SCRF versus CSF - Are we on the bleeding edge?

Engine, Exhaust, Drivetrain, ECU Faults and Fixes
VeryDiscoSport
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by VeryDiscoSport » Thu Nov 23, 2017 8:44 pm

chicken george wrote:
Thu Nov 23, 2017 1:05 pm
When do I get my apology???

Not until hell freezes over is one phrase that immediately sprang to mind. I was told by an extremely reliable source who got it from an actual design engineer from Jaguar Land Rover that the pipework architecture is too long on the DS for the chosen exhaust hardware to work properly. Everything I have discovered bears out the statements that were repeated to me: having selected this particular chemistry set, it was found that it won't all fit as designed into the available space and has to be spread out.

This is a quote from Johnson Matthey's Chris Morgan writing in 2014 when SCRF was just emerging commercially:

Due to the thermal mass of the CSF (required to withstand uncontrolled soot regeneration) and heat losses from the exhaust pipe in the urea mixing zone in front of the SCR, it can take many minutes of city driving before the SCR warms up sufficiently to provide high levels of conversion efficiency. An elegant solution is to integrate the SCR coating onto the particulate filter (10), thus enabling the SCR coating to heat up and become active more quickly, whilst also improving the compactness of the system (Figure 2). Such SCR coated on filter (SCRF®) technologies are now in series production – another world first for Johnson Matthey, Royston.


It could all work so beautifully - were it not for those two hulking great pieces of pipework which turn a great Compact Design Goal into a Spread-out installation that then requires higher than expected amounts of post-injection because a) the DOC doesn't get hot enough to do anything in normal driving and b) the SCRF is too far back to heat up quickly and efficiently as the patent holder intended.


THE VISION

Compact SCRF Design.JPG


THE REALITY

Non-compact SCRF.JPG

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Barnsh
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by Barnsh » Thu Nov 23, 2017 9:29 pm

That's exactly the issue VDS, in pretty much the same explanation from DEKRA.

Tinkering with software adjustments may bring some small benefits, but as per the JLR PDF the above picture is exactly the "hardware and architecture differences " mentioned .

The only complete remedy is a redesign to get the componants to operate correctly. The hard part is that this has to be achieved without compromise to the internal layout of the DS which is class leading and we all love.

Some definate head scratching will be happening in the emissions department of JLR without doubt, maybe that's why they advertised to fill many positions with emissions engineers a few weeks back.

Especially when the new emissions tests as mentioned in the VED tax rise make the Discovery D5 look so poor with Compliance.

I don't think there would have been so many vociferous conversations on this forum if JLR had achieved an average of 15-16k for servicing on the DS, but to achieve an average of 9/10k out of a planned 21k is just plain wrong and madness. I would hazard a guess some even more vociferous conversations took place at JLR when these early oil changes started appearing across the affected vehicles.

It would have been better if JLR had just said sorry instead of trying to blame everyone's driving style which only antagonises and disappoints owners. The free oil is just a stop gap to stem some complaints and placate owners, it is also a vast expense for a company to accept if no "full" fix is found.
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chicken george
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by chicken george » Thu Nov 23, 2017 11:58 pm

Seems Audi screwed up the Q& as well then :roll:

audi-q7-adblue-tank.jpg

As well as many other manufacturers

generic pics and home made alterations dont prove anything

particulate filter too cold is a generic explanation for poor dpf performance, well known by all manufacturers,

I will say again the DS does not have a close coupled design, the pipe work length is not the issue, Infact the length between the doc and scrf is needed to allow def infection and proper swirling/mixing of the def before it reaches the scrf.
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by VeryDiscoSport » Fri Nov 24, 2017 12:24 am

Barnsh wrote:
Thu Nov 23, 2017 9:29 pm

I don't think there would have been so many vociferous conversations on this forum if JLR had achieved an average of 15-16k for servicing on the DS, but to achieve an average of 9/10k out of a planned 21k is just plain wrong and madness.

I would hazard a guess some even more vociferous conversations took place at JLR when these early oil changes started appearing across the affected vehicles.

It would have been better if JLR had just said sorry instead of trying to blame everyone's driving style which only antagonises and disappoints owners. The free oil is just a stop gap to stem some complaints and placate owners, it is also a vast expense for a company to accept if no "full" fix is found.

The engineer said they pleaded the case for 12K or 16K before launch but were told it was a done deal. So they went to market with a brochure that contained misleading statements in order to make the cars appear more attractive in respect of servicing intervals and we know from the conversations reported to me by my source that at least one person in JLR management knew that the brochure was misleading at the time. The thing is that once you've told the first lie you have to keep on lying in order to cover up the first one. But just how orchestrated was the deception between June 2016 and July 2017 when another engineer gave me a hard copy of JLRP00100 and it all started to unravel? It would be interesting to hear a few dealers declare for the record where the stories of "service interval set for the old engine", "problem with the phone app", "bad batch of oil", "incorrect service interval", "software upgrade coming soon", "software glitch, keep driving up to 21K miles" first came from.

