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Post by Johansson on Nov 9, 2019 10:35:42 GMT -5
Hi! I dont remember what size nozzles we talked about using, but the idea is to size them so they give the idle fuel flow at pretty high fuel pressure for good misting and less risk of flameout at sudden throttle releases.
We will have a separate pump for them with a mechanical regulator to adjust the fuel pressure.
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Sweetenough
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Post by Sweetenough on Nov 11, 2019 2:26:23 GMT -5
Thanks Anders, My initial idea was to start the engine to idle on propane and then shift over to diesel. Made some attempts during the first starts but failed (Most likely due to operator error, never tried it further) Like the idea a lot but I think a stick to propane for now if I can get it to work with the modifications I made. If I rembemer correctly you had some design like this on the latest one engine kick? And used some kind of oil burner nozzle? Will follow your progress closely as usual :-)
Kind regards Thomas
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Post by Johansson on Nov 11, 2019 16:11:54 GMT -5
Yup, and I used it on my jet pocket bike back in 2007 which was the first time I saw it on a DIY engine.
A simple Danfoss hollow cone nozzle is all you need, just keep it flowing fuel all the time since it will melt otherwise.
Puss & kram /Anders
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Sweetenough
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Post by Sweetenough on Nov 12, 2019 1:11:08 GMT -5
Thanks Anders, Will buy a few nozzles and do some testing. Puss Å kram tebax
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Post by Johansson on Nov 13, 2019 14:48:36 GMT -5
Just do it! Kero preheat is the best, propane is gay.
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Sweetenough
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Post by Sweetenough on Nov 15, 2019 3:02:33 GMT -5
Hi Anders, Do not have room for another fuel pump right now Tried to figure out what nozzle size I should order for a test. Calculated that the engine consumes around 0,45 liters/minute at idle 40krpm But when I try Danfoss size guide all nozzles seems to small, biggest nozzle gives around half that amount? Any ideas? My flow calculation could also be wrong.... Did you use a 044 pump or something else? Just finished the pilot propane installation yesterday. So there might be some testing noice this weekend Just need to finish the new AB fuel pump installation Kind Regards Thomas
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Sweetenough
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Post by Sweetenough on Feb 5, 2020 9:05:42 GMT -5
Hi Guys, Have finished the new propane preheating system, works really well. Ignites every time with the pre-set needle valves. So that is a big improvment from the old solution that was a difficult to ignite and then it melted the sparkplugs every run New AB pump is installed and tested, I now definitely start to hear some audible screech so should begin to approach the maximum fuel limit. However the new pump and enlarged fuel nozzles stil does not produce enough AB fuel. Perhaps I will use the fuel auxilary unit to really test the stability limit And I finally tried AB ignition with spark plug, worked really well! Why have I not tried this before? youtu.be/Yk0tvyFnDSANew AB pump Fuel auxilary unit for future testing So everything is more or less ready for speedweekend on ice in the end of february, but.... we are lacking ice more or less. Hoping for really cold weather for the rest of the month but for the moment it is way to warm Kind Regards Thomas
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Sweetenough
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Post by Sweetenough on Feb 25, 2020 2:50:21 GMT -5
Hi Guys, Speedweekend canceled due to lack of ice, so no real test of the improments this year However the development is continuing, my brand new solution with an oil thermostat will be rebuilt The drawback of having the themostat on the feed line to the engine is that the tank temperature is more or less what is, stabilizes at around 100°C. And at that temperature the oil pump is starting to have problems to give the desired oil pressure. So what to to? Make it more complicated? Oh yes!!! Will remove the oil thermostat and install a small circulation pump that will circulate the oil from the tank through the cooler and back to tank. Aiming to PWM control both pump and cooler fan based on tank temperature. It will be an Arduino project to create a free standing control module for the lube oil since I am out of I/O channels on my main ABB control system. Have very limited previous experience in Arduino so maybe this project will open the door to the Ardunio world Hopefully the result will be that I can keep the oil temperature low enough so that the pump can deliver 5 bar. Have also got help to implement a nice feature in the datalogger, modified a crane scale and connected the load cell directly to a HX711 board and then to the Raspberry logger. Had to buy another scale and build a small test rig to do a calibration. Worked really well and will be great for future testing to have thrust in the same logger as the engine data Kind Regards Thomas
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Post by racket on Feb 25, 2020 3:16:05 GMT -5
Hi Thomas
Its a really good idea to get accurate thrust measurements from our engines, those readings can then be used to verify other engine data , the calculations can be worked back and forth between the various components .
