Honda Car Forum

"George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote
C wrote
> >Re the power requirements of a strictly electric-drive PS system:
> >After seeing Boz's post on the no hydraulic, all electric motor driven PS
> >system, I googled. As it turns out the claim is the all electric-driven PS
> >system is more fuel efficient by around 5%.
> >http://ca.autos.yahoo.com/030820/11/ugrz.html claims its simpler too. (And it
> >does sound simpler: No fluid hoses. No pump. No belt.)
> >
> >A fuel savings of 5% does sound reasonable (though puny). I forgot how
efficient
> >electric motors are. So if the PS motor is not running all the time, like Boz
> >and Mike suggested, yes there's a fuel savings. I suppose this all
> >electric-drive PS system relies heavily on electronics. I guess the parts are
> >probably more expensive to replace but last longer(?) and help other parts to
> >last longer, like a lot that's gone electronic over the decades with cars.
>
> I'm still awfully wary of EMSs.:-) It always seems to me that the more
> sophisticated they make household appliance controls, the less reliable
> they become... dishwashers, washing machines etc.

While I have a less experience than you in car specifics (among other areas), I
have the same feeling about this EMS (electric motor steering?). For me, I think
it might be prejudice against change and maybe having to learn something new
(all the electronics in the EMS).

On the surface, the link above certainly seems to me to make some good points
about the simplicity of EMS vs. a hydraulic PS system.

On the third hand, I've also seen at least one media report that talks about all
the electronic gadgets in loaded, new cars and how these cars may be spending
more time in the shop, not less, compared to cars 15 years or so older.

I'm keeping an open mind on EMS and will keep studying it, especially maybe its
reliability reports in something as simple as Consumer Reports annual April car
system reliability tables.

Of course, over the last few weeks, having recently nailed down and fixed all
the itty-bitty oil leaks on my 1991 Civic LX; given its great fuel mileage; now
also having my fancy, "proven" crankshaft pulley holder toy... uh, tool; and
looking at, at worst, a new clutch in the next few years, I'm thinking the new
Toyota Echo I have been eyeing is now five years or more away. We'll see if
Toyota has EMS by then. Or maybe Honda will wise up and start making Civics with
1.5 liter engines again and EMS.

On Sun, 27 Jun 2004 15:32:23 GMT, "Caroline"
<caroline10027remove@earthlink.net> wrote:

>"George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote
>C wrote
>> >Re the power requirements of a strictly electric-drive PS system:
>> >After seeing Boz's post on the no hydraulic, all electric motor driven PS
>> >system, I googled. As it turns out the claim is the all electric-driven PS
>> >system is more fuel efficient by around 5%.
>> >http://ca.autos.yahoo.com/030820/11/ugrz.html claims its simpler too. (And it
>> >does sound simpler: No fluid hoses. No pump. No belt.)
>> >
>> >A fuel savings of 5% does sound reasonable (though puny). I forgot how
>efficient
>> >electric motors are. So if the PS motor is not running all the time, like Boz
>> >and Mike suggested, yes there's a fuel savings. I suppose this all
>> >electric-drive PS system relies heavily on electronics. I guess the parts are
>> >probably more expensive to replace but last longer(?) and help other parts to
>> >last longer, like a lot that's gone electronic over the decades with cars.
>>
>> I'm still awfully wary of EMSs.:-) It always seems to me that the more
>> sophisticated they make household appliance controls, the less reliable
>> they become... dishwashers, washing machines etc.
>
>While I have a less experience than you in car specifics (among other areas), I
>have the same feeling about this EMS (electric motor steering?). For me, I think
>it might be prejudice against change and maybe having to learn something new
>(all the electronics in the EMS).

EMS (Electro-Mechanical Systems) in general - thus the reference to
dishwashers etc. The old systrems with the rotating dial worked almost
forever; the new umm "programmable" systems always seem to be failing, with
replacement of the entire control unit for ~$300. the only repair option.

