51656498 Motor Bakar Torak

8/20/2019 51656498 Motor Bakar Torak

1/70

PEMBEKALAN MATERI PRAKTIKUM

LAB KONVERSI ENERGIJurusan Teknik Mesin Fak Teknik UNSRI

MOTOR BAKAR TORAK

M Zachri Kadir


2/70

MOTOR BAKAR!"#$us%i"n En&ine'

INTERNAL

COMBUSTION

ENGINE

EXTERNAL

COMBUSTION

ENGINE

IGNITIONWORKING CYCLE

(STROKE)

SPARK IGNITION(MOTOR BENSIN/ OTTO)

COMPRESSION

IGNITION(MOTOR DIESEL)

4 STROKES

( 4 TAK )

2 STROKES

( 2 TAK )

TURBIN GAS

TURBIN UAP

MESIN UAP


3/70

E(%erna) !"#$us%i"n En&ineTur$in Gas


4/70

E(%erna) !"#$us%i"n En&ineTur$in Ua*


5/70

E(%erna) !"#$us%i"n En&ineMesin Ua*

STEAMFr"# BOILER


6/70

In%erna) !"#$us%i"n En&ineM"%"r Bakar T"rak


7/70

OTTO Engine ( Spark Ignition - 4 Strokes)


8/70

Diesel Engine !"#*ressi"n I&ni%i"n + , S%r"kes '


9/70

Four Stroke Engine

Intake Compression Power Exhaust

1. Intake Stroke piston moves from TDC to BDC,

drawing in fresh air-fuel mixture.

. Compression Stroke piston moves from BDC to

TDC, !ompress air-fuel mixture.

". #ower Stroke piston at TDC, spark plug ignite

the air-fuel mixture. the !om$ustion o!!ur

ver% fast that, in theor%, the piston still at

TDC. &fter that the piston is pushed to BDC.

'. (xhaust Stroke piston moves from BDC to TDC,

pushes the !om$ustion gases out.


10/70

Two Stroke Engine Power Compression Intake & Exhaust

1. Compression Stroke piston moves from

BDC to TDC, !ompress air-fuel

mixture.

. #ower Stroke piston at TDC, spark plug

ignite the air-fuel mixture. &fter the piston is pushed to BDC. )eanwhile,

a$out half wa%, !om$ustion gases are

dis!harged and fresh air-fuel mixture

is drawing in .


11/70

B"reS%r"ke

T-!

B-!

In%ake.a).e

E(haus%.a).e

Over Vie !" Reci*r"ca%in& En&inesTop Dead Center (TDC) * Upper most position

Bottom Dead Center (BDC) * Lower most position

Stroke * Length of piston travel

Bore * Diameter of the cylinder

Clearance Volume (Vc) * where piston is at !DC

Displacement Volume (Vd) :Swept Volume (V max -V min )

Compression Ratio (r v ) = (V max /V min ) = (V BDC /V TDC )

Mean Eecti!e "ressure (ME") :

" net # $%EP x $Displacement olume

Reci*r"ca%in& En&ine is INTERNAL COB!STION EN"INE / and is !)assi0iedin%" 1 %2*es3

#$ S%&r' I"ii!"3 Gas")ine En&ine/ Mi(in& air40ue) "u%side c2)inder/ i&ni%es $2a s*ark *)u&

2$ C!*%re++i!" I"ii!"3 -iese) en&ine/ 0ue) is in5ec%ed in%" %he c2)inder/se)0 i&ni%ed as a resu)% "0 c"#*ressi"n6


12/70

E#ui$alent

.

P

W net

.#in .#a(

A%tual &'o%ee

W net

.

P

.#in .#a(

MEP

E#ui$alent * E&

)ean (ffe!tive #ressure, )(# Con!ept

TDC BDCW net = (MEP) x (Displacement Volume)

= (MEP) x (V max -V min )


13/70

Air S%andard O! C,-.eIdeal !%!le of spark ignition engine, !omprises of '- #ro!ess*#ro!ess 1- #sentropic Compression#sentropic Compression $piston moves from 'DC to !DC

#ro!ess -" ! $ constant% &eat added! $ constant% &eat added $piston stays still( represents com)ustion#ro!ess "-' #sentropic e'pansion#sentropic e'pansion $piston moves from !DC to 'DC gives P*"E+#ro!ess '-1 ! $ constant% &eat reection! $ constant% &eat reection $piston stays still( represents E,-.U/! and I0!.1E stroke

s

T

s2#s3 s4#s5

3

2

5

4#in

#out v # c o n

s t6

v #

c o n

s t 6

.

P

v3#v4 v2#v5

3

2

5

4

w out

w in

& $ + = %

& $ + = %

There are only 2-stroke of all4-processes,

TDC BDC


14/70

Ana)2sis "0 Air S%andard O%%" !2c)e +eview of e7uations used8

+.....,-.1

...,-.1/+.......... and

!onstant

gasesIdealof #ro!essIsentropi!

*gasIdeal

0.

s%stem!losed*law1st

fer heat transolumeConstant v

1

1

2+1

1

1

1

1

1

11

""

""

"

"""

−−

=

=

=

=

===

−=

==−=

=⇒=+−=

k k k

k k

k k k

v

v

v

v

P

P

!

