Transmission System in Automotive Engineering
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Questions and Answers

What was the main purpose of developing independent front suspension in the 1930s?

  • To enhance vehicle appearance
  • To improve vehicle ride control and riding comfort (correct)
  • To improve vehicle speed
  • To reduce vehicle weight

    • What type of spring is commonly used in independent front suspension?

  • Leaf spring
  • Coil spring (correct)
  • Torsion bar
  • All of the above

    • What is the advantage of independent front suspension in terms of wheel movement?

  • Wheel movement is decreased
  • A greater wheel movement is utilized without affecting the steering system (correct)
  • Wheel movement is not affected
  • Less wheel movement is utilized

    • What is the effect of independent front suspension on wheel wobble?

    <p>It completely prevents wheel wobble</p> Signup and view all the answers

    What is the advantage of independent front suspension in terms of steering conditions?

    <p>Steering conditions are improved</p> Signup and view all the answers

    Which of the following is NOT a type of independent front suspension?

    <p>Rigid axle front suspension</p> Signup and view all the answers

    Which type of suspension is used in all vehicles nowadays?

    <p>Independent front suspension</p> Signup and view all the answers

    What is the effect of independent front suspension on the front wheels?

    <p>Each front wheel is mounted on its own axle</p> Signup and view all the answers

    What is the advantage of independent front suspension in terms of road conditions?

    <p>The wheels respond individually to road conditions</p> Signup and view all the answers

    How many types of independent front suspension are mentioned in the content?

    <p>6</p> Signup and view all the answers

    What is the primary benefit of using independent front suspension in vehicles?

    <p>Improved vehicle ride control and riding comfort</p> Signup and view all the answers

    Which type of spring is used in longitudinal suspension?

    <p>Coil spring</p> Signup and view all the answers

    What is the effect of a wider spacing of the front springs on steering conditions?

    <p>Improved steering quality</p> Signup and view all the answers

    How do the front wheels respond to road conditions in an independent front suspension system?

    <p>Individually, each responding to its own road conditions</p> Signup and view all the answers

    What is the function of a coil or torsion bar or leaf spring in an independent front suspension system?

    <p>To support the front wheels independently</p> Signup and view all the answers

    Which type of independent front suspension system is characterized by a sliding motion?

    <p>Sliding suspension</p> Signup and view all the answers

    What is the primary difference between a longitudinal suspension and a transverse suspension?

    <p>The orientation of the suspension</p> Signup and view all the answers

    Which of the following is a type of independent front suspension system?

    <p>Mac Pherson Strut and link type suspension</p> Signup and view all the answers

    What is the primary advantage of using a Mac Pherson Strut and link type suspension?

    <p>Improved ride control and riding comfort</p> Signup and view all the answers

    Which type of suspension system is commonly used in modern vehicles?

    <p>Independent front suspension</p> Signup and view all the answers

    What is the primary benefit of using independent front suspension in vehicles?

    <p>Enhanced vehicle ride control and riding comfort</p> Signup and view all the answers

    What is the characteristic of independent front suspension system?

    <p>Each front wheel is mounted on its own axle and independently supported</p> Signup and view all the answers

    What is the effect of independent front suspension on vehicle steering?

    <p>It improves the steering quality</p> Signup and view all the answers

    Which type of suspension system is used in modern vehicles?

    <p>Independent front suspension</p> Signup and view all the answers

    What is the function of coil or torsion bar or leaf spring in independent front suspension?

    <p>To support the front wheels independently</p> Signup and view all the answers

    What is the advantage of independent front suspension in terms of wheel movement?

    <p>It allows for a greater wheel movement</p> Signup and view all the answers

    How do the front wheels respond to road conditions in an independent front suspension system?

    <p>Independently, as separate units</p> Signup and view all the answers

    What is the characteristic of longitudinal leaf spring rear suspension?

    <p>The leaf spring is mounted longitudinally</p> Signup and view all the answers

    How many types of independent front suspensions are mentioned in the content?

    <p>7</p> Signup and view all the answers

    What is the primary advantage of using a coil spring in independent front suspension?

    <p>It improves the vehicle ride control and riding comfort</p> Signup and view all the answers

    What is the primary benefit of independent front suspension in terms of vehicle performance?

    <p>Improved ride control and riding comfort</p> Signup and view all the answers

    Which of the following is a characteristic of independent front suspension?

    <p>Each front wheel is mounted on its own axle</p> Signup and view all the answers

    What is the purpose of a coil or torsion bar or leaf spring in independent front suspension?

    <p>To absorb shocks and support the wheel</p> Signup and view all the answers

    Which of the following types of independent front suspension uses a sliding motion?

