On 2007-12-22, Wes wrote:
"DoN. Nichols" wrote:

[ ... ]

Or are you saying that electrical power steering is (or can be
made) more energy efficient than the hydraulic power steering found on
most cars these days?

I don't know how the current technology works for sure so I'm assuming we
have a constant volume pump dumping flow over a relief valve. If so, then
electrics might make sense. At highway speeds with normal inputs to stay in
one's lane power assisted steering isn't needed with most vehicles. I'm
pretty sure your old enough to have operated a vehicle without power
steering.

Absolutely. As a matter of fact, almost all of my vehicles have
been without power steering -- with my favorite being the MGA which was
one of my first cars.

Of course, you can get a pretty light steering from even a
rather heavy vehicle with the proper amount of caster. Bot that is not
much help when a heavy vehicle with wide tires is stationary -- that is
when the power steering is a benefit.

With an electric system a torque sensor on the steering input shaft would
turn on the hydraulics for a few moments during low speed steering
operations or a need to make rapid wheel angle changes at speed.

O.K. That makes sense.

I wonder if a variable displacement pump would be equally effective?

Probably a bit more friction loss when not being actively used.
And the friction loss in the extra pulley, too.

Enjoy,
DoN.

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