Mustangman, I think the question of whether an all-electric/electronic system can be made lighter than a hydraulic system is an interesting one. I suspect it could, but admit that I’ve never thought it through. I seriously doubt that electric motors with ball-screw mechanisms is the only way to activate the calipers with the necessary force and the necessary control. Researching various possibilities to accomplish that action might be the best place to start such a project.
I seem to recall discussing this on this board previously- a few years ago now. It took some digging but I rediscovered the original technology I brought up here back then. As expected, development has continued and the design is even more refined now. It is inherently mechanically simple and lightweight. It takes far less energy to accomplish the goal than the prior design. Take a look here- this is the future IMO:
http://www.dmg-berlin.info/page/downloads/Vortrag_Gombert.pdf
The research has been done a number of years ago by every major brake supplier. They ALL want this for various reasons. One is: you won’t feel pulsing in the brake pedal from bad rotors and bring it back for warranty (very sad reason!)
The best I saw was a caliper by Continental, I think, that had mechanical gain built into it from force on the pads. It looked pretty promising as it had a fairly small coil and iron core but that was 10 years ago and now its… nowhere to be seen?
The current crop (pun intended) fell back to hydraulic actuation because they couldn’t find a good direct-electric-apply alternative. The hydraulic parts were pretty well understood and evolved from normal ABS.
I doubt they quit working on direct-electric, though!
Did you look at the one referenced above? This concept was first shown a few years back but has evolved into a single wedge design. The wedge provides mechanical advantage needed to make direct electric work even on a 12V bus…
How old is that presentation? The awards were back in 2004.
^Well, one benefit of an electronically-actuated hydraulic system, is that it’s easier to have it revert to a mechanical hydraulic system in the event of failure. If you had dedicated electric actuation, you’d need to build an entire separate system for the event of electric failure…or “live with” a system whereby you can’t control your brakes if you get a dead battery–which most people (rightly so, IMO) would have a problem with.
And aircraft typically use hydraulics in their fly-by-wire systems. If it were possible to save much weight (while retaining sufficient redundant safety), Boeing and Airbus would already be doing it.
THAT’s it @TwinTurbo, I didn’t see your post when I made mine. I guess we were typing at the same time!
Over 10 years later and its nowhere to be seen. Maybe it didn’t work they way they thought it would. After all it IS VDO/Siemens and electronic systems supplier not a brake system supplier.
I’d guess @meanjoe75fan has the reason - hard to do a hydraulic backup fail-safe with electric brakes.
Turns out Siemans sold VDO in 2007, nothing about the electric brakes on the VDO web site now.