    <p>Sliding suspension</p> Signup and view all the answers

    What is the effect of a wider spacing of the front springs on the steering system?

    <p>It improves the steering system</p> Signup and view all the answers

    Which type of independent front suspension uses a combination of a coil spring and a link?

    <p>Mac Pherson Strut and link type suspension</p> Signup and view all the answers

    What is the primary difference between longitudinal and transverse suspensions?

    <p>Direction of the suspension</p> Signup and view all the answers

    Which type of suspension is most commonly used in modern vehicles?

    <p>Independent front suspension</p> Signup and view all the answers

    What is the effect of independent front suspension on the vehicle's response to road conditions?

    <p>The wheels respond individually to road conditions</p> Signup and view all the answers

    What is the characteristic of independent front suspension that improves vehicle stability?

    <p>Each front wheel is mounted on its own axle</p> Signup and view all the answers

    Study Notes

    Transmission System

    • The transmission system plays a crucial role in transferring power from the engine to the wheels, enabling the vehicle to move efficiently across different speeds and conditions.
    • Components of a transmission system:
      • Transmission (manual or automatic)
      • Clutch (for manual transmission)
      • Gearbox
      • Differential
      • Driveshaft (propeller shaft)
      • Torque converter (for automatic transmission)

    Functions of a Transmission System

    • Gear ratio selection
    • Torque multiplication
    • Smooth power delivery
    • Adaptability to driving conditions
    • Efficiency improvement (modern transmission systems aim to optimize fuel efficiency and reduce emissions)

    Clutches and Power Transmission

    • The purpose of the clutch is to allow the driver to couple or decouple the engine and transmission.
    • Requirements of a clutch:
      • Pick up its load smoothly without grab or clatter
      • Have a driven disc of low moment of inertia to permit easy shifting
      • Damp out any vibration of the crankshaft to prevent gear clatter
      • Require little pedal pressure to operate
      • Be easy to adjust and service
      • Be cheap to manufacture

    Types of Clutches

    • Positive clutches
      • Merits: simple, no slip, no heat generated, compact, and low cost
    • Friction clutches
      • Merits: smooth engagement, can slip during engagement, high torque capacity
      • Types:
        • Single plate clutch
        • Multi-plate clutch
        • Centrifugal clutch
        • Semi-centrifugal clutch
        • Diaphragm spring single plate clutch
        • Electro-magnetic clutch
        • Overrunning clutch or free-wheel unit

    Diaphragm Spring Single Plate Clutch

    • Advantages:
      • Compact design
      • Easier to balance rotationally
      • Uniformly distributed pressure on pressure plate
      • No release levers required
      • Minimum effort required to disengage the clutch
      • Minimum internal friction

    Multi-Plate Clutch

    • Used in heavy transport vehicles, epicyclic gearboxes, and racing cars
    • Advantages:
      • Higher torque transmission capacity
      • Compact design

    Automatic Clutch

    • Centrifugal clutch: automatically disengages when speed falls below a certain value and re-engages when speed rises above it
    • Fluid coupling or fluid torque converter: used to transmit power between two rotating shafts without Interrupting the flow of power

    Gear Box in an Automobile

    • Necessity of gear box: to maintain engine speed at the most economical value under all conditions of vehicle movement
    • Functions of a gear box:
      • Torque ratio variation between engine and wheels
      • Means of reversal of vehicle motion
      • Transmission can be disconnected from engine by neutral position of gear box

    Types of Gear Box

    • Progressive type gear box
    • Epicyclic (or) planetary type gear box
    • Selective type gear box (e.g., constant mesh gear box with positive dog clutch, constant mesh gear box with synchromesh device, sliding mesh gear box)### Gearbox
    • A gearbox is a mechanical device that uses gears to transmit and change the speed of rotation of a mechanical shaft
    • Types of gearboxes:
      • Constant mesh gearbox
      • Synchromesh gearbox
      • Automatic gearbox

    Constant Mesh Gearbox

    • All gears on the main shaft are in constant mesh with the corresponding gears on the lay shaft
    • Gears on the lay shaft are fixed, while those on the main shaft are free to rotate
    • Dog clutches are used to engage and disengage gears

    Synchromesh Gearbox

    • Similar to constant mesh gearbox, but with synchronizers instead of dog clutches
    • Synchronizers allow for smooth gear changes by equalizing the speed of the gears before engagement
    • Used in modern cars to reduce the cost of production

