Using filters to contain HFPF failures?

[turbocharged798]

First off, I am not sure where to post this because the CR engine is being used on several platforms now but this section seems to have the most HPFP discussion.

I have been following 2microns thread on retrofitting a CP3 pump:

http://forums.tdiclub.com/showthread.php?t=367804

Don't get me wrong, I absolutely applaud his work and think he will be quite successful. It just my personal opinion is that its a bit too involved and complex to be mainstream.

To me, if you could just contain the fragments when the HPFP implodes would be a huge benefit. Instead of $4-5,000 of parts getting ruined, it would only be the $1,000 HPFP and a few filters. I could live with that.

Looking at CP4.1 HPFP pictures, it appears that there is only one high pressure output that goes to the fuel rail and one low pressure output that returns to the tank. So theoretically we would only need 2 filters total to contain HPFP fragments.

I believe a Bronze sintered filter like this:

http://www.grainger.com/Grainger/HASTINGS-FILTERS-Fuel-Filter-2XXY7

Would work fine on the high pressure side. I am not sure the micron rating, but it should catch most of the metal before it heads for the rail and injectors.

For the lower pressure side, I think a simple gas inline fuel filter would be fine to keep metal out of the tank. Would be a fairly simple install too.

I think the biggest issue is figuring a way to put a inline filter on the high pressure side.

 

[Ski in NC]

That is one approach. Probably viable but filter housing would need to be very robust. Also, wear products from the DLC may be very small and some may pass through to injectors. Not too worried about filter deltaP as pump is done by the time filter gets loaded up.

My thinking is in a bit of a different direction: Separate the cam chamber flow and the pumping chamber flow. Presently fuel goes into cam chamber (where there may be wear) and then pumping chamber draws from cam chamber. With some modest plumping changes, the pumping chamber can draw from an ultra-filtered source separate from the cam chamber. Discharge from pump can be filtered, or just dumped back to the tank and let the lower pressure (and lower price) hardware deal with any wear products.

This way if pump grinds itself to bits, injectors, rail and control valves remain pristine. Damage is limited to pump body, cam and followers. Not even whole pump as pumping element and flow control valve should be reusable.

If anyone has a dead pump or two, I will volunteer machine shop time to experiment.

 

[GoFaster]

For the high pressure side, you'll need something like this.

http://www.normanfilters.com/30Khighpressureinlinefilters.html

Inlet and outlet fittings would require some careful thought.

The return line can be any fuel filter.

 

[Waynoooo]

VW are you paying attention? If you do not solve the problem, then we will...and you can by the license from the smart people who built it!

Go boys (and girls) fix it, and then make VW buy a license from you for the design.

 

[pruzink]

Norman filter looks really nice

VW are you paying attention? If you do not solve the problem, then we will...and you can by the license from the smart people who built it!

Go boys (and girls) fix it, and then make VW buy a license from you for the design.

I completely agree that the VW engineers should be COMPLETELY EMBARRASSED that they have allowed this problem to continue for as long as it has. The best that they could come up with was "diesel only" stickers? I had posted a question a while back about putting in filters to contain the shrapnel if the pump failed also. There are people that are installing filters on the return lines, but this doesn't prevent damage to the injectors. The problem with putting a filter on the discharge of the pump is that the pressure is so high. This Norman filter looks really nice and the 30,000 psig rating could definitely handle the pressure. Swagelock makes a compression fitting that is rated for 20,000 psig. With this pressure you wouldn't want to introduce anything that might leak.

 

[c17chief]

To really contain a failure as well as maybe help prevent them to some degree, a filter like the one 2micron offers to protect the return side, one somehow placed between the pump and rail to protect the pressure side, and for my personal comfort, a better lift pump for the tank (something like how the CRD jeep liberties could swap their weak one for one out of a cummins pickup). While not extremely problematic, there is some evidence in some of the stories on here that the lift pump also has its part in the overall fuel system issues scheme of things on these cars.

 

[Celerity]

It's more likely VW's execs, not engineers, who are to blame for this situation...

