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

ENGINE MOUNT VIBRATION OPERATING ENGINE VIBRATION EVALUATION SELECT TEST VEHICLE INSTALL TRIAXIAL ACCELEROMETER ON ACTIVE (ENGINE) SIDE AND PASSIVE (FRAME) SIDE OF EACH MOUNT SETUP TRUCK ON CHASSIS ROLLS DYNO 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 COLLECT ACCELERATION DATA AT EACH RESPONSE POINT IN THE X,Y,Z DIRECTIONS FOR EACH MOUNT CALCULATE TRANSMISSIBILITY: DIVIDE ACCELERATION OF FRAME SIDE BY ACCELERATION OF ENGINE SIDE IN X,Y,Z DIRECTIONS NO PLOT TRANSMISSIBILITY (X,Y,Z DIRECTIONS) AS A FUNCTION OF FREQUENCY (0-500 Hz) YES ISOLATORS EFFECTIVE AT VIBRATION ATTENUATION 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 Detroit Diesel Standard Template.ppt

TRUCK CABIN NOISE OPERATING TRUCK SOUND LEVEL EVALUATION SELECT TEST VEHICLE INSTALL MICROPHONE AT DRIVER’S RIGHT EAR LOCATION SETUP TRUCK ON SMOOTH ROAD 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) COLLECT A-WEIGHTED SOUND PRESSURE LEVEL AT EACH CONDITION FOR EACH CONDITION CALCULATE: -ONE THIRD OCTAVE SPECTRA -SOUND QUALITY METRICS (LOUDNESS, SHARPNESS) CROSS-PLOT: -OVERALL SPL -THIRD OCTAVES -SQ METRICS VS. FTL TARGET CURVES BEST-IN-CLASS CURVES YES INTERIOR SOUND LEVELS MEET OR EXCEED TARGET VALUES AND/OR BEST IN CLASS 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? NO Detroit Diesel Standard Template.ppt

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

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

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

ENGINE DYNO STAND RADIATED NOISE OPERATING ENGINE SOUND LEVEL EVALUATION SELECT ENGINE FOR TEST OPERATE ENGINE AS PER SAE J1074 SETUP ENGINE ON DYNO STAND IN A SEMI-ANECHOIC CHAMBER NO DYNO STAND SOUND LEVELS MEET OR EXCEED TARGET VALUES AND/OR BEST IN CLASS 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 Detroit Diesel Standard Template.ppt

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

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

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

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

Detroit Diesel Standard Template.ppt