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NVH METHODOLOGY FLOWCHARTS

NVH METHODOLOGY FLOWCHARTS. DECEMBER 4, 2006. RUN THE VEHICLE AT THE FOLLOWING OPERATING CONDITIONS: FULL LOAD SWEEP NO LOAD SWEEP IDLE 1200 RPM WOT 1500 RPM WOT 1800 RPM WOT 2100 RPM WOT. SETUP TRUCK ON CHASSIS ROLLS DYNO.

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NVH METHODOLOGY FLOWCHARTS

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  1. NVH METHODOLOGY FLOWCHARTS DECEMBER 4, 2006 Detroit Diesel Standard Template.ppt

  2. RUN THE VEHICLE AT THE FOLLOWING • OPERATING CONDITIONS: • FULL LOAD SWEEP • NO LOAD SWEEP • IDLE • 1200 RPM WOT • 1500 RPM WOT • 1800 RPM WOT • 2100 RPM WOT SETUP TRUCK ON CHASSIS ROLLS DYNO INSTALL TRIAXIAL ACCELEROMETER ON ACTIVE (ENGINE) SIDE AND PASSIVE (FRAME) SIDE OF EACH MOUNT SELECT TEST VEHICLE FOR EACH MOUNT CALCULATE TRANSMISSIBILITY: DIVIDE ACCELERATION OF FRAME SIDE BY ACCELERATION OF ENGINE SIDE IN X,Y,Z DIRECTIONS PLOT TRANSMISSIBILITY (X,Y,Z DIRECTIONS) AS A FUNCTION OF FREQUENCY (0-500 Hz) COLLECT ACCELERATION DATA AT EACH RESPONSE POINT IN THE X,Y,Z DIRECTIONS IS TRANS. > 0.5 ABOVE 1.4 x NAT. FREQ. OF ISOLATOR? MODIFY: -MOUNT STIFFNESS (i.e. LOWER DUROMETER) -ALTER MOUNT DESIGN (COMPRESSION VS. SHEAR) RE-INSTALL ON VEHICLE YES NO ISOLATORS EFFECTIVE AT VIBRATION ATTENUATION ENGINE MOUNT VIBRATIONOPERATING ENGINE VIBRATION EVALUATION Detroit Diesel Standard Template.ppt

  3. RUN THE VEHICLE AT THE FOLLOWING • OPERATING CONDITIONS: • OVER THE ROAD, 60 MPH, 7TH GEAR (WITH LOADED TRAILER) • FULL THROTTLE ACCELERATION 1000RPM-2100RPM • STATIONARY (IDLE, 1200RPM, 1800RPM, 2100RPM) SETUP TRUCK ON SMOOTH ROAD INSTALL MICROPHONE AT DRIVER’S RIGHT EAR LOCATION SELECT TEST VEHICLE CROSS-PLOT: -OVERALL SPL -THIRD OCTAVES -SQ METRICS VS. FTL TARGET CURVES BEST-IN-CLASS CURVES FOR EACH CONDITION CALCULATE: -ONE THIRD OCTAVE SPECTRA -SOUND QUALITY METRICS (LOUDNESS, SHARPNESS) COLLECT A-WEIGHTED SOUND PRESSURE LEVEL AT EACH CONDITION MODIFY: -MOUNT STIFFNESS (i.e. LOWER DUROMETER) -REDUCE STRUCTURAL VIBRATION LEVELS -REDUCE GEAR RATTLE -ADD C.L.D. TREATMENTS, BARRIERS DO ANY METRICS EXCEED TARGET VALUES OR B.I.C? INTERIOR SOUND LEVELS MEET OR EXCEED TARGET VALUES AND/OR BEST IN CLASS YES NO TRUCK CABIN NOISEOPERATING TRUCK SOUND LEVEL EVALUATION Detroit Diesel Standard Template.ppt

