WELCOME

AUTOMATIC GEAR SHIFTING IN TWO WHEELERSZIYAD.A12402063U7Guided by,SRI. U.PRAKASH(ASSOCIATE PROFESSOR MECHANICAL DEPARTMENT)105/08/2015

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INTRODUCTIONAUTOMATIC TRANSMISSIONVehicle can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually and to achieve efficient driving. ADVANTAGE: Easier to drive in stop and go traffic easier to use fuel efficient.

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Discussing two type automatic transmission in two wheelers:

Both gear and the clutch are controlled electro-mechanical by a microcontroller based computer system

continuously variable transmission.305/08/2015

Automatic gear shifting with microcontroller:

This system does not require any modification to the engine .

The equipment is mounted externally on the body of the motorcycle.

The system shifts the gear up and down electro magnetically , pneumatically , hydraulically like a human rider by sensing the speed of the vehicle.

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System shifts gear at exactly the correct speed , which produce smooth gear changing sequence.

Engine runs smoothly without knocking , which increases the engine life.

This system is different from the traditional automatic transmission used in cars.

Because , it uses electromechanical , pneumatic , hydraulic devices , which act similar to the human foot pressing gear pedal up and down and pressing the clutch lever like a human hand.

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Automatic gear shifting can be divided into three basis on the mechanism of actuators usedElectro mechanical

Pneumatic

Hydraulic605/08/2015

Electro-mechanical automatic gear shifting:- Main components :

Wheel speed sensor

Microcontroller

Electro-mechanical actuator

Relays 705/08/2015

Wheel speed sensor Working principle:It is a proximity sensor.Installed above the ring wheel.Ring wheel connected to the wheel hub/drive shaft.Speed sensor consists of permanent magnet .Magnetic field extend to the pulse wheel.Rotational movement of the pulse wheel and associated alteration of the teeth and gap changes the magnetic field.Induces an alternating voltage in the coil related to speed.Electronic in the sensor convert the resulting sinusoidal signal in to a digital signal.Transmitted to the microcontroller unit . 805/08/2015

Wheel speed sensor

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Microcontroller 2 microcontroller units(MCU) are used.MCU1- Function as to shift gear up and gear downControl the power of the ignition coilSensing the neutral position of the gearProducing the clutch enable signal to 2nd microcontroller

MCU2- Function as to control the clutch system by receiving signal from the gear system microcontrollerSensing the brake enable and disable condition for clutch pressing

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Brief working of microcontrollerWhen power is supplied to the system:-

MCU1 first sends signal to the gear shifting system to bring the gears into NEUTRAL position

MCU1 then sends signal to the gear shifting system to gear up when active signal is received.

MCU1 sends signal to the MCU2 to release half clutch when motorcycle running below 10 km/h

MCU1 gear down when speed sensor gives low active signal to gear down.

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RELAY Arelay is anelectrically operatedswitch

A switch is used to drive the microcontroller

Relays are used where it is necessary to control a circuit by a low-power signal.

Relay is used to sense the neutral gear position

In neutral position the relay provide an active low signal to the microcontroller

In any gear relay provide an active high signal to the microcontroller1205/08/2015

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Relay continued..Brake sensing relay is also used

To sense the brake activation and deactivation

Brake activation produce Active high signal

Brake deactivation produce active low signal

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Dc motor with lead screw actuatorsGenerally use high power DC motorThe output is given to lead screw will give linear motionTwo high power relays are used:For forward movement of the lead screw.For backward movement of the lead screw.

This lead screw is connected to a mechanical linkage Which will facilitate the forward and backward movement of the gear pedalThis same system can be install on the clutch system1405/08/2015

Gear shifting system attached to the motorcycle1505/08/2015

Clutch controlling system installed on the motorcycle

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Future developmentThe system is easily implement on other vehicle such as cars buses and trucksA few modifications need to made in the software and electro-mechanical system compatible with those vehicle to make .1705/08/2015

CONTINOUSLY VARIABLE TRANSMISSION:-CVT is an advanced technology of automatic transmission.

Unlike traditional automatic transmissions, continuously variable transmissions don't have a gearbox with a set number of gears.

CVT also known assingle-speed transmission,gearless transmission,one-speed automatic,variable pulley transmission.

Varies the transmission ratio continuously.

Shifts automatically with an infinite number of ratios.

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PULLEY BASED CVTIt consist of main 3 parts

1.Driver pulley 2.Driven pulley 3.Belt

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PULLEY BASED CVTLow gear

Top gear

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ADVANTAGESAllow for an infinite number of gear ratios.

Eliminates "shift shock" -- makes it smoother ride

Responds better to changing conditions.

Better fuel economy & power loss than automatic transmission

The main advantage of CVTs is that they allow an engine to run at its ideal RPM regardless of the speed of the vehicle.

There are fewer moving parts to a CVT transmission.2205/08/2015

DISADVANTAGESLimited torque capacity as compared to the manual transmission system

More costlier than manual transmission

Slipping in the drive belt or pulleys.

Additional gear train required for reverse condition.

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APPLICATIONSCommonly used in automobiles

New continuous variable transmission for medium duty trucks and buses.

Starts development on wind turbine CVT

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COMPARISONAUTOMATIC GEAR SHIFTING IN MOTORCYCLENo need of any modification to the engine .Equipment is externally installed No limited torque capacityFinite number of gear ratioGood economy can be obtainedCVT IN SCOOTERSNumber of gear sets are absent.Gear box itself changedHave limited torque capacityInfinite number of gear ratioLess economy

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CONCLUSIONThe applications and benefits of automatic transmissions in 2 wheeler can only increase based on todays research and development.2605/08/2015

REFERENCES Journal by Kevin R . Lang on (May 21, 2000) On Continuously Variable Transmissionshttps://books.google.co.in/books?id=bF3L7g1u_mQC&pg=PA3&lpg=PA3&dq=electronic+automatic+gear+shifting+system+for+a+motorcycle&source=bl&ots=zf5aCczrJi&sig=3KVBEJB8T_095tY7k_i0nE3S1Ro&hl=en&sa=X&ved=0CCUQ6AEwAWoVChMI2fmhoOuBxwIVx5uUCh2lqwS8#v=onepage&q=electronic%20automatic%20gear%20shifting%20system%20for%20a%20motorcycle&f=falseFritz Schmeier, Klaus Dietmayer , Rotational Speed Sensors KMI15/16 M. Anand Partheeban , DESIGN AND FABRICATION OF CONTINUOUS VARIABLE TRANSMISSION IN FOUR WHEELERS , IJAET2705/08/2015

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