engine auxilary system

8/16/2019 Engine auxilary system

1/16

UNIT-III

ENGINE AUXILIARY SYSTEMS

FUEL FEED SYSTEM

REQUIREMENT OF AN IDEAL PETROL ENGINE FUEL:

Generally gasoline is used as a uel in !os" o "#e $e"rol engine %S& I& engine'& I" is a !i("ure o

!any reinery $rodu)"s )on"aining $arain*s+ a$o"#e!s and aro!a"i)s in dieren" ra"ios& T#e ra"io

de$ends u$on "#e desired ,uali"y o "#e uel& T#e i!$or"an" ,uali"ies o "#is uel are as gi-en under&

.& An"i/no)/ ,uali"y

0& 1ola"ili"y

2& Gu! de$osi"s

3& S)ul$"ure )on"en"

1. ANTINO45 QUALITY:

So!e"i!es "#e las" $ar" o "#e )o!$ressed air uel !i("ure e($lodes "#ere6y $rodu)ing a sudden and

s#ar$ $ressure in)rease "#e /no)/ing noise and $rodu)es a #ard #a!!er 6lo7 on "#e $is"on& T#ereore

gasoline $rodu)es al7ays "end "o !ini!i8e "#e /no)/ing "enden)ies o uel&

0& 1OLATILITY:

T#e ,uali"y 7i"# 7#i)# a li,uid -a$ori8es easily is )alled -ola"ili"y& 9#en a li,uid -a$ori8es a" rela"i-ely lo7

"e!$era"ure "#en i" is )alled #ig# -ola"ile& I i" -a$ori8es a" a #ig#er "e!$era"ure i"s -ola"ili"y is lo7& T#e !os"

i!$or"an" as$e)"s o -ola"ili"y are as gi-en under:

a' Easy s"ar"ing

6' Freedo! ro! -a$our lo)/

)' Qui)/ 7ar!ing

d' S!oo"# a))elera"ion

e' Good e)ono!y

' Freedo! ro! )ran/ )ase dilu"ion

g' T#e -ola"ili"y 6lend&


2/16

2& GUM DEPOSITS:

So!e"i!es unsa"ura"ed #ydro)ar6ons 6lended in "#e gasoline 7#i)# o(idi8e during s"orage and or! a

$rodu)" /no7n as gu!& T#e gu! is undesira6le in "#e uel& e)ause i" de$osi"s in )ar6ure"or+ on in"a/e -al-es

$is"on rings and o"#er $ar"s o "#e engine "#ere6y res"ri)"ing "#e regular su$$ly o "#e uel& T#ereore+ a good uel

!us" 6e o su)# a ,uali"y "#a" nei"#er i" as gu! )on"en" nor or! gu! during s"orage&

3& SULP;UR 4ONTENT:

I" is an undesira6le )on"en" in "#e gasoline& e)ause i" "ends "o or! )orrosi-e )o!$ound 7#i)# a""a)/s

-arious $ar"s and "#ere6y in


3/16

iii' I" $ro-ides and )on"rols "#e a!oun" and s"reng"# o air>uel !i("ure under -arying )ondi"ions o

load and s$eed o "#e engine&

i-' I" $ro-ides easy s"ar"ing 7i"# "#e engine in )old

-' I" ensures "#e engine "o run slo7ly 7i"#ou" !issing and 7i"#ou" undue 7as"age o uel+

-i' I" $ro-ides !a(i!u! a))elera"ion 7i"#ou" #esi"a"ion "o $i)/ u$ s$eed 7#en "#e "#ro""le is suddenly or

slo7ly o$ened&

0&3& 0& 4LASSIFI4ATION OF 4ARURETTOR:

.& A))ording "o "#e arrange!en" o loa" )#a!6er

%a' E))en"ri) %6' 4on)en"ri)

0& A))ording "o "#e dire)"ion air lo7

%a' Do7n dra" %6' Side dra" %)' U$ dra"

%d' Se!i>do7n dra"&

2& A))ording "o "#e nu!6er o uni"s

%a' Si!$le %6' Dual %)' Four@6arrel&

3& A))ording "o "#e "y$e o !e"ering sys"e!

