This document discusses vehicle skid control systems. It defines vehicle skids and explains their causes such as harsh braking or acceleration. It describes types of skids like understeer, oversteer, and four-wheel skids. The document outlines how vehicle skid control systems work by using sensors to detect instability and selectively applying brakes to stabilize the vehicle. It notes benefits like improved safety and handling and lists some costs and limitations of these systems.

1. VEHICLE SKIDVEHICLE SKID
CONTROLCONTROL
PRESENTED BY:PRESENTED BY:
MOAYANGER JAMIR.MOAYANGER JAMIR.
S7 MECH. ENGG.S7 MECH. ENGG.
ROLL NO.32ROLL NO.32

2. INTRODUCTIONINTRODUCTION
 Vehicle skid - The loss of tractionVehicle skid - The loss of traction
between a vehicle’s tyres and the roadbetween a vehicle’s tyres and the road
surface.surface.
 VSC - Passive Technology.VSC - Passive Technology.
 VSC - To counter skids and preventVSC - To counter skids and prevent
accidents.accidents.

3. CAUSESCAUSES
 Harsh or sudden acceleration.Harsh or sudden acceleration.
 Excessive or sudden braking.Excessive or sudden braking.
 Coarse or jerky steering movements.Coarse or jerky steering movements.
 Oversteer and understeer.Oversteer and understeer.

4. UNDERSTEERUNDERSTEER
When a car understeers, the front end ofWhen a car understeers, the front end of
the car slides to the outside of a turnthe car slides to the outside of a turn
instead of taking the turn. Understeerinstead of taking the turn. Understeer
occurs when the rear tyres have moreoccurs when the rear tyres have more
traction than the front tyres, which oftentraction than the front tyres, which often
happens with frontwheel drive cars.happens with frontwheel drive cars.

5. OVERSTEEROVERSTEER
A car that oversteers turns very sharply,A car that oversteers turns very sharply,
moving the rear of the car to slide outsidemoving the rear of the car to slide outside
of a corner while its front points towardsof a corner while its front points towards
the inside. Oversteer occurs when a car’sthe inside. Oversteer occurs when a car’s
front tyres have more traction than thefront tyres have more traction than the
rear tyres, particularly with rear wheelrear tyres, particularly with rear wheel
drive cars.drive cars.

6. TYPES OF SKIDSTYPES OF SKIDS
 The front wheel skid.The front wheel skid.
 The rear wheel skid.The rear wheel skid.
 The four wheel skidThe four wheel skid

7. FRONT WHEEL SKIDFRONT WHEEL SKID
 The car tends to take a course outside of theThe car tends to take a course outside of the
expected course that the driver has steeredexpected course that the driver has steered
(understeer).(understeer).
 Understeer occurs when the front slip angle isUndersteer occurs when the front slip angle is
greater than the rear and the car goes straightergreater than the rear and the car goes straighter
rather than following the intended turn.rather than following the intended turn.
 Excess speed on entry to a hazard i.e. a corner orExcess speed on entry to a hazard i.e. a corner or
bend, or sudden braking to reduce the speed whenbend, or sudden braking to reduce the speed when
negotiating the hazard. Both of these actions willnegotiating the hazard. Both of these actions will
have the effect of destabilizing the vehicle making ithave the effect of destabilizing the vehicle making it
more vulnerable to a loss of controlmore vulnerable to a loss of control..

9. REAR WHEEL SKIDREAR WHEEL SKID
 The rear of vehicle swings out of line andThe rear of vehicle swings out of line and
gives the impression of trying to overtake thegives the impression of trying to overtake the
front (oversteer).front (oversteer).
 Oversteer occurs when the rear tyres have aOversteer occurs when the rear tyres have a
greater slip angle than the front tyres and thegreater slip angle than the front tyres and the
back threatens to overtake the front, causingback threatens to overtake the front, causing
the vehicle to spin.the vehicle to spin.
 Excessive speed into the hazard and suddenExcessive speed into the hazard and sudden
braking or acceleration with a rear wheelbraking or acceleration with a rear wheel
drive vehicle, destabilizing the vehicle, aredrive vehicle, destabilizing the vehicle, are
the main causes of this skid.the main causes of this skid.

11. FOUR WHEEL SKIDFOUR WHEEL SKID
 All four wheels have locked up and theAll four wheels have locked up and the
vehicle is sliding in the direction that thevehicle is sliding in the direction that the
forward momentum is carrying it, with noforward momentum is carrying it, with no
directional control.directional control.
 Both front and rear wheel skids, if uncheckedBoth front and rear wheel skids, if unchecked
sufficiently early, can develop into four wheelsufficiently early, can develop into four wheel
skids.skids.
 Harsh or sudden braking causing the wheelsHarsh or sudden braking causing the wheels
to lock and a sensation of increase in theto lock and a sensation of increase in the
vehicle’s speed are the main causes.vehicle’s speed are the main causes.

13. SKID CONTROLSKID CONTROL
 To sense the onset of traction loss and keepTo sense the onset of traction loss and keep
the driver on track.the driver on track.
 To deliver transparent intervention theTo deliver transparent intervention the
moment the situation becomes unstable.moment the situation becomes unstable.
 Integrated with the engine managementIntegrated with the engine management
system to cut power even in tricky situations.system to cut power even in tricky situations.
 The system automatically applies selectiveThe system automatically applies selective
braking to specific wheels to stabilize thebraking to specific wheels to stabilize the
vehicle.vehicle.

14. SKID CONTROL

15. COMPONENTSCOMPONENTS
 Yaw rate sensor.Yaw rate sensor.
 G-sensor.G-sensor.
 Steering angle sensor.Steering angle sensor.
 Electronic throttle control.Electronic throttle control.
 Slip indicator.Slip indicator.
 Computer.Computer.

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

18. ADVANTAGESADVANTAGES
 Monitors each wheel independentlyMonitors each wheel independently
maximizing the performance of the car tomaximizing the performance of the car to
optimize the cars handling ability.optimize the cars handling ability.
 Increases comfort, both physical andIncreases comfort, both physical and
psychological.psychological.
 Improves safety aspects of the car and theImproves safety aspects of the car and the
driver.driver.
 Helps save money long term.Helps save money long term.
 Enhances the ability to dodge a renegadeEnhances the ability to dodge a renegade
object in its pathwaysobject in its pathways..

19. DISADVANTAGESDISADVANTAGES
 High initial costs.High initial costs.
 Overdependence.Overdependence.
 Not perfect.Not perfect.
 Repairing cost may be high.Repairing cost may be high.

20. REMEDIAL MEASURESREMEDIAL MEASURES
 By decelerating.By decelerating.
 Relaxation of the pressure on the brakeRelaxation of the pressure on the brake
pedal.pedal.
 Depressing the clutch pedal.Depressing the clutch pedal.

21. CONCLUSIONCONCLUSION
 Safety is the principal benefit of Vehicle SkidSafety is the principal benefit of Vehicle Skid
Control.Control.
 It does not guarantee the elimination ofIt does not guarantee the elimination of
accidents but lowers the percentage ofaccidents but lowers the percentage of
crashes thereby lowering the number ofcrashes thereby lowering the number of
fatalities.fatalities.
 The latest generation of stability controlThe latest generation of stability control
systems offer drivers increased protection forsystems offer drivers increased protection for
both themselves and the vehicle, they canboth themselves and the vehicle, they can
never overcome poor judgements or the lawsnever overcome poor judgements or the laws
of physics.of physics.