!

v

v

P

P

v P v P Pv

&! $! C 7

d! C +!( du Pv

uu7

wconst v

wuu

( )

+

#ressure(ffe!tive)ean

11

,

1

1

,

effi!ien!%Thermal

1

"

1'th

11

111

'"1

th

vv %EP w

7

7

7

7or

k

! ! +w

k

v P v P w

C

C

k c Pv

Pdvw

www

7w

net

-

L

v

pk

net

-

net

−=

−=−=

−−

=

−−

=

==

=+=

=

∫

η

η


15/70

1

1

min

max

13ttoth,

"

'

1

'

"

1

1

1

"

1'1

"

1'

"

1'th

""

1'1'

"

1'th

11

12

121

1

1

1

effi!ien!%Thermal3tto

v

v

r

r

!

!

v

v

v

v

!

!

! $! !

! $! ! ! $!

! $!

! $! C

! $! C

! $! C 7 ! $! C 7

7

7

v

k

v

k k

v

v

v

v

===

−=

=

=

=

−−

−=−

−−=

−−

−=

−= −=

−=

−

−−

η

η

η

1. The higher r v the higher thermal eff.

. The higher r v !ause Self-Ignition

engine kno!k

". 4igher 3!tane 5um$er of fuel used retard

the self-ignition'. T%pi!al r v of gasoline engine 6 .0 7 10.0

8. Thermal effi!ien!% of a!tual spark

ignition engine 6 8-"09


16/70

0e+i!"+

#$ 7ha% is %he di00erence $e%8een %he c)earance .")u#e and %hedis*)ace#en% .")u#e "0 reci*r"ca%in& en&ines92$ -e0ine %he c"#*ressi"n ra%i" 0"r reci*r"ca%in& en&ines61$ :"8 is %he #ean e00ec%i.e *ressure 0"r reci*r"ca%in& en&inesde0ined94$ !an %he #ean e00ec%i.e *ressure "0 an au%"#"$i)e en&ine in"*era%i"n $e )ess %han %he a%#"s*heric *ressure9$ As a car &e%s ")der/ 8i)) i%s c"#*ressi"n ra%i" chan&e9 :"8a$"u% %he #ean e00ec%i.e *ressure93$ 7ha% is %he di00erence $e%8een s*ark4i&ni%i"n and

c"#*ressi"ni&ni%i"n en&ines9$ -e0ine %he 0"))"8in& %er#s re)a%ed %" reci*r"ca%in& en&ines3s%r"ke/ $"re/ %"* dead cen%er/ and c)earance .")u#e6


17/70

O%%" !2c)e;6 7ha% 0"ur *r"cesses #ake %he idea) OTTO c2c)e9

16 :"8 is %he r*# re.")u%i"ns *er #inu%e' "0 an ac%ua) 0"ur4s%r"ke6

&as")ine en&ine re)a%ed %" %he nu#$er "0 %her#"d2na#ic c2c)es97ha% 8"u)d 2"ur ans8er $e 0"r a %8"4s%r"ke en&ine9


18/70

;a6 Indica%ed P"8er6

Indica%ed P"8er IP' 3 P"8er "$%ained a% %he c2)inder6O$%ained 0r"# %he indica%"r dia&ra#6 Gi.en $23

IP PiLANn?C( in 7a%%s 8here Pi is %he indica%ed #ean e00ec%i.e *ressure/in N#1/ L is %he s%r"ke )en&%h/ in #

A is %he area "0 cr"ss sec%i"n "0 %he *is%"n/#1/

N is %he en&ine s*eed in re.#in/ n is %he nu#$er "0 c2)inders and ( ; 0"r 1 s%r"ke and 1 0"r , s%r"ke en&ine6


19/70

;$6 Brake P"8er

Brake P"8er BP' 3 P"8er "$%ained a% %he sha0%6O$%ained 0r"# %he en&ine d2na#"#e%er6

Gi.en $23

BP 1πNT?C in 7a%%s8here T is %he $rake %"rDue/ in N#/ &i.en $2T 76L8here 7 is %he )"ad a**)ied "n %he sha0% $2 %he

d2na#"#e%er/ in N and L is %he )en&%h "0 %he ar# 8here %he )"ad isa**)ied/ in #

N is %he en&ine s*eed/ in re.#in


20/70

;c6 Fric%i"n P"8er

Fric%i"n P"8er FP' 3 P"8er dissi*a%ed as0ric%i"n6 O$%ained $2 .ari"us #e%h"ds)ike M"rse %es% 0"r #u)%i4c2)inder en&ine/

7i))ans )ine #e%h"d 0"r a diese) en&ine/and Re%arda%i"n %es% and M"%"rin& %es%0"r a)) %2*es "0 en&ines6 Gi.en in %er#s "0

IP and BP $23FP IP + BP in 7a%%s


21/70

16 Mean E00ec%i.e Pressure6

Indica%ed Mean E00ec%i.e Pressure IMEP'6 This is a)s"den"%ed $2 Pi and is &i.en $2

Pi Ne% 8"rk "0 c2c)e'S8e*% V")u#e in N#1

The ne% 8"rk "0 c2c)e is %he area under %he P4V dia&ra#6

Brake Mean E00ec%i.e Pressure BMEP'6 This is a)s"den"%ed $2 P$ and is &i.en $2P$ ?C6BP(LANn' N#1 This is a)s" %he $rake *"8er *er uni% s8e*% .")u#e "0 %he

en&ine6Fric%i"n Mean E00ec%i.e Pressure FMEP'6 This is a)s"

den"%ed $2 P0 and is &i.en $2P0 Pi 4 P$ N#1


22/70


23/70

S*eci0ic Fue) !"nsu#*%i"n s0c "rSF!'

