Automotive Electrical System

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CHAPTER 4:AUTOMOTIVE

ELECTRICALSYSTEM

Starting System


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OverviewIn order to start the engine, it must frstbe

rotated at some speed or air-uel mixtureto enter the cylinders.

It is the purpose and unction o thestarting circuit to create the necessary

power by converting electrical energy romthe battery into mechanical energy at thestarter motor and rotate the engine.

starting system includes the battery,starter motor, solenoid, relay, starter drive,and ignition switch.


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Starting circuit


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1. The Starter mtr. The starter an electric

motor can provide high power at low speed tocran an engine. !raning speed re"uired or theengine to start is #$ to %&$ rpm.

!. The "attery. The battery must be o the correct

capacity and be at least #$% &harge' to providethe necessary current and voltage or correctoperation o the starter.

(. The Starter s)eni' r re)ay.Is ane)e&trmagneti&switch containing two separatebut connected electromagnetic windings. Thisswitch is used to engage the starter drive and tocontrol the current rom the battery to the startermotor.

tarting System Cm*nents
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Starting%20System.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Starting%20System.mp4


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4. The Starter drive. The starter drive uses a small gear that

contacts the engine flywheel gear and transmits starter motorpower to rotate the engine (min starting speed 100 RPM).

5. The Ignition switch The ignition switch and safety control

switches control the starter motor operation.

tarting System Cm*nents

An inhibitor (neutralsafety) switchis usedto prevent the vehiclefrom being startedwhile in gear.
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/starter%20drive.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/starter%20drive.mp4


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Types o switch system'

(ey-operated )ush Start *utton

+emote ehicle Start +S

(eyless /ntry Smart card

m*+ter,Cntr))e' S-it&h System


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CHAPTER $:AUTOMOTIVE

ELECTRICALSYSTEM

Charging System


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0ll vehicles operate electrical componentsby taing current rom the battery. It is thepurpose and unction o the charging tee* the battery /+))y &harge'and tosatisy the demands o the ignition andelectrical systems.

The charging system includes the

alternator, voltage regulator, the battery,and the indicator gauge or warning light onthe dashboard.

CHAR0I0 SYSTEM


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0s long as the engine is running, all o the

power or the accessories is delivered by thealternator. The battery is actually a load on thecharging system. The only time that the batterywould supply power with the engine running is

when the current capacity o the alternator isexceeded or when engine is at a very low idle


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1. The A)ternatr

.

0n a)ternatris an electrical generator thatconverts mechanical energy to electrical energyin the orm o alternating current.

. 0 battery cannot 2store3 alternating current4thereore, this alternating current is changed todirect current 5! by diodes inside thegenerator.

HAR0I0 SYSTEM COMPOETS
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/alternator%20components.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/alternator%20components.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/alternator%20components.mp4


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)ternatr -ring *rin&i*)es

A rotor inside a generator is turned by a belt and drive pulley

turned by the engine. The magnetic field of the rotor generatesa current in the windings of the stator by electromagnetic

induction.

6ield current 7owingthrough the slip ringsto the rotor createsalternating north 8south poles on therotor, with a magneticfeldbetween each fnger othe rotor.
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Alternator%20principles.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Alternator%20principles.mp4


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!. V)tage Reg+)atr

.

The voltage regulator controls the feld currentapplied to the alternator

. 9hen there is no current applied to the feld,there is no voltage produced rom the alternator.9hen voltage drops below1(.$ V the regulator

will apply current to the feld and the alternatorwill start charging.

. 9hen the voltage exceeds 14.$ Vthe regulatorwill stop supplying voltage and the alternator

will stop charging.. 5uring high engine speeds and low current

demands, the regulator will ad:ust the feldcurrent to lower the alternator output voltage.!onversely, when the vehicle is idling and the

current demands may be high, the regulator will
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Voltage%20regulator.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/Voltage%20regulator.mp4


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(. 2arning in'i&atr )ight r ammeter

. To alert the driver of a malfunction in the chargingsystem

. An ammeter also indicates the condition of thecharging system. A low battery will be indicated by a

high charging current (+). A wiring short or faultyaccessory will show as a high rate of discharge (-).


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4. A+tmti3e "attery

.

0n important component in the auto electricalsystem

. 0ll batteries used in modern automotiveapplications are o the lead-acid storage type.