 

[elitegunslinger]

Sorry seamus,
I certainly will help you out. The return filter is very simple and well worth the effort. You must understand it will not save the pump from failure. It will not save the rail, HP lines or injectors.
It will help contain the damage of a failed pump away from the tank, lift pump, lines and boost pump.
I will get back to your PM, apologies for the last couple of days.Here is a couple of pictures:

All the best,

I have seen a few posts about this but here is something I think will help.

 

[2micron]

Hello everyone, great topic and good discusssions!! Here is some information we discussed a while back about a suitable high pressure filter:


http://forums.tdiclub.com/showthread.php?p=3973834#post3973834


The Norman filter from Gofaster (thanks!) is one of the best, but almost $1000 plus another couple hundred for the element and fittings.
The link above from highpressure.com has information on a suitable filter, much cheaper. Back in April the company quoted around $200 for the filter body and about $100 for the fittings and lines. Very common industry, (water jet cutting and petroleum sour gas drilling) with available fittings and lines.


One of the nice benefits of the cheaper filter is the filter elements are easily replaced and available in different micron ratings.
I'd be happy to experiment with one, just been focused on the CP3 project.


Ski, your idea about adding a filter after the "cam chamber" is brilliant and kudos to you for offering Machine Shop time. I have several sacrificial pumps, but it may be easier to get one from EBay. (shipping cost$$ and border issues from Canada)
There is one on EBay now for $89 or so, from Cali.
Again, great discussion and another worthwhile experiment!!

 

[turbocharged798]

I did some calculations and if you installed a filter like shown above, the only things that would get metal shrapnel is the injectors, rail, and fuel pipes. I see no reason why the hard lines cannot be cleaned. A few blasts of brake cleaner and not much is going to stay inside them.

the fuel rail would probably be a pita to clean and would probably be best to replace that. It runs around $400.

The injectors cost around $1000-1200ish and the HPFP goes for around $1000

Figure around $2600 in parts total. Far cry from $8K. Would be even cheaper if there was a way to have the injectors rebuilt instead of replaced.

One part I do not understand is this: if the hpfp blows and fills the tank with metal, can't you just install a better fuel filter and leave the tank alone? A cat 2 micron fuel filter will filter out all the metal going to the new HPFP.

 

[Central Scrutinizer]

What about machining a custom rail that would include a housing for the inline filter? A custom hard line would likely be needed between HPFP and the new rail, but it seems like the other lines and etc could be reused if the dimensions were maintained. Then a low-pressure filter for the fuel return e.g. elitegunslinger's above.

 

[GoFaster]

You'll need a new hard line for installing any sort of filter on the high-pressure side, anyhow. But making a whole new rail means fabricating a lot more connections. Maybe it's possible make/buy a filter that screws into the outlet of the HPFP and fabricate a new hard line from that to the fuel rail. This way, combined with a return-line filter, any debris would be entirely contained within the HPFP and the filter element itself.

 

[turbocharged798]

You'll need a new hard line for installing any sort of filter on the high-pressure side, anyhow. But making a whole new rail means fabricating a lot more connections. Maybe it's possible make/buy a filter that screws into the outlet of the HPFP and fabricate a new hard line from that to the fuel rail. This way, combined with a return-line filter, any debris would be entirely contained within the HPFP and the filter element itself.

That is heading toward my line of thinking as well. We probably can have a custom hard line with a filter inline made up fairly easily. Best part is retrofitting such a device could be done quickly and easily. You wouldn't even have to remove the HPFP.

My only concern is the filter clogging for whatever reason and causing extreme pressure to build up in the HPFP. Is there a relief valve built into the HPFP at all?

 

[schultp]

I did some calculations and if you installed a filter like shown above, the only things that would get metal shrapnel is the injectors, rail, and fuel pipes. I see no reason why the hard lines cannot be cleaned. A few blasts of brake cleaner and not much is going to stay inside them.

the fuel rail would probably be a pita to clean and would probably be best to replace that. It runs around $400.

The injectors cost around $1000-1200ish and the HPFP goes for around $1000

Figure around $2600 in parts total. Far cry from $8K. Would be even cheaper if there was a way to have the injectors rebuilt instead of replaced.

One part I do not understand is this: if the hpfp blows and fills the tank with metal, can't you just install a better fuel filter and leave the tank alone? A cat 2 micron fuel filter will filter out all the metal going to the new HPFP.

