Dynamics of an IC Engine Valvetrain

ByMr. Narayan Sanjay Susange

MIS : 121495019Under the Guidance of

Dr. D. N. Malkhede (COEP)Dr. C. M. Sewatkar (COEP)Mr. Naresh Gandhi (KOEL)

Mr. Aniket Basu (KOEL)

DISSERTATION REPORT

ON

Outline Project definition. Introduction to Valvetrain. Literature Review Steps in Project. Simulation Work. Validation. Design Modification. Conclusion

Project Definition

To study the dynamic behavior of valvetrain system at

elevated 3300 rpm from it’s max rated 3000 rpm.

Further attempt to reduce the dynamic impact of these

elements on performance of valvetrain.

Introduction to Valvetrain. Valve Valve Seat Valve Spring Rocker Arm Push Rod Tappet Camshaft

Literature Review Dynamic Phenomenon prediction

Steps in Project Literature Review Modelling Parts in Creo. FEA Analysis in HyperMesh. VALKIN and VALDYN model in RICARDO. Validate model with experimental results. Design modification Interpret results.

Need of Project Typical engine used in fire fighting. Requirement of high capacity engine is generated from

marketing dept. Time restriction for building new engine. Started modifying existing engine to match requirement. After modification found that valvetrain is weakest

element. Started generating data with experimentation.

Simulation RICARDO VALKIN and VALDYN. Dimensional inputs are taken from model. Mass and stiffness values are taken from FEA model. Run the simulation at various rpm such 840, 1800, 2600,

3000 and 3300. Experimental results of pushrod forces at 3000 rpm are

taken validation. Model Validated.

VALKIN Model

Lift. Velocity. Acceleration. Wear rate. Contact

Forces. Contact

stresses. Oil film

thickness.

Lift. Velocity. Acceleration. Dynamic

Forces.

VALDYN Model

Inputs for VALDYN ModelSr. No. Ricardo Model Components Damping

Stiffness MassDamping Coefficient

(N/mm) (gm)

1 X support 1750 82642 926.435711 0.1

2 Y support 1750 70744 1082.24726 0.1

3 1/2 rocker + valve 337.9829071 24213.075 209.68 0.075

4 Valve seat 348.4250278 100000 30.35 0.1

5 1/2 pushrod + 1/2 rocker 140.063821 17032.361 115.18 0.05

6 Half pushrod 173.6294385 27531.673 109.5 0.05

7 Camshaft tappet 2402.642295 34000 38.5 1.05

8 Camshaft bending 387.2983346 100000 150 0.05

9 Rocker + pushrod 1/3 387.2983346 100000 150 0.05

10 2/3 pushrod 229.6153616 19841.27 118.1 0.075

Pushrod Forces @ 3300 rpm

Validation of Simulation Model

0 1000 2000 3000 4000 5000 6000 7000 8000

-100

0

100

200

300

400

500

600

700

800

PUSHROD FORCE

Time in milliseconds

Forc

e in

N

Simulation Model Result Experimental Result

@ 3000 RPM

Valve Lift

Valve Seat Force

Rocker Valve Contact Forces

Tappet Force

Cam Forces

Spring Surge

-20 -5 10 25 40 55 70 85 100 115 130 145 1600

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

Cam ProfileNew profile

old profile

Rotation Angle in Deg

Cam

Lift

in m

m

Design Modification

Spring Surge

Valve Lift

Valve Seat Forces

Rocker Valve Contact Forces

Push Rod Forces

Tappet Force

Cam Force

0 1000 2000 3000 4000 5000 6000 7000 8000-50150350550750950

11501350155017501950215023502550275029503150

Old Cam

Updated cam

Time in milliseconds

Forc

e in

N

Pushrod Forces Comparison

Sheet Data of Comparison

Model- 2600 half model

3000 half model

3300 half model

2600 half model with updated cam profile

3300 half model with updated cam profile

Contact loss Rocker-Valve 1 2 4 0 1

Jump in mm 0 -0.4 1 0 0.2

Bounce in mm 0.015 0.25 0.4 0 0

Spring Surge in mm 1 2.75 3.6 0.1 1

Push Rod Forces in N 2650 2800 (5.6%) 3080 (16.22%) 1350 (-49.50) 1850 (39.90%)

Valve Forces in N 950 1700 (78.50%) 1350 (42.10%) 680 (-28.42) 1200 (-11.11%)

Tappet Forces in N 2840 3180 (12%) 3250 (14.43%) 1450 (-48.94%) 2050 (-36.92%)

Cam Forces in N 3000 3450 (15%) 3420 (14%) 1500 (-50%) 2200 (-35.67%)

Valve Seat Force in N 2750 2250 (-18.18%) 2300 (-16.36%) 2250 (-18.18%) 1850 (-19.56%)

Valve Seat Bounce pts 2 4 4 2 1

Conclusion

At 3000 & 3300 rpm, Valvetrain shows significant dynamic Effects in terms of Spring surge, Valve jump and bounce, Pushrod forces and contact loss.

This will definitely affect the valvetrain performance and it’s life.

Modified cam profile suppresses almost all the unaccepted dynamic effects which is also a better for normal rpm run.

Further modification in valvetrain parts like pushrod, tappet will not enhance dynamic effects.

Thank you