There is an interesting (but somewhat technical) description of DLC on Wiki. I thought this was interesting:
"The same internal stress that benefits the hardness of DLC materials makes it difficult to bond such coatings to the substrates to be protected. The internal stresses try to "pop" the DLC coatings off of the underlying samples. This challenging downside of extreme hardness is answered in several ways, depending upon the particular "art" of the production process."
Wiki
But Bosch engineers should be adept at solving these sort of problems.
Glendale Titanium 29E34TS fifth wheel
2012 Ford F-350 4WD Lariat 6.7L
PullRite OE Series Super5th 18K
Superbumper
Ford is also trying to throw Bosch under the bus (maybe deservedly) stating that they buy the pump as a black box from bosch and don't do any testing on it.Ford even puts the scar chart in it's response. Not sure what the point is there, as it would in my eyes point the finger at ford.
Same goes for fords customers. Ford states that they have been warned about all the precautions their customers need to take.
To be fair to Ford, I sincerely believe that Bosch told them very little (and they know little) about the magic pixie dust sprinkled on the CP 4 pump to make it both cheaper to build and handle higher pressures.
I do believe Ford saying they do no testing.
Given how antagonistic Ford (or any major car maker) is with their suppliers, there is very little sharing of knowhow and IP.
Bosch keeps cards close to vest to protect their margins.
In any case, the buck stops with Ford, not Bosch when it comes to the customer.
New hypothesis...based in large part in the philosophies of design for industrial
controls vs consumer stuff
A few things mentioned rung my bell...
Is it true that the same pump is used on the 'cars' in Europe? Same design/architecture
The basic design is identical, but the Ford documents to NHTSA suggest that the North American version is engineered to accept lower lubricity fuel.
That suggest a change in the coating, but mechanicals are identical AFAIK / AFAI Can See. Next questions are whether there are common parts between them.
Then since common, my assumption, then are the stresses of two cylinders
within their original spec?
another oxymoron for me, is that diamond is the slickest and non-stick
known to mankind....meaning that lube will NOT film on it...so what
is breaking down?
NewsW comment in Green:
Note it is Diamond LIKE Carbon Coating, but NOT Diamond per se.
or also the same one for the full sized pickups over here?
The big change is the number of pistons / cylinders it has.
Larger volume needed for V8s get 2 cylinders vs. 1 for the passenger cars.
What is the specification for the common rail fuel system? PSI at some GPH and
assume some level of design margin
Published specs are for a max pressure of 2,000 bars, do not have the actual cc at rated pressure handy.... though individual car makers / implementers can use less by setting the pressure relief valve lower.
Assume that the PSI requirements goes up with RPMs, as does the GPH go up with
higher RPMs, right?
Up to the maximum rated capacity of the pump! does this mean they are at the max with no margin?
Only Bosch engineers with the data can answer this one.
I stress I have no visibility into what must be very closely held, proprietary data.
Then if it is the same one, so much margin is in there for the cars, and/or so
little for diesels twice or more in displacement
No doubt the 6.7 with its max HP / Torque is pushing the volumes from the 2 cylinder version to the maximum.
Also, everyone is stuck in a rathole and suggest climbing out to see the whole
picture. Maybe a 30,000 foot view.
I think using a piston is questionable and would have sent the designers back
and report on gear pumps vs whatever specification they had on the table at the
CDR's
They are bandaiding that very small contact issue on the cam with exotic stuff
Believe, based on Bosch published technical papers at the SAE, that the coating is used on both the cam and other contact surfaces like the piston and bore. Application like the piston and bore is a good one for DLC, but
small contact area/high PSI like the follower on cam is questionable
for DLC or any brittle material. Worse if shock loads.
Still questioning why or their reasoning of the chrome. Again, I'd
have made the cam and shaft out of 4160, case hardened to some depth
to withstand the PSI without deformation. Then coat, if at all, the
DLC. To me, sounding like a common part 'built' up with chrome
We don't know what coatings are used where.
DLCs come in many different flavors, and they are quite different in properties.
It is not clear that the same coating was used on the piston / cylinder vs. the cam surfaces.
Normally it would be to increase the surface area. Wider roller follower on
the cam, which will also need to be widened....etc
Bosch happily bragged that they reduced costs and raised pressure on the CP 4 vs CP 3.
Maybe you are onto something.... they put a lot of faith in whatever coatings they used to allow for a major design change for less mechanical complexity, not more.
again, my experience with diamond is that it is brittle and
must have lots of surface area. Point loading is a very, very bad
application
Issue here is ... you are talking about a major redesign / fundamentally different pump to handle the lubricity / pressures.
They chose to do it with coating changes alone.
Or a better way would be a journal bearing like a ICE crank shaft with lots of
surface area.
BUT...that costs more and maybe they didn't want to change the basis design that
they used for us over here.
That would remove the spring that returns the piston during the down stroke. The
spring loading adds to the PSI loading on the cam (piston, follower).
