VISVESVARAYA TECHNOLOGICAL UNIVERSITY KARNATAKA,INDIA SEMINAR TITLE DRIVE-BY-WIRE TECHNOLOGY SUBMITTED BY MOHIT MAHESHWARI USN-1BJ07EC050 SRI BHAGAWAN MAHAVEER JAIN COLLEGE ENGINEERING

CONTENTS INTRODUCTION EVOLUTION OF SAFETY TECHNOLOGY FLY-BY-WIRE TECHNOLOGY DRIVE-BY-WIRE TECHNOLOGY ELECTRONIC THROTTLE CONTROL ANTI-LOCK BRAKING SYSTEM THE FUTURE REFERENCES

INTRODUCTION Automobiles are the major lifeline by which people travel. In the U.S the number of vehicles has increased from just 4,192 units in 1900’s to more than 204 million units in 2000’s. With the increase traffic the number of accidents are also increasing drastically. Car manufacturers world wide are vying with each other to invent more reliable gadgets there by coming closer to the dream of the ‘Advanced safety vehicle’ or ‘Ultimate safety vehicle’.

EVOLUTION OF SAFETY TECHNOLOGY IN CARS

FLY-BY-WIRE TECHNOLOGY In modern aircrafts hydraulic and mechanical transmission components are more and more replaced by electronic components. The movements of flight controls are converted to electronic signals transmitted by wires hence the term fly-by-wire was coined.

DRIVE-BY-WIRE TECHNOLOGY Drive-by-wire technology also known simply as “X-by-wire” technology replaces the direct mechanical linkages between the driver and the various car elements with electronic components. A car with this type of system mainly employs electronics to control wide range of vehicle operations including steering , braking , acceleration etc. Although the mechanical systems are powerful they can become overly complex , inefficient and conductive to wear and tear over the years.

DIFFERENT DRIVE-BY-WIRE SYSTEMS

IC ENGINES AND THROTTLE ASSEMBLY In internal combustion engines, the throttle is a valve that directly regulates the amount of air entering the engine, indirectly controlling the fuel burnt on each cycle and maintaining constant air/fuel ratio. The throttle body is located between the air filter box and the intake manifold. In convectional throttle system, the valve is mechanically linked with the throttle pedal or lever. In electronic throttle control the valve is electronically controlled that allows the electronic control unit to reduce the emissions.

LOCATION OF THROTTLE BODY IN AN IC ENGINE

ELECTRONIC THROTTLE CONTROL Electronic throttle control are also known as throttle-by-wire systems. Basic components of throttle-by-wire systems are A position sensor on the accelerator pedal that determines the driver requirements. An electronically controlled throttle body with a small electric motor to open/close the throttle. An electronic control unit determines and positions the air valve the appropriate position through the use of a motor.

WORKING OF ELECTRONIC THROTTLE CONTROL

BLOCK DIAGRAM OF ELECTRONIC THROTTLE CONTROL

ELECTRONIC THROTTLE CONTROL COMPONENTS

1.ACCELERATOR PEDAL MODULE A potentiometer registers the exact position of accelerator module. A high degree of precision is guaranteed.

2.ELECTRONIC CONTROL UNIT In automotive electronics, electronic control unit (ECU) is a generic term for any embedded system that controls one or more systems in a motor vehicle. Electronic control unit controls the cylindrical charge, fuel ignition, ignition timing and the idle speed control system.

3.THROTTLE POSITION SENSOR Throttle position sensor is a feedback device that informs the ECU about the rate of throttle opening and relative throttle position TPS is a variable resistor that changes resistance as the throttle opens and signals the ECU which then richens the fuel mixture to maintain proper air/fuel mixture.

ANTI-LOCK BRAKING SYSTEMS Antilock braking systems ABS are electronic systems that monitor and control wheel slip during vehicle braking. ABS can improve vehicle control during braking, and reduce stopping distances on slippery road surfaces by limiting wheel slip and minimizing lockup. Rolling wheels have much more traction than locked wheels. Reducing wheel slip improves vehicle stability and control during braking, since stability increases as wheel slip decreases.

WORKING OF ABS  Brake caliper (1) and wheel speed sensor (2) 

ABS OPERATION Wheel speed sensor constantly monitors and sends electronic pulses to the ECU at a rate proportional to wheel speed. During rapid deceleration ,the ECU signals the modulator valves to reduce brake pressure to the wheels to avoid locking of wheels. The ECU acts to modulate the brake pressure to achieve maximum braking without wheel lock-up. ABS can modulate the pressure on the brake as high as 18 times per second.

ABS V/S NO ABS In the diagram above, the driver hits the brakes hard on a slippery surface (1), then steers (2), and successfully manages to avoid the obstacle. ABS prevents the wheels from locking, and this allows you steer. Without ABS, as the driver applies the brakes the wheels lock (1). Despite applying the brakes ,the car continues straight ahead due to the loss of steering control (2) and a collision results.

BENEFITS OF ABS ABS reduces braking distances on dry and slippery roads. ABS adjusts the brake pressure much faster and more accurately than car drivers as electronic components are perform faster operation. Increases steering ability and vehicle stability when braking. If the electrical/electronic system fails, the ABS is shut off, returning the vehicle to normal braking.

EFFECTIVENESS OF ABS DISADVANTAGES OF ABS Reduced the risk of multiple vehicle crashes by 18 percent. Reduced the risk of run off-road crashes by 35 percent. DISADVANTAGES OF ABS It is costly. Maintenance of a car equipped with ABS is very costly.

THE FUTURE Drive-by-wire technology might allow a car to become completely separate from its controls, meaning that a car of the future might theoretically be controlled by any number of different control systems: push buttons, joysticks, steering wheels, or even voice commands.

CONCLUSION Drive-by-wire technology will change the way people drive. The technology will increase fuel economy and will reduce engine emissions. The main question is that is this technology safe? The sensors on a brake-by-wire system could make an error in calculation, causing an accident. As the fly-by-wire technology has become a success, it’s likely that experience and product testing could bring more drive-by-wire systems safely to everyday cars.

REFERENCES www.howstuffworks.com www.youtube.com www.wikipedia.org Bosch automotive handbook ,SAS ,ISBN:978-0-7680-1953-3 Robert D Garrick , Delphi technologies Inc.

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