Wheels India

ABS and EBD !!

2005-12-29T17:00:00.000+05:30

anti-lock braking system and Electronic brakeforce distribution...

ABS 'anti-lock braking system' -
An anti-lock braking system (commonly known as ABS, from the German name "Antiblockiersystem" given to it by its inventors at Bosch) is a system on motor vehicles which prevents the wheels from locking while braking. The purpose of this is twofold: to allow the driver to maintain steering control and to shorten braking distances (by allowing the driver to fully hit the brake without the fear for skidding or the loss of control).Unlike traditional brakes which can lock-up when applied in an emergency, cars fitted with ABS can be steered throughout the braking process. By using a pulsating grip and release' effect, the driver of the car is able to steer around an obstacle, rather than lock-up the wheels.It is particularly successful during poor traction conditions, such as during wet weather or on unsealed roads. ABS brake systems have speed sensors that measure wheel speed and relay this information to an electronic control unit.A computer calculates the slip, or difference between the speed of the wheel and the speed of the car. When it determines that a wheel is about to lock, the computer sends signals to hydraulic valves, which regulate the brake pressure at each wheel to prevent wheel lock-up.
EBD 'Electronic brakeforce distribution'
- Electronic Brake Force Distribution or EBD is an automobile brake technology that automatically varies the amount of force applied to each of a vehicles brakes. Often coupled with Anti-lock braking systems, EBD can apply more or less braking pressure to each wheel in order to maximize stopping power.
Tags: Technical . Car . EBD . ABS

Electronic Stability Control (ESC) !!

2005-12-29T15:32:00.000+05:30

- Electronic Stability Control (ESC) is the generic term for systems designed to improve a vehicle's handling, particularly at the limits where the driver might lose control of the vehicle.Electronic Stability Control (ESC) is a stability enhancement system designed to electronically detect and assist drivers in critical driving situations and under adverse conditions automatically.Robert Bosch GmbH were the first to deploy an ESC system, called Elektronisches Stabilitätsprogramm (ESP) that was used first by Mercedes-Benz and BMW in 1995.ESC compares the driver's intended direction in steering and braking inputs, to the vehicle's response, via lateral acceleration, rotation (yaw) and individual wheel speeds. ESC then brakes individual front or rear wheels and/or reduces excess engine power as needed to help correct understeer (plowing) or oversteer (fishtailing). ESC also integrates all-speed traction control, which senses drive-wheel slip under acceleration and individually brakes the slipping wheel or wheels, and/or reduces excess engine power, until control is regained. ESC cannot override a car's physical limits. If a driver pushes the possibilities of the car's chassis and ESC too far, ESC cannot prevent a crash. It is a tool to help the driver maintain control.

Vehicle manufacturers use electronic stability control systems under different marketing names:
BMW: Dynamic Stability Control (DSC), including Dynamic Traction Control
Daimler Chrysler: Electronic Stability Program (ESP)
Fiat: Electronic Stability Program (ESP)
Hyundai: Electronic Stability Program
Mercedes: Electronic Stability Program (ESP)
Suzuki: Vehicle Stability Control (VSC)
Toyota: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC) Mitsubishi: Active Skid and Traction Control MULTIMODE etc.
Tags: Technical . Cars . Electronic stability control

Traction control (Wikipedia) !!

2005-12-29T15:13:00.000+05:30

Traction control (TCS) - picked From Wikipedia, the free encyclopedia.
Traction control and Electronic Stability Control systems, on current productionvehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of control when excessive throttle or steering is applied by the driver.
The intervention can consist of any, or all, of the following:
*Retard or suppress the spark to one or more cylinders
*Reduce fuel supply to one or more cylinders
*Brake one or more wheels
*Close the throttle, if the vehicle is fitted with drive by wire throttle.
The brake actuator, and the wheel speed sensors, are the same as that used for Anti-lock braking system.
Traction Control is usually considered as a performance enhancement, allowing maximum traction under acceleration without wheel spin. It is also extremely useful in countries that suffer from icy or snowy roads: When driving up a slippery hill, giving full gas and letting the car's TCS take care of the throttle control will allow to scale slopes that are nigh-on impossible without TCS.
It is particularly advantageous to 4x4 vehicles when driven off road on a loose surface. Conversely Vehicle Stability Control is considered a safety feature preventing operation of a vehicle at the edge of the safety envelope.
It is widely thought that TC removes some skill and control from the driver. As such it is unpopular with many motorsports fans. Some motorsports series have given up trying to outlaw traction control, either because the general function is so hard to detect, egF1, or, as in many U.S. stock car series, because it is possible to incorporate an effective traction control device in the wiring, invisible to scrutineers.
Tags: Technical . Cars . Traction control . Car safety

NCAP Rating !!

