4569846498

360 Multibody Systems Approach to Vehicle Dynamics
Torque (Nm)
Dimensionless
450
400
350
300
250
200
150
100
50
0
10
9
8
7
6
5
4
3
2
1
0
0
Fig. 6.35
Boost torque
NA torque curve
Total torque
0 1000 2000 3000 4000 5000 6000 7000
Engine speed (rpm)
k1
k2
1000 2000 3000 4000 5000 6000 7000
Engine speed (rpm)
Empricial mean-state turbocharger model
The delays inherent in a torque converter are amenable to such modelling
techniques using typical torque converter characteristic data in a similar
empirical manner.
Once the physical elements of the system are modelled, the task of modelling
the driver behaviour is largely similar to that for path following
described later. In order to represent, for example, the effect of a driver using
the throttle to maintain a steady velocity through a manoeuvre a controller
can be developed to generate the torque shown in Figure 6.34.
A simple but workable solution is to model the driving torque T, with the
following formulation:
T K *(Vs Va) * STEP (Time, 0, 0, 1, 1) (6.21)
where
K a constant which is tuned to stabilize the torque
Vs the desired velocity for the simulation
Va the forward velocity of the vehicle, which can be obtained using a
system variable