This is %he 0ue) c"nsu#ed *er uni% *"8er6Brake S*eci0ic Fue) !"nsu#*%i"n $s0c'6 This is &i.en $2

$s0c #0 BP k&Ji0 BP is in 7 and #0 is in k&s

$s0c is usua))2 Du"%ed in k&k7h6 This is *"ssi$)e i0 BP is in k7 and#0 is in k&h6Indica%ed S*eci0ic Fue) !"nsu#*%i"n is0c'6 This is &i.en $2

is0c #0 IP k&Ji0 IP is in 7 and #0 is in k&s

is0c is a)s" usua))2 Du"%ed in k&k7h6 This is *"ssi$)e i0 IP is in k7and #0 is in k&h6

Mechanica) E00icienc2 in %er#s "0 %he s0c .a)ues is &i.en $2η# is0c$s0c


24/70

S*eci0ic Ener&2 !"nsu#*%i"n sec"r SE!'6

This is %he ener&2 c"nsu#ed *er uni% *"8er6

Brake S*eci0ic Ener&2 !"nsu#*%i"n $sec'6This is &i.en $2

$sec $s0c6c.

7e can si#i)ar)2 de0ine indica%ed s*eci0ic

ener&2 c"nsu#*%i"n isec' and $ased "n%he %8" Duan%i%ies a)s" 8e can de0ine#echanica) e00icienc26


25/70

Air C&%&-i, !5 6!0r7+r!'e -,-.e

E"i"e+

The *"8er/ P/ de.e)"*ed $2 an en&ine is&i.en $2

P"8er 8i)) de*end "n air ca*aci%2 i0 %he

Duan%i%2 in %he $racke% is #a(i#i=ed6 P)"% "0 *"8er .ersus air 0)"8 ra%e isn"r#a))2 a s%rai&h% )ine6

( )ca 9 : % P η =


26/70

V!.0*eri- E55i-ie"-,

Indica%es air ca*aci%2 "0 a , s%r"ke en&ine6 Gi.en $2

Mi is %he #ass 0)"8 ra%e "0 0resh #i(%ure6 N is %he en&ine s*eed in re.uni% %i#e6 Vs is %he *is%"n dis*)ace#en% s8e*% .")u#e'6 Hi is %he in)e% densi%26

is

iv

:

5

)

ρ=η

5:

)

si

i

ρ=


27/70

V")u#e%ric E00icienc2

!an $e #easured3

A% %he in)e% *"r%

In%ake "0 %he en&ine An2 sui%a$)e )"ca%i"n in %he in%ake #ani0")d

I0 #easured a% %he in%ake "0 %he en&ine/ i% is

a)s" ca))ed %he ".era)) .")u#e%rice00icienc26


28/70

V!.0*eri- E55i-ie"-, B&+e8 !"

Dr, Air

Since %here is a )inear re)a%i"nshi* $e%8eenindica%ed "u%*u% *"8er' and air ca*aci%2air0)"8 ra%e'/ i% is #"re a**r"*ria%e %" e(*ress

.")u#e%ric e00icienc2 in %er#s "0 air0)"8 ra%e8hich is %he #ass "0 dr2 air *er uni% %i#e'6Since 0ue)/ air and 8a%er .a*"r "ccu*2 %he

sa#e .")u#e

Va V0 V8 ViThus 8e ha.e3

a)


29/70

i

i

i

a

aaaa

% % v % ====

ρ ρ

:ere Ha is %he densi%2 "0 dr2 air "r %he #ass "0 dr2 air *er uni%.")u#e "0 0resh #i(%ure6Thus/ since

id

iv

:

5)

ρ=η

ad

av

:

5

)

ρ=η∴


30/70

A)s" Vd A*L

s 1LN

;

s

5 =

L is %he *is%"n s%r"ke and s is %he *is%"ns*eed6

s&

)'

;&;

s

)

pa

a

a p

av ρ

=

ρ

=η


31/70

Me&+0re*e" !5 V!.0*eri-

E55i-ie"-, i" E"i"e+

The .")u#e%ric e00icienc2 "0 an en&ine can $ee.a)ua%ed a% an2 &i.en se% "0 "*era%in&c"ndi%i"ns *r".ided and Ha can $eaccura%e)2 #easured6

Me&+0re*e" !5 Air 6.!