%a' Air 6leed


4/16

0&& SIMPLE 4ARURETTOR:

A si!$le )ar6ure"or s#o7n in Fig& 03& 4onsis"s o "#e round )ylinder 7i"# )ons"ri)"ed se)"ion o a uel no88le+

a "#ro""le -al-e and e loa" )#a!6er& T#e round )ylinder* )alled air #orn and ?)ons"ri)"ed se)"ion is "#e -en"uri&

1en"uri and loa" )#a!6er are )onne)"ed 6y "#e uel no88le& T#e "#ro""le -al-e )an 6e "il"ed "o o$en or )lose "#e air

#orn& T#e )ons"ru)"ion and un)"ion o ea)# $ar" o "#e )ar6ure"or are as:

1ENTURI:

A -en"uri is a narro7 s$a)e in "#e )ylindri)al air #orn+ "#roug# 7#i)# "#e air $asses& As "#e sa!e a!oun" o

air !us" $ass "#roug# e-ery $oin" in "#e air #orn+ i"s -elo)i"y 7ill 6e "#e grea"es" a" "#e narro7es" $oin"& T#e !ore

"#is area is redu)ed+ "#e grea"er 7ill 6e "#e -elo)i"y o air& T#e o$ening o "#e dis)#arge


5/16

T;ROTTLE 1AL1E:

T#e "#ro""le -al-e is a )ir)ular dis) i" is lo)a"ed in "#e !i(ing )#a!6er o "#e air #orn& I" )an 6e "il"ed

To $ro$or"ions o air uel !i("ure a" dieren" s$eeds& Dieren" !e"#ods or $ro-iding )o!$ensa"ion are

%.' Air -al-e regula"ion

%0' 4o!$ensa"ing

"ed "#en due "o su)"ion "#e no88le "i$ su$$lies a sui)ien" ,uan"i"y o uel "o s"ar" i"& As "#e engine s$eed is

in)reased !ore su)"ion is de-elo$ed ~t "#e no88le "#us no88le "i$ 6e)o!es e!$"y "#us allo7ing "#e air run "#roug#

"#e #oles o and air 6leed #oles in"o "#e


6/16

de)reases "#e lo7 o "#e uel& In "#is 7ay 7i"# "#e #el$ o air 6leed )o!$ensa"ion a desired ,uan"i"y o uel is

su$$lied 6y "#e no88le or a dieren" s$eed o "#e engine&

B& 0& 1ARIALE ET OR 4OMPENSATING ET

In a )ar6ure"or in addi"ion "o !ain no88le+ 7#en an e("ra uel su$$ly no88le res"ri)"ed 6y an orii)e is

$ro-ided+ "#en "#is )ir)ui" o uel is /no7n as )o!$ensa"ing


7/16


8/16

0& DIESEL FUEL FEED SYSTEM:

T#e diesel uel eed sys"e! ensures "#a" "#e diesel oil is in


9/16

ea)# dro$le" in"o )on"a)" 7i"# a sui)ien" o(ygen "o gi-e ,ui)/ and )o!$le"e )o!6us"ion&

FIG&0&. s#o7s a uel in


10/16

NU

T

CAPMiT

SPtN

OLE>

HOL

DER

INLET AOAPTOR

FIG&0&. Fuel In


11/16

No88le is a""a)#ed "o "#e 6ody o "#e in;OLE:


12/16

PINTLE NOHHLE

T#ese no88les #a-e !any #oles arran" around "#e no88le in a )ir)le& T#e nu!6er+ si8e+ and

angle o "#e #oles !ay -ary a))ording "o "#e engine&

T#e Na8is FG&0&.) $ro-ides a so" or! o s$ray o$era"ing a" a lo7 in. 5NJS,& !e"& T#is sel )learing no88le #a-ing a s!all )one e("ension a" "#e

end o "#e needle $rodu)es a )oni)al s$ray $a""ern& As i" lea-es "#e in


13/16

A" s"ar"ing "#e no88le -al-e is li"ed slig#"ly "#us "#e $es"le #ole is no" )leared and "#e uel is

only dis)#arged "#roug# "#e au(iliary #ole in"o "#e )en"ral #o" 8one "#ere 6y o6"aining 6e""er )old

s"ar"ing $eror!an)e& 9#en engine rea)#es "o i"s nor!al s$eed "#en "#e needle -al-e is li"ed

ro! "#e $es"le #ole o "#e no88le "o $ass "#e uel "#roug# "#e lin"el #ole and en"ering "#e )#a!6er

"angen"ially& In "#is 7ay "#is "y$e o no88le $ro-ides 6o"# "#e ad-an"age o )old s"ar"ing as 7ell as

o nor!al runnin o "#e engine&

FUEL INE4TION PUMP

PLUNGER TYPE:

T#e $ur$ose o "#e in


14/16

$u!$ )onsis"s o a -er"i)al )#annel e("ending ro! i" u$$er edge "o an annular groo-e+ "#e "o$

edge o 7#i)# is )u" in "#e or! o a #eli( as s#o7n in "#e igure& 0&0a

In re)en" designs a $lunger )onsis"s o a )en"ral #ole ins"ead o "#e )#annel and a

#eli)al groo-e ins"ead o #eli( and annular groo-e& T#e lug or lo7er $ar" o "#e $lunger is

engaged in "#e slo" o "#e "oo"#ed slee-e& T#e ro"ary !o-e!en" o "#e "oo"#ed slee-e 7i"#

"#e $lunger is )on& Trolled 6y !eans o sliding !o-e!en" o "#e "oo"#ed ra)/+& A s$ring

loaded deli-ery -al-e is i""ed on i"s sea"ing $ro-ided a" "#e "o$ o "#e $u!$ 6arrel&

Reerring "#e ig& 0&0&6 "#e or)e o "#e -al-e s$ring al7ays $resses "#e deli-ery -al-e on

i"s sea"& T#e deli-ery -al-e is guided "#roug# i"s s"e! in "#e -al-e #older&

I" a)"s as a one 7ay -al-e and during "#e uel deli-ery s"ro/e i" is li"ed ro! i"s sea" so

"#a" "#e uel )an lo7 along "#e longi"udinal groo-es and o-er "#e -al-e a)e in"o "#e

deli-ery $i$es

OPERATION:

For "#e 7or/ing $rin)i$le o "#e $u!$+ say "#e $lunger is a" 6o""o! dead )en"re s"ar"ing

$osi"ion Under "#is $osi"ion "#e "7o uel inle" $or"s are un)o-ered ro! "#e sides o "#e $lunger

"#ey 6y allo7ing "#e uel "o en"er "#e 6arrel under eed $u!$ $ressure& As "#e $lunger !o-es

u$7ards "#e edge o i" )u"s>o "#e uel su$$ly& No7 "#e s$a)e a6o-e "#e $lunger is ull o uel&

Fur"#er u$7ard !o-e!en" o $lunger "ends "o li" "#e deli-ery -al-e agains" "#e $ressure o i"s

s$ring and #en)e en"ering "#e uel "#roug# "#e $i$e "o "#e in


15/16

)o!!uni)a"ing "#e uel a6o-e "#e $lunger "o "#e gallery+ -ia "#e -er"i)al slo" and "#an )u""ing>o

uel deli-ery "o "#e in


16/16

dis)onne)"ing i" au"o!a"i)ally 7#en "#e en"7ine #as s"ar"ed running& For "#is $ur$ose a se" o

gears or a ri)"ion dri-e su)# as a gear: edu)a"ion sys"e! is generally used "o engage en

engine auxilary system

Documents