/ssentially, a lead-acid storagebattery is an electro-chemicaldevice or storing energy inchemical orm.

This energy can be released as

electricity when connected to anoutside circuit. 0 battery canperorm this operationrepeatedly.


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+n&tins / "attery

To provide current or the starter and ignitionsystem when craning

To provide the extra power necessary when thevehicle;s electrical load radio, lights, etc

exceeds the supply rom the charging systemcurrent

To act as a voltage stabili


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"attery Cnstr+&tins:

1. P)ate gri's 5 Se*aratrs

two types o plates -- positive negative plates.The positive plates are grids lead-antimonyalloy pasted with active lead peroxide)bSO=.

>egative plates are grids pasted with a type o

lead sponge lead - )b. to prevent the plates rom touching short

circuit, thin sheets o non-conductive porousmaterial called separators are used. These areplaced between every positive and negative

plate


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"attery Cnstr+&tins:

Maintenance-Free versus Standard Battery Grids

A normal battery uses up to 5% antimony in the plate gridsto add strength. The more amount of antimony, the more

gassing (hydrogen and oxygen gases released), and the more

water the battery will use.

Maintenance-free batteries use calciuminstead of

antimony, because 0.2% calcium has the same strength as 6%

antimony.


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"attery Cm*nents:

E)e&tr)yte mixture o suluric acid ?%SO= %&@ and

water A&@ the strength or percentage o the suluric

acid in the solution is measured by its

specifc gravity, that is, the density o theelectrolyte versus the density o purewater

the specifc gravity or electrolyte strengtho a ully charged battery is in the range o

1.!67,1.!#$. This means that itselectrolyte is at least B.%#$ times heavierthan pure water


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H- "attery 2rs

The most important attribute o a

lead - acid storage battery is itschemical reversibility, i.e operatesin a constant process o chargeand discharge.

9hen a battery is connected to aload that needs electricity, such asthe starter in your car, current7ows rom the battery. The battery

begins to be discharged. In the reverse process, it becomes

charged when current 7ows bacinto it.
http://var/www/apps/conversion/tmp/Video/Discover%20How%20Car%20Batteries%20Work.mp4http://var/www/apps/conversion/tmp/Video/Discover%20How%20Car%20Batteries%20Work.mp4


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H- "attery 2rs

During Discharging The positive-plate lead dioxide (PbO2)

combines with the SO4from the electrolyte and releases itsO

2into the electrolyte, forming H

2O. The negative plate also

combines with the SO4from the electrolyte and becomes lead

sulfate(PbSO4).


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H- "attery 2rs

During Charging The sulfate ion (acid) leaves both the

positive and the negative plates and returns to theelectrolyte, where it becomes normal-strength sulfuricacid solution. The positive plate returns to lead dioxide(PbO

2) and the negative plate is again pure lead (Pb).


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Open circuite voltage or variouscharges

The open circuit voltage , is measured when the engineis off and no loads are connected. It can be

approximately related to the charge of the battery


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CHAPTER $:AUTOMOTIVE

ELECTRICALSYSTEM

Ignitin System


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Ignitin System

The ignition system provide high intensity

spar to the spar plug to ignite air-uelmixture in the combustion chamber.

The spar must be supplied at the right timeand it must has suCcient energy over a range

o condition to ignition the air-uel charges. Ignition system consist o '

*attery Dow tension cable Ignition !oil 5istributor ?igh tension cable Spar plugs cable Spar plugs
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/ignition%20coil.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/distributor.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/spark%20plug.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/spark%20plug.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/distributor.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/ignition%20coil.mp4


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Ignitin System

The energy or ignition come rom battery 8alternator

The voltage is increase by ignition coil. The system has % curcuits'

o The )rimary Dow Tension !ircuit E toinitiate the spars

o The Secondary ?igh tension !ircuit Eto produces high voltage and distributeto the spar plugs.

There are F general types o ignition systems'

1. "rea IgnitinE uses contact breaerpoint in distributor to initiate the spar.!. E)e&trni& ignitin E the switching or

triggering o the primary circuit iscarried out electronically.

(. 8ire&t Ignitin E has no distributor
http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/contact%20breaker%20ignition.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/electronic%20ignition.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/distributorless%20ignition.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/distributorless%20ignition.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/electronic%20ignition.mp4http://var/www/apps/conversion/tmp/Video/ISC%205_Electrical%20System/contact%20breaker%20ignition.mp4

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