With a lower PSI on the cam, now a crank, would they need these exotic
coatings?
Not too sure you can do it without the coatings, given that the coated parts have lifespans measured in not single, but often 10X or more life (at least when it is working as expected.)
Open question here... have we reached the economic point of no return with higher injection pressures?
good question and is in line with mine on whether a different
type of pump would make a difference
Concur --- and it is my wish that both Ford and Bosch engineers see some of these posts!
Back into the rat hole:
As to the chrome plating...chrome is known to have micro cracks/fissures/etc
The junctions between the base and chrome also a potential issue and
that boils down to the fastidiousness of the production process(es).
Ditto the exotic coatings. Also, chrome or any plated coating for that
matter, needs to be ground down to whatever RMS spec'd. Am not familiar
with DLS, but do know that some of the other diamond processes introduces
heat...does that play with the chrome and base?
When you do the coating, part and parcel of the process is extremely careful surface preparation of the base part, and then inspection with high tech inspection tools, and only those that pass are off to the base coat.. then DLC coating.
After it is done --- it is inspected again real carefully.
The complexity and difficulty of controlling the process means:
The part is very hard for a 3rd party to clone (if at all).
Nearly no room for aftermarket modders not equipped with a fortune in high tech coating tools to do anything with it. didn't you say they bragged about reduced costing a few paragraphs
back?...this is in the other direction...wonder if Bosch got lost
in their own game here
More later when I have time
Bosch has taken this stuff to a new level compared to the good old days with gears, metals etc.
You can always tell Bosch is a pioneer in this business....
They are lying face down... with arrows sticking out of their back! know this path, but missing are their test mule info...are
their buyers now those test mules?
Good old pumps did the job, albeit a bit bigger...concrete cutting, etc
and higher PSI's than this...though mostly continuous flow, not squirts...
One new thought based on old info that just doesn't feel right is that
DLC and the whole family of diamond coatings are all non-stick and
inert...therefore, why is it being attacked by chemicals if it is
inert?
Conventional wisdom right up to 2008 THOUGHT DLCs are quite inert, conduct heat real well, and is ideal for many applications.
Unfortunately, we now know better --- organic amines will damage the coating.
Again, the debris would tell lots, but like you said...must be virginal
debris not mixed in with resultant failure material
The problem is not easy to solve... suspect more than a few hundred engineering hours at Bosch and Ford has been spent on this issue.
Unfortunately, we now know better --- organic amines will damage the coating.
Sorry...what I meant was why do they have to have a specialized lubrication
fluid on top of an already known slippery, low co-efficient, inert material
I don't know anything about amines, till you pointed it out and is
now on my reading material list
Why have a lube on top of a low co-efficient material says to me, that
they are shooting at the wrong target or trying to solve whatever they
'think' the problem but missed. As they are shooting at the wrong
target and created another problem
That is what meant by a rat-hole and the need to climb out and see
the bigger picture
I've seen design teams directed by bean counter management down these
rat-holes trying to save their bottom line...only to create a bigger
problem(s) and cost more money
In asking why is the stuff coming apart, they miss the real why...
Why is there such a high PSI in 'that' area and then wonder if they
have ID'd the right area?
I used to direct my teams to use the leveraged model and use the corp
parts bin....but....also knew to watch out for a Rube Goldberg resultant
and the NIH factor
Adding a second cylinder sounds like a very good leveraged model, but
are the other common components up to the 'new' specification that
they did not have on their design plate? Why noodling a different
pump type to scaling the whole thing both larger and better base materials
so that the extremely expensive processes/materials that they ended
up using might not be needed.
Designers LOVE whizzy bang stuff...I still do, but there needs
to be sanity checks (CDR's) without bean counter mentality (fiduciary
responsibility is a requirement, but not the end all)
Unfortunately, we now know better --- organic amines will damage the coating.
Sorry...what I meant was why do they have to have a specialized lubrication
fluid on top of an already known slippery, low co-efficient, inert material
I don't know anything about amines, till you pointed it out and is
now on my reading material list
Why have a lube on top of a low co-efficient material says to me, that
they are shooting at the wrong target or trying to solve whatever they
'think' the problem but missed. As they are shooting at the wrong
target and created another problem
The documentation shows organic amines will damage DLC coatings... the question is.. what else normally found in diesel fuel and common additives will?
Is it conceivable that breakdown products of diesel fuel under 2,000bars and 150C or higher can include organic amines?
Could it be in the numerous additives sold to make diesel fuel better either at retail, or sold to biodiesel or refinery or distributors of diesel fuel?
Could it be in things like ATF, 2 stroke oil, or normal lubricating oil often added to diesel fuel by end users, OR as a contaminant in diesel fuel (either deliberately put there or otherwise).
Point is --- reactivity of stuff the Bosch CP 4 pump coatings at the temperatures / pressures they operate in...
Did the engineers factor it in enough at the time of design and validation?