Air0)"8 in%" %he en&ine can $e #easured 8i%h%he he)* "0 a sui%a$)e air0)"8 #e%er6 The

0)uc%ua%i"ns in %he air0)"8 can $e reduced8i%h %he he)* "0 sur&e %anks *)aced$e%8een %he en&ine and %he air0)"8 #e%er6

.

a %


32/70

Me&+0re*e" !5 I".e Air De"+i,

B2 -a)%"ns La8 "0 *ar%ia) *ressures3*i *a *0 *8

In %his case *i is %he %"%a) *ressure "0 %he 0resh #i(%ure/ *a is %he *ar%ia) *ressure "0 air in %he #i(%ure/ *0 is %he *ar%ia) *ressure "0 0ue) in %he #i(%ure/

*8 is %he *ar%ia) *ressure "0 8a%er .a*"r in %heair6

Since each c"ns%i%uen% is assu#ed %" $eha.e as a *er0ec%&as/ 8e can 8ri%e

wf a

a

i

a

p p p

p

p

p

++=


33/70

a

aa

oa

% !

+ p/ince

=

f

f f

f

of

:

)T

m


34/70

1/

w

f

f a

a

i

a

%

m

% %

%

p

p -ence

++

=

M indica%es #ass "0 %he su$s%ance/ 1 is %he #")ecu)ar 8ei&h% "0 air/

#0 is %he #")ecu)ar 8ei&h% "0 %he 0ue)/ and; is %he #")ecu)ar 8ei&h% "0 8a%er .a*"r6

1/

1

1

a

w

f a

f i

a

%

%

m %

% p

p

++

=

h-.1m

=1

1

f i +

+

=


35/70

Fi is %he ra%i" "0 #ass "0 0ue) .a*"r %" %ha% "0 dr2 air and h is

%he ra%i" "0 #ass "0 8a%er .a*"r %" %ha% "0 dr2 air a% %he*"in% 8here *i and Ti are #easured6

io

a

ao

aa

! +

p

! +

p 0ow

== ρ

+

+

=

hm :

! +

p

f

i

io

ia

.1

1

1 ρ

This indica%es %ha% %he densi%2 "0 air in %he #i(%ure is eDua)%" %he densi%2 "0 air a% * i and Ti #u)%i*)ied $2 a c"rrec%i"n

0ac%"r/ %ha% is/ %he Duan%i%2 in %he *aren%heses6


36/70

The .a)ue "0 h de*ends "n %he hu#idi%2 ra%i" "0 %he air and is"$%ained 0r"# *s2chr"#e%ric char%s6

F"r c"n.en%i"na) h2dr"car$"n 0ue)s/ %he c"rrec%i"n 0ac%"r isusua))2 ar"und C6/ 8hich is 8i%hin e(*eri#en%a) err"r6F"r diese) en&ines and G-I en&ines/ F i is =er"6

In *rac%ice/ 8i%h s*ark i&ni%i"n en&ines usin& &as")ine and8i%h diese) en&ines %he .")u#e%ric e00icienc2/ ne&)ec%in&%he %er#s in %he *aren%heses/ is &i.en $2

≅η

'

s&

T


37/70

I0 8e d" n"% ne&)ec% %he %er#s in %he *aren%heses 8e &e%%he 0"))"8in& re)a%i"n 0"r .")u#e%ric e00icienc23

+

+

=

hm

:

s .! + p

%

f

i

p

io

i

av

.1

1

1'

η

I0 %he hu#idi%2 is hi&h "r a )"8 #")ecu)ar 8ei&h% 0ue) is usedin a car$ure%ed en&ine/ %he c"rrec%i"n 0ac%"r cann"% $ei&n"red6F"r e(a#*)e/ 8i%h #e%han") a% s%"ichi"#e%ric c"ndi%i"ns

and h C6C1/ %he c"rrec%i"n 0ac%"r is C6>6


38/70

V!.0*eri- E55i-ie"-,9 P!er &"8

Me&" E55e-ive Pre++0re

Since

and

( )!a >=)# η=

s&)'

pa

av ρ=η

( )( ) ( )!av p >=s&'

1# ηρη=∴


39/70

F"r an en&ine/ %he #ean e00ec%i.e *ressure/ #e*/ is &i.en $2

1

0

P

P mep

s

=−=

s&#' p

=

( )( )!av >=ηρη=


40/70

7a2s %" increase *"8er and #e*

The #ean e00ec%i.e *ressure #a2 $e indica%ed"r $rake/ de*endin& "n 8he%her is indica%ed "r$rake %her#a) e00icienc26 Thus/ %he #eane00ec%i.e *ressure is *r"*"r%i"na) %" %he *r"duc%"0 %he in)e% densi%2 and .")u#e%ric e00icienc28hen %he *r"duc% "0 %he %her#a) e00icienc2/ %he0ue)4air ra%i"/ and %he hea% "0 c"#$us%i"n "0 %he0ue) is c"ns%an%6

Fr"# %he *recedin& %8" e(*ressi"ns 8e can0i&ure "u% 8a2s %" increase %he *"8er and #e*"0 an en&ine6


41/70

Back&r"und "n %he O%%" !2c)e

The O%%" !2c)e has 0"ur $asics%e*s "r s%r"kes3 + ;6 An in%ake s%r"ke %ha% dra8s a

c"#$us%i$)e #i(%ure "0 0ue) andair in%" %he c2)inder

+ 16 A c"#*ressi"n s%r"ke 8i%h %he.a).es c)"sed 8hich raises %he%e#*era%ure "0 %he #i(%ure6 As*ark i&ni%es %he #i(%ure %"8ards%he end "0 %his s%r"ke6

