Tom:
I had posted an article about a new tranny that was in reality a manualk
transmission that shifted automatically:
Is this what you had in mind?
Richard in San Antonio
While the Chrysler Group may use some MB transmissions
for a few specialized applications, I expect that the bulk of
future Chrysler, Dodge and Jeep vehicles will continue to use
US built units. In-fact, I recently came across the patents for
an amazing new electro-mechanical automatic transmission
Chrysler is developing.
The goal of this new transmission is to combine the ease of
operation of an automatic with the superior fuel efficiency of
a manual. Automatic transmissions are less fuel efficient
automatic transmission for one primary reason: "In most
automatics the output of the engine connects to the input of
the transmission through a torque converter. Most torque
converters have an input turbine that is connected to the
output shaft of the engine and an input impeller that is
connected to the input shaft of the transmission."
" Movement of the turbine at the input side results in a
hydraulic fluid flow which causes a corresponding movement
of the hydraulic impeller connected to the input shaft of the
transmission.While torque converters provide a smooth
coupling between the engine and the transmission, the
slippage of the torque converter results in a parasitic loss,
thereby decreasing the efficiency of the powertrain."
"Before a shift between the gear ratios of a manual
transmission can occur, it is necessary to synchronize the
rotational speed of the driveshaft with the rotational speed
of the driven shaft. Typically, synchronization is obtained in
a manual transmission by way of a synchronizing
mechanism such as a mechanical synchronizer.. The
mechanical synchro varies the speed of the driveshaft to
match the speed of the driven shaft to enable smooth
engagement of the selected gear set."
The new transmission uses the basic design of a manual
transmission to eliminate the parasitic losses associated with
the torque converter on aconventional automatic. Dodge's
new transmission is "essentially an automated manual
transmission."
The design uses a dual clutch/dual input shaft layout, which
is the equivalent of having two transmissions in one housing.
Each transmission can be shifted and clutched independently
allowing for uninterrupted power when upshifting and
downshifting between gears. Besides dramaticaly improving
shifting, the system also yields significant increases in fuel
economy and performance.
Another cool feature is an integrated hill holder mechanism
which is an "engagable overrunning one-way roller clutch.
This clutch will be engaged when the transmission is in first,
second, or third gears in order to prevent vehicle rollback on
a hill. The hill holder prevents rollback of the vehicle when it
is stopped. Contrary to an automatic transmission, there is
no engine torque required to hold the vehicle from rolling
back on a grade, thus efficiency is improved."
Amazing stuff, proof once again that the engineers at the
Chrysler Group are always pushing the edge of the envelope.
Look for the innovative new six-speed transmission to show
up in the next generation Ram when it debuts in 2002.
Another interesting tidbit from the patent office is a recently
issued design patent for a tailgate. It's probably for the next
generation Ram, or perhaps the next generation Dakota? I
thought it'd be the perfect end for this column. Have a great
weekend.
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