Sunday, March 22, 2009

Weeling Project goes to Traction Control

Since the Weeling Project is now working, I like to extend it with the Traction Control feature.
The basic idea is to cut the torque each time the rear weel is spinning above a certain threshold (same threshold used for the blinking white LED).
I've done some researches and I found out that one idea could to reduce the engine torque is to cut one cilinder spark firing.
Let's start to understand how Yamaha R6 is working:


About the spark coil, I found:



Yamaha declare to use a CDI, this is what Wiki is teaching us:
In a CDI system, a charging circuit charges a high voltage capacitor, and during the ignition point the system stops charging the capacitor, allowing the capacitor to discharge its output to the ignition coil before reaching the spark plug.

A typical CDI module consists of a small transformer, a charging circuit, a triggering circuit and a main capacitor. First, the system voltage is raised up to 400-600 V by a transformer inside the CDI module. Then, the electric current flows to the charging circuit and charges the capacitor. The rectifier inside the charging circuit prevents capacitor discharge before the ignition point. When the triggering circuit receives triggering signals, the triggering circuit stops the operation of the charging circuit, allowing the capacitor to discharge its output rapidly to the low inductance ignition coil, which increase the 400-600 V capacitor discharge to up to 40 kV at the secondary winding at the spark plug. When there's no triggering signal, the charging circuit is re-connected to charge back the capacitor.

The circuit shuld be similar to the B-type:


threfore without additional information, I have to assume that inside the Yamaha R6 ECU four capacitors are available and charged at about 400V and ready to share their energy with the spark-coils (E = 0.5 x L x I2 = 0.5 x C x V2) when the fire should happen.

Tourque Control
One idea to control the tourque seems to be the disabling of one cilinder firing, seems that GripOne is implementing such strategy.

Looking around I found this connection for the Inductive Transistorized injection (so, not working on my R6):



Some useful links:
McLaren CDI
GripOne Manual

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