With my TV84 engine testing I had the entire engine/bike suspended in mid air and the thrust measuring spring balancers mounted each side of the jetpipe to minimise any "couple" forces exagerating the thrust level.
Yep , tank oil temps need to be ~50-75C so that the addition of heat within the turbo doesn't "cook" the lube at the hot turb end where temps will rise significantly , the average turb outlet temp can be 30C degrees hotter than the inlet temp .
Cheers John
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Sweetenough
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Post by Sweetenough on Feb 26, 2020 5:03:32 GMT -5
Hi John, Thanks for your comments, have a little bit of a friction issue with the complete vehicle. Quite heavy and standing on skates, best solution so far is to put bits of 40mm pipe under the skates but I think (hope) there still is some friction losses. For a while I was considering making big blocks of ice to have under the skates Suspending it mid air would be a quite challenging task in my workshop but I like the idea. I am still amazed of the amount of heat transfered to the oil. In my first design I expected the oil tank in aluminium to be enough to cool the oil.... I think a lot of the oil pressure problems that seems very common in DIY jet buissness is related to insuffient oil cooling. Hope that the new system design takes me one step closer to high and steady oil pressure. Kind Regards Thomas
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Post by racket on Feb 26, 2020 16:01:00 GMT -5
Hi Thomas
The problem with relying on the oil tank surface for heat transfer is that the oil in contact with the cool surface has its viscosity increased and it tends to "stick" in place and then acts as a "blanket" preventing fresh hot oil from contacting the surface , we end up with a temperature gradient across the wall and layer of lube attached to it, with the bulk of the hot oil simply not coming in contact with a cool surface .
With your thrust measuring , try tilting the machine so that its wanting to move , the thrust measuring device will have a reading registering the load being applied in the opposite direction to prevent movement , simply remove that amount from your final thrust measurement to get your engine "force"
Cheers John
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Sweetenough
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Post by Sweetenough on Apr 20, 2020 9:42:40 GMT -5
Hi Guys, Have made some progress, removed the newly installed oil thermostat and installed a separete oil cooler circulation pump. Was quite a thight fit to get connections needed into the oil tank. Got hold of some really nice banjo AN fittings. Remains to build the control unit for the pumps and fan. Then I can make some noise again :-) Kind Regards Thomas
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Sweetenough
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Post by Sweetenough on May 5, 2020 5:59:50 GMT -5
Hi Guys, Learned the hard way that there are 2 different pumps with the same apperance, one for diesel/water and an another type for oil. Of coarse I had the diesel/water version that became very hot almost immediately when running it. Got the correct (low speed version) of the same pump and now the motor temp is ok. Then finally I managed to get some result with the arduino programing and after countless tries I now have control over the LCD display Will make a wood board test setup to check the functions while programming (uphill battle... ) Hope to achive PWM pressure and temperature control with an arduino nano Kind Regards Thomas
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slittlewing
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Post by slittlewing on May 5, 2020 16:31:19 GMT -5
Great stuff Thomas! If you need I can provide you with my high side driver circuit details, which you can use to do positive switching on the pumps from the low level arduino 5v outputs coverted to PWM with 70A at 12v (twin mosfet for oil pump) or 35a for fuel pump.
Cheers
Scott
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Post by turboron on May 6, 2020 7:32:43 GMT -5
Scott, I would like the information on your high side driver circuits details as posted in your comment to Thomas. This is the set up I plan to use for my Arduino control.
Thanks, Ron
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