20-04-2012, 11:22 AM
MICRO-CONTROLLER BASED AUTOMATIC ELECTRO-MAGNETIC GEAR SHIFTING SYSTEM
50452897-automatic-electro-magnetic-gear-shifting.pdf (Size: 2.74 MB / Downloads: 75)
INTRODUCTION
An automatic transmission allows a vehicle to change gear ratios from
a gearbox without requiring its driver to use a shift lever or a clutch.
Its origins date to 1894, when the modern automatic transmission was
introduced by Frenchmen Louis-Rene Panhard and Emile Levassor.
Ten years later, the concept was improved by the Sturtevant brothers
in Boston, Massachusetts.
The Sturtevant brothers developed the two-forward-speed automatic
transmission, but metal technology at the time was primitive and the
gearbox was prone to failure due to the stress of changing gear ratios.
Inventor Sturtevant designed the 1904 Automatic Tourer that featured
an internal combustion engine, a 3-speed semi-automatic gearbox,
automatic lubrication and vacuum brakes.
The Sturtevant automatic transmission serves as the blueprint for all
automatic cars and trucks on today's roads. The clutch-less automatic
car utilizes a gearbox that automatically changes the gear ratio, which
allows the driver to simply select one gear to move or park the
vehicle.
Automaker Reo developed the Self-Shifter in 1934 that basically used
two transmissions: one used at ordinary speeds and the second when
low gear was required to slow the vehicle.
In 1940, General Motors' Oldsmobile marketed a reliable version, the
Hydra-Matic, which combined a fluid coupling with three planetary
gearsets that were hydraulically controlled.
The Hydra-Matic was soon offered in Cadillacs and Pontiacs, but
World War II interrupted mass production for all civilian models and
was converted to military uses.
Buick followed with its Dynaflow in 1948; Packard offered the
Ultramatic in 1949; and Chevrolet debuted the Powerglide in 1950.
German and Japanese automakers are leading the way today with new
automatic technology, with BMW developing the first six-speed
automatic in 2002; Mercedes-Benz a seven-speed 7G-Tronic in 2003;
and Toyota's eight-speed found in the 2007 Lexus LS 460.
WORKING PRINCIPLE
A method of controlling a gear change of an automobile, said
automobile comprising an internal combustion engine.
An automatic transmission connected to an output rotation shaft of
said engine so as to transmit the rotational output of said engine to
drive wheels of said automobile through any selected one of a
plurality of gear ratios.
A load device selectively connectable to said output rotation shaft of
said engine via selectively-connecting means for generating a gear
change control signal for selecting one of said gear ratios of said
automatic transmission in accordance with one of operational
conditions of said automobile and said engine said method comprising
the steps of controlling said selectively-connecting means when said
gear change signal-generating means generates the control signal for
shifting up the gear in said automatic transmission, in such a manner
that said selectively-connecting means connects said load device to
said output rotation shaft of said engine.