effect of different turbulence models on combustion chamber ...
DETERMINING ENGINE CONDITION. COMBUSTION CHAMBER EFFICIENCY B AFFECTED BY: AIR/FUEL MOVEMENTAIR/FUEL...
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Transcript of DETERMINING ENGINE CONDITION. COMBUSTION CHAMBER EFFICIENCY B AFFECTED BY: AIR/FUEL MOVEMENTAIR/FUEL...
COMBUSTION CHAMBER COMBUSTION CHAMBER EFFICIENCY EFFICIENCY
AFFECTED BY:AFFECTED BY:• AIR/FUEL MOVEMENTAIR/FUEL MOVEMENT• COMBUSTION TURBULENCECOMBUSTION TURBULENCE• INTAKE DESIGNINTAKE DESIGN• EGREGR• COMBUSTION CHAMBER DESIGNCOMBUSTION CHAMBER DESIGN
MANUAL COMPRESSION MANUAL COMPRESSION TESTING (CYL. SEALING)TESTING (CYL. SEALING)
EASIEST MANUAL TEST IS A VACUUM EASIEST MANUAL TEST IS A VACUUM TESTTEST
EACH CYLINDER IS A INDIVIDUAL AIR EACH CYLINDER IS A INDIVIDUAL AIR PUMPPUMP
THERE MUST BE A GOOD CYLINDER THERE MUST BE A GOOD CYLINDER SEAL TO HAVE GOOD VACUUMSEAL TO HAVE GOOD VACUUM
ANY CYLINDER LEAK WILL SHOW ON ANY CYLINDER LEAK WILL SHOW ON VACUUM GAUGEVACUUM GAUGE
VACUUMVACUUM
Measured in Inches of Mercury (Hg)Measured in Inches of Mercury (Hg) A Reduction of 1 inch of vacuum A Reduction of 1 inch of vacuum
per 1000 feet increase in altitudeper 1000 feet increase in altitude Pounds Per Square Inch Absolute Pounds Per Square Inch Absolute
(PSIA) (PSIA) Air moves rapidly from a High Air moves rapidly from a High
pressure to a low pressurepressure to a low pressure
C24-25
VACUUM TESTING VACUUM TESTING PROCEDURESPROCEDURES
CRANKING VACUUMCRANKING VACUUM IDLE VACUUMIDLE VACUUM IDLE THROTTLE ANGLE CHECKIDLE THROTTLE ANGLE CHECK 2500 RPM VACUUM2500 RPM VACUUM PISTON RING TESTPISTON RING TEST IDLE/DRIVE TESTIDLE/DRIVE TEST CRUISE TESTCRUISE TEST VAC AT W.O.T. AND AFTER W.O.T.VAC AT W.O.T. AND AFTER W.O.T.
L138
TYPICAL VACUUM TYPICAL VACUUM READINGSREADINGS
CRANKING VACUUM 3-5”CRANKING VACUUM 3-5” IDLE VACUUM 18”IDLE VACUUM 18” IDLE THROTTLE ANGLE 0”IDLE THROTTLE ANGLE 0” 2500 RPM VACUUM 20”2500 RPM VACUUM 20” VAC TEST PROCEDURE CAN VAC TEST PROCEDURE CAN
IDENTIFY POTENTIAL PROBLEMSIDENTIFY POTENTIAL PROBLEMS COMPRESSION TEST CAN PINPOINTCOMPRESSION TEST CAN PINPOINT
READING COMPRESSION READING COMPRESSION GAUGEGAUGE
1ST PUFF - SHOULD BE 50% OF 1ST PUFF - SHOULD BE 50% OF FINAL PUFF (INDICATOR OF FINAL PUFF (INDICATOR OF CYLINDER WALL AND RINGS)CYLINDER WALL AND RINGS)
ALL READINGS UNIFORMALL READINGS UNIFORM IF REAL HIGH - CARBON BUILD-UPIF REAL HIGH - CARBON BUILD-UP IF CHANGE ON ONE CYL - IF CHANGE ON ONE CYL -
POSSIBLE STICKING VALVEPOSSIBLE STICKING VALVE
COMPRESSION AND VACUUMCOMPRESSION AND VACUUM BOTH REQUIRE GOOD CYLINDER SEALBOTH REQUIRE GOOD CYLINDER SEAL LACK OF CYLINDER SEAL WILL LACK OF CYLINDER SEAL WILL
PREVENT PRESSURE TO RISE HIGH PREVENT PRESSURE TO RISE HIGH ENOUGH TO IGNITE THE MIXTUREENOUGH TO IGNITE THE MIXTURE
