In addition to the normal spring which returns the throttle pedal to the normal position, an additional, much harder, spring is also engaged using an electromagnetic actuator.

The control circuitry actuates this additional spring using the data from the actual road speed (from the speedometer) and a set speed dial ( the desired speed limit, set manually).

So, when the speed of your vehicle is below the set speed limit the accelerator pedal is "soft" and a slight pressure is all that it takes to accelerate.

When the speed is near or at the set speed, the additional spring engages which means that it becomes harder to push down on the pedal. But in an emergency pushing down hard enough will make the pedal go down to the floor.
-- neelandan, Oct 01 2009

so the position of the pedal is still determining the power output, but the force necesseray from the driver to reach that position is varied? That would mean when i press down on the pedal to make the car go at velocity x while driving downhill, and then the road slopes up again the pedal goes slack? somehow i do not think this would be an intuitive interface.

Better to vary power output with the foot, while controlling speed with the hand (cruise control).
-- loonquawl, Oct 01 2009


Determining the speed limit could be done by the car using existing technology. Vauxhall (GM,Omega,>insert regional variant here<) have an option on the new Insignia that reads road signs for you, and displays them on a screen, just in case you didn't catch them (I'd provide a link, but I'll be damned if I can find any info on it on Vauxhall's site).
You could make the system read the speed limits rather than just blindly display them.
-- kaz, Oct 01 2009


There is a safety concern. Such a system would present a danger for those times it may be necessary to accelerate out of the way of an oncoming busload of drunken vegetarians.
-- tatterdemalion, Oct 01 2009


I believe this is not just a good idea, but intuitively correct.

If I'm going downhill I expect to use less throttle than uphill. Constant foot pressure would give constant speed.

So long as the system can only generate a reasonably small pressure (a vacuum actuator would be appropriate) then there is no concern that it would prevent the driver from accelerating when required. (+)
-- Twizz, Oct 01 2009


so cruise control but you have to keep your foot on the gas ?
-- FlyingToaster, Oct 01 2009


I would not want this in my car because I (like 97% of other people) like to drive over the speed limit.
-- DIYMatt, Oct 03 2009



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