Launch Control
A fine thing, an optimal acceleration, one must in principle only step on the gas. Perhaps with a view to wear not too often. Most of the time you look at the start-up behavior. Obviously the software is optimized to avoid
too much slip on the wheels.
However, we would like to follow up the question what the appropriate switching points would be, both for gasoline and diesel engines. Clearly, it is about the adjustment to the performance curve in relation to the
transmission from the lower to the higher gear.
The power is decisive and explicitly not the torque, because in the performance not only the torque, but also the time factor is included in the acceleration in the form of the speed. E.g. most torque can an electric motor
have without rotating. Force alone helps little, force per time is essential.
Admittedly, it is an older utility motor, shown here with only five gears, to keep the matter clear. But that does not change the principle. You would have to take the values of your vehicle anyway, in order to find the ideal
switching points. Then there is also no difference for a diesel in the procedure:
| Switched is from . . . |
| a) 6000 in the third to 4700 rpm in the fourth gear |
| b) 5500 in the third to 4300 rpm in the fourth gear |
| c) 5000 in the third to 3900 rpm in the fourth gear |
Of course, values would also be possible in between, but then the example is no longer so vivid. For here it should be clear that in this case the solution b) is the right one, because the performance is
best saved into the next gear. There is therefore no general rule, e.g. shifting always at maximum speed.
By the way, this would have to be determined individually for each gear, since the situation according to the above diagram from the fourth to fifth gear is certainly different, because of the smaller distance
there. And we might assume that these considerations play a part in the installation of the Launch Control in a sporty vehicle.
Now let's assume a performance characteristic, as it is in this diagram, a deceleration of the charge pressure over a speed band of 1200/min. The next picture will show you how to make the ideal transmission.
However, you need ten gears that are to be switched automatically and for maximum acceleration and not for overdrive. Then the ideal would have been reached, that the power would be optimally converted into
acceleration. Even in this case 300/min before the maximum speed would also be switched. 03/17
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