nota engine

7/30/2019 nota engine

1/11

Three Factors of Sound

2) Pitch

1) Volume

3) Timbre

Psychologicalquantity

Physicalquantity

2) Frequency

(Hz)

1) Sound pressure

level (B,dB-A)

3) Spectrum structure

(dB, Hz, time)


2/11

Noise levelExample of generated

soundNoise level Example of heard sound

Human voice

(Musical instrument) db(A) Artificial sound Natural sound(1 ~ 2m)

Trumpet 130 Riveting (1m)

Shout (30cm) 110 Jet plane (600m) Dog's bark (1m)

A young man's sneeze 100 Concrete breaker (1m) Dog's bark in garden

Grade schooler's voice 90 Electric plane (1m) Dog's bark in neighborhood

Teacher's voice 70 Passenger car (100km/h) Frogs' chorusOrdinary voice, TV 60 Studying in classroom Sound of wave

Low voice 50 Office room Song of bird or insect

Whisper 40 Living room Hum of mosquito

Low whisper 30 Midnight in suburban residence area Sound of falling leaves

Sound of sleepingperson or eraser

20 Measurement limit of noise meter Drizzle

Low breathing sound ofsleeping person

10 Night of place deep in mountain Snowing sound

Holding breath 0 Limit of ordinary person's hearingHearing snow falling atmidnight

-10 Inside of very good soundless room Windless desert

Noise level of jet plane is large but necessary


3/11

Facts obtained from noise and vibration

Abnormality of

products

Emission of

sound

Uncomfortable

sound

Change of switch Switching

sound

Operating

sound

Comfortable

sound8/40

Roles of noise and vibration- Engine notifies us of abnormality or trouble by noise and

vibration and shows invisible troubled parts.

Be sure to catch noise and vibration.- If you miss noise or vibration, engine will break down!


4/11

2-3. Frequency analysis (Order analysis)

OA

27thorder

13.5thorder

40.5thorder

2nd

13.5th order (Oil pump 1st order)Oil pump with 13.5 teeth is used

Engine speed (PPM)

Accelerationamplitudele

vel

RPM x Order number

60= Hz

19/40

Engine 1st order means thephenomenon that occursonce in one rotation of crankshaft.

DisplayMode: AmplitudeTrace

CursorX:1330RPM

879msY:-18.5 dB/1 m/s^2

TMPG Running acceleration 8: Wtf.FFT1: OvPwr [3]-TM Oil p umpTMPG Running acceleration 8: Wtf.FFT1: Ord 40.5 [3]-TM Oil pumpTMPG Running acceleration 8: Wtf.FFT1: Ord 27 [3]-TM Oil pumpTMPG Running acceleration 8: Wtf.FFT1: Ord 13.5 [3]-TM Oil pumpTMPG Running acceleration 8: Wtf.FFT1: Ord 2 [3]-TM Oil pump


5/11

What is abnormal sound?

Engine noise

Machine noise Combustion noise

Abnormalsound

Sound that must notbe generated =

Abnormal sound

Sound of different type mixed in engine noise

- Metallic sound, rubbing sound, beating sound, whistling sound,

resonation sound, muffled sound, unclear sound, etc.

which have specific components, complicated forms, and arecontinuous or discontinuous among noises.

Auxiliary machinery sound

Electronic sound

Valve train drive sound


6/11

Examples of abnormal sound phenomenon

-500

-400

-300

-200

-100

0

100

200

300

400

500

(m/^2

0

500

1000

1500

2000

2500

ENG(rpm

-500

-400

-300

-200

-100

0

100

200

300

400

500

(m/^2)

0

500

1000

1500

2000

2500

ENG(rpm)

There isabnormal sound

There is notabnormal sound

36/4

Abnormal sound not generatedTentioner beat sound generated

Tentioner beat sound

Completeexplosion

Complete explosion

Vibrationle

vel

ENG

revolu

tion

RPM)

ENGrevo

lution

RPM)

Amplitudel

evel


7/11

Portions where abnormal soundis generated (Examples)

You are required toclassify sounds intonecessary ones andunnecessary ones

Sound andvibration judgment

device (PC)

CamshaftValve lifter

Rocker cover

Water pump

Metallic beat

This is thebasis!

Sound andvibration sensory

evaluation

Exhaust leakage and

abnormal sound


8/11

Examples of type and cause ofabnormal sound

Major category Sub-category Cause

- Abnormal sound

from valve train

- Beat from head - Large valve clearance

- Flaw of camshaft nose top

- Abnormal sound

from exhaustsystem

- Exhaust leakage

sound

- Flap from exhaust

system

- Omission of exhaust manifold

gasket

- Wrong connection of H/T cord

- Abnormal sound

from air intake

system

- Air intake sound - Omission of intake manifold

gasket

- Abnormal sound

from drive system

- Metallic beat

- Beating of chain

tentioner

- Large clearance in bearing metal

- Sticking of tentioner


9/11

Examples of type and causeof vibration

Major category Cause

- Large vibration - Crashing of spark plug gap

- Clogging of intake manifold

- Improper adjustment of AAC

- Improper adjustment of ignition timing

- Small vibration - Narrow valve clearance (Clogging)

Reference material


10/11

1. Outline

The abnormal sound and vibration of the engine aregenerated at many portions under various conditions.

To find out their causes, check the following items.

- You can understand abnormal sound or vibration whichcustomer feels.

- You can assume generating portion from abnormal sound

or vibration.

- Abnormal sound or vibration can be changed by changing

engine condition.

2. Start with sensory evaluation!

- Sound that is not heard cannot be analyzed or judged.

- Listen to various sounds and record them.

Abnormal sound


11/11

Plan of making abnormal sound generating enginemodel (draft) - Executed for only 3 items

No Trouble name Phenomenon

1 - Large valve clearance - Chatter is generated

from around cylinder

head

2 - Wrong connection of H/T

cord

- Abnormal exhaust

sound

- Large vibration

3 - Intake manifold gasket

Catching of foreign matter

- Air suction sound

- Large vibration4 - Crashing of spark plug gap - Large vibration

- This model will be manufactured by PMT.

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