2005-12-29T15:00:00.000+05:30

- Euro NCAP provides motoring consumers with a realistic and independent assessment of the safety performance of some of the most popular cars sold in Europe and world-wide.EuroNCAP, the European New Car Assessment Programme, is a safety assessment programme for automobiles supported by several European governments, many major manufacturers and motoring organisations across the world. EuroNCAP publishes safety reports on new cars and awards 'star ratings' based on the performance of the vehicles in a variety of crash tests, including front, side and rear impacts, and impacts with pedestrians.
EuroNCAP Official Website
Tags: Technical . Cars . NCAP . Car safety

Anti-Roll Bar !!

2005-12-29T14:44:00.000+05:30

Anti-roll or Stabilizer bars are part of a car's suspension system. They are sometimes also called anti-sway bars or anti-roll bars. Their purpose in life is to try to keep the car's body from "rolling" in a sharp turn.It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness (or roll couple/torque), its resistance to roll in turns, independent of its spring rate in the vertical direction.An anti-roll bar has a spring rate based on the length and diameter of the torsion bar and the geometry (and thus leverage) of its mounting points. Its principal effect is to resist roll towards the outside of a turn, keeping the body relatively flat.Think about what happens to a car in a sharp turn. If you are inside the car, you know that your body gets pulled toward the outside of the turn. The same thing is happening to all the parts of the car. So the part of the car on the outside of the turn gets pushed down toward the road and the part of the car on the inside of the turn rises up. In other words, the body of the car "rolls" 10 or 20 or 30 degrees toward the outside of the turn. If you take a turn fast enough, the tires on the inside of the turn actually rise off the road and the car flips over.
Roll is bad. It tends to put more weight on the outside tires and less weigh on the inside tires, reducing traction. It also messes up steering. What you would like is for the body of the car to remain flat through a turn so that the weight stays distributed evenly on all four tires.A stabilizer bar tries to keep the car's body flat by moving force from one side of the body to another. To picture how a stabilizer bar works, imagine a metal rod that is an inch or two (2 to 5 cm) in diameter. If your front tires are 5 feet (1.6 meters) apart, make the rod about 4 feet long. Attach the rod to the frame of the car in front of the front tires, but attach it with bushings in such a way that it can rotate. Now attach arms from the rod to the front suspension member on both sides. When you go into a turn now, the front suspension member of the outside of the turn gets pushed upward. The arm of the sway bar gets pushed upward, and this applies torsion to the rod. The torsion them moves the arm at the other end of the rod, and this causes the suspension on the other side of the car to compress as well. The car's body tends to stay flat in the turn.If you don't have a stabilizer bar, you tend to have a lot of trouble with body roll in a turn. If you have too much stabilizer bar, you tend to lose independence between the suspension members on both sides of the car. When one wheel hits a bump, the stabilizer bar transmits the bump to the other side of the car as well, which is not what you want. The ideal is to find a setting that reduces body roll but does not hurt the independence of the tires.
External Link: "How do stabilizer bars work?"
Tags: Technical . Cars . Anti-Roll Bar . automobile

Oversteer & Understeer !!

2005-12-29T13:50:00.000+05:30

Oversteer, in an automobile, occurs when the rear tires have a loss of traction during a cornering situation, thus causing the rear of the car to head towards the outside of the corner. The act of deliberately sending a car sideways through a series of corners is actually a popular form of motorsport that originated in Japan known as drifting. A more technically correct definition is that oversteer is the condition when the slip angle of the rear tires exceeds that of the front tires. Rear wheel drive cars are generally more prone to oversteer, in particular when applying power in a tight corner.
In an understeer situation, the front end of the car tends to slide out.Understeer is a term for a car handling condition during cornering in which the circular path of the vehicle's motion is of a greater diameter than the circle indicated by the direction its wheels are pointed.
Tags: Technical . CARS . stability control