[oxyzen]

Does this mean I have 2 injectors per cylinder? (one for each mode)

What if I remove the sensor that detects high Nox? Anyway the cata is already damaged. What if I remove the cata altogether?

[Sutripta]

^^^
Single injector.
Injection during intake stroke or compression stroke.

Its a NOx adsorbtion unit. When it gets full, a downstream NOx sensor picks up the increased NOx. So removing Cat/ Adsorbtion unit will not help.
Adsorbtion unit can be regenerated.

Originally Posted by Neil.Bhujbal

[*] High speed, high load – Homogeneous mode.[/list]Q.Why are these stratified engines useless in India ?


A.They need min 95 Ron fuel. Anything less then that has high sulphur
content which damages the new nitrogen oxide storage catcon.

Originally Posted by Neil.Bhujbal

You dont need high octane fuel for the engine but for the exhaust system of these engines to work efficiently.
....
Problem is the low octane fuel which has high sulphur content.

Originally Posted by Neil.Bhujbal

Sulphur content in 95 octane fuel is less then 10 ppm compared to 15 ppm which is found in 91 octane fuel.

Hi,
I, for one, do not see the connection between octane rating and sulphur.
I agree with

Originally Posted by sgiitk

95RON is the standard for Premium in Euro III & IV. I do not see how can 95RON against the 91 Standard have anything to do with Sulphur. The specification vis a vis Sulphur are the same for Standard and Premium.

Once this octane/ sulphur thing is cleared up, we can move on to the Barium Sulphate thing.

[Neil.Bhujbal]

Shucks.. My bad guys. The stratified charged engines need SUPER UNLEADED FUEL (97 octane) (this is a Mercedes specific document but i am sure its more or less same for other manufacturers too) In-case unavailable 95 Octane can be used but will cause loss in power & fuel efficiency. (Proof of this is a document which i will need to scan and then put up.) Sorry for the goof up. Something IS WRONG & i am not able to upload the pic of first document.I am even unable to multi quote & add smiles . Will put up the document as soon as i can.

[Sutripta]

Originally Posted by Neil.Bhujbal

In-case unavailable 95 Octane can be used but will cause loss in power & fuel efficiency. (Proof of this is a document which i will need to scan and then put up.)

Using lower octane than recommended will be accommodated (if possible) by strategies like retarding ignition or reducing boost etc. Well known (and logical) that there will be a loss of power and FE. Proof really not necessary. Until the paper has something more.

Regards
Sutripta

[Neil.Bhujbal]

Originally Posted by Shivank

Hi again, Neil.

Very interesting thread. I am just glued here!

I did a fair bit of Googling and after that it seems these engines can't definitely be tagged as useless! As per the information I have gathered, manufacturers tune engines as per the fuel available here.

In Europe or anywhere else where 95 RON is the default choice for these cars, stratified or lean mixture, lets assume, is set to be at 1:40 (Fuel:Air) against the stoichiometric ratio of 1:14. Under light loads this is good for fuel consumption. Right?

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. Getting my point?

This way, the engine still runs leaner/saves fuel at light loads (considerably). And all that without harming the engine or cat-con life.

PS: Hope, I made sense here. I am just sharing what I understood.

What your saying is quite possible but. But changing the limit of AFR in stratified mode from 1:40 to 1:25 is not going to change the sulphur content in the fuel. So that will still be damaging the catcon.

Originally Posted by Aroy

Some interesting links on pollution
Tier 2 Gasoline Sulfur Program | Fuels and Fuel Additives | US EPA
Reformulated Gasoline (RFG) | Fuels and Fuels Addtives | US EPA
http://www.meca.org/galleries/default-file/sulfur.pdf
http://www.iocl.com/Products/MS_BS_I...0_Current_.pdf
UK Fuels - Change in the level of Sulphur in BP Fuel

At present both 91 and 95 RON fuels have same sulfur - 50 ppm. The 97 RON is supposed to have 10 ppm.

As all the high end petrol vehicles use high compression engines, they will benefit anyway from 97 RON fuel.

