Page 2 of 2
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 3:35 pm
by russian
Yes, this is my concern - I was playing with my engine this weekend and I have seen on my analyzer how far the timing was while I was using the '1 event per revolution' algorithm that I got scared and switched back to the 'handle all events' algorithm.
Again, this is only a _concern_ - I do not know the exact value of timing in-accuracy which would still work. 10 degrees? 20 degrees? Is it only while cranking, or would it also matter while revving?
I would try to allocate some time and actually gather some data on my live engine, that would actually be interesting to look at.
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 4:00 pm
by settra
well. the "Sure" thing, is at least when cranking, that if i where to control the ignition as well, i would have a problem...
but since the injection, is anyway happening at a closed valve ( i think?? ) and since, during crank, i will anyway supply more fuel, i dont think there will be a big problem..
the reason i want 1 point per revolution, is becouse, with the AVR i will use (Arduino, atmega328), it will be MUCH simplier to handle, than with more points... (especially, determining which point is before which cylinder TDC...)
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 4:17 pm
by russian
settra wrote:with the AVR i will use (Arduino, atmega328)
offtopic: it seems like there are ~128 Arduino ECU projects right now, whoever would start a community and unite this force can get a cool project. With my stm32 approach I was shocked to find other people trying the same thing on the same platform and it seems like we are now helping each over.
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 4:35 pm
by settra
yiap. IF i succeed, i will try to make a webpage about it, because, although there are many projects, the documentation, is very little...
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 6:45 pm
by Fred
settra wrote:so you mean, that etc:
the first cylinder will have good timing,
but then, when its time to spray the second, or even worse, the 4th, the rpm , will have change so much, that it will be dificult to get the correct timing??
No. Meanwhile russian answers yes. This is how we separate men from boys and products from toys.
Re: calculate RPM and crank position,with distributor signal
Posted: Thu Jan 23, 2014 7:06 pm
by settra
No, in what part?? you mean that it will not work at all? or you mean "no there wont be a problem" ??
Re: calculate RPM and crank position,with distributor signal
Posted: Fri Jan 24, 2014 12:37 pm
by settra
so, no other sensor of cam/crank located on the engine...
BUT. i was able to monitor the distributors signal, by manually turning the engine, by the camshaft....
turns out, that , the signal is constant 12v (or you can invert it. same results), AND goes LOW, 4 times, inside every camshaft rev..
so 4 pulses, equal cam rev, or 2 crank revs...
so... by that signal alone, i suppose i cant get EFI to work, becouse, i will know, that one cylinder is before TDC, BUT , i will not know, which one... correct????
i will need to figure a way, to know, the 1st cylinder's TDC seperatly??? any good way to do so???