Wes wrote:
"DoN. Nichols" wrote:


Electric steering is already coming in, saves a Hp on the
steering pump.

And where does that energy come from to power the steering? If
you say "the battery", then the next obvious question is "where does the
energy come from to charge the battery" -- and the answer there must be
"the engine" for the most part -- though I guess that you could put
alternators inside the wheels so braking would partially come from
energy being transferred to the battery.

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.

We used to have a Taurus that had variable-assist power
steering. The power assist would fade out until it was totally
manual at 45 MPH. The thing used to scare me because it
required a LOT of steering effort to change lanes, etc. on the
highway.

The control valve is mostly free-flow when not applying force to
the wheel, but the pump still circulates the fluid through the
whole circuit, and that burns some energy.
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.

I wonder if a variable displacement pump would be equally effective?
Too complicated. The new systems are totally electric, with a
torque motor attached near the bottom of the steering column.
No pumps, no hoses, no valves.

Jon