SCRF versus CSF - Are we on the bleeding edge?

Engine, Exhaust, Drivetrain, ECU Faults and Fixes
Trojan
Posts: 66
Joined: Sun Aug 25, 2019 12:57 am

Parkers Guide Sept 2019

Post by Trojan » Sat Sep 28, 2019 9:47 am

Parkers Guide update 16th September 2019 for 20MY Discovery Sport. The following on Running Costs and mpg
* Poor fuel economy overall
* Servicing costs are competitive
* Diesel models now have larger fuel tank

Running costs for the Land Rover Discovery Sport really aren’t anything to get excited about. Official fuel economy for the 250hp petrol that we drove is just 30.5mpg – and on our spirited driving route we saw an average figure in the mid-teens. That’s really poor for a comparatively small SUV, and can probably be accounted for by the car’s vast weight. Range-topping diesel models come in at more than 2 tons, unladen – this car really is a porker.

The diesels provide more palatable running costs, with a combined figure of 39.6mpg for the 240hp model we drove. That’s still not fantastic, though, especially when compared with a car like the Skoda Kodiaq which easily achieves in the mid-40s and beyond.

Those looking for the cheapest running costs should opt for the very entry-level model, which has front-wheel drive and a manual gearbox only. The reward for losing all that capability is a fuel economy figure of 47.8mpg. CO2 emissions for this car go as low as 140g/km, but opting for the range-topping petrol will see this figure skyrocket to 179g/km, despite the mild-hybrid tech.

Reliability

* Previous Discovery Sports were not reliable
* Latest engine tech may fix diesel emissions issues
* Land Rover doesn’t have the greatest reputation

The pre-facelift Land Rover Sport notched up a fairly unenviable reputation for poor reliability. These related in the most part to the diesel emissions systems of the 2.0-litre diesel engine – they failed, contaminating the engine oil and potentially damaging the engine.

Land Rover offered a goodwill gesture to affected owners, but sadly that’s not been the last of the Discovery Sport’s issues. Disappointingly, many owners have reported creaks and rattles from brand new cars, and other issues such as balancer shaft bearing failure. All of these you ought to bear in mind if considering a used Land Rover Discovery Sport – and if buying new, be sure to service the car within the terms of the warranty so that you have some cover should things go wrong.
https://www.parkers.co.uk/land-rover/discovery-sport/review/mpg-running-costs/
Going - 2017 HSE 180 Corris Grey
Coming - BMW X5 45e

Trojan
Posts: 66
Joined: Sun Aug 25, 2019 12:57 am

Re: Newbies Should Read This

Post by Trojan » Sat Sep 28, 2019 10:12 am

Ian_S wrote:
Thu Sep 19, 2019 12:36 pm
Trojan wrote:
Tue Sep 10, 2019 11:35 am
Ah, yes, neck ties. People who know what went on will tell you off the record that Design refused to give Engineering the space they needed to fit the XE DPF behind the transverse Ingenium engine. That decision was, as we know, the single root cause behind all these problems. Now, who was it that made the decisions back then? Who reported to whom? So who ultimately signs off the engineering decisions today?
While it's nice and convenient to blame the evil corporation and the cravat for greed I don't think that is the real reason.

When the Ingenium was being developed for the DS & Evoque, Dieselgate had not yet happened. This I think is important as pre-Dieselgate, most manufacturers were running their engines hotter via the ECU as that produces much less soot, and gives the DPF an easier time. The downside of this is that when run hotter, the engines produce way more NOx. Once they got caught cheating because NOx levels were way higher than they should be (not by small amounts either) then the 'fixes' started to make cars behave like the DS ....

The timing for LR was the worst it could have been, exactly when they were about to launch their new engines. So in order to not get caught up in Dieselgate they have to reconfigure the ECU to be emissions compliant which reduces the engine operating temperature, a double whammy for the DS as now the SCRF is too far away for reduced temps to be at all effective for any kind of passive regeneration, and lower engine temps produce more soot. So with zero passive regeneration to help keep increased soot levels down, DPF's clog more easily and all owners get oil dilution to varying degrees.

The Netflix documentary sums this up perfectly I feel. VW did this to become the no.1 car manufacturer in the world, i.e to gain market share. Where are they now? :) In spite of all the fines, their goal was achieved and they forced all other manufacturers to either quit diesel or copy them to stay competitive. JLR got burned badly.

