Ignition Trigger Delay???? Does it exist???
Ignition Trigger Delay???? Does it exist???
(OP)
I wonder has anyone ever come across a device that enables a simple shift in ignition timing?
What I mean is, some piece of circuitry that can be introduced on, lets say, a single cylinder motorcycle engine, whereby the user can quickly change ignition timing, via lets say a potentiometer.
I do realise it might be a tall order that such a device can cater for any single cylinder motorcycle engine, but at least for those that employ a simple VR sensor, (as opposed to a Hall effect).
I imagined that if the default static ignition was advanced mechanically, lets say by slotting the stator plate, and moving the ignition to a position past a realistic advance, then by somehow simply delaying the triggering electronically, it would let the user tune the ignition live.
I know certain ignitions trigger at a certain part of the VR sinewave voltage level, nevertheless, I though somebody somewhere would have by now created some device to enable this?
I know someone is going to say, "they have, it's called a digital ignition such as a Power Commander", but I'm thinking of something you simply place in line within an already existing ignition system, with only the static advance adjustment, as already mentioned, needing to be executed, to achieve the range of delays required.
What I mean is, some piece of circuitry that can be introduced on, lets say, a single cylinder motorcycle engine, whereby the user can quickly change ignition timing, via lets say a potentiometer.
I do realise it might be a tall order that such a device can cater for any single cylinder motorcycle engine, but at least for those that employ a simple VR sensor, (as opposed to a Hall effect).
I imagined that if the default static ignition was advanced mechanically, lets say by slotting the stator plate, and moving the ignition to a position past a realistic advance, then by somehow simply delaying the triggering electronically, it would let the user tune the ignition live.
I know certain ignitions trigger at a certain part of the VR sinewave voltage level, nevertheless, I though somebody somewhere would have by now created some device to enable this?
I know someone is going to say, "they have, it's called a digital ignition such as a Power Commander", but I'm thinking of something you simply place in line within an already existing ignition system, with only the static advance adjustment, as already mentioned, needing to be executed, to achieve the range of delays required.





RE: Ignition Trigger Delay???? Does it exist???
I though about using the charge time of a capacitor (aka condensor), but the effect would vary according to engine speed. This is because the charge time of the cap would be fairly constant, but the time offset required for 5 degrees for example, would be 833ms @ 1000rpm but only 278ms @ 3000rpm. So you would get little change at low rpm but big changes as the rpm climbs. Also not adjustable.
"I know certain ignitions trigger at a certain part of the VR sinewave voltage level, nevertheless, I though somebody somewhere would have by now created some device to enable this?"
If this is the way your ignition works you might be able to rig in a simple voltage divider circuit. You could use a pot in the circuit to provide the variability you want. Also be aware that it would cut the voltage at all points in the wave, so make sure you have still have enough voltage at low rpm to prevent misfires.
Another way to do this is rig up two triggers and switch between them. Not infinitely variable, but simple in principle.
And lastly I have seen distributors set up with a pick-up that can be adjusted from outside the case by means of a screw and thumb wheel. It is difficult to know where you are without using a timing light, but it does make adjustment easy.
ISZ
RE: Ignition Trigger Delay???? Does it exist???
Harleys in the thirties and forties and automobiles back in the thirties just moved the distributar housing to adjust the spark timing. The MCs used a twist grip and a cable to the distributor housing. The old cars generally used rods and bell cranks to move the distributor.
The old speeders on the railroads had a lot of mechanical advance and retard on the single cylinder two cycle engines. To reverse the operator would kill the ignition and advance the spark all the way. When the engine had coasted almost to a stop he would turn on the ignition. The engine would backfire and commence to run in the other direction. More than one biker and more than one peson hand cranking an early engine was injured trying to start the engine with too much advance when a backfire would send the kick starter or crank back at them.
