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Other than airbags, what other safety features do a good car provide?

01 Sep 2007 | Category: Car Technical Advice

Airbag

An airbag is an inflatable cushion that protects the driver and passengers from serious injury in cases of collision. It supplements the safety belt by reducing the chance that the occupant's head and upper body will strike the same part of the vehicle's interior. Airbags also help reduce the risk of serious injury by distributing crash forces more evenly across the occupant's body.

To ensure that the airbags are still in working condition despite being unused, the air bag circuitry performs an internal self-test during each start up. It is usually indicated by a light on the instrument panel that glows briefly at each engine start up.

Airbag protects occupants in the car from serious injuries
Note:
Do not place any objects on your dashboard. When the airbag is deployed, the objects become lethal projectiles.
Keep children away from the airbag deployment area as the airbags may cause suffocation or injuries.

Anti-Lock Braking System (ABS)

Anti-lock braking system (ABS) allows a driver to gain control of the vehicle and avoid skidding while the vehicle is braking. It was first developed in 1978 by Bosch.

How it Works
There are 4 components in the ABS system- speed sensors, the pump, valves and the controller. ABS uses the speed sensors to determine if any of the wheels are trying to lock up during braking. If a wheel tries to lock up, a series of hydraulic valves (activated by the controllers) reduce the braking on that wheel. This explains why ABS prevents skidding and allows you to maintain steering control. Thereafter, the pump serves to increase pressure on the wheel so that the wheel will come to an eventual halt.

ABS is rarely activated unless the driver has to deal with an emergency brake. The vibration that you feel in the brake pedal comes from the rapid opening and closing of the valves.

During emergency braking, it is important to apply a steady and constant pressure while steering to avoid the road hazards. Do not take your foot off the brake pedal until the vehicle has stopped.
ABS prevents locking of the wheel and allows you to steer your vehicle during an emergency brake.
Brake Assist

Brake assist is a driver-adaptive system which learns each driver's braking habits by using electronic sensors to monitor every movement of the brake pedal and feeding this information into a mini-computer. The computer senses emergency braking by detecting the speed at which the driver presses the brake pedal, after which it immediately applys all available brake force.

Brake Assist can potentially reduce overall stopping distance by eliminating the delay caused by a common human tendency of not braking hard or soon enough.

Mercedes-Benz has developed a system which shortens emergency stopping distance should a driver not apply brakes hard enough in critical situations. The system automatically develops maximum brake boost with split-second speed, thus reducing the stopping distance by a significant margin.
Brake Assist applies extra pressure on your brakes

Electronic Brake Distribution (EBD)

Electronic brake distribution is an additional feature of the more sophisticated ABS braking systems, An electronic control system measures parameters such as road conditions, speed, loading, etc to distribute braking force more effectively.

Most braking systems distribute brake force equally through all 4 wheels by mechanical control. EBD applies brake force precisely through electronic control. It recognises that driving conditions, braking situations and vehicle weight distributions are unique and constantly changing. Working together with Anti-lock Braking System (ABS), EBD uses sensors to determine which wheels would provide maximum braking for the conditions. The final result is more precise and effective braking under all conditions.

How it works
Example of EBD when braking in a straight line

When applying brakes while moving forward, the rear wheels carry less weight as compared to the front wheels. Without EBD, the brake force would be evenly distributed throughout all 4 wheels, causing the rear wheels to lock and the vehicle to skid. With EBD, the brake force to the rear wheels is applied precisely by electronic control, reducing the chance of locking.
EBD allows you to maintain traction to the ground even during emergency braking

Traction Control
Traction Control is used to prevent the drive wheels from losing grip when accelerating.

Spinning tyres during hard acceleration may be dramatic, but it is the slowest way to get to your desired speed. Using the car's ABS speed sensors at the wheels, the Traction Control computer compares the drive wheel's speed to the car's road speed. If there is a loss of grip event during acceleration, there are a number of ways that the Traction Control slows the drive wheels so they can regain grip.

The most common method is to use the braking system. When the drive wheels lose grip, the ABS computer can apply the brake to the wheel that has lost grip to slow it down so it can regain grip.

Another method for slowing the slipping wheels is to reduce the amount of power applied to them. The computer will electronically modify the amount of fuel entering the engine and/or use the transmission to slow the drive wheels so they can regain grip.
Car tyres are more likely to spin under wet conditions

Stability Control
Stability Control is used to prevent a car from sliding sideways when making a turn. It is particularly effective when driving in rainy weather.

Stability Control works by using a rotational speed sensor to check for skidding when the car is making a turn. This information is then fed into a microcomputer that correlates the data with wheel speed, steering angle and accelerator position. The appropriate braking force is then applied to the appropriate wheels

Theoretically speaking, vehicles equipped with stability control do not require drivers to brake when making turns Drivers have to control the steering wheel while the stability control device does the braking for you.

Below are some of the different names used by car manufacturers for their stability control systems.
• Audi: Electronic Stability Program (ESP)
• BMW: Dynamic Stability Control (DSC)
• DaimlerChrysler: Electronic Stability Program (ESP)
• Ford Motor Company: Advance Trac
• Jaguar: Dynamic Stability Control (DSM)
• Lexus: Vehicle Skid Control (VSC)
• Volkswagen: Electronic Stability Program (ESP)
• Volvo: Dynamic Stability Traction Control (DTSC)
Stability control is very useful when turning on wet ground
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