ABS ,CBS & EBD

What is ABS ,CBS & EBD ?

Here’s a fact: India has the highest road fatalities in the world. Road accidents in India have claimed 147,913 lives in 2017 and left 470,975 injured. While the numbers are simply shameful, there is hope that our roads could get a bit safer thanks to the new two-wheeler and four-wheeler safety norms that came into effect from April 1,2019 .

All four- and two-wheelers manufactured in the country will have to be compulsorily fitted with ABS or an Anti-Lock Braking System. As per the norms, all new two-wheelers with an engine displacement over 125cc will have to be equipped with ABS while models with engine displacement of 125cc or below will need to have compulsory fitment of combi-braking system (CBS).

Let's have a look ,what does this ABS ,CBS & EBD terms actually means .

What Is ABS ?

Anti-Lock braking System system or ABS is a safety system which prevents the wheels on a moving vehicle from locking up(or cease while rotating) while braking. ABS offers improved vehicle control over dry and especially slippery surfaces by reducing the braking distance but it can also increase the braking distance in case of loose surfaces like snow, gravel etc.

• Working Of ABS

When brakes are applied under heavy loads,  the braking pressure becomes high resulting in heavy braking or in other words locking up of wheels. The ABS overcomes this by monitoring the wheel speed and releases pressure on each wheel brake lines in the form of rapid pulses switching between different brake lines. which prevent locking-up. Preventing lock-up under heavy braking helps the driver in maintaining control over the vehicle. In modern ABS an individual brake line is provided for each of the four wheel enabling different braking pressures for different road surfaces of the wheels.

What is CBS ?

Combined braking system or ‘CBS’ was pioneered by Honda in the 1970’s. In India, it was implemented on the Honda Activa in 2009 and has since been one of the most effective ways of braking for novice riders. It’s a well-known fact that the most effective way of braking is to apply both the front and the rear brake simultaneously. However, this only comes with practice and patience, which most riders do not have. Fortunately, Honda introduced the CBS system which applies brake force at both ends by just pulling on the rear brake lever.

Unlike ABS though, a CBS system won't affect braking distance -- it only reduces the rider reaction time. Braking distance mostly rely on good brakes and sticky tyres. As per our tests, the braking distance is longer while using CBS because the brake force is not equally distributed. In fact, the front brake only operates when the brake lever passes a certain threshold, which triggers the delay valve to open up, post which the pressure control valve (PCV) starts to close, reducing the pressure on the rear brake. So, equally distributed brake force may not be entirely true in case of CBS. That said, it still allows novice riders to brake in a reasonably shorter distance than they would on a non-CBS bike. Notably, Honda’s CBS system works on both disc/ drum as well as drum/drum brake setups, as compared to ABS which only works with disc brakes.

What Is EBD ?

Electronic brake- force distribution system also called as Electronic brake-force limitation is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle’s brakes, based on road conditions, speed, loading, etc.

EBD system is  always coupled with anti-lock brake-force system. The most important function of EBD is to maintain vehicular control with variation in braking pressure applied to each wheel in order to maximize stopping power. Generally most of the weight of all vehicles is carried by the front end so the EBD ensures less braking pressure at the rear end to avoid skidding. But in some EBD’s the distribution of braking pressure at the rear end is more initially when the brakes are applied  before the effects of weight transfer comes into play.

• Working of EBD system

An EBD is a subsystem of the abs and its function is to control the effective adhesion utilization by the rear wheels.

The Antilock brake force system releases pressure in different brake lines at the time of heavy braking to prevent locking-up. The action comes in the form of releasing pressure from the braking circuit when it detects extreme and rapid deceleration in any of the four wheels in order to make sure that the driver maintains control over the steering during panic or emergency braking. For example if the wheels of a vehicle are on snow as well as asphalt then in case of emergency braking the ABS will monitor the speeds and eventually the EBD system will release less pressure for wheels on snow and more pressure for wheels on asphalt to prevent wheel lock-up.