The other consideration beyond the parts cost savings is that with a return fuel line filter saving the tank, lift pump and aux pump the remaining repairs are entirely within access in the engine bay...no dropping the tank and pulling lines from below the vehicle.
Right now, either kerma or boraparts has a complete parts kit for the HPFP replacement including fuel tank for about 4.5K if I recall correctly. So, using a return fuel filter can save about 2K in parts cost along with the DIY labor savings already mentioned.

I'm adding a return fuel filter!

Edit: Here is the link to the boraparts HPFP replacement kit

 

[turbocharged798]

Yeah, adding a return filter is something everybody who owns a CR TDI should do right now. At will at least keep the all the fuel related stuff under the car from contamination.

 

[GoFaster]

My only concern is the filter clogging for whatever reason and causing extreme pressure to build up in the HPFP. Is there a relief valve built into the HPFP at all?

No relief valve at that location. The rail pressure sensor is downstream - in the rail itself, so the ECU won't even know what happened. I strongly suspect that it wouldn't make any difference ... if that filter element clogs to the point of significant back pressure, the pump pressure will probably just blow right through the filter element (breaking it and sending whatever crap has built up until that point, into the rail and injectors).

The upstream filter - the main fuel filter - must filter to a smaller micron rating than the high-pressure filter, so that during normal operation, the high-pressure filter doesn't collect anything at all.

 

[Ski in NC]

Here's my take on fixing options:

1) Holy Grail: Fix the roller/cage/cam interface. Without an internal small OD axle, roller OD rubs on cam and cage on the same diameter. If friction is similar on each interface, roller will skid. Not good.

Fixing that involves building a roller with a small diameter axle, and that may not hold the pumping forces. It might break. Really to do this, need to dig into the whole design.

Look at cam plate rollers on a VE pump. Smaller diameter pins act as axles for the rollers. Big roller OD, small axle OD, same forces, same moments=NO SKID!! Biggee there.

The lack of a rotation lock does not seem to be a big deal, it probably shows up once a failure has already begun.

2) Filter on HP outlet (topic of this thread): Filter must be an extremely small pore size, or DLC (diamond like coating..HARD stuff) particles will go to the injectors, etc. I don't think you will easily configure a filter that has an extremely small pore size and be physically small enough to fit in the small and necessarily robust housing. Clearances on injector moving parts are so small that even sub-micron DLC particles could cause damage. CR injectors stuck open are BAD for engines!!

3) Separate cam chamber and pumping unit flows. I really think this is the way to go if #1 is not fixed. This keeps any debris from cam wear from going to injectors, rail, control valves, etc. The discharge from the cam chamber can be filtered at outlet, or let tank act as a settling volume and the normal filters protect the pumping element. If the sub micron dlc stuff remains a problem, then an ultra tight filter can be put in the inlet to the pumping chamber. That filter can be physically large as pressure there is low.

There is absolutely no reason that the HPFP pumping element has to draw from the cam chamber and suck up that grit!! This is the difference between a $1200 pump replacement and several 1000's to replace the injectors, rail, control valves, etc.

 

[2micron]

Here's my take on fixing options:



3) Separate cam chamber and pumping unit flows. I really think this is the way to go if #1 is not fixed. This keeps any debris from cam wear from going to injectors, rail, control valves, etc. The discharge from the cam chamber can be filtered at outlet, or let tank act as a settling volume and the normal filters protect the pumping element. If the sub micron dlc stuff remains a problem, then an ultra tight filter can be put in the inlet to the pumping chamber. That filter can be physically large as pressure there is low.

There is absolutely no reason that the HPFP pumping element has to draw from the cam chamber and suck up that grit!! This is the difference between a $1200 pump replacement and several 1000's to replace the injectors, rail, control valves, etc.

