Author Topic: Fuel Injection Systems Part 2  (Read 7703 times)

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #15 on: March 12, 2022, 08:51:56 AM »
Hi Per, I did look at that design, it does solve a number of problems but the killer is how to get the air out of an inverted plunger  ::) The optimum seems to be a horizontal pump with vertical valves as was used on many of the hot bulb/semi diesel tractors. The example from Lanz uses a spring loaded cone valve and a gravity ball valve in tandem, no idea why  :headscratch:
Best regards

Roger

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #16 on: March 20, 2022, 07:43:26 PM »
I looked at the horizontal petrol engine whilst it was running and the was no obvious leakage from the plunger. This engine has the first injection pump I made and quite a few running hours so I decided to dismantle and check the pump I made for the vertical engine, not good  ::)
The plunger measured at around 1.965 so about 5 microns undersize. A 1.98 mm pin gauge would enter the barrel for 5 - 6 mm. With the 1.98 mm pin gauge in the barrel there was no detectable leakage and the fuel feed pump held pressure for 10s of seconds. A 1.99 mm pin gauge would enter the barrel for 1 - 2 mm.
I evidently got something wrong during the making of the plunger and barrel and will probably have to remake both  :( maybe I can save the pump element but the 1.965 plunger is not useable.

The leaking fuel washing the lubricant away fron the excentric and plunger caused significant wear in less than 5 mins running. I haven't measured it but I think a new excentric strap will be required  :toilet_claw:

https://youtube.com/shorts/wEaZnRayJUs?feature=share
« Last Edit: December 04, 2022, 05:12:59 PM by Roger B »
Best regards

Roger

Offline Mike R

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Re: Fuel Injection Systems Part 2
« Reply #17 on: March 20, 2022, 10:00:10 PM »
Hi Roger,
I glanced back in this and the previous thread but didn't see a drawing of the general arrangement of the pump, or injector.  Do you have one you can point me to?  I'm not familiar with this type of pump but would like to know more.

Regards
Mike

Online Kim

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Re: Fuel Injection Systems Part 2
« Reply #18 on: March 20, 2022, 10:53:35 PM »
Hi Roger,
Sorry for the problems :(  But isn't that always the way it goes?  :-\
But that's why we love the hobby, right?

Your video doesn't seem to work for me. Is it public?

Thanks,
Kim

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #19 on: March 21, 2022, 08:05:53 PM »
Thank you both  :)

YouTube seems to have uploaded this as a video short (????) and I can't see it on MEM. I have tried to upload it again:

<a href="https://www.youtube.com/watch?v=qhWlly2ebUA" target="_blank">http://www.youtube.com/watch?v=qhWlly2ebUA</a>

<a href="https://www.youtube.com/watch?v=qhWlly2ebUA" target="_blank">http://www.youtube.com/watch?v=qhWlly2ebUA</a>

Mike, This is a bit made up as I go along, my drawings are electronic back of an envelope sketches. Here are a couple of exploded views, I will try to do a couple of decent layouts. The pump is based on a full sized jerk pump with helix metering. The injector is based on a GM pintle design.
« Last Edit: December 04, 2022, 05:14:23 PM by Roger B »
Best regards

Roger

Online Kim

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Re: Fuel Injection Systems Part 2
« Reply #20 on: March 21, 2022, 10:07:47 PM »
Yup, I can see the video in your latest post!
Thanks Roger,
Kim

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #21 on: March 22, 2022, 01:55:51 PM »
 :ThumbsUp:

Here are layouts of the pump and injector. Hopefully they will make sense together with the exploded parts.
Best regards

Roger

Offline Mike R

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Re: Fuel Injection Systems Part 2
« Reply #22 on: March 23, 2022, 12:57:42 AM »
Thanks Roger,

That was enough information to enable me to give myself a youtube education in jerk pump with helix metering.  Looking forward to your progress with these miniature examples.

Mike

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #23 on: April 02, 2022, 03:29:53 PM »
I lapped the element out to 1.98 mm and ground two new helixes in a 1.98 mm pin gauge. These were then cut to length and the non helix end was annealed then threaded M2. This was all much as before except I used an ER11 chuck rather than an ER25 to get better access.

The pump was rebuilt, fitted to the engine, primed and tried.

<a href="https://www.youtube.com/watch?v=I96e8rIJkbs" target="_blank">http://www.youtube.com/watch?v=I96e8rIJkbs</a>

It ran quite well with no obvious leakage from the pump, but a seep from the injector that looks to be due to a crack in the soldered joint at the union.

Now the lubricant is not washed away from the rack mechanism it tends to move on it's own and has to be held. Progress in one way but I only have two hands so cannot measure RPM etc.

Next up is to repair or replace the injection pipe. I have always hard soldered the unions on the diesel versions. Then I need to sort out a control mechanism for the rack.
Best regards

Roger

Offline RReid

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Re: Fuel Injection Systems Part 2
« Reply #24 on: April 02, 2022, 05:07:54 PM »
Good job getting that tough nut to crack, Roger!  :cartwheel: :wine1:
Regards,
Ron

Offline Roger B

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Re: Fuel Injection Systems Part 2
« Reply #25 on: April 02, 2022, 08:19:49 PM »
Thank you Ron  :)

This fuel injection thread is a bit of a lonely path  ::) I know some people have got it to work but there are no real details available. If I can even list what doesn't work and why I will hopefully add to the knowledge base. The goal is to give a way to build your own injection system  :)
Best regards

Roger

Offline steamer

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Re: Fuel Injection Systems Part 2
« Reply #26 on: April 02, 2022, 11:23:44 PM »
It's' a runnah Roger!!!  That is a definite success!!    I've seen others runninn, but none of them were running at that speed!!!

Good job Man!!!!!! :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp: :jumpingsmileys:

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline MJM460

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Re: Fuel Injection Systems Part 2
« Reply #27 on: April 03, 2022, 12:22:58 PM »
Hi Roger, It might seem like a lonely path, but I am sure that I am not the only one that looks forward to and reads every post.  I like your detailed record of the process with the descriptively titled pictures.

I am in awe of the accuracy your are achieving, and your patient approach to developing solutions to the problems one by one.

Great to see the current stage running so well in that video.

MJM460

The more I learn, the more I find that I still have to learn!

Offline propforward

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Re: Fuel Injection Systems Part 2
« Reply #28 on: April 03, 2022, 02:21:08 PM »
I really appreciate your detailed explanations - that is a heck of a good result. Superb running engine!
Stuart

Forging ahead regardless.

Offline Minh Thanh

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Re: Fuel Injection Systems Part 2
« Reply #29 on: April 03, 2022, 04:16:02 PM »
Engine runs great , You have succeeded  :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:.
Congratulations !
Thanks for sharing  !!!

 

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