Simulink - Vehicle Acceleration 3b


1. Brief Information
This model combines the characteristics of the two previous models, simulating gear changing with switch elements and using the one dimensional look up table so torque can be specified as a function of engine rpm (this is for full throttle). The data is from the Porsche 944 (1983) drivers handbook.
Because the engine rpm have to be fed back to the look up table, the effects of gear changes need to be considered in the feed back loop so there are 2 switch elements in this loop. Again the switches are activated by velocity thresholds, 13m/s for 1st to 2nd and 19 m/s for 2nd to 3rd.
Overall ratios are given as 12, 8.5 and 3 (these are not correct for this car).
The 0 - 60 mph time s about 5.5 second in this model, which is too brief a time. For simplicity the equivalent mass was given as 1000 kg, which is too low.

The model diagram is shown below:

David J Grieve, 25th October 2006.