CRUISE CONTROL KAMALA PRIYANKA VARANASI 08261A1456

Cruise control (sometimes known as speed control or auto cruise) is a system that automatically controls the speed of a motor vehicle. The system takes over the throttle of the car to maintain a steady speed as set by the driver.

Cruise Control System 1.Input: buttons on the steering wheel, brake, clutch, gas pedal and feedback signal 2.Processor 3.Sensor 4.Output: the throttle position

The basic principle used in cruise control system is the closed loop system.

WORKING The actuator is usually a vacuum powered device that uses engine manifold vacuum to provide the energy to set the throttle correctly. By monitoring time, the vehicle's speed and throttle position, the cruise control's Electronic Control Unit (ECU) commands an actuator to open or close the throttle to maintain the speed that the driver has selected  All cruise control systems monitor brake pedal position and turn off automatically if you put your foot on the brake. (Incidentally, even if the cruise control should fail in the on position and not turn off with a tap of the brake, the brakes themselves have more than enough authority to bring a modern vehicle to a complete stop even with the throttle fully open.)

TYPES There are two types of cruise control Manual Cruise Control Adaptive/Electrical Cruise Control Types of ACC: Radar-Based System Three overlapping radar-beams (76-77kHz) Detects moving object up to 120 m work in poor weather conditions Laser-Based System (lidar) less expensive and easier to package light beams are narrower than water droplet and snowflakes

ADAPTIVE CRUISE CONTROL SYSTEM Change gear automatically Function properly in poor weather condition Cannot pick up non-moving objects Effective in the speed between 30km-180km/h

BACKGROUND First laser-based system – Toyota’s Progress, a compact luxury sedan, in 1998 First radar-based system – Nissan’s Cima 41LV-2, a luxury sedan First American ACC model – Lexus’ LS 430, in 2000

FUNCTION Preset and maintain the car speed Measure the distance to the preceding car and the relative speed Adjust the car speed accordingly Maximum deceleration = 3.5m/s^2

ADVANTAGES Collision-avoidance system. 2.It is used for better fuel efficiency. 3.Improving comfort by allowing positioning changes more safely. 4.Traffic flow characteristics. 5.Its useful for long drives. 6.Reduces driver fatigue.

DISADVANTAGES The lack of need to maintain constant pedal pressure, which can help lead to accidents caused by highway hypnosis or incapacitated drivers. When used during inclement weather or while driving on wet or snow- and/or ice-covered roads, the vehicle could go into a skid. Stepping on the brake — such as to disengage the cruise control — often results in the driver losing control of the vehicle. The inefficiencies from cruise control can be even greater relative to skilled driving in hybrid vehicles.

APPLICATIONS Full cruise control (able to bring the car to a complete stop): BMW 7 Series, 5 series, 6 series Active Cruise Control with "Stop & Go" option, 2007+ models. (radar) Mercedes-Benz Models equipped with "Distronic Plus" ACC with "Presafe Brake" option. (radar) Volkswagen Passat, Touareg, 2011+ models. (radar) Volvo S60 equipped with "Technology Package" (Adaptive Cruise Control (ACC) with Queue Assist and Distance Alert), 2011+ models. (radar) Audi A8, Audi A7 and Audi A6 equipped with "Adaptive Cruise Control with Stop and Go function", 2011+ models (radar) 2010 Porsche Panamera, 2011 Porsche Cayenne  

CONCLUSION This seminar has described about the cruise control systems that are commonly seen in luxury cars now a day. Fully autonomous car is probably not viable in the foreseen future. Then nearby vehicles would be in constant communication with each other and act co-operatively, enabling groups of cars to race along like train cars, almost bumper to bumper, at speeds above 100 km/hr. It will probably take decades, but car accidents may eventually become almost as rare as plane crashes are now. The automobile, which transformed the developed world by offering mobility and autonomy, will finally stop exacting such an enormous cost in human lives.   

REFERNCES 1. www.google.com 2. www.howstuffworks.com 3. www.wikipedia.com 4. www.google.com/images 5. Automobile Engineering by Kevin A. Lee.

THANK YOU