The question was raised: do you keep the clutch or go clutchless with a conversion...
from
http://autos.groups.yahoo.com/group/.../message/56802
(the link partway down this text has some good pics of an adapter using the original clutch as an interface - but not for its traditional role - between the electric motor and transmission input shaft.)
CLUTCH VS CLUTCHLESS
Electric Vehicles of America, Inc. (EVA) provides both clutch and
clutchless designs. There are advantages and disadvantages to
both. The decision is the customers based on cost, vehicle make,
personal preference, etc.
EVA has used a clutchless design since 1987 and it works
successfully. However, because of some confusion, it should be
called a "clutch pedal-less design". We eliminate the clutch pedal
but not the clutch disk. The clutchless design is a direct
connection between the motor and the transmission. We mount your
clutch disk on a stainless steel and aluminum coupling; therefore it
matches the input shaft of your transmission and the springs in the
clutch disk absorb the initial shock from the motor.
In an internal combustion, not only is the engine always running,
but you have a massive flywheel. So there is lots of inertia and a
clutch is required. This is not so with an electric motor. The
motor stops when you stop. There is no idling. There also is
minimal inertia. Synchromesh transmissions easily handle any gear
change.
The clutch disk (provided by the customer) is critical. And we use
the existing clutch disk to connect the motor output shaft to the
input shaft of the transmission. The advantages of the clutch
pedal-less design are:
1. It allows the conversion of vehicles for which a clutch design
is not available or affordable. A manual transmission is
recommended because it allows you to operate the motor at higher
rpms but you do not have to add a clutch pedal assembly. This makes
it easier to convert vehicles that have an automatic transmission to
a manual transmission.
2. It eliminates the potential of overspeeding the motor with
different EV Users. If new drivers step on the accelerator and rev
the motor before popping the clutch, there is the possibility of
overspeeding the motor. This is a concern here in New England
because of the hills. With the clutch pedal-less design, you simply
put the transmission in gear and step on the accelerator. This
helps many high school drivers who may not have experience with
driving with a clutch.
3. The design is fairly simple. We need only three dimensions and
the clutch disk and we can make the adapter plate and coupling.
4. It allows the conversion of vehicles that once were automatics
without having to install the hydraulics etc. We have converted
existing S10s for the U.S. Air Force; they were automatics. We
just replaced the automatic transmission with a manual transmission
and used our design We did not have to install a clutch pedal and
all of the other hydraulics. this allows greater flexibility when
looking for a potential EV. The manual transmission is only $150.-
$300
5. Shifting is accomplished because of the minimal inertia of the
motor (no flywheel) and the synchromesh.
6. You save weight and money. One racing customer recently stated
that for every 7 lbs in rotational weight is equivalent to 100 lbs
of vehicle weight So by eliminating the flywheel and pressure
plate (35 lbs); it could be the equivalent to removing 500 lbs of
vehicle weight. The same goes with aluminum wheels vs steel wheels.
The disadvantage of the clutch pedal-less design are:
1. It takes a little longer (1-2 seconds) to shift. You cannot
speed shift. However, as I stated in my Driver Ed message, an EV
may drive in 2nd gear in town and 3rd gear on the highway. An S10
can be driven in 2nd gear from 0 -45 mph. So you don't need to
shift very often. With your car standing still and engine off.
Shift gears without pressing the clutch pedal. Notice how you can
go from one gear to the next without using the clutch. Why?
Because there is no inertia. It is the same way with the electric
motor, there is no huge mass of inertia. That is how the clutchless
design works.
2. Downshifting takes 1-2 seconds longer because the speeds have to
match. I usually downshift only at a stop sign coming off a
highway. Remember you shift an EV very infrequently. Usually only
2nd and 3rd gear are used.
We have customers who have the clutch pedal-less design (one with
more than 50,000 miles) and are happy and customers who would like
to try a clutch in their next EV because of their specific driving
conditions or habits (they always had one).
The synchros in the transmission make it smooth. Some people have
suggested that the synchros wear out quickly, but some of our
clutchless customers have more than 30,000 miles total on their
vehicles. For more information on clutchless, refer to Svein
Medhus' Ford Express Electric Home Page This is our customer in
Norway. This includes pictures of the installation of clutchless,
the clutch installation is similar. Another site is
http://www.geocities.com/CapeCanaveral/Lab/4429/cl3.htm
Once we asked someone on the West Coast why they thought a clutch
was required and how that myth got started. He stated that a clutch
was required on the old voltage switching and resistance controllers
in order to allow one to park without banging the others cars. This
problem was solved with PWM controllers.
As always, we just want to give the facts. We offer both. My
personal preference is the clutchless because of the convenience.
Our S-15 truck has a clutchless design and aluminum wheels - it gets
great range because we eliminated about 70 lbs in rotational weight.
Using the rule of thumb above - this represents about 1000 lbs of
vehicle weight. WOW!
The decision is made by the customer based on the specific vehicle,
cost, driving habits and experience.