+


42/70

!"#*arin& En&ines6

#e* 8"rk d"ne *er uni% dis*)ace#en% .")u#e + Or a.era&e *ressure %ha% resu)%s in %he sa#e a#"un%

"0 indica%ed "r $rake 8"rk *r"duced $2 %he en&ine

+ Sca)es "u% e00ec% "0 en&ine si=e + T8" use0u) %2*es3 i#e* and $#e* i#e*3 indica%ed #ean e00ec%i.e *ressure

+ 4%he ne% 8"rk *er uni% dis*)ace#en% .")u#e d"ne $2 %he &as durin&c"#*ressi"n and e(*ansi"n

$#e*3 $rake #ean e00ec%i.e *ressure + 4%he e(%erna) sha0% 8"rk *er uni% .")u#e d"ne $2 %he en&ine

d)mep

τ π ⋅⋅= '


43/70

BMEP

Based "n %"rDue3

d

)mep τ π ⋅⋅

='

d

(4 stroke)

(2

stroke)d )mep

τ π ⋅⋅

=


44/70

!"#*are

Brake s*eci0ic 0ue) c"nsu#*%i"n $s0c' + Measure "0 en&ine e00icienc2 + The2 are in 0ac% in.erse)2 re)a%ed/ s" a )"8er

$s0c #eans a $e%%er en&ine + O0%en used ".er %her#a) e00icienc2 $ecause

an acce*%ed uni.ersa) de0ini%i"n "0 %her#a)

e00icienc2 d"es n"% e(is%

0

f m

)"

f m)sfc

⋅⋅⋅==

τ π

0 f m

)"

f m)sfc⋅⋅⋅

==τ π


45/70

$s0c

$s0c is %he 0ue) 0)"8 ra%e di.ided $2 %he$rake *"8er

7e can a)s" deri.e %he $rake %her#a)e00icienc2 i0 8e &i.e an ener&2 %" %he 0ue)ca))ed hea% "0 c"#$us%i"n "r/ Dc

"

0

f m

)"

f m)sfc

⋅⋅⋅==

τ π

7c)sfc7c f m

)"

⋅=

⋅=

1

η


46/70

!"#*are

V")u#e%ric E00icienc2/ e. + The #ass "0 0ue) and air induc%ed in%" %he c2)inder

di.ided $2 %he #ass %ha% 8"u)d "ccu*2 %he dis*)aced.")u#e a% %he densi%2 Hi in %he in%ake #ani0")d

+ N"%e i%s a #ass ra%i" and 0"r a , s%r"ke en&ine

+ F"r a direc% in5ec%i"n en&ine

0

mme

d i

f av

ρ

+ +=

0= f m

1 s%r"ke *re#i(ed char&e en&ine


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14s%r"ke *re#i(ed4char&e en&ineh%%*3science6h"8s%u008"rks6c"#%8"4s%r"ke16h%#

1 s%r"ke *re#i(ed char&e en&ine

http://science.howstuffworks.com/two-stroke2.htmhttp://science.howstuffworks.com/two-stroke2.htm


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14s%r"ke *re#i(ed4char&e en&ine

14s%r"kes &i.es 1( as #uch *"8er since "n)2 ;cranksha0% re.")u%i"n needed 0"r ; c"#*)e%e c2c)e .s6 1re.")u%i"ns 0"r ,4s%r"kes'

Since in%ake e(haus% *"r%s are "*en a% sa#e %i#e/s"#e 0ue)4air #i(%ure 0)"8s direc%)2 "u% e(haus% s"#ee(haus% &as &e%s #i(ed 8i%h 0resh &as

Since "i) #us% $e #i(ed 8i%h 0ue)/ "i) &e%s $urned As a resu)% "0 %hese 0ac%"rs/ %her#a) e00icienc2 is )"8er/

e#issi"ns are hi&her/ and *er0"r#ance is near4"*%i#a)0"r a narr"8er ran&e "0 en&ine s*eeds c"#*ared %" ,4s%r"ke en&ines

1 s%r"ke -iese) en&ine


49/70

14s%r"ke -iese) en&ine Used in )ar&e en&ines/ e6&6 )"c"#"%i.es M"re di00erences $e%8een 14s%r"ke

&as")ine .s6 diese) en&ines %han ,4s%r"ke &as")ine .s6 diese) + Air c"#es in direc%)2 %hr"u&h in%ake *"r%s/

n"% .ia crankcase + Mus% $e %ur$"char&ed "r su*erchar&ed %"

*r".ide *ressure %" 0"rce air in%" c2)inder

+ N" "i) #i(ed 8i%h air 4 crankcase has)u$rica%i"n )ike ,4s%r"ke

+ E(haus% .a).es ra%her %han *"r%s 4 n"%necessar2 %" ha.e in%ake e(haus% *a%hs"*en a% sa#e %i#e $u% #a2 d" %his an28a2'

+ Because "n)2 air/ n"% 0ue)air #i(%ure en%ers%hr"u&h in%ake *"r%s/ Qsh"r% circui% "0 in%ake&as "u% %" e(haus% is n"% a *r"$)e#