    Automatic Gearbox

    • Also known as automatic transmission
    • Uses a complex system of gears, clutches, and hydraulic pumps to change gear ratios automatically
    • Components:
      • Torque converter
      • Planetary gear sets
      • Hydraulic system
      • Control unit (TCU or TCM)
    • Working:
      • The TCU receives inputs from sensors and determines the appropriate gear ratio
      • Hydraulic pressure is used to engage and disengage clutches and brake bands
      • Shift points are determined by factors such as vehicle speed, engine load, and driver demand

    Differential

    • A mechanical device that allows each of the driving wheels to rotate at different speeds
    • Purpose:
      • To drive a pair of wheels with equal torque while allowing them to rotate at different speeds
      • To prevent wheel spinning and road damage when turning
    • Components:
      • Pinion drive gear
      • Crown wheel/ring gear
      • Spider/planet gear
      • Cross-pin
      • Side/sun gear
      • Differential case assembly
    • Construction:
      • The differential is an arrangement of gears that work together to allow the vehicle to take a turn smoothly
      • The pinion gear is fixed to the propeller shaft and rotates the crown wheel

    Suspension System

    • The chassis of the vehicle is connected to the front and rear wheels through the medium of springs, shock absorbers, and axles
    • Components:
      • Springs
      • Dampers (shock absorbers)
      • Stabilizer (sway bar or anti-roll bar)
      • Linkage system
    • Functions:
      • To eliminate road shocks from transmission to vehicle components
      • To obtain good road holding while driving, cornering, and braking
      • To keep the proper steering geometry
      • To obtain a particular height to body structure
      • To resist the torque and braking reactions
      • To maintain the stability of the vehicle while traveling over rough roads
      • To safeguard the occupants against road shocks and provide a riding comfort

    Sprung Weight and Unsprung Weight

    • Sprung weight: The weight of the vehicle body that is supported by springs
    • Unsprung weight: The weight of the wheels, axles, and other parts of the vehicle that are not supported by springs
    • Effects of unsprung weight:
      • Controls the trade-off between wheel bump and vibration isolation
      • Affects the ride quality and road noise
      • Exacerbates wheel control issues under hard acceleration or braking### Types of Springs
    • There are five types of springs: compression, compression-shear, steel reinforced, progressive, and face shear springs.
    • Air springs are also used in air suspension systems, which can be adjusted up or down by supplying air pressure.

    Leaf Spring Suspension

    • Leaf spring suspension consists of a number of leaves of increasing lengths made of steel plates.
    • The spring eye is mounted to the frame by a pin called shackle pin.
    • The centre portion of the spring is attached to the front axle by a V-bolt.
    • The stiffness or spring rate of the leaf spring is determined by its length, width, and thickness.
    • Greater the number of leaves, higher the stiffness.

    Air Suspension System

    • Air springs are flexible bellows made of textile-reinforced rubber, containing compressed air.
    • They are used to carry load on vehicles and provide elasticity or "springiness" when compressed.
    • Air springs have three characteristics: they are soft when unloaded, they increase stiffness when loaded, and they maintain constant vehicle height.
    • They provide optimum riding comfort in both lightly loaded and fully loaded conditions.

    Shock Absorber

    • Shock absorbers are used to control vibrations on springs, provide comfortable ride, and act flexible and rigid.
    • They are used as a part of the suspension system and provide more resistance to the motion of the spring and road wheel.
    • Types of shock absorbers include mechanical, hydraulic, and telescopic shock absorbers.

    Telescopic Shock Absorber

    • Construction consists of an upper eye attached to the axle, a lower eye attached to the chassis frame, and two-way valves.
    • Working involves fluid flowing between the valves to produce a damping force.
    • The damping force varies with the speed of the piston.

    Types of Suspension System

    • There are two basic types of suspension systems: front end suspension and rear end suspension.
    • Front end suspension types include independent front suspension and rigid axle front suspension.
    • Rear end suspension types include longitudinal leaf spring, transverse leaf spring, and coil spring rear end suspension.

    Independent Front Suspension

    • Developed in the 1930s to improve vehicle ride control and riding comfort.
    • Each front wheel is mounted on its own axle and independently supported by a coil or torsion bar or leaf spring.
    • Types of independent front suspensions include longitudinal, transverse, sliding, MacPherson Strut, parallelogram, trailing link, and vertical guide suspensions.

