VEHICLE SKID VEHICLE SKID CONTROLCONTROL

PRESENTED BY:PRESENTED BY: MOAYANGER JAMIR.MOAYANGER JAMIR.

S7 MECH. ENGG.S7 MECH. ENGG. ROLL NO.32 ROLL NO.32

INTRODUCTIONINTRODUCTION

Vehicle skid - The loss of traction Vehicle skid - The loss of traction between a vehicle’s tyres and the road between a vehicle’s tyres and the road surface. surface.

VSC - Passive Technology.VSC - Passive Technology. VSC - To counter skids and prevent VSC - To counter skids and prevent

accidents. accidents.

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.

UNDERSTEERUNDERSTEER

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

OVERSTEEROVERSTEER

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

TYPES OF SKIDSTYPES OF SKIDS

The front wheel skid. The front wheel skid. The rear wheel skid.The rear wheel skid.

The four wheel skid The four wheel skid

FRONT WHEEL SKIDFRONT WHEEL SKID The car tends to take a course outside of the The car tends to take a course outside of the

expected course that the driver has steered expected course that the driver has steered (understeer). (understeer).

Understeer occurs when the front slip angle is Understeer occurs when the front slip angle is greater than the rear and the car goes straighter greater 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 or Excess speed on entry to a hazard i.e. a corner or bend, or sudden braking to reduce the speed when bend, or sudden braking to reduce the speed when negotiating the hazard. Both of these actions will negotiating the hazard. Both of these actions will have the effect of destabilizing the vehicle making it have the effect of destabilizing the vehicle making it more vulnerable to a loss of controlmore vulnerable to a loss of control..

REAR WHEEL SKIDREAR WHEEL SKID The rear of vehicle swings out of line and gives the The rear of vehicle swings out of line and gives the

impression of trying to overtake the front (oversteer).impression of trying to overtake the front (oversteer).

Oversteer occurs when the rear tyres have a greater Oversteer occurs when the rear tyres have a greater slip angle than the front tyres and the back threatens slip angle than the front tyres and the back threatens to overtake the front, causing the vehicle to spin. to overtake the front, causing the vehicle to spin.

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

FOUR WHEEL SKIDFOUR WHEEL SKID

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

Both front and rear wheel skids, if unchecked Both front and rear wheel skids, if unchecked sufficiently early, can develop into four wheel skids.sufficiently early, can develop into four wheel skids.

Harsh or sudden braking causing the wheels to lock Harsh or sudden braking causing the wheels to lock and a sensation of increase in the vehicle’s speed and a sensation of increase in the vehicle’s speed are the main causes.are the main causes.

SKID CONTROLSKID CONTROL To sense the onset of traction loss and keep To sense the onset of traction loss and keep

the driver on track.the driver on track. To deliver transparent intervention the To deliver transparent intervention the

moment the situation becomes unstable. moment the situation becomes unstable. Integrated with the engine management Integrated with the engine management

system to cut power even in tricky situations.system to cut power even in tricky situations. The system automatically applies selective The system automatically applies selective

braking to specific wheels to stabilize the braking to specific wheels to stabilize the vehicle. vehicle.

SKID CONTROL

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.

WORKINGWORKING It monitors information from the steering It monitors information from the steering

wheel, tyres, brakes and accelerator.wheel, tyres, brakes and accelerator. By combining datas from the various By combining datas from the various

sensors, the central processing unit can sensors, the central processing unit can detect when a vehicle is in a stable or detect when a vehicle is in a stable or unstable state.unstable state.

Automatically applies light brake pressure to Automatically applies light brake pressure to a select wheel (or wheels) and control the a select wheel (or wheels) and control the throttle to maintain or restore control.throttle to maintain or restore control.

ADVANTAGESADVANTAGES Monitors each wheel independently Monitors each wheel independently

maximizing the performance of the car to maximizing the performance of the car to optimize the cars handling ability. optimize the cars handling ability.

Increases comfort, both physical and Increases comfort, both physical and psychological. psychological.

Improves safety aspects of the car and the Improves 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 renegade Enhances the ability to dodge a renegade

object in its pathwaysobject in its pathways..

DISADVANTAGESDISADVANTAGES High initial costs.High initial costs.

Overdependence.Overdependence.

Not perfect.Not perfect.

Repairing cost may be high.Repairing cost may be high.

REMEDIAL MEASURESREMEDIAL MEASURES By decelerating.By decelerating. Relaxation of the pressure on the brake Relaxation of the pressure on the brake

pedal.pedal. Depressing the clutch pedal. Depressing the clutch pedal.

CONCLUSIONCONCLUSION Safety is the principal benefit of Vehicle Skid Safety is the principal benefit of Vehicle Skid

Control. Control. It does not guarantee the elimination of It does not guarantee the elimination of

accidents but lowers the percentage of accidents but lowers the percentage of crashes thereby lowering the number of crashes thereby lowering the number of fatalities. fatalities.

The latest generation of stability control The latest generation of stability control systems offer drivers increased protection for systems offer drivers increased protection for both themselves and the vehicle, they can both themselves and the vehicle, they can never overcome poor judgements or the laws never overcome poor judgements or the laws of physics.of physics.