I mean - they are all lies, right? So, did the dealers just instinctively improvise these erroneous explanations? Or were they told what to say to concerned customers by CRC? The first round of untruths had quite a good run based on the posts on the forum and was still going well in July 2017, even a couple of weeks ago there are fresh reports here and on other forums with dealers nonchalantly dismissing the relevance of the Service Message. But when did "driving style" first appear? A cursory trawl through the posts shows it was first being linked with early service messages around March/April 2017 and that one also had a good run until very recently. With some co-ordinated and dedicated "amateur" sleuthing I think that we might have finally forced the management to swallow the truth potion.

Honest John emailed me today after I reported the successful rejection. He said that JLR now admits that the DPF will remain too cold to passively regenerate when the car is driven short distances and that they will also change the oil service schedule to a more sensible one. Having seen the entire text of the four page letter I received on 24th October he finished by noting that "because it has gone to such great lengths in its replies to you, I'd suggest that your detailed complaint influenced the company." Coming from the straight guy himself, that's not bad for somebody who has been openly accused of peddling "fake news".
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by VeryDiscoSport » Fri Nov 24, 2017 12:41 am

chicken george wrote:
Thu Nov 23, 2017 11:58 pm
Seems Audi screwed up the Q& as well then :roll:
audi-q7-adblue-tank.jpg

As well as many other manufacturers

generic pics and home made alterations dont prove anything

particulate filter too cold is a generic explanation for poor dpf performance, well known by all manufacturers,

I will say again the DS does not have a close coupled design, the pipe work length is not the issue, Infact the length between the doc and scrf is needed to allow def infection and proper swirling/mixing of the def before it reaches the scrf.

No-one is trying to prove anything, this is just a forum for exchange of information and ideas. But, whilst we are being mutually critical, the diagram you have reproduced is from an altogether different system architecture. There no shortage of data available about SCRF, please go and please read what Chris Morgan and others say about the strengths and weakness of their system versus the competing ones. There's an excellent powerpoint on here somewhere that shows how slowly it removes soot compared to other systems, but conversely how good it is at NOx reduction - in the right conditions.
2017 DS L-550 2.0 SE Tech 150 6 SPD (Rejected per CRA 2015) :(
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by Barnsh » Fri Nov 24, 2017 1:02 am

I hear what your saying CG, all manufacturers do have an issue with temperature. It's one of the critical items in the process to be efficient.

This is why most new systems including the XE/XF ( I use this example as that is what JLR used on their PDF, I also use this example as it has the same 2.0L ingenium engine).now have close(r) coupled systems.

Comparing an audi system is throwing another different componants and design in the mix. And as you can see in the diagram you showed DEF is added after a DPF. Different engine different amount of soot.

Do you not think if space had been available that they would have used the same system on the DS as the working XE/XF ? ( maybe jag and Land Rover don't communicate).
But:
Do you not think they would have used the same system on the 30L D5 as the working in line mounted 2.0L D5? Only difference is space available.

For an identical 2.0L ingenium engine the only difference in emmissions system is layout , componants and space available. Therefore it's a backward step to add distance so that the well known temperature issue is exacerbated. The lack of space to me has forced the componants and architecture into that position of the old issue of lack of temperature.

The XE/XF/D5 2.0L ingenium doesn't need an early service to the extent the DS and other affected vehicles do.

The longer pipe just acts as a heat sink.

Your right many manufacturers have screwed up over this in the past, but most have overcome it too, or at least in the past couple of years improved it. JLR dropped the ball somewhere in the design stages of these vehicles, they for sure didn't do it deliberately.
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by Barnsh » Fri Nov 24, 2017 1:17 am

A good read on design all be it for a mine
"
Thermal insulation of exhaust pipes and filters, where possible, was found to be effective in improving DPF performances. The length of exhaust manifolds and number of bends were minimized for optimum performance."

https://www.cdc.gov/niosh/mining/userfi ... /dpoeo.pdf
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MY17 HSE 180 gone
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My16 DS 180 ~ rejected :oops:


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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by Chippy » Fri Nov 24, 2017 6:02 am

I think it’s high time that everyone involved in this discussion simply agrees to disagree and bury this never ending story.

All this “discussion” isn’t really going to change anything even if we think it will. JLR know about the situation, it’s not right everyone agrees on that and it will get sorted.

Leave it up to them and accept what we’ve got or get rid of it.

If you disagree with me that’s no problem but please don’t reply “If you don’t like it just ignore the topic”
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Re: SCRF versus CSF - Are we on the bleeding edge?

Post by simon » Fri Nov 24, 2017 7:46 am

Agree Chippy.
There are far better forums to be welcomed at than this one that locks threads because certain members can’t take a bit of criticism :roll:


weemark

Re: SCRF versus CSF - Are we on the bleeding edge?

Post by weemark » Fri Nov 24, 2017 7:53 am

And me


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