Fuel injector test unit with weird circuitry
Added 2023-03-22 00:35:21 +0000 UTCI'm not sure if there are multiple variants of this unit or if it's just another stolen design with legacy circuitry and software.
The software is terrible. Really basic, and the only way to change mode is to force a processor reset and start from the beginning.
The dual voltage functionality has me perplexed. The only thing I can think of is that it may be designed to initially power the injector at 12V then step down to a lower voltage once the solenoid has pulled in, to reduce dissipation.
https://www.youtube.com/watch?v=IyTHihEJX_M
Comments
Darn! I wish I'd read this just before recording the new version of this video with a scoped waveform showing the voltage switching. I'll add that to the description of the new video.
Big Clive
2023-03-23 00:08:01 +0000 UTCThe 2 voltages is "Peak and hold" - A higher current pulse opens the valve, a lower current holds it open and allows the magnetic field to partially reduce, so there's a lower residual magnetism when the valve needs to close quickly. It's for magnetic reasons.
Andy Brown
2023-03-22 22:29:24 +0000 UTC13.8V tends to be a good threshold for determining whether an engine with 12V ignition is on or not (the voltage when running will be 14Vish) as it allows for both strong batteries that will hover over 12V for a while after switch off and weak alternators. That being said, to me it doesn't seem like a good idea to test injectors in place while the fuel pump is running - and would not cater for smarter alternators that drop off once the battery is charged - but perhaps "because China" comes into play.
Paul Menghorne
2023-03-22 12:35:25 +0000 UTC
