Crankshaft, Bearings and Related Component Fundamentals pg 248

Question 1

List 2 functions of the crankshaft.

Answer 1

A. Converts the reciprocating motion of the piston and connecting rods to rotary motion.
B. Drives the camshaft and engine accessories.

Question 2

Identify the parts of the crankshaft in figure 45.

Answer 2

A. Nose
B. Web.
C. Fillet radius.
D. Counterweights.
E. Flange.

Question 3

What is the purpose of the internal drilling of the crankshaft?

Answer 3

The internal drillings provide a path for oil to travel from the main bearing journals to the connecting rod journals.

Question 4

Crankshafts used in medium and high speed diesel engines are usually:

Answer 4

B. One piece forged alloy steel.

Question 5

The crankshafts used in diesel engines are usually hardened to improve the wear characteristics of the: 
A. Nose
B. Journals
C. Webs.
D. Counterweights

Answer 5

B. Journals

Question 6

List four factors that determine the arrangement of the throws on a crankshaft.

Answer 6

A. Number and arrangement of the cylinders.
B. Firing Order
C. Engine Balance
D. Main Bearing Loads

Question 7

Determine the number of degrees between firing impulses on a two stroke cycle engine with sixteen cylinders.

Answer 7

22.5 Degrees

Question 8

Determine the mating cylinders for a four stroke cycle, eight cylinder engine with a firing order of 1-5-4-8-6-3-7-2.

Answer 8

1/6, 5/3, 4/7, 8/2

Question 9

An unbalance engine would have reduced:

Answer 9

C. Mechanical efficiency.

Question 10

List the 3 basic functions of the flywheel.

Answer 10

A. Smoothes out engine operation by storing and releasing energy.
B. Carries the ring gear.
C. Provides a mounting and friction surface surface for the clutch assembly.

Question 11

The balance weights used in some four stroke cycle diesel engines:
A. Absorb and release energy to smooth engine operation.
B. Counterbalance inertia forces generated by the piston and rod assemblies.
C. Counterbalance torsional forces generated by the piston and rod assemblies.
D. Counteract inertia forces.

Answer 11

B. Counterbalance inertia forces generated by by the piston and rod assemblies.

Question 12

List 2 types of vibration dampners used on diesel engines.:

Answer 12

A. Rubber element.

B. Viscous

Question 13

Briefly explain the purpose of a vibration dampner.

Answer 13

The vibration dampner counteracts or opposes the twisting forces acting on the crankshaft, reducing torsional vibration.

Question 14

The front and rear crankshaft seals:
A. Prevent pressurized oil from entering the crankcase.
B. Maintain crankcase pressure.
C. Control lubrication of the front and rear main bushings.
D. Prevent splash oil from leaking out around the rotating crankshaft.

Answer 14

D. Prevent splash oil from leaking out around the rotating crankshaft.

Question 15

List two functions of the crankshaft gear.

Answer 15

A. Transfers power to drive engine components and accessories.
B. Time the crankshaft to the camshaft using marks on the gears.

Question 16

List the two types of friction bearings used in diesel engines.

Answer 16

A. bushing

B. shell

Question 17

What bearing term is represented by dimesion A in figure 46?

Answer 17

Spread

Question 18

Locating lugs and dowels are used to:
A. Stop bearing shells from rotating during engine operation.
B. Index the main caps to the cylinder block.
C. Position the bearing shells in the main bearing bore.
D. Ensure the initial seating of the bearing during assembly.

Answer 18

C. Position the bearing shells in the main bearing bore.

Question 19

List four basic properties that friction type bearing materials must posses.

Answer 19

A. Embeddability
B. Conformabillity
C. Fatigue resistance.
D. Corrosion resistance.

Question 20

Briefly explain the purpose of bearing crush.

Answer 20

The press fit that seats the bearing halves to provide good heat transfer and keep them from rotating in the bore.

Question 21

What is the purpose of an oil spreader groove?

Answer 21

An oil spreader groove aids in oil distribution across the bearing face.

Question 22

What is the purpose of bearing clearance?

Answer 22

Bearing clearance allows oil to flow between the bearing surface and the shaft.

Question 23

List two purposes of the oil film between the bearing and the crankshaft journal.

Answer 23

A. reduces friction

B. Carries heat away from the bearing and journal.

Question 24

Maintaining the film of oil between the bearing and the crankshaft journal is dependent on engine oil pressure and the principle of

Answer 24

hydrodynamic lubrication.