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Automotive electronics Systems by Ch.Ravikumar

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The Presentation mainly concentrates in automotive electronics, sensors, and various In-Vehicle Networks

Text of Automotive electronics Systems by Ch.Ravikumar

  • Automotive Electronic Systems By CH.RAVIKUMAR T.E.(EXTC) WIT
  • Disciplines in Automotive Engineer Safety Engineering Fuel Economy/Emissions Vehicle Dynamics Vehicle Electronics Performance Shift Quality Durability / Corrosion engineering Package / Ergonomics Engineering etc
  • Safety Engineering Assessment of various crash scenarios and their impact on the vehicle occupants Requirements Include: Seat belt and air bag functionality Front and side impact testing Full vehicle crashes Assessments are done with various methods and tools: Computer crash simulation Crash test dummies
  • Fuel Economy/Emissions It is the measured fuel efficiency of the vehicle in miles per gallon or litres per 100 kilometers. Emissions testing the measurement of the vehicles emissions: hydrocarbons nitrogen oxides (NOx) carbon monoxide (CO) carbon dioxide (CO2), and evaporative emissions
  • Vehicle Dynamics It is the vehicle's response of the following attributes: ride, handling, steering, braking, comfort and traction Design of the chassis systems: suspension, steering, braking, structure (frame), wheels and tires, and traction control Dynamics engineer to deliver the Vehicle Dynamics qualities desired
  • Automotive electronics is an increasingly important aspect of automotive engineering Responsible for operational controls throttle, brake and steering controls comfort and convenience systems infotainment and lighting systems It would not be possible for automobiles to meet modern safety and fuel economy requirements without electronic controls Vehicle Electronics
  • Performance is a measurable and testable value of a vehicles ability to perform in various conditions how quickly a car can accelerate (e.g. standing start 1/4 mile elapsed time, (0- 60 mph, etc.) Generate without losing grip, recorded lap times, cornering speed, brake fade, etc Performance can also reflect the amount of control in inclement weather (snow, ice, rain) Performance
  • Trends in automotive > 1920 + pneumatic systems low high technical skills + hydraulic systems low driving skills > 1950 + electric systems increasing good technical skills increasing driving skills > 1980 + electronic systems congestion low technical skills + optronic systems starts high driving skills > 2010 + nanoelectronics congested very low technical skills + biotronic systems optimization decreasing driving skills starts > 2040 + robotics maximal and no technical skills + nanotechnology optimized no driving skills CAR Technology TRAFFIC DRIVER SKILLS > 1891 mechanical system very low very high technical skills
  • Automotive Electronics Phase 1: Introduction of Electronics in non-critical applications Driver information and entertainment e.g. radio, Comfort and convenience e.g. electric windows, wiper/washer, seat heating, central locking, interior light control Low intelligence electronic systems Minor communication between systems (pushbutton control) No impact on engine performance No impact on driving & driver skills
  • Automotive Electronics Phase 2: Electronics support critical applications Engine optimization: e.g. efficiency improvement & pollution control Active and Passive Safety e.g. ABS, ESP, airbags, tire pressure, Xenon lamps Driver information and entertainment e.g. radio-CD-GPS, parking radar, service warnings Comfort, convenience and security: e.g. airco, cruise control, keyless entry, transponders Increasingly complex and intelligent electronic systems Communication between electronic systems within the car Full control of engine performance No control of driving & driver skills But reactive correction of driver errors. Electronics impact remains within the car
  • Automotive Electronics Phase 3: Electronics control critical applications Full Engine control e.g. start/stop cycles, hybrid vehicles Active and Passive Safety e.g. X by wire, anti-collision radar, dead-angle radar Driver information and entertainment e.g. traffic congestion warning, weather and road conditions Comfort and convenience Very intelligent and robust electronics Communication between internal and external systems Information exchange with traffic network Full control of engine performance Control of driving and (decreasing) driving skills Proactive prevention of dangerous situations inside and around the car Full control of car and immediate surroundings
  • Automotive Electronics Phase 4: Fully Automatic Driver (1st generation) Traffic network takes control of the macro movements (upper layers) of the car Automatic Driver executes control of the car and immediate surroundings (lower and physical layers) ADAM : Automatic Driver for Auto-Mobile or EVA : Elegant Vehicle Automat Driver has become the Passenger for the complete or at least for most of the journey Driver might still be necessary if ADAM becomes an Anarchistic Driver And Madman or EVA becomes an Enraged Vehicle Anarchist