+ Because "0 %he *re.i"us < *"in%s/ 14s%r"kediese)s ha.e 0ar 0e8er en.ir"n#en%a)*r"$)e#s %han 14s%r"ke &as")ine en&ines

1 s%r"ke -iese) en&ine


50/70

14s%r"ke -iese) en&ine 7h2 can% &as")ine en&ines use c"nce*% si#i)ar %" 14s%r"ke

-iese)9 The2 can in *rinci*)e $u% 0ue) #us% $e in5ec%ed

0ue)air 0u))2 #i(ed a0%er %he in%ake *"r%s are c".ered $u%$e0"re s*ark is 0ired A)s"/ di00icu)% %" c"n%r") ra%i" "0 0ue)aire(haus% residua)

*recise)2 since re)a%i.e a#"un%s "0 e(haus% air )ea.in&e(haus% *"r%s .aries 0r"# c2c)e %" c2c)e due %" %ur$u)ence' 4ra%i" "0 0ue) %" air e(haus%' cri%ica) %" *re#i(ed4char&een&ine *er0"r#ance c"#$us%i"n in n"n4*re#i(ed char&een&ines a)8a2s "ccurs a% s%"ichi"#e%ric sur0aces in ".era)))ean #i(%ures an28a2/ s" n"% an issue 0"r n"n4*re#i(ed

char&e en&ines' S"#e c"#*anies ha.e %ried %" #ake 14s%r"ke *re#i(ed4char&e

en&ines "*era%in& %his 8a2/ e6&6 h%%*38886"r$en&6c"#6au/$u% %hese en&ines ha.e 0"und "n)2 )i#i%ed a**)ica%i"n

http://www.orbeng.com.au/http://www.orbeng.com.au/


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*ara#e%ers See :e28""d !ha*%er 1 0"r #"re de%ai)s !"#*ressi"n ra%i" r c'

Vd dis*)ace#en% .")u#e .")u#e "0 c2)inder s8e*% $2 *is%"n %his is 8ha%

au%" #anu0ac%urers re*"r%/ e6&6 >61 )i%er en&ine #eans >61 )i%ers is c"#$ineddis*)ace#en% .")u#e "0 ALL c2)inders

Vc c)earance .")u#e .")u#e "0 c2)inder NOT s8e*% $2 *is%"n

B"re B' c2)inder dia#e%er S%r"ke L' dis%ance $e%8een #a(i#u# e(cursi"ns "0

*is%"n -is*)ac#en% .")u#e "0 ; c2)inder B1L, i0 B L

%2*ica)'/ >61 )i%er/ 4c2)inder en&ine/ B 6, c#

P"8er An&u)ar s*eed N' ( T"rDue τ' 1Nτ

rc ≡ maximum cylinder volumeminimum cylinder volume = V c +V d V c

P (in horsepower) ≡N (revolutions per minute, RPM) x τ (in foot pounds)

5252


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4en&ines

Piston at bottom

of travelPiston at top

of travel

Bore

StrokeDisplacementvolume

Clearancevolume


53/70

*ara#e%ers En&ine *er0"r#ance is s*eci0ied in $"%h in %er#s "0 *"8erand en&ine %"rDue 4 8hich is #"re i#*"r%an%9

+ 7hee) %"rDue en&ine %"rDue ( &ear ra%i" %e))s 2"u 8he%her 2"ucan c)i#$ %he hi))

+ Gear ra%i" in %rans#issi"n %2*ica))2


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*ara#e%ers Indica%ed 8"rk 4 8"rk d"ne 0"r "ne c2c)e as de%er#ined $2 %he c2)inder P4Vdia&ra# 8"rk ac%in& "n *is%"n 0ace

Note: it’s called “indicated” power because historically (before

oscilloscopes) the P and V were recorded by a pen moving in the

direction as V changed and moving in the y direction as P changed! "he

P#V plot was recorded on a card and the area inside the P#V was the

“indicated” wor$ (usually measured by cutting out the P#V and

weighting that part of the card%)

Ne% indica%ed 8"rk 7i/ne% PdV ".er 8h")e c2c)e ne% area inside P4Vdia&ra#

Indica%ed 8"rk c"nsis%s "0 1 *ar%s + Gr"ss indica%ed 8"rk 7 i/&r"ss 4 8"rk d"ne durin& *"8er c2c)e

+ Pu#*in& 8"rk 7i/* 4 8"rk d"ne durin& in%akee(haus% *u#*in& c2c)e

7i6ne% 7i/&r"ss 4 7i/*u#*

Indica%ed *"8er 7i/(Nn/ 8here ( c"u)d $e ne%/ &r"ss/ *u#*in& and n 1 0"r,4s%r"ke en&ine/ n ; 0"r 1 s%r"ke en&ine since ,4s%r"ke needs 1 c"#*)e%ere.")u%i"ns "0 en&ine 0"r "ne c"#*)e%e %her#"d2na#ic c2c)e as seen "n P4Vdia&ra# 8hereas 14s%r"ke needs "n)2 ; re.")u%i"n'

En&ine desi&n *er0"r#ance


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En&ine desi&n *er0"r#ance*ara#e%ers Ani#a%i"n3 &r"ss ne% indica%ed 8"rk/