Unfortunately their soot didn't get burnt at all....
This is far too complicated. The simple explanation been staring us in the face for 2 years ever since JLRP00100, now confirmed by another JLR letter. It is about the heat sink effects of 70 cm of additional pipework.

Fact - If the DS had used the DPF from the XE it would never have suffered from oil dilution, short service intervals and DPF clogging.

The mistake(s) that led to this appalling cock-up came from someone at Jaguar Land Rover, not VW. ;)
Going - 2017 HSE 180 Corris Grey
Coming - BMW X5 45e

Rediscovery
Posts: 111
Joined: Tue Sep 10, 2019 6:39 pm

Re: Newbies Should Read This

Post by Rediscovery » Sat Sep 28, 2019 10:49 am

Trojan wrote:
Sat Sep 28, 2019 10:12 am
This is far too complicated. The simple explanation been staring us in the face for 2 years ever since JLRP00100, now confirmed by another JLR letter. It is about the heat sink effects of 70 cm of additional pipework.

Fact - If the DS had used the DPF from the XE it would never have suffered from oil dilution, short service intervals and DPF clogging.

The mistake(s) that led to this appalling cock-up came from someone at Jaguar Land Rover, not VW. ;)
^ ^ ^ ^ ^ ^ This ^ ^ ^ ^ ^ ^

Look at the new Defender. It has a single DOC-DPF device strapped to the turbo with downstream DEF-SCR. JLR has always known that this is the best arrangement. It's simple and it works. It worked for EU5 in 2012 and it still works for EU6 in 2020.

We have all suffered because SCRF was a Heath-Robinson contraption knocked together in a financial hurricane. All because someone forgot to get their tape measure out....

...or, more likely, they DID measure it but someone else with neckwear insisted that "undiluted design" was more important than "undiluted oil".
17MY SE Tech White

User avatar
Ian_S
Posts: 467
Joined: Thu May 03, 2018 6:53 am
Location: Southern England

Re: Newbies Should Read This

Post by Ian_S » Sat Sep 28, 2019 12:00 pm

Trojan wrote:
Sat Sep 28, 2019 10:12 am

Fact - If the DS had used the DPF from the XE it would never have suffered from oil dilution, short service intervals and DPF clogging.
It's not really fact though, because the other countering fact is that the close mounted DPF used in the XE is there purely because the engine is mounted longitudinally and therefore has the space. The DS does not have the space.

Whether we like it or not, the reason the DS has the architecture it has is because it is based on the Evoque, and therefore any EU6 solution had to fit both cars (and the E-Pace). So there was no clean sheet of paper, and the extra gubbins for NOx removal needed to go somewhere. This is also why the DS was updated so quickly after the Evoque this time as that sharing is quite deep rooted. I'm surprised the E-Pace is not also being updated already.

I'm still going to give the benefit of the doubt to JLR's engineers and don't believe they are incompetent, and that if the engine ran hotter than it does now, that the SCRF solution may have been better. Not perfect, but maybe better enough to allow some passive regeneration.

And again, you can't use the Freelander or other EU5 cars as an example because they all ran their engines much hotter and have all been real-world tested and shown to produce massively more NOx than they should be. That is the direct impact of running the engine hotter, more NOx, less soot, easier time for DPF, more flexibility on where DPF can be, 500 miles instead of 250 between active regens (so less dilution) and less time required to complete one because you generate less soot to start with and passive regens work.

How JLR have handled the problem though is a different matter.... you can fill your boots there. :)
MY2016 HSE TD4 180

ntc
Posts: 110
Joined: Wed Dec 13, 2017 3:34 pm

Re: Newbies Should Read This

Post by ntc » Sat Sep 28, 2019 12:44 pm

Question is with so many leaving LR because of this car can they survive ?
MY 2016.7 Hse Lux 180
Gone should have built it better shame nice car cheap parts fitted from new, expensive dealers :roll:
New Rav4 AWD Dynamic LOVE IT :D

Rediscovery
Posts: 111
Joined: Tue Sep 10, 2019 6:39 pm

Re: Newbies Should Read This

Post by Rediscovery » Sat Sep 28, 2019 9:47 pm

Ian_S wrote:
Sat Sep 28, 2019 12:00 pm
Trojan wrote:
Sat Sep 28, 2019 10:12 am

Fact - If the DS had used the DPF from the XE it would never have suffered from oil dilution, short service intervals and DPF clogging.
It's not really fact though, because the other countering fact is that the close mounted DPF used in the XE is there purely because the engine is mounted longitudinally and therefore has the space. The DS does not have the space.
I disagree. The available evidence does support the hypothetical premise:

If the DS had used the DPF from the XE it would never have suffered from oil dilution, short service intervals and DPF clogging.

