Automotive electronics Systems by Ch.Ravikumar

Automotive ElectronicSystems

By CH.RAVIKUMART.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 skillsincreasing 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 ElectronicsPhase 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 ElectronicsPhase 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 entertainmente.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 ElectronicsPhase 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 entertainmente.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 ElectronicsPhase 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

Interior Light SystemAuto toll Payment

Rain sensor

Dashboard controller

Automated Cruise Control

Light failure controlInformation Navigation

EntertainmentHead 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 transponderDoor module

Keyless entry

Central locking

Throttle controlValve Control

E-gas

Suspension control

LED brake light

CompassStability 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 automobile’s networksBuses 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 NetworksD2B (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 firms—including Audi, BMW, Daimler-Chrysler, Becker Automotive, and Oasis Silicon Systems—developed 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 kbit/s) : LIN, CANClass B (50-500 kbit/s) : CAN, J1850MMedia (> 20 Mbit/s) : MOST, FirewireWireless : GSM, BluetoothSafety : Byteflight, TTP/C, Flexray

Future Needs for Networking

EnvironmentDetectionSystems

Telematics

Driver Interface

Powertrain

Steering Systems

Braking Systems

Rapidly Increasing Numberof Future Automotive Functions

Interconnections in the Vehicle

Multimedia

ConsumerInterface

Infotainment-Control

Powertrain andVehicle Dynamics

BodyElectronics

Sub-Bus

X-by-wire

Safety Bus

Safety/Reliability

Data Rate

Functional Applications

FlexRay

CAN

LIN

MOST

Close-loop Control Systems

Telematics Applications

Req

uire

men

ts 1 Mbits/s

20 Kbits/s

Strategic Technical Considerations

AUTOMOTIVE SENSORS

Oil sensor

Oxygen sensor

Fuel level

Accelerometer

Seat belt tensionPassenger Occupancy

Wheel speed

Tire pressure monitor

Anti thief sensorsRadar sensor

Rain sensor

Parking sensor

Indoor/outdoor temperature sensors

GPS

Water coolant temperature

Tachometer

SpeedometerOdometer

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 →Amplifier→CPU→wipers on, windows up

Rain sensor

Offset amplification raise the sensitivity of the sensor: night driving, high speed

Tire pressure monitorRF 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

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