*u#*in& 8"rk

G r " s s i n d i c a % e d 8

" r k

G r " s s i n d i c a % e d 8 " r k Pu#*in& 8"rkPu#*in& 8"rk

N e % i n d i c a % e d 8 " r k

N e % i n d i c a % e d 8 " r k I ' I '

4'4'



56/70

En&ine desi&n *er0"r#ance*ara#e%ers

Brake 8"rk 7$' "r $rake *"8er P$' 8"rk *"8er %ha% a**ears a% %hesha0% a% %he $ack "0 %he en&ine

:is%"rica))2 ca))ed Q$rake $ecause a #echanica) $rake )ike %ha% "n 2"urcar 8hee)sW 8as used in )a$"ra%"r2 %" si#u)a%e %he Qr"ad )"ad %ha% 8"u)d$e *)aced "n an en&ine in a .ehic)e'

7ha%s %he di00erence $e%8een $rake and indica%ed 8"rk "r *"8er9FRI!TION

+ Gr"ss Indica%ed 8"rk $rake 8"rk 0ric%i"n 8"rk 7 0 '7i/& 7$ 70 + N"%e %ha% %his de0ini%i"n "0 0ric%i"n 8"rk inc)udes n"% "n)2 %he Qru$$in& 0ric%i"n $u% a)s"

%he *u#*in& 8"rk I *re0er

7i/& 7$ 70 7*

8hich se*ara%es ru$$in& 0ric%i"n 8hich cann"% $e seen "n a P4V dia&ra#' 0r"#

*u#*in& 0ric%i"n 8hich IS seen "n %he P4V' + The )a%%er de0ini%i"n #akes 0ric%i"n %he di00erence $e%8een 2"ur ac%ua) $rake'

8"rk*"8er "u%*u% and %he 8"rk seen "n %he P4V + N"%e %he 0ric%i"n 8"rk a)s" inc)udes 8"rk*"8er needed %" dri.e %he c"")in& 0an/ 8a%er

*u#*/ "i) *u#*/ &enera%"r/ air c"ndi%i"ner/

+ M"ra) 4 kn"8 8hich de0ini%i"n 2"ure usin&



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Mechanica) e00icienc2 $rake *"8er' indica%ed *"8er' 4#easure "0 i#*"r%ance "0 0ric%i"n )"ss

Ther#a) e00icienc2 η%h' 8ha% 2"u &e% 8ha% 2"u *a2 0"r' *"8er "u*u%' 0ue) hea%in& .a)ue in*u%'

S*eci0ic 0ue) c"nsu#*%i"n s0c' #d"%0ue)'P"8er'

uni%s usua))2 *"unds "0 0ue) *er h"rse*"8er4h"ur 2ukX'

N"%e a)s"

η th ≡Power output (brake or indicated)

Ý mfuelQ R

isfc ≡ mfuel

indicated power;bsfc ≡

mfuel

brake power

η th,i ≡1

(isfc)Q R ;η th,b ≡

1

(bsfc)Q R



58/70


V")u#e%ric e00icienc2 η.' #ass "0 air ac%ua))2 dra8n in%" c2)inder' #ass "0 air %ha% idea))2 c"u)d $e dra8n in%" c2)inder'

8here ρair is a% a#$ien% c"ndi%i"ns Pa#$ien%RTa#$ien%

V")u#e%ric e00icienc2 indica%es h"8 8e)) %he en&ine Q$rea%hes 4 8ha%)"8ers η. $e)"8 ;CCY9 + Pressure dr"*s in in%ake s2s%e# e6&6 %hr"%%)in&' in%ake .a).es + Te#*era%ure rise due %" hea%in& "0 air as i% 0)"8s %hr"u&h in%ake s2s%e# + V")u#e "ccu*ied $2 0ue)

+ N"n4idea) .a).e %i#in& + Q!h"kin& air 0)"8 reachin& s*eed "0 s"und' in *ar% "0 in%ake s2s%e# ha.in&

s#a))es% area *assin& in%ake .a).es'

See 0i&ure "n *6 1;@ "0 :e28""d 0"r &""d su##ar2 "0 a)) %hese e00ec%s

η v ≡ mair (measured)

ρ air V

d N / n



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Mean e00ec%i.e *ressure MEP'

P"8er c"u)d $e $rake/ indica%ed/ 0ric%i"n "r *u#*in& *"8er/ )eadin& %" BMEP/IMEP/ FMEP/ PMEP

N"%e P"8er T"rDue ( 1N/ %hus

Brake %"rDue BMEPVd1n MEP can $e in%er*re%ed as %he 0irs% #"#en% "0 *ressure 8i%h res*ec% %" c2)inder

.")u#e/ "r a.era&e *ressure/ 8i%h .")u#e as %he 8ei&h%in& 0unc%i"n 0"r %hea.era&in& *r"cess

MEP ≡Work per cycle

Displacement volume =

PdV cycle

V d

=(Power )n / N

V d

=(Power )n

V d N

MEP ≡(Work per cycle)/m

(Displacement volume)/m= ρ intake(Work per cycle)/m



60/70


MEP is use0u) 0"r 1 reas"ns + Since i%s *r"*"r%i"na) %" *"8er "r 8"rk/ 8e can add and

su$%rac% *ressures 5us% )ike 8e 8"u)d *"8er "r 8"rk + M"re i#*"r%an%' I% n"r#a)i=es "u% %he e00ec%s "0 en&ine

si=e Vd'/ s*eed N' and 14s%r"ke .s6 ,4s%r"ke n'/ s" i%*r".ides a 8a2 "0 c"#*arin& di00eren% en&ines and"*era%in& c"ndi%i"ns