But without moving the hard points you are correct to say that it lacks the space. None of the D8 cars have the space required for the Ingenium engine AND a close-coupled DPF. But this didn't stop them trying.

This lack of space (it's just an inch or so) was something that simply got over-looked during an extremely busy period when they were trying to get ten nameplates simultaneously through the EU6 type approval process. It was assumed that, since the Ford/PSA 2.2 Duratorq engine snuggled neatly into the available space in the Evoque and Freelander, not to forget the first 45,000 or so Discovery Sports (UK up to GH516413), together with its close-coupled DPF, then it followed that the transverse AJ200D would fit neatly into the L550 - and into the L538 in due course.

It was a small oversight. But it had enormous consequences.

Two years ago someone claimed to have an engineering source (L550 powertrain design team) that gave them this information via a dealership. Today I can match that with confidential written communications that convey precisely the same information. You can say that all these people are lying, that their memories are unreliable or you can say that I am lying, but otherwise the evidence is what it is. Importantly their evidence is corroborated by JLR documents, as we shall see.
Whether we like it or not, the reason the DS has the architecture it has is because it is based on the Evoque, and therefore any EU6 solution had to fit both cars (and the E-Pace). So there was no clean sheet of paper, and the extra gubbins for NOx removal needed to go somewhere.
Yes, the "extra gubbins" for EU6, that is to say the DEF injector and the 3-way SCR, always go underneath the car because that's the ideal position for them. Look at all the other cars that JLR produce. But JLR's engineers were not idiots - they knew what would happen to soot management if the DPF was also stuck down there in the cold airflow. At some point late on in the development process JLR planned for the L550 to have the DOC-DPF-DEF-SCR architecture. It works best because it places the DOC-DPF pair as close to the engine as possible. In 2015 JLR produced this schematic for the Discovery Sport L550 AJ200 diesel.

Image

This diagram corroborates the accounts of anonymous JLR witnesses. In 2015 at least one part of JLR was still forging ahead with a design that had the exhaust hardware components arranged exactly as they are on the XE. Look at the date on the files: 15th May to 21st July 2015. What other explanation could there be for this document ? In any cogent explanation this document has to be addressed, it cannot be simply swept aside as if it were a forgery or otherwise irrelevant. So what is it describing if not the XE system applied to the DS chassis?

As for the under-floor "gubbins" for NOx reduction, have a look at this diagram. The vehicle in the picture clearly isn't a Jaguar XE. Then look at the accompanying text: Overview The Selective Catalyst Reduction system is an exhaust aftertreatment system used to reduce the nitrogen oxides within the exhaust gas. For this purpose, a specified amount of Diesel Exhaust Fluid (DEF) is injected into the exhaust system, downstream of the DPF... read that again, slowly.... "downstream of the DPF...." Look where the DEF injector (7) is positioned on the downpipe. Think where the DPF has to be located in order to be "upstream" of it. Remember that this is a diagram of a Discovery Sport that you are looking at.

Image
Image
This is also why the DS was updated so quickly after the Evoque this time as that sharing is quite deep rooted. I'm surprised the E-Pace is not also being updated already.
Agreed.
I'm still going to give the benefit of the doubt to JLR's engineers and don't believe they are incompetent, and that if the engine ran hotter than it does now, that the SCRF solution may have been better. Not perfect, but maybe better enough to allow some passive regeneration.
If they'd been able to use the XE DOC-DPF device attached to the turbo as per the provisional workshop manual extract depicted (there's no HP EGR to get in the way on the planned architecture because LP EGR is tapped off after the SCR) the SCRF® would have been unnecessary. No-one is saying that the engineers were incompetent. The suggestion is that they were asked to pull off the impossible. They tried their hardest to create an alternative system but they couldn't make it work with the DPF located so far away from the engine. Physics. Chemistry, Thermodynamics. Talented engineers proved no match for the immutable laws of nature,

What is suggested is that senior executives knew that there were massive risks of failure with the "alternative exhaust" project and that they pushed sales and marketing plans forward against the advice of their engineers. Where are the people concerned today? It's an excellent question. They are probably reading this. If they disagree with the views expressed they are at liberty to offer their alternative evidence. If this is the wrong interpretation, why doesn't JLR correct the record?