    Transmission System

    • The transmission system plays a crucial role in transferring power from the engine to the wheels, enabling the vehicle to move efficiently across different speeds and conditions.
    • Components of a transmission system:
      • Transmission (manual or automatic)
      • Clutch (for manual transmission)
      • Gearbox
      • Differential
      • Driveshaft (propeller shaft)
      • Torque converter (for automatic transmission)

    Functions of a Transmission System

    • Gear ratio selection
    • Torque multiplication
    • Smooth power delivery
    • Adaptability to driving conditions
    • Efficiency improvement (modern transmission systems aim to optimize fuel efficiency and reduce emissions)

    Clutches and Power Transmission

    • The purpose of the clutch is to allow the driver to couple or decouple the engine and transmission.
    • Requirements of a clutch:
      • Pick up its load smoothly without grab or clatter
      • Have a driven disc of low moment of inertia to permit easy shifting
      • Damp out any vibration of the crankshaft to prevent gear clatter
      • Require little pedal pressure to operate
      • Be easy to adjust and service
      • Be cheap to manufacture

    Types of Clutches

    • Positive clutches
      • Merits: simple, no slip, no heat generated, compact, and low cost
    • Friction clutches
      • Merits: smooth engagement, can slip during engagement, high torque capacity
      • Types:
        • Single plate clutch
        • Multi-plate clutch
        • Centrifugal clutch
        • Semi-centrifugal clutch
        • Diaphragm spring single plate clutch
        • Electro-magnetic clutch
        • Overrunning clutch or free-wheel unit

    Diaphragm Spring Single Plate Clutch

    • Advantages:
      • Compact design
      • Easier to balance rotationally
      • Uniformly distributed pressure on pressure plate
      • No release levers required
      • Minimum effort required to disengage the clutch
      • Minimum internal friction

    Multi-Plate Clutch

    • Used in heavy transport vehicles, epicyclic gearboxes, and racing cars
    • Advantages:
      • Higher torque transmission capacity
      • Compact design

    Automatic Clutch

    • Centrifugal clutch: automatically disengages when speed falls below a certain value and re-engages when speed rises above it
    • Fluid coupling or fluid torque converter: used to transmit power between two rotating shafts without Interrupting the flow of power

    Gear Box in an Automobile

    • Necessity of gear box: to maintain engine speed at the most economical value under all conditions of vehicle movement
    • Functions of a gear box:
      • Torque ratio variation between engine and wheels
      • Means of reversal of vehicle motion
      • Transmission can be disconnected from engine by neutral position of gear box

    Types of Gear Box

    • Progressive type gear box
    • Epicyclic (or) planetary type gear box
    • Selective type gear box (e.g., constant mesh gear box with positive dog clutch, constant mesh gear box with synchromesh device, sliding mesh gear box)### Gearbox
    • A gearbox is a mechanical device that uses gears to transmit and change the speed of rotation of a mechanical shaft
    • Types of gearboxes:
      • Constant mesh gearbox
      • Synchromesh gearbox
      • Automatic gearbox

    Constant Mesh Gearbox

    • All gears on the main shaft are in constant mesh with the corresponding gears on the lay shaft
    • Gears on the lay shaft are fixed, while those on the main shaft are free to rotate
    • Dog clutches are used to engage and disengage gears

    Synchromesh Gearbox

    • Similar to constant mesh gearbox, but with synchronizers instead of dog clutches
    • Synchronizers allow for smooth gear changes by equalizing the speed of the gears before engagement
    • Used in modern cars to reduce the cost of production

    Automatic Gearbox

    • Also known as automatic transmission
    • Uses a complex system of gears, clutches, and hydraulic pumps to change gear ratios automatically
    • Components:
      • Torque converter
      • Planetary gear sets
      • Hydraulic system
      • Control unit (TCU or TCM)
    • Working:
      • The TCU receives inputs from sensors and determines the appropriate gear ratio
      • Hydraulic pressure is used to engage and disengage clutches and brake bands
      • Shift points are determined by factors such as vehicle speed, engine load, and driver demand

    Differential

    • A mechanical device that allows each of the driving wheels to rotate at different speeds
    • Purpose:
      • To drive a pair of wheels with equal torque while allowing them to rotate at different speeds
      • To prevent wheel spinning and road damage when turning
    • Components:
      • Pinion drive gear
      • Crown wheel/ring gear
      • Spider/planet gear
      • Cross-pin
      • Side/sun gear
      • Differential case assembly
    • Construction:
      • The differential is an arrangement of gears that work together to allow the vehicle to take a turn smoothly
      • The pinion gear is fixed to the propeller shaft and rotates the crown wheel

    Suspension System

    • The chassis of the vehicle is connected to the front and rear wheels through the medium of springs, shock absorbers, and axles
    • Components:
      • Springs
      • Dampers (shock absorbers)
      • Stabilizer (sway bar or anti-roll bar)
      • Linkage system
    • Functions:
      • To eliminate road shocks from transmission to vehicle components
      • To obtain good road holding while driving, cornering, and braking
      • To keep the proper steering geometry
      • To obtain a particular height to body structure
      • To resist the torque and braking reactions
      • To maintain the stability of the vehicle while traveling over rough roads
      • To safeguard the occupants against road shocks and provide a riding comfort