  4. RUN THE VEHICLE AT THE FOLLOWING • OPERATING CONDITIONS: • FULL LOAD SWEEP • NO LOAD SWEEP • IDLE • 1200 RPM WOT • 1500 RPM WOT • 1800 RPM WOT • 2100 RPM WOT SETUP TRUCK ON CHASSIS ROLLS DYNO INSTALL TRIAXIAL ACCELEROMETER ON STEERING WHEEL AND SEAT FRAME SELECT TEST VEHICLE CROSS-PLOT RESULTANT STEERING WHEEL RMS ACCELERATION VS. ISO 5349 CURVES AND RESULTANT SEAT RMS ACCELERATION VS. ISO 2631 CURVES FOR EACH MEASUREMENT LOCATION, CALCULATE THE RESULTANT RMS ACCELERATION COLLECT ACCELERATION DATA AT EACH RESPONSE POINT IN THE X,Y,Z DIRECTIONS MODIFY: -MOUNT STIFFNESS (i.e. LOWER DUROMETER) -STEERING COLUMN THICKNESS INCREASE -REDUCE STRUCTURAL VIBRATION LEVELS DOES RMS ST. WHEEL ACCEL. LIE BELOW THE 8-HR ISO 5349 EXPOSURE CURVE? DOES RMS SEAT ACCEL. LIE BELOW THE 8-HR ISO 2631 EXPOSURE CURVE? NO NO YES YES INTERIOR VIBRATION ACCEPTABLE TRUCK CABIN VIBRATIONOPERATING TRUCK VIBRATION EVALUATION Detroit Diesel Standard Template.ppt

  5. SETUP TRUCK ON EPA APPROVED PASSBY SITE RUN VEHICLE AS PER SAE J366 PROCEDURE SELECT TEST VEHICLE IS PEAK SOUND PRESSURE LEVEL < 80 dBA? TRUCK COMPLIANT TO EPA CFR 205 YES NO MODIFY: -MECHANICAL FEATURES OF ENGINE (GEARS, STIFFENERS, COVERS, TREATMENTS) -CALIBRATION FEATURES (TORQUE LIMITING/ACCELERATION RATE) VEHICLE PASSBY NOISE LEVELOPERATING TRUCK PASSBY NOISE EVALUATION Detroit Diesel Standard Template.ppt

  6. SETUP TRUCK ON EPA APPROVED PASSBY SITE RUN VEHICLE AS PER SAE J1096 PROCEDURE SELECT TEST VEHICLE IS PEAK SOUND PRESSURE LEVEL < 85 dBA? TRUCK COMPLIANT TO EPA CFR 325 YES NO MODIFY: -MECHANICAL FEATURES OF ENGINE (GEARS, STIFFENERS, COVERS, TREATMENTS) -CALIBRATION FEATURES (TORQUE LIMITING/ACCELERATION RATE) VEHICLE STATIONARY NOISE LEVELNEUTRAL ENGINE RUN-UP NOISE EVALUATION Detroit Diesel Standard Template.ppt

  7. SETUP ENGINE ON DYNO STAND IN A SEMI-ANECHOIC CHAMBER OPERATE ENGINE AS PER SAE J1074 SELECT ENGINE FOR TEST IS ANY ONE MIC. POSITION SPL OR 4-MIC AVERAGE SPL > BEST IN CLASS? MODIFY: -REDUCE STRUCTURAL VIBRATION LEVELS -ADD STIFFENING TO BLOCK -REDUCE GEAR RATTLE -ADD C.L.D. TREATMENTS, BARRIERS -REDUCE COMBUSTION NOISE YES NO DYNO STAND SOUND LEVELS MEET OR EXCEED TARGET VALUES AND/OR BEST IN CLASS ENGINE DYNO STAND RADIATED NOISEOPERATING ENGINE SOUND LEVEL EVALUATION Detroit Diesel Standard Template.ppt

