[help needed] Low impedance injector driver

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AndreyB
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Low impedance injector driver

Post by AndreyB »

https://svn.code.sf.net/p/rusefi/code/trunk/hardware/Low-Z_LM1949/


This is not exactly a pressing issue, but since I was just given a great link - http://www.robietherobot.com/storm/fuelinjectorguide.htm - which made me go through my drawer and I find turbo ford low impedance E5ZE-A3B injectors...

So, is there maybe some chip which does the job?

Jared, PM me if you want me to mail you one or two for tests.
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abecedarian
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Re: Low impedance injector driver

Post by abecedarian »

That site states: "•500cc per minute is approximately equal to 49lbs per hour which is equal to approximately 100hp. "
I can say with authority that 330 cc/min can generate nearly 100hp as the fuel injectors used in the CX650T are 330 cc/min and that engine produces just a tad short of 100 hp. So, 370 cc/min injectors can absolutely reach 100hp without issue. The trick is realizing that you can bump the fuel pressure and increase the total flow without needing to increase injector duty cycle. That is with two cylinders and a turbo, so maybe that's the point? One injector can provide fuel for XX hp?

If you keep the fuel pressure down near 38-43 PSI, then you might need injectors that large to achieve that much HP... if you don't have enough cylinders.
... and my '91 Toyota pickup 22re goes over 100hp with whopping ~280 cc/min injectors.

Visit http://rceng.com/technical.aspx to help you figure it out... and even Robby points you there too. So what's Robby smoking? Robby doesn't even mention brake specific fuel consumption.
:roll:

RC tells me that 330 cc/min injectors (x2) should get me just above 100hp at the rear wheel, on my motorcycle, that goes from 28 PSI fuel to 65 PSI fuel pressure under boost.
Your mileage may vary. ;)


Anyhow, http://www.jbperf.com/p&h_board/index.html uses LM1949 and other components.

I haven't found a 'stand alone' driver, yet.
You can lead the horticulture but you can't make them think.

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abecedarian
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Re: Low impedance injector driver

Post by abecedarian »

I love playing the devil's illiterate advocate, sometimes. ;)
You can lead the horticulture but you can't make them think.

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kb1gtt
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Re: Low impedance injector driver

Post by kb1gtt »

some time ago I helped Marcos with puma, which uses a low z see schematic and kicad source found here

http://puma.freeems.org/docs/Puma_spin1_schematic.pdf
https://github.com/nitrousnrg/puma

That fellow noted that as a general ball park rule you can correlate flow rate to HP there are many ways it can vary. Say sequential vs non sequential, ect.
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hasse.69
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Re: Low impedance injector driver

Post by hasse.69 »

Yes 1 (one) 500cc injector will give you roughly 100hp
Yes 2 (two) 330cc injectors will give you 100+hp (330cc x 2 = 660cc)
Yes 4 (four) 280cc injectors will give you 100+hp (280cc x 4 = 1120cc)

Not to be smarty pants but if you´ve got 1 ,2 or 4 injectors actually make a difference. :)
So is pressure.
Jbperf also have a standalone or complete driver for four low-Z injectors
http://www.jbperf.com/p&h_board/v2_0_1.html
95$ plus 20-25$ shipping. :|
Or maybe this one is going to work to:
http://www.jbperf.com/p&h_board/index.html#V1.1A
For 18-58$ plus 4-6$ shipping
Best regards , Hasse
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AndreyB
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Re: Low impedance injector driver

Post by AndreyB »

Can we please make a little board for the LM1949 chip since these are still widely available? https://octopart.com/search?q=LM1949

Yet another person is asking for one at http://rusefi.com/forum/viewtopic.php?f=10&t=1178
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Rhinoman
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Re: Low impedance injector driver

Post by Rhinoman »

russian wrote: So, is there maybe some chip which does the job?
This is something that I need to look at, the injector driver on my ECU is a hybrid circuit that uses some comparators and a few discrete devices. The downside is that a drives an NPN/PNP Darlington pair and there are limited options available for those these days. I was considering a small micro with a built in comparator. The LM1949 is a very old chip and uses a timer for the peak detect so its not much better than a PWM circuit.

Edit: I just re-read the datasheet, the timer is a failsafe, I think that the issue I had previously was that the peak is 4x the hold and I had a requirement for 3x the hold. Its still requires a Darlington though, surprisingly the application note shows a low-side drive only.

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V8Volvo245
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Low impedance injectors

Post by V8Volvo245 »

I've just discovered that my engine has low impedance, side feed 350cc injectors. I've also noticed that the Wiki states that RusEFi cannot handle them. Is this information still correct, is there a workaround or am I stuck with spending a fortune on a new set of injectors if I want to use this ecu? :(

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V8Volvo245
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Re: Low impedance injector driver

Post by V8Volvo245 »

Actually, scratch that-14ohms. Seems like I was given duff information. Don't believe everything you read on the Internet, kids! :lol:
IMG_20180402_185130_652.jpg
IMG_20180402_185130_652.jpg (120.94 KiB) Viewed 3162 times

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kb1gtt
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Re: Low impedance injector driver

Post by kb1gtt »

V8Volvo245 wrote:
Mon Apr 02, 2018 5:54 pm
Don't believe everything you read on the Internet, kids!
I don't which means I'm not going to believe you are all set with the high impeafance injectors.

Good to hear your all set. Keep up the good progress.
Welcome to the friendlier side of internet crazy :)

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AndreyB
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Re: Low impedance injector driver

Post by AndreyB »

This schematics was never tried so moved to https://github.com/rusefi/hw_legacy/tree/master/Low-Z_LM1949 for now
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