T2*ica) ,4s%r"ke en&ine/ IMEP ;1C )$in1 a%#

4 h"8 %" &e% #"re9 Tur$"char&e 4 increase Pin%ake a$".e ; a%#/ #"re 0ue) air s%u00ed in%" c2)inder/#"re hea% re)ease/ #"re *"8er



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Pu#*in& *"8er *u#*in& 8"rk'N'n ∆P'∆V'N'n Pe(haus% 4 Pin%ake'VdNn

$u% PMEP *u#*in& *"8er'nVdN'/ %hus PMEP Pe(haus% 4 Pin%ake'

8asn% %ha% eas29' %his assu#es Q*u#*in& )""* is a rec%an&)e' Es%i#a%e "0 IMEP

T2*ica) en&ine a% 8ide4"*en %hr"%%)e P in%ake Pa#$ien%'3η%h/i/& Y/ 0 C6C? a% s%"ichi"#e%ric'/R ,6> ( ;C@ Jk&/ R 1@ Jk&4K/ Tin%ake


62/70


E#issi"ns *er0"r#ance usua))2 re*"r%ed in &ra#s "0 *"))u%an%e#i%%ed *er $rake h"rse*"8er4h"ur 2ukX' "r &ra#s *er ki)"8a%%h"ur s)i&h%)2 )ess 2uk'/ e6&6

Brake S*eci0ic NO( BSNO(' #d"%NO( Brake *"8er'

One can a)s" %hink "0 %his as #ass%i#e' ener&2%i#e' #ass ener&2 &ra#s "0 *"))u%an% *er J"u)e "0 8"rk d"ne $u% En.ir"n#en%a) Pr"%ec%i"n A&enc2 s%andards 0"r *assen&er

.ehic)es' are in %er#s "0 &ra#s *er #i)e/ n"% $rake *"8er h"ur/%hus s#a))er cars can ha.e )ar&er BSNO( "r BS!O/ BS:!/ e%c6'

$ecause *resu#a$)2' )ess h"rse*"8er %hus )ess 0ue)' is needed%" #".e %he car a cer%ain nu#$er "0 #i)es in a cer%ain %i#e Lar&er .ehic)es and s%a%i"nar2 en&ines 0"r *"8er &enera%i"n' are

re&u)a%ed $ased "n $rake s*eci0ic e#issi"ns direc%)2


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F"ur4S%r"ke -iese) En&ine

In%ake s%r"ke + In%ake .a).e "*en/ e(haus% .a).e shu% + Pis%"n %ra.e)s 0r"# T-! %" B-!

+ Air dra8n in

!"#*ressi"n s%r"ke + In%ake and e(haus% .a).es shu%

+ Pis%"n %ra.e)s 0r"# B-! %" T-! + Te#*era%ure and *ressure "0 air increase


64/70


P"8er s%r"ke + In%ake and e(haus% .a).es shu% + Fue) in5ec%ed in%" c2)inder and i&ni%es

+ Pis%"n 0"rced 0r"# T-! %" B-! E(haus% s%r"ke

+ In%ake .a).e shu%/ e(haus% .a).e "*en

+ Pis%"n #".es 0r"# B-! %" T-! + !"#$us%i"n &ases e(*e))ed


65/70


S%r"kes + In%ake + !"#*ressi"n

+ P"8er + E(haus%


66/70

T8"4S%r"ke -iese) En&ine

; *"8er s%r"ke e.er2 cranksha0% re.")u%i"n.ice e.er2 %8" 8 ,4s%r"ke'

Uses *ressuri=ed air %" si#u)%ane"us)2

su**)2 ne8 air and e(*e) c"#$us%i"n &ases Sca.en&in&

+ E(haus% .a).e "*en/ in)e% *"r% e(*"sed +

Pressuri=ed air en%ers/ e(*e)s c"#$us%i"n&ases + Pis%"n near B-!


67/70


!"#*ressi"n + In%ake and e(haus% .a).es shu% + Pis%"n %ra.e)s 0r"# B-! %" T-!

+ Te#*era%ure and *ressure "0 air increase P"8er s%r"ke

+ In%ake and e(haus% .a).es shu%

+ Fue) in5ec%ed in%" c2)inder and i&ni%es + Pis%"n 0"rced 0r"# T-! %" B-!


68/70


S%r"kes + !"#*ressi"n

+ P"8er + In%akeE(haus%'


69/70

T8" .s6 F"ur4S%r"ke En&ines

T8"4s%r"ke ad.an%a&es + :i&her *"8er %" 8ei&h% ra%i"

+ Less c"#*)ica%ed .a).e %rain F"ur4s%r"ke ad.an%a&es

+ M"re e00icien% $urnin& *r"cess

+ As si=e increases/ *"8er4%"48ei&h% ra%i"i#*r".es


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Gas")ine .s6 -iese) En&ine

51656498 Motor Bakar Torak

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