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Getting an electronic fuel injector to only open partially
ELS122:
How do I make a gasoline fuel injector open partially? I tried just undervolting one but no matter what I tried it would just be either fully open or fully closed.
Maybe using high frequency AC with a DC offset? Maybe there's a specific type of injector that allows this?
The reason I want this is to be able to adjust the fuel particle size on-the-go. To maximize engine efficiency over the entire rpm range.
I'm not very concerned about the impact of fuel flow when the injector is partially open, since I can compensate for that later and I just want something that gives me an adjustable particle size first.
bdunham7:
--- Quote from: ELS122 on June 04, 2023, 04:16:06 am ---The reason I want this is to be able to adjust the fuel particle size on-the-go. To maximize engine efficiency over the entire rpm range.
I'm not very concerned about the impact of fuel flow when the injector is partially open, since I can compensate for that later and I just want something that gives me an adjustable particle size first.
--- End quote ---
What effect on fuel droplet size do you anticipate from various pintle positions? I'm just curious...
As for hanging a solenoid valve in an intermediate position, I think it would be pretty tricky. You would have to do something like using a PWM signal and then somehow measuring the pintle position (via a change in inductance) in between the pulses using some sort of test signal. Or something like that. I don't think typical port injector changes inductance much during the intermediate phase that you are looking to stabilize, so...
ELS122:
--- Quote from: bdunham7 on June 04, 2023, 04:39:01 am ---
--- Quote from: ELS122 on June 04, 2023, 04:16:06 am ---The reason I want this is to be able to adjust the fuel particle size on-the-go. To maximize engine efficiency over the entire rpm range.
I'm not very concerned about the impact of fuel flow when the injector is partially open, since I can compensate for that later and I just want something that gives me an adjustable particle size first.
--- End quote ---
What effect on fuel droplet size do you anticipate from various pintle positions? I'm just curious...
As for hanging a solenoid valve in an intermediate position, I think it would be pretty tricky. You would have to do something like using a PWM signal and then somehow measuring the pintle position (via a change in inductance) in between the pulses using some sort of test signal. Or something like that. I don't think typical port injector changes inductance much during the intermediate phase that you are looking to stabilize, so...
--- End quote ---
Well a big difference, smaller outlet orifice = higher velocity = more breakup, atomization.
The problem is that fuel injectors are already meant for PWM, they are PWM driven to control the fuel flow by changing the duty cycle, and at 8000rpm, the whole intake cycle happens in around 2 miliseconds, and in that time span they're PWM controlled... who knows how extremely fast you'd have to drive them to control the position... 10khz? 100khz?
Oh and btw they are normally triggered at a much higher current, triggered around 11 amps then held with 500mA. presumably to make them open faster, and when they're open lower the current so they dont melt
AndyBeez:
What kind of fuel injection are you trying to modify - direct cylinder or manifold are common 'modes' of injection.
https://en.m.wikipedia.org/wiki/Manifold_injection
https://en.m.wikipedia.org/wiki/Petrol_direct_injection
https://en.m.wikipedia.org/wiki/Common_rail
Lots of options. EFIs are often optimised to the mechanics, at great expense to the engine manufacturers.
ELS122:
--- Quote from: AndyBeez on June 04, 2023, 08:43:34 am ---What kind of fuel injection are you trying to modify - direct cylinder or manifold are common 'modes' of injection.
https://en.m.wikipedia.org/wiki/Manifold_injection
https://en.m.wikipedia.org/wiki/Petrol_direct_injection
https://en.m.wikipedia.org/wiki/Common_rail
Lots of options. EFIs are often optimised to the mechanics, at great expense to the engine manufacturers.
--- End quote ---
Port injection, Direct injection wouldnt benefit from this.
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