vehicle skid control full report

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VEHICLE SKID CONTROL
PRESENTED BY:
MOAYANGER JAMIR.
S7 MECH. ENGG.
ROLL NO.32

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INTRODUCTION

Vehicle skid - The loss of traction between a vehicle’s tyres and the road surface.
VSC - Passive Technology.
VSC - To counter skids and prevent accidents.
CAUSES
Harsh or sudden acceleration.

Excessive or sudden braking.

Coarse or jerky steering movements.

Oversteer and understeer.
UNDERSTEER
When a car understeers, the front end of the car slides to the outside of a turn instead of taking the turn. Understeer occurs when the rear tyres have more traction than the front tyres, which often happens with frontwheel drive cars.
OVERSTEER
A car that oversteers turns very sharply, moving the rear of the car to slide outside of a corner while its front points towards the inside. Oversteer occurs when a car’s front tyres have more traction than the rear tyres, particularly with rear wheel drive cars.
TYPES OF SKIDS
The front wheel skid.

The rear wheel skid.

The four wheel skid
FRONT WHEEL SKID
The car tends to take a course outside of the expected course that the driver has steered (understeer).

Understeer occurs when the front slip angle is greater than the rear and the car goes straighter rather than following the intended turn.

Excess speed on entry to a hazard i.e. a corner or bend, or sudden braking to reduce the speed when negotiating the hazard. Both of these actions will have the effect of destabilizing the vehicle making it more vulnerable to a loss of control.

REAR WHEEL SKID
The rear of vehicle swings out of line and gives the impression of trying to overtake the front (oversteer).
Oversteer occurs when the rear tyres have a greater slip angle than the front tyres and the back threatens to overtake the front, causing the vehicle to spin.

Excessive speed into the hazard and sudden braking or acceleration with a rear wheel drive vehicle, destabilizing the vehicle, are the main causes of this skid.

FOUR WHEEL SKID
All four wheels have locked up and the vehicle is sliding in the direction that the forward momentum is carrying it, with no directional control.

Both front and rear wheel skids, if unchecked sufficiently early, can develop into four wheel skids.
Harsh or sudden braking causing the wheels to lock and a sensation of increase in the vehicle’s speed are the main causes.


SKID CONTROL
To sense the onset of traction loss and keep the driver on track.
To deliver transparent intervention the moment the situation becomes unstable.
Integrated with the engine management system to cut power even in tricky situations.
The system automatically applies selective braking to specific wheels to stabilize the vehicle.
SKID CONTROL
COMPONENTS
Yaw rate sensor.
G-sensor.
Steering angle sensor.
Electronic throttle control.
Slip indicator.
Computer.

WORKING
It monitors information from the steering wheel, tyres, brakes and accelerator.
By combining datas from the various sensors, the central processing unit can detect when a vehicle is in a stable or unstable state.
Automatically applies light brake pressure to a select wheel (or wheels) and control the throttle to maintain or restore control.

ADVANTAGES
Monitors each wheel independently maximizing the performance of the car to optimize the cars handling ability.
Increases comfort, both physical and psychological.
Improves safety aspects of the car and the driver.
Helps save money long term.
Enhances the ability to dodge a renegade object in its pathways.
DISADVANTAGES
High initial costs.

Overdependence.

Not perfect.

Repairing cost may be high.


REMEDIAL MEASURES
By decelerating.

Relaxation of the pressure on the brake pedal.

Depressing the clutch pedal.
CONCLUSION
Safety is the principal benefit of Vehicle Skid Control.
It does not guarantee the elimination of accidents but lowers the percentage of crashes thereby lowering the number of fatalities.
The latest generation of stability control systems offer drivers increased protection for both themselves and the vehicle, they can never overcome poor judgements or the laws of physics.