Automotive electronics
Transcript of Automotive electronics
Automotive Electronics
Introduction
• Silicon content in automobiles has doubled in the last 10 years and will double again over the next five years !!!!
• Why Electronics in Automobiles ?
• Where in the Automobile ?
Electronics in present and future automobiles.
SAFETY & CONVENIENCE
BODY CONTROL POWER TRAIN DRIVER INFORMATION
Rear Window Defogger Cruise Control Ignition Digital Gauges
Climate Control Intermittent Wiper Spark Timing Digital Clock
Keyless Entry Antitheft Devices Voltage Regulator Audio Annunciator
Automatic Door Lock Electronic Suspension
Alternator Engine Diagnostic Results
Light Dimmer Electronic Steering Idle Speed control Service Reminders
Traction Control Multiplex Wiring Turbo Control Miles to Empty
Antiskid Braking Hard/Soft Ride Control
Emission System Shift Indicator
Window Control Communications Transmission Control
Head-up Display
Airbag Restraints Load Sensitive Braking
Diagnostics CRT Display
Cruise Control
• Keeps vehicle's speed constant.
• Prevents driver fatigue.
• Not suitable for all road conditions.
• Ambiguously classified as Non-Safety-Critical.
Features of Cruise Control
• Below the set speed, interlocking switches and control logic prevent the cruise control from being switched ON.
• Above the set speed, the choice to engage cruise control
rests with the driver. • Kicks out of action immediately a very modest touch of
braking is applied. • Not considered safe in heavy traffic, on bends, on wet or
icy roads etc.
Working of Cruise Control
SpeedEngine + Transmission
Vehicle speed sensor
Set SpeedSpeed error
-
+
Proportional to error signal
Throttle Actuator
Road Speed
Working continued…
Methods of Throttle actuation
1. Electro pneumatic servo valve actuation (engine vacuum used to provide the force via bellows).
2. Electronically controlled DC motor.
3. Stepper motor with electronic control.
Working continued…
Types of Electronic Control
1. Analogue + hard wired logic.
2. Digital, using a discrete cruise controller.
3. Digital cruise control function incorporated in the engine control module.
Challenges implementing Cruise Control
• A measure of protection against malfunction is taken by :
– reducing the supply voltage to the actuator or – Mechanically decoupling the actuator, by means of an
electromagnetic clutch.
• The above may not protect against an internal fault, rogue signal, leading to malfunction.
• High resistance in signal lines may lead to incorrect decoding of the states of Cruise Control switches.
• A wrongly decoded command signal or an internal fault may cause sudden acceleration.
TCS & ABS
• TCS: Traction Control System
• ABS: Anti-Braking System
• TCS and ABS are strongly complimentary systems.
• Both systems depend on accurate measurement of wheel speed, and share a single set of wheel speed sensors and many other control sensors.
GPS in Automobiles
• Orbiting 11,000 miles above the Earth, the 24 satellites are the heart of the system.
• They constantly broadcast signals that allow any ground receiver to calculate its distance from each satellite, based on the delay calculations of signal.
• Each satellite carries four atomic clocks--so accurate they lose only one second every 160,000 years.
• By capturing signals from at least three satellites, a GPS receiver can determine which point on the Earth is the exact distance from the satellites.
Applications of GPS in Automobiles
• Determine the shortest path to a particular destination.
• Getting to a known location in case someone gets lost.
• Avoiding the maximum number of tollbooths and determine the cheapest route.
• Prevent accidents by warning us against approaching vehicles, especially on deserted roads during the night-time.
• Provide entertainment by means of wireless radio and video links.
• Enable us to stay connected via a satellite phone, especially in areas where cellular networks do not exist.
Integration Technologies in Automobiles
• Bipolar technology was initially used in vehicles in the first analog systems.
• BiCMOS and/or CMOS are chosen to meet the highest performance and the highest levels of integration.
• Smart power ICs combine bipolar, CMOS and DMOS to provide higher power levels and integration of protection and performance features.
• Microprocessors cannot sense mechanical parameters, can only switch low current and are low voltage devices.
Semiconductor Technologies
Integration vs. Cost
Additional Integration at Risk
• Adding electronics to vehicles has created an on-board energy crisis.
• A transition from 14V to 42V system is expected.
Future Trends
Hands Free Parking
Steps involved in Parking Maneuver:
• Estimating Parking space.
• Pre-positioning of car.
• Executing the maneuver.
Hands Free Parking cont…
• One legal question is whether some countries would regard a car as not being under control if the driver’s hands were off the steering wheel.
Intelligent Headlamps
• Headlamps follow the steering wheel.
• Headlamps use GPS and follow the road.
• Pixel technology, based on Digital Micrometer Device (DMD).
Faster Processing
• Discrete Microprocessors add to cost and complexity.
• 32-bit processors can be included to do all tasks.
Conclusion