds takes seconds, from the S compounds minutes.

As to how often this regeneration is needed, for both cases, in typical implementations, it should be there somewhere on the internet. Which I'm sure you can find, and then educate us.

Regards
Sutripta

[Rehaan]

Originally Posted by Shivank

..But then, you cannot blame the manufacturer for using TSi as a wrong advertising gimmick, and also we can't conclude that these engines are useless here in our market.

Nowhere have i said that. I have steered clear of that whole part of the discussion! Am only interested in the technical aspects here.

Personally though, i think its a good thing that TSi engines are being brought it. However, i also think its a good thing that we are being educated about the finer points of their functioning.

I love the 1.8TSi.

Originally Posted by Sutripta

Sorry, I beg to differ.
This thread is entirely devoid of any hard facts. Seems to be based on one scrap of information presented in post# 35.

I learned a lot from the first post itself. Beyond that, despite differences in opinion, its still an extremely interesting discussion. I'd still call it a superb thread!

Originally Posted by Sutripta

No, not really. RON and stoichiometric ratio should be independent of each other.

Agreed. Though after reading this post i was wondering if its possible that lower RON = richer ratio chosen = less NOx ?

Originally Posted by Sutripta

If the fuel has sulphur, it is going to form Barium Sulphate in the NOx adsorber. Regeneration from NOx takes seconds. But Barium Sulphate is very stable. Regenerating from it takes minutes, rather than seconds. And an elevated temperature, possibly needing an auxillary heating source.

Thanks! I was wondering about the time-frame here. Though i'm still a bit unclear :

Lets assume "high-sulphur" is 150 ppm, and "low-sulphur" is 15ppm.

Q1) Say i drive for 30 mins in stratified mode with low-sulphur petrol, how many minutes of driving in homogeneous mode will it take to clear out the NOx?

Q2) Say i drive for 30 mins in stratified mode with HIGH-sulphur petrol, how many minutes of driving in homogeneous mode will it take to clear out the Barium Sulphate?

Q3) How many minutes of driving in stratified mode with HIGH-sulphur petrol will it take for the catcon to reach its maximum storage amount of NOx / Barrium Sulphate and then forcefully switch over to homogeneous mode?


^ This should give us a more realistic idea of if the TSi is actually useless or not with high-sulphur fuels.


Thanks,
R

[Sutripta]

Originally Posted by Rehaan

Lets assume "high-sulphur" is 150 ppm, and "low-sulphur" is 15ppm.

Q1) Say i drive for 30 mins in stratified mode with low-sulphur petrol, how many minutes of driving in homogeneous mode will it take to clear out the NOx?

A few seconds.

Originally Posted by Rehaan

Q2) Say i drive for 30 mins in stratified mode with HIGH-sulphur petrol, how many minutes of driving in homogeneous mode will it take to clear out the Barium Sulphate?

AFAIK, ~5 mins. At higher power. Temperatures have to be maintained.

Originally Posted by Rehaan

Q3) How many minutes of driving in stratified mode with HIGH-sulphur petrol will it take for the catcon to reach its maximum storage amount of NOx / Barrium Sulphate and then forcefully switch over to homogeneous mode?

Don't know!
Considering that OBD was legislated for emission compliance, I'm sure these modes will show up on a scangauge. Someone willing to do the experiment?


Regards
Sutripta