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REGENERATIVE BRAKING

9th July, 2024

REGENERATIVE BRAKING

Source: Hindu

Disclaimer: Copyright infringement not intended.

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)