Vermes
Advanced Member level 4
It is a project of useful device – car digital ignition distributor module. The purpose of this design was to create a system which turns on each coil (while the ECU controls the moment of ignition).
How it works:
The system monitors the camshaft position, so it can get the information on which cylinder the ignition should occur. It waits for a signal from the ECU and then turns on the coil.
Construction:
Position of the camshaft is checked by a converted distributor rotor and valve dome. There are Hall Effect sensors glued to the electrodes of the dome, and there are few magnets on the distributor rotor. After that, the signal is amplified using a differential operational amplifier and the signal enters the AND gate input. The second input of the gate is controlled by the falling edge of the signal from the ECU. Then the signal turns on the RS flip-flop (next turn on automatically turns off the previous one), which, together with the leading edge of the signal from the ECU turns on AND gate which in turn controls mosfet by the driver.
Here are pictures of double-sided board made in photo-chemical method.
In the box on the left you can see heat sink with mosfets, in the centre – control board and on the left – small board of the power supply (+12V and +5V). The blue element in the centre is the relay, which turns on the ECU and the ignition module. There are four red diodes indicating the ignition on each of the cylinders.
The distributor rotor with magnets.
Processed dome with small Hall Effect sensors.
And a video:
Link to original thread - Cyfrowy rozdzielacz zapłonu do samochodu