  • InteriorLight System Auto toll Payment Rain sensor Dashboard controller Automated Cruise Control Light failure control Information Navigation Entertainment Head Up Display Engine: Injection control Injection monitor Oil Level Sensing Air Flow Headlight: Position control Power control Failure detection Brake Pressure Airbag Sensing &Control Seat control: Position/Heating Key transponder Doormodule Keyless entry Central locking Throttle control Valve Control E-gas Suspension control LEDbrake light Compass Stability Sensing Power Window Sensor Backup Sensing Gearbox: Position control Where do we find electronics in a car
  • Emerging In-Vehicle Networks
  • Introduction In-vehicle networks Connect the vehicle's electronic equipments Facilitate the sharing of information and resources among the distributed applications These control and communications networks are based on serial protocols, replacing wire harnesses with in-vehicle networks Change the point-to-point wiring of centralized ECUs to the in-vehicle networking of distributed ECUs
  • Introduction Aims of In-Vehicle Network Open Standard Ease to Use Cost Reduction Improved Quality
  • Benefits of In-Vehicle Network More reliable cars More functionality at lower price Standardization of interfaces and components Faster introduction of new technologies Functional Extendibility Introduction
  • Decreasing wiring harness weight and complexity Electronic Control Units are shrinking and are directly applied to actuators and sensors Introduction
  • modern automobiles networks Buses Speed Origin D2B(5Mbit/s, electrical or optical mainly for digital audio) High Auto MOST(22.5Mbit/s, audio, video,control) High Auto FlexRay(10Mbit/s, x-by-wire, safety-critical control) High Auto Byteflight(10Mbit/s, constant latencies, airbag, sear-belt) High Auto TTP(5~25Mbit/s, real-time distributed/fault-tolerant apps) High Auto Bluetooth(10Mbits/s, wireless for infotainment equipments) High Consumer CAN(50-1000kbit/s control only) Low Auto J1850(10.4kbit/s and 41.6kbit/s, control) Low Auto LIN(20kbps, control) Low Auto Introduction
  • Overview of In-Vehicle Networks D2B (Domestic Data Bus ) Matsushita and Philips jointly developed Has promoted since 1992 D2B was designed for audio-video communications, computer peripherals, and automotive media applications The Mercedes-Benz S-class vehicle uses the D2B optical bus to network the car radio, autopilot and CD systems The Tele-Aid connection, cellular phone, and Linguatronic voice-recognition application
  • Media-Oriented Systems Transport (MOST) It was initiated in 1997 Supports both time-triggered and event-triggered traffic with predictable frame transmission at speeds of 25Mbps Using plastic optic fiber as communication medium Overview of In-Vehicle Networks
  • The interconnection of telematics and infotainment such as video displays, GPS navigation systems, active speaker and digital radio More than 50 firmsincluding Audi, BMW, Daimler-Chrysler, Becker Automotive, and Oasis Silicon Systemsdeveloped the protocol under the MOST Cooperative Overview of In-Vehicle Networks
  • Time-triggered protocol (TTP) It was released in 1998 It is a pure time-triggered TDMA protocol Frames are sent at speeds of 5-25Mbps depending on the physical medium Designed for real-time distributed systems that are hard and fault tolerant It is going on to reach speeds of 1Gbps using an Ethernet based star architecture Overview of In-Vehicle Networks
  • FlexRay FlexRay is a fault-tolerant protocol designed for high-data-rate, advanced-control applications, such as X-by-wire systems (high-speed safety- critical automotive systems) Provides both time-triggered and event-triggered message transmission Messages are sent at 10Mbps Overview of In-Vehicle Networks
  • Both electrical and optical solutions are adopted for the physical layer The ECUs are interconnected using either a passive bus topology or an active star topology FlexRay complements CAN and LIN being suitable for both powertrain systems and XBW systems Overview of In-Vehicle Networks
  • Byteflight Developed from 1996 by BMW A flexible time-division multiple access (TDMA) protocol using a star topology for safety-related applications Messages are sent in frames at 10Mbps support for event-triggered message transmission Overview of In-Vehicle Networks
  • Guarantees deterministic (constant) latencies for a bounded number of high priority real-time message The physical medium used is plastic optical fiber Byteflight can be used with devices such as air bags and sear-belt tensioners Byteflight is a very high performance network with many of the features necessary for X-by-wire Overview of In-Vehicle Networks
  • Bluetooth An open specification for an inexpensive, short- range (10-100 meters), low power, miniature radio network. Easy and instantaneous connections between Bluetooth-enabled devices without the need for cables vehicular uses for Bluetooth include hands-free phone sets; portable DVD, CD, and MP3 drives; diagnostic equipment; and handheld computers Overview of In-Vehicle Networks