It won't hurt to look at the bike to see if the distributor will be easy to move. It may be more dependable than a home brew electronic solution.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Ignition Trigger Delay???? Does it exist???
RE: Ignition Trigger Delay???? Does it exist???
I think they all did it by rotating the points plate as they had solid mounted magnetos normally.
Regards
Pat
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RE: Ignition Trigger Delay???? Does it exist???
I can't see how a manual adjustment, without any correlation to actual timing could be a significant improvement, overall, since the fixed delay must wind up compromising the performance at some rpm.
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
RE: Ignition Trigger Delay???? Does it exist???
It seems you are asking for an electronic ignition module. Unless you have perfect pitch, it would seem unlikely that you could tell the exact engine rpm by ear, so what kind of "fine tuning" could you do by a relatively crude hand adjustment?
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
RE: Ignition Trigger Delay???? Does it exist???
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
- delay adjustable in time
- delay adjustable in crank angle
- delay adjustable in time, different at different RPM.
- delay adjustable in crank angle, different at different RPM.
Mike Halloran
Pembroke Pines, FL, USA
RE: Ignition Trigger Delay???? Does it exist???
All eminently possible.
All would result in instant retaliation by CARB, of course.
Mike Halloran
Pembroke Pines, FL, USA
RE: Ignition Trigger Delay???? Does it exist???
The trick was to use a free running up-counter to measure the length of the 'previous' points cycle, and have it count down to a number representing 2ms, not zero. It required two such counters, working in alternation. The CMOS breadboard worked as designed on the bench. The intended recipient car had to be junked for other reasons before I got around to installing it, and by then, none of the new cars had points anyway.
Nowadays, you can build whatever behavior you want into a little box with a microprocessor in it.
Mike Halloran
Pembroke Pines, FL, USA
RE: Ignition Trigger Delay???? Does it exist???
To store and delay:
> ADC with lots of input protection
> Waveform memory
> FPGA control circuit
> DAC with lots of output protection
> power source/regulator
If other inputs are required, that's just more ADC inputs, and probably going to a microcontroller, like an Arduino: http://www.sparkfun.com/products/9949
Here is someone who used it for their car ignition controller:
http://thedeltaecho.wordpress.com/2jzduino/
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
Mike, what I want is a means to mimic the old time advance/retard cable unit which mechanically rotated the distributor, but by means of a device which is added INLINE to the trigger sinewave output from a VR sensor, whereby the said sinewave can be temporarily restrained, before being released after the dialled in delay time has elapsed.
"On a not unrelated note" Mike, with your 2ms saturation time set up, did you mean that the 2ms was a constant, no matter the engine speed was? Would that be sort of like a variable dwell angle in reality?
"then maybe no one else sees a benefit" nor did these blokes who were in the know:) quite amusing (the first 5 quotes)
http://ifaq.wap.org/computers/famousquotes.html
RE: Ignition Trigger Delay???? Does it exist???
Even if the micro didn't have analog inputs. I've used 555 timers to 'read' analog pots with an 8741. Things like that are much easier now.
Mike Halloran
Pembroke Pines, FL, USA
RE: Ignition Trigger Delay???? Does it exist???
"a device which is added INLINE to the trigger sinewave output from a VR sensor, whereby the said sinewave can be temporarily restrained, before being released after the dialled in delay time has elapsed." which I've already described, and provided links to devices that you can build.
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
Cheers
Greg Locock
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RE: Ignition Trigger Delay???? Does it exist???
TTFN
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RE: Ignition Trigger Delay???? Does it exist???
RE: Ignition Trigger Delay???? Does it exist???
Is this a "Trials" motorcycle?
RE: Ignition Trigger Delay???? Does it exist???
RE: Ignition Trigger Delay???? Does it exist???
Cheers
Greg Locock
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RE: Ignition Trigger Delay???? Does it exist???
Can I quote you on that in another forum on another site.
Regards
Pat
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RE: Ignition Trigger Delay???? Does it exist???