SENSORS IN AUTOMOBILES

By

Branch AEIE

Purushottam Institute Of Engg. And Tech.

WHAT IS A SENSOR ?

A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube. A thermocouple converts temperature to an output voltage which can be read by a voltmeter.

AUTOMOBILES CONTAIN HUNDREDS OF SENSORS!

anti-lock brakes seatbelts automatic locks

gas gauge airbags oxygen sensors

air conditioner heater temperature sensor

car alarm speedometer oil pressure

VEHICLE NAVIGATION SYSTEM

Cooperation of wireless sensors (e.g. GPS + Accelerometer + Camera

SMART CAR : SPECIAL FEATURES

1. There are so many people killed in the car accidents that car accident reports can be found in newspaper nearly every day.

2. A smart car can alert the driver if he becomes drowsy.

3. The computer in the car will totally eliminate the cases of getting lost and getting stuck in traffic.

4. The computer in the car sends out a radio signal that can be detected by a satellite.

5. By establishing the relation between the rotation in the steering wheel and the car’s position on a map, the computer can tell us where the car is.

At the heart of each automobile is the engine

Modern engines use software loaded in the engine’s Engine Control Module (ECM) to optimize performance and efficiency

OVERVIEW OF THE MITSUBISHI 4G93 ENGINE

The sensors connected to the ECM are:

… air flow sensor

… air intake temperature sensor

… intake-manifold vacuum or manifold absolute pressure (MAP) sensor

… engine coolant temperature sensor

… throttle position sensor

… oxygen sensor

… Hall effect crankshaft sensor

… Hall effect camshaft sensor

MITSUBISHI ENGINE SENSORS

Throttle Position Sensor

… rotary type sensor – wiper blade and resistance coil form a simple voltage divider

… controls the idle speed of the engine

The Oxygen Sensor

… measures amount of oxygen that is left after combustion

… air-fuel ratio is correct when the oxygen sensor reads 0.45V

The Hall Effect Crank Sensor

… calculate the speed of the engine

… calculate the position of each cylinder

The Hall Effect Camshaft Sensor

… calculate the position of each cylinder

… firing must occur a few degrees before Top Dead Center (TDC)

WSNS - APPLICATIONS: AUTOMOBILE

º Intra-vehicle:

: Objective: remove excessive wires

: Monitoring difficult access areas

: Easy access to useful information

Inter-vehicle:

: Objective: improve driving safety

Automobiles are the nodes themselves

Messages may be:

. Dangerous conditions

Traffic jams

“Smart” road signs

USE OF SENSORS IN RACING SCENARIO

º Provide to the driver:

: Tire pressure

: Lights failure

: Fuel consumption

: Acceleration

º Send to the pit:

: Heart rate and blood pressure

:Help requests

ACTIVE ELECTRICAL POWER STEERING, AUTOMATED PARKING,

ACTIVE STEERING Active electrical power steering

… The steering gear box is controlled by the electronics to achieve smoother, more accurate steering

Automated Parking

… BMW Park-Assist uses sensors to detect an empty parking and parallel-park the car

… Commonly-used sensor: Lidar (light detection and ranging technology) – laser-based range detection

Active Steering

… Superposition steering (BMW)

INTERSECTION ASSISTANT WITH CAR TO CAR COMMUNICATION

(USING WLAN)

Collisions at street intersections can be avoided with Intersection Assistant

Cornering and Intersection Assistant

… Radar and laser sensors enable the monitoring of surroundings of cars

… Obstacles are identified. Cars can be braked automatically

… Intersection Assistant can be realized with currently commercially available WLAN. Up to now, it is only used in driver assist mode.

STEERING SYSTEMS

Automated parking and disturbance control (e.g., from side wind) will be the next development steps

To realize the accident-free vehicle, more near-field information will be necessary

After so-called “collision avoidance,” automated driving can be realized

The next development steps will need to concentrate on “camera vision”

Content/ Information Providers

Traffic / Weather / TravelRoute Guidance /

Internet Access /E-MAIL / Car Diagnosis / Navigation

Extra Functions

Exclusive Line

Integrated ECU

GPS

Traffic Events / Weather / Travel

POI / Stocks / News

NAVI. ControlAccident Report

E-mailContents/Information

AV/NAVI

Hands Free

Wireless MODEM

TelecomCompany

AVICSCenter

DAB/Cellular

Data CollectingData Processing

Exclusive Line

AVICS Center or Internet Sites Connection

AVICS (Advanced Vehicle Information & Communication System)

VIBRATION REDUCTION ON AUTOMOTIVE SHAFTS USING

PIEZOCERAMICS The use of intelligent

materials e.g. piezoelectric ceramics seems to be the most promisingly ones for the use in automobile structures.

Piezoelectric devices and active vibration reduction are advantageous in this application field due to their low mass to performance ratio.

Applied piezoceramics on a test automotive shaft

THANK YOU

Questions ?