Source: Hindu

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Context

• Recent efforts to lower emissions focus on reducing consumption and changing consumer habits.
• Electric vehicles (EVs), supported by government incentives, play a key role.
• Regenerative braking in EVs improves energy efficiency, promoting sustainable transportation.

Details

What is Braking?

• Braking is the mechanism by which a vehicle reduces its speed or comes to a stop.

Types of Brakes

Mechanical Brakes

• Disc Brakes:
  • Consist of brake pads pressing against a disc attached to wheels.
  • Friction converts kinetic energy into heat.
  • Holes in discs aid heat dissipation.
• Drum Brakes:
  • Brake shoes press against the inner surface of a drum attached to wheels.
  • Friction slows down wheels through heat generation.

Electromagnetic Brakes

• Induction Brakes:
  • Often used in trains.
  • Magnets induce electric currents in a conducting wheel.
  • Currents create a magnetic field that opposes the magnet’s field, slowing down the wheel.
  • Energy dissipated as heat due to resistance in the conductor.

Importance of Braking

• Vehicle Control:Enables safe speed adjustment and stopping.
• Safety:Prevents accidents by reducing speed effectively.
• Energy Management:Converts kinetic energy into heat or electrical resistance.

Regenerative Braking

• Regenerative braking is a system in electric and hybrid vehicles designed to convert the kinetic energy of the wheels into electrical energy, which is then stored in the vehicle’s battery.
• This system operates by using the electric motor as a generator during deceleration, thus reversing the motor's function.

Working Principle:

• Deceleration Detection: When the driver lifts off the accelerator or applies the brakes, the system detects the need to slow down.
• Motor as Generator: The traction motor switches from driving mode to generating mode.
• Energy Conversion: The kinetic energy from the moving vehicle is converted into electrical energy by the motor.
• Energy Storage: The electrical energy generated is stored in the vehicle's battery for later use.

Benefits:

• Energy Efficiency: Recovers energy that would otherwise be lost as heat in conventional braking.
• Extended Range: Increases the driving range of electric vehicles by reusing captured energy.
• Reduced Brake Wear: Decreases wear and tear on conventional brake components, leading to lower maintenance costs.
• Environmental Impact: Reduces emissions by improving energy use efficiency.

Downsides of Regenerative Braking:

• Not Sufficient for Complete Stops: Requires conventional brakes for complete halting.
• Limited Effectiveness at Low Speeds: Less kinetic energy available to convert into electrical energy.
• Brake Feel: Can differ from conventional brakes, potentially affecting driver comfort.
• Additional System Requirements: Needs integration with conventional braking systems to ensure safety and performance​​.

Comparison of Braking Systems

Feature	Regenerative Braking	Conventional Braking	Engine Braking
Mechanism	Converts kinetic energy to electrical energy, storing it in the battery	Uses friction to convert kinetic energy to heat	Utilizes engine compression to slow down the vehicle
Primary Use	Electric and hybrid vehicles	All types of vehicles	Primarily manual transmission vehicles
Energy Efficiency	High, recovers and reuses energy	Low, energy lost as heat	Moderate, uses engine’s internal resistance
Impact on Fuel/Energy Consumption	Reduces energy/fuel consumption by reusing captured energy	No significant impact on energy/fuel consumption	Reduces fuel injection during deceleration, saving fuel
Brake Wear and Tear	Reduces wear on friction brake components	High wear on brake pads and discs	Minimal impact on brake components
Performance at High Speeds	Less effective, may not capture all energy	Effective	Effective
Performance on Slippery Surfaces	Less effective due to reduced traction	Effective	Effective
Battery Dependency	Dependent on battery capacity; ineffective if battery is full	Not dependent on battery	Not dependent on battery
Maintenance Cost	Lower due to reduced brake wear	Higher due to frequent replacement of brake pads and discs	Lower, primarily engine maintenance
Complexity	High, requires integration with vehicle’s electrical system	Low, straightforward mechanical system	Moderate, depends on engine design
Environmental Impact	Positive, reduces emissions by improving energy efficiency	Neutral/Negative, no recovery of kinetic energy	Positive, reduces fuel usage during deceleration
Driver Experience	Different pedal feel; can require adjustment	Familiar feel for most drivers	Different pedal feel; requires adjustment, especially in automatics

 Other Energy Recovery Systems

• Flywheels: Stores kinetic energy by increasing angular momentum, useful in high-performance applications.
• Compressed Air: Uses recovered energy to compress air, which can start internal combustion engines.

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Sources:

Hindu

PRACTICE QUESTION Q: Regenerative braking complements conventional braking systems to provide a complete solution for vehicle deceleration and energy conservation. Comment. (150 Words)