Author Topic: Fuel injection systems  (Read 43709 times)

Offline Kim

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Re: Fuel injection systems
« Reply #75 on: January 31, 2016, 04:13:33 PM »
That's great Roger!  You're getting there!  :ThumbsUp:
Quite the fiddly little gizmo isn't it?
Kim

Online Roger B

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Re: Fuel injection systems
« Reply #76 on: May 20, 2016, 06:54:22 PM »
The next step is to make an excentric so I can drive the pump. The excentric rod is a piece of 2mm brass. I could have had lots of fun with the RT but decided in this case a hacksaw and file would be quicker.
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #77 on: May 26, 2016, 07:10:30 PM »
The excentric was turned from free cutting mild steel to 16mm and then offset 1.5mm in the four jaw chuck and turned down to 12mm.

I then needed to put a slot in the end of the stroke adjusting wedge. This is made from 4mm square key steel and the deflection was too much using a 2mm end mill. I couldn't hold it sensibly to use a slitting saw or slot cutter so finally hacksawed and filed the slot. Next time I will cut the slot before cutting the wedge face.
Best regards

Roger

Online Jo

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Re: Fuel injection systems
« Reply #78 on: May 26, 2016, 07:38:59 PM »
Next time I will cut the slot before cutting the wedge face.

 ;)

Jo
Usus est optimum magister

Offline fumopuc

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Re: Fuel injection systems
« Reply #79 on: May 26, 2016, 07:45:05 PM »
The next step is to make an excentric so I can drive the pump. The excentric rod is a piece of 2mm brass. I could have had lots of fun with the RT but decided in this case a hacksaw and file would be quicker.
Hi Roger, sometimes this old fashioned way is the best and easiest way to go.
« Last Edit: May 29, 2016, 06:13:30 PM by fumopuc »
Kind Regards
Achim

Online Roger B

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Re: Fuel injection systems
« Reply #80 on: May 28, 2016, 06:36:00 PM »
Thank you for your interest and support  :ThumbsUp:  :ThumbsUp:

I finished off the excentric and then made a mounting plate to fit the pump and stroke adjuster onto the side of my horizontal engine. For the trial video I removed the spark plug and motored the generator with a 6V battery.

<a href="http://www.youtube.com/watch?v=Gh_DrUwlSgI" target="_blank">http://www.youtube.com/watch?v=Gh_DrUwlSgI</a>
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #81 on: May 29, 2016, 06:10:35 PM »
I then set the pump in place, using a 1mm drill in the inlet port to ensure it was fully open. The next pieces were a link to connect the wedge to the adjustment block and the adjustment block. As the adjustment block was brass rather than key steel I could cut the 2mm slot without problems using a 2mm end mill.
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #82 on: May 29, 2016, 06:16:15 PM »
I had a commercial (RC Machines?)M2 bolt that was suitable for the top pivot pin of the link. I still need to make a couple of proper 2mm pivot pins as well as the adjusting screw and top bearing but enough bits moved to make another video clip (apologies for the quality, poor light and hand held).

<a href="http://www.youtube.com/watch?v=W5TFGkM3ujo" target="_blank">http://www.youtube.com/watch?v=W5TFGkM3ujo</a>
Best regards

Roger

Offline fumopuc

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Re: Fuel injection systems
« Reply #83 on: May 30, 2016, 02:20:09 PM »
Hi Roger, interesting mock up. Waiting for the next experiments.
Kind Regards
Achim

Online Roger B

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Re: Fuel injection systems
« Reply #84 on: May 31, 2016, 06:03:19 PM »
Thanks Achim  :ThumbsUp: With luck I will be trying petrol injection in a couple of weeks  ::)

Before I went back to lathe mode for the pivot pins and adjusting screw I decided to make the inlet manifold/adaptor for the injector. I milled an 8mm diameter recess at 30 in some 6mm dia. brass tube and silver soldered it onto the side of some 8mm dia. brass tube. The passage was then opened out with a centre drill followed by a 5mm drill. I will reuse the flanges from an existing carb adaptor so I can use a carb simply as a throttle.
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #85 on: June 04, 2016, 07:58:52 PM »
I fitted the flanges to the manifold. Unfortunately the engine end flange cracked when I removed it from the original pipe but I was able to soft solder it back together.
I finished off the pivot pins and adjusting screw and put it all together. As expected the pump had problems reaching a suitable pressure with cooking alcohol so I will need to make a new pump body and possibly a new plunger.
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #86 on: June 18, 2016, 06:36:29 PM »
I took a video clip of the adjuster in operation but the aspect ratio seems to be confused  :headscratch: The engine was being driven with a 6V battery via the generator. I have started on a new pump body and plunger, I'm following the same way as before but hopefully without mistakes  ::)

<a href="http://www.youtube.com/watch?v=4kLwTbrFDtA" target="_blank">http://www.youtube.com/watch?v=4kLwTbrFDtA</a>
« Last Edit: June 18, 2016, 07:04:15 PM by Roger B »
Best regards

Roger

Online Roger B

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Re: Fuel injection systems
« Reply #87 on: October 02, 2016, 04:24:27 PM »
I started making a new body but was still puzzled as to why I got the pump to work by hand for the first test. Careful measurement showed that the last 2mm of the plunger tapered by around 5 microns, this being the section used when being driven by the engine. When I did the hand trials I was using more of the plunger length.

I decided to try and cut the tapered 2 mm off the plunger using a cutting disc in the Proxxon as the plunger was otherwise a 'trial piece'. The mounting screw holes were then slotted to compensate.

This actually produced a sort of spray that could be adjusted and seemed to have a range of 100-150mm  :)  :)  :)

<a href="http://www.youtube.com/watch?v=1LbJLUJa0-k" target="_blank">http://www.youtube.com/watch?v=1LbJLUJa0-k</a>
Best regards

Roger

Offline Brendon M

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Re: Fuel injection systems
« Reply #88 on: October 09, 2016, 02:30:22 AM »
5 microns is not much! If I understood your posts correctly, this was enough to prevent sufficient pumping?
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Online Roger B

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Re: Fuel injection systems
« Reply #89 on: October 09, 2016, 07:18:51 AM »
5 microns clearance is definitely too much. With careful lapping I am trying to get to 1 micron or less clearance.
Best regards

Roger