    Sprung Weight and Unsprung Weight

    • Sprung weight: The weight of the vehicle body that is supported by springs
    • Unsprung weight: The weight of the wheels, axles, and other parts of the vehicle that are not supported by springs
    • Effects of unsprung weight:
      • Controls the trade-off between wheel bump and vibration isolation
      • Affects the ride quality and road noise
      • Exacerbates wheel control issues under hard acceleration or braking### Types of Springs
    • There are five types of springs: compression, compression-shear, steel reinforced, progressive, and face shear springs.
    • Air springs are also used in air suspension systems, which can be adjusted up or down by supplying air pressure.

    Leaf Spring Suspension

    • Leaf spring suspension consists of a number of leaves of increasing lengths made of steel plates.
    • The spring eye is mounted to the frame by a pin called shackle pin.
    • The centre portion of the spring is attached to the front axle by a V-bolt.
    • The stiffness or spring rate of the leaf spring is determined by its length, width, and thickness.
    • Greater the number of leaves, higher the stiffness.

    Air Suspension System

    • Air springs are flexible bellows made of textile-reinforced rubber, containing compressed air.
    • They are used to carry load on vehicles and provide elasticity or "springiness" when compressed.
    • Air springs have three characteristics: they are soft when unloaded, they increase stiffness when loaded, and they maintain constant vehicle height.
    • They provide optimum riding comfort in both lightly loaded and fully loaded conditions.

    Shock Absorber

    • Shock absorbers are used to control vibrations on springs, provide comfortable ride, and act flexible and rigid.
    • They are used as a part of the suspension system and provide more resistance to the motion of the spring and road wheel.
    • Types of shock absorbers include mechanical, hydraulic, and telescopic shock absorbers.

    Telescopic Shock Absorber

    • Construction consists of an upper eye attached to the axle, a lower eye attached to the chassis frame, and two-way valves.
    • Working involves fluid flowing between the valves to produce a damping force.
    • The damping force varies with the speed of the piston.

    Types of Suspension System

    • There are two basic types of suspension systems: front end suspension and rear end suspension.
    • Front end suspension types include independent front suspension and rigid axle front suspension.
    • Rear end suspension types include longitudinal leaf spring, transverse leaf spring, and coil spring rear end suspension.

    Independent Front Suspension

    • Developed in the 1930s to improve vehicle ride control and riding comfort.
    • Each front wheel is mounted on its own axle and independently supported by a coil or torsion bar or leaf spring.
    • Types of independent front suspensions include longitudinal, transverse, sliding, MacPherson Strut, parallelogram, trailing link, and vertical guide suspensions.

    Transmission System

    • The transmission system plays a crucial role in transferring power from the engine to the wheels, enabling the vehicle to move efficiently across different speeds and conditions.
    • Components of a transmission system:
      • Transmission (manual or automatic)
      • Clutch (for manual transmission)
      • Gearbox
      • Differential
      • Driveshaft (propeller shaft)
      • Torque converter (for automatic transmission)

    Functions of a Transmission System

    • Gear ratio selection
    • Torque multiplication
    • Smooth power delivery
    • Adaptability to driving conditions
    • Efficiency improvement (modern transmission systems aim to optimize fuel efficiency and reduce emissions)

    Clutches and Power Transmission

    • The purpose of the clutch is to allow the driver to couple or decouple the engine and transmission.
    • Requirements of a clutch:
      • Pick up its load smoothly without grab or clatter
      • Have a driven disc of low moment of inertia to permit easy shifting
      • Damp out any vibration of the crankshaft to prevent gear clatter
      • Require little pedal pressure to operate
      • Be easy to adjust and service
      • Be cheap to manufacture

    Types of Clutches

    • Positive clutches
      • Merits: simple, no slip, no heat generated, compact, and low cost
    • Friction clutches
      • Merits: smooth engagement, can slip during engagement, high torque capacity
      • Types:
        • Single plate clutch
        • Multi-plate clutch
        • Centrifugal clutch
        • Semi-centrifugal clutch
        • Diaphragm spring single plate clutch
        • Electro-magnetic clutch
        • Overrunning clutch or free-wheel unit

    Diaphragm Spring Single Plate Clutch

    • Advantages:
      • Compact design
      • Easier to balance rotationally
      • Uniformly distributed pressure on pressure plate
      • No release levers required
      • Minimum effort required to disengage the clutch
      • Minimum internal friction

    Multi-Plate Clutch

    • Used in heavy transport vehicles, epicyclic gearboxes, and racing cars
    • Advantages:
      • Higher torque transmission capacity
      • Compact design

