DC-CDI based on ATMEL 89c2051.
A great job from Thomas Schattat from Germany.
Synoptic.
Principle.
Designed for a TT600R, this ignition produces itself the high voltage necessary to the load of the CDI capacitor (Capacitive Discharge Ignition). It dont need a alternator.
Circuit MC34063 "DC-DC converter control circuit" switch on/off the primary coil of the L1 transformer at 25KHz.
At the secondary of the L1 transformer, one finds the primary
voltage
multiplied by 10 then rectified by the B1 bridge. One get approximately
160Vcc which charges the C2 capacitor.
The energy in the spark is E=0.5 * C * U*U (joules,farad,volts)
Exemple:
At 10.000 rpm, the time available to charge a capacitor of 1uF is 6ms
To goes from 0 to 220volts (so to say 110volts average) in 6ms, it need:
E=0.5 x 1 x 10-6 x 110²
E=6050 x 10-6 = 0.006 joules
In 1 second (1000ms): 1000/6 x
0.006 = 1 joule
1 joule/1second = 1 watt
The positive shape of the pickup signal is shorted by D12
diode.
Only the negative part of the signal is used. The dividing bridge R16
R18 fixes the potential at AIN0 entry to 2.9volts.
D9 and D10 protects the entry from overvoltage.
The negative pulse is detected by the processor, that
calculates the delay necessary then provided zero volt to Q1 transistor.
The transistor become on and blocks the inverter circuit MC34063 so
that it does not produce any more High tension and trigger at the same
time T2 thyristor.
The thyristor discharges the charged capacitor C2 in the ignition coil.
The coil amplifies this tension by approximately 100, and provides
20.000volts to the spark plug which generates a spark.
Software.
| Source | Excel | |
| DC-CDI with ATMEL for TT600R |
cdi8.ZIP | mapXLSB10.XLS |
Download: right click / Save link as...
Also the syntax may not completely be accepted by your compiler and you may have to tweak a bit.
Functions.
RPM Limitation:
Over 8000 RPM, the ignition is switch off (line 54)
Under 588 RPM, the ignition is switch off (line 56)
Advance calculation:
Between the maximum and the minimum RPM, the ATMEL measure the duration
between two pick up pulses in 400us units (four hundred microsecondes)
to deduce the speed engine in RPM.
According to the speed, the processor calculate the position in the map. (line 59)
At this position of the map (a 256 values table, lines 105 to 116) the ATMEL found a delay value.
Then the ATMEL is waiting during this delay [in 100us units
(hundred microsecondes)].
At the end of the delay, a 400us duration pulse is sent to the
thyristor.(line 90)
Duration of the spark:
The duration of the spark cannot be adjust on a CDI, it depend of the
capacitor value and the coil value. After all we can adjust the
duration of the pulse that trigger the thyristor. This pulse duration
can be change line 85, but without impact on the spark duration.
Modification:
You can change directly the values from the table (lines 105 to
116)
And don't forget: The timing delays in the assembler program are based on a pickup coil mounted about 58° before highest piston position, different bikes may have different positions here!!
Programmation.
Assembling the .ASM file in a .HEX file with a assembler:
IE:
Schéma.
| Atmel DC-CDI for TT600R |
Schéma | Eagle v4.11 | Composants |
| Schéma.PNG |
Schéma.SCH |
liste.txt |
Printed Circuit Board.
| Atmel DC-CDI for TT600R |
Circuit imprimé.PNG | Eagle V4.11 |
| Cuivre
& composants.PNG |
Cuivre
& composants.BRD |
Transformer.
L1: naked transformer available at Conrad Electronics
order #:51 66 43
Primary coil : 25 turns 0.5mm wire
secondary coil: 160 to 180 turns 0,15mm wire
Important : Leave a little air-gap between the 2 metal parts by slipping a bit of paper for example.
Realisierung