We could also legitimately ask why JLR used the L550 production vehicle as a test platform for coatings that were still at the prototype stage of development. A year after the Discovery Sport Ingenium was launched, the coatings manufacturer gave a presentation in America which ended with speculative statements about possible ways to improve known shortcomings of the SCRF® system. This happened a year after it was being fitted to production cars? I wish I was joking. What shortcomings had they identified? Well how about this, for starters. "The SCRF® catalyst can be fully regenerated (95%) in ~30 mins at 600°C". That was the state of play for SCRF® in 2016, according to the manufacturer.

How good is 95% regeneration in approximately 30 minutes? It is rubbish. It compares to a full - i.e.100% - regeneration at 600°C in 20 minutes for a catalysed soot filter (CSF) - i.e. like the DPF device used on the XE. So a 50% longer burn is needed with a SCRF® compared to a CSF and it still can't clear the filter completely. This would no doubt have been explained to the management in words of one syllable when the decisions to use it in the L550 and L538 were being taken. But still management didn't catch on. Maybe the chemists at the party were more convincing in persuading management that this new SCRF® technology could break the laws of nature. Maybe they said the engineers were "stuck in the past". Who knows? The engineers were over-ruled is all we can say.
And again, you can't use the Freelander or other EU5 cars as an example because they all ran their engines much hotter and have all been real-world tested and shown to produce massively more NOx than they should be. That is the direct impact of running the engine hotter, more NOx, less soot, easier time for DPF, more flexibility on where DPF can be, 500 miles instead of 250 between active regens (so less dilution) and less time required to complete one because you generate less soot to start with and passive regens work.
All of those obstacles were overcome with the XE exhaust. It uses minimal post injection for DPF regeneration and the car makes it comfortably to the extended service intervals The DPF's are not known for clogging or failing. If the XE exhaust architecture had been fitted to the L550 - as JLR documentation shows clearly was still intended between 15th May and 21st July 2015 - then it, too might have performed flawlessly and in doing so fulfilled every one of the claims made for it in the brochure.

The sickening part of this is not that the Discovery Sport failed to live up to the promises contained in the brochure. It's that when it didn't (for understandable reasons), instead of taking responsibility and putting things right, this miserable little company then spent four years blaming its customers' "driving style" while using every trick in the book to hide what it had done.

Perhaps the Serious Fraud Office ought to be reading this as well.

Published: 21-Jul-2015
Exhaust System - INGENIUM I4 2.0L Diesel - Selective Catalyst Reduction
Description and Operation
Exhaust system Selective Catalyst Reduction.pdf
(283.48 KiB) Downloaded 37 times
17MY SE Tech White

Rediscovery
Posts: 111
Joined: Tue Sep 10, 2019 6:39 pm

Re: Newbies Should Read This

Post by Rediscovery » Sat Sep 28, 2019 10:41 pm

The first DS with Ingenium and SCRF® shipped in September 2015. Here's a taste of the evidence that SCRF® was still undergoing significant development in 2016. Our 16MY and 17MY diesels were, in effect, JLR's test platforms.

summary0.PNG

summary.PNG

summary1.PNG

summary2.PNG

2016CLEERS_Cumaranatunge.pdf
(786.13 KiB) Downloaded 29 times
17MY SE Tech White

User avatar
Ian_S
Posts: 467
Joined: Thu May 03, 2018 6:53 am
Location: Southern England

Re: Newbies Should Read This

Post by Ian_S » Sun Sep 29, 2019 10:41 am

@Resdiscovery ...

