The brake actuator, which incorporates the high-pressure reservoir (accumulator) and pump, is buried behind the inverter. It uses positive brake fluid pressure, and there's no dependency on engine intake manifold vacuum (no vacuum when the engine isn't running!) There's a copy of the 2006 Prius Service Manual at http://www.selidori.com/tech/prius/DOC/Tech2006/ - see page 211 of the Brake Control section.
Thanks Mike. There is a Prius at a salvage yard here and the engine is out of it. I was thinking of pulling it as a possible part for an EV.
Yeah, I'm seeing that now. Interesting design. I take it that the pump runs off the hybrid pack vs the 12V then?
It requires some kind of computer to drive it. It is not just an accumulator pump, it is about the most complicated brake pressure provider/modulator possible. There's something like 40 connections between it and the antiskid ecu. I'm not saying it can't be done, but I think you are looking at person-weeks or months of time to get something to work reliably. If it were me, I would go low-tech, as in the $350 12V vacuum pump + motor that would run a conventional power booster.