  8. SELECT ENGINE COMPONENT IMPACT THE EXCITATION POINT(S) 5 TIMES IN EACH DIRECTION (X,Y,Z) COLLECT DATA AT EACH RESPONSE POINT, AVERAGE OF 5 IMPACTS IN EACH DIRECTION (X,Y,Z) SELECT ACCELEROMETER RESPONSE POINT(S) SELECT IMPULSE HAMMER EXCITATION POINT(S) ARE ANY NAT. FREQ. BELOW 210 Hz? CHECK COMPONENTS IN THE OPERATING ENGINE DATA FLAG THESE AS CRITICAL FREQUENCY COMPONENTS REQUIRING FURTHER ANALYSIS PLOT FREQUENCY RESPONSE FUNCTION (FRF) FOR EACH RESPONSE POINT DETERMINE THE LOWEST NATURAL FREQUENCIES YES HIGH AMPLITUDE AT CRIT. FREQ. COMP’S? NO YES DOES COMPONENT FAIL IN FATIGUE? RESONANCES ABOVE 6TH ORDER FORCING FUNCTIONS YES NO COMPONENT NOT LIKELY TO FAIL DUE TO HIGH VIBRATION YES NO DOES CHANGE SHIFT NAT. FREQ. > 210 Hz? ENGINE FORCING FUNCTIONS NOT SUFFICIENT TO EXCITE RESONANCES SHAKER TEST AT LOWEST NAT. FREQ. & PEAK DISPLACEMENT FOR 10E06 CYCLES CHANGE COMP. FEATURES OR ADD SUPPORT (BRACKET, CLIP) OR ADD ISOLATION NO COMPONENT NOT LIKELY TO FAIL DUE TO HIGH VIBRATION COMPONENT VIBRATIONSTATIC ENGINE VIBRATION EVALUATION Detroit Diesel Standard Template.ppt

  9. SELECT ENGINE COMPONENT CONDUCT FULL LOAD (100% THROTTLE) SWEEP, 1050 RPM TO 1850 RPM, 90 SECONDS COLLECT TRI-AXIAL (X,Y,Z) DATA AT EACH RESPONSE POINT SELECT ACCELEROMETER RESPONSE POINT(S) (SAME AS FRF MEAS.) START ENGINE AND BRING UP TO OPERATING TEMPERATURE *** DATA ANALYSIS: 2D PK HOLD SPECTRUM 1. PK ACCEL. (0-500 Hz) 2. PK-TO-PK DISPL. (0-250 Hz) DATA ANALYSIS: 3D CAMPBELL PLOT 1. PK ACCEL. (0-500 Hz) 2. PK-TO-PK DISPL. (0-250 Hz) CONDUCT NO LOAD (0% THROTTLE) SWEEP, IDLE TO 2100 RPM, 90 SECONDS COLLECT TRI-AXIAL (X,Y,Z) DATA AT EACH RESPONSE POINT HIGH AMPL. < 210 Hz? LINES OF CONSTANT FREQ. WITH HIGH AMPL? LINES OF CONSTANT ORDER WITH HIGH AMPL? NO COMPONENT NOT LIKELY TO FAIL DUE TO HIGH VIBRATION NO YES YES YES COMPONENT VIBRATIONOPERATING ENGINE VIBRATION EVALUATION NO Detroit Diesel Standard Template.ppt

  10. CHANGE COMP. FEATURES OR ADD SUPPORT (BRACKET, CLIP) OR ADD ISOLATION ORDER AMPL. LEVELS NORMAL? YES *** NO IDENTIFY AND CORRECT ENGINE ORDER RELATED ISSUES, RE-MEASURE COMPONENT VIBRATION DOES CHANGE REDUCE AMPL. OR SHIFT FREQ? *** YES COMPONENT NOT LIKELY TO FAIL DUE TO HIGH VIBRATION NO DOES COMPONENT FAIL IN FATIGUE? SHAKER TEST AT LOWEST NAT. FREQ. & PEAK DISPLACEMENT FOR 10E06 CYCLES NO YES COMPONENT VIBRATION (CONTINUED)OPERATING ENGINE VIBRATION EVALUATION Detroit Diesel Standard Template.ppt

  11. SETUP ENGINE ON DYNO STAND (PERFORMANCE RM. OR DURABILITY STAND) MOUNT MAGNETIC PICKUP IN FLYWHEEL HOUSING AND AT FRONT OF CRANKSHAFT PERFORM FULL LOAD & NO LOAD ENGINE SWEEPS SELECT ENGINE FOR TEST IS THE ANGULAR DISPLACEMENT AT THE FLYWHEEL > 5 DEGREES? MODIFY: -MASS, DAMPING OR STIFFNESS OF ROTATIONAL COMPONENTS -PROVIDE ADDITIONAL STIFFENING TO CRANK CASE YES NO ENGINE EXHIBITS ACCEPTABLE TORSIONAL VIBRATION LEVELS ENGINE TORSIONAL VIBRATIONOPERATING ENGINE VIBRATION EVALUATION Detroit Diesel Standard Template.ppt

  12. Detroit Diesel Standard Template.ppt

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