>On the surface, the link above certainly seems to me to make some good points
>about the simplicity of EMS vs. a hydraulic PS system.

Yep and it would be nice when working on the car to err, lose the pulley,
hoses and belt.:-) something always seems to get in the way of something
you want to do. OTOH hydraulic systems are now well understood and last
very well with very little leakage problems.

There are some good articles on the Web, with a good illustration here
http://www.egr.msu.edu/autoweb/Class...nformation.htm
of Honda's EPS as used on the NSX/s2000. The biggest potential problem I
see with it is mechanical wear and lubrication to avoid it. The obvious
advantage of a hydraulic system is that the rack is pushed by a hydraulic
ram so there is very light stress on the rack & pinion and related
bushings. I can foresee, e.g. people who go to bigger wheels/tires, taking
a factory EPS beyond its design limits easily and breaking the
electro-mechanical drive.

>On the third hand, I've also seen at least one media report that talks about all
>the electronic gadgets in loaded, new cars and how these cars may be spending
>more time in the shop, not less, compared to cars 15 years or so older.

Yep and from what I gather, VW is a prime example here with all their
glitches in the electronic gadgetry in recent models. I also remember the
days when you could limp home for hours with a failed/failing alternator or
broken belt - all the battery needed to do was supply spark to the engine -
no more.:-(

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

"George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote
C wrote
snip but comments noted
> >On the surface, the link above certainly seems to me to make some good points
> >about the simplicity of EMS vs. a hydraulic PS system.
>
> Yep and it would be nice when working on the car to err, lose the pulley,
> hoses and belt.:-) something always seems to get in the way of something
> you want to do. OTOH hydraulic systems are now well understood and last
> very well with very little leakage problems.

True, from what I've seen. I note I'm not re-building my 13+ year old power
steering pump anytime soon, after all. Seems the silly leaks were all fixed by
more basic seal replacements, like valve cover grommets (ouch). We rarely see
reports of power steering leaks here at the newsgroup, too.

> There are some good articles on the Web, with a good illustration here
> http://www.egr.msu.edu/autoweb/Class...nformation.htm
> of Honda's EPS as used on the NSX/s2000. The biggest potential problem I
> see with it is mechanical wear and lubrication to avoid it. The obvious
> advantage of a hydraulic system is that the rack is pushed by a hydraulic
> ram so there is very light stress on the rack & pinion and related
> bushings.

After briefly studying the drawing at the above site and considering how
power(-assisted) steering rack and pinion systems work, I agree with you. In
sum, an EMS has more mechanical gearing power transmission than a hydraulic
system. That extra mechanical gearing power transmission will require more
design "attention."

> I can foresee, e.g. people who go to bigger wheels/tires, taking
> a factory EPS beyond its design limits easily and breaking the
> electro-mechanical drive.

I am figuring the engineering design factored this in. E.g. the gears are made
of higher strength (fatigue and yield) steel than the ordinary, hydraulic PS
rack and pinion? No idea.

Time will tell, I suppose.

These net reports are certainly optimistic about the trend being towards EMS
power steering.

Maybe some manufacturer bias is more than a wee bit present.

(And a 42 volt electrical system, per the site above? I wonder if those students
aren't being a bit optimistic as they talk about "engineers" wanting to drive
the water pump and A/C compressor with electric motors. Surely this has been
considered in the past. I will have to think about why such a switch has not
been made.)

> >On the third hand, I've also seen at least one media report that talks about
all
> >the electronic gadgets in loaded, new cars and how these cars may be spending
> >more time in the shop, not less, compared to cars 15 years or so older.
>
> Yep and from what I gather, VW is a prime example here with all their
> glitches in the electronic gadgetry in recent models. I also remember the
> days when you could limp home for hours with a failed/failing alternator or
> broken belt - all the battery needed to do was supply spark to the engine -
> no more.:-(

:-)