Defects Reading From Indicator Diagram

DEFECTS READING FROM INDICATOR INDICAT OR DIAGRAM INDICA INDIC ATOR DI AGRAM Explain the following defects on the indicator diagrams and the engine itself. Use diagrammatic sketches as necessary. (a) (a) Earl Early y Fuel Fuel Inje Inject ctio ion n (b) (b) ate ate Fuel Fuel Inje Inject ctio ion n (c) (c) !hok !hoked ed Exha Exhaus ustt "ort "ort (d) (d) !hok !hoked ed Inle Inlett "ort "ort (e) !hoke Fuel #al$e ( f) eaky fuel $al$e (g) %fter &urning (h) eaky "iston 'ing (i) Incorrect tappet clearance (k) !arbon encrusted ole Early injection ( or ) Early Ignition

*etection+

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ymp ympto toms ms++

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!au !auses+ ses+

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Effect to

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'emedy

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It can be detected by taking power card and draw card. "ower card shows peak pressure is higher than normal. *raw card shows more clearly start of injection and ignition occur before -*!. ow expansion line indicate in diagram

Exha Exhaus ustt temp temper erat atur ure e lowe lowerr than than norm normal al Engine running with knocking sound and $ibration / due to hea$y shock load to bearings being ignition occurs before -*! Inco Incorrrect fuel fuel pump ump timi timing ng or wrong #I#I- sett settiing Incorrect fuel $al$e setting or spring broken "oor fuel condition ( 0igh !etane o. ) Incorrect fuel temperature and $iscosity control.

1$erheating parts within cylinder  ca$enge fire 'unning gears and bearings may damage due to shock load transmission and $ibration. Engine power increase according to increasing of thermal efficiency !orrect fuel pump timing Inspect fuel $al$e and pressure test !orrect fuel temperature and $iscosity control. !orrect cooling temperature of working parts.

!ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM Late Injection ( or ) Late Ignition

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ymptoms+

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!auses by

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Effect to

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'emedy

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It can be detected by taking power card and draw card. "ower card shows decrease in high of peak pressure than normal. *raw card shows more clearly low peak pressure than normal/ slight dip in compression line before fuel injection begins and ignition start well after -*!.

0igh exhaust temperature with black smoke emission "ulsation in exhaust manifold due to high exhaust pressure. In correct fuel pump timing / worn or defecti$e fuel pump3s internal parts Faulty fuel $al$e ( 0igh setting pressure ) Incorrect fuel $iscosity and temperature control ( -oo ow ) &ad fuel condition ( ow !etane o. ) "oor compression ack of sca$enge air  Excess chain slackness Under cooling of engine parts. 'educe engine power out put 'educe -urbocharger efficiency and cause surging Fouling of exhaust system which may lead to uptake fire  %fter burning effect which may lead to exhaust $al$e burning 0igh temperature in liner which may lead to defect cylinder lubrication. Engine power decrease due to decreasing of thermal efficiency !orrect fuel pump timing and o$erhaul fuel pump. Inspect fuel $al$e and pressure test !orrect fuel temperature and $iscosity control 2aintain correct cooling temperature Inspect chain slackness 4 readjust as necessary. 5eep correct maintenance 4 cleaning to charge air cooler / sca$enge space and exhaust system

!ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM Choke E!ha"#t $ort ( Late Ti%ing )

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ymptoms

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!aused by

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Effect to

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'emedy

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It can be detected by light spring card. It shows exht. pressure does not falls rapidly as normal and pre$ent blow down of exhaust gas 0igh exhaust temperature and hea$y smoke emission with soot coming out . 0igh temperature to internal working parts. -urbocharger r.p.m reduce and surging Incorrect tappet clearance Faulty fuel injection system ack of sca$enge air  Excess cylinder lubrication Exhaust system fouling !am clearance too much for uni,flow type engine. Engine blow pass which may lead to sca$enge fire. *ecrease engine power output. !orrection of tappet clearance !orrect fuel timing and good fuel injection !orrect cylinder lubrication 5eep good cleanliness of sca$enge space / turbocharger and exhaust grid oot cleaning of exhaust gas boiler and uptake

Choke Inlet $ort ( Lo## o& Sca'enge Air )

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ymptoms

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Effect

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'emedy

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It can be detected by taking light spring card. It shows insufficient pressure of sca$enge air entering than normal. 0igh exhaust temperature and black smoke emission. Engine speed can not increase normal 5nocking sound may occur in some case. Inlet sca$enge ports fouling with incomplete combustion products 1bstruction may ha$e inlet air manifold. Improper cleaning of sca$enge spaces  %ir cooler fouling -urbocharger fouling at blower side 6.ect. *ue to star$ation of air / engine can not perform with complete combustion. In correct air 4 fuel ratio may cause engine running unbalance and decrease engine power out *ue to incomplete combustion products / internal corrosion of engine parts / ring sticking / contamination 66..may occur. !orrect maintenance and cleaning of -urbocharger including water washing 'egular cleaning %ir cooler / ca$enge spaces and inlet ports !ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM Incorrect Taet Clearance

*etection

, &y taking light spring card , &y checking tappet clearance while in port

ymptom

, 0earing noise of tappet , Exhaust and inlet air abnormal , *ump sound in air inlet manifold for normally aspirated engine

!aused by

, Irregular maintenance check to engine , Excess wear and tare of the followings being caused by star$ation of .1 , 'ocker arm bush , "in ball at rocker arm , !up at push rod , #al$e seat and guide for exhaust and suction $al$e , &roken spring..

