We use LTspice to simulate the circuits.
It can be downloaded for free: https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

To make it easy all necessary models are summarized in the OSS.lib
Just copy it into the project folder and add the following command in LTspice (press „S“):

.include OSS.lib

History OOS.lib

• Version 0.1
• Stand: 02.01.2022

Included models

• Thyyristor MCR706A Source: ON Semiconductor (Now: Littelfuse)
• Diode UF4007 Source: http://ltwiki.org/index.php?title=Standard.dio

To create an ignition coil, you create a transformator. Add to inductivities (press L) L1 and L2 and then create a directive (press S):

K1 L1 L2 0.7

This creates the transformator K1 with L1 and L2. And the last number is the efficiency. 1.0 is an ideal transformator with no loss and 0.7 is a good approximation for a standard ignition coil.

LTSpice is not case-sensitive, so for the unit prefix „Mega“ you need to write 1000k or meg, because m/M stands for milli.

This is a first version of a LTspice simulation. It shows the CDI at the Vape 70-3.
The red curve is the voltage of the high voltage coil V1 and the green curve is the voltage of C3.

Its not perfect yet but it works.