First, I hope you are not trolling me. I'll assume you're not, and perhaps this is useful for someone, but I think you should really read a book about how a port injected engine works, as this is really the basics.
This is where we clearly use different definitions, perhaps because VCDS/VAG-Com use another definition compared to what I'm used to.
You say "So at 7000 rpm, 17.14ms injector on time is 100% duty cycle" which is absolutely correct, but these 17.14 ms injector time is what is available per stroke, not necessarily meaning that you automativcally want to spray in all strokes?
No, 17.14 ms injector time is the total time available, as that is how long it takes a four stroke engine to complete a cycle at 7000 RPM.
Let's break it down for you.
7000 rpm means it takes 1/7000 minutes per revolution. Which is 60/7000 seconds per revolution. Which is 60000/7000 or 8.57 milliseconds per revolution.
A four stroke engine needs two revolutions to complete a cycle. The cycle consists of the four strokes.
This means the total time available is 8.57*2 or 17.14ms to spray fuel during every cycle.
Why would you want to continue to spray another 17.14 ms in the compression stroke, and then another 17.14 ms in the combustion stroke and then finally another 17.14 ms in the exhaust stroke?
What you wrote here is completely wrong, and that is not how a four stroke engine works. Read above for the calculation.
Furthermore, if you adjust the trigger/starting point of the injection to slightly before TDC between the exhaust stroke and intake stroke, you can have more injector time than 17.14 ms, and this will provide higher duty cycles than 100%, at least i my experience.
Unless you invent a time machine, there is no way the injectors can be on for more than 17.14ms at 7000 rpm in a four stroke engine, as that is how much time is available per cycle before the next cycle begins. See the explanation above.
The indicated duty cycle can be over 100% in two cases.
First case is a rounding error in the calculations.
Second case is if requested injector pulsewidth is used for the calculation without taking in account latency compensation. Then it is only requested pulsewidth, actual duty cycle can never extend 100%, as 100% means the device is on all the time. Short to ground if you will.
Here is a defenition I'm more familiar with.
http://www.igotasti.com/vBforum/showthread.php?661-Injector-Duty-Cycle-explainedTo put it as simply as I can, IDC is how much of the intake stroke the injector is firing and is represented in % of intake stroke. The IPW is how long the injector is actually open and is represented in milliseconds. So if your intake stroke lasts for 20ms and your IPW is 22ms, then your resulting IDC will be 110%This is completely wrong. Duty cycle is the percentage of the total time a device spends in the "ON" position. Whoever wrote that IDC is represented as a percentage of the intake stroke has no idea what he is on about
The rest of the things you wrote also make no sense at all. Please read what I say. If how I explain it is not good enough for you, please read a book on four stroke engines.
A. Graham Bell has a pretty good book.