Having worked for several large corporations, documentation is usually written by technical writing teams, and the non-specific block diagram is likely to be nothing more than a simple copy and paste job on the grounds that at the block level, it's largely correct. For the XE you could put a further box round the DOC and DPF and for the DS you would put the extra box round the DPF and. SCR elements instead. The document for the 'DPF' operation uses the block diagram. The document for the SCR system, or NOx after-treatment system uses diagrams showing the placement of actual components in the DS itself.

You could start to get really pedantic here and say well both documents are in effect in-accurate because there is neither a separate DPF, OR, a separate SCR system, they are combined in an SCRF, which is identical in shape to the component highlighted in red under the DS floor pan. I doubt very much that the XE SCR system component looks like the DS SCRF. And the main reason they will still discuss these high level systems (DPF and SCR) separately is because that's how everyone understands them. Everyone here still talks about DPF replacement, but really it's an SCRF replacement. (Part of the reason it'll be more expensive too.)

So personally I don't see that either of those documents show any clear evidence of JLR having developed a close coupled DOC-DPF solution and changed their mind at the last minute. It seems more likely that someone simply re-used a block diagram, and someone else wrote the NOx after treatment part later showing the actual components that were being used. Yes in 2013 the original intention may well have been to use a DOC-DPF, but I bet they found pretty quickly that it didn't fit the Evoque, and I also bet that everyone from design and engineering wanted to share the same system between the Evoque, DS and E-Pace if the latter was on the drawing board at that stage. All guesses of course ...

The more interesting things in what you've posted are the lack of efficiency in the SCRF in cleaning the soot, and the fact that it never seems to actually manage 100%. Also not much mention of any passive cleaning. Another interesting question for an SCRF is can you clean the ash from it like you can a more standard DPF? If you can't then that implies once it's full of ash, it's a new SCRF.... which as we know is expensive. Not great news for long-term owners and also does the absence of 100% soot burning even after 30 mins mean that the soot filter part of the SCRF has a shorter working life than a seperate DOC-DPF solution?
MY2016 HSE TD4 180

Rediscovery
Posts: 111
Joined: Tue Sep 10, 2019 6:39 pm

Re: Newbies Should Read This

Post by Rediscovery » Sun Sep 29, 2019 12:16 pm

Ian_S wrote:
Sun Sep 29, 2019 10:41 am
@Resdiscovery ...

Having worked for several large corporations, documentation is usually written by technical writing teams, and the non-specific block diagram is likely to be nothing more than a simple copy and paste job on the grounds that at the block level, it's largely correct. For the XE you could put a further box round the DOC and DPF and for the DS you would put the extra box round the DPF and. SCR elements instead. The document for the 'DPF' operation uses the block diagram. The document for the SCR system, or NOx after-treatment system uses diagrams showing the placement of actual components in the DS itself.

You could start to get really pedantic here and say well both documents are in effect in-accurate because there is neither a separate DPF, OR, a separate SCR system, they are combined in an SCRF, which is identical in shape to the component highlighted in red under the DS floor pan. I doubt very much that the XE SCR system component looks like the DS SCRF. And the main reason they will still discuss these high level systems (DPF and SCR) separately is because that's how everyone understands them. Everyone here still talks about DPF replacement, but really it's an SCRF replacement. (Part of the reason it'll be more expensive too.)

So personally I don't see that either of those documents show any clear evidence of JLR having developed a close coupled DOC-DPF solution and changed their mind at the last minute. It seems more likely that someone simply re-used a block diagram, and someone else wrote the NOx after treatment part later showing the actual components that were being used. Yes in 2013 the original intention may well have been to use a DOC-DPF, but I bet they found pretty quickly that it didn't fit the Evoque, and I also bet that everyone from design and engineering wanted to share the same system between the Evoque, DS and E-Pace if the latter was on the drawing board at that stage. All guesses of course ...

The more interesting things in what you've posted are the lack of efficiency in the SCRF in cleaning the soot, and the fact that it never seems to actually manage 100%. Also not much mention of any passive cleaning. Another interesting question for an SCRF is can you clean the ash from it like you can a more standard DPF? If you can't then that implies once it's full of ash, it's a new SCRF.... which as we know is expensive. Not great news for long-term owners and also does the absence of 100% soot burning even after 30 mins mean that the soot filter part of the SCRF has a shorter working life than a seperate DOC-DPF solution?
Image
Image

This is not a block diagram. It is a CAD/CAM extract dated 21st July 2015. The vehicle is clearly a L550 Discovery Sport. We can't see the DPF but we can see the DEF injection point (7) and we can all read the words.

