I’ve run into the first mechanical challenge.
Our crank is a 120 crank and ignition fires every 240 crank degrees so...
With only the crank signal, the only option is multi point injection, meaning it injects “X” number of times (X set by user), over a single 720 cycle.
Ignition can be setup to fire every 120, in this way it would fire at strange event timing throughout the cycle.
My concern is that one of those sparks will be going off part way through the compression cycle and there may be enough fuel (which is squirting throughout the cycle) to ignite when it shouldn’t.
Clearly that’s not a desirable scenario so....
Adding a single magnet to a CAM gear and adding a Hall effect sensor to the valve conver (front flat area), will allow the ECU to know where TDC following compression stroke is for #1 cylinder. From there the ECU works out the other ignition events for #2 and #3. As a result I can now run full sequential injection and ignition.
Thankfully, this isn’t a deal breaker, mounting the Hall sensor is easy and a non-issue. On the other hand, mounting the magnet on the intake cam gear, may be an issue.
I’m thinking this part through.
My first idea is a hole in the cam gear, 50 degrees before TDC (as installed, 50 specified as optimal by Haltech). Countersink the hole on the cam side of the cam gear. Use a small countersunk titanium bolt (M4 or M5) and a small magnet bonded to a locknut which goes on the non cam side of the gear, obviously red locktite here and significant torque.
Install a matching Ti countersunk bolt and nut 180 opposite the magnet to keep the gear in balance.
Measure, drill, and tap a hole in the valve conver that aligns with the radius of rotation of the magnet for the Hall sensor. Rotate motor so the magnet is aligned just below the tip of the Hall sensor. Screw in hall sensor until it “just” touches the magnet, back it off 1mm. Install lock nut with red locktite on Hall sensor and peen into place.
Bobs yer uncle, working cam sensor.
Thoughts?