    Automatic Clutch

    • Centrifugal clutch: automatically disengages when speed falls below a certain value and re-engages when speed rises above it
    • Fluid coupling or fluid torque converter: used to transmit power between two rotating shafts without Interrupting the flow of power

    Gear Box in an Automobile

    • Necessity of gear box: to maintain engine speed at the most economical value under all conditions of vehicle movement
    • Functions of a gear box:
      • Torque ratio variation between engine and wheels
      • Means of reversal of vehicle motion
      • Transmission can be disconnected from engine by neutral position of gear box

    Types of Gear Box

    • Progressive type gear box
    • Epicyclic (or) planetary type gear box
    • Selective type gear box (e.g., constant mesh gear box with positive dog clutch, constant mesh gear box with synchromesh device, sliding mesh gear box)### Gearbox
    • A gearbox is a mechanical device that uses gears to transmit and change the speed of rotation of a mechanical shaft
    • Types of gearboxes:
      • Constant mesh gearbox
      • Synchromesh gearbox
      • Automatic gearbox

    Constant Mesh Gearbox

    • All gears on the main shaft are in constant mesh with the corresponding gears on the lay shaft
    • Gears on the lay shaft are fixed, while those on the main shaft are free to rotate
    • Dog clutches are used to engage and disengage gears

    Synchromesh Gearbox

    • Similar to constant mesh gearbox, but with synchronizers instead of dog clutches
    • Synchronizers allow for smooth gear changes by equalizing the speed of the gears before engagement
    • Used in modern cars to reduce the cost of production

    Automatic Gearbox

    • Also known as automatic transmission
    • Uses a complex system of gears, clutches, and hydraulic pumps to change gear ratios automatically
    • Components:
      • Torque converter
      • Planetary gear sets
      • Hydraulic system
      • Control unit (TCU or TCM)
    • Working:
      • The TCU receives inputs from sensors and determines the appropriate gear ratio
      • Hydraulic pressure is used to engage and disengage clutches and brake bands
      • Shift points are determined by factors such as vehicle speed, engine load, and driver demand

    Differential

    • A mechanical device that allows each of the driving wheels to rotate at different speeds
    • Purpose:
      • To drive a pair of wheels with equal torque while allowing them to rotate at different speeds
      • To prevent wheel spinning and road damage when turning
    • Components:
      • Pinion drive gear
      • Crown wheel/ring gear
      • Spider/planet gear
      • Cross-pin
      • Side/sun gear
      • Differential case assembly
    • Construction:
      • The differential is an arrangement of gears that work together to allow the vehicle to take a turn smoothly
      • The pinion gear is fixed to the propeller shaft and rotates the crown wheel

    Suspension System

    • The chassis of the vehicle is connected to the front and rear wheels through the medium of springs, shock absorbers, and axles
    • Components:
      • Springs
      • Dampers (shock absorbers)
      • Stabilizer (sway bar or anti-roll bar)
      • Linkage system
    • Functions:
      • To eliminate road shocks from transmission to vehicle components
      • To obtain good road holding while driving, cornering, and braking
      • To keep the proper steering geometry
      • To obtain a particular height to body structure
      • To resist the torque and braking reactions
      • To maintain the stability of the vehicle while traveling over rough roads
      • To safeguard the occupants against road shocks and provide a riding comfort

    Sprung Weight and Unsprung Weight

    • Sprung weight: The weight of the vehicle body that is supported by springs
    • Unsprung weight: The weight of the wheels, axles, and other parts of the vehicle that are not supported by springs
    • Effects of unsprung weight:
      • Controls the trade-off between wheel bump and vibration isolation
      • Affects the ride quality and road noise
      • Exacerbates wheel control issues under hard acceleration or braking### Types of Springs
    • There are five types of springs: compression, compression-shear, steel reinforced, progressive, and face shear springs.
    • Air springs are also used in air suspension systems, which can be adjusted up or down by supplying air pressure.

    Leaf Spring Suspension

    • Leaf spring suspension consists of a number of leaves of increasing lengths made of steel plates.
    • The spring eye is mounted to the frame by a pin called shackle pin.
    • The centre portion of the spring is attached to the front axle by a V-bolt.
    • The stiffness or spring rate of the leaf spring is determined by its length, width, and thickness.
    • Greater the number of leaves, higher the stiffness.

    Air Suspension System

    • Air springs are flexible bellows made of textile-reinforced rubber, containing compressed air.
    • They are used to carry load on vehicles and provide elasticity or "springiness" when compressed.
    • Air springs have three characteristics: they are soft when unloaded, they increase stiffness when loaded, and they maintain constant vehicle height.
    • They provide optimum riding comfort in both lightly loaded and fully loaded conditions.

