Early Braking Systems

PRESENTATION TOPIC ABS

( Anti-lock Brake System )Group MembersAmmar Majeed Butt (Intro) (2011-ME-183)

Muhammad Rehan (Components)(2011-ME-210)

Hafiz Faran Baig (Working)(2011-ME-194)

Asad Shaukat Ali (Types)(2011-ME-186)Lets have a short glimpse of

HISTORYBRAKING SYSTEMS IN CARSOne of the most essential systems of the carUsed to: Stop the moving the car

Different types of braking systems have been used in the cars and engineers have been working to improve this system from that very day when the car started to moveEarly Braking SystemsDrum Brakes

Used a drum designComponents housed inside a round drumBasic component was a set of shoesMechanism Main disadvantage

Disc brakes

Use calipers on either side of the spinning discBrake pads within the calipersMechanism Advantage over drum brakes

PROBLEMS WITH THESE SYSTEMSNot very efficientTake time to stop a fast moving carThe car skids off when sudden brakes are applied in fast speed REASON OF SKIDDINGAt a high speed the car has some momentumBrakes applied: As a result

Wheels tend to stop But car (due to momentum) keeps on moving Relative motion between the wheels and the car This scenario locks up the wheels

ABS

(Anti-lock Brakes System)WHAT ARE ANTI-LOCK BRAKES?ABS (Anti-lock Brakes System) is the most efficient braking system used in the vehicles now-a-days

These brakes allow the driver to stop a fast moving car :Efficientlyin a very short interval of timeWithout skidding off

COMPONENTS AND WORKING OF ABSCOMPONENTSFour major componentsSpeed Sensors

Valves

Pump

ECU (Engine Control Unit) or The Controller

Speed SensorsLocated in each wheelSense when the wheel is going to lockSend the information to ECU

ValvesPresent in brake line of each brake

Used to take off the pressure from the brake calipers

PumpPresent in the brake line

Pumps the pressure back onto the calipers

ECU (Engine Control Unit) ORABS CONTROLLERCan be regarded as the BRAIN of a car

A computer which:Receives information from different components commands all the components of various systems accordingly

COMPONENTS AND WORKING OF ABSWORKINGThe controller monitors the speed sensors all the times

When sudden brakes are applied, before a wheel locks up, it will experience a rapid deceleration

A locked-up wheel stops immediately and spins the car

Before the wheel locks up, i-e before it rapidly decelerates, the ABS controller commands the corresponding valve to reduce the pressure This accelerates that wheel

The controller then commands the pump to increase the pressure again until it is going to decelerate againThen it commands the valve to decrease the pressureThe process is repeated again and again

Note: It can do this very quickly, before the tire can actually significantly change speed. The result is that the wheel slows down at the same rate as the car, with the brakes keeping the tires very near the point at which they will start to lock up

This gives the system MAXIMUM braking powerWorking of ABS (Schematic Diagram)

When the ABS system is in operation:the driver will feel a pulsing in the brake pedalthis comes from the rapid opening and closing of the valves

! Some ABS systems can cycle up to 16 times per second

BRAKE TYPESOne-channel, one-sensor ABS

It has one valve, which controls both rear wheels

one speed sensor located in the rear axle

The rear wheels are monitored together and they both have to start to lock up before the ABS kicks in24

Three-channel, three-sensor ABS

This is four-wheel ABS

commonly found on pickup trucks

a speed sensor and a valve for each of the front wheels

one valve and one sensor for both rear wheels

Three-channel, four-sensor ABS

a speed sensor on all four wheels

a separate valve for each of the front wheels

only one valve for both of the rear wheelsFour-channel, four-sensor ABS

There is a speed sensor on all four wheels and a separate valve for all four wheels

the controller monitors each wheel individually to make sure it is achieving maximum braking force

This is the best schemeABS in PakistanFollowing cars of different companies have ABS in them

Corolla GliAltisGli 1.6

HondaCityCivicAccord

SuzukiSwiftLiana lxiEminent

ChevroletOptra

EFFECTIVENESSA 2003Australianstudy by Monash University Accident Research Centre found that ABS:

Reduced the risk of multiple vehicle crashes by 18 percentReduced the risk of run-off-road crashes by 35 percent

(Reference:http://en.wikipedia.org/wiki/Anti-lock_braking_system#cite_note-17A June 1999National Highway Traffic Safety Administration(NHTSA) study found that ABS increased stopping distances on loose gravel by an average of 22 percent

(Reference:http://en.wikipedia.org/wiki/Anti-lock_braking_system#cite_note-17)ABS manufacturers formed their own group called the ABS Education Alliance and their study showed that 4-wheel ABS cars had 2800 fewer front-end collisions than regular cars during the same time-period

(Reference:Antilock Brake System Safety | eHow.comhttp://www.ehow.com/way_5782168_antilock-brake-system-safety.html#ixzz1u0xg6W4T)SUMMARYABS is the most efficient braking system until now

It makes driving easier

It HAS saved many lives and is considered to save many in future

Margin for improvement is and will be there

The fight for improvement in technology is fought by us

ENGINEERS

This is who we are..!! THANKS