2013-11-06
This calculation will calculate the maximum slope on which a vehicle without converter will start, provided that the slip time is sufficiently long and the acceleration at the end of slipping is not too low.
Startability calculates what grade (column 7) the gears (column 1 & 2) can be used to start at. When you start with a converter the startability is at 80% converter.
To be able to start, VTC has some criteria’s that has to be fulfilled. For calculating startabillity:
Max. slip on the clutch 3 sec.
Min. acceleration 0.4 m/s2.
The result are shown in a table (from left to right):
Column 1 shows what gear the vehicle can start on.
Column 2 shows the gearbox ratio.
Column 3 shows the engine speed.
Column 4 shows max. slip time on the clutch. If exceeded, the clutch can burn. This is pre-set by VTC.
Column 5 shows the actual slip time.
Column 6 shows the min. acceleration that is allowed
Column 7 shows the actual acceleration for the vehicle.
Column 8 shows how much of the friction that is used between the road and the tyres. The 100 % is maximum that can be transmitted. By adding more weight on the wheels My will reduce.
Column 9 shows the grades where start is performed.
Column 10 shows the work that is being transmitted through the clutch. The more the clutch is being loaded, the faster the clutch wears out.