Yes they will surely benefit & yes ones again to 91 & 95 octane fuel having the same sulphur amount. I goofed up on the octane no thing. Octane 97 should be used. At least that's what Mercedes is recommending for CGI engines. I will try to find what has skoda done to make them run on 95 octane. But finding that out might take time.



And here we are taking into consideration octane no not for engine performance & efficiency but for the sulphur content which damages the catcon being used in these engines.

Originally Posted by ~~h

brilliant write up, thanks for sharing.



Qn: does it mean if you disable the sensor or fool it some way the engine will work in stratified mode ?
Of course it's not good for the environment but with the low quality fuel that (or frequent cat con flush) seem the way to go.

No idea on that,

Originally Posted by Sutripta

Using lower octane than recommended will be accommodated (if possible) by strategies like retarding ignition or reducing boost etc. Well known (and logical) that there will be a loss of power and FE. Proof really not necessary. Until the paper has something more.

Regards
Sutripta

I am not thinking about how the lower octane fuel is being accommodated by engine.

What i am thinking now is how is the sulphur content not harming the catcon on these skoda cars which are told by the manufacturers to be run on 95 octane.

And why Mercedes asking their CGI engines to be run on 97 octane ?

Now the thing to find out is are skoda cars using some different catcon material to hold nitrogen oxide ? A catcon with material that doesn't react with sulphur ?



I have fool proof documents saying the Mercedes CGI engines need 97 octane min 95 octan fuel. Even the documents stating damage being caused when using lower octane fuel.

[Aroy]

Originally Posted by Neil.Bhujbal

Yes they will surely benefit & yes ones again to 91 & 95 octane fuel having the same sulphur amount. I goofed up on the octane no thing. Octane 97 should be used. At least that's what Mercedes is recommending for CGI engines. I will try to find what has skoda done to make them run on 95 octane. But finding that out might take time.

And here we are taking into consideration octane no not for engine performance & efficiency but for the sulphur content which damages the catcon being used in these engines.

No idea on that,
I am not thinking about how the lower octane fuel is being accommodated by engine.

What i am thinking now is how is the sulphur content not harming the catcon on these skoda cars which are told by the manufacturers to be run on 95 octane.

And why Mercedes asking their CGI engines to be run on 97 octane ?

Now the thing to find out is are skoda cars using some different catcon material to hold nitrogen oxide ? A catcon with material that doesn't react with sulphur ?

I have fool proof documents saying the Mercedes CGI engines need 97 octane min 95 octan fuel. Even the documents stating damage being caused when using lower octane fuel.

The Mercedes top of the line petrol engine uses compression ratio of 11.3:1 (C63AMG), the C200 is 9.3. The higher compression ratio definitely require 97 RON. The lower compression can do with lower RON. May be the Skoda engine has compression ratio on the lower side (< 9?) as it produces much less power - 160, vs 180 for the Mercedes. The capacity is similar 1798 vs 1796 respectively.

Another reason may be as you have stated lower sulfur. Mercedes have been having jamming problems with their high tech ceramic injectors, so high sulfur may be fouling the injectors. As the easiest method of getting less sulfur is to specify 97 Octane, that is it.

[pranavt]

91 RON+MON/2 octane can easily support 11:1 with a low-lift low-duration stock/stock-ish cam. Add a bigger cam and 12.5:1 should be easily doable, especially with onboard knock-sensing and fancy electronics.

At 11.3:1, you could easily run it on pump fuel without any worries of detonation/dieseling. You only need as much advance as the motor needs. More timing does not automatically mean more power.

Not concerned with the dialogue about other pollutants, just thought I'd clear a few things here.

[Neil.Bhujbal]

Originally Posted by Aroy

The Mercedes top of the line petrol engine uses compression ratio of 11.3:1 (C63AMG), the C200 is 9.3. The higher compression ratio definitely require 97 RON. The lower compression can do with lower RON. May be the Skoda engine has compression ratio on the lower side (< 9?) as it produces much less power - 160, vs 180 for the Mercedes. The capacity is similar 1798 vs 1796 respectively.