COMPRESSION & VAC TEST INDICATES COMPRESSION & VAC TEST INDICATES CYLINDER SEAL, RUNNING CYLINDER SEAL, RUNNING COMPRESSION TEST INDICATES COMPRESSION TEST INDICATES VOLUMETRIC EFFICIENCYVOLUMETRIC EFFICIENCY
MANUAL CYLINDER MANUAL CYLINDER BALANCEBALANCE
SHORTING PLUG ONE BY ONESHORTING PLUG ONE BY ONE TIME CONSUMINGTIME CONSUMING DON’T OPEN CIRCUIT SECONDARY DON’T OPEN CIRCUIT SECONDARY
CIRCUITCIRCUIT WILL PINPOINT LOW POWER WILL PINPOINT LOW POWER
OUTPUT OF A CYLINDEROUTPUT OF A CYLINDER
OTHER CYLINDER OTHER CYLINDER BALANCE TESTSBALANCE TESTS
ELECTRONICALLY PERFORMED BY ELECTRONICALLY PERFORMED BY ENGINE ANALYZERENGINE ANALYZER• CRANKING TESTCRANKING TEST• AMPS PER CYLINDERAMPS PER CYLINDER• RELATIVE COMPRESSIONRELATIVE COMPRESSION
CYLINDER CYLINDER CONTRIBUTIONCONTRIBUTION FUEL DISTRIBUTIONFUEL DISTRIBUTION DUAL PLANEDUAL PLANE SINGLE PLANESINGLE PLANE LOW RISELOW RISE HIGH RISEHIGH RISE
COMPUTER CONTROLLED COMPUTER CONTROLLED ENGINE POWER BALANCEENGINE POWER BALANCE
DISCONNECT O2 SENSORDISCONNECT O2 SENSOR INITIAL TIMING MODEINITIAL TIMING MODE DISCONNECT EGRDISCONNECT EGR STABILIZE MAP IF APPLICABLESTABILIZE MAP IF APPLICABLE STABILIZE FUEL PRESSURESTABILIZE FUEL PRESSURE STABILIZE IDLE CONTROLSTABILIZE IDLE CONTROL PREFERRED TEST RPM 800-1200 RPMPREFERRED TEST RPM 800-1200 RPM
MANUAL TEST OF MANUAL TEST OF VOLUMETRIC EFFICIENCYVOLUMETRIC EFFICIENCY
CAN TEST AT:CAN TEST AT:•CRANKINGCRANKING•IDLEIDLE•SNAP ACCELERATIONSNAP ACCELERATION
CRANKING COMPRESSION CRANKING COMPRESSION TESTTEST
SLOW CRANKSHAFT SLOW CRANKSHAFT SPEED/CYLINDER COMPLETELY SPEED/CYLINDER COMPLETELY FILLS/ HIGH COMPRESSIONFILLS/ HIGH COMPRESSION
CHECK OVERALL MECHANICAL CHECK OVERALL MECHANICAL CONDITIONCONDITION
CHECKS FOR LEAKSCHECKS FOR LEAKS
IDLING COMPRESSIONIDLING COMPRESSION
AIR RESTRICTED BY THROTTLE AIR RESTRICTED BY THROTTLE PLATEPLATE
CRANKSHAFT SPEED 4 TO 5 TIMES CRANKSHAFT SPEED 4 TO 5 TIMES CRANKING SPEEDCRANKING SPEED
LESS AIR ENTERING CYL PER LESS AIR ENTERING CYL PER ENGINE CYCLEENGINE CYCLE
TYPICALLY 50 TO 60 PSITYPICALLY 50 TO 60 PSI
CON’T NEXT SLIDE
IDLE TEST, CONT’DIDLE TEST, CONT’D
MUST “BURP” GAUGEMUST “BURP” GAUGE IF RPM BROUGHT UP SLOWLY TO IF RPM BROUGHT UP SLOWLY TO
1500 RPM, PRESSURE GOES DOWN 1500 RPM, PRESSURE GOES DOWN TO ABOUT 40 PSI.TO ABOUT 40 PSI.
NO MANUFACTURER’S SPEC NO MANUFACTURER’S SPEC COMPARE WITH OTHER CYLINDERSCOMPARE WITH OTHER CYLINDERS
SNAP ACCELERATIONSNAP ACCELERATION QUICKLY SNAP-OPEN THROTTLE, THIS QUICKLY SNAP-OPEN THROTTLE, THIS
REMOVES THROTTLE PLATE REMOVES THROTTLE PLATE RESTRICTIONRESTRICTION
READINGS SHOULD INCREASE TO 80% READINGS SHOULD INCREASE TO 80% OF CRANKING COMPRESSIONOF CRANKING COMPRESSION
HIGH READING:RESTRICTION IN HIGH READING:RESTRICTION IN EXHAUST OR VALVE TRAINEXHAUST OR VALVE TRAIN
LOW READINGS: RESTRICTED INTAKE LOW READINGS: RESTRICTED INTAKE OR CARBON ON VALVEOR CARBON ON VALVE