Effect to

, Incorrect timing of opening and closing to inlet and exhaust $al$e. , Early opening of inlet $al$e may cause low sca$enge efficiency / high sca$enge space temperature and choke to suction $al$e. , ate opening of inlet $al$e may cause low sca$enge efficiency / remain exhaust gas / lack of fresh air for combustion lead to poor combustion and black smoke . , Early opening of exhaust $al$e may cause loss of power since pressure is released too soon. It will gi$e high exhaust temperature with the risk of o$erheating and contamination. , ate opening of exhaust $al$e will increase thermal load / o$erheat in unit / reduce sca$enge air efficiently by reducing blow down. It will also effect energy supply to turbocharger.

'emedy , %lways check and readjusted tappet clearance according to recommended '.0 , %lways check and regulate the necessity of .1 for rocker arm / $al$es and tappet mechanism. Leaky $i#ton Ring

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ymptom

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!aused by

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Effect to

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'emedy

&y taking !ompression card / "ower card 4 *raw card without fuel supply. 2easure compression pressure and compare to other unit. 0igh exhaust temperature with smoke.  %ll units3 exhaust temperature not steady Excess liner wear and tare Excess wear of piston rings and ring groo$es "iston ring jamming or sticking due to carbon deposit Engine blow pass ca$enge fire 0igh rate of cylinder wear being insufficient lubrication due to blow pass "iston and liner o$erheat and may cause seiure.

, 1$erhaul unit ( !lean 4 measure iner calibration / "iston 7roo$e / "iston 'ing width 8 thickness 7ap / 'ing to groo$e clearance ) 'enew excess limited parts. 2easure cylinder lubricating rate and correct as necessary  %$oid running o$erload. !ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM A&ter "rning

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ymptoms

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Effect to

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'emedy

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&y taking "ower card and *raw card. 'ise expansion line indicate after burning condition during the expansion stroke . Exhaust temperature higher than normal Emission of smoky exhaust -urbocharger surging Incorrect fuel pump timing eaky fuel $al$e Exhaust $al$e burning Fouling the exhaust gas system and lead to uptake fire &urning of piston crown !orrosion of liner and piston rings due to burning away of lubricating oil film being internal parts o$erheating. !hange fuel $al$e !orrect fuel pump timing 2aintain correct cooling temperature

Leaky F"el *al'e

*etection 9

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&y taking "ower card and *raw card It show the fluctuation of pressure during expansion process due to after burning of leaky fuel.

ymptoms

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0igh exhaust temperature with black smoke emission. 5nock of pressure wa$e in the fuel injection system.

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!aused by

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Effect to

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'emedy

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Incorrect opening pressure setting of fuel $al$e. ( -oo ow or pring &roken ) "artial opening of fuel $al$e by small debris at needle $al$e and forming carbon deposit by back pressure hot gas from combustion. %fter burning "roduce incomplete combustion products Fouling at inlet and exhaust ports 'educe -urbocharger efficiency !arbon encrusted nole Inspect fuel $al$e / o$erhaul and pressure test / !hange if necessary. 2aintain correct fuel temperature 5eep good fuel $al$e cooling temperature 5eep good fuel purification and separation !ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM Choke F"el *al'e ( or ) Choke +,$ Filter

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ymptoms 9

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!aused by

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Effect to

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'emedy

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&y taking "ower card 4 *raw card. It show irregularities at the peak of the diagrams. ower exhaust temperature than normal 0ammering of high pressure pipe between fuel pump and injector. Engine speed not steady. mall debris choke at fuel atomier holes or high pressure filter. eaky fuel $al$e recei$ing hot gas being blow back pressure from combustion process and forming carbon deposits. ticking of fuel $al$e being o$erheating. Engine running with unbalance output 'educe engine power output Inspect fuel $al$e / o$erhaul 4 pressure test !hange fuel $al$e if necessary !lean all filter and strainers in F.1 system. 2aintain efficient fuel separation 2aintain good fuel $al$e cooling.

Car-on Encr"#te No..le,

*etection

, &y taking of "ower card 4 *raw card , !an roughly determine form improper cur$e of combustion line due to poor fuel atomiation and spray pattern. , It is usually seen in engines using high $iscosity fuel.

ymptom

, *ue to poor combustion / smoky exhaust with high temperature and increased fuel consumption.

!aused by

, &y the construction of a nole / there is a small space between $al$e seat and space holes / called sac. %fter injecting fuel / the sec contain fuel is o$erheated by blow back of combustion gas/ and forming carbon around the holes. -his trouble is caused by high fuel $al$e cooling temperature.  ,-he secondary cause is poor closing of fuel $al$e / i.e / sluggish shut off / and fuel dribble. If secondary cause is present with the first / serious combustion problem may arise. -he formation of carbon gradually built up and interfere spray pattern and atomiation.

'emedy

, Fuel injectors to be cleaned and pressure test in regular inter$al. , !hange with o$erhaul spares at rated running hour  , Fuel $al$e cooling system to be perfect. , %lways maintain fuel $al$e cooling rated temperature. , !leaning and upgrading of F.1 to be care (sedimentation / filtration / purification and chemical treatment process ) , 5eep correct temperature and $iscosity of fuel oil 6.

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!ho 2yint First Engineer  2.F..

DEFECTS READING FROM INDICATOR DIAGRAM

!ho 2yint First Engineer  2.F..