Technical > Fuel Injection
Moving from batch fire to fully sequential
[email protected]:
--- Quote from: Arthur on August 27, 2009, 03:50:21 am ---
When the cyl 1 is ignighting, cyl 4 is traveling down to and in inlet so the inlet valve is open. ??? ???
--- End quote ---
You know - you're quite right.
Lets see...
InductionCompressionIgnitionExhaustion1342213442133421
In the first case 4 is igniting, so you want to inject on 3 or 2
Arthur:
Oké.
I just read in in a way that made me think you ment different. :-[
Just for the complete picture. Not injecting on open inlet is only applicable under low load and rpm. Isn't it?
On high 7500 rpm, 1.2 boost, 70% duty cycle and 285 deg cam you will always inject to fuel in a same way as emtying a bucket of fuel in the header.
[email protected]:
--- Quote from: Arthur on August 27, 2009, 08:18:38 pm ---I just read in in a way that made me think you ment different. :-[
[/qoute]
Well what it comes down to is when the injection event occurs, and that is on the trigger tooth - which is 100 to 60 deg BTDC.
So 1 will be compressing, and 4 will be exhausting.
--- Quote from: Arthur on August 27, 2009, 08:18:38 pm ---Just for the complete picture. Not injecting on open inlet is only applicable under low load and rpm. Isn't it?
On high 7500 rpm, 1.2 boost, 70% duty cycle and 285 deg cam you will always inject to fuel in a same way as emtying a bucket of fuel in the header.
--- End quote ---
Exactly right, although reports vary on the effects of timed/phased injection at higher RPM regarding improved power and lower emissions, but thats not something that we can worry about.
Rob
--- End quote ---
Arthur:
Hello
Sorry for bumping this very old topic, but it has a lot of info in it on which I have new questions. Also my last project was in it, which was also peugeot and looks a lot like what I'm doing now. Also this info could be nice for the archives I think.
About (semi) sequential injection without camsinc:
Peugeot uses flywheels on which the 1st tooth is 120 deg before tdc. So it would be logical to take 60 deg btdc and teeth 10 and 40 as triggers, right.
Actually I have a TU engine now with BE4r gearbox. On this gearbox the sensor is in a different place (2 teeth) so you need 60 deg and 12, 42 trigger as trigger teeth. So for BE4r 1st tooth is 132 deg btdc. (22 teeth)
Now I see that Vems recommends 80 to 60, max 40 deg before TDC for the trigger. But why is 120 deg with triggers 0 and 30 not allowed? Wouldn't this mean the injection starts at 120 before tdc making 100% sure you inject on closed valves? (assuming inlet is closed 60 deg after BDC)
Does this mean I can play with this 132 degrees as long as the total is 132 degrees?
132 degrees with trigger 0 and 30 --> inject at 132 btdc (I guess it needs at least some time to calculate)
60 degrees with trigger 12 and 42 --> inject at 60 btdc
90 degrees with trigger 7 and 37 --> inject at 90 btdc
IMO it would all work. Let's say I take 132, 0, 30 and the inlet valve opens 10 degrees btdc. This would mean injection starts 132 degrees btdc and only when the pulsewith exceeds the time it takes for this 122 degrees to pass, it will be injecting on open valves, which doesn't hurt because this will only happen at high rpm and WOT anyway.
Isn't injecting as far btdc as possible the ideal way to inject sequential without camsinc and without worrying you inject on open valves at low load rpm? :-\
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