.
Well said Ski in NC!!!
Hello All!!,
Here is a sneek peak into another fun experiment and yet, more tests.
This adapter isolates the Low pressure Fuel chamber of the Pump from the High pressure chamber of the Pump.
Only fresh, filtered fuel is fed into the Fuel Metering Valve, via a new port, then into the High Pressure Chamber, on its way to the injectors.
This fuel does not come from the Low pressure "pumping chamber" of the pump. Return fuel from the LP chamber is sent back to the tank, through a simple return filter, same as we have seen before.
Very effective way of keeping debris out of the injectors by ensuring only Freshly filtered fuel enters the High Pressure Chamber.
.
In the event of a HPFP failure, the injectors, rail, pressure solenoid and Pressure control solenoid will be saved. The tank, lines, lift pump and Aux (boost) pump will also be saved with the return filter we have seen in previous posts.
.
I will get some better pictures in the daylight. I made it last night, then installed really late last night. Today was a good first test run. My family and I went on a 6 hour round trip to visit our new 2-1/2 month old baby Niece. All went well with the adapter, no issues and more importantly, the little baby Girl is beautiful!!
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All the best!!

 

[bobt2382]

Wow. Ingenious! Let us know when you have these for sale!

 

[red64chevelle]

Here is a sneek peak into another fun experiment and yet, more tests.

I love your science projects. I can't wait for it to go into production, I will be waiting in line for one of those beauties.

 

[Racerman27410]

Loving this work... i think limiting the damage with a setup like this solution is going to make it a little easier for me to own this car once the warranty runs out.

 

[kjclow]

Put me down for two! Always thrilling to see what you guys come up with.

 

[schultp]

2micron does some great work! I just received one of his downstream fuel filter kits and it is high quality and very complete with a great illustrated instruction sheet. I'll be installing it into my JSW tomorrow. I too am very excited about the adapter and await further reports of his field tests.

 

[Ski in NC]

2mic- I think you nailed it. This may be the hpfp fix that saves the cr vw's. No grit to rail and injectors. Cam failure contained. Injectors preserved.

 

[dweisel]

As I've stated before.2micron is the savour for all owners because he has worked so hard to find solutions to ALL of VW's engineering short falls. He has it all covered and will now let CR owners to truely "drive more,worry less.". CONGRATES 2micron!

 

[nicklockard]

.
Well said Ski in NC!!!
Hello All!!,
Here is a sneek peak into another fun experiment and yet, more tests.
This adapter isolates the Low pressure Fuel chamber of the Pump from the High pressure chamber of the Pump.
Only fresh, filtered fuel is fed into the Fuel Metering Valve, via a new port, then into the High Pressure Chamber, on its way to the injectors.
This fuel does not come from the Low pressure "pumping chamber" of the pump. Return fuel from the LP chamber is sent back to the tank, through a simple return filter, same as we have seen before.
Very effective way of keeping debris out of the injectors by ensuring only Freshly filtered fuel enters the High Pressure Chamber.
.
In the event of a HPFP failure, the injectors, rail, pressure solenoid and Pressure control solenoid will be saved. The tank, lines, lift pump and Aux (boost) pump will also be saved with the return filter we have seen in previous posts.
.
I will get some better pictures in the daylight. I made it last night, then installed really late last night. Today was a good first test run. My family and I went on a 6 hour round trip to visit our new 2-1/2 month old baby Niece. All went well with the adapter, no issues and more importantly, the little baby Girl is beautiful!!
.

.
.

.

.

.

.
All the best!!

2micron, Bosch is going to STEAL this design. Just sayin'.

 

[bobt2382]

2micron, Bosch is going to STEAL this design. Just sayin'.

Was thinking the same when I saw this!

 

[Ski in NC]

2mic- call a patent lawyer!! And if all goes well you owe me a case of beer!!

 

[dweisel]

2mic- call a patent lawyer!! And if all goes well you owe me a case of beer!!

That was the exact advice I gave 2micron when he pm'ed the other day and he doesn't even owe me one beer. LOL

Huge props to 2micron because this breakthrough is truely HUGE!

Andrew, once you get production started. Your adapter needs a special place on this forum to promote it. It truely is and will be a tremedous acheivement towards making the CR fuel system somewhat less worry free by mitigating damage to the entire fuel system. It will mean no more entire fuel systems replacements. Huge dollar savigns to owners with failures.

All CR owner's need to give you a hug and a salute for solving a problem that has the potential to totally ruin the service life of the CR VW.

Greatest respects for your hard work and perseverance.
dweisel
__________________

 

[GoFaster]

Wow ... Mad props! Looks like an OEM installation ... the way the OEM installation SHOULD have been!