The ECU – the holistic approach

Thursday, February 21, 2013

Tags :  electronics

I don’t know about you but whenever I hear someone talking about the ‘holistic’ approach I tend to recoil with concern. Perhaps it is a reminder of my youth and the hippy 1970s, a time of much promise but little in the way of ultimate change. Or, more likely, it’s the arguably misplaced belief that individual parts of a system can only be explained by reference to the whole. So when somebody explained the concept of the ECU in a Formula One vehicle as holistic in concept I had to remain sceptical.

Thinking on though, in high-level motorsport perhaps the holistic approach is precisely what is needed. In medicine, ‘holistic’ normally refers to treating the entire person rather than the simple physical symptoms of a disease, and in a modern formula car the vehicle ECU is very much comparable to that of the brain in a human. First it receives coded messages from various sensors, the motor and exterior surfaces, and converts them into some kind of binary language. It then computes a response, sending messages back along the same communication system to other areas of the car, where it is decoded and acted on. In a way this mimics nature, and using the best available technology should be what motorsport at this level should be all about.

So it was encouraging when the individual concerned went on to say that racecar designers see a car as an entity, rather than in terms of separate systems that are subsequently bolted together. This latter approach is what we tend to find in road cars. No, the designer of a racecar looks at things differently and seeks to create an advantage over the opposition, which is why the system processors used in the latest generation of Formula One ECUs are the best available for the job and will never be found anywhere near any other type of transport application.

These processors were actually designed for network switching applications, and consequently the new Formula One ECU, the TAG320, controls everything on board the vehicle. The driver may steer the vehicle using a mechanical system (the steering wheel) and stop it using an hydraulic system, but everything else – throttle, clutch, gearbox, fuel pumps (of which there are many), differential and all the data passing back and forth – is controlled by the ECU. So while there may be many other boxes around the vehicle (including one at every corner taking data to and from each wheel system), all these are connected to the central ‘brain’ of the system via four wires – power, ground and two CAN lines.

But while the latest ECU, in use for the 2013 Formula One season, will work faster, handle more data and offer more control power than the previous version, the true benefit may not be visible until the start of the first race. You see, the older ECU’s architecture was such that you could never be absolutely sure that certain engine input/output data was not being used to operate illegal launch or traction control strategies. By completely segregating every single application and limiting the input and output signals to a specific application, launch and traction control can be completely eradicated in future and any accusations of cheating consigned to history.

An holistic approach it may be, but at the same time it just might be the tonic that the patient requires.

Fig. 1 - 2012 Formula One ECU (Courtesy of Mclaren Electronic Systems)

Written by John Coxon

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