what is the proper step size for vehicle simulation?

[LIU FAN]

Hello,

I am doing vehicle simulation with sedan vehicle. A const motor torque was applied to the vehicle,  and the acceleration should  decrease  with the time because of the effect of AerodynamicDrag and roll resistance. However, when the step size of 1e-3 was applied, the acceleration and longitudinal force increase with time,  when 0.1e-3 was applied, the result is reasonable. During the process, I have switched the tire model type(Tmeasy or magic formula) and solver type, but it does not work. 

If I set the step size with 0.1e-3, the simulation cost too much time. For the common sense, the step size of 1e-3 can lead to a reasonable result, but it does not work in my simulation.

I would be very appreciated if you could give me some advice about this problem, thank you very much

[stefan]

And I also found the tire step size has little affect on the vehicle simulation, can I know the effect of tire step size in the vehicle simulation? 

thank you very much!

Best regards!