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RE: Race condition...

On Fri, 19 Mar 2010, Tony Gore wrote:

> Not on this one, but the original Toyota accelerator problem does appear to 
> have been a poor piece of software. It is normal when writing an engine 
> controller to take account of other inputs. Thus, if the brake is pressed 
> (in my days, detected by the same switch that puts the brake light on) then 
> you cut the fuel injection down to a small level to sustain combustion and 
> keep the engine ticking over and this also helps keep emissions down.
> In the case of Toyota, they do not appear to have done this, or if they 
> have, the conflict between the signals has been mismanaged. This is why the 
> engine can have full throttle and is not overridden by the brake. Modern 
> engines (especially in US cars) are more powerful than the brakes, and this 
> is why people are finding it impossible to stop the car in some 
> circumstances.

Hi Tony/

Is the Prius case that simple? It's a hybrid. I had assumed that the problems 
were probably associated with the hand-off between regenerative and frictional 
braking. Presumably it tries not to use engine braking at all? Don't these 
systems have a smooth electric restart for the engine and shut it down 
completely under braking?

I've never looked inside a Prius (currently riding a bike while I repair 
the Land Rover) but I did go to school with Cedric Lynch.

PS Are you going back into the wave power industry now it's taking off?


Denis A Nicole              WWW:   http://www.hpcc.ecs.soton.ac.uk/~dan
School of Electronics       Email: dan@xxxxxxxxxxxxxxx
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