With the addition of a turbocharger to our single cylinder KTM setup, Monash Motorsport has recently developed a Powertrain package which outputs over 30% more power and over 25% more torque when compared to the naturally aspirated setup. To help our drivers control this around a track, we have recently been testing Traction Control (TC) setups for use with our MoTeC ECU.
Generally speaking, the idea of TC is to reduce engine power when a vehicle loses grip. This can be determined by slip ratios, RPM rate of change or other recorded parameters. Engine power reduction can also be conducted in numerous ways; ignition retard, fuel cuts and ignition cuts being most popular.
We began by implementing Traction Control into one of our previous cars, M12, to prove the concept. After going through the logs from the 2013 F-SAE Australasia Competition, it was decided that simple front-rear wheel speed slip ratios would be easiest to use when determining slip. Testing suggested that ignition retard, with later onset ignition cuts, would help to reduce engine power.
Having acquired engine data related to ignition retard from our dynamometer, we used MathWorks software to develop data analysis tools to help display power output (Figure 1) and calculate percentage power reductions (based on ignition retard) for the engine we are using. A preliminary tune was calculated and uploaded. This was then taken to a track to help us better understand the closed loop parameters involved in tuning power output (namely ignition retard and cut control variables).
Figure 1: M12 Power Output Surface Plot
The MoTeC M400 has an inbuilt TC function, which we can tune to suit our needs. It operates with a PID control system and maximum power reduction tables for safety and driveability. Initial testing has proven effective and has improved our understanding of the parameter sensitivities and limitations.
It is with anticipation that we are now developing the software to suit M14, our latest generation racecar. With higher power and torque outputs than ever before, Traction Control may play a vital role in the handling and dynamics of our fastest car yet.