Anyone know what a car's transfer function is, ie the dynamic response written as differential equations and diagrams, so a controller can be designed for it (as in the cruise control feature in some luxury cars)?(adsbygoogle = window.adsbygoogle || []).push({});

I mean, many of us are familiar with the torque curve, ie engine torque as a fuction of rpm, but what is the meaning of it in the context of a controller? For example: Say the car is running at constant speed v and the engine is running at constant rate f revs per second. From the torque curve we know the torque that corresponds to the given rpm, and therefore this torque balances the wind resistance and other frictions.

But if you release the accelerator pedal, what would be the transient response of the car speed? We would instantly get less torque at the same rpm, so the graph would not be valid any more. What is the transfer function then?

An example torque curve:

http://myautoworld.com/auto/porsche/porsche-07-gt3/2007_911_GT3_Torque_Curve-US.jpg [Broken]

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# Car transfer function (from accelerator to wheels)

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