evinrude ETEC injector

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evinrude ETEC injector

Postby MS2tester » Mon Feb 23, 2015 8:14 am

this is an idea i am playing with
since looking at the schematic the injector driver seems to be isolated from the rest of the electrical system

the ETEC injector is a 2 to 3 ohm injector which operates at 55 volt
the 33 volt zener? new value? = will probably have to be substituted but other than that
could this work ?
Attachments
etec_stator_output.jpg
etec_stator_output.jpg (254.93 KiB) Viewed 3717 times
etech-fuel-injector.jpg
etech-fuel-injector.jpg (53.55 KiB) Viewed 3719 times
www.ti.com_lit_ds_symlink_lm1949.pdf
(69.12 KiB) Downloaded 115 times
Last edited by MS2tester on Mon Feb 23, 2015 11:33 am, edited 1 time in total.
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Re: evinrude ETEC injector

Postby jbelanger » Mon Feb 23, 2015 11:30 am

First you'd need to know what the peak and hold values are. The LM1949 is limited to a 4:1 ratio so if that doesn't fit the injector, there's nothing that can be done to adjust it. Also, 55V will mean a lot of heat dissipated in the transistor if the current has to be held at a relatively low value.

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Re: evinrude ETEC injector

Postby MS2tester » Mon Feb 23, 2015 12:01 pm

the original ecu is water cooled
i just thought of the fuel running through the injector
it could be designed this way to cool the injector coil
so i guess the driver could be a heavy duty mosfet against a water cooled body?
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etec_ecu.jpg
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Re: evinrude ETEC injector

Postby jbelanger » Mon Feb 23, 2015 12:18 pm

The LM1949 is not designed to work with a mosfet, it uses a Darlington like the TIP122. But you still need to get the peak&hold specs for the injector. I don't see anything in what you posted to indicate that the injector needs a peak&hold or what current it should use.

As for water cooling, that could be a way to go. If the hold current is 1A as for regular p&h injectors, you would have to get rid of around 50-55 Watts of heat per driver which is huge.

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Re: evinrude ETEC injector

Postby MS2tester » Mon Feb 23, 2015 2:27 pm

the original ecu seems to be very advanced
being able to send reverse pulses :roll:

i did manage to find something in a thesis paper
https://drive.google.com/file/d/0B2M1nE ... sp=sharing
Attachments
etec_injector_current.pdf
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etec_injector_explained.pdf
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Re: evinrude ETEC injector

Postby jbelanger » Mon Feb 23, 2015 2:33 pm

So that's not a peak&hold injector. Full voltage is applied with the corresponding high current for the duration of the pulse. What you need is a FET big enough to handle the current and the flyback and the ECU to do the needed injection strategy.

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Re: evinrude ETEC injector

Postby MS2tester » Mon Feb 23, 2015 3:32 pm

i think i will focus on the mercury optimax engine for now :geek:
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Re: evinrude ETEC injector

Postby dontz125 » Mon Feb 23, 2015 4:21 pm

jbelanger wrote:What you need is a FET big enough to handle the current and the flyback and the ECU to do the needed injection strategy.

BUK9Y12-100E,115 - Logic-level N-MosFet, 100v, 85A, Rds(on) of 9.5mOhm. Barely even get warm ...

I read the notes on the fancy 'braking' pulses, one as it comes to full-open, the other coming to full-closed. It would be interesting to set one of these things up on a test bench and run it at the max frequency your installation will see, just to see how long it takes to shake apart without the braking pulses. If you can run it at (effectively) WFO for some ridiculous duration, then it really isn't necessary ...
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Re: evinrude ETEC injector

Postby MS2tester » Tue Feb 24, 2015 7:07 am

maybe it,s a little less complicated as originally thought
but still quite a component build :roll:

i,m not an electronics expert
but the ecm seems to control switch 318 for the reverse signal pulse
the injector runs on the 55 volt
if instead of having switch 318 controlled by the ecu connect a zener diode between the switch and the negative side of the injector
with say a value of 75 volt
when the injector is turned off this value is crossed because of the flyback and starts conducting
thus turning on the switch ( thyristor ) and release the capacitor?
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US7287966.pdf
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