thoughts about full sequential engine control without camsync

[Leonhard]

Hi,

I'm working on a Audi 5-Zylinder engine, original with distributor ignition and K-Jetronic injection.
Now using a 60-2 trigger wheel for primary trigger,EV14 injectors and 5 single coil setup (VW V5); there is no need for a distributor anymore.
Just to keep the distributor housing for secondary trigger, a (software)-solution without, came in mind.
 
Aim is to get any 4-stroke engine starting/running and synchronised without the need of secondary trigger.

Usually there has to be a camsync signal to get the right timing, to match the compression stroke TDC.
A running engine with disconnected camsync stays synchronised.
In this case the only thing would be: to teach VEMS detecting power stroke without camsync in starting mode.
 
First thought (simple):
 
switching between the two possible settings: start counting at first detected TDC, count up to 2-5 times TDC (tunable as much as needed) in starting mode.
If engine hasn’t started yet, switch to TDC + 360° crank angle and count again until rpm threshold exceeds.
 
Second thought (more tricky but faster):
 
to measure the different deceleration between compression stroke and exhaust stroke in starting mode,
within the angle between missing-teeth (e.g. 60-2 primary trigger) and TDC to look at.
The higher deceleration shows the compression stroke and that’s the TDC to start with.

What do You think?

[Erikk]

Another option is to Start in wastefire and when engine temperature is enough, try to switch over to sequential, if engine is about to stall do a phase-shift.

Just a thought.

[Leonhard]

yes, wasted spark and splited injection should get the engine started/running anyway,
just tying up -> knock sensor could be used to find the right phasing without stalling the running engine ;-)

[Mads Lund]

I agree with starting in wasted spark mode, when engine is running, finding cy 1 (of 1 and 4 on a 4 cyl) will be as simple as switching off injection on cyl 1 in one event. If the expected period time until next trigger tooth even is as expected do it mean we have a cylinder fire .. equal cyl 4 did ignite, and opposite, if periodtime is "long" did'nt we have a fire .. equal cyl was supposed to fire, but did'nt as we took awa the fuel.

Very simple logic, and to ensure correct timing can it be redone for after 10 engine revolutions again and again, and after 5 test's with same result, are we sure we have found cyl1 ignition event.