10-06-2017, 06:51 AM
[attachment=14232]
ABSTRACT
In automobiles, the engine is a variable drive which transmits power. So gear box is
necessary to get required speed and torque. So the main concept of manual gear shift is to shift
the gear at a specific rpm in order to get maximum speed and torque.
A manual transmission, also known as a manual gearbox or standard transmission is a
type of transmission used in motor vehicle applications. It generally uses a driver-operated
clutch, typically operated by a pedal or lever, for regulating torque transfer from the internal
combustion engine to the transmission, and a gear-shift, either operated by hand (as in a car) or
by foot (as on a motorcycle). Other types of transmission in mainstream automotive use are the
automatic transmission, semi-automatic transmission, and the continuously variable transmission
(CVT).
A four-speed transmission is a transmission that allows a vehicle to operate at four
different speeds. This was an improvement on earlier transmissions, because it enabled the
vehicles that used the four-speed transmissions to run faster and better than the earlier
transmission systems. Most automobile vehicles today use the four-speed transmission.
1. INTRODUCTION
Manual transmissions are characterized by gear ratios that are selectable by locking
selected gear pairs to the output shaft inside the transmission. Conversely, most automatic
transmissions feature epicyclic (planetary) gearing controlled by brake bands and/or clutch packs
to select gear ratio. Contemporary automobile manual transmissions typically use four to six
forward gears and one reverse gear, although automobile manual transmissions have been built
with as few as two and as many as eight gears. Transmission for heavy trucks and other heavy
equipment usually have at least 9 gears so the transmission can offer both a wide range of gears
and close gear ratios to keep the engine running in the power band.
Manual gear shifting or manual transmissions come in two basic types: simple
unsynchronized systems where gears are spinning freely. Whereas the other one is the
synchronized systems, in which all gears are always in mesh but only one of these meshed pairs
of gears is locked to the shaft on which it is mounted at any one time, the others being allowed to
rotate freely; thus greatly reducing the skill required to shift gears.
1.1 Unsynchronized transmission
The earliest automotive transmissions were entirely mechanical unsynchronized gearing
systems. They could be shifted, with multiple gear ratios available to the operator, and even had
reverse. But the gears were engaged by sliding mechanisms or simple clutches, which required a
skilled operator who could use timing and careful throttle manipulation when shifting, so that the
gears would be spinning at roughly the same speed when engaged; otherwise the teeth would
refuse to mesh.
When upshifting to a higher gear, the speed of the gear driven by the engine had to drop
to match the speed of the next gear; as this happened naturally when the clutch was depressed, it
was just a matter of skill and experience to hear and feel when the gears could be persuaded to
mesh. However, when downshifting, the gear driven by the engine had to be sped up to mesh
with the output gear, requiring that the clutch be engaged so that the engine could be used to
speed up the gears; a technique called double declutching was used, which involved shifting the
transmission into neutral and speeding up the gears
ABSTRACT
In automobiles, the engine is a variable drive which transmits power. So gear box is
necessary to get required speed and torque. So the main concept of manual gear shift is to shift
the gear at a specific rpm in order to get maximum speed and torque.
A manual transmission, also known as a manual gearbox or standard transmission is a
type of transmission used in motor vehicle applications. It generally uses a driver-operated
clutch, typically operated by a pedal or lever, for regulating torque transfer from the internal
combustion engine to the transmission, and a gear-shift, either operated by hand (as in a car) or
by foot (as on a motorcycle). Other types of transmission in mainstream automotive use are the
automatic transmission, semi-automatic transmission, and the continuously variable transmission
(CVT).
A four-speed transmission is a transmission that allows a vehicle to operate at four
different speeds. This was an improvement on earlier transmissions, because it enabled the
vehicles that used the four-speed transmissions to run faster and better than the earlier
transmission systems. Most automobile vehicles today use the four-speed transmission.
1. INTRODUCTION
Manual transmissions are characterized by gear ratios that are selectable by locking
selected gear pairs to the output shaft inside the transmission. Conversely, most automatic
transmissions feature epicyclic (planetary) gearing controlled by brake bands and/or clutch packs
to select gear ratio. Contemporary automobile manual transmissions typically use four to six
forward gears and one reverse gear, although automobile manual transmissions have been built
with as few as two and as many as eight gears. Transmission for heavy trucks and other heavy
equipment usually have at least 9 gears so the transmission can offer both a wide range of gears
and close gear ratios to keep the engine running in the power band.
Manual gear shifting or manual transmissions come in two basic types: simple
unsynchronized systems where gears are spinning freely. Whereas the other one is the
synchronized systems, in which all gears are always in mesh but only one of these meshed pairs
of gears is locked to the shaft on which it is mounted at any one time, the others being allowed to
rotate freely; thus greatly reducing the skill required to shift gears.
1.1 Unsynchronized transmission
The earliest automotive transmissions were entirely mechanical unsynchronized gearing
systems. They could be shifted, with multiple gear ratios available to the operator, and even had
reverse. But the gears were engaged by sliding mechanisms or simple clutches, which required a
skilled operator who could use timing and careful throttle manipulation when shifting, so that the
gears would be spinning at roughly the same speed when engaged; otherwise the teeth would
refuse to mesh.
When upshifting to a higher gear, the speed of the gear driven by the engine had to drop
to match the speed of the next gear; as this happened naturally when the clutch was depressed, it
was just a matter of skill and experience to hear and feel when the gears could be persuaded to
mesh. However, when downshifting, the gear driven by the engine had to be sped up to mesh
with the output gear, requiring that the clutch be engaged so that the engine could be used to
speed up the gears; a technique called double declutching was used, which involved shifting the
transmission into neutral and speeding up the gears