The Selective Catalyst Reduction system is an exhaust aftertreatment system used to reduce the nitrogen oxides within the exhaust gas. For this purpose, a specified amount of Diesel Exhaust Fluid (DEF) is injected into the exhaust system, downstream of the DPF.

You presumably understand the meaning of "downstream" as well as I do. It means that in this 21st July 2015 drawing, the DPF (it is clearly visible adjacent to the bulkhead in another drawing that I can post) is above the injector, close to the engine. DOC-DPF-DEF-SCR. These words and pictures match what engineers have said happened. Why are there no words and pictures describing SCRF to the same level of detail? Perhaps because it was only invented in 2014 and was still basically a prototype when these drawings were produced?

As JM's presentation shows, this was still novel technology that was incapable, more than one year after the events we are debating, of completing a full regeneration inside 30 minutes. So JLR would have known this in 2015, wouldn't they? This is the pincer moment. Whatever the "preferred" choice of architecture in July-August 2015 JLR had left itself in an impossible position because, having denied the powertrain engineers the space they needed, it found itself having to choose between:

1) a workable design that met the spec but didn't fit without the risk of setting fire to the car;
2) prototype hardware that could be made to fit but didn't work according to spec (and never would), or
3) suspending L550 production until there was a design that both fitted and worked.

For purely commercial reasons JLR decided it was better to go with option 2, hide the problem for as long as possible (normally 2 years) and then blame diesel dilution and clogged DPFs on the driving style of anyone who had the temerity to challenge the quality of a JLR product.

Not pretty.
17MY SE Tech White

User avatar
Ian_S
Posts: 467
Joined: Thu May 03, 2018 6:53 am
Location: Southern England

DOC, DPF and SCR ....

Post by Ian_S » Sun Sep 29, 2019 7:10 pm

Rediscovery wrote:
Sun Sep 29, 2019 12:16 pm
This is not a block diagram. It is a CAD/CAM extract dated 21st July 2015. The vehicle is clearly a L550 Discovery Sport. We can't see the DPF but we can see the DEF injection point (7) and we can all read the words.
Come on ... :D

Clearly by block diagram I meant the first diagram in your initial post copied below... Let's call this Diagram 1.

Image

The diagram you quote in the post before this one, which as you say is clearly some kind of CAD export comes from the SAME document, so let's call that diagram 2. As I Previously stated, in diagram 1, if we are going to take it as gospel, it is in fact incorrect for either the XE or any close coupled DOC-DPF arrangement (DOC is item 10, DPF is obviously item 9) as these tend to be in the same box. Likewise it's also incorrect for what is in the DS, Evoque etc. as in that arrangement 6, the SCR and 9, the DPF are in the same under-body component and the DOC (10) is close mounted to the engine.

Diagram one is clearly a generic block or schematic on the overall components in a system and their rough interaction. I can't agree that this is enough to conclude they were still pursuing a close coupled DOC-DPF unit as per the XE. To further illustrate you can easily find the following diagram also from July 2015 on the 'DPF'... Let's call this diagram 3.

DPF_diagram_03.jpg

Looking at both diagram 2 and 3 we can see quite clearly that the same component, the SCRF (combined SCR and DPF function), is described as either the SCR (Item 8, diag 2) or DPF (item 4, diag 3) depending on whether you are looking at the DPF system document or the SCR system document. It is in the same place and the same shape on both the DS CAD drawings.

So again I stand by what I said that if we want to be really picky, both CAD diagram parts lists are incorrect, and we shouldn't refer to a DPF or SCR on the DS, but instead SCRF which combines the two. For me the simple explanation is that diag 1 is a generic schematic probably used in many places and that diag 2 and diag 3 are used differently to highlight ancillary components that apply only to that function and also because people understand what a DPF is...

None of which is trying to refute anything you've said about the SCRF operation and the clear demonstration of how in-efficient it is. That information is both very useful and dis-heartening in equal measure.

We can only hope if this architecture is still present on the new DS and Evoque, that SCRF technology has improved massively since 2015-16 and that it has solved some of the issues. Else this nightmare will persist for many. Can't see who wins there.
MY2016 HSE TD4 180

Post Reply