  • Controller area network (CAN) Was initiated in 1981 and developed by Bosch developed the controller Message frames are transmitted in an event- triggered fashion Up to 1Mbps transmission speed It is a robust, cost-effective general control network, but certain niche applications demand more specialized control networks. Overview of In-Vehicle Networks
  • Local interconnect network (LIN) A master-slave, time-triggered protocol As a low-speed (20kbps), single-wire LIN is meant to link to relatively higher-speed networks like CAN LIN reveals the security of serial networks in cars Overview of In-Vehicle Networks
  • network is used in on-off devices such as car seats, door locks, sunroofs, rain sensors, and door mirrors Overview of In-Vehicle Networks
  • Roadmap of in-vehicle networks optics bus
  • Protocol Comparison
  • Protocol Comparison Class A ( 20 Mbit/s) : MOST, Firewire Wireless : GSM, Bluetooth Safety : Byteflight, TTP/C, Flexray
  • Future Needs for Networking Environment Detection Systems Environment Detection Systems TelematicsTelematics Driver InterfaceDriver Interface PowertrainPowertrain Steering Systems Steering Systems Braking Systems Rapidly Increasing Number of Future Automotive Functions Rapidly Increasing Number of Future Automotive Functions
  • Interconnections in the Vehicle
  • Multimedia Consumer Interface Infotainment- Control Powertrain and Vehicle Dynamics Body Electronics Sub-Bus X-by-wire Safety Bus Safety/Reliability Data Rate Functional Applications
  • FlexRay CAN LIN MOST Close-loop Control Systems Telematics Applications Requirements 1 Mbits/s 20 Kbits/s Strategic Technical Considerations
  • Oil sensor Oxygen sensor Fuel level Accelerometer Seat belt tension Passenger Occupancy Wheel speed Tire pressure monitor Radar sensor Rain sensor Parking sensor Indoor/outdoor temperature sensors GPS Water coolant temperature Tachometer Speedometer Odometer
  • Engine Sensors Oxygen sensor Oil sensors Fuel gauge Dip - stick
  • High voltage: fuel mixture rich, little unburned oxigen Low voltage: fuel mixture lean, excess oxygen O2 sensors
  • Oil sensors On-board oil sensors and oil analyzers installed Oil pressure: Hydrostatic force per unit area Age of the oil in the engine: dielectric constant of the oil. Parallel plate capacitor separated by oil. An oil dielectric tester correlates to the acidity of the oil and indicates the level of oil degradation
  • Fuel gauge Inaccurate due to its mechanism, shape of fuel tank Gauge: resistance , current , bimetallic cools, straighten out, pull needle form full to empty. Newer car: resistor output into a microprocessor compensate shape of tank Damping needle movment up hill , down hill , turnFloat
  • Rotation sensors: Speedometer/Tachometer/Odometer
  • Sensors based on Hall Effect Speed Wheel speed Engine ignition timing Tahometer Odometer
  • Speedometer Transmission and driveshaft rotate permanent magnet rotate rotating magnetic field force act on speed cup electrical curretn flows (Eddy current) drag torque needle rotate same direction as magnetic field Transmission output rotate with a toothed metal disk at the end Stationary detector covers a magnetic coil Teeth move past the coil interrupt the magnetic field series of pulses sent to computer
  • Rain sensor Based on total internal reflection LED or Infrared light source Photodiode AmplifierCPUwipers on, windows up
  • Rain sensor Offset amplification raise the sensitivity of the sensor: night driving, high speed
  • Tire pressure monitor RF communication with on board computer
  • Car alarm system Simplest form, it is nothing but one or more sensors connected to some sort of siren Most modern car alarm systems: An array of sensors that can include switches, pressure sensors and motion detectors A siren, often able to create a variety of sounds so that you can pick a distinct sound for your car A radio receiver to allow wireless control from a key fob An auxiliary battery so that the alarm can operate even if the main battery gets disconnected A computer control unit that monitors everything and sounds the alarm -- the "brain" of the system
  • Door sensor In a closed-circuit system, the electric circuit is closed when the door is shut. This means that as long as the door is closed, electricity can flow from one end of the circuit to the other. But if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm. In an open-circuit system, opening the door closes the circuit, so electricity begins to flow. In this system, the alarm is triggered when the circuit is completed
  • Shock sensor
  • Tilt sensor
  • Pressure sensor Breaking glass has its own sound frequency Air pressure brief change as door open, windows break, even if the inside outside pressure is the same
  • Radar detectors and Jammers Detects radar/laser signals Try to disturb the reflected waves Emits jamming signals Warn the driver