Design of an Engine Crankshaft

21st March 2011

Sakib SarkerDarlington

Midrange Technical Operations (MTO)

“ Take the best that exists and make it better. When it does not exist, design it.”

-Sir Henry Royce

2

3Design and Validation of a Crankshaft

4Design and Validation of a Crankshaft

Crankshaft can be found in any kind of reciprocating engine that translates linear piston motion into rotation. i.e. Engines ofHeavy duty truck, cars, racing car, bus, mini car, aircraft.

Design and Validation of a Crankshaft5

Conceptual design

•Major functions are fixed•Setting of Structural relationships of the principal components•Sufficient details to provide approximate costs, weights•Assured overall dimensions and feasibility of crank

Major crankshaft dimensions must be chosen early in the engine design process as they affect overall engine dimensions.

Design and Validation of a Crankshaft6

Process analysis and selection

crank stressintegrity of the jointsimpact of the crank on the block stress and deformation

Design and Validation of a Crankshaft 7

The virtual procedure of analysis:

1)Run full crank reduced model (dynamic) to calculate reactions and torques.2)Model entire crankshaft with FEM

3)Constrain the model at the flywheel end4)Run analysis applying all possible loads5)Scale and sum up the FE results for each crank angle

Design and Validation of a Crankshaft 8

Design and Validation of a Crankshaft 9

Test

fatigue through the crank web.fatigue through the pin journal, with the crack initiation starting at the oil hole. run calibration curve, calculate test strain levels, set control parameters, run test and inspect the specimen surface.

Design and Validation of a Crankshaft 10

Production

Forging

Casting

Billet

Design and Validation of a Crankshaft 11

Quality improvement

Hardening- using induction hardened bearing surfacesFatigue strength- increased by using a radius at the ends of each main and crankpin bearingCounterweights-helps to negate the flexing of the crank

Design and Validation of a Crankshaft 12

Supportive materials through Design and Validation:

Six SigmaISO 9001: 2000 BS 7000Health and Safety Executive (HSE)

Design and Validation of a Crankshaft 13

Step 1- conceptual designStep 2- process analysis and selectionStep 3- testStep 4- productionStep 5- improvement

Design and Validation of a Crankshaft 14

Any questions?

Design and Validation of a Crankshaft 15