    Shock Absorber

    • Shock absorbers are used to control vibrations on springs, provide comfortable ride, and act flexible and rigid.
    • They are used as a part of the suspension system and provide more resistance to the motion of the spring and road wheel.
    • Types of shock absorbers include mechanical, hydraulic, and telescopic shock absorbers.

    Telescopic Shock Absorber

    • Construction consists of an upper eye attached to the axle, a lower eye attached to the chassis frame, and two-way valves.
    • Working involves fluid flowing between the valves to produce a damping force.
    • The damping force varies with the speed of the piston.

    Types of Suspension System

    • There are two basic types of suspension systems: front end suspension and rear end suspension.
    • Front end suspension types include independent front suspension and rigid axle front suspension.
    • Rear end suspension types include longitudinal leaf spring, transverse leaf spring, and coil spring rear end suspension.

    Independent Front Suspension

    • Developed in the 1930s to improve vehicle ride control and riding comfort.
    • Each front wheel is mounted on its own axle and independently supported by a coil or torsion bar or leaf spring.
    • Types of independent front suspensions include longitudinal, transverse, sliding, MacPherson Strut, parallelogram, trailing link, and vertical guide suspensions.

    Transmission System

    • The transmission system plays a crucial role in transferring power from the engine to the wheels, enabling the vehicle to move efficiently across different speeds and conditions.
    • Components of a transmission system:
      • Transmission (manual or automatic)
      • Clutch (for manual transmission)
      • Gearbox
      • Differential
      • Driveshaft (propeller shaft)
      • Torque converter (for automatic transmission)

    Functions of a Transmission System

    • Gear ratio selection
    • Torque multiplication
    • Smooth power delivery
    • Adaptability to driving conditions
    • Efficiency improvement (modern transmission systems aim to optimize fuel efficiency and reduce emissions)

    Clutches and Power Transmission

    • The purpose of the clutch is to allow the driver to couple or decouple the engine and transmission.
    • Requirements of a clutch:
      • Pick up its load smoothly without grab or clatter
      • Have a driven disc of low moment of inertia to permit easy shifting
      • Damp out any vibration of the crankshaft to prevent gear clatter
      • Require little pedal pressure to operate
      • Be easy to adjust and service
      • Be cheap to manufacture

    Types of Clutches

    • Positive clutches
      • Merits: simple, no slip, no heat generated, compact, and low cost
    • Friction clutches
      • Merits: smooth engagement, can slip during engagement, high torque capacity
      • Types:
        • Single plate clutch
        • Multi-plate clutch
        • Centrifugal clutch
        • Semi-centrifugal clutch
        • Diaphragm spring single plate clutch
        • Electro-magnetic clutch
        • Overrunning clutch or free-wheel unit

    Diaphragm Spring Single Plate Clutch

    • Advantages:
      • Compact design
      • Easier to balance rotationally
      • Uniformly distributed pressure on pressure plate
      • No release levers required
      • Minimum effort required to disengage the clutch
      • Minimum internal friction

    Multi-Plate Clutch

    • Used in heavy transport vehicles, epicyclic gearboxes, and racing cars
    • Advantages:
      • Higher torque transmission capacity
      • Compact design

    Automatic Clutch

    • Centrifugal clutch: automatically disengages when speed falls below a certain value and re-engages when speed rises above it
    • Fluid coupling or fluid torque converter: used to transmit power between two rotating shafts without Interrupting the flow of power

    Gear Box in an Automobile

    • Necessity of gear box: to maintain engine speed at the most economical value under all conditions of vehicle movement
    • Functions of a gear box:
      • Torque ratio variation between engine and wheels
      • Means of reversal of vehicle motion
      • Transmission can be disconnected from engine by neutral position of gear box

    Types of Gear Box

    • Progressive type gear box
    • Epicyclic (or) planetary type gear box
    • Selective type gear box (e.g., constant mesh gear box with positive dog clutch, constant mesh gear box with synchromesh device, sliding mesh gear box)### Gearbox
    • A gearbox is a mechanical device that uses gears to transmit and change the speed of rotation of a mechanical shaft
    • Types of gearboxes:
      • Constant mesh gearbox
      • Synchromesh gearbox
      • Automatic gearbox

    Constant Mesh Gearbox

    • All gears on the main shaft are in constant mesh with the corresponding gears on the lay shaft
    • Gears on the lay shaft are fixed, while those on the main shaft are free to rotate
    • Dog clutches are used to engage and disengage gears

