On May 15, 6:23*pm, "RogerN" wrote:
"Jim Wilkins" wrote in message

...
On May 15, 10:59 am, "RogerN" wrote: ...
Seems like if metalworking skills and homebuilt aircraft skills were
combined the people could make an automobile better than the automakers
are
providing for us.
RogerN

\
\I have worked on recent electric vehicle development projects and
\seriously doubt that a vehicle which meets regulations could do
\much better. If you don't need to meet them a car chassis from 1910
\(recent experience) and a design top speed of 40 MPH or less might be
\able to achieve 100 MPG or its electric equivalent. The first cars
\were built like buggies or bicycles, both optimized for low drag at
\low speed in ways that still work well. The rolling resistance of
\narrow, large diameter tires is very low.
\
\Honda failed to sell many Civic FEs in the early 80's. Those were
\rated at up to 70 MPG and people actually got mid 50's from them. I
\had a 1978 Accord with their version of lean burn that delivered 36 -
\38 consistently and up to 44 on a trip. It was about the same size
\inside as a Saab or BMW, but not very powerful. Customers wanted more
\power instead and for 1980 Honda raised the HP and lowered the MPG. I
\still have one of those on jackstands in the garage.
\
\In 1991 I bought a 4WD, long bed Ranger with the 4 cylinder engine.
\Despite its 26-28 MPG the lower power made it undesirable and it sat
\on the lot until the end-of-year clearance. It's powerful enough for
\me up to about 60 MPH, top end is ~75. Ford soon discontinued that
\combination. I'm told the sixes can barely hit 20 MPG.
\
\We could have anything we wanted from a Segway on up, customer demand
\drives the market. The desire for safety regardless of low skills ansd
\inattention is a large part of it, otherwise just buy a midsized
\motorcycle.
\
\jsw
\running an alternate energy test with this laptop right now.
\

Do you think it would be difficult to get better than 20mpg from a Ford
Ranger (or other small truck) with descent performance? *Would it be best to
use something like a brushless servo motor or an AC motor with a VFD and
enough batteries in series to get the desired DC bus voltage? *I'm not sure
why a Ford Mustang claims 31mpg with a 6 cyl but a Ranger gets ~20mpg
either.

RogerN

I am a lab technician and don't specify the motors, controls or
batteries, just wire them all together. I know what works but not
always why it was the best choice.

Use the most efficient motor drive you are capable of designing or at
least understanding. Three phase AC motors with feedback seem to be a
common choice. The high-end stuff has very sophisticated redundant
computer controls, much of it for safety monitoring to hopefully avoid
Toyota incidents. How good are you with DSPs?

I think the 2.3l 4 has decent performance around town and in commuter
traffic. The truck has a 4.10 differential and enough zip to spin the
wheels coming off a light if the road is damp. Only 5th gear seems
sluggish. You can't go any faster than the car in front of you and
around here there is almost no place to pass. When it's full of logs
or old iron I drive slowly anyway and pull over a lot.

jsw