What's more is the suspension load during landing... judging from that picture, almost all the load is put on the front right wheel and tyre.
So now we land: once that wheel touches the ground, the traction control notices that this wheel (only this one so far) speeds up. The difference may be small of course as the car isn't off the ground for a long time. However, what is the TC supposed to do then? Power on and speed up the rear wheels to that speed? Or slow down as that wheel (as it's faster) seems to be slipping?
When it matters that short period of time when both rears are in the air I think that most important job for TC is to prevent overrevving of engine since diff will lock as much as adjusted so it can be that rev limiter than plays "last line of defense"...
Tomba wrote:So now we land: once that wheel touches the ground, the traction control notices that this wheel (only this one so far) speeds up. The difference may be small of course as the car isn't off the ground for a long time. However, what is the TC supposed to do then? Power on and speed up the rear wheels to that speed? Or slow down as that wheel (as it's faster) seems to be slipping?
Most likely apply power, because the shock loads on the gears could break them if they aren't under load.
Is the present TC system, where the engine misfires, the only TC system allowed in F1? Are there any more 'efficient' versions, in the gearbox for example?
It strikes me that with frequencies and harmonics in the intake and exhaust systems being spoken about more and more, that misfiring the engine is, perhaps, not the most efficient method of reducing engine power to the wheels.
I am not a technical expert, so go easy on me if I am missing something. These are my thoughts and observations on TC.
There are many ways to retard power to an engine. And that's what traction control is for, keep the engine from putting out maximum power for the time it has to be cut back. For instance you could cut the spark and fuel to selective cylinders, cut out one of eight cylinders, in a way you are reducing power by 1/8th. Or cut out one cylinder every second firing. Then you reduce power roughly by 1/16. So you see, that just by electrical commands, you can reduce power by selective levels, to the range desired for that moment. Or since the throttles are now controlled by a computer and drive by wire, partially close the butterflies. Or apply braking effort, that too has been tried.
But obviously, once you are past the time when traction control is desired, you want to get up to power as soon as possible. If you have some mechanical device reducing power, then it takes a few milliseconds or whatever for the butterflies to open, or the brake system to reduce pressure, and the pads to release. But one cool thing about just cutting the spark and fuel is that it immediately returns to full power as soon as the spark fires and the fuel is injected, immediately. The air is flowing through the passages and cylinders, the throttle valve is already wide open, all it takes is spark and fuel to make everything right.
One little side benefit is when the fuel injectors don't squirt fuel and there is no spark, the air sucked through the passages and cylinder give a cooling effect, if only temporary.
Its quiet an interesting subject is the ol' TC. I read some quite indepth articles a while ago, in Race Tech and Race Engine Tech I think. From memory the main sensors used were:
individual wheel sensors - for speed and vertical acceleration
steering input sensors
various accelerometers within the chassis
chassis speed sensor
GPS or similar
The basic strategy was not to entirely eliminate wheel spin but manage it in different situations. Some slippage is desirable as it maximises acceleration and gives the driver a greater measure of throttle adjustable chassis control.
Most of the traction control was initially achieved through reducing the ignition timing advance, or shutting down individual cylinders, or a combination of both. From what I have read recently the differential is now a major part of this control system to. The differential control can also be programmed to work under breaking as well as part of the same control package to.
The data acquisition systems can pinpoint the cars location on the circuit very accurately and individual strategies can be programmed for individual parts of the circuit, corners and I guess right down to individual kerbs.
With the money being thrown at these things it’s not hard to imagine that measuring a combination of circuit position and vertical acceleration of the front wheels and the car, they can easily identify its initial launch over the kerb. This in turn initiates a suitably controlled response that can easily achieve a soft reduction and the appropriate soft increase in power to minimise the instantaneous loads on the engine and transmission, while still maximising traction ocorner.
As an engineer I am incredibly impressed by what can, and is being achieved by these systems. How flexible they are and how they can be adapted to different driving styles, conditions and parts of a circuit.
However as an ex racer and F1 fan I hate the bloody things. I remember hearing (and since reading about) Senna's driving style, constantly feathering and reapplying power as he went through a corner, the engine constantly playing a staccato under his direction, while he was constantly assessing and reassessing just how much grip was available – absolutely amazing.
Finally it’s going to be very interesting to watch what happens when the standard ECU is introduced and to see who of today’s drivers have the real talent and car control. That day will be the day, in my mind, that F1 comes home and becomes truly a driver’s championship once more.
