Think about the operation of a relay, would you expect contacts to slowly move together as you increased the coil current? The principal is exactly the same for an electromagnetic injector; apart from the small amount of time spent transitioning to an open or closed state (which is not controllable in any useful kind of range), they are effectively a binary device; on or off. Just like a relay, injectors exhibit significant levels of hysteresis. Once they have opened they can be held open at a lower current since the magnetic circuit no longer has an air gap in it, and therefore the closing current threshold is much lower than the opening current threshold. This should explain why the valve position can not be controlled proportionally with coil current. Mike On 31 December 2015 at 02:00, John Ferrell wrote: > I have only been partially following this thread so don't waste too much > time with me. > I thought mechanical movement in the injector body was small. I would > expect the valve position to be the integral of the input signal. If > that is the condition it would be a failure condition for fuel flow to > be either full on or full off. > Feel free to ignore the comment all together. > > On 12/16/2015 11:53 AM, Neil wrote: > > Correct, but I'm surprised that it took that long. In some ways I > > should understand, as this is almost the bare minimum current that woul= d > > make it open (lowest I saw that would open it was ~1.4A, but I did not > > scope that), but I would've expected to see some movement, even if just > > a budge, starting earlier. Just surprising, or enlightening, I guess. > > > > Cheers, > > -Neil. > > -- > John Ferrell W8CCW > Julian NC 27283 > It is better to walk alone, > than with a crowd going the wrong direction. > --Diane Grant > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .