MSefi.com read only forum (Jan.15,2018)

Long story short, I'm considering a Megasquirt system for a very unique engine application. Not going into detail about it as it tends get way off subject.

My problem is the crank position sensor. It's not possible to mount a rotating pickup wheel on this engine, so I was thinking I may be able to get a linear reading off the piston itself.

Would it be possible to run the engine off of a reciprocating pickup? The main issue I see with it is what happens at bdc and tdc when it changes direction.

Since you're hesitant to discuss technicals.
If it uses mechanical valves, perhaps sensors there... say Hall effect sensors in parallel triggered by valve motion?
Pressure sensing, piezo-electrically, intake pulses?
Optical sensing on something external which moves at a fixed ratio with the crankshaft?

The current code (and possibly hardware) won't handle a linear position sensor.

I suppose you could set up a Hall effect sensor that just triggered at TDC. Theoretically, this would be sufficient to run a single cylinder.

the reason the sensor cant rotate is there are no rotating parts, no crankshaft, no cams

So the MS could be set up to simply fire when it passes a single pickup? I assume this would be sacrificing the ability for any kind of timing adjustments.

suprant0010 wrote:the reason the sensor cant rotate is there are no rotating parts, no crankshaft, no cams

So the MS could be set up to simply fire when it passes a single pickup? I assume this would be sacrificing the ability for any kind of timing adjustments.

It can and there is some measure of timing adjustment possible - it's similar to a distributor trigger.

Matt Cramer wrote:

suprant0010 wrote:the reason the sensor cant rotate is there are no rotating parts, no crankshaft, no cams

So the MS could be set up to simply fire when it passes a single pickup? I assume this would be sacrificing the ability for any kind of timing adjustments.

It can and there is some measure of timing adjustment possible - it's similar to a distributor trigger.

i think this will do the trick...would I be able to put 2 pickups and run 2 cylinders this way, 1 pickup for each cylinder?

Possibly using the MicroSquirt "twin trigger" mode.