One Prius owner’s tests results

Bob Wilson, one of the geniuses on the Prius Technical Group email list, with the use of an accelerometer claims he has managed to reproduce the 2010 braking issue. According to his findings when all the right conditions occur there is a 600 millisecond delay between the regenerative braking system and the stand friction braking system.

You can click on any of the graphs and see the in larger format.

Basically, what this shows is what we already knew. There is, in this case a 600 millisecond zone where the braking doesn’t increase (it doesn’t decrease either). Immediately after this the curve knees downward and the velocity of the vehicle decreases precipitously.

Again, this isn’t proof, per se, of anything we didn’t already know, just proof to confirm owners estimates the lag was about half a second long. Keep in mind, this is one test under one set of conditions and it is not necessarily indicative of what happen under different circumstances.

It’s clear that there is massive pressure for Toyota to address this issue and it’s clear to me that at this point, “education” isn’t going to cut it. They have to do something to change this lag time. From the reports I’ve read, new Priuses (made since sometime in December of 2009 to January of this year) have already incorporated a new set of ECU instructions that address this issue. More on that very soon.