Braking systems

• Types of brakes:

  1. Block brake
  2. Contracting band brake
  3. Drum brake
  4. Disc brake
  5. ABS (Anti-lock braking system)
  6. Engine and exhaust brake
  7. Regenerative braking systems
  8. Hand brake
• Block brake included a sacrificial material (the wood) which acted towards providing friction for braking. This is because wood was cheaper and easier to get than rubber.
• The contracting band brakes includes a band surrounding a wheel which contracts through mechanisms. Through this contraction in the outer surface of the wheel, the band brake is able to retard the wheel through friction
• The drum brakes features an interior design in the wheel and includes two main shoes which can push to create friction inside the wheel. This is done through hydraulics mechanisms.
• The ABS or Anti-Lock Brake System prevents wheels from locking up during hard braking by modulating the pressure applied to the brakes. It does so by using sensors on each wheel to detect when they're about to skid and then releasing some of the pressure on those wheels while maintaining pressure on others.
• An engine brake uses the energy produced by the combustion process to slow down the vehicle. The engine brake works by reducing fuel flow into the cylinders, causing them to run at lower RPMs and produce less power. This reduces the amount of work being done by the engine, resulting in slower acceleration and deceleration.
• Exhaust brakes are used primarily in heavy vehicles such as trucks and buses. They work by restricting the flow of exhaust gases out of the engine, causing backpressure within the cylinders. This reduces the amount of air that enters the engine, decreasing its output of power.
• A regenerative braking system recovers kinetic energy that would otherwise be lost during braking and converts it back into electrical energy that can be used to recharge the battery pack. Regenerative braking systems are found in electric vehicles as well as hybrid cars with internal combustion engines.
• Electronic stability control (ESC) is a safety feature designed to prevent loss of traction and oversteer/understeer situations. ESC monitors the speed of each wheel and compares it to the steering angle and yaw rate of the vehicle. If one or more wheels begin to spin excessively, the ESC will apply individual brakes to bring the vehicle back into line.
• A handbrake is a mechanical device designed to hold a car stationary without the use of the foot pedals. Handbrakes typically consist of a lever attached to a cable or rod that pulls against the rear wheels of the car, preventing them from rolling forward or backward.
• The disc brakes are similar to the drum brakes but instead of having a drum shape, it has a flat circular shape with pads that press against the rotor.
• Hand brakes are oftentimes referred to as parking brakes
• There is an option to use the conventional brakes in a hybrid car if the brakes are pressed harder. This ensures less wear for the brakes as the regenerative braking system provides brakage.
• In regenerative braking, the electrical motor further provides resistive mechanical energy to the wheels/rotor.
• Disadvantages of contracting band brakes:

  • cannot perform/perform well on faster/heavier cars since more braking force is needed.
  • The friction of the band can easily wear off
  • Friction lining is subjected too natural forces
  • When reversing, the servo assistance acts against the desired motion
• Drum brake advantages:

  • Friction lining is away from natural forces since the shoes are inside
  • The servo-system can accomodate for reversing vehivles due to the front and back shoes
  • Two leading edge shoes can be utilised to increase efficiency
• Drum brake disadvantages:

  • Poor heat dissipation since brakes are inside he moving vehicle
  • SInce water can flow inside the system, frictional resistance can be highly reduced.
• Disc brakes use hydraulic operations from the brake system to trigger tension on the pads through the caliper, creating frictional resistance.
• Disc brake advantages:

  • Better heat dissipation
  • Better wet-weather performance due to centrifugal forces
• Disc brake disadvantages:

  • No servo assistance
  • Vacuum booster achieves higher reduction to the pedal instead.
  • Can result in brake wear across descents
  • If vacuum booster fails, a lot of force is required to stop the vehicle.
• ABS Advantages:

  • Improves car handling in challenging situations
  • During acceleration, when the vehicle turns, the change in traction control provides a smoother turn
• The ABS braking system doesn't perform as well on gravel roads since the car usually has to dig through the gravel rather than drive over it
• Exhaust and Engine brakes can work with disc brakes to ensure that the brakes don't fade through excess wear.
• In engine brakes, the engine has a tendancy to retard the vehicle under a rolling force without acceleration due to auxiliary brakes.
• Regenerative braking system advantages:

  • Environmentally friendly since energy is being conserved rather than wasted into heat energy
  • Does include a feature for conventional brakes, reducing wear in them
• The hand brake is effective with disk brakes and acts as an external braking unit in case of the hydraulic braking system failure.