Power Steering in the Prius.

[ronhowell]

Hi All,

New Prius owner here, but learning every second! Is it true that the Power Steering in the Prius is "electronic"? During my younger engineering days "electronic" signified light current , whereas "electrical" signified heavy (i.e. Power) current. Since I was in the Aero engineering fraternity, all fly-by-wire aircraft I was familiar with used electronic signaling but the muscle to move flying surfaces was provided by hydraulic actuators, either static or dynamic. Of course the forces being dealt with were quite high.

So is the Prius power steering purely electrical throughout, or does it involve electrical signaling but hydaulic actuation? Just interested!

[qbee42]

That definition of electronic and electrical is not commonly used. Electrical indicates that electricity is used, where electronic adds some sort of electrical control system, which now-a-days usually means transistors or some sort of chips. The steering in the Prius is done via an electronic drive system; no hydraulics are involved.

Tom

[Danny Hamilton]

<div class='quotetop'>QUOTE(qbee42 @ Oct 30 2007, 04:10 PM) [snapback]532578[/snapback]</div>

That definition of electronic and electrical is not commonly used. Electrical indicates that electricity is used, where electronic adds some sort of electrical control system, which now-a-days usually means transistors or some sort of chips. The steering in the Prius is done via an electronic drive system; no hydraulics are involved.

Tom
[/b]

In other words, using the OP definition, the Prius power steering is both electronic and electrical.

Of course I suppose that all depends on exactly how many amps you use to draw the line between "light" current and "heavy" current.

Is there an official "current" limit for electronic vs. electrical, or is it left up to the speaker? In that case, it could be just electrical, or just electronic.

Since something (the wheels) have to actually "move", I suppose the best description would be electro-mechanical. I assume that magnetic force is used to convert the electric power into the mechanical force, so perhaps a reasonable description is electromagnetic?

I guess it all comes down to what you are trying to describe about the system. Whichever description you use, it looks like qbee answered what the OP wants to know. No hydraulic actuation.

[hobbit]

http://techno-fandom.org/~hobbit/car...ng/800/eps.jpg for a
shot of the torque sensor, control electronics, and nylon drive gear
that the motor talks to. No hydraulics needed -- the motor circuit
is fused for something like 50 amps, and could easily break your arm
if you were on the wrong end of it. In fact EPS systems do need
fairly high peak power requirements, albeit infrequent, so other
manufacturers are starting to implement higher-voltage systems for
them. The HiHy, for example, uses a 42-V DC/DC converter hung off
the hybrid battery just for the purpose.
.
_H*

[kohnen]

<div class='quotetop'>QUOTE(Ron Howell @ Oct 30 2007, 03:28 PM) [snapback]532563[/snapback]</div>

Hi All,

New Prius owner here, but learning every second! Is it true that the Power Steering in the Prius is "electronic"? During my younger engineering days "electronic" signified light current , whereas "electrical" signified heavy (i.e. Power) current. Since I was in the Aero engineering fraternity, all fly-by-wire aircraft I was familiar with used electronic signaling but the muscle to move flying surfaces was provided by hydraulic actuators, either static or dynamic. Of course the forces being dealt with were quite high.

So is the Prius power steering purely electrical throughout, or does it involve electrical signaling but hydaulic actuation? Just interested!
[/b]

Yup! Back in the days when an active device (transistor or vacuum tube) couldn't handle enough power there was such a distinction.

Now, since all of the motor power of the Prius is transistor controlled, it's not only an electric car, but an electronic car.

By today's standards, it is very reasonable to call the power steering electronic, because the actuator is an electronically controlled dc motor.

[ronhowell]

Many thanks to all, esp. Hobbit and Kohnen for their illumination of the question. I was wondering if the Prius system was operating off the 12V circuits or a fraction of the higher NiMH battery circuit. If it is similar to the HiHy that Hobbit describes I assume the latter applies.

Does the steering rate sensitivity vary with actual road speed? I can't say I have noticed any, but I'm still running the car in anyway. Only 319 "smooth as silk" miles so far.

Ron.