Rotary injection angle calculation

EMU PRO
1

Hi,

I would like to better understand how the ECU internally defines and calculates the injection angle on rotary engines.

  • Is the reference for the injection angle based on eccentric shaft degrees or crank-equivalent degrees? (360° for one cycle of ONE rotor phase and. 1024° for a full rotor cycle)

  • When using End of Injection (EOI) control mode, does the ECU calculate the start of injection relative to the rotor phase (TDC compression), or is it purely based on the eccentric shaft position?

  • In other words: how does the EMU Pro translate the “°BTDC” values in the Injection Angle table for a rotary application?

  • And if possible, what exactly does “TDC” correspond to in this context — the leading chamber’s ignition TDC or something else?

I’ve seen different conventions between ECUs (Link, Haltech, etc.), and I want to make sure I understand how EMU Pro defines it before finalizing my SOI/EOI mapping.

thanks and br

2

Hi,

The only difference between piston and rotary engines in PRO is that the engine cycle is 360 degrees instead of 720 degrees.

One rotation of the crankshaft is 360 degrees in the ECU.

Ignition and injection angle are relative to the configured TDC position.

TDC is just a reference point in the engine cycle that you configure. ECU doesn’t care where it is. You can set the TDC at any angle of the engine cycle, and the ECU will control ignition and injection relative to that TDC point. If TDC is at 100 degrees of crankshaft angle and you make 0 degrees of ignition angle, the coil will fire at 100 degrees of crankshaft angle.

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