Ford is also trying to throw Bosch under the bus (maybe deservedly) stating that they buy the pump as a black box from bosch and don't do any testing on it.Ford even puts the scar chart in it's response. Not sure what the point is there, as it would in my eyes point the finger at ford.
Same goes for fords customers. Ford states that they have been warned about all the precautions their customers need to take.
To be fair to Ford, I sincerely believe that Bosch told them very little (and they know little) about the magic pixie dust sprinkled on the CP 4 pump to make it both cheaper to build and handle higher pressures.
I do believe Ford saying they do no testing.
Given how antagonistic Ford (or any major car maker) is with their suppliers, there is very little sharing of knowhow and IP.
Bosch keeps cards close to vest to protect their margins.
In any case, the buck stops with Ford, not Bosch when it comes to the customer.
Very interesting technical discussion.
However may I say "Here we go again"
Although the 6.7L engine is built by Ford they have a major system supplier in Bosch that they are buying an end to end pre-packaged sealed solution from in the fueling system and as a consumer I am very concerned that the relationship between Ford and Bosch will go the same route that Navistar and Ford end up going with the 6 liter engine.
Due to Ford's warranty denials the dirty laundry between Ford and Bosch regarding the technical challenges is getting plastered around the industry and consumer space while GM is managing their image much more positively by apparently not denying any warranty claims so far.
Ford needs an image management team that has the clout to make Ford's senior management understand the unnecessary damage they are doing to their reputation with these denials while the industry determines the underlying cause and affect and engineers a complete solution.
Maybe I should go on record in supporting Ford for greatly tightening warranty claim administration.
Over the years, I have seen Ford (and Navistar) being mugged by their customers, dealers, techs, and many others.
Modifications that are responsible for failure of Ford / Navistar engines were flogged to customers with abandon, with out and out lies that Ford will not know / find out that the mods probably did a great deal to cause failures that Ford paid the bills for.
The problem is, greatly tightening warranty --- while necessary --- also means a few cases got through that Ford should have paid attention to.
Like the CP 4.2 HPFP failures that were unexplained.
Ford is also trying to throw Bosch under the bus (maybe deservedly) stating that they buy the pump as a black box from bosch and don't do any testing on it.Ford even puts the scar chart in it's response. Not sure what the point is there, as it would in my eyes point the finger at ford.
Same goes for fords customers. Ford states that they have been warned about all the precautions their customers need to take.
To be fair to Ford, I sincerely believe that Bosch told them very little (and they know little) about the magic pixie dust sprinkled on the CP 4 pump to make it both cheaper to build and handle higher pressures.
I do believe Ford saying they do no testing.
Given how antagonistic Ford (or any major car maker) is with their suppliers, there is very little sharing of knowhow and IP.
Bosch keeps cards close to vest to protect their margins.
In any case, the buck stops with Ford, not Bosch when it comes to the customer.
Very interesting technical discussion.
However may I say "Here we go again"
Although the 6.7L engine is built by Ford they have a major system supplier in Bosch that they are buying an end to end pre-packaged sealed solution from in the fueling system and as a consumer I am very concerned that the relationship between Ford and Bosch will go the same route that Navistar and Ford end up going with the 6 liter engine.
Due to Ford's warranty denials the dirty laundry between Ford and Bosch regarding the technical challenges is getting plastered around the industry and consumer space while GM is managing their image much more positively by apparently not denying any warranty claims so far.
Ford needs an image management team that has the clout to make Ford's senior management understand the unnecessary damage they are doing to their reputation with these denials while the industry determines the underlying cause and affect and engineers a complete solution.
Damn...somebody gets the kewpie doll...Great post
Regards
Ricatic
Debbie and Savannah the Wonderdachsund
2009 Big Horn 3055RL
2006 Chevrolet Silverado 3500 Dually LTX with the Gold Standard LBZ Engine and Allison Transmission
2011 F350 Lariat SRW CC SB 4WD 6.7 Diesel POS Gone Bye Bye
NewsW wrote: Maybe I should go on record in supporting Ford for greatly tightening warranty claim administration.
Over the years, I have seen Ford (and Navistar) being mugged by their customers, dealers, techs, and many others.
Modifications that are responsible for failure of Ford / Navistar engines were flogged to customers with abandon, with out and out lies that Ford will not know / find out that the mods probably did a great deal to cause failures that Ford paid the bills for.
The problem is, greatly tightening warranty --- while necessary --- also means a few cases got through that Ford should have paid attention to.
Like the CP 4.2 HPFP failures that were unexplained.
and I am on record supporting Ford's attempts to control consumer warranty fraud. The problem is, as you stated, unmodified trucks are getting the "modified truck" treatment...
GM is treating their customers like they appreciate the business...Ford is screwing their customers...
I'm not an engineer by training, so for the engineers participating in this thread....
I read somewhere in my obsessive googling on this topic that the HPFP failures may in some way be related to low input pressure that is caused by the primary fuel pump. Is that at all a possibility?
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