    Synchromesh Gearbox

    • Similar to constant mesh gearbox, but with synchronizers instead of dog clutches
    • Synchronizers allow for smooth gear changes by equalizing the speed of the gears before engagement
    • Used in modern cars to reduce the cost of production

    Automatic Gearbox

    • Also known as automatic transmission
    • Uses a complex system of gears, clutches, and hydraulic pumps to change gear ratios automatically
    • Components:
      • Torque converter
      • Planetary gear sets
      • Hydraulic system
      • Control unit (TCU or TCM)
    • Working:
      • The TCU receives inputs from sensors and determines the appropriate gear ratio
      • Hydraulic pressure is used to engage and disengage clutches and brake bands
      • Shift points are determined by factors such as vehicle speed, engine load, and driver demand

    Differential

    • A mechanical device that allows each of the driving wheels to rotate at different speeds
    • Purpose:
      • To drive a pair of wheels with equal torque while allowing them to rotate at different speeds
      • To prevent wheel spinning and road damage when turning
    • Components:
      • Pinion drive gear
      • Crown wheel/ring gear
      • Spider/planet gear
      • Cross-pin
      • Side/sun gear
      • Differential case assembly
    • Construction:
      • The differential is an arrangement of gears that work together to allow the vehicle to take a turn smoothly
      • The pinion gear is fixed to the propeller shaft and rotates the crown wheel

    Suspension System

    • The chassis of the vehicle is connected to the front and rear wheels through the medium of springs, shock absorbers, and axles
    • Components:
      • Springs
      • Dampers (shock absorbers)
      • Stabilizer (sway bar or anti-roll bar)
      • Linkage system
    • Functions:
      • To eliminate road shocks from transmission to vehicle components
      • To obtain good road holding while driving, cornering, and braking
      • To keep the proper steering geometry
      • To obtain a particular height to body structure
      • To resist the torque and braking reactions
      • To maintain the stability of the vehicle while traveling over rough roads
      • To safeguard the occupants against road shocks and provide a riding comfort

    Sprung Weight and Unsprung Weight

    • Sprung weight: The weight of the vehicle body that is supported by springs
    • Unsprung weight: The weight of the wheels, axles, and other parts of the vehicle that are not supported by springs
    • Effects of unsprung weight:
      • Controls the trade-off between wheel bump and vibration isolation
      • Affects the ride quality and road noise
      • Exacerbates wheel control issues under hard acceleration or braking### Types of Springs
    • There are five types of springs: compression, compression-shear, steel reinforced, progressive, and face shear springs.
    • Air springs are also used in air suspension systems, which can be adjusted up or down by supplying air pressure.

    Leaf Spring Suspension

    • Leaf spring suspension consists of a number of leaves of increasing lengths made of steel plates.
    • The spring eye is mounted to the frame by a pin called shackle pin.
    • The centre portion of the spring is attached to the front axle by a V-bolt.
    • The stiffness or spring rate of the leaf spring is determined by its length, width, and thickness.
    • Greater the number of leaves, higher the stiffness.

    Air Suspension System

    • Air springs are flexible bellows made of textile-reinforced rubber, containing compressed air.
    • They are used to carry load on vehicles and provide elasticity or "springiness" when compressed.
    • Air springs have three characteristics: they are soft when unloaded, they increase stiffness when loaded, and they maintain constant vehicle height.
    • They provide optimum riding comfort in both lightly loaded and fully loaded conditions.

    Shock Absorber

    • Shock absorbers are used to control vibrations on springs, provide comfortable ride, and act flexible and rigid.
    • They are used as a part of the suspension system and provide more resistance to the motion of the spring and road wheel.
    • Types of shock absorbers include mechanical, hydraulic, and telescopic shock absorbers.

    Telescopic Shock Absorber

    • Construction consists of an upper eye attached to the axle, a lower eye attached to the chassis frame, and two-way valves.
    • Working involves fluid flowing between the valves to produce a damping force.
    • The damping force varies with the speed of the piston.

    Types of Suspension System

    • There are two basic types of suspension systems: front end suspension and rear end suspension.
    • Front end suspension types include independent front suspension and rigid axle front suspension.
    • Rear end suspension types include longitudinal leaf spring, transverse leaf spring, and coil spring rear end suspension.

    Independent Front Suspension

    • Developed in the 1930s to improve vehicle ride control and riding comfort.
    • Each front wheel is mounted on its own axle and independently supported by a coil or torsion bar or leaf spring.
    • Types of independent front suspensions include longitudinal, transverse, sliding, MacPherson Strut, parallelogram, trailing link, and vertical guide suspensions.

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    Description

    Learn about the key components and functions of a transmission system in automotive engineering, including the role of gears and shafts in transferring power from the engine to the wheels.

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