Another reason may be as you have stated lower sulfur. Mercedes have been having jamming problems with their high tech ceramic injectors, so high sulfur may be fouling the injectors. As the easiest method of getting less sulfur is to specify 97 Octane, that is it.

I am not talking about fuel octane numbers which support high compression engines & which not. Like pranav said high comp engines can run with low octane fuel.And that is what these manufacturer are doing to sell their vehicles in India.

But what my question now is when a car needs 97 octane just for the lower sulphur content so that it doesn't damage the catcon (Mercedes) what are other manufacturers like (skoda) doing that their exhaust are accepting the sulphur content coming from 95 octane ??

In Mercedes the sulphur doesn't do anything to the injectors.If you see the pic i have posted on this page it asks a question. The correct answer is marked in the box. Now have a look at the top left side of the pic it says "STORAGE CATALYTIC CONVERTER".
The question comes under this topic & hence it should be enough to prove that if 97 octane is not used something happens to the catalytic converter.

And this something is it gets damaged but the sulphur. The catcon uses barium carbonate with which the sulphur reacts & loses its capacity to hold the nitrogen oxide.

Now back to the question - what are manufacturers like skoda doing to catch hold the nitrogen oxide produced during lean run mode (stratified mode). What kind of catcon & which material is it made up of ?

[Sutripta]

Hi,
Now that the sulphur/ octane thing has been taken care of, we can move on to the original question.

Originally Posted by Neil.Bhujbal

Now back to the question - what are manufacturers like skoda doing to catch hold the nitrogen oxide produced during lean run mode (stratified mode). What kind of catcon & which material is it made up of ?

Since this is your college project, I'm sure you have done a lot of research on it. So why dont you educate us.

Regards
Sutripta

PS. 97 Oct in our country. Is it supplied by Indian refineries, or is it imported?

[Shivank]

Originally Posted by Neil.Bhujbal

What your saying is quite possible but. But changing the limit of AFR in stratified mode from 1:40 to 1:25 is not going to change the sulphur content in the fuel. So that will still be damaging the catcon.

You might want to check this out.

http://www.autozine.org/technical_sc...#GDI-in-Europe

Originally Posted by Sutripta

Hi,
PS. 97 Oct in our country. Is it supplied by Indian refineries, or is it imported?

Didn't we have the Speed 97 ?

[Sutripta]

Originally Posted by Shivank

Didn't we have the Speed 97 ?

Yes. But where did it come from. What was its sulphur content.

Regards
Sutripta

[antz.bin]

So then, the issue is the high sulphur content not the RON no. which is the same as in EU. Thanks Shivank for that article.

I think BS 5 specifications specify lower Sulphur ratings and the RON no.s will not be changing. So come BS5, The TSi's will start returning better FE. Maybe then even Renault, Nissan and Toyota will have something for all price ranges.

Long Live petrol engines!! (I was actually starting to get worried looking at the advancements in Diesel tech )

But the current specifications for Sulphur content in Petrol are:

BS3 : 150 mg/Kg
BS4 : 50 mg/Kg
Indian Gasoline Specification by Auto Industry in India.
Euro 3 : 150 ppm
Euro 4 : 50 ppm
RIS - Petrol and Diesel Standards - Options

P.S.: mg/Kg == ppm
P.P.S.: Continue debate. This post turned out to be useless.

[Sutripta]

Hi,
I wonder why this interesting thread has stalled. Could I request the OP and others to carry it forward.

One question. What would be the difference in handling NOx between SCSI and SCCI engines? And why?

Regards
Sutripta

[Neil.Bhujbal]

I am trying to find out Skoda Technician who have been to the TSI engine trainings.

Its stuck up there.Even if i find someone he should be enthusiast to really know this information.

That's all i know about it till now. Any further info or interesting find outs will be posted here.

[Sutripta]

@Neil: The MB thing you have quoted